Liquid crystal alignment agent, liquid crystal alignment film, liquid crystal element, and polymer

Abstract

The present application provides a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal element, and a polymer and a manufacturing method thereof, which are highly reliable in terms of heat resistance, and can form a liquid crystal alignment film that exhibits good liquid crystal alignment even in a case where the film thickness of the liquid crystal alignment film is thinned due to coating failure or the like. The present application contains a polymer (P) in the liquid crystal alignment agent, the polymer (P) having at least one selected from the group consisting of structural units represented by formulae (1) to (5). In formulae (1) to (5), one of X 1 and X 2 is a monovalent group represented by formula (6), and the other is -OR 4 . R 4 is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. A 1 is a methylene group, an ethylene group, a sulfur atom, or an oxygen atom. In formula (6), R 1 is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. R 2 is an alkanediyl group. R 3 is a monovalent organic group having 1 or more carbon atoms.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal element, and a polymer and a method for producing the same. BACKGROUND

[0002] As a polymer component of a liquid crystal alignment film, a polyimide is generally used for the reason of heat resistance and the like. On the other hand, the polyimide has low solubility to a solvent, and thus it is considered that, in a case where a large hydrophobic group (mesogen structure or the like) is introduced to a side chain of a polymer, the solubility is insufficient, and the coatability is reduced. Thus, it is proposed to use an acrylic polymer or a styrene-maleimide polymer instead of a polyimide as a material of a liquid crystal alignment film (for example, refer to Patent Literature 1).

[0003] [Patent Literature]

[0004] [Patent Literature]

[0005] [Patent Literature 1] International Publication No. 2018 / 074547 SUMMARY

[0006] [Problems to be Solved by the Invention]

[0007] A liquid crystal element is applied to a wide range of uses from a liquid crystal television to a small display device such as a smartphone or a tablet personal computer (PC). Along with such multi-use, it is assumed that a liquid crystal element is driven for a longer time than ever before, and is used under a more severe temperature condition. Further, along with high definition of a liquid crystal element, higher coating uniformity is required, and a liquid crystal alignment film that can stably exhibit good liquid crystal alignment even in a case where a film becomes thin due to coating failure or the like is required.

[0008] A liquid crystal alignment film is generally formed on a substrate by coating a liquid crystal alignment agent in which a polymer component is dissolved or dispersed in a solvent on the substrate, and heating at a high temperature (for example, 200°C to 250°C). On the other hand, in a case where the heat resistance of the polymer component is insufficient, the polymer component is thermally decomposed due to a heating treatment at the time of film formation, and the component generated by the thermal decomposition becomes an impurity, and thus there is a concern that the reliability is reduced. From the viewpoint of further high quality in recent years, for a liquid crystal alignment agent, it is required that the decomposition product formed due to heating at the time of film formation is small, and in addition, the performance can be maintained even in a case where a liquid crystal element is driven for a long time, that is, the reliability with respect to heat resistance is high, and a liquid crystal alignment film that exhibits good liquid crystal alignment even in a case where a film thickness is reduced due to coating failure or the like can be formed.

[0009] The present application was made in view of the above circumstances, and a main object thereof is to provide a liquid crystal alignment agent which is high in reliability with respect to heat resistance, and can form a liquid crystal alignment film which is excellent in liquid crystal alignment property even in a case where the film thickness of the liquid crystal alignment film is thinned due to coating failure or the like.

[0010] [Technical means for solving the problem]

[0011] The present inventors and others have focused on introducing the following structure to the polymeric component of a liquid crystal alignment agent: the structure is converted into a closed ring structure which is high in heat resistance by heating at the time of film formation, and the conversion rate to the closed ring structure is high, and the reverse reaction is less likely to occur. Specifically, the present application employs the following means in order to solve the above problem.

[0012] [1] A liquid crystal alignment agent comprising a polymer (P) having at least one selected from the group consisting of a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), a structural unit represented by the following formula (4), and a structural unit represented by the following formula (5).

[0013] [Chemical Formula 1]

[0014]

[0015] (In formulae (1) to (5), X 1 and X 2 are one monovalent group represented by the following formula (6), and the other is -OR 4 . R 4 is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. A 1 is a methylene group, an ethylene group, a sulfur atom, or an oxygen atom. m is 1 or 2. "*1" indicates a bonding bond to an atom constituting the main chain of the polymer.)

[0016] [Chemical Formula 2]

[0017] *-NR 1 -R 2 -R 3 (6)

[0018] (In formula (6), R 1 is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. R 2 is an alkanediyl group. R 3 is a monovalent organic group having 1 or more carbon atoms. "*" indicates a bonding bond.)

[0019] [2] A liquid crystal alignment film formed using the liquid crystal alignment agent according to the above [1].

[0020] [3] A liquid crystal element comprising the liquid crystal alignment film according to the [2].

[0021] [4] A polymer having at least one selected from the group consisting of a structural unit represented by the formula (1), a structural unit represented by the formula (2), a structural unit represented by the formula (3), a structural unit represented by the formula (4), and a structural unit represented by the formula (5).

[0022] [5] A method for producing a polymer, comprising: a step of reacting a polymer (x) having a structural unit derived from at least one compound selected from the group consisting of a compound represented by the following formula (11), a compound represented by the following formula (12), a compound represented by the following formula (13), and a compound represented by the following formula (14), with a compound (y) represented by the following formula (15); and a step of reacting a reaction product of the polymer (x) and the compound (y) with an esterification agent.

[0023] [Chemical 3]

[0024]

[0025] (In the formula (11), n is 0 or 1. In the formula (13) and the formula (14), A 1 is a methylene group, an ethylene group, a sulfur atom, or an oxygen atom. m is 1 or 2.)

[0026] [Chemical 4]

[0027]

[0028] (In the formula (15), R 1 is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. R 2 is an alkanediyl group. R 3 is a monovalent organic group having 1 or more carbon atoms.)

[0029] [Effects of the Invention]

[0030] According to the liquid crystal alignment agent containing the polymer (P), reliability with respect to heat resistance is high, and a liquid crystal alignment film that stably exhibits good liquid crystal alignment properties even in a case where the film thickness of the liquid crystal alignment film is thinned due to coating failure or the like can be formed. DETAILED DESCRIPTION

[0031] Hereinafter, matters related to the modality of the present disclosure are described in detail. In addition, in the present specification, the so-called "hydrocarbon group" is a meaning including a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The so-called "chain hydrocarbon group" refers to a straight-chain hydrocarbon group and a branched-chain hydrocarbon group which do not contain a cyclic structure, but are composed of only a chain structure. Among them, it can be either saturated or unsaturated. The so-called "alicyclic hydrocarbon group" refers to a hydrocarbon group which contains only an alicyclic hydrocarbon structure as a ring structure, and does not contain an aromatic ring structure. Among them, it does not need to be composed of only an alicyclic hydrocarbon structure, and a group having a chain structure in a part thereof is also included. The so-called "aromatic hydrocarbon group" refers to a hydrocarbon group which contains an aromatic ring structure as a ring structure. Among them, it does not need to be composed of only an aromatic ring structure, and a chain structure or an alicyclic hydrocarbon structure can be included in a part thereof. The so-called "main chain" of a polymer refers to a portion of the "main stem" which is the longest in the atomic chain of the polymer. The so-called "side chain" of a polymer refers to a portion which branches from the "main stem" of the polymer. The so-called "organic group" refers to an atomic group obtained by removing an arbitrary hydrogen atom from a compound containing carbon (i.e., an organic compound).

[0032] <<Liquid crystal alignment agent>>

[0033] The liquid crystal alignment agent of the present disclosure contains the following polymer (P).

[0034] Polymer (P): a polymer having at least one structural unit selected from the group consisting of a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), a structural unit represented by the following formula (4), and a structural unit represented by the following formula (5) (hereinafter, also referred to as "structural unit U1")

[0035] [Chemical Formula 5]

[0036]

[0037] (In formulae (1) to (5), X 1 and X 2 one of them is a monovalent group represented by the following formula (6), and the other is -OR 4 . R 4 is a hydrogen atom or a monovalent organic group having a carbon number of 1 or more. A 1 is a methylene group, an ethylene group, a sulfur atom, or an oxygen atom. m is 1 or 2. "*1" indicates a bonding bond to an atom constituting the main chain of the polymer.)

[0038] [Chemical Formula 6]

[0039] *-NR 1 -R 2 -R 3 (6)

[0040] (In the formula (6), R 1 is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. R 2 is an alkanediyl group. R 3 is a monovalent organic group having 1 or more carbon atoms. "*" represents a bond.)

[0041] Hereinafter, each component contained in the liquid crystal alignment agent of the present disclosure, and other components which are optionally arbitrarily blended, are described.

[0042] <Polymer (P)>

[0043] (structural unit U1)

[0044] In the formulae (1) to (5), X 1 and X 2 are one of the monovalent groups represented by the formula (6). In the formula (6), R 1 the monovalent organic group having 1 or more carbon atoms represented by R 1 is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, more preferably an alkyl group or a phenyl group having 1 to 6 carbon atoms, and further preferably an alkyl group having 1 to 3 carbon atoms. Among them, the group represented by R 2 is preferably a hydrogen atom or a methyl group.

[0045] R 2 the alkanediyl group represented by R 2 is preferably a linear alkanediyl group having 1 to 5 carbon atoms, more preferably a linear alkanediyl group having 1 to 3 carbon atoms, and further preferably a methylene group or an ethylene group.

[0046] As the monovalent organic group represented by R 3 , a monovalent hydrocarbon group having 1 to 20 carbon atoms; a monovalent hydrocarbon group in which any methylene group is substituted by one or more selected from the group consisting of -O-, -S-, -CO-, -COO-, -NR 10 -, -NR 10 -CO-, -NR 10 -COO-, and -N=N- (hereinafter, also referred to as "monovalent group R E "); a monovalent group having 1 to 20 carbon atoms in which any hydrogen atom of a hydrocarbon group or a monovalent group R E is substituted by a fluorine atom, a hydroxyl group, a cyano group, a carboxyl group, or the like; a monovalent group having a heterocycle; and the like can be exemplified. R 10R represents a hydrogen atom or a monovalent organic group. As R 10 The monovalent organic group represented by R is exemplified by an alkyl group having a carbon number of 1 to 6, a phenyl group, a tert-butoxycarbonyl group, a hydroxyalkyl group, and the like.

[0047] R 3 The monovalent organic group represented by R is particularly preferably a group containing 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 photo-orientation group, a vertical orientation group, a photoinitiator group, an electron-transporting group, and a hole-transporting group.

[0048] • a basic group and a group that generates a basic group by heating

[0049] In the case where the monovalent organic group represented by R 3 In the case where the monovalent organic group represented by R has a basic group and a group that generates a basic group by heating, as the basic group, a nitrogen-containing group is exemplified. As specific examples of the nitrogen-containing group, a primary amino group, a secondary amino group, a tertiary amino group, and a nitrogen-containing heterocyclic group, and the like are exemplified. As R 3 Specific examples of the case where the monovalent organic group represented by R has a basic group and a group that generates a basic group by heating are exemplified by the groups represented by the following Formulas (r1-1) to (r1-4), respectively.

[0050] [Chemical Formula 7]

[0051]

[0052] (In Formulas (r1-1) to (r1-4), PG is a monovalent thermally dissociable group. "*" represents a bond.)

[0053] The group represented by the Formula (r1-2) dissociates the group PG by heating, thereby generating a basic group. From the viewpoint of achieving simplification of the process by dissociating the group PG during the process of forming a liquid crystal alignment film by coating a liquid crystal aligning agent on a substrate and heating, the group PG is preferably a group that decomposes at a temperature of 120°C to 300°C and is substituted to a hydrogen atom. Specifically, a tert-butoxycarbonyl group (Boc group) or a 9-fluorenylmethoxycarbonyl group is preferred, and a tert-butoxycarbonyl group is particularly preferred.

[0054] • an acidic group and a group that generates an acidic group by heating

[0055] In the case where the monovalent organic group represented by R 3 In the case where the monovalent organic group represented by R has an acidic group and a group that generates an acidic group by heating, as the acidic group, a carboxylic acid group, a phosphoric acid group, a phosphorous acid group, a sulfonic acid group, and an amido acid group, and the like are exemplified. Among them, R 3 The acidic group preferably has a carboxylic acid group or an amido acid group. As R3 Preferred specific examples of the monovalent organic group represented by the formula (r2-1) to formula (r2-4) in the case where the monovalent organic group has an acid group and a group that generates an acid group by heating include groups represented by the following formulae (r2-1) to formula (r2-4), respectively.

[0056] [Chemical Formula 8]

[0057]

[0058] (In the formulae (r2-1) to formula (r2-4), R 11 is a hydrogen atom or an alkyl group. PG is a monovalent thermally dissociable group. "*" represents a bond. )

[0059] The group represented by the formula (r2-2) and formula (r2-4) dissociates the group PG by heating, thereby generating an acid group. The group PG can include groups that bond to the oxygen atom in the formula (r2-2) or the nitrogen atom in the formula (r2-4) via a tertiary carbon atom, and the like. Specifically, for example, tert-butyl, 1-cyclopentylethyl, 1-cyclohexylethyl, 1-norbornylethyl, 1-phenylethyl, and the like can be mentioned.

[0060] • Crosslinkable group and group that generates crosslinkable group by heating

[0061] In the case where the monovalent organic group represented by the formula (r3-1) to formula (r3-9) has a crosslinkable group and a group that generates a crosslinkable group by heating, as the crosslinkable group, (meth)acryloyl group, alkenyl group, vinylphenyl group, β-hydroxyamide group, furanyl group, epoxy group, cyclic carbonate group, alcoholic hydroxyl group, phenolic hydroxyl group, isocyanate group, protected isocyanate group, trialkoxysilane group, maleimide group, and the like can be mentioned. As R 3 3 Specific examples of the monovalent organic group represented by the formula (r3-1) to formula (r3-9) in the case where the monovalent organic group has a crosslinkable group and a group that generates a crosslinkable group by heating include groups represented by the following formulae (r3-1) to formula (r3-9), respectively.

[0062] [Chemical Formula 9]

[0063]

[0064] (In the formulae (r3-1) to formula (r3-9), R 12 is a hydrogen atom or an alkyl group. R 13 is a hydrogen atom or a methyl group. "*" represents a bond. )

[0065] • Photo-orienting group

[0066] ​A photoreactive group is a functional group that imparts anisotropy to a film by a photoreaction such as photoisomerization, photodimerization, photo-Fries rearrangement, or photodecomposition caused by light irradiation.

[0067] As specific examples of the photoreactive group, for example, there can be mentioned an azobenzene-containing group including azobenzene or a derivative thereof as a basic skeleton, a cinnamic acid structure-containing group including cinnamic acid or a derivative thereof (cinnamic acid structure) as a basic skeleton, a chalcone-containing group including chalcone or a derivative thereof as a basic skeleton, a benzophenone-containing group including benzophenone or a derivative thereof as a basic skeleton, a coumarin-containing group including coumarin or a derivative thereof as a basic skeleton, a cyclobutane-containing structure including cyclobutane or a derivative thereof as a basic skeleton, a stilbene-containing group including stilbene or a derivative thereof as a basic skeleton, a phenyl benzoate-containing group including phenyl benzoate or a derivative thereof as a basic skeleton, and the like. Among them, the photoreactive group is preferably at least one selected from the group consisting of an azobenzene-containing group, a cinnamic acid structure-containing group, a chalcone-containing group, a stilbene-containing group, a cyclobutane-containing structure, and a phenyl benzoate-containing group, and particularly preferably a cinnamic acid structure-containing group or an azobenzene-containing group in terms of high sensitivity to light and easy introduction into a polymer.

[0068] As specific examples of the photoreactive group, for example, there can be mentioned groups represented by the following Formulas (r4-1) to (r4-4), and the like.

[0069] [Chemical Formula 10]

[0070]

[0071] (In Formulas (r4-1) to (r4-4), R is a hydrogen atom or a monovalent organic group. X 3 is -O- or -NH-. "*" represents a bond. )

[0072] • Vertical alignment group

[0073] A vertical alignment group is a group that exhibits a property of vertically aligning liquid crystal molecules irrespective of light irradiation, and is a group that imparts a pretilt angle to liquid crystals. As specific examples of the vertical alignment group, for example, there can be mentioned an alkyl group having a carbon number of 3 to 30, a fluorine-containing alkyl group having a carbon number of 3 to 30, an alkoxy group having a carbon number of 3 to 30, a group represented by the following Formula (9), and a group having a steroid skeleton having a carbon number of 17 to 51, and the like.

[0074] [Chemical Formula 11]

[0075]

[0076] (In Formula (9), A1 ~A 3 are each independently phenylene or cyclohexylene, and can have a substituent in the ring portion. 21 is a hydrogen atom, an alkyl group having a carbon number of 1 to 20, an alkoxy group having a carbon number of 1 to 20, an alkyl group having a carbon number of 1 to 20 in which at least one hydrogen atom is substituted with a fluorine atom, an alkoxy group having a carbon number of 1 to 20 in which at least one hydrogen atom is substituted with a fluorine atom, or a fluorine atom, R 22 and R 23 are each independently a single bond, -O-, -COO-, -OCO-, or an alkandiyl group having a carbon number of 1 to 3. k, m, and n are integers of 0 or more satisfying 1≦k+m+n≦4. In R 21 is a hydrogen atom, an alkyl group having a carbon number of 1 to 3, or a fluorine atom, k+m+n satisfies k+m+n≧2.

[0077] "*" indicates a bond.

[0078] As specific examples of the group represented by the formula (9), for example, the groups represented by the following formulae (r5-1) to (r5-7), and the like can be given, but are not limited thereto. As A 1 ~A 3 The substituent which can be present in the ring portion, for example, a fluorine atom, an alkyl group having a carbon number of 1 to 3, an alkoxy group having a carbon number of 1 to 3, and the like can be given.

[0079] [Chemical Formula 12]

[0080]

[0081] (In the formulae (r5-1) to (r5-7), R is a hydrogen atom, a fluorine atom, an alkyl group having a carbon number of 1 to 20, an alkoxy group having a carbon number of 1 to 20, or a fluoroalkyl group having a carbon number of 1 to 20. "*" indicates a bond.)

[0082] • Photoinitiator Group

[0083] The photoinitiator group is a site which generates a polymerization initiation ability by light or a site which has a photosensitizing action, and is a group having a structure of a compound (photoinitiator) which is capable of initiating polymerization of a polymerizable component by irradiation of a radiation such as visible light, ultraviolet light, far ultraviolet light, an electron beam, X-rays, and the like. The photoinitiator group is preferably a group having a structure of a radical polymerization initiator which is capable of generating a radical by light irradiation. Specifically, for example, a group having a structure of a compound containing a radical generation site such as a benzalkyl ketone-based compound, a benzoin-based compound, a ketal-based compound, an acetophenone-based compound, a benzophenone-based compound, a thioxanthone-based compound, and an anthraquinone-based compound can be given.

[0084] As specific examples of the photoinitiator group, for example, the groups represented by the following formulae (r6-1) to (r6-11), and the like can be given.

[0085] [Chemical Formula 13]

[0086]

[0087] (In formulae (r6-1) to (r6-11), R is a hydrogen atom or an alkyl group. "*" indicates a bond.)

[0088] • Electron-transporting group and hole-transporting group

[0089] As the electron-transporting group, for example, a group having a ring structure of an imidazole ring, a pyridine ring, a pyrazine ring, an oxadiazole ring, a triazine ring, a triazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, a thiadiazole ring, a quinoxaline ring, a quinoline ring, an isoquinoline ring, or the like can be exemplified.

[0090] As the hole-transporting group, for example, a group having an aromatic amine structure (triphenylamine structure, diphenylamine structure, or the like), a carbazole ring, a thiophene ring, or the like can be exemplified.

[0091] X 1 and the other of X 2 is -OR 4 . R 4 is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. In terms of stability of liquid crystal alignment even in the case where the liquid crystal alignment film becomes a thin film due to coating failure or the like and sufficient reduction in generation of AC image sticking, R 4 is preferably a monovalent organic group having 1 or more carbon atoms. As the monovalent organic group, the same groups as exemplified as the monovalent organic group represented by R 3 are exemplified. If R 4 is a monovalent organic group having 1 or more carbon atoms, the detachment of the formula (6) due to reverse reaction at the time of post-baking can be suppressed, and in the case where the liquid crystal alignment film becomes a thin film, generation of AC image sticking can also be suppressed, which is preferable in terms of this aspect. In addition, in the case where the polymeric (P) and other polymers are contained together in the liquid crystal alignment agent, phase separation can be ensured, which is preferable in terms of this aspect. Among them, in terms of stability of the structure of the side chain, R 4 is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms.

[0092] Further, in the formula (1) among the formulae (1) to (5), the two groups "-CO-X 1 " and the group "-CO-X 2 " take a specific isomer structure, and the two groups exist on the same side. In contrast to this, the formulae (2) to (5) do not particularly specify the isomer structure of the two groups "-CO-X 1 " and the group "-CO-X 2 ".

[0093] From the viewpoint of heat resistance and the viewpoint of easy introduction of the group represented by the formula (6) to the side chain, the polymer (P) is preferably a polymer having a structural unit derived from a monomer containing a polymerizable carbon-carbon unsaturated bond. The kind of the monomer containing a polymerizable carbon-carbon unsaturated bond constituting the polymer (P) is not particularly limited, and for example, maleic anhydride compounds, (meth)acrylic compounds, aromatic vinyl compounds, maleimide compounds, olefinic hydrocarbons, cyclic olefinic hydrocarbons, and the like can be exemplified. The " *1" in the formulae (1) to (5) is preferably a bonding bond to a carbon atom constituting the main chain of the polymer.

[0094] The content of the structural unit U1 in the polymer (P) is preferably 5 mol% or more, more preferably 10 mol% or more, relative to all the structural units constituting the polymer (P). In addition, the content of the structural unit U1 in the polymer (P) is preferably 90 mol% or less, more preferably 80 mol% or less, relative to all the structural units constituting the polymer (P). If the content of the structural unit U1 is in the range, the voltage retention rate can be kept high even in the case of heating during film formation for a long time, and even in the case where the film thickness of the liquid crystal alignment film is thinned due to coating failure or the like, residual images are less likely to occur, and the improvement effect of long-term heat resistance can be sufficiently obtained, which is preferable from the above-mentioned aspect.

[0095] (Other structural units)

[0096] The polymer (P) can be a polymer containing only the structural unit U1, but can also have the structural unit U1 and other structural units different from the structural unit U1. As the other structural units, a structural unit not having the structural unit represented by the formula (6) can be used. Specifically, the structural unit U2 having a cyclic carbonate structure; the structural unit U3 having a -COOR 5 (wherein, R 5 is a monovalent thermally dissociable group); the structural unit U4 derived from a monomer selected from the group consisting of a compound represented by the following formula (8-1), a compound represented by the following formula (8-2), an N-substituted aromatic maleimide compound, an olefinic hydrocarbon, and a compound generating an isocyanate group by heating; and the like can be exemplified.

[0097] • Structural unit U2

[0098] In the case where the polymer (P) has the structural unit U2, an epoxy group can be generated by heating (preferably in the process of applying the liquid crystal alignment agent to a substrate and heating to form a liquid crystal alignment film). The generated epoxy group functions as a crosslinkable group, whereby the improvement effect of long-term heat resistance can be further improved for the obtained liquid crystal element, which is preferable from this aspect.

[0099] The structural unit U2 is preferably a structural unit derived from a monomer containing a polymerizable carbon-carbon unsaturated bond and a cyclic carbonate group. Specifically, the following structural units represented by Formulas (10-1) to (10-3) can be exemplified.

[0100] [Chem. 14]

[0101]

[0102] (In Formulas (10-1) to (10-3), R 21 , R 22 , and R 23 are each independently a hydrogen atom or a monovalent organic group. R 24 is a hydrogen atom or a methyl group. Z 1 is an oxygen atom or -NH-. X 1 is a single bond or a divalent linking group. n1 is 0 or 1. n2 is an integer of 0 to 2.)

[0103] The content of the structural unit U2 in the polymer (P) is preferably 2 mol% or more, more preferably 5 mol% or more, and further preferably 10 mol% or more, relative to all the structural units constituting the polymer (P). In addition, the content of the structural unit U2 in the polymer (P) is preferably 60 mol% or less, and more preferably 55 mol% or less, relative to all the structural units constituting the polymer (P). If the content of the structural unit U2 is in the above range, thermal decomposition of the polymer can be sufficiently suppressed at the time of heat treatment at the time of film formation, and even in the case where the film thickness of the liquid crystal alignment film is thinned due to coating failure or the like, residual images are less likely to occur, and the improvement effect of long-term heat resistance can be sufficiently obtained, which is preferable in terms of the above aspects. The polymer (P) can have only one kind of structural unit U2, or two or more kinds of structural units U2.

[0104] • Structural Unit U3

[0105] In the case where the polymer (P) has the structural unit U3, a carboxyl group can be generated by heating (preferably, in the process of coating the liquid crystal alignment agent on a substrate and performing heating to form a liquid crystal alignment film). The generated carboxyl group functions as a crosslinkable group, and thus, for the obtained liquid crystal element, the improvement effect of long-term heat resistance can be further improved, which is preferable in terms of the above aspects.

[0106] As a specific example of the group "-COOR 5 ", the following structure represented by Formula (X-1), an acetal ester structure of a carboxylic acid, a ketal ester structure of a carboxylic acid, and the like can be exemplified.

[0107] [Chem. 15]

[0108]

[0109] (in the formula (X-1), R 31 , R 32 , and R 33 are (i) or (ii) below. (i) R 31 , R 32 , and R 33 are each independently an alkyl group having 1 to 10 carbons or a monovalent alicyclic hydrocarbon group having 3 to 20 carbons. (ii) R 31 and R 32 indicate an alicyclic hydrocarbon structure or a cyclic ether structure having 4 to 20 carbons which are formed by combining with each other and with the carbon atoms to which R 31 and R 32 are bonded. R 33 is an alkyl group having 1 to 10 carbons, an alkenyl group having 2 to 10 carbons, or an aryl group having 6 to 20 carbons. "*" indicates a bonding bond.)

[0110] As specific examples of the structure represented by the formula (X-1), there can be mentioned t-butoxycarbonyl, 1-cyclopentylethoxycarbonyl, 1-cyclohexylethoxycarbonyl, 1-norbornylethoxycarbonyl, 1-phenylethoxycarbonyl, 1-(1-naphthyl)ethoxycarbonyl, 1-benzyloxycarbonyl, 1-phenethyl ethoxycarbonyl, and the like.

[0111] As specific examples of the acetal ester structure of the carboxylic acid, there can be mentioned, for example, 1-methoxyethoxycarbonyl, 1-ethoxyethoxycarbonyl, 1-propoxyethoxycarbonyl, 1-butoxyethoxycarbonyl, 1-cyclohexyloxyethoxycarbonyl, 1-phenoxyethoxycarbonyl, 2-tetrahydrofuryloxy carbonyl, 2-tetrahydropyranyloxy carbonyl, and the like.

[0112] As specific examples of the ketal ester structure of the carboxylic acid, there can be mentioned 1-methyl-1-methoxyethoxycarbonyl, 1-methyl-1-ethoxyethoxycarbonyl, 1-methyl-1-propoxyethoxycarbonyl, 1-methyl-1-butoxyethoxycarbonyl, 1-methyl-1-cyclohexyloxyethoxycarbonyl, 2-(2-methyltetrahydrofuryl)oxy carbonyl, 2-(2-methyltetrahydropyranyl)oxy carbonyl, 1-methoxycyclopentyloxy carbonyl, 1-methoxycyclohexyloxy carbonyl, and the like.

[0113] The structural unit U3 is preferably a structural unit derived from a monomer containing a polymerizable carbon-carbon unsaturated bond and a group "-COOR 5 ". Specifically, there can be mentioned the structural units represented by the following formulas (7-1) to (7-3), respectively.

[0114] [Chem. 16]

[0115]

[0116] (in the formulas (7-1) to (7-3), R41 , R 42 , and R 43 are each independently a hydrogen atom or a monovalent organic group. R 44 is a hydrogen atom or a methyl group. Z 2 is an oxygen atom or -NH-. X 2 is a single bond or a divalent linking group. R 5 is a monovalent thermally dissociable group. m1 is 0 or 1.

[0117] The content of the structural unit U3 in the polymer (P) is preferably 2 mol% or more, more preferably 5 mol% or more, and further preferably 10 mol% or more, relative to all the structural units constituting the polymer (P). In addition, the content of the structural unit U3 in the polymer (P) is preferably 65 mol% or less, and more preferably 60 mol% or less, relative to all the structural units constituting the polymer (P). If the content of the structural unit U3 is in the above range, thermal decomposition of the polymer can be sufficiently suppressed at the time of heating at the time of film formation, and even in the case where the film thickness of the liquid crystal alignment film is thinned due to coating failure or the like, residual images are less likely to occur, and the improvement effect of long-term heat resistance can be sufficiently obtained, which is preferable in terms of the above aspects. The polymer (P) can have only one kind of the structural unit U3, or two or more kinds thereof.

[0118] • Structural unit U4

[0119] The polymer (P) can also include a structural unit U4 (other than the structural unit U1, the structural unit U2, and the structural unit U3) derived from a monomer selected from the group consisting of a compound represented by the following formula (8-1), a compound represented by the following formula (8-2), an N-substituted aromatic maleimide compound, an olefinic hydrocarbon, and a (meth)acrylic compound that generates an isocyanate group by heating. By including the structural unit U4 in the polymer (P), the thermal stability of the side chain can be further ensured, and the improvement effect of long-term heat resistance of the obtained liquid crystal element can be further improved, which is preferable in terms of the above aspects.

[0120] [Chemical Formula 17]

[0121]

[0122] (In formula (8-1), R 18 is a hydrogen atom or a monovalent hydrocarbon group having a carbon number of 1 to 10. Ar 1 is a divalent aromatic ring group. 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 of 0 to 3. r is 0 or 1.

[0123] With respect to the compound represented by the formula (8-1), Ar 1The aromatic ring group represented is a group in which two hydrogen atoms are removed from a substituted or unsubstituted aromatic ring. As the aromatic ring, aromatic hydrocarbon rings, aromatic nitrogen-containing heterocyclic rings can be exemplified. As the aromatic hydrocarbon ring, benzene rings, naphthalene rings, anthracene rings, and the like can be exemplified. As the aromatic nitrogen-containing heterocyclic ring, for example, pyridine rings, piperazine rings, and the like can be exemplified.

[0124] R 19 The monovalent organic group represented is, for example, a monovalent hydrocarbon group having a carbon number of 1 to 20, a monovalent organic group having a liquid crystal origin structure having a carbon number of 6 to 30, and the like.

[0125] R 18 It is preferably a hydrogen atom, a monovalent hydrocarbon group having a carbon number of 1 to 5, or a phenyl group.

[0126] As a specific example of the compound represented by the formula (8-1), for example, styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 5-tert-butyl-2-methylstyrene, divinylbenzene, trivinylbenzene, t-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, diphenyl ethylene, vinyl naphthalene, 4-vinylpyridine, compounds represented by the following formulae (8-1-1) and (8-1-2), and the like can be exemplified.

[0127] [Chemical Formula 18]

[0128]

[0129] (In the formulae (8-1-1) and (8-1-2), R 20 is a hydrogen atom, an alkyl group having a carbon number of 1 to 20, or an alkoxy group having a carbon number of 1 to 20.)

[0130] As the olefinic hydrocarbon, for example, ethylene, propylene, butylene, pentene, and the like can be exemplified. As the compound represented by the formula (8-2), norbornene, methyl norbornene, and the like can be exemplified.

[0131] The N-substituted aromatic maleimide compound is a compound in which the hydrogen atom bonded to the nitrogen atom in the maleimide is substituted with a monovalent organic group having an aromatic ring. As the aromatic ring, benzene rings, naphthalene rings can be exemplified, and these rings can have a substituent. As the substituent, for example, an alkyl group having a carbon number of 1 to 10, an alkoxy group having a carbon number of 1 to 10, a halogen atom, a carboxyl group, and the like can be exemplified.

[0132] As specific examples of the N-substituted aromatic maleimide compound, there can be mentioned N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(4-ethylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-benzylmaleimide, N-naphthylmaleimide, N-(4-carboxyphenyl)maleimide, and the like.

[0133] As the (meth)acrylic compound which generates an isocyanate group by heating, there can be mentioned a reaction product of (meth)acryloyloxyethyl isocyanate with diethyl malonate, a reaction product of (meth)acryloyloxyethyl isocyanate with 3,5-dimethylpyrazole, a reaction product of (meth)acryloyloxyethyl isocyanate with methyl ethyl ketone oxime, and the like.

[0134] The content of the structural unit U4 in the polymer (P) is preferably 1 mol% or more, more preferably 2 mol% or more, and further preferably 5 mol% or more, relative to all the structural units constituting the polymer (P). In addition, the content of the structural unit U4 in the polymer (P) is preferably 50 mol% or less, and more preferably 40 mol% or less, relative to all the structural units constituting the polymer (P). If the content of the structural unit U4 is in the above range, the long-term heat resistance can be more excellent while maintaining the electric properties and the like in a good state, which is preferable in this respect. The polymer (P) can have only one kind of the structural unit U4, or can have two or more kinds thereof.

[0135] In addition to the above, the polymer (P) can further include a structural unit different from the structural unit U2 to the structural unit U4 as another structural unit. As the other structural unit, there can be mentioned, for example, an alkyl (meth)acrylate, a (meth)acrylate having an alicyclic structure, a (meth)acrylate having an aromatic ring structure, a conjugated diene compound, and the like. The content ratio of these structural units is preferably 30 mol% or less, and more preferably 25 mol% or less, relative to all the structural units constituting the polymer (P).

[0136] (Synthesis of the polymer (P))

[0137] The polymer (P) can be obtained by reacting a polymer including a structural unit having a maleic anhydride structure, with a primary or secondary amine having a partial structure represented by the formula (5) as a reactive compound. More specifically, it can be manufactured by a method including the following Process A.

[0138] Process A: a process of reacting a polymer (x) having a structural unit U5 derived from at least one compound (hereinafter, also referred to as "anhydride group-containing compound") selected from the group consisting of a compound represented by the following formula (11), a compound represented by the following formula (12), a compound represented by the following formula (13), and a compound represented by the following formula (14), with a compound (y) represented by the following formula (5)

[0139] [Chemical Formula 19]

[0140]

[0141] (In formula (11), n is 0 or 1. In formula (13) and formula (14), A 1 is a methylene group, an ethylene group, a sulfur atom, or an oxygen atom. m is 1 or 2.)

[0142] [Chemical Formula 20]

[0143]

[0144] (In formula (15), R 1 is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. R 2 is an alkanediyl group. R 3 is a monovalent organic group having 1 or more carbon atoms.)

[0145] • Anhydride group-containing compound

[0146] In the synthesis of the polymer (x), a polymer having a maleic anhydride structure can be obtained by polymerizing a monomer containing an anhydride group-containing compound. As a preferable specific example of the anhydride group-containing compound, a compound represented by the following formula (16-1) to formula (16-9), and the like can be given.

[0147] [Chemical Formula 21]

[0148]

[0149] Among them, in terms of the stereoscopic structure being specified, an imide ring being easily formed by post-baking, and thus a polymer (P) having more excellent long-term heat resistance and structural stability of a side chain being obtained, the anhydride group-containing compound used in the synthesis of the polymer (x) is particularly preferably a compound represented by the above formula (16-1), formula (16-3) to formula (16-8), respectively. Further, in the synthesis of the polymer (x), one kind of anhydride group-containing compound can be used alone, or two or more kinds thereof can be used in combination.

[0150] • Compound (y)

[0151] The compound (y) is preferably a primary amine or a secondary amine having the functional group. As specific examples of the compound (y), for example, compounds represented by the following Formulas (17-1) to (17-28), and the like can be given. Further, one kind of the compound (y) can be used alone or two or more kinds of the compound (y) can be used in combination at the time of production of the polymer (P).

[0152] [Chemical Formula 22]

[0153]

[0154] [Chemical Formula 23]

[0155]

[0156] [Chemical Formula 24]

[0157]

[0158] [Chemical Formula 25]

[0159]

[0160] The method for synthesizing the polymer (x) is not particularly limited, and can be performed according to the conventional method of organic chemistry. In the case where the polymer (x) is produced by a radical polymerization method, the polymerization reaction is preferably performed in the presence of a polymerization initiator in an organic solvent. As the polymerization initiator used, for example, an azo compound such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), or the like is preferred. The use ratio of the polymerization initiator is preferably set to 0.01 to 30 parts by mass with respect to 100 parts by mass of all the monomers used in the reaction. As the organic solvent used, for example, an alcohol, an ether, a ketone, an amide, an ester, a hydrocarbon compound, or the like can be given.

[0161] In the polymerization reaction, the reaction temperature is preferably set to 30 to 120°C, and the reaction time is preferably set to 1 to 36 hours. The amount (a) of the organic solvent used is preferably set to an amount of 0.1 to 60% by mass with respect to the total amount (a+b) of the reaction solution with respect to the total amount (b) of the monomers used in the reaction. The reaction solution in which the polymer is dissolved can be separated, for example, by a conventional separation method such as a method in which the reaction solution is injected into a large amount of a poor solvent, and the precipitate thus obtained is dried under reduced pressure, or a method in which the reaction solution is removed by distillation under reduced pressure using an evaporator.

[0162] Further, the polymer (x) can be produced by, in addition to the radical polymerization, a conventional polymerization method such as ring-opening metathesis polymerization (ROMP), polymerization using a metallocene catalyst, or the like depending on the kind of monomer used.

[0163] The reaction of the polymer (x) with the compound (y) is preferably performed in an organic solvent, if necessary in the presence of a catalyst. As the catalyst, a pyridine derivative such as N,N-dimethylaminopyridine; a tertiary amine such as triethylamine can be exemplified, but is not limited thereto. In the case where a catalyst is used, the proportion of the catalyst used is preferably set to 0.01 to 0.5 molar equivalent relative to the total amount of the structural unit U5 possessed by the polymer (x).

[0164] The proportion of the compound (y) used is preferably set to 10 mol or more, more preferably 30 mol or more, and further preferably 50 mol or more, relative to 100 mol of the total amount of the structural unit U5 possessed by the polymer (x). In addition, the proportion of the compound (y) used is preferably set to 200 mol or less, and more preferably 150 mol or less, relative to 100 mol of the total amount of the structural unit U5 possessed by the polymer (x). Further, as the compound (y), one kind alone can be used, or two or more kinds in combination can be used.

[0165] As the organic solvent used at the time of the reaction, for example, an alcohol, an ether, a ketone, an amide, an ester, a hydrocarbon compound, or the like can be exemplified. The reaction temperature of the reaction is preferably set to 30 to 120°C, and the reaction time is preferably set to 1 to 24 hours. Thus, a solution in which the polymer (P) is dissolved can be obtained. As to this reaction solution, the polymer (P) contained in the reaction solution can be separated using a conventional separation method, and then used for the production of a liquid crystal aligning agent.

[0166] • Step B

[0167] The polymer (P) can be the polymer produced by Step A, or can be the polymer produced by a method including the following Step B on the basis of Step A. By containing the polymer produced by the method including Step B in the liquid crystal aligning agent, the structural stability of the side chain can be further improved, and a liquid crystal element having more excellent long-term heat resistance can be obtained, which is preferred in view of the above.

[0168] Step B: a step of reacting a reaction product of the polymer (x) and the compound (y) with an esterification agent

[0169] The esterifying agent is not particularly limited as long as it is a compound capable of esterifying the carboxyl group generated in the side chain by the reaction of the polymer (x) with the compound (y). Among them, the esterifying agent can be preferably used from the viewpoint of efficiently performing esterification. Examples of the esterifying agent include diazomethane, trimethylsilyldiazomethane, a mixture of boron trifluoride and an alcohol, a compound represented by the following formula (16), a compound represented by the following formula (17), or a compound represented by the following formula (18).

[0170] [Chemical Formula 26]

[0171]

[0172] (In formula (16), R 7 is a hydrogen atom or a methyl group. R 8 and R 9 are each independently a monovalent organic group. In formula (17), R 10 to R 12 are each independently a monovalent organic group. R 13 is a hydrogen atom or a monovalent organic group. In formula (18), R 14 , R 15 , and R 16 are each independently a monovalent organic group. R 17 is a hydrogen atom or a monovalent organic group.)

[0173] Examples of the monovalent organic group represented by R 8 and R 9 in formula (16), R 10 to R 12 in formula (17), and R 13 to R 16 in formula (18) include a monovalent chain hydrocarbon group, a monovalent alicyclic hydrocarbon group, a group in which any hydrogen atom of a monovalent chain hydrocarbon group or alicyclic hydrocarbon group is substituted with a hydroxyl group or a carboxyl group, a group in which any methylene group of a monovalent chain hydrocarbon group or alicyclic hydrocarbon group is substituted with a carbonyl group, an amido group, a urea bond, or a carbamic acid ester bond, and the like.

[0174] Examples of the compound represented by formula (16) to formula (18) include a compound represented by the following formula (20-1) to formula (20-5), and the like.

[0175] [Chemical Formula 27]

[0176]

[0177] The reaction of the reaction product of the polymer (x) and the compound (y) with the esterification agent is preferably performed in an organic solvent. As the organic solvent, a solvent capable of dissolving or dispersing the reaction product and the esterification agent is preferred. The reaction temperature at this time is preferably from 0°C to 80°C, more preferably from 10°C to 60°C. The reaction time is, for example, from 30 minutes to 12 hours.

[0178] The weight average molecular weight (Mw) of the polymer (P) in terms of polystyrene as measured by gel permeation chromatography (GPC) is preferably from 1,000 to 300,000, more preferably from 2,000 to 100,000. The molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) as measured by GPC is preferably 8 or less, more preferably 6 or less. Furthermore, the polymer (P) used in the production of the liquid crystal alignment agent can be only one or two or more in combination.

[0179] The content ratio of the polymer (P) in the liquid crystal alignment agent with respect to the total amount of the polymer component contained in the liquid crystal alignment agent is preferably 1% by mass or more, more preferably 2% by mass or more, and further preferably 5% by mass or more. In addition, the content ratio of the polymer (P) with respect to the total amount of the polymer component contained in the liquid crystal alignment agent is preferably 40% by mass or less, more preferably 30% by mass or less, and further preferably 25% by mass or less. As the polymer (P), one kind alone or two or more in combination can be used.

[0180] <Other Components>

[0181] The liquid crystal alignment agent of the present disclosure contains the polymer (P) as described above, but can also contain other components other than the polymer (P) as necessary.

[0182] (Polymer (Q))

[0183] From the viewpoint of further improving the electrical properties or reliability, the liquid crystal alignment agent of the present disclosure preferably further contains a polymer (Q) different from the polymer (P).

[0184] As the polymer (Q), for example, a polyamide acid, a polyimide, a polyamide acid ester, a polyamide, a polyorganosiloxane, a polymer of a monomer having an unsaturated bond, or the like can be exemplified. Among them, from the viewpoints of improvement of the electrical properties, affinity with the liquid crystal, mechanical strength, and affinity with the polymer (P), the polymer (Q) is particularly preferably at least one selected from the group consisting of a polyamide acid, a polyamide acid ester, and a polyimide.

[0185] The amount of the polymer (Q) contained in the liquid crystal alignment agent is preferably such that the polymer (P) is present in an amount of 100 parts by mass or more, more preferably 100 parts by mass to 2000 parts by mass, and even more preferably 200 parts by mass to 1500 parts by mass, with respect to 100 parts by mass of the polymer (Q) used in the production of the liquid crystal alignment agent, from the viewpoint of balancing the effects brought about by the adjustment of the polymer (Q) and the effects brought about by the adjustment of the polymer (P).

[0186] • Polyamic acid, polyamic acid ester, and polyimide

[0187] The polyamic acid, polyamic acid ester, and polyimide contained in the liquid crystal alignment agent can be synthesized according to conventional methods. For example, the polyamic acid can be obtained by reacting a tetracarboxylic dianhydride with a diamine. The polyamic acid ester can be obtained, for example, by a method such as reacting the polyamic acid obtained in the above with an esterifying agent (e.g., methanol or ethanol, N,N-dimethylformamide diethyl acetal, or the like). The polyimide can be obtained, for example, by dehydration ring closure and imidization of the polyamic acid obtained in the above. The polyimide preferably has an imidization rate of 20% to 95%, and more preferably 30% to 90%. The imidization rate is a proportion of the number of imide ring structures with respect to the total number of the number of amic acid structures and the number of imide ring structures, expressed in percentage.

[0188] The tetracarboxylic dianhydride used in the polymerization is not particularly limited, and various tetracarboxylic dianhydrides can be used. As specific examples thereof, aliphatic tetracarboxylic dianhydrides such as butane tetracarboxylic dianhydride, ethylenediaminetetraacetic dianhydride; alicyclic tetracarboxylic dianhydrides such as 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 2,3,5-tricarboxy cyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentane tetracarboxylic dianhydride, cyclohexane tetracarboxylic dianhydride; aromatic tetracarboxylic dianhydrides such as pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, p-phenylene bis(trimellitic acid monoester anhydride), ethylene glycol bis(trimellitic anhydride), 1,3-propanediol bis(trimellitic anhydride), and the like, and in addition to these, the tetracarboxylic dianhydride described in Japanese Patent Application Publication No. 2010-97188 can be used. Furthermore, the tetracarboxylic dianhydride can be used alone or in combination with two or more kinds.

[0189] As the diamine used in the polymerization, for example, aliphatic diamines such as ethylenediamine, tetramethylenediamine, and the like; alicyclic diamines such as p-cyclohexanediamine, 4,4'-methylenebis(cyclohexylamine), and the like; side chain type aromatic diamines such as hexadecyloxydiaminobenzene, cholexyloxydiaminobenzene, cholestanoyloxydiaminobenzoic acid, cholestanoyloxydiaminobenzoic acid, cholestanoyloxydiaminobenzoic acid, 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, compounds represented by the following formulae (2-1) to (2-4), respectively, and the like; and non-side chain type aromatic diamines such as p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylamine, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,2-bis(4-aminophenoxy)ethane, 1,5-bis(4-aminophenoxy)pentane, bis[2-(4-aminophenyl)ethyl]hexanedioic 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, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-(phenylenediisopropylidene)dianiline, 1,4-bis(4-aminophenoxy)benzene, 4-(4-aminophenoxy carbonyl)-1-(4-aminophenyl)piperidine, 4,4'-[4,4'-propane-1,3-diylbis(piperidin-1,4-diyl)]dianiline, and the like; and diaminoorganosiloxanes such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and the like, in addition to the above, can be used. Furthermore, the diamine can be used singly or in combination of two or more.

[0190] [Chem. 28]

[0191]

[0192] p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylamine, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,2-bis(4-aminophenoxy)ethane, 1,5-bis(4-aminophenoxy)pentane, bis[2-(4-aminophenyl)ethyl]hexanedioic 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, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-(phenylenediisopropylidene)dianiline, 1,4-bis(4-aminophenoxy)benzene, 4-(4-aminophenoxy carbonyl)-1-(4-aminophenyl)piperidine, 4,4'-[4,4'-propane-1,3-diylbis(piperidin-1,4-diyl)]dianiline, and the like; and diaminoorganosiloxanes such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and the like, in addition to the above, can be used. Furthermore, the diamine can be used singly or in combination of two or more.

[0193] As the diamine used in the polymerization, in addition to the above, for example, a diamine containing a photoalignment group or a diamine containing an initiator group, nitrogen-containing diamines represented by the following formulae (19-1) to (19-10), respectively, and the like can be used.

[0194] [Chem. 29]

[0195]

[0196] The weight average molecular weight (Mw) of the polyamic acid, polyamic acid ester, and polyimide contained in the liquid crystal alignment agent, as measured by GPC, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000, in terms of polystyrene. The molecular weight distribution (Mw / Mn) is preferably 7 or less, more preferably 5 or less. Furthermore, the polyamic acid, polyamic acid ester, and polyimide contained in the liquid crystal alignment agent can be only one, or two or more can be combined.

[0197] (Cross-linking agent)

[0198] The liquid crystal alignment agent of the present disclosure can further contain a cross-linking agent. As the cross-linking agent, a compound having a functional group capable of reacting with a functional group possessed by the polymer (P) or other polymers (e.g., an amino group, a carboxyl group, an epoxy group, a polymer unsaturated bond group, etc.) can be exemplified. As the functional group possessed by the cross-linking group, specifically, a cyclic ether group, a carboxyl group, a cyclic carbonate group, an alcoholic hydroxyl group, a β-hydroxy amide group, an amino group, a protected amino group, a protected isocyanate group, a trialkoxysilane group, a polymerizable unsaturated bond group, a maleimide group, etc. can be exemplified. The number of cross-linking groups possessed by the cross-linking agent is preferably two or more, more preferably three or more, and further preferably 3 to 6.

[0199] In the case of formulating a cross-linking agent, the content ratio of the cross-linking agent in the liquid crystal alignment agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of the total amount of the polymer component in the liquid crystal alignment agent. In addition, from the viewpoint of suppressing a decrease in performance due to the addition of an excess amount, the content ratio of the cross-linking agent is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, relative to 100 parts by mass of the total amount of the polymer component in the liquid crystal alignment agent. Furthermore, as the cross-linking agent, one kind alone or two or more in combination can be used.

[0200] (Solvent)

[0201] The liquid crystal alignment agent is usually prepared in the form of a liquid composition in which the polymer (P) and other components, if necessary, are dispersed or dissolved in a suitable solvent.

[0202] As the organic solvent used, for example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate, and the like can be exemplified. They can be used alone or in a mixture of two or more kinds.

[0203] As the other component, in addition to the above, for example, a low molecular compound having at least one epoxy group in the molecule (for example, ethylene glycol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylylenediamine, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, and the like) having a molecular weight of 1000 or less, a functional silane compound, a polyfunctional (meth)acrylate, an antioxidant, a metal chelate compound, a hardening accelerator, a surfactant, a filler, a dispersant, a photo sensitizer, and the like can be exemplified. The blending ratio of the other component can be appropriately selected depending on the compound, within a range not impairing the effects of the present disclosure.

[0204] The solid component concentration in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent of the liquid crystal alignment agent in the total mass of the liquid crystal alignment agent) can be appropriately selected in consideration of viscosity, volatility, and the like, and is preferably in the range of 1 to 10 mass%. That is, the liquid crystal alignment agent is coated on the surface of a substrate as described later, preferably with heating, thereby forming a coating film that is a liquid crystal alignment film or becomes a liquid crystal alignment film. At this time, if the solid component concentration is 1 mass% or more, the film thickness of the coating film can be sufficiently ensured, and a good liquid crystal alignment film can be easily obtained, which is preferable from this viewpoint. In addition, if the solid component concentration is 10 mass% or less, the film thickness of the coating film does not become excessively large, a good liquid crystal alignment film can be obtained, and the viscosity of the liquid crystal alignment agent can be moderately ensured, and the coatability can be made good.

[0205] <<Liquid crystal alignment film and liquid crystal element>>

[0206] The liquid crystal alignment film of the present disclosure can be formed from the liquid crystal alignment agent prepared as described. In addition, the liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described. The mode of operation of the liquid crystal in the liquid crystal element is not particularly limited, and can be applied, for example, to various modes such as a Twisted Nematic (TN) mode, a Super Twisted Nematic (STN) mode, a Vertical Alignment (VA) mode (including a Vertical Alignment-Multi-domain Vertical Alignment (VA-MVA) mode, a Vertical Alignment-Patterned Vertical Alignment (VA-PVA) mode, and the like), an In-Plane Switching (IPS) mode, a Fringe Field Switching (FFS) mode, an Optically Compensated Bend (OCB) mode, and the like. The liquid crystal element can be manufactured, for example, by a method including Process 1 to Process 3 below. In Process 1, the substrate differs depending on the desired mode of operation. Processes 2 and 3 are common to each mode of operation.

[0207] (Process 1: Formation of a coating film)

[0208] First, the liquid crystal alignment agent is applied to a substrate, and preferably the application surface is heated, thereby forming a coating film on the substrate. As the substrate, for example, a float glass, a soda glass, or the like can be used; a transparent substrate including a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly(alicyclic olefin), or the like. As a transparent conductive film provided on one surface of the substrate, a NESA (NESA is a registered trademark of PPG Industries, Inc.) film including tin oxide (Sn02), an Indium Tin Oxide (ITO) film including indium oxide-tin oxide (In203-Sn02), or the like can be used. In the case of manufacturing a liquid crystal element of a TN mode, an STN mode, or a VA mode, two pieces of substrates provided with a patterned transparent conductive film are used. On the other hand, in the case of manufacturing a liquid crystal element of an IPS mode or an FFS mode, a substrate provided with an electrode including a transparent conductive film or a metal film patterned in a comb shape, and an opposing substrate not provided with an electrode are used. As the metal film, for example, a film including a metal such as chromium can be used. The application of the liquid crystal alignment agent to the substrate is preferably performed on the electrode formation surface using a flexographic printing method, a spin coating method, a roll coater method, or an inkjet printing method.

[0209] After the liquid crystal alignment agent is applied, preheating (pre-baking) is preferably performed for the purpose of preventing sagging of the applied liquid crystal alignment agent, or the like. The pre-baking temperature is preferably from 30°C to 150°C, more preferably from 40°C to 120°C. The pre-baking time is preferably from 0.25 minutes to 10 minutes.

[0210] Thereafter, a calcination (post-baking) process is performed for the purpose of further removing the solvent and, as necessary, thermally imidizing the amide acid structure present in the polymer. From the viewpoint of suppressing deterioration such as discoloration caused by high temperatures when forming the liquid crystal alignment film on the color filter, and the viewpoint of reducing environmental load, the calcination temperature (post-baking temperature) at this time is preferably 250°C or lower, more preferably 230°C or lower, and further preferably 180°C or lower. In addition, from the viewpoint of suppressing a decrease in liquid crystal alignment properties or reliability due to the influence of the solvent component remaining in the film, the post-baking temperature is preferably 80°C or higher, and more preferably 120°C or higher. The post-baking time is preferably from 5 minutes to 150 minutes. The film thickness of the film thus formed is preferably from 0.001 μm to 1 μm. After the liquid crystal alignment agent is applied to the substrate, the organic solvent is removed, thereby forming a liquid crystal alignment film, or a coating film that becomes a liquid crystal alignment film.

[0211] (Step 2: alignment treatment)

[0212] In the case of manufacturing a liquid crystal element of the TN type, the STN type, the IPS type, or the FFS type, a process of imparting a liquid crystal alignment ability to the coating film formed in the above-described Step 1 (alignment treatment) is performed. Thus, the liquid crystal molecules are imparted with an alignment ability to the coating film to become a liquid crystal alignment film. As the alignment treatment, rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton or the like, or photo-alignment treatment in which the coating film is subjected to light irradiation to impart a liquid crystal alignment ability is preferably used. In the case of manufacturing a liquid crystal element of the vertical alignment type, the coating film formed in the above-described Step 1 can be directly used as a liquid crystal alignment film, and the alignment treatment can also be performed on the coating film in order to further improve the liquid crystal alignment ability.

[0213] The light irradiation in the photo-alignment treatment can be performed by a method of irradiating the coating film after the post-baking step, a method of irradiating the coating film after the pre-baking step and before the post-baking step, or a method of irradiating the coating film during the heating of the coating film in at least either of the pre-baking step and the post-baking step. In the photo-alignment treatment, as the radiation to be irradiated to the coating film, for example, ultraviolet rays and visible rays including light having a wavelength of 150 nm to 800 nm can be used. Ultraviolet rays including light having a wavelength of 200 nm to 400 nm are preferred. In the case where the radiation is polarized, it can be linearly polarized or partially polarized. In the case where the radiation to be used is linearly polarized or partially polarized, the irradiation can be performed from a direction perpendicular to the surface of the substrate, from an inclined direction, or a combination thereof. In the case where the radiation is not polarized, the irradiation direction is preferably an inclined direction.

[0214] As the light source to be used, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used. The irradiation amount of the radiation is preferably 400 J / m 2 to 20,000 J / m 2 , more preferably 1,000 J / m 2 to 5,000 J / m 2 . In order to improve the reactivity, the light irradiation to the coating film can be performed while the coating film is being heated. In addition, a step of bringing the organic film subjected to the light irradiation treatment into contact with water, a water-soluble organic solvent, or a mixed solvent of water and a water-soluble organic solvent can also be included.

[0215] (Step 3: Construction of Liquid Crystal Cell)

[0216] Two substrates each having a liquid crystal alignment film formed thereon in the above-described manner are prepared, and a liquid crystal is disposed between the two substrates disposed facing each other, whereby a liquid crystal cell is manufactured. In the manufacture of the liquid crystal cell, for example, the following methods can be mentioned: [1] a method in which two substrates are disposed facing each other with a gap (spacer) interposed therebetween, and the periphery of the two substrates is bonded using a sealant, liquid crystal is injected and filled into a cell gap defined by the surfaces of the substrates and the sealant, and then the injection hole is sealed; [2] a method (one drop filling (ODF) method) in which a sealant is applied to a prescribed site on one of the substrates having a liquid crystal alignment film formed thereon, liquid crystal is further dropped at prescribed sites on the surface of the liquid crystal alignment film, and then the other substrate is bonded facing the liquid crystal alignment film, and the liquid crystal is allowed to spread over the entire surface of the substrate. For the manufactured liquid crystal cell, a treatment of heating to a temperature at which the liquid crystal used attains an isotropic phase, and then slowly cooling to room temperature is preferably further performed, whereby the flow alignment at the time of filling of the liquid crystal is removed.

[0217] As the sealant, for example, a hardening agent and an epoxy resin containing alumina balls as spacers, etc. can be used. As the spacers, photospacers, bead spacers, etc. can be used.

[0218] As the liquid crystal used, nematic liquid crystal, smectic liquid crystal, etc. can be exemplified, of which nematic liquid crystal is preferable. As the nematic liquid crystal, for example, Schiff base-based liquid crystal, azoxy-based liquid crystal, biphenyl-based liquid crystal, phenylcyclohexane-based liquid crystal, ester-based liquid crystal, terphenyl-based liquid crystal, biphenylcyclohexane-based liquid crystal, pyrimidine-based liquid crystal, dioxane-based liquid crystal, bicyclooctane-based liquid crystal, cubane-based liquid crystal, etc. can be used. In addition, for example, cholesteric liquid crystal, chiral reagent, ferroelectric liquid crystal, etc. can be added to these liquid crystals and used.

[0219] In the PSA mode, the following treatment is performed: a polymerizable compound (for example, a multifunctional (meth)acrylate compound, etc.) is filled into the cell gap together with the liquid crystal, and after the liquid crystal cell is constructed, light is irradiated to the liquid crystal cell in a state where a voltage is applied between the conductive films possessed by the pair of substrates. In the production of a liquid crystal element of the PSA mode, the use ratio of the polymerizable compound is 0.01 parts by mass to 3 parts by mass, preferably 0.1 parts by mass to 1 parts by mass, with respect to 100 parts by mass of the total of the liquid crystal.

[0220] Subsequently, a polarizing plate is attached to the outer surface of the liquid crystal cell as necessary. As the polarizing plate, a polarizing plate in which a polarizing film called an "H film" that is obtained by extending and orienting polyvinyl alcohol and absorbing iodine is sandwiched by a cellulose acetate protective film or a polarizing plate including the H film itself can be exemplified. Thereby, a liquid crystal element is obtained.

[0221] The liquid crystal element of the present disclosure can be effectively applied to various uses. Specifically, for example, it can be used in a clock, a portable game machine, a word processor, a notebook personal computer, a car navigation system, a video camera, a personal digital assistant (PDA), a digital camera, a mobile phone, a smartphone, various monitors, a liquid crystal television, an information display, etc. various display devices, or a dimming film, etc. In addition, the liquid crystal element formed using the liquid crystal aligning agent of the present disclosure can also be applied to an optical film such as a phase difference film.

[0222] [Examples]

[0223] Hereinafter, specific description will be made by Examples, but the content of the present disclosure is not limited to the following Examples.

[0224] In the following examples, the weight average molecular weight (Mw), the number average molecular weight (Mn), and the molecular weight distribution (Mw / Mn) of the polymer were measured by the following methods.

[0225] <Weight average molecular weight, number average molecular weight, and molecular weight distribution>

[0226] Mw and Mn were measured by gel permeation chromatography (GPC) under the following conditions. In addition, the molecular weight distribution (Mw / Mn) was calculated from the obtained Mw and Mn.

[0227] Apparatus: "GPC-101" by Showa Denko K.K.

[0228] GPC column: combination of "GPC-KF-801", "GPC-KF-802", "GPC-KF-803", and "GPC-KF-804" manufactured by Shimadzu GLC, K.K.

[0229] Mobile phase: tetrahydrofuran (THF)

[0230] Column temperature: 40°C

[0231] Flow rate: 1.0 mL / min

[0232] Sample concentration: 1.0 mass%

[0233] Sample injection amount: 100 μL

[0234] Detector: differential refractometer

[0235] Standard substance: monodisperse polystyrene

[0236] The following shows the compounds used in the following examples. Furthermore, the following, for the sake of convenience, there are cases where the "compound represented by formula (X)" is simply represented as "compound (X)".

[0237] (Reactive compound)

[0238] [Chemical 30]

[0239]

[0240] [Chemical 31]

[0241]

[0242] (Monomer containing anhydride group)

[0243] [Chem. 32]

[0244]

[0245] (Monomer providing structural unit U2)

[0246] [Chem. 33]

[0247]

[0248] (Monomer providing structural unit U3)

[0249] [Chem. 34]

[0250]

[0251] (Other monomers)

[0252] [Chem. 35]

[0253]

[0254] (Tetracarboxylic dianhydride)

[0255] [Chem. 36]

[0256]

[0257] (Diamine)

[0258] [Chem. 37]

[0259]

[0260] [Chem. 38]

[0261]

[0262] (Additive)

[0263] [Chem. 39]

[0264]

[0265] [Chem. 40]

[0266]

[0267] <Synthesis of monomers>

[0268] [Synthesis Example 1-1: Synthesis of compound (E-3)]

[0269] Compound (E-3) was synthesized according to the following scheme.

[0270] [Chem. 41]

[0271]

[0272] In a 500 ml three-necked flask equipped with a stirrer, tert-butyl 4-(2- hydroxyethyl)benzylcarbamate 15.0 g, l-(4-fluorophenyl)-2-hydroxy-2- methylpropan-l-one 12.0 g, potassium carbonate 9.1 g, N,N-dimethylformamide 300 mL were added, and stirred at room temperature for 30 minutes. After confirming dissolution of the starting materials, the reaction was carried out at 80°C for 12 hours. After the reaction, the reaction solution was poured into distilled water 1500 mL, and the precipitated solid was collected by filtration. The solid was then dried under vacuum and recrystallized, thereby obtaining 16.7 g of the intermediate.

[0273] After stirring for 1 hour, the reaction solution was dissolved in a THF / ethyl acetate mixed solution, and subjected to two liquid-liquid separations using sodium bicarbonate and three liquid-liquid separations using water. The organic layer was dried after removing the solvent by distillation, thereby obtaining 10.5 g of the compound (E-3).

[0274] [Synthesis Example 1-2: Synthesis of compound (E-14)]

[0275] The compound (E-14) was synthesized according to the following scheme.

[0276] [Compound 42]

[0277]

[0278] In Synthesis Example 1-1, tert-butyl (4-fluorobenzyl)carbamate and 4-(4- pentylcyclohexyl)phenol were used instead of tert-butyl 4-(2-hydroxyethyl)benzylcarbamate and l-(4-fluorophenyl)-2-hydroxy-2-methylpropan-l-one, respectively, and otherwise, 9.7 g of the compound (E-14) was obtained by the same method as in Synthesis Example 1-1. In addition, tert-butyl (4-fluorobenzyl)carbamate was synthesized according to the method described in Tetrahedron, 2001, 57, 2965-2972.

[0279] [Synthesis Example 1-3: Synthesis of compound (E-15)]

[0280] The compound (E-15) was synthesized according to the following scheme.

[0281] [Compound 43]

[0282]

[0283] To (E)-3-(4-(4'-pentyl-[1,1'-bi(cyclohexane)]-4-yl)phenyl)acrylic acid 31.4 g was added thionyl chloride 200 ml with a catalytic amount of dimethyl formamide (DMF) and reacted at 60°C for 2 hours. After the reaction, the thionyl chloride was distilled off under reduced pressure. The obtained solid was dissolved in dehydrated THF 20 ml to make solution A. On the other hand, tert-butyl (2-hydroxyethyl)carbamate 13.2 g (82.0 mmol) and triethylamine 5.00 g were dissolved in dehydrated THF 100 ml and cooled to 0°C with an ice bath. Solution A was added dropwise thereto and reacted at room temperature for one night. After the reaction, the reaction liquid was subjected to two liquid-liquid separations with 1 equivalent concentration of hydrochloric acid, three liquid-liquid separations with water, and the organic layer was distilled off under reduced pressure. Thereby, a Boc-protected intermediate was obtained. After tri fluoroacetic acid 100 ml was added thereto and stirred for 1 hour, it was dissolved in a THF / ethyl acetate mixed solution, subjected to two liquid-liquid separations with sodium bicarbonate, three liquid-liquid separations with water. After the organic layer was subjected to solvent distillation and dried, compound (E-15) was obtained.

[0284] [Synthesis Example 1-4, Synthesis Example 1-5: Synthesis of compound (E-16), compound (E-17)]

[0285] The intermediates of compound (E-16), compound (E-17) were synthesized according to the methods described in the following literatures, respectively. In Synthesis Example 1-3, each intermediate was used instead of (E)-3-(4-(4'-pentyl-[1,1'-bi(cyclohexane)]-4-yl)phenyl)acrylic acid, and otherwise, compound (E-16) and compound (E-17) were obtained by the same method as Synthesis Example 1-3.

[0286] Intermediate of compound (E-16): Molecular Crystals and Liquid Crystals, 2017, 650, 32-45

[0287] Intermediate of compound (E-17): Angewandte Chemie International Edition, 2009, 48, 3494-3498

[0288] [Synthesis Example 1-6: Synthesis of compound (E-18)]

[0289] [Compound 44]

[0290]

[0291] To sodium hydride 4.8 g, a solution of triethyl phosphonoacetate 30.2 g in dry THF 200 ml was added dropwise at 0°C and stirred for 2 hours. To this, a solution of 4-acetylphenyl 4-(4-cyanobutoxy)benzoate 33.7 g in THF 100 ml was added dropwise at room temperature and stirred for 1 hour, and then the reaction was carried out with reflux for 2 hours. After the completion of the reaction, ethyl acetate 300 ml was added, and the mixture was subjected to liquid separation twice with saturated NH4Cl solution and liquid separation three times with water. The organic layer was subjected to solvent distillation with a rotary evaporator, and then stirred with water 300 ml and sodium hydroxide 10 g at reflux for 3 hours. After the stirring, the pH was adjusted to 4 with hydrochloric acid, and the precipitated solid was filtered, washed with water, and dried to obtain 30.9 g of the intermediate.

[0292] In Synthesis Example 1-3, the intermediate was used instead of (E)-3-(4-(4'-pentyl-[l, l'-bi(cyclohexane)]-4-yl)phenyl)acrylic acid, and otherwise, the compound (E-18) was obtained by the same method as in Synthesis Example 1-3.

[0293] [Synthesis Example 1-7: Synthesis of compound (E-20)]

[0294] The compound (E-20) was synthesized according to the following scheme.

[0295] [Compound 45]

[0296]

[0297] In a 500-ml three-necked flask equipped with a stirrer, 4-(4-pentylcyclohexyl)phenol 10.0 g, 1-fluoro-4-nitrobenzene 9.8 g, potassium carbonate 6.2 g, and N,N-dimethylformamide 200 ml were stirred at room temperature for 30 minutes. After confirming the dissolution of the starting materials, the reaction was carried out at 80°C for 12 hours. After the reaction, the reaction solution was poured into distilled water 1500 ml, and the precipitated solid was filtered. The solid was then dried in vacuo and recrystallized to obtain 15.2 g of the intermediate.

[0298] Subsequently, the intermediate 12.0 g, 5% palladium-carbon 2.09 g, tetrahydrofuran 60 ml, and ethanol 60 ml were added to a 500-ml three-necked flask equipped with a stirrer, and heated to 80°C. To this, hydrazine monohydrate 9.81 g was added dropwise, and heating reflux was carried out for 6 hours. After cooling to room temperature, the filtered solution was reprecipitated with water 600 ml. The obtained solid was filtered, washed with water, and dried in vacuo to obtain 10.1 g of the compound (E-20).

[0299] < Synthesis of polymer >

[0300] [Synthesis Example 2-1]

[0301] Under nitrogen, a 100 mL two-necked flask was charged with 20 parts by mole of compound (A-1), 30 parts by mole of compound (B-1), 10 parts by mole of compound (B-2), 30 parts by mole of compound (C-1), and 10 parts by mole of compound (D-1) as polymerization monomers, 2 parts by mole of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, and 50 mL of tetrahydrofuran as a solvent, relative to 100 parts by mole of the polymerization monomers, and polymerized at 70°C for 6 hours. Further, the polymerization reaction was performed with the total moles of the polymerization monomers set to 50 mmol. After reprecipitation in n-hexane, the precipitate was filtered and vacuum-dried at room temperature for 8 hours, whereby the target polymer (P-1) was obtained. 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.

[0302] [Synthesis Example 2-2 to Synthesis Example 2-5, Synthesis Example 2-10, Synthesis Example 2-11]

[0303] The polymerization was performed in the same manner as in Synthesis Example 2-1, except that the polymerization monomers were set to the kinds and molar ratios shown in Table 1, whereby each of the polymers (P-2) to (P-5), (P-10), and (P-11) having the same weight average molecular weight and molecular weight distribution as the polymer (P-1) was obtained. Further, the total moles of the polymerization monomers were set to 50 mmol in the same manner as in Synthesis Example 2-1. The values in Table 1 represent the input amount (mole %) of each monomer relative to all the monomers used in the synthesis of the polymer.

[0304] [Synthesis Example 2-6]

[0305] Under nitrogen, a 100 mL two-necked flask was charged with 20 parts by mole of compound (A-1), 30 parts by mole of compound (B-1), 10 parts by mole of compound (B-2), 30 parts by mole of compound (C-1), and 10 parts by mole of compound (D-1) as polymerization monomers, 2 parts by mole of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, and 50 mL of tetrahydrofuran as a solvent, relative to 100 parts by mole of the polymerization monomers, and polymerized at 70°C for 6 hours. Further, the polymerization reaction was performed with the total moles of the polymerization monomers set to 50 mmol. After reprecipitation in n-hexane, the precipitate was filtered and vacuum-dried at room temperature for 8 hours, whereby the target polymer (P-1) was obtained. 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.

[0306] [Synthesis Example 2-7]

[0307] The polymerization was performed in the same manner as in Synthesis Example 2-6 except that the kinds and molar ratios of the polymerization monomers were as shown in Table 1, and the total molar number of the polymerization monomers was set to 20 mmol, to obtain a polymer (P-7) having a weight average molecular weight and a molecular weight distribution equivalent to those of the polymer (P-6).

[0308] [Synthesis Example 2-8]

[0309] In a 100-ml two-necked flask, 70 parts by mole of compound (A-6) and 30 parts by mole of compound (B-4) were placed as polymerization monomers, 50 ml of toluene was placed as a solvent, and 0.2 parts by mole of bis(cyclopentadienyl)zirconium dichloride and 0.003 parts by mole of methyl aluminoxane were placed as a polymerization catalyst, and the polymerization was performed at room temperature for 1 hour under nitrogen. The total molar number of the polymerization monomers was set to 50 mmol. After reprecipitation was performed in an acidic methanol solution, the precipitate was dissolved in NMP, and reprecipitation was performed again in an acidic methanol solution. The precipitate was 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 was 111,200, and the molecular weight distribution Mw / Mn was 3.12.

[0310] [Synthesis Example 2-9]

[0311] The polymerization was performed in the same manner as in Synthesis Example 2-8 except that the kinds and molar ratios of the polymerization monomers were as shown in Table 1, and the total molar number of the polymerization monomers was set to 50 mmol, to obtain a polymer (P-9) having a weight average molecular weight and a molecular weight distribution equivalent to those of the polymer (P-8).

[0312] [Table 1]

[0313]

[0314] [Synthesis Example 3-1]

[0315] To the polymer (P-1) obtained by Synthesis Example 2-1, 10 parts by mole of compound (E-1) and 10 parts by mole of compound (E-14) were added with respect to the total amount of the monomer input. Then, 30 parts by mole of dimethyl formamide-dimethyl acetal (DMF-DMA) was added as an esterification agent, and heating was performed at 60°C for 3 hours. Thereafter, reprecipitation was performed on the obtained solution with water, to obtain the target polymer (P-12).

[0316] [Synthesis Example 3-2 to Synthesis Example 3-15]

[0317] The polymer (base resin) and the reactive compound to be reacted were set to the kinds and molar ratios shown in Table 2, and polymerization was performed in the same manner as in Synthesis Example 3-1, except that the esterification reaction was not performed using an esterification agent, to obtain each of the polymers (P-27) and (P-28) having the same weight average molecular weight and molecular weight distribution as the polymer (P-12).

[0318] [Synthesis Example 3-16, Synthesis Example 3-17]

[0319] The polymer (base resin) and the reactive compound to be reacted were set to the kinds and molar ratios shown in Table 2, and polymerization was performed in the same manner as in Synthesis Example 3-1, except that the esterification reaction was not performed using an esterification agent, to obtain each of the polymers (P-27) and (P-28) having the same weight average molecular weight and molecular weight distribution as the polymer (P-12).

[0320] [Table 2]

[0321]

[0322] [Synthesis Example 4-1]

[0323] A compound (TA-1) of 100 mol as a tetracarboxylic dianhydride, and a compound (DA-1) of 30 mol, a compound (DA-8) of 50 mol, and a compound (DA-9) of 20 mol as diamines were dissolved in N-methyl-2-pyrrolidone (NMP) of 170 g, and a reaction was performed at 40°C for 24 hours, whereby a solution containing a polyamic acid of 20 mass% was obtained. Subsequently, NMP was added to the obtained polyamic acid solution, and pyridine and acetic anhydride each of 1.80 mol equivalent with respect to the carboxyl group derived from the tetracarboxylic dianhydride possessed by the polyamic acid were added, and a dehydration ring closure reaction was performed at 80°C for 4 hours. After the dehydration ring closure reaction, solvent replacement was performed on the solvent in the system with fresh NMP, and concentration was further performed, whereby a solution containing a polyimide (which was set as a polymer (PI-1)) of 15 mass% and having an imidization rate of 70% was obtained. A small amount of this solution was separated, NMP was added to make a solution of 10 mass%, and the solution viscosity of the solution obtained by measurement of this solution was 43.7 mPa-s.

[0324] Subsequently, the obtained polymer solution was injected into a large excess of methanol, and the reaction product was precipitated. The precipitate was washed with methanol, and dried at 40°C under reduced pressure for 15 hours, whereby a polyimide (PI-1) was obtained.

[0325] [Synthesis Example 4-2, Synthesis Example 4-3, Synthesis Example 4-5 to Synthesis Example 4-7]

[0326] The kind and amount of tetracarboxylic dianhydride and diamine used in the polymerization were changed as described in Table 3, and the polymerization was performed in the same manner as in Synthesis Example 4-1 except for this aspect, to obtain a polymer (PI-2), a polymer (PI-3), a polymer (PI-5) to a polymer (PI-7) as polyimides, respectively. In Table 3, the numerical value of tetracarboxylic dianhydride indicates the proportion (mole) of each compound with respect to 100 mole of the total amount of tetracarboxylic dianhydride used in the synthesis. The numerical value of diamine indicates the proportion (mole) of each compound with respect to 100 mole of the total amount of diamine used in the synthesis.

[0327] [Synthesis Example 4-4]

[0328] 100 mole of a compound (TA-1) as tetracarboxylic dianhydride, 30 mole of a compound (DA-1) as diamine, 50 mole of a compound (DA-3), and 20 mole of a compound (DA-9) were dissolved in 170 g of NMP, and a reaction was performed at 60°C for 8 hours, to thereby obtain a solution containing 20 mass% of polyamic acid. The solution viscosity was 707 mPa-s.

[0329] [Synthesis Example 4-8, Synthesis Example 4-9]

[0330] The kind and amount of tetracarboxylic dianhydride and diamine used in the polymerization were changed as described in Table 3, and the polymerization was performed in the same manner as in Synthesis Example 4-4 except for this aspect, to obtain a polymer (PI-8), a polymer (PI-9) as polyamic acid, respectively.

[0331] [Table 3]

[0332]

[0333] [Example 1: PSA-type liquid crystal display element]

[0334] (1) Preparation of liquid crystal alignment agent (AL-1)

[0335] 100 parts by mass of the polymer (PI-1) obtained in Synthesis Example 4-1 was added with 10 parts by mass of the polymer (P-12) obtained in Synthesis Example 3-1, and NMP and butyl cellosolve (BC) as a solvent, to prepare a solution having a solvent composition of NMP / BC = 50 / 50 (mass ratio) and a solid content concentration of 4.0 mass%. The solution was filtered using a filter having a pore size of 0.2 μm, to thereby prepare a liquid crystal alignment agent (AL-1).

[0336] (2) Preparation of liquid crystal composition

[0337] To 10 g of a nematic liquid crystal (manufactured by Merck Co., Ltd., MLC-6608), 5 mass% of a liquid crystalline compound represented by the following formula (L1-1) and 0.3 mass% of a photopolymerizable compound represented by the following formula (L2-1) were added and mixed, to obtain a liquid crystal composition LC1.

[0338] [Chemical Formula 46]

[0339]

[0340] (3) Manufacture of PSA-type liquid crystal display element

[0341] The liquid crystal alignment agent (AL-1) prepared in the above was applied to each electrode surface of two glass substrates each having a conductive film including an ITO electrode patterned into a slit shape, using a liquid crystal alignment film printer (manufactured by Japan Photo Printing Co., Ltd.), and after removing the solvent by heating (pre-baking) on a hot plate at 80°C for 2 minutes, the coating film was heated (post-baking) on a hot plate at 230°C for 30 minutes to form a coating film having an average film thickness of 100 nm. With respect to the coating film, after performing ultrasonic cleaning in ultrapure water for 1 minute, drying was performed in a clean oven at 100°C for 10 minutes, whereby a pair (two pieces) of substrates having a liquid crystal alignment film were obtained. Further, the pattern of the electrode used was the same kind of pattern as the electrode pattern in the PSA mode.

[0342] Subsequently, after applying an epoxy resin-based adhesive agent to which alumina balls having a diameter of 5.5 μm were added to the outer edge of the surface of one of the pair of substrates having a liquid crystal alignment film, the adhesive agent was hardened by overlapping and pressure-bonding in a manner such that the liquid crystal alignment film surfaces were opposed to each other. Subsequently, after filling the liquid crystal composition LC1 prepared in the above between the pair of substrates from a liquid crystal injection port, the liquid crystal injection port was sealed with an acrylic-based photo-hardening adhesive agent, whereby a liquid crystal cell was manufactured. Then, while applying an alternating current of 10 V at a frequency of 60 Hz between the conductive films of the liquid crystal cell in a state of liquid crystal driving, ultraviolet rays were irradiated using an ultraviolet ray irradiation device using a metal halide lamp as a light source at an irradiation amount of 100,000 J / m2. Further, the irradiation amount was a value determined using a light meter measured on the basis of a wavelength of 365 nm. Then, polarizing plates were attached to the outer sides of both surfaces of the substrates in a manner such that the polarizing directions of the polarizing plates were orthogonal to each other and the optical axes of the ultraviolet rays of the liquid crystal alignment film were at an angle of 45° in the projection direction of the surface of the substrate, whereby a PSA-type liquid crystal display element was manufactured. 2

[0343] (4) Evaluation of electrical characteristics based on voltage holding ratio (VHR)

[0344] ​For the PSA type liquid crystal display element produced in the above, the voltage retention rate 167 milliseconds after the application was measured after applying a voltage of 5 V for 60 microseconds and a span of 167 milliseconds. The measuring device used was VHR-1 manufactured by TOYO Technica Co., Ltd. At this time, in the case where the voltage retention rate was 98% or more, it was rated "good (O)", in the case where it was 95% or more but less than 98%, it was rated "fair (Δ)", and in the case where it was less than 95%, it was rated "poor (X)". As a result, in this example, the evaluation of the electrical characteristics was "good (O)".

[0345] (5) Evaluation of electrical characteristics based on VHR after long-time baking

[0346] In the (3), the post-baking time was changed from 30 minutes to 1.5 hours, and otherwise, the PSA type liquid crystal display element was produced in the same manner as in the (3). For the PSA type liquid crystal display element produced, the voltage retention rate was measured using the same conditions as in the (4). At this time, in the case where the voltage retention rate was 95% or more, it was rated "good (O)", in the case where it was 90% or more but less than 95%, it was rated "fair (Δ)", and in the case where it was less than 90%, it was rated "poor (X)". Further, the higher the VHR after long-time baking, the less likely it is to generate impurities due to post-baking. As a result, in this example, the evaluation of the electrical characteristics after long-time baking was "good (O)".

[0347] (6) Evaluation of long-term heat resistance

[0348] The PSA type liquid crystal cell was produced in the same manner as in the (3) without attaching polarizing plates to both outer sides of the substrate. For the PSA type liquid crystal cell, the voltage retention rate was measured in the same manner as in the (4). Further, the voltage retention rate was measured again after the obtained liquid crystal cell was stored in a constant-temperature bath at 100°C for 21 days (about 500 hours). In the case where the decrease in the voltage retention rate due to storage in the constant-temperature bath at 100°C (voltage retention rate (%) after production of the liquid crystal cell - voltage retention rate (%) after storage in the constant-temperature bath) was less than 10%, it was rated "excellent (◎)", in the case where it was 10% or more but less than 20%, it was rated "good (O)", in the case where it was 20% or more but less than 40%, it was rated "fair (Δ)", and in the case where it was 40% or more, it was rated "poor (X)". As a result, in this example, the evaluation was "good (O)".

[0349] (7) Evaluation of AC afterimage characteristics (evaluation of thin film)

[0350] In the (3), the average film thickness of the coated film was changed from 100 nm to 30 nm, and no polarizing plate was attached to the outer sides of both faces of the substrate, and otherwise, similarly to the (3), a PSA type liquid crystal cell was produced. With respect to the produced liquid crystal cell, the pretilt angle (initial pretilt angle θini) before application of a voltage to the liquid crystal cell, and the pretilt angle (post-driving pretilt angle θac) after driving for 30 hours at AC 9 V and room temperature were measured by a rotation crystallization method using a He-Ne laser according to the method described in "T. J. Scheffer et. al., Journal of Applied Physics, J. Appl. Phys. vol 48, p 1783 (1977)", and "F. Nakano et. al., Japanese Journal of Applied Physics, JPN. J. Appl. Phys. vol. 19, p 2013 (1980)". In addition, the pretilt angle change rate β [%] was calculated by the following equation (y). The pretilt angle change rate β was evaluated as "good (O)" when it was not more than 3%, as "acceptable (Δ)" when it was more than 3% and not more than 5%, and as "poor (X)" when it was more than 5%.

[0351] Pretilt angle change rate β [%] = (θac - θini) / θini x 100... (y)

[0352] [Examples 2 to 7, Example 9, Example 10, Example 15, and Comparative Examples 1 to 3]

[0353] The formulation composition was changed as shown in Table 4, and otherwise, liquid crystal alignment agents (AL-2) to (AL-7), (AL-9), (AL-10), (AL-15) to (AL-18) were produced in the same solvent composition and solid content concentration as in Example 1. In addition, using each liquid crystal alignment agent, a PSA type liquid crystal display element was produced and various evaluations were performed, similarly to Example 1. The evaluation results are shown in Table 4.

[0354] [Example 8: Light perpendicular type liquid crystal display element]

[0355] (1) Production of liquid crystal alignment agent

[0356] To 100 parts by mass of the polymer (PI-8) obtained in Synthesis Example 4-8, 10 parts by mass of the polymer (P-19) obtained in Synthesis Example 3-8, 5 parts by mass of the compound (Add-5), and NMP and BC as solvents were added to prepare a solution having 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 having a pore size of 0.2 μm, thereby preparing a liquid crystal aligning agent (AL-8).

[0357] (2) Manufacture of the optically perpendicular liquid crystal display element

[0358] The liquid crystal aligning agent (AL-8) prepared in the above (1) was applied to the transparent electrode surface of a glass substrate with a transparent electrode including an ITO film using a spinner, and after pre-baking using a hot plate at 80°C for 1 minute, main baking was performed at 200°C for 40 minutes to form a coating film having a film thickness of 0.08 μm. Subsequently, using a Hg-Xe lamp and a glan-taylor prism, polarized ultraviolet rays including a bright line at 313 nm were irradiated at 200 J / m2from a direction inclined at 40° with respect to the normal line of the substrate surface to the surface of the coating film at room temperature. 2 The same operation was repeated to prepare a pair (two pieces) of substrates on which liquid crystal aligning films were formed.

[0359] To the outer periphery of the surface of one of the two substrates on which liquid crystal aligning films were formed, an epoxy resin adhesive to which alumina balls having a diameter of 3.5 μm were added was applied by screen printing, and the pair of substrates was then pressure-bonded with the liquid crystal aligning film surfaces facing each other in such a manner that the projection direction of the optical axis of the ultraviolet rays irradiated to each substrate on the substrate surface became antiparallel. The adhesive was thermally cured at 150°C for 1 hour. Subsequently, after a liquid crystal composition (manufactured by Merck Ltd., MLC-6608) was filled into the gap between the substrates from the liquid crystal injection port, the liquid crystal injection port was sealed with an epoxy-based adhesive to obtain a liquid crystal cell. Furthermore, in order to remove the flow alignment at the time of liquid crystal injection, the liquid crystal cell was heated at 150°C and then slowly cooled to room temperature. Subsequently, polarizing plates were attached to the outer sides of both of the substrates in the liquid crystal cell in such a manner that the polarizing directions thereof were orthogonal to each other and the projection direction of the optical axis of the ultraviolet rays irradiated at the time of formation of the liquid crystal aligning film on the substrate surface was at an angle of 45°, thereby manufacturing an optically perpendicular liquid crystal display element.

[0360] (3) Evaluation

[0361] For the liquid crystal display element of the (2), evaluation of the electrical characteristics based on the voltage holding ratio (VHR) was performed in the same manner as in Example 1. In addition, in the same manner as in Example 1, evaluation of the electrical characteristics based on the VHR after long-time baking, evaluation of the long-term heat resistance, and evaluation of the AC image sticking characteristics (thin film evaluation) were performed. The evaluation results are shown in Table 4.

[0362] [Examples 11 to 13]

[0363] The formulation composition was changed as shown in Table 4, and liquid crystal alignment agents (AL-11) to (AL-13) were prepared in the same solvent composition and solid content concentration as in Example 8 except for this aspect. In addition, using each of the liquid crystal alignment agents, a homeotropic liquid crystal display element and a homeotropic liquid crystal cell were produced in the same manner as in Example 8, and various evaluations were performed. The evaluation results are shown in Table 4.

[0364] [Example 14: Optical orientation FFS-type liquid crystal display element]

[0365] (1) Preparation of liquid crystal alignment agent (AL-14)

[0366] To 100 parts by mass of the polymer (PI-8) obtained in Synthesis Example 4-8, 10 parts by mass of the polymer (P-25) obtained in Synthesis Example 3-14, 5 parts by mass of the compound (Add-9), and NMP and BC as solvents were added to prepare a solution having a solvent composition of NMP / BC = 50 / 50 (mass ratio) and a solid content concentration of 4.0 mass%. The solution was filtered using a filter having a pore size of 0.2 μm, thereby preparing a liquid crystal alignment agent (AL-14).

[0367] (2) Production of optical FFS-type liquid crystal display element

[0368] A glass substrate (provided as a first substrate) on which a flat electrode (bottom electrode), an insulating layer, and a comb-tooth electrode (top electrode) were sequentially layered on one surface, and a glass substrate (provided as a second substrate) on which no electrode was provided were prepared. Subsequently, the liquid crystal alignment agent (AL-14) was applied to one of the electrode formation surface of the first substrate and the surface of the second substrate using a spinner, and heated (pre-baking) using a hot plate at 80°C for 1 minute. Thereafter, drying (post-baking) was performed in an oven at 230°C for 30 minutes under nitrogen substitution in the oven, thereby forming a coating film having an average film thickness of 0.1 μm. The obtained coating film was irradiated with ultraviolet rays including a bright line of 254 nm polarized by a straight line at 1,000 J / m2from the normal direction of the substrate using a Hg-Xe lamp. 2The coating film was then subjected to photo-alignment treatment. The irradiation amount was measured using a light meter based on the amount of light at a wavelength of 254 nm. The coating film subjected to photo-alignment treatment was then heated in a clean oven at 230°C for 30 minutes to perform heat treatment, thereby forming a liquid crystal alignment film.

[0369] Next, for one of the pair of substrates on which the liquid crystal alignment film was formed, an epoxy resin adhesive to which alumina balls having a diameter of 3.5 μm were added was applied to the outer edge of the surface on which the liquid crystal alignment film was formed by screen printing. Thereafter, the substrates were overlapped and pressure-bonded in such a manner that the projection direction of the polarizing axis at the time of light irradiation on the substrate surface became antiparallel, and the adhesive was heat-hardened at 150°C for 1 hour. Then, after a negative liquid crystal (manufactured by Merck, MLC-6608) was filled between the pair of substrates from a liquid crystal injection port, the liquid crystal injection port was sealed with an epoxy-based adhesive, thereby obtaining a liquid crystal cell. Furthermore, in order to remove the flow alignment at the time of liquid crystal injection, it was heated at 120°C and then slowly cooled to room temperature. Thereafter, polarizing plates were attached to the outer sides of both surfaces of the substrate of the liquid crystal cell, thereby obtaining a liquid crystal display element. Note that the amount of ultraviolet irradiation after post-baking was changed in the range of 100 J / m 2 ~ 10,000 J / m 2 The series of operations were performed to manufacture three or more liquid crystal display elements that differed in the amount of ultraviolet irradiation, and the liquid crystal display element that showed the exposure amount (optimum exposure amount) that exhibited the best alignment characteristics was used for the following evaluation.

[0370] (3) Evaluation

[0371] The liquid crystal display element of the light FFS type of (2) was evaluated in the same manner as in Example 1 for the electrical characteristics based on the voltage holding ratio (VHR), the electrical characteristics based on the VHR after long-term baking, and the long-term heat resistance. In addition, the AC residual image characteristics were evaluated (thin film evaluation) in accordance with the following procedure. The evaluation results are shown in Table 4.

[0372] AC residual image characteristics evaluation (thin film evaluation) of the liquid crystal cell of the light FFS type

[0373] In (2), the average film thickness of the coating film was changed from 100 nm to 30 nm, and polarizing plates were not attached to the outer sides of both surfaces of the substrate, and the light FFS type liquid crystal cell was produced in the same manner as in (2) except for the above. After the light FFS type liquid crystal cell produced was driven by applying an alternating voltage of 10 V for 30 hours, the black luminance change rate (%) represented by the following equation (b) was measured using a device in which a polarizer and an analyzer were disposed between a light source and a light amount detector.

[0374] Black luminance change rate (%) = [(β(30 hr) - β(0)) / β(0)] x 100 (b)

[0375] (In formula (b), β(0) is the minimum light transmittance of the liquid crystal display element with the driving stress interposed between the polarizer and the analyzer under the crossed Nicols. β(30 hr) is the minimum light transmittance of the liquid crystal display element with the driving stress interposed between the polarizer and the analyzer for 30 hours under the crossed Nicols.)

[0376] The AC residual image characteristics are expressed by the change rate of the black level before the driving for 30 hours with an alternating voltage and the black level after the driving for 30 hours with an alternating voltage. The smaller the change rate, the more excellent the AC residual image characteristics. The liquid crystal display element with the black luminance change rate of less than 10% is rated as "good (O)", the liquid crystal display element with the black luminance change rate of 10% or more and less than 30% is rated as "fair (Δ)", and the liquid crystal display element with the black luminance change rate of 30% or more is rated as "poor (X)". As a result, the black luminance change rate of the liquid crystal display element is 5%, and the AC residual image characteristics are rated as "good (O)".

[0377] [Table 4]

[0378]

[0379] As is apparent from the results of the above examples, the liquid crystal alignment agent of Examples 1 to 16 containing the polymer (P) is evaluated as good or excellent in the voltage retention rate after the long-time baking and the long-term heat resistance. In addition, the liquid crystal alignment agent of Examples 1 to 16 is evaluated as good or fair in the AC residual image characteristics. In particular, the liquid crystal alignment agent of Examples 1 to 15 containing the polymer (P) subjected to the esterification treatment is excellent in the AC residual image characteristics.

[0380] On the other hand, in Comparative Example 1 and Comparative Example 2 not containing the polymer (P), the liquid crystal alignment agent of Comparative Example 1 is evaluated as fair (Δ) in the voltage retention rate after the long-time baking and the long-term heat resistance. In addition, the liquid crystal alignment agent of Comparative Example 2 is evaluated as poor (X) in the long-term heat resistance and the AC residual image characteristics, and is inferior to Examples 1 to 16 in performance. Furthermore, in Comparative Example 2, the polymer (P-11) synthesized using the compound (D-3) and the compound (D-4) as the ring-opened compound of the maleimide compound is used as the polymer component of the liquid crystal alignment agent. In the polymer (P-11), the two groups bonded to the carbon-carbon double bond of the compound (D-3) and the compound (D-4) adopt the trans structure, and thus it is difficult to close the ring at the time of the post-baking, and thus it is presumed that the polymer (P-11) is inferior to Examples 1 to 16 in the voltage retention rate after the long-time baking, the long-term heat resistance, and the AC residual image characteristics.

Claims

1. A liquid crystal alignment agent comprising a polymer (P) having at least one selected from the group consisting of a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), a structural unit represented by the following formula (4), and a structural unit represented by the following formula (5), The polymer (P) comprises structural units having the structure -COOR 5 , wherein R 5 is a monovalent thermally detachable group, In formula (1) to formula (5), X 1 and X 2 are one monovalent group represented by the following formula (6) and the other is -OR 4 ; R 4 is a hydrogen atom or a monovalent hydrocarbon group having a carbon number of 1 to 10; A 1 is a methylene group, an ethylene group, a sulfur atom, or an oxygen atom; m is 1 or 2; and "*"1" indicates a bond to an atom constituting the main chain of the polymer. *-NR 1 -R 2 -R 3 (6) In formula (6), R 1 is a hydrogen atom or a monovalent hydrocarbon group having a carbon number of 1 to 10; R 2 is a linear alkanediyl group having a carbon number of 1 to 5; R 3 is at least one 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 photo-orientation group, a vertical orientation group, a photoinitiator group, an electron-transporting group, and a hole-transporting group, the basic group and the group generating a basic group by heating are a group represented by the following formula (r1-1) to formula (r1-4), respectively; the acidic group and the group generating an acidic group by heating are a group represented by the following formula (r2-1) to formula (r2-4), respectively; the crosslinkable group and the group generating a crosslinkable group by heating are a group represented by the following formula (r3-1) to formula (r3-9), respectively; the photo-orientation group is a group represented by the following formula (r4-1) to formula (r4-4), respectively; the vertical alignment group is an alkyl group having a carbon number of 3 to 30, a fluorine-containing alkyl group having a carbon number of 3 to 30, an alkoxy group having a carbon number of 3 to 30, a group represented by the following formula (r5-1) to formula (r5-7), or a group having a carbon number of 17 to 51 having a steroid skeleton; the photoinitiator group is a group represented by the following formula (r6-1) to formula (r6-11), respectively; the electron-transporting group is a group having an imidazole ring, a pyridine ring, a pyrazine ring, an oxadiazole ring, a triazine ring, a triazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, a thiadiazole ring, a quinoxaline ring, a quinoline ring, or an isoquinoline ring; the hole-transporting group is a group having an aromatic amine structure, a carbazole ring, or a thiophene ring; and "*" represents a bond. In formula (r1-1) to formula (r1-4), PG is a monovalent thermally dissociable group; and "*" represents a bond. In the formulae (r2-1) to (r2-4), R 11 is a hydrogen atom or an alkyl group; PG is a monovalent thermally dissociable group; and "*" represents a bond. In the formulae (r3-1) to (r3-9), R 12 is a hydrogen atom or an alkyl group; R 13 is a hydrogen atom or a methyl group; and "*" indicates a bond. In the formulae (r4-1) to (r4-4), R is a hydrogen atom or a monovalent organic group; X 3 is -O- or -NH-; and "*" indicates a bond. In formula (r5-1) to formula (r5-7), R is a hydrogen atom, a fluorine atom, an alkyl group having a carbon number of 1 to 20, an alkoxy group having a carbon number of 1 to 20, or a fluoroalkyl group having a carbon number of 1 to 20; and "*" represents a bond. In formula (r6-1) to formula (r6-11), R is a hydrogen atom or an alkyl group; and "*" represents a bond.

2. The liquid crystal aligning agent according to claim 1, wherein The polymer (P) contains a structural unit having a cyclic carbonate structure.

3. The liquid crystal aligning agent according to claim 1 or 2, wherein The polymer (P) contains a structural unit derived from a monomer selected from the group consisting of a compound represented by the following formula (8-1), a compound represented by the following formula (8-2), an N-substituted aromatic maleimide compound, an olefinic hydrocarbon, and a (meth)acrylic compound generating an isocyanate group by heating, In formula (8-1), R 18 is a hydrogen atom or a monovalent hydrocarbon group having a carbon number of 1 to 10; Ar 1 is a divalent aromatic ring group; 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 of 0 to 3; and r is 0 or 1.

4. The liquid crystal alignment agent according to claim 1 or 2, further comprising at least one polymer selected from the group consisting of a polyamic acid, a polyamic acid ester, and a polyimide.

5. A liquid crystal alignment film formed using the liquid crystal alignment agent according to any one of claims 1 to 4.

6. A liquid crystal element comprising the liquid crystal alignment film according to claim 5.

7. A polymer having at least one selected from the group consisting of a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), a structural unit represented by the following formula (4), and a structural unit represented by the following formula (5), The polymer comprises structural units having the structure -COOR 5 where R 5 is a monovalent thermally detachable group, In formula (1) to formula (5), X 1 and X 2 one of which is a monovalent group represented by the following formula (6), and the other is -OR 4 ; R 4 is a hydrogen atom or a monovalent hydrocarbon group having a carbon number of 1 to 10; A 1 is a methylene group, an ethylene group, a sulfur atom, or an oxygen atom; m is 1 or 2; and "*"1" indicates a bond to an atom constituting the main chain of the polymer. * -NR 1 -R 2 -R 3 (6) In formula (6), R 1 is a hydrogen atom or a monovalent hydrocarbon group having a carbon number of 1 to 10; R 2 is a linear alkanediyl group having a carbon number of 1 to 5; R 3 is at least one 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 photo-orientation group, a vertical orientation group, a photoinitiator group, an electron-transporting group, and a hole-transporting group, the basic group and the group generating a basic group by heating are represented by the following formula (r1-1) to formula (r1-4), respectively; the acidic group and the group generating an acidic group by heating are represented by the following formula (r2-1) to formula (r2-4), respectively; the crosslinkable group and the group generating a crosslinkable group by heating are represented by the following formula (r3-1) to formula (r3-9), respectively; the photo-orienting group is represented by the following formula (r4-1) to formula (r4-4), respectively; the vertical aligning group is an alkyl group having a carbon number of 3 to 30, a fluorine-containing alkyl group having a carbon number of 3 to 30, an alkoxy group having a carbon number of 3 to 30, a group represented by the following formula (r5-1) to formula (r5-7), or a group having a carbon number of 17 to 51 having a steroid skeleton; the photoinitiator group is represented by the following formula (r6-1) to formula (r6-11), respectively; the electron-transporting group is a group having an imidazole ring, a pyridine ring, a pyrazine ring, an oxadiazole ring, a triazine ring, a triazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, a thiadiazole ring, a quinoxaline ring, a quinoline ring, or an isoquinoline ring; the hole-transporting group is a group having an aromatic amine structure, a carbazole ring, or a thiophene ring; and "*" represents a bond. In formula (r1-1) to formula (r1-4), PG is a monovalent thermally dissociable group; and "*" represents a bond. In the formulae (r2-1) to (r2-4), R 11 is a hydrogen atom or an alkyl group; PG is a monovalent thermally dissociable group; and "*" represents a bond. In the formulae (r3-1) to (r3-9), R 12 is a hydrogen atom or an alkyl group; R 13 is a hydrogen atom or a methyl group; and "*" indicates a bond. In the formulae (r4-1) to (r4-4), R is a hydrogen atom or a monovalent organic group; X 3 is -O- or -NH-; and "*" indicates a bond In formula (r5-1) to formula (r5-7), R is a hydrogen atom, a fluorine atom, an alkyl group having a carbon number of 1 to 20, an alkoxy group having a carbon number of 1 to 20, or a fluoroalkyl group having a carbon number of 1 to 20; and "*" represents a bond. In formula (r6-1) to formula (r6-11), R is a hydrogen atom or an alkyl group; and "*" represents a bond.

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