TWI910358B - Liquid crystal alignment agents, liquid crystal alignment films, liquid crystal elements, polymers, and methods for manufacturing the same. - Google Patents

Abstract

This invention provides a liquid crystal alignment agent that exhibits high reliability relative to heat resistance and can form a liquid crystal alignment film that displays good liquid crystal alignment even when the film thickness of the liquid crystal alignment film is reduced due to poor coating, etc. This invention contains a polymer (P) in the liquid crystal alignment agent, said polymer (P) having at least one of the groups of structural units selected from formulas (1) to (5). In formulas (1) to (5), one of ^X1 and ^X2 is a monovalent group represented by formula (6), and the other is ^-OR4 . ^R4 is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. ^A1 is an methyl group, an ethyl group, a sulfur atom, or an oxygen atom. In formula (6), ^R1 is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. ^R2 is an alkyl group. ^R3 is a monovalent organic group having 1 or more carbon atoms.

Description

Liquid crystal alignment agents, liquid crystal alignment films, liquid crystal elements, polymers, and methods for manufacturing the same.

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

Polyimide is generally used as the polymer component of liquid crystal alignment films due to its high heat resistance. However, polyimide has low solvent solubility, so it is believed that when larger hydrophobic groups (such as mesogen structures) are introduced into the polymer side chains, the solubility is insufficient, resulting in reduced coatability. Therefore, it has been proposed to use acrylic polymers or styrene-maleimide polymers instead of polyimide as materials for liquid crystal alignment films (see, for example, Patent 1).

[Prior Art Documents] [Patent Documents] [Patent Document 1] International Publication No. 2018/074547

[Problem Solved by the Invention] Liquid crystal elements (LCDs) are used in a wide range of applications, from LCD televisions to smartphones and personal computers (PCs). With this versatility, it is envisioned that LCDs will be driven for longer periods and used under harsher temperature conditions than ever before. Furthermore, the increasing precision of LCDs demands higher coating uniformity and a liquid crystal alignment film that can stably exhibit good liquid crystal alignment even when it becomes a thin film due to poor coating.

Liquid crystal alignment films are typically formed by coating a liquid crystal alignment agent, which is a polymer component dissolved or dispersed in a solvent, onto a substrate and then heating it at a high temperature (e.g., 200°C to 250°C). However, if the polymer component lacks sufficient heat resistance, thermal decomposition can occur during film formation due to the heating process. The resulting components become impurities, leading to reduced electrical properties and concerns about decreased reliability. From the perspective of further improving quality in recent years, liquid crystal alignment agents are required to have minimal decomposition products formed during film formation, maintain performance even when driving liquid crystal elements for extended periods, exhibit high reliability relative to heat resistance, and demonstrate good liquid crystal alignment even when the film thickness decreases due to poor coating.

The present invention was made in view of the above circumstances, and its main purpose is to provide a liquid crystal alignment agent that has high reliability in terms of heat resistance and can form a liquid crystal alignment film with good liquid crystal alignment even when the film thickness of the liquid crystal alignment film is reduced due to poor coating or other reasons.

[Technical Means for Solving the Problem] To solve the aforementioned problem, the inventors focused on introducing the following structure into the polymer component of the liquid crystal alignment agent: This structure is transformed into a heat-resistant closed-ring structure through heating during film formation, and the conversion rate to the closed-ring structure is high, with minimal reversible reactions. Specifically, the present invention employs the following means to solve the aforementioned problem.

[1] A liquid crystal alignment agent comprising a polymer (P) having at least one of the structural units selected from the group consisting of structural units represented by formula (1), formula (2), formula (3), formula (4), and formula (5). [Chemical 1] (In formulas (1) to (5), one of ^X1 and ^X2 is a monovalent group represented by formula (6) below, and the other is ^-OR4 . ^R4 is a hydrogen atom or a monovalent organic group with more than 1 carbon atom. ^A1 is an enylmethyl, enylethyl, sulfur atom or oxygen atom. m is 1 or 2. "*1" indicates a bond with the atoms that form the main chain of the polymer.) [Chemistry 2] (In formula (6), ^R1 is a hydrogen atom or a monovalent organic group with 1 or more carbon atoms. ^R2 is an alkyldiyl group. ^R3 is a monovalent organic group with 1 or more carbon atoms. "*" indicates a bond.)

[2] A liquid crystal alignment film, formed using a liquid crystal alignment agent as described in [1]. [3] A liquid crystal element comprising the liquid crystal alignment film as described in [2]. [4] A polymer having at least one of the structural units selected from the group consisting of structural units represented by formula (1), structural units represented by formula (2), structural units represented by formula (3), structural units represented by formula (4), and structural units represented by formula (5).

[5] A method for manufacturing a polymer, comprising: a step of reacting a polymer (x) with a compound (y), said polymer (x) having a structural unit derived from at least one compound selected from the group consisting of a compound represented by formula (11), a compound represented by formula (12), a compound represented by formula (13), and a compound represented by formula (14), said compound (y) being represented by formula (15); and a step of reacting the reaction product of said polymer (x) and said compound (y) with an esterifying agent. [Chemical 3] (In formula (11), n is 0 or 1. In formulas (13) and (14), ^A1 is an elongated methyl group, an elongated ethyl group, a sulfur atom, or an oxygen atom. m is 1 or 2.) [Chemistry 4] (In formula (15), ^R1 is a hydrogen atom or a monovalent organic group with 1 or more carbon atoms. ^R2 is an alkyldiyl group. ^R3 is a monovalent organic group with 1 or more carbon atoms.)

[Effects of the Invention] Liquid crystal alignment agents containing the aforementioned polymer (P) exhibit high reliability in terms of heat resistance and can form liquid crystal alignment films that stably display good liquid crystal alignment even when the film thickness of the liquid crystal alignment film is reduced due to poor coating or other reasons.

The following provides a detailed explanation of matters related to the form of this invention. Furthermore, in this specification, the term "alkane" encompasses chain-like hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons. "Chain-like hydrocarbons" refers to linear or branched hydrocarbons that do not contain a ring structure but are composed solely of a chain-like structure. These can be saturated or unsaturated. "Alicyclic hydrocarbons" refers to hydrocarbons that contain only an alicyclic hydrocarbon structure as a ring structure and do not contain an aromatic ring structure. This does not necessarily require the alicyclic hydrocarbon structure to be present; it also includes groups that have a chain-like structure in a portion of their structure. The term "aromatic hydrocarbon" refers to a hydrocarbon group that contains an aromatic ring structure as its ring structure. It does not necessarily need to consist solely of an aromatic ring structure; it may also include chain structures or alicyclic hydrocarbon structures in a portion of it. The term "main chain" of a polymer refers to the longest "trunk" portion of the polymer's atomic chain. The term "side chain" of a polymer refers to the portions that branch off from the "main chain" of the polymer. The term "organic group" refers to a group of atoms formed by removing any hydrogen atoms from a carbon-containing compound (i.e., an organic compound).

<<Liquid Crystal Alignment Agent>> The liquid crystal alignment agent of the present invention contains the following polymer (P). Polymer (P): a polymer having at least one structural unit (hereinafter also referred to as "structural unit U1") selected from the group consisting of structural units represented by the following formula (1), structural units represented by the following formula (2), structural units represented by the following formula (3), structural units represented by the following formula (4), and structural units represented by the following formula (5) [Chemical 5] (In formulas (1) to (5), one of ^X1 and ^X2 is a monovalent group represented by formula (6) below, and the other is ^-OR4 . ^R4 is a hydrogen atom or a monovalent organic group with more than 1 carbon atom. ^A1 is an enylmethyl, enylethyl, sulfur atom or oxygen atom. m is 1 or 2. "*1" indicates a bond with the atoms that form the main chain of the polymer.) [Chemistry 6] (In formula (6), ^R1 is a hydrogen atom or a monovalent organic group with 1 or more carbon atoms. ^R2 is an alkyldiyl group. ^R3 is a monovalent organic group with 1 or more carbon atoms. "*" indicates a bond.) The components contained in the liquid crystal alignment agent of the present invention, as well as other components that may be arbitrarily added as needed, will be described below.

<Polymer (P)> (Structural Unit U1) In formulas (1) to (5), one of ^X1 and ^X2 is a monovalent group represented by formula (6). In formula (6), the monovalent organic group represented by ^R1 with 1 or more carbon atoms is preferably a monovalent hydrocarbon with 1 to 10 carbon atoms, more preferably an alkyl or phenyl group with 1 to 6 carbon atoms, and even more preferably an alkyl group with 1 to 3 carbon atoms. Among them, the group represented by ^R1 is preferably a hydrogen atom or a methyl group.

The alkyldiyl group represented by ^R2 can be either linear or branched. From the viewpoint of obtaining a liquid crystal element that maintains performance even under long-term driving (i.e., high long-term heat resistance) and exhibits good alternating current (AC) retention characteristics, ^R2 is preferably a group bonded to the nitrogen atom in formula (6) via an exomethyl group ( _-CH2- ). Specifically, ^R2 is preferably a linear alkyldiyl group with 1 to 5 carbon atoms, more preferably a linear alkyldiyl group with 1 to 3 carbon atoms, and even more preferably an exomethyl or exoethyl group.

Examples of monovalent organic groups represented by ^R3 include: monovalent hydrocarbons with 1 to 20 carbon atoms; monovalent hydrocarbons with 1 to 20 carbon atoms whose methylene groups are substituted with one or more of the groups consisting of -O-, -S-, -CO-, -COO-, -NR ^10- , -NR ¹⁰ -CO-, -NR ^10- COO-, and -N=N- (hereinafter also referred to as "monovalent group ^RE "); monovalent hydrocarbons with 1 to 20 carbon atoms whose hydrogen atoms in the hydrocarbon or monovalent group RE are substituted with fluorine atoms, hydroxyl groups, cyano groups, carboxyl groups, etc.; and monovalent groups with heterocycles. ^R10 is a hydrogen atom or a monovalent organic group. Examples of monovalent organic groups represented by R ¹⁰ include alkyl groups with 1 to 6 carbon atoms, phenyl groups, tert-butoxycarbonyl groups, hydroxyalkyl groups, etc.

The monovalent organic group represented by R ³ is particularly preferably a group comprising at least one functional group selected from the group consisting of a basic group, a group that generates a basic group by heating, an acidic group, a group that generates an acidic group by heating, a crosslinking group, a group that generates a crosslinking group by heating, a photoaligning group, a perpendicularly aligned group, a photoinitiator group, an electron transport group, and a hole transport group.

• When the monovalent organic group represented by R ³ has a basic group and a group that generates a basic group through heating, nitrogen-containing groups can be listed as the basic group. Specific examples of nitrogen-containing groups include: primary amino groups, secondary amino groups, tertiary amino groups, and nitrogen-containing heterocyclic groups. Specific examples of the case where the monovalent organic group represented by R ³ has a basic group and a group that generates a basic group through heating can be listed as the groups represented by the following formulas (r1-1) to (r1-4). [Chemistry 7] (In equations (r1-1) to (r1-4), PG is a monovalent thermally deionized group. "*" indicates a bond.)

The group represented by formula (r1-2) is desorbed by heating, thereby generating an alkaline group. From the viewpoint of simplifying the process by desorbing the group PG during the process of coating a liquid crystal alignment agent onto a substrate and heating it to form a liquid crystal alignment film, the group PG is preferably a group that decomposes at a temperature of 120°C to 300°C and is replaced by a hydrogen atom. Specifically, it is preferably tert-butoxycarbonyl (Boc group) or 9-fluorenylmethoxycarbonyl, and particularly preferably tert-butoxycarbonyl.

• When the monovalent organic group represented by R ³ has an acidic group and a group that generates an acidic group through heating, the acidic group can be categorized as follows: carboxylic acid group, phosphoric acid group, phosphorous acid group, sulfonic acid group, and acetic acid group, etc. Among these, the acidic group possessed by R ³ is preferably a carboxylic acid group or an acetic acid group. Preferred specific examples of the case where the monovalent organic group represented by R ³ has an acidic group and a group that generates an acidic group through heating are the groups represented by the following formulas (r2-1) to (r2-4), respectively. [Chemistry 8] (In formulas (r2-1) to (r2-4), ^R11 is a hydrogen atom or an alkyl group. PG is a monovalent thermally deionizable group. "*" indicates a bond.)

The groups represented by formulas (r2-2) and (r2-4) are desorbed by heating, thereby producing acidic groups. Examples of groups PG include those bonded via a tertiary carbon atom to an oxygen atom in formula (r2-2) or a nitrogen atom in formula (r2-4). Specifically, examples include tert-butyl, 1-cyclopentylethyl, 1-cyclohexylethyl, 1-norbornylethyl, and 1-phenylethyl.

• When the monovalent organic group represented by R ³ has a crosslinking group and a group that generates a crosslinking group through heating, examples of such crosslinking groups include: (meth)acrylic, alkenyl, vinylphenyl, β-hydroxylamine, furanyl, epoxy, cyclic carbonate, alcoholic hydroxyl, phenolic hydroxyl, isocyanate, protected isocyanate, trialkoxysilyl, maleimino, etc. Specific examples of the monovalent organic group represented by R ³ having a crosslinking group and a group that generates a crosslinking group through heating include the groups represented by formulas (r3-1) to (r3-9) below. [Chemical 9] (In formulas (r3-1) to (r3-9), ^R12 is a hydrogen atom or an alkyl group. ^R13 is a hydrogen atom or a methyl group. "*" indicates a bond.)

• Photoalignment groups Photoalignment groups are functional groups that can impart anisotropy to films through photo-reactions such as photoisomerization, photodimerization, photo-Fries rearrangement, or photodecomposition induced by light irradiation.

Specific examples of photoalignment groups include: azobenzene-containing groups with azobenzene or its derivatives as the basic skeleton; cinnamic acid-containing groups with cinnamic acid or its derivatives (cinnamic acid structure) as the basic skeleton; chalcone-containing groups with chalcone or its derivatives as the basic skeleton; benzophenone-containing groups with benzophenone or its derivatives as the basic skeleton; coumarin-containing groups with coumarin or its derivatives as the basic skeleton; cyclobutane-containing structures with cyclobutane or its derivatives as the basic skeleton; stilbene-containing groups with stilbene or its derivatives as the basic skeleton; and phenyl benzoate-containing groups with phenyl benzoate or its derivatives as the basic skeleton. Among them, the photo-aligning group is preferably selected from at least one of the group consisting of azobenzene-containing groups, cinnamic acid-containing groups, chalcone-containing groups, stilbene-containing groups, cyclobutane-containing groups, and phenyl benzoate-containing groups. In terms of high light sensitivity and ease of incorporation into the polymer, groups containing cinnamic acid-containing groups or azobenzene-containing groups are particularly preferred.

Specific examples of photoalignment groups include those represented by equations (r4-1) to (r4-4) below. [Chemistry 10] (In formulas (r4-1) to (r4-4), R is a hydrogen atom or a monovalent organic radical. ^X3 is -O- or -NH-. "*" indicates a bond.)

• Vertically oriented groups are groups that exhibit the property of vertically oriented liquid crystal molecules without relying on light irradiation, and are groups that impart a pre-tilt angle to the liquid crystal. Specific examples of vertically oriented groups include: alkyl groups with 3 to 30 carbon atoms, fluorinated alkyl groups with 3 to 30 carbon atoms, alkoxy groups with 3 to 30 carbon atoms, groups represented by the following formula (9), and groups with 17 to 51 carbon atoms having a steroid skeleton, etc. [Chemistry 11] (In formula (9), ^A1 to ^A3 are independently extended phenyl or extended cyclohexyl, and may also have substituents in the ring portion. ^R21 is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms with at least one hydrogen atom substituted by a fluorine atom, an alkoxy group having 1 to 20 carbon atoms substituted by a fluorine atom, or a fluorine atom. ^R22 and ^R23 are independently single bonds, -O-, -COO-, -OCO-, or alkyldiyl groups having 1 to 3 carbon atoms. k, m, and n are integers greater than 0 that satisfy 1 ≤ k + m + n ≤ 4. In the case where ^R21 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a fluorine atom, k + m + n ≥ 2 is satisfied. "*" indicates a bond.)

Specific examples of the base represented by formula (9) include, for example, the bases represented by formulas (r5-1) to (r5-7) below, but are not limited to these. Substituents that may be present in the ring moiety as ^A1 to ^A3 include, for example, fluorine atoms, alkyl groups having 1 to 3 carbon atoms, alkoxy groups having 1 to 3 carbon atoms, etc. [Chemical 12] (In formulas (r5-1) to (r5-7), R is a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a fluoroalkyl group having 1 to 20 carbon atoms. "*" indicates a bond.)

• Photoinitiator Group A photoinitiator group is a site that utilizes light to generate polymerization initiation capabilities or has a photosensitizing effect, and is a group with a structure originating from a compound (photoinitiator) capable of initiating polymerization of polymerizable components by irradiation with radiation such as visible light, ultraviolet light, far-ultraviolet light, electron beams, and X-rays. Preferably, the photoinitiator group is a group with a structure originating from a free radical polymerization initiator capable of generating free radicals by light irradiation. Specifically, examples include groups with structures originating from compounds containing free radical generating groups, such as benzyl ketone compounds, benzoin compounds, ketone compounds, acetophenone compounds, benzophenone compounds, thioxanthraquinone compounds, and anthraquinone compounds.

Specific examples of photoinitiator groups include those represented by formulas (r6-1) to (r6-11) below. [Chemistry 13] (In formulas (r6-1) to (r6-11), R is a hydrogen atom or an alkyl group. "*" indicates a bond.)

• Electron-transporting and hole-transporting groups As electron-transporting groups, examples include groups with ring structures such as imidazole, pyridine, pyrazine, oxadiazole, triazine, triazole, oxazole, isoxazole, thiazole, isothiazole, thiazolyl, thiadiazole, quinoxaline, quinoline, and isoquinoline. As hole-transporting groups, examples include groups with aromatic amine structures (triphenylamine, diphenylamine, etc.), carbazole, and thiophene rings.

The other of ^X1 and ^X2 is ^-OR4 . ^R4 is a hydrogen atom or a monovalent organic group with 1 or more carbon atoms. In terms of maintaining stable liquid crystal alignment even when the liquid crystal alignment film becomes a thin film due to poor coating, etc., and sufficiently reducing the generation of AC retention, ^R4 is preferably a monovalent organic group with 1 or more carbon atoms. As a monovalent organic group, the same group as the one exemplified as the monovalent organic group represented by ^R3 can be listed. If ^R4 is a monovalent organic group with 1 or more carbon atoms, the separation of the above formula (6) caused by the reverse reaction during post-baking can be suppressed, and the generation of AC retention can also be suppressed when the liquid crystal alignment film becomes a thin film, which is preferable in this respect. Furthermore, it is preferable to include polymer (P) and other polymers in the liquid crystal alignment agent to ensure phase separation. Among these, from the viewpoint of the structural stability of the side chains, ^R4 is preferably a monovalent hydrocarbon having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms.

Furthermore, in Equation (1) of Equations (1) to (5), the two bases "-CO- ^X1 " and "-CO- ^X2 " adopt specific isomer structures, and the two bases exist on the same side. In contrast, Equations (2) to (5) do not specifically specify the isomer structures of the two bases "-CO- ^X1 " and "-CO- ^X2 ".

From the perspective of heat resistance and ease of incorporating the group represented by formula (6) into the side chains, polymer (P) is preferably a polymer having structural units derived from monomers containing polymerizable carbon-carbon unsaturated bonds. The types of monomers containing polymerizable carbon-carbon unsaturated bonds constituting polymer (P) are not particularly limited, and examples include: maleic anhydride compounds, (meth)acrylic acid compounds, aromatic vinyl compounds, maleimide compounds, olefinic hydrocarbons, cycloolefinic hydrocarbons, etc. The "*1" in formulas (1) to (5) is preferably a bond bonded to a carbon atom in the main chain constituting the polymer.

The content of structural unit U1 in polymer (P) is preferably 5 mol% or more, and more preferably 10 mol% or more, relative to all structural units constituting polymer (P). Furthermore, the content of structural unit U1 in polymer (P) is preferably 90 mol% or less, and more preferably 80 mol% or less, relative to all structural units constituting polymer (P). If the content of structural unit U1 is within the aforementioned range, even under heating conditions during prolonged film formation, a high voltage retention rate can be maintained. Even if the liquid crystal alignment film thickness decreases due to poor coating, etc., image retention is less likely to occur, and a significant improvement in long-term heat resistance can be achieved. These aspects are preferred.

(Other Structural Units) The polymer (P) may be a polymer containing only structural unit U1, but may also contain structural unit U1 and other structural units different from structural unit U1. As other structural units, structural units that do not have the structural unit represented by the above formula (6) may be used. Specifically, examples include: structural unit U2 having a cyclic carbonate structure; structural unit U3 having -COOR ⁵ (wherein R ⁵ is a monovalent thermally deionizable group); structural unit U4 derived from the group consisting of compounds selected from compounds represented by the following formula (8-1), compounds represented by the following formula (8-2), N-substituted aromatic maleimides, olefins, and compounds that produce isocyanate groups by heating, etc.

• Structural Unit U2 When the polymer (P) has a structural unit U2, epoxy groups can be generated by heating (preferably during the process of coating a liquid crystal alignment agent onto a substrate and heating to form a liquid crystal alignment film). The generated epoxy groups function as cross-linking groups, thereby further improving the long-term heat resistance of the obtained liquid crystal element, which is preferable in this respect.

Structural unit U2 is preferably derived from a monomer containing polymeric carbon-carbon unsaturated bonds and cyclic carbonate groups. Specifically, structural units represented by equations (10-1) to (10-3) can be listed below. [Chemistry 14] (In formulas (10-1) to (10-3), ^R21 , ^R22 , and ^R23 are each independently a hydrogen atom or a monovalent organic group. ^R24 is a hydrogen atom or a methyl group. ^Z1 is an oxygen atom or -NH-. ^X1 is a single bond or a divalent linker. n1 is 0 or 1. n2 is an integer from 0 to 2.)

The content of structural unit U2 in polymer (P) is preferably 2 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, relative to all structural units constituting polymer (P). Furthermore, the content of structural unit U2 in polymer (P) is preferably 60 mol% or less, more preferably 55 mol% or less, relative to all structural units constituting polymer (P). If the content of structural unit U2 is within the aforementioned range, thermal decomposition of the polymer can be sufficiently suppressed during the heating process during film formation. Even if the thickness of the liquid crystal alignment film thins due to poor coating, etc., image retention is less likely to occur, and long-term heat resistance improvement can be fully obtained. The polymer (P) may have only one type of structural unit U2, or it may have two or more types.

• Structural Unit U3 When the polymer (P) has a structural unit U3, carboxyl groups can be generated by heating (preferably during the process of coating a liquid crystal alignment agent onto a substrate and heating to form a liquid crystal alignment film). The generated carboxyl groups function as crosslinking groups, thereby further improving the long-term heat resistance of the obtained liquid crystal element, which is preferable in this respect.

Specific examples of the base "-COOR ⁵ " include the structure represented by the following formula (X-1), the acetal ester structure of carboxylic acids, and the ketal ester structure of carboxylic acids. [Chemistry 15] (In formula (X-1), ^R31 , ^R32 , and ^R33 are either (i) or (ii) below. (i) ^R31 , ^R32 , and ^R33 are each independently an alkyl group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon having 3 to 20 carbon atoms. (ii) ^R31 and ^R32 represent alicyclic hydrocarbon structures or cyclic ether structures having 4 to 20 carbon atoms that are bonded together with each other and together with the carbon atoms bonded to ^R31 and ^R32 . ^R33 is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms. "*" indicates a bond.)

Specific examples of the structure represented by formula (X-1) include: tert-butoxycarbonyl, 1-cyclopentylethoxycarbonyl, 1-cyclohexylethoxycarbonyl, 1-norbornylethoxycarbonyl, 1-phenylethoxycarbonyl, 1-(1-naphthyl)ethoxycarbonyl, 1-benzylethoxycarbonyl, 1-phenylethylethoxycarbonyl, etc.

Specific examples of acetal ester structures of carboxylic acids include: 1-methoxyethoxycarbonyl, 1-ethoxyethoxycarbonyl, 1-propoxyethoxycarbonyl, 1-butoxyethoxycarbonyl, 1-cyclohexyloxyethoxycarbonyl, 1-phenoxyethoxycarbonyl, 2-tetrahydrofuranyloxycarbonyl, 2-tetrahydropyranyloxycarbonyl, etc.

Specific examples of ketyl ester structures of carboxylic acids include: 1-methyl-1-methoxyethoxycarbonyl, 1-methyl-1-ethoxyethoxycarbonyl, 1-methyl-1-propoxyethoxycarbonyl, 1-methyl-1-butoxyethoxycarbonyl, 1-methyl-1-cyclohexyloxyethoxycarbonyl, 2-(2-methyltetrahydrofuranyl)oxycarbonyl, 2-(2-methyltetrahydropyranyl)oxycarbonyl, 1-methoxycyclopentyloxycarbonyl, 1-methoxycyclohexyloxycarbonyl, etc.

Structural unit U3 is preferably derived from a unit containing polymeric carbon-carbon unsaturated bonds and the radical "-COOR ⁵ ". Specifically, structural units represented by equations (7-1) to (7-3) below can be listed. [Chemistry 16] (In formulas (7-1) to (7-3), ^R41 , ^R42 , and ^R43 are each independently a hydrogen atom or a monovalent organic group. ^R44 is a hydrogen atom or a methyl group. ^Z2 is an oxygen atom or -NH-. ^X2 is a single bond or a divalent linker. ^R5 is a monovalent thermally deionizable group. m1 is 0 or 1.)

The content of structural unit U3 in polymer (P) is preferably 2 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, relative to all structural units constituting polymer (P). Furthermore, the content of structural unit U3 in polymer (P) is preferably 65 mol% or less, more preferably 60 mol% or less, relative to all structural units constituting polymer (P). If the content of structural unit U3 is within the aforementioned range, thermal decomposition of the polymer can be sufficiently suppressed during heating during film formation, and image retention is less likely to occur even when the thickness of the liquid crystal alignment film thins due to poor coating, etc., and long-term heat resistance improvement can be fully obtained. The polymer (P) may have only one type of structural unit U3, or it may have two or more types.

• The polymer (P) may also contain structural unit U4 derived from the group consisting of compounds selected from compounds represented by formula (8-1), compounds represented by formula (8-2), N-substituted aromatic maleimides, olefins, and (meth)acrylic acids that produce isocyanate groups by heating (excluding structural units U1, U2, and U3). By including structural unit U4 in the polymer (P), the thermal stability of the side chains can be further ensured, and the improvement effect on the long-term heat resistance of the obtained liquid crystal element can be further enhanced, which is preferable in the above respects. [Chemistry 17] (In formula (8-1), ^R18 is a hydrogen atom or a monovalent hydrocarbon with 1 to 10 carbon atoms. ^Ar1 is a divalent aromatic cycloalcohol. ^R19 is a hydrogen atom or a monovalent organic group. In formula (8-2), ^R6 is a monovalent substituent. t is an integer from 0 to 3. r is 0 or 1.)

Regarding the compound represented by formula (8-1), the aromatic ring group represented by Ar ¹ is a group formed by removing two hydrogen atoms from a substituted or unsubstituted aromatic ring. Examples of such aromatic rings include: aromatic hydrocarbon rings and aromatic nitrogen-containing heterocycles. Examples of aromatic hydrocarbon rings include: benzene rings, naphthalene rings, anthracene rings, etc. Examples of aromatic nitrogen-containing heterocycles include: pyridine rings, piperazine rings, etc. Examples of monovalent organic groups represented by R ¹⁹ include: monovalent hydrocarbons with 1 to 20 carbon atoms, monovalent organic groups with 6 to 30 carbon atoms having a liquid crystal atom structure, etc. R ¹⁸ is preferably a hydrogen atom, a monovalent hydrocarbon with 1 to 5 carbon atoms, or a phenyl group.

Specific examples of compounds represented by formula (8-1) include: styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 5-tert-butyl-2-methylstyrene, divinylbenzene, trivinylbenzene, tert-butoxystyrene, vinylbenzyl dimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-tert-butylstyrene, 3-tert-butylstyrene, 4-tert-butylstyrene, diphenylethylene, vinylnaphthalene, 4-vinylpyridine, and compounds represented by formulas (8-1-1) and (8-1-2) respectively. [Chem. 18] (In formulas (8-1-1) and (8-1-2), R ²⁰ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms.)

Examples of olefinic hydrocarbons include ethylene, propylene, butene, and pentene. Examples of compounds represented by formula (8-2) include norbornene and methyl norbornene.

N-substituted aromatic maleimine compounds are compounds in which the hydrogen atom bonded to the nitrogen atom in maleimine is replaced by a monovalent organic group having an aromatic ring. Examples of such aromatic rings include benzene rings and naphthalene rings, which may have substituents. Examples of substituents include alkyl groups having 1 to 10 carbon atoms, alkoxy groups having 1 to 10 carbon atoms, halogen atoms, carboxyl groups, etc.

Specific examples of N-substituted aromatic maleimide compounds include: N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(4-ethylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-benzylmaleimide, N-naphthylmaleimide, and N-(4-carboxyphenyl)maleimide.

Examples of (meth)acrylic acid compounds that produce isocyanate groups through heating include: the reaction product of (meth)acryloxyethyl isocyanate and diethyl malonate, the reaction product of (meth)acryloxyethyl isocyanate and 3,5-dimethylpyrazole, and the reaction product of (meth)acryloxyethyl isocyanate and methyl ethyl ketoxime.

The content of structural unit U4 in polymer (P) is preferably 1 mol% or more, more preferably 2 mol% or more, and even more preferably 5 mol% or more, relative to all structural units constituting polymer (P). Furthermore, the content of structural unit U4 in polymer (P) is preferably 50 mol% or less, more preferably 40 mol% or less, relative to all structural units constituting polymer (P). If the content of structural unit U4 is within the aforementioned range, long-term heat resistance is superior while maintaining good electrical properties, which is preferable in this respect. Polymer (P) may have only one type of structural unit U4, or it may have two or more types.

In addition to the above, polymer (P) may also contain structural units different from structural units U2 to U4 as other structural units. Examples of other structural units include: alkyl (meth)acrylates, (meth)acrylates having an alicyclic structure, (meth)acrylates having an aromatic ring structure, conjugated diene compounds, etc. The content of these structural units relative to all structural units constituting polymer (P) is preferably 30 mol% or less, more preferably 25 mol% or less.

(Synthesis of polymer (P)) Polymer (P) can be obtained by reacting a polymer containing a structural unit having a maleic anhydride structure with a primary or secondary amine having a partial structure represented by formula (5) as a reactive compound. More specifically, it can be manufactured by a method including the following step A. Step A: reacting polymer (x) with compound (y), said polymer (x) having a structural unit U5 derived from at least one compound (hereinafter also referred to as "anhydride-containing compound") selected from the group consisting of compounds represented by formula (11), formula (12), formula (13), and formula (14), said compound (y) being represented by formula (5) [Chemistry 19] (In formula (11), n is 0 or 1. In formulas (13) and (14), ^A1 is an elongated methyl group, an elongated ethyl group, a sulfur atom, or an oxygen atom. m is 1 or 2.) [Chemistry 20] (In formula (15), ^R1 is a hydrogen atom or a monovalent organic group with 1 or more carbon atoms. ^R2 is an alkyldiyl group. ^R3 is a monovalent organic group with 1 or more carbon atoms.)

• In the synthesis of polymer (x), by polymerizing monomers containing anhydride groups, polymers having a maleic anhydride structure can be obtained. Preferred examples of compounds containing anhydride groups include those represented by formulas (16-1) to (16-9). [Chemistry 21]

In terms of polymer (P) with a specified three-dimensional structure, which readily forms an amide ring through post-baking, thereby obtaining superior long-term heat resistance and side-chain structural stability, the anhydride-containing compound used in the synthesis of polymer (x) is particularly preferably the compound represented by formulas (16-1), (16-3) to (16-8). Furthermore, in the synthesis of polymer (x), one anhydride-containing compound may be used alone, or two or more may be used in combination.

• Compound (y) Compound (y) is preferably a primary or secondary amine having the aforementioned functional group. Specific examples of compound (y) include compounds represented by formulas (17-1) to (17-28) below. Furthermore, in the manufacture of polymer (P), compound (y) may be used alone or in combination of two or more. [Chemical 22] [Chemistry 23] [Chemistry 24] [Chemistry 25]

The synthesis method of polymer (x) is not particularly limited and can be carried out according to conventional organic chemistry methods. When polymer (x) is produced by free radical polymerization, the polymerization reaction is preferably carried out in an organic solvent in the presence of a polymerization initiator. Preferred polymerization initiators include, for example, azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile). The proportion of polymerization initiator used is preferably set at 0.01 to 30 parts by mass relative to 100 parts by mass of all monomers used in the reaction. Examples of organic solvents used include alcohols, ethers, ketones, amides, esters, and hydrocarbons.

In the polymerization reaction, the reaction temperature is preferably set to 30°C to 120°C, and the reaction time is preferably set to 1 hour to 36 hours. The amount of organic solvent used (a) is preferably set to be 0.1% to 60% by mass relative to the total amount of monomers used in the reaction (b) and the total amount of the reaction solution (a+b). The reaction solution obtained by dissolving the polymer can be separated by known separation methods, such as injecting the reaction solution into a large amount of unsuitable solvent and drying the precipitate obtained therefrom under reduced pressure, or removing the reaction solution by depressurized distillation using an evaporator.

In addition to being produced by free radical polymerization, polymer (x) can also be produced by known polymerization methods, such as ring-opening metathesis polymerization (ROMP) and polymerization using metallocene catalysts, depending on the type of monomer used.

The reaction between polymer (x) and compound (y) is preferably carried out in an organic solvent, in the presence of a catalyst if necessary. Examples of catalysts include pyridine derivatives such as N,N-dimethylaminopyridine and tertiary amines such as triethylamine, but are not limited to these. When using a catalyst, the proportion of catalyst used is preferably set to 0.01 molar equivalents to 0.5 molar equivalents relative to the total amount of structural units U5 possessed by polymer (x).

For a total of 100 mol of structural unit U5 in polymer (x), the proportion of compound (y) used is preferably 10 mol or more, more preferably 30 mol or more, and even more preferably 50 mol or more. Furthermore, for a total of 100 mol of structural unit U5 in polymer (x), the proportion of compound (y) used is preferably 200 mol or less, and even more preferably 150 mol or less. Moreover, compound (y) can be used alone or in combination with two or more compounds.

In the reaction, the organic solvent used may include, for example, alcohols, ethers, ketones, amides, esters, hydrocarbons, etc. The reaction temperature is preferably set to 30°C to 120°C, and the reaction time is preferably set to 1 hour to 24 hours. This yields a solution in which the polymer (P) is dissolved. The polymer (P) contained in this reaction solution can be separated using known separation methods and used in the preparation of liquid crystal alignment agents.

• Step B The polymer (P) can be a polymer produced by step A, or a polymer produced by a method that includes step B in addition to step A. By including the polymer produced by step B in the liquid crystal alignment agent, the structural stability of the side chains can be further improved, resulting in a liquid crystal element with superior long-term heat resistance; this is preferable in all respects. Step B: The step of reacting the reaction product of polymer (x) and compound (y) with an esterifying agent.

The esterifying agent is not particularly limited to any compound capable of esterifying a carboxyl group generated in the side chain through the reaction of polymer (x) and compound (y). In terms of efficient esterification, the esterifying agent preferably includes diazomethane, trimethylsilyl diazomethane, a mixture of boron trifluoride and an alcohol, a compound represented by formula (16), a compound represented by formula (17), or a compound represented by formula (18). [Chemistry 26] (In formula (16), ^R7 is a hydrogen atom or a methyl group. ^R8 and ^R9 are each independently a monovalent organic group. In formula (17), ^R10 to ^R12 are each independently a monovalent organic group. ^R13 is a hydrogen atom or a monovalent organic group. In formula (18), ^R14 , ^R15 and ^R16 are each independently a monovalent organic group. ^R17 is a hydrogen atom or a monovalent organic group.)

The monovalent organic groups represented by ^R8 and ^R9 in formula (16), ^R10 to ^R12 in formula (17), and ^R13 to ^R16 in formula (18) can be listed as: monovalent chain hydrocarbons, monovalent alicyclic hydrocarbons, groups in which any hydrogen atom of a monovalent chain hydrocarbon or alicyclic hydrocarbon is substituted by a hydroxyl or carboxyl group, groups in which any methyl group of a monovalent chain hydrocarbon or alicyclic hydrocarbon is substituted by a carbonyl, amide, urea, or carbamate bond, etc.

Specific examples of compounds represented by formulas (16) to (18) can be listed as compounds represented by formulas (20-1) to (20-5) respectively. [Chemistry 27]

The reaction product of polymer (x) and compound (y) with the esterifying agent is preferably carried out in an organic solvent. The organic solvent is preferably one capable of dissolving or dispersing the reaction product and the esterifying agent. The reaction temperature is preferably 0°C to 80°C, more preferably 10°C to 60°C. The reaction time is, for example, 30 minutes to 12 hours.

The weight-average molecular weight (Mw) of the polymer (P), as determined by gel permeation chromatography (GPC) based on polystyrene, is preferably 1,000 to 300,000, more preferably 2,000 to 100,000. 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 8 or less, more preferably 6 or less. Furthermore, the polymer (P) used in the preparation of the liquid crystal alignment agent may be a single type or a combination of two or more types.

The proportion of polymer (P) in the liquid crystal alignment agent is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 5% by mass or more, relative to the total amount of polymer components contained in the liquid crystal alignment agent. Furthermore, the proportion of polymer (P) in the liquid crystal alignment agent is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. One type of polymer (P) may be used alone, or two or more may be used in combination.

<Other Components> The liquid crystal alignment agent of this invention contains polymer (P) as described above, but may also contain other components besides polymer (P) if necessary.

(Polymer (Q)) From the viewpoint of further improving electrical properties or reliability, the liquid crystal alignment agent of the present invention preferably also contains a polymer (Q) different from polymer (P).

Examples of polymers (Q) include polyamide, polyimide, polyamide ester, polyamide, polyorganosiloxane, and polymers of monomers having unsaturated bonds. Among these, from the viewpoints of improved electrical properties, affinity with liquid crystals, mechanical strength, and affinity with polymer (P), polymer (Q) is particularly preferably at least one selected from the group consisting of polyamide, polyamide ester, and polyimide.

Regarding the amount of polymer (Q) contained in the liquid crystal alignment agent, from the viewpoint of balanced expression of the effects brought about by the formulation of polymer (Q) and the effects brought about by the formulation of polymer (P), it is preferable that the amount of polymer (P) is 100 parts by mass or more than 100 parts by mass of polymer (Q) used in the preparation of the liquid crystal alignment agent, more preferably the amount of polymer (P) is 100 parts by mass to 2000 parts by mass, and even more preferably the amount of polymer (P) is 200 parts by mass to 1500 parts by mass.

Polyamide, polyamide ester, and polyimide The polyamide, polyamide ester, and polyimide contained in the liquid crystal alignment agent can be synthesized according to existing known methods. For example, polyamide can be obtained by reacting a tetracarboxylic dianhydride with a diamine. Polyamide esters can be obtained, for example, by reacting the polyamide obtained above with an esterifying agent (e.g., methanol or ethanol, N,N-dimethylformamide diethyl acetal, etc.). Polyimide can be obtained, for example, by dehydrating and cyclizing the polyamide obtained above and then amide-imidizing it. Preferably, the amide-imidization rate of the polyimide is 20% to 95%, more preferably 30% to 90%. The amide ratio is expressed as a percentage, representing the proportion of amide ring structures relative to the total number of amide acid structures and amide ring structures in the polyimide.

There are no particular limitations on the tetracarboxylic dianhydrides used in the polymerization; various tetracarboxylic dianhydrides can be used. Specific examples include aliphatic tetracarboxylic dianhydrides such as butanetetracarboxylic dianhydride and ethylenediaminetetraacetic dianhydride; 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxylated cyclopentylacetic 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. c] Furan-1,3-dione, 2,4,6,8-tetracarboxylic bicyclic [3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, and other alicyclic tetracarboxylic dianhydrides; pyromellitic dianhydride, 4,4'-(hexafluoropyridineisopropyl)diphthalic anhydride, p-phenylbis(triphenylamine monoester anhydride), ethylene glycol bis(triphenylamine anhydride), 1,3-propanediol bis(triphenylamine anhydride), and other aromatic tetracarboxylic dianhydrides, etc. In addition, the tetracarboxylic dianhydrides described in Japanese Patent Application Publication No. 2010-97188 may be used. Furthermore, one tetracarboxylic dianhydride may be used alone, or two or more may be used in combination.

Examples of diamines used in polymerization include: aliphatic diamines such as ethylenediamine and tetramethylenediamine; alicyclic diamines such as p-cyclohexanediamine and 4,4'-epenylmethylbis(cyclohexylamine); and hexadecyloxydiaminobenzene, cholesteryloxydiaminobenzene, cholesteryl diaminobenzoate, cholesteryl diaminobenzoate, and lanosteryl diaminobenzoate. 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 2,5-diamino-N,N-diallylaniline, and isolaterally chained aromatic diamines represented by the compounds of formulas (2-1) to (2-4) below, respectively; [Chem. 28]

p-Phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylamine, 4-aminophenyl-4'-aminobenzoic acid ester, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,2-bis(4-aminophenoxy)ethane, 1,5-bis(4-aminophenoxy)pentane, bis[2-(4-aminophenyl)ethyl]adipic acid, bis(4-aminophenyl)amine, N,N-bis(4-aminophenyl)methylamine, N,N'-bis(4-aminophenyl)-benzidine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl Non-side-chain aromatic diamines such as benzene, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-(diaminophenylisopropyl)bisphenylamine, 1,4-bis(4-aminophenoxy)benzene, 4-(4-aminophenoxycarbonyl)-1-(4-aminophenyl)piperidine, and 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]diphenylamine; and diaminoorganosiloxanes such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, etc., may also be used. In addition, diamines described in Japanese Patent Application Publication No. 2010-97188 may be used. Furthermore, one diamine may be used alone, or two or more may be used in combination.

In addition to the above, other diamines used in the polymerization may include, for example, diamines containing photoalignment groups, diamines containing initiator groups, and nitrogen-containing diamines represented by formulas (19-1) to (19-10) respectively. [Chem. 29]

For the polyamide, polyamide ester, and polyimide contained in the liquid crystal alignment agent, the weight-average molecular weight (Mw) of polystyrene as determined by GPC is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. The molecular weight distribution (Mw/Mn) is preferably 7 or less, more preferably 5 or less. Furthermore, the polyamide, polyamide ester, and polyimide contained in the liquid crystal alignment agent may be only one type, or may be a combination of two or more types.

(Crosslinking Agent) The liquid crystal alignment agent of this invention may further contain a crosslinking agent. Examples of crosslinking agents include compounds having functional groups capable of reacting with functional groups (e.g., amino, carboxyl, epoxy, polymer unsaturated groups, etc.) possessed by the polymer (P) or other polymers. Specifically, examples of functional groups possessed by the crosslinking group include: cyclic ether groups, carboxyl groups, cyclic carbonate groups, alcoholic hydroxyl groups, β-hydroxylamine groups, amino groups, protected amino groups, protected isocyanate groups, trialkoxysilyl groups, polymeric unsaturated groups, maleimide groups, etc. The crosslinking agent preferably possesses two or more crosslinking groups, more preferably three or more, and even more preferably three to six.

When formulating a crosslinking agent, the content of the crosslinking agent in the liquid crystal alignment agent is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more, relative to 100 parts by mass of the total polymer component in the liquid crystal alignment agent. Furthermore, from the viewpoint of suppressing performance degradation caused by excessive addition, the content of the crosslinking agent is preferably 40 parts by mass or less, and more preferably 30 parts by mass or less, relative to 100 parts by mass of the total polymer component in the liquid crystal alignment agent. Moreover, one type of crosslinking agent can be used alone, or two or more types can be used in combination.

(Soluble) Liquid crystal alignment agents are typically prepared as liquid compositions, preferably dispersed or dissolved in a suitable solvent, consisting of a polymer (P) and other components as needed.

Organic solvents used include, for example: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolium ketone, γ-butyrolactone, γ-butyrolactamine, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol monomethyl ether, etc. Ethyl alcohol 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, ethyl carbonate, propyl carbonate, etc. They can be used alone or in combination of two or more.

Other components, besides those mentioned above, may include: low molecular weight compounds with a molecular weight of 1000 or less that have at least one epoxy group (e.g., ethylene glycol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylenediamine, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, etc.), functional silane compounds, polyfunctional (meth)acrylates, antioxidants, metal chelating compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, etc. The formulation ratios of other components may be appropriately selected based on the specific compounds, 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 total mass of the liquid crystal alignment agent) can be appropriately selected considering factors such as viscosity and volatility, and is preferably in the range of 1% to 10% by mass. That is, the liquid crystal alignment agent is coated onto the substrate surface as described later, preferably by heating, thereby forming a coating that serves as a liquid crystal alignment film or a coating that forms a liquid crystal alignment film. In this case, if the solid content concentration is 1% by mass or more, the film thickness can be sufficiently ensured, and a good liquid crystal alignment film can be easily obtained, which is preferable from this point of view. In addition, if the solid content concentration is less than 10% by mass, the film thickness will not become too large, and a good liquid crystal alignment film can be obtained. Furthermore, the viscosity of the liquid crystal alignment agent can be appropriately ensured, resulting in good coatability.

<<Liquid Crystal Alignment Film and Liquid Crystal Element>> The liquid crystal alignment film of the present invention can be formed from a liquid crystal alignment agent prepared as described above. Furthermore, the liquid crystal element of the present invention includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The operating mode of the liquid crystal in a liquid crystal element is not particularly limited. For example, it can be applied to various modes such as twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA) (including vertical alignment-multi-domain vertical alignment (VA-MVA) and vertical alignment-patterned vertical alignment (VA-PVA), in-plane switching (IPS), fringe field switching (FFS), and optically compensated bending (OCB). A liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, the substrate used varies depending on the desired operating mode. The action patterns in steps 2 and 3 are the same.

(Step 1: Coating Formation) First, a liquid crystal alignment agent is coated onto a substrate, preferably by heating the coated surface, thereby forming a coating on the substrate. 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. Conversely, in manufacturing IPS or FFS type liquid crystal elements, a substrate with electrodes comprising a patterned comb-shaped transparent conductive film or metal film, and an un-electrode substrate are used. For example, a film containing metals such as chromium can be used as the metal film. The coating of the liquid crystal alignment agent on the substrate is preferably performed on the electrode forming surface using offset printing, spin coating, roller coating, or inkjet printing.

After applying the liquid crystal alignment agent, it is preferable to preheat (pre-baking) to prevent sagging and other purposes. The pre-baking temperature is preferably 30°C to 150°C, more preferably 40°C to 120°C. The pre-baking time is preferably 0.25 minutes to 10 minutes.

Subsequently, a calcination (post-baking) step is performed to further remove the solvent and, if necessary, thermally amide-imide the amide structure present in the polymer. From the perspective of suppressing degradation such as fading caused by high temperatures during the formation of the liquid crystal alignment film on the color filter, and from the perspective of reducing environmental impact, the calcination temperature (post-baking temperature) at this time is preferably below 250°C, more preferably below 230°C, and even more preferably below 180°C. Furthermore, from the perspective of suppressing the reduction in liquid crystal alignment or reliability due to the influence of residual solvent components in the film, the post-baking temperature is preferably above 80°C, more preferably above 120°C. The post-baking time is preferably 5 minutes to 150 minutes. The thickness of the film formed in this way is preferably 0.001 μm to 1 μm. After the liquid crystal alignment agent is coated on the substrate, the organic solvent is removed, thereby forming a liquid crystal alignment film or a coating that becomes a liquid crystal alignment film.

(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 the like, 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.

The light irradiation in the photoalignment process can be performed by methods such as: irradiating the coating after the post-baking step; irradiating the coating after the pre-baking step and before the post-baking step; or irradiating the coating during the heating process in at least one of the pre-baking and post-baking steps. In the photoalignment process, the radiation used to irradiate 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. If the radiation is polarized, it can be linearly polarized or partially polarized. Furthermore, when using linearly polarized or partially polarized radiation, irradiation can be performed from a direction perpendicular to the substrate surface, from an inclined direction, or a combination of these. When irradiating unpolarized radiation, the irradiation direction is set to an inclined direction.

The light source used can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonant lamp, a xenon lamp, or an excimer laser. The radiation dose is preferably 400 J/ ^m² to 20,000 J/ ^m² , more preferably 1,000 J/ ^m² to 5,000 J/ ^m² . To improve reactivity, the coating can be heated while being irradiated with light. Additionally, the process may include contacting the light-treated organic membrane with water, a water-soluble organic solvent, or a mixture of water and a water-soluble organic solvent.

(Step 3: Construction of Liquid Crystal Cells) Prepare two substrates with liquid crystal alignment films formed as described above, and place liquid crystal between the two substrates facing each other to manufacture a liquid crystal cell. Examples of methods for manufacturing liquid crystal cells include: [1] placing two substrates facing each other with liquid crystal alignment films facing each other and a gap (spacer) between them, using a sealant to bond the peripheries of the two substrates, injecting liquid crystal to fill the cell gaps divided by the substrate surfaces and the sealant, and then sealing the injection holes; [2] applying a sealant to a designated area on one of the substrates with the liquid crystal alignment films formed, then dropping liquid crystal at several designated locations on the surface of the liquid crystal alignment films, bonding the other substrate with the liquid crystal alignment films facing each other, and allowing the liquid crystal to diffuse across the entire surface of the substrate (one-drop filling (ODF) method), etc. Preferably, the manufactured liquid crystal cells are further treated by heating them to the temperature at which the liquid crystal becomes an isotropic phase, followed by slow cooling to room temperature, thereby removing the flow alignment issues that occurred during liquid crystal filling.

As a sealant, for example, hardeners and epoxy resins containing alumina balls as spacers can be used. As spacers, photospacers, bead spacers, etc., can be used.

Examples of liquid crystals used include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred. Examples of nematic liquid crystals include Schiff base-based liquid crystals, azo-based liquid crystals, biphenyl-based liquid crystals, phenylcyclohexane-based liquid crystals, ester-based liquid crystals, terphenyl-based liquid crystals, biphenylcyclohexane-based liquid crystals, pyrimidine-based liquid crystals, dioxane-based liquid crystals, dicyclooctane-based liquid crystals, and cubane-based liquid crystals. Furthermore, substances such as cholesterol-type liquid crystals, chiral reagents, and ferroelectric liquid crystals can be added to these liquid crystals for further processing.

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, preferably 0.1 to 1 part by mass, relative to 100 parts by mass of the total liquid crystal.

Next, a polarizing plate is attached to the outer surface of the liquid crystal cell as needed. Examples of polarizing plates include those formed by sandwiching a polarizing film called an "H-film" with a cellulose acetate protective film, or polarizing plates containing an H-film themselves. The "H-film" is formed by extending and aligning polyvinyl alcohol while absorbing iodine. Thus, a liquid crystal element is obtained.

The liquid crystal element of this invention can be effectively applied to a variety of applications. Specifically, it can be used in clocks, portable game consoles, word processors, personal computers, car navigation systems, video recorders, personal digital assistants (PDAs), digital cameras, mobile phones, smartphones, various surveillance cameras, LCD televisions, information displays, and other display devices, or in dimming films. Furthermore, the liquid crystal element formed using the liquid crystal alignment agent of this invention can also be applied to optical films such as retardation films.

[Examples] The following examples provide specific illustrations, but the content of this invention is not limited to these examples.

In the following examples, the weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw/Mn) of the polymer were determined using the following methods. <Weight-average molecular weight, number-average molecular weight, and molecular weight distribution> Mw and Mn were determined by gel osmosis chromatography (GPC) under the following conditions. The molecular weight distribution (Mw/Mn) was calculated based on the obtained Mw and Mn values. Apparatus: Showa Denko (Co., Ltd.)'s "GPC-101" GPC Column: Combination of Shimadzu GLC (Co., Ltd.)'s "GPC-KF-801", "GPC-KF-802", "GPC-KF-803", and "GPC-KF-804" Mobile Phase: Tetrahydrofuran (THF) Column Temperature: 40℃ Flow Rate: 1.0 mL/min Sample Concentration: 1.0% by mass Sample Injection Volume: 100 μL Detector: Differential refractometer Standard Material: Monodisperse polystyrene

The compounds used in the examples below are shown below. In addition, for convenience, "the compound represented by formula (X)" will be simply referred to as "compound (X)".

(Reactive compound) [Chem. 30] [Chemistry 31]

(Monomers containing anhydride groups) [Chem. 32]

(Provide a unit for structural unit U2) [Chemistry 33]

(Provide a unit for structural unit U3) [Chemistry 34]

(Other units) [Chemistry 35]

(Tetracarboxylic acid dianhydride) [Chem. 36]

(Diamine) [Chem. 37] [Chemistry 38]

(Additive) [Chem. 39] [Chemistry 40]

<Synthesis of Monomers> [Synthetic Example 1-1: Synthesis of Compound (E-3)] Compound (E-3) was synthesized according to the following procedure. [Chemistry 41]

In a 500 ml three-necked flask equipped with a stirrer, 15.0 g of tert-butyl-4-(2-hydroxyethyl)benzylaminocarbamate, 12.0 g of 1-(4-fluorophenyl)-2-hydroxy-2-methylpropane-1-one, 9.1 g of potassium carbonate, and 300 mL of N,N-dimethylformamide were added. The mixture was stirred at room temperature for 30 minutes. After confirming that the raw materials were dissolved, the reaction was carried out at 80°C for 12 hours. After the reaction, the reaction solution was injected into 1500 ml of distilled water, and the precipitated solid was filtered off. Subsequently, the solid was vacuum dried and recrystallized to obtain 16.7 g of the intermediate. 100 ml of trifluoroacetic acid was added, and the mixture was stirred for 1 hour. The solution was then dissolved in a THF/ethyl acetate mixture. The solution was separated twice using sodium bicarbonate and three times using water. The organic layer was removed by solvent distillation and dried to obtain 10.5 g of compound (E-3).

[Synthetic Example 1-2: Synthesis of Compound (E-14)] Compound (E-14) was synthesized according to the following procedure. [Chemistry 42]

In Synthesis Example 1-1, tert-butyl (4-fluorobenzyl)aminocarbamate and 4-(4-pentylcyclohexyl)phenol were used instead of tert-butyl 4-(2-hydroxyethyl)benzylcarbamate and 1-(4-fluorophenyl)-2-hydroxy-2-methylpropane-1-one, respectively, and 9.7 g of compound (E-14) was obtained by the same method as in Synthesis Example 1-1. Furthermore, tert-butyl (4-fluorobenzyl)aminocarbamate was synthesized according to the method described in Tetrahedron, 2001, 57, 2965-2972.

[Synthetic Example 1-3: Synthesis of Compound (E-15)] Compound (E-15) was synthesized according to the following procedure. [Chemistry 43]

In a solution of (E)-3-(4-(4'-pentyl-[1,1'-bi(cyclohexane)]-4-yl)phenyl)acrylic acid, 200 ml of thionyl chloride and a catalyst amount of dimethylformamide (DMF) were added, and the mixture was reacted at 60°C for 2 hours. After the reaction, the thionyl chloride was removed by depressurized distillation. The resulting solid was dissolved in 20 ml of dehydrated THF to prepare solution A. Meanwhile, 13.2 g (82.0 mmol) of tert-butyl(2-hydroxyethyl)carbamate and 5.00 g of triethylamine were dissolved in 100 ml of dehydrated THF and cooled to 0°C in an ice bath. Solution A was added dropwise to this solution, and the mixture was reacted overnight at room temperature. After the reaction, the reaction solution was separated twice using hydrochloric acid at a concentration of 1 equivalence, and three times using water. The organic layer was removed by reduced-pressure distillation. This yielded the Boc protected intermediate. 100 ml of trifluoroacetic acid was added, and after stirring for 1 hour, the solution was dissolved in a THF/ethyl acetate mixture. The solution was then separated twice using sodium bicarbonate, and three times using water. The organic layer was removed by solvent distillation and dried to obtain compound (E-15).

[Synthetic Examples 1-4, 1-5: Synthesis of Compounds (E-16) and (E-17)] The intermediates of compounds (E-16) and (E-17) were synthesized according to the methods described in the following documents. In Synthetic Examples 1-3, the intermediates were used instead of (E)-3-(4-(4'-pentyl-[1,1'-bi(cyclohexane)]-4-yl)phenyl)acrylic acid; otherwise, compounds (E-16) and (E-17) were obtained by the same method as in Synthetic Examples 1-3. Intermediate for Compound (E-16): *Molecular Crystals and Liquid Crystals*, 2017, 650, 32-45 Intermediate for Compound (E-17): *Angewandte Chemie International Edition*, 2009, 48, 3494-3498

[Synthetic Examples 1-6: Synthesis of Compound (E-18)] [Chemistry 44]

200 ml of a dehydrated THF solution containing 30.2 g of triethyl phosphonoacetate was added dropwise to 4.8 g of sodium hydroxide and stirred at 0°C for 2 hours. Then, 100 ml of a THF solution containing 33.7 g of 4-acetylenol-4-( ₄ -cyanobutoxy)benzoate was added dropwise, and the mixture was stirred at room temperature for 1 hour, followed by reflux for 2 hours. After the reaction was complete, 300 ml of ethyl acetate was added, and the mixture was separated twice using saturated NH₄Cl solution and three times using water. The organic layer was removed by solvent distillation using a rotary evaporator, and then stirred under reflux for 3 hours with 300 ml of water and 10 g of sodium hydroxide. After stirring, the pH was adjusted to 4 using hydrochloric acid. The precipitated solid was filtered, washed with water, and dried to obtain 30.9 g of the intermediate. In Synthesis Examples 1-3, the intermediate was used instead of (E)-3-(4-(4'-pentyl-[1,1'-bi(cyclohexane)]-4-yl)phenyl)acrylic acid. Otherwise, compound (E-18) was obtained by the same method as in Synthesis Examples 1-3.

[Synthetic Examples 1-7: Synthesis of Compound (E-20)] Compound (E-20) was synthesized according to the following procedure. [Chemistry 45]

In a 500 ml three-necked flask equipped with a stirrer, add 10.0 g of 4-(4-pentylcyclohexyl)phenol, 9.8 g of 1-fluoro-4-nitrobenzene, 6.2 g of potassium carbonate, and 200 ml of N,N-dimethylformamide. Stir at room temperature for 30 minutes. After confirming that the raw materials are dissolved, react at 80°C for 12 hours. After the reaction, pour the reaction solution into 1500 ml of distilled water and filter out the precipitated solid. Then, vacuum dry the solid and recrystallize to obtain 15.2 g of the intermediate. Next, 12.0 g of the intermediate, 2.09 g of 5% palladium carbon, 60 ml of tetrahydrofuran, and 60 ml of ethanol were added to a 500 ml three-necked flask equipped with a stirrer, and the mixture was heated to 80 °C. 9.81 g of hydrazine monohydrate was then added dropwise, and the mixture was refluxed for 6 hours. After cooling to room temperature, the filtered solution was redetermined with 600 ml of water. The resulting solid was filtered, washed with water, and then vacuum dried to obtain 10.1 g of compound (E-20).

<Synthesis of Polymers> [Synthesis Example 2-1] Under nitrogen atmosphere, 20 mol of compound (A-1), 30 mol of compound (B-1), 10 mol of compound (B-2), 30 mol of compound (C-1), and 10 mol of compound (D-1) were added to a 100 mL two-necked flask as monomers; 2 mol of 2,2'-azobis(2,4-dimethylpentanones) relative to 100 mol of monomers was added as a free radical polymerization initiator; and 50 mL of tetrahydrofuran was added as a solvent. Polymerization was carried out at 70 °C for 6 hours. Furthermore, the total molar number of monomers was set to 50 mmol. After reprecipitation in n-hexane, the precipitate was filtered and vacuum-dried at room temperature for 8 hours to obtain the target polymer (P-1). The weight-average molecular weight (Mw), determined by GPC and converted to polystyrene, was 83,500, and the molecular weight distribution (Mw/Mn) was 4.26.

[Synthesis Examples 2-2 to 2-5, 2-10, and 2-11] The polymerizable monomers were set to the types and molar ratios shown in Table 1. Except for this, polymerization was carried out in the same manner as in Synthesis Example 2-1 to obtain polymers (P-2) to (P-5), (P-10), and (P-11) with the same weight-average molecular weight and molecular weight distribution as polymer (P-1). Furthermore, the total molar number of the polymerizable monomers was set to 50 mmol, as in Synthesis Example 2-1. The values in Table 1 represent the amount (molar%) of each monomer used in the synthesis of the polymers.

[Synthesis Example 2-6] Under nitrogen atmosphere, 50 moles of compound (A-4), 20 moles of compound (C-3), and 20 moles of compound (D-2) as monomers were added to a 100 ml two-necked flask; 50 ml of dichloromethane was added as a solvent; and 0.005 moles of a second-generation Grubbs catalyst was added as a polymerization catalyst. Polymerization was carried out at room temperature for 8 hours. The total mole count of the monomers was set to 20 mmol. 100 moles of butyl vinyl ether were added as a polymerization terminator. After stirring at room temperature for 30 minutes, the mixture was reprecipitated in n-hexane, filtered, and vacuum dried at room temperature for 8 hours to obtain the target polymer (P-6). The weight-average molecular weight (Mw), determined by GPC and converted to polystyrene, is 100-300, and the molecular weight distribution (Mw/Mn) is 2.35.

[Synthesis Examples 2-7] The monomers were set to the types and molar ratios shown in Table 1. Polymerization was carried out in the same manner as in Synthesis Examples 2-6, yielding a polymer (P-7) with the same weight-average molecular weight and molecular weight distribution as polymer (P-6). Furthermore, the total molar number of the monomers was set to 20 mmol, as in Synthesis Examples 2-6.

[Synthesis Example 2-8] Under nitrogen atmosphere, 70 moles of compound (A-6) and 30 moles of compound (B-4) as monomers were added to a 100 ml two-necked flask; 50 ml of toluene was added as a solvent; and 0.2 micromoles of bis(cyclopentadienyl)zirconia dichloride and 0.003 moles of methyl aluminoxane were added as polymerization catalysts. Polymerization was carried out at room temperature for 1 hour. The total mole count of the monomers was set to 50 mmol. After reprecipitation in acidic methanol solution, the precipitate was dissolved in NMP and reprecipitated again in acidic methanol solution. The polymer was then vacuum dried at room temperature for 8 hours to obtain the target polymer (P-8). The weight-average molecular weight (Mw), determined by GPC and converted to polystyrene, is 111,200, and the molecular weight distribution (Mw/Mn) is 3.12.

[Synthesis Examples 2-9] The monomers were set to the types and molar ratios shown in Table 1. Polymerization was carried out in the same manner as in Synthesis Examples 2-8 to obtain a polymer (P-9) with the same weight-average molecular weight and molecular weight distribution as polymer (P-8). Furthermore, the total molar number of the monomers was set to 50 mmol, as in Synthesis Examples 2-8.

[Table 1] polymer name Monomers containing anhydride groups Provides the unit of structural unit U2 Provides the unit U3 Other units A-1 A-2 A-3 A-4 A-5 A-6 A-7 B-1 B-2 B-3 B-4 C-1 C-2 C-3 D-1 D-2 D-3 D-4 D-5 D-6 D-7 D-8 Synthesis example 2-1 P-1 20 30 10 30 10 Synthesis example 2-2 P-2 30 30 10 10 10 10 Synthesis example 2-3 P-3 40 10 30 20 Synthesis example 2-4 P-4 50 25 25 Synthesis example 2-5 P-5 30 20 30 20 Synthesis example 2-6 P-6 50 20 30 Synthesis example 2-7 P-7 40 30 30 Synthesis example 2-8 P-8 70 30 Synthesis example 2-9 P-9 50 50 Synthesis example 2-10 P-10 30 30 20 10 10 Synthesis example 2-11 P-11 30 10 30 10 10 10

[Synthesis Example 3-1] To the polymer (P-1) obtained by Synthesis Example 2-1, 10 mol of compound (E-1) and 10 mol of compound (E-14) were added, relative to the total amount of monomers added. Then, 30 mol of dimethyl formamide-dimethyl acetal (DMF-DMA) was added as an esterifying agent, and the mixture was heated at 60°C for 3 hours. Subsequently, the resulting solution was reprecipitated with water to obtain the target polymer (P-12).

[Synthesis Examples 3-2 to 3-15] The polymer (base resin) reacting with the reactive compound and the reactive compound were set to the types and molar ratios shown in Table 2. Otherwise, polymerization was carried out in the same manner as in Synthesis Example 3-1, yielding polymers (P-13) to (P-26) with the same weight-average molecular weight and molecular weight distribution as polymer (P-12).

[Synthesis Examples 3-16 and 3-17] The polymer (base resin) and reactive compound used to react with the reactive compound were set to the types and molar ratios shown in Table 2. Esterification was not performed using an esterifying agent. Except as described above, polymerization was carried out in the same manner as in Synthesis Example 3-1, yielding polymers (P-27) and (P-28) with the same weight-average molecular weight and molecular weight distribution as polymer (P-12).

[Table 2] polymer name base resin Reactive compounds (mol%) Esterification E-1 E-2 E-3 E-4 E-5 E-6 E-7 E-8 E-9 E-10 E-11 E-12 E-13 E-14 E-15 E-16 E-17 E-18 E-19 E-20 Synthesis example 3-1 P-12 P-1 10 10 〇 Synthesis example 3-2 P-13 P-2 10 10 10 〇 Synthesis example 3-3 P-14 P-2 10 10 10 〇 Synthesis Example 3-4 P-15 P-2 10 10 10 〇 Synthesis Example 3-5 P-16 P-3 10 10 10 10 〇 Synthesis Example 3-6 P-17 P-4 10 20 20 〇 Synthesis Example 3-7 P-18 P-4 5 25 20 〇 Synthesis Example 3-8 P-19 P-5 20 10 〇 Synthesis Example 3-9 P-20 P-6 10 10 10 10 10 〇 Synthesis Example 3-10 P-21 P-7 10 20 10 〇 Synthesis example 3-11 P-22 P-8 10 30 10 20 〇 Synthesis example 3-12 P-23 P-9 10 30 10 〇 Synthesis example 3-13 P-24 P-9 20 20 10 〇 Synthesis example 3-14 P-25 P-2 10 20 〇 Synthesis example 3-15 P-26 P-10 10 10 10 〇 Synthesis example 3-16 P-27 P-2 10 10 10 Synthesis example 3-17 P-28 P-1 10 10

[Synthetic Example 4-1] 100 moles of compound (TA-1) as a tetracarboxylic dianhydride, 30 moles of compound (DA-1) as a diamine, 50 moles of compound (DA-8), and 20 moles of compound (DA-9) were dissolved in 170 g of N-methyl-2-pyrrolidone (NMP), and the reaction was carried out at 40°C for 24 hours to obtain a solution containing 20% by mass of polyacrylic acid. Subsequently, NMP was added to the obtained polyacrylic acid solution, along with pyridine and acetic anhydride, each in amounts of 1.80 moles equivalent relative to the carboxyl groups of the tetracarboxylic dianhydride derived from polyacrylic acid, and a dehydration and ring-closing reaction was carried out at 80°C for 4 hours. Following the dehydration and ring-closing reaction, the solvent in the system was replaced with fresh NMP, followed by concentration, to obtain a solution containing 15% by mass of polyimide (designated as polymer (PI-1)) with a acetylation rate of 70%. A small amount of this solution was aliquoted and NMP was added to prepare a 10% by mass solution, the viscosity of which was measured to be 43.7 mPa·s. Then, the obtained polymer solution was injected into a large amount of excess methanol to precipitate the reaction products. The precipitate was washed with methanol and dried under reduced pressure at 40°C for 15 hours to obtain polyimide (PI-1).

[Synthetic Examples 4-2, 4-3, 4-5 to 4-7] The types and amounts of tetracarboxylic dianhydrides and diamines used in the polymerization were changed as described in Table 3. Except for this, polymerization was carried out in the same manner as in Synthetic Example 4-1, yielding polymers (PI-2), (PI-3), (PI-5), to (PI-7) as polyimides. Furthermore, in Table 3, the values for tetracarboxylic dianhydrides represent the proportion (in mol) of each compound relative to 100 mol of the total amount of tetracarboxylic dianhydrides used in the synthesis. The values for diamines represent the proportion (in mol) of each compound relative to 100 mol of the total amount of diamines used in the synthesis.

[Synthesis Example 4-4] 100 moles of compound (TA-1) as a tetracarboxylic dianhydride, 30 moles of compound (DA-1) as a diamine, 50 moles of compound (DA-3), and 20 moles of compound (DA-9) as diamines were dissolved in 170 g of NMP and reacted at 60°C for 8 hours to obtain a solution containing 20% by mass of polyamide. The viscosity of the solution was 707 mPa·s.

[Synthesis Examples 4-8 and 4-9] The types and amounts of tetracarboxylic dianhydride and diamine used in the polymerization were changed as described in Table 3. Except for this, polymerization was carried out in the same manner as in Synthesis Example 4-4, yielding polymers (PI-8) and (PI-9) as polyamides, respectively.

[Table 3] polymer name Acid anhydride (mol%) Diamine (mol%) Enylimination rate (%) TA-1 TA-2 TA-3 TA-4 TA-5 DA-1 DA-2 DA-3 DA-4 DA-5 DA-6 DA-7 DA-8 DA-9 DA-10 DA-11 DA-12 Synthesis example 4-1 PI-1 100 30 50 20 70 Synthesis example 4-2 PI-2 70 30 30 10 30 30 65 Synthesis example 4-3 PI-3 40 30 30 30 30 30 10 63 Synthesis example 4-4 PI-4 100 30 50 20 - Synthesis Example 4-5 PI-5 50 30 20 30 10 50 10 69 Synthesis Example 4-6 PI-6 30 40 30 30 20 30 20 60 Synthesis Example 4-7 PI-7 50 50 50 20 30 65 Synthesis Example 4-8 PI-8 100 100 - Synthesis Example 4-9 PI-9 100 10 90 -

[Example 1: PSA-type liquid crystal display element] (1) Preparation of liquid crystal alignment agent (AL-1) 100 parts by mass of polymer (PI-1) obtained in Synthesis Example 4-1 were added to 10 parts by mass of polymer (P-12) obtained in Synthesis Example 3-1, along with NMP and butylcellosolve (BC) as solvents, to prepare a solution with a solvent composition of NMP/BC = 50/50 (mass ratio) and a solid content of 4.0% by mass. The solution was filtered using a filter with a pore size of 0.2 μm to prepare the liquid crystal alignment agent (AL-1).

(2) Preparation of the liquid crystal composition: 10 g of a nematic liquid crystal (Merck, MLC-6608) was mixed with 5% by mass of the liquid crystal compound represented by formula (L1-1) and 0.3% by mass of the photopolymerizable compound represented by formula (L2-1) to obtain the liquid crystal composition LC1. [Chemistry 46]

(3) The manufacturing of PSA type liquid crystal display elements uses a liquid crystal alignment film printing machine (manufactured by Nippon Shashin Printing Co., Ltd.) to coat the liquid crystal alignment agent (AL-1) prepared above onto the electrode surfaces of two glass substrates, each having a conductive film containing ITO electrodes patterned into a slit shape. After heating (pre-baking) on a heating plate at 80°C for 2 minutes to remove the solvent, it is heated (post-baking) on a heating plate at 230°C for 30 minutes to form a coating with an average film thickness of 100 nm. The coating is ultrasonically cleaned in ultrapure water for 1 minute and then dried in a clean oven at 100°C for 10 minutes to obtain a pair (two pieces) of substrates with liquid crystal alignment films. Furthermore, the electrode pattern used is the same type as the electrode pattern in the PSA mode. Next, an epoxy resin adhesive containing 5.5 μm diameter aluminum oxide spheres is applied to the outer edge of the surface of one of the substrates having the liquid crystal alignment film. The substrates are then overlapped and pressed together with the liquid crystal alignment film surfaces facing each other, allowing the adhesive to harden. Then, the liquid crystal assembly LC1 prepared above is filled between the two substrates through the liquid crystal injection port. The liquid crystal injection port is then sealed using an acrylic photocurable adhesive, thereby manufacturing a liquid crystal cell. Then, an AC 10 V at a frequency of 60 Hz is applied between the conductive films of the liquid crystal cell, and while the liquid crystal is driven, ultraviolet light is irradiated at an irradiation dose of 100,000 J/ ^m² using an ultraviolet irradiation device that uses 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. Then, polarizing plates are bonded to both outer surfaces of the substrate in such a manner that the polarization directions of the polarizing plates are orthogonal to each other and form a 45° angle with the projection direction of the ultraviolet light axis of the liquid crystal alignment film onto the substrate surface, thereby manufacturing a PSA-type liquid crystal display element.

(4) Evaluation of Electrical Characteristics Based on Voltage Holding Ratio (VHR) For the PSA-type liquid crystal display element manufactured above, a 5 V voltage was applied for a duration of 60 microseconds and a span of 167 milliseconds. The voltage holding ratio was then measured 167 milliseconds after the application was removed. The measuring device used was the VHR-1 manufactured by TOYO Technica (Co., Ltd.). A voltage holding ratio of 98% or higher was rated as "Good (○)", 95% or higher but less than 98% as "Acceptable (△)", and less than 95% as "Poor (×)". As a result, in this example, the electrical characteristics were evaluated as "Good (○)".

(5) Evaluation of electrical characteristics based on VHR after long baking In (3), the post-baking time was changed from 30 minutes to 1.5 hours. Except for this, the PSA-type liquid crystal display element was manufactured in the same manner as in (3). For the manufactured PSA-type liquid crystal display element, the voltage retention rate was measured under the same conditions as in (4). Here, a voltage retention rate of 95% or higher was set as "Good (○)", 90% or higher but less than 95% was set as "Acceptable (△)", and less than 90% was set as "Poor (×)". Furthermore, it can be said that the higher the VHR after long baking, the less likely impurities will be generated due to post-baking. As a result, in this example, the evaluation of the electrical characteristics after long baking was "Good (○)".

(6) Evaluation of long-term heat resistance No polarizing plates were attached to the outer two sides of the substrate. Except for this, the same operation as described in (3) was performed to manufacture PSA-type liquid crystal cells. For the PSA-type liquid crystal cells, the same operation as described in (4) was performed to measure the voltage retention rate. In addition, after the obtained liquid crystal cells were stored in a constant temperature bath at 100°C for 21 days (approximately 500 hours), the voltage retention rate was measured again. A rating of "Excellent (◎)" is assigned when the decrease in voltage retention rate caused by storage in a 100°C constant-temperature bath (voltage retention rate after liquid crystal unit manufacturing (%) - voltage retention rate after constant-temperature bath storage (%)) is less than 10%; "Good (○)" is assigned when it is 10% or more but less than 20%; "Acceptable (△)" is assigned when it is 20% or more but less than 40%; and "Poor (×)" is assigned when it is 40% or more. In this example, the rating is "Good (○)".

(7) Evaluation of AC image retention characteristics (thin film evaluation) In (3), the average film thickness of the coating is changed from 100 nm to 30 nm, and polarizing plates are not attached to the outer two sides of the substrate. Except for the above aspects, it is carried out in the same way as (3) to produce a PSA type liquid crystal cell. The liquid crystal cells fabricated were measured using a rotational crystallization method with a He-Ne laser, according to the methods described in "T.J. Scheffer et al., Journal of Applied Physics (J. Appl. Phys.), vol.48, p1783 (1977)" and "F. Nakano et al., Japanese Journal of Applied Physics (JPN. J. Appl. Phys.), vol.19, p2013 (1980)". The measurement was performed on the pre-tilt angle before voltage was applied to the liquid crystal unit (initial pre-tilt angle θini) and the pre-tilt angle after driving at AC 9 V and room temperature for 30 hours (post-drive pre-tilt angle θac). The pre-tilt angle change rate β[%] was calculated using the following formula (y). A pre-tilt angle change rate β of less than 3% was rated as "Good (○)", 3% or more but less than 5% was rated as "Acceptable (△)", and 5% or more was rated as "Poor (×)". Pre-tilt angle change rate β[%] = (θac - θini) / θini × 100 … (y)

[Examples 2-7, 9, 10, 15 and Comparative Examples 1-3] The formulation was changed as shown in Table 4. Except for this, liquid crystal alignment agents (AL-2), (AL-7), (AL-9), (AL-10), (AL-15), and (AL-18) were prepared using the same solvent composition and solid concentration as in Example 1. Furthermore, PSA-type liquid crystal display elements were manufactured using each liquid crystal alignment agent in the same manner as in Example 1, and various evaluations were performed. The evaluation results are shown in Table 4.

[Example 8: Vertically Oriented Liquid Crystal Display Element] (1) Preparation of Liquid Crystal Orienting Agent 100 parts by mass of polymer (PI-8) obtained in Synthesis Examples 4-8, 10 parts by mass of polymer (P-19) obtained in Synthesis Examples 3-8, 5 parts by mass of compound (Add-5), and NMP and BC as solvents were added to prepare a solution with a solvent composition of NMP/BC = 50/50 (mass ratio) and a solid content concentration of 4.0% by mass. The solution was filtered using a filter with a pore size of 0.2 μm to prepare the liquid crystal alignment agent (AL-8).

(2) Fabrication of the vertical-type liquid crystal display element: Using a rotary tool, the liquid crystal alignment agent (AL-8) prepared in (1) above is coated onto the transparent electrode surface of a glass substrate with a transparent electrode containing an ITO film. After pre-baking at 80°C for 1 minute, it is formally calcined at 200°C for 40 minutes to form a coating with a thickness of 0.08 μm. Then, at room temperature, the surface of the coating is irradiated with 200 J/ ^m² of polarized ultraviolet light containing bright lines of 313 nm from a direction inclined at 40° relative to the substrate normal using an Hg-Xe lamp and a glan-Taylor prism. The same operation is repeated to produce a pair (two pieces) of substrates with liquid crystal alignment films. On the outer periphery of the surface of one of the two substrates with a liquid crystal alignment film, an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres is applied by screen printing. The substrates are then pressed together with their liquid crystal alignment film surfaces facing each other, so that the projection directions of the ultraviolet rays irradiating each substrate onto the substrate surfaces are antiparallel. The adhesive is then thermo-cured at 150°C for 1 hour. Next, a liquid crystal assembly (Merck, MLC-6608) is filled into the gap between the substrates from the liquid crystal injection port. Finally, the liquid crystal injection port is sealed with an epoxy adhesive to obtain a liquid crystal cell. Furthermore, in order to remove the flow alignment during liquid crystal injection, the liquid crystal cell is heated at 150°C and then slowly cooled to room temperature. Next, polarizing plates are attached to the outer two sides of the substrate in the liquid crystal cell in such a way that their polarization directions are mutually orthogonal and at a 45° angle to the projection direction of the ultraviolet light irradiated during the formation of the liquid crystal alignment film on the substrate surface, thereby manufacturing a vertically aligned liquid crystal display element.

(3) Evaluation For the vertical-angle liquid crystal display element described in (2), the electrical characteristics based on voltage retention rate (VHR) were evaluated in the same manner as in Embodiment 1. Additionally, as in Embodiment 1, evaluations were performed on the electrical characteristics based on VHR after long-term baking, long-term heat resistance, and AC retention characteristics (thin-film evaluation). The evaluation results are shown in Table 4.

[Examples 11-13] The formulation was changed as shown in Table 4. Except for this, liquid crystal alignment agents (AL-11) to (AL-13) were prepared using the same solvent composition and solid concentration as in Example 8. Furthermore, using each liquid crystal alignment agent, a vertical-angle liquid crystal display element and a vertical-angle liquid crystal cell were manufactured in the same manner as in Example 8, and various evaluations were performed. The evaluation results are shown in Table 4.

[Example 14: Optically Oriented FFS Type Liquid Crystal Display Element] (1) Preparation of Liquid Crystal Orienting Agent (AL-14) 100 parts by mass of polymer (PI-8) obtained in Synthesis Examples 4-8 were mixed with 10 parts by mass of polymer (P-25) obtained in Synthesis Examples 3-14, 5 parts by mass of compound (Add-9), and NMP and BC as solvents to prepare a solution with a solvent composition of NMP/BC = 50/50 (mass ratio) and a solid content of 4.0% by mass. The solution was filtered using a filter with a pore size of 0.2 μm to prepare the liquid crystal orientation agent (AL-14).

(2) Preparation for manufacturing an FFS type liquid crystal display element: A glass substrate (designated as the first substrate) having a flat plate electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) sequentially laminated on one side, and a glass substrate without electrodes (designated as the second substrate). Then, a liquid crystal alignment agent (AL-14) 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 heating plate at 80°C. Afterward, it is dried (post-baked) for 30 minutes in an oven at 230°C where nitrogen replacement has been performed inside the chamber, thereby forming a coating with an average film thickness of 0.1 μm. Photoalignment treatment was performed by irradiating the obtained coating with 1,000 J/ ^m² of ultraviolet light, including linearly polarized 254 nm bright line, from the normal direction of the substrate using an Hg-Xe lamp. The irradiation amount was measured using a photometer with a wavelength of 254 nm as the reference. Next, the photoaligned coating was heat-treated by heating it in a clean oven at 230°C for 30 minutes to form a liquid crystal alignment film. Then, for one of the pair of 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 on one of the substrates. Subsequently, the substrates were overlapped and pressed together so that the projection direction of the polarization axis on the substrate surface during light irradiation was antiparallel, and the adhesive was thermosetting at 150°C for 1 hour. Next, negative liquid crystal (manufactured by Merck, MLC-6608) was filled between a pair of substrates through the liquid crystal injection port, and the liquid crystal injection port was sealed using an epoxy adhesive to obtain a liquid crystal cell. Then, to remove the flow alignment during liquid crystal injection, it was heated at 120°C and slowly cooled to room temperature. Finally, a polarizing plate was attached to the outer two sides of the substrate of the liquid crystal cell to obtain a liquid crystal display element. In addition, the series of operations were performed by varying the UV irradiation amount after baking within the range of 100 J/ ^m² to 10,000 J/ ^m² , thereby producing three or more liquid crystal display elements with different UV irradiation amounts. The liquid crystal display element with the exposure amount (optimal exposure amount) that shows the best alignment characteristics was used for the following evaluation.

(3) Evaluation For the optical FFS type liquid crystal display element described in (2), the electrical characteristics based on voltage retention rate (VHR), the electrical characteristics based on VHR after long-term baking, and the long-term heat resistance were evaluated in the same manner as in Embodiment 1. In addition, the AC retention characteristics (thin film evaluation) were evaluated according to the following procedure. The evaluation results are shown in Table 4.

• Evaluation of AC Residual Characteristics of Optical FFS Type Liquid Crystal Cells (Thin Film Evaluation) In (2), the average film thickness of the coating was changed from 100 nm to 30 nm, and polarizing plates were not attached to the outer two sides of the substrate. Except for the above aspects, optical FFS type liquid crystal cells were fabricated in the same manner as in (2). After driving the fabricated optical FFS type liquid crystal cell with an AC voltage of 10 V for 30 hours, the black brightness change rate (%) expressed by the following formula (b) was measured using a device with a polarizer and an analyzer arranged between the light source and the light intensity detector. Black brightness change rate (%) = [(β(30 hr) - β(0)) / β(0)] × 100 … (b) (In formula (b), β(0) is the minimum light transmittance of the liquid crystal display element before the driving stress is sandwiched between the polarizer and the analyzer under crossed Nicol, and β(30 hr) is the minimum light transmittance of the liquid crystal display element after 30 hours of driving under crossed Nicol, sandwiched between the polarizer and the analyzer.) AC image retention characteristics are expressed by the change rate of black level before 30 hours of driving with AC voltage and the change rate of black level after 30 hours of driving with AC voltage. It can be said that the smaller the change rate, the better the AC image retention characteristics. Liquid crystal display elements with a black luminance variation rate of less than 10% are designated as "Good (○)", those with a rate of 10% or more but less than 30% are designated as "Acceptable (△)", and those with a rate of 30% or more are designated as "Poor (×)". As a result, the black luminance variation rate of the liquid crystal display element is 5%, and the AC image retention characteristic is judged as "Good (○)".

[Table 4] Liquid crystal alignment agent Evaluation Orientation agent name craftsmanship Polymer 1 Polymer 2 Additives Typically VHR Long baking time VHR Long-term heat resistance AC afterimage (film) Kind Number of portions Kind Number of portions Kind Number of portions Implementation Example 1 AL-1 PSA P-12 10 PI-1 100 〇 〇 〇 〇 Implementation Example 2 AL-2 PSA P-13 10 PI-1 100 〇 〇 ◎ 〇 Implementation Example 3 AL-3 PSA P-14 10 PI-1 100 Add-3 5 〇 〇 ◎ 〇 Implementation Example 4 AL-4 PSA P-15 20 PI-2 100 〇 〇 ◎ 〇 Implementation Example 5 AL-5 PSA P-16 10 PI-3 100 Add-2 10 〇 〇 〇 〇 Implementation Example 6 AL-6 PSA P-17 10 PI-4 100 Add-1 10 〇 〇 ◎ 〇 Implementation Example 7 AL-7 PSA P-18 10 PI-5 100 Add-7 5 〇 〇 ◎ 〇 Implementation Example 8 AL-8 Light VA P-19 10 PI-8 100 Add-5 5 〇 〇 〇 〇 Implementation Example 9 AL-9 PSA P-20 10 PI-6 100 Add-6 5 〇 〇 ◎ 〇 Implementation Example 10 AL-10 PSA P-21 10 PI-7 100 Add-5/Add-7 5/5 〇 〇 ◎ 〇 Implementation Example 11 AL-11 Light VA P-22 10 PI-8 100 Add-4 5 〇 〇 ◎ 〇 Implementation Example 12 AL-12 Light VA P-23 10 PI-8 100 〇 〇 ◎ 〇 Implementation Example 13 AL-13 Light VA P-24 10 PI-9 100 Add-8 5 〇 〇 ◎ 〇 Implementation Example 14 AL-14 Light FFS P-25 10 PI-8 100 Add-9 5 〇 〇 ◎ 〇 Implementation Example 15 AL-15 PSA P-26 10 PI-1 100 〇 〇 ◎ 〇 Implementation Example 16 AL-16 PSA P-27 10 PI-1 100 〇 〇 ◎ △ Comparative example 1 AL-17 PSA P-28 10 PI-1 100 〇 △ △ △ Comparative example 2 AL-18 PSA P-11 10 PI-1 100 〇 △ × ×

As can be seen from the results of the above embodiments, the liquid crystal alignment agents of Examples 1 to 16, which contain polymer (P), have good or excellent evaluations of voltage retention and long-term heat resistance after long-term baking. Furthermore, the AC image retention characteristics of the liquid crystal alignment agents of Examples 1 to 16 have good or acceptable evaluations. In particular, the AC image retention characteristics of Examples 1 to 15, which contain polymer (P) that has undergone esterification treatment, are excellent and superior.

In contrast, in Comparative Examples 1 and 2, which do not contain polymer (P), the voltage retention rate and long-term heat resistance of the liquid crystal alignment agent of Comparative Example 1 after long-term baking were rated as acceptable (△). However, the long-term heat resistance and AC retention characteristics of the liquid crystal alignment agent of Comparative Example 2 were rated as poor (×), indicating that its performance was worse than that of Examples 1 to 16. Furthermore, in Comparative Example 2, a polymer (P-11) synthesized using compounds (D-3) and (D-4), which are ring-opening forms of maleimide compounds, was used as the polymer component of the liquid crystal alignment agent. In the polymer (P-11), the two groups that form carbon-carbon double bonds with compounds (D-3) and (D-4) adopt an inverse structure, making it difficult to close the ring during post-baking. Therefore, it is inferred that the voltage retention rate, long-term heat resistance and AC residue evaluation after long-term baking are worse than those of Examples 1 to 16.

without

without.

Claims (11)

A liquid crystal alignment agent comprising a polymer (P) having at least one of the following structural units selected from the group consisting of structural units represented by formula (1), formula (2), formula (3), formula (4), and formula (5). In formulas (1) to (5), one of ^X1 and ^X2 is a monovalent group represented by formula (6) below, and the other is ^-OR4 ; ^R4 is a hydrogen atom or a monovalent organic group with more than 1 carbon atom; ^A1 is an methyl group, an ethyl group, a sulfur atom, or an oxygen atom; m is 1 or 2; "*1" represents a bond bond with the atomic bonds that constitute the main chain of the polymer; In formula (6), ^R1 is a hydrogen atom or a monovalent organic group with more than 1 carbon atom; ^R2 is an alkyldiyl group; ^R3 is a monovalent organic group with more than 1 carbon atom; "*" indicates a bond. The liquid crystal alignment agent as claimed in claim 1, wherein ^R3 has at least one selected from the group consisting of an alkaline group, a group that generates an alkaline group by heating, an acidic group, a group that generates an acidic group by heating, a crosslinking group, a group that generates a crosslinking group by heating, a photoaligning group, a vertical alignment group, a photoinitiator group, an electron transporting group, and a hole transporting group. The liquid crystal alignment agent as described in claim 1 or claim 2, wherein the polymer (P) comprises structural units having a cyclic carbonate structure. The liquid crystal alignment agent as described in claim 1 or claim 2, wherein the polymer (P) comprises a structural unit having -COOR ⁵ , wherein R ⁵ is a monovalent thermally deionizable group. The liquid crystal alignment agent as described in claim 1 or claim 2, wherein the polymer (P) comprises structural units derived from the group consisting of compounds selected from compounds represented by formula (8-1), compounds represented by formula (8-2), N-substituted aromatic maleimides, olefinic hydrocarbons, and (meth)acrylic acid compounds that generate isocyanate groups by heating. In formula (8-1), R ¹⁸ is a hydrogen atom or a monovalent hydrocarbon with 1 to 10 carbon atoms; Ar ¹ is a divalent aromatic cycloalcohol; R ¹⁹ is a hydrogen atom or a monovalent organic group; in formula (8-2), R ⁶ is a monovalent substituent; t is an integer from 0 to 3; r is 0 or 1. The liquid crystal alignment agent as described in claim 1 or claim 2 further comprises at least one polymer selected from the group consisting of polyamide, polyamide ester and polyimide. A liquid crystal alignment film formed using a liquid crystal alignment agent as described in any one of claims 1 to 6. A liquid crystal element comprising a liquid crystal alignment film as described in claim 7. An aggregate having at least one of the following structural units selected from the group consisting of structural units represented by equation (1), equation (2), equation (3), equation (4), and equation (5). In formulas (1) to (5), one of ^X1 and ^X2 is a monovalent group represented by formula (6) below, and the other is ^-OR4 ; ^R4 is a hydrogen atom or a monovalent organic group with more than 1 carbon atom; ^A1 is an methyl group, an ethyl group, a sulfur atom, or an oxygen atom; m is 1 or 2; "*1" represents a bond bond with the atomic bonds that constitute the main chain of the polymer; In formula (6), ^R1 is a hydrogen atom or a monovalent organic group with more than 1 carbon atom; ^R2 is an alkyldiyl group; ^R3 is a monovalent organic group with more than 1 carbon atom; "*" indicates a bond. A method for manufacturing a polymer includes: a step of reacting a polymer (x) with a compound (y), said polymer (x) having a structural unit derived from at least one compound selected from the group consisting of a compound represented by formula (11), a compound represented by formula (12), a compound represented by formula (13), and a compound represented by formula (14), said compound (y) being represented by formula (15); and a step of reacting the reaction product of said polymer (x) and said compound (y) with an esterifying agent. In formula (11), n is 0 or 1; in formulas (13) and (14), ^A1 is a methyl group, an ethyl group, a sulfur atom or an oxygen atom; m is 1 or 2; In formula (15), ^R1 is a hydrogen atom or a monovalent organic group with more than 1 carbon atom; ^R2 is an alkyldiyl group; and ^R3 is a monovalent organic group with more than 1 carbon atom. The method for manufacturing the polymer as described in claim 10, wherein the esterifying agent is a mixture of diazomethane, trimethylsilyl diazomethane, boron trifluoride and an alcohol, a compound represented by formula (16) below, a compound represented by formula (17) below, or a compound represented by formula (18) below. In formula (16), ^R7 is a hydrogen atom or a methyl group; ^R8 and ^R9 are each independently a monovalent organic group; in formula (17), ^R10 to ^R12 are each independently a monovalent organic group; ^R13 is a hydrogen atom or a monovalent organic group; in formula (18), ^R14 , ^R15 and ^R16 are each independently a monovalent organic group; ^R17 is a hydrogen atom or a monovalent organic group.