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

Abstract

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

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal device. [Background technology]

[0002] Liquid crystal elements are used in a wide range of applications, from relatively large display devices such as LCD televisions and information displays to small display devices such as smartphones. The performance of liquid crystal elements is determined by various characteristics such as the alignment of the liquid crystal, the magnitude of the pretilt angle, and the voltage holding ratio. To improve the performance of liquid crystal elements, improvements have been made not only to the liquid crystal materials but also to the liquid crystal alignment film for aligning the liquid crystal in a certain direction.

[0003] In liquid crystal devices, if electric charge accumulates in the liquid crystal cells, it can be perceived by the viewer as an afterimage (DC afterimage), which can reduce the display quality of the liquid crystal device. Therefore, one of the properties required for liquid crystal alignment films is low electric charge accumulation.

[0004] Therefore, various techniques have been proposed to suppress the accumulation of charges in liquid crystal cells and improve the display quality of liquid crystal elements (see, for example, Patent Document 1). Patent Document 1 discloses that the accumulation of charges is reduced by incorporating a polyamic acid obtained by reacting a diamine compound containing a nitrogen-containing diamine such as N4,N4'-bis(4-aminophenyl)-benzidine with a tetracarboxylic dianhydride into a liquid crystal aligning agent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-107811 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, with the trend toward higher resolution liquid crystal elements, the quality requirements for liquid crystal elements have become even stricter. Therefore, it is necessary to minimize the charge accumulated in the liquid crystal element due to the application of voltage, minimize the occurrence of image retention, and achieve high transmittance for the liquid crystal element. Furthermore, in consideration of the application of rubbing methods, improvement of liquid crystal alignment and voltage holding ratio, and suppression of yield reduction, the organic film formed using the liquid crystal alignment agent must have sufficiently high strength.

[0007] During the manufacturing process of liquid crystal alignment films and liquid crystal elements, the application of heat or light to the liquid crystal alignment film or the organic film that will become the liquid crystal alignment film can result in the generation of decomposition products such as polymers. Furthermore, the generation of such thermal decomposition products or photodecomposition products can cause display defects (bright spots) in the resulting liquid crystal elements. To further improve the quality of liquid crystal elements, it is necessary to suppress the generation of such bright spots.

[0008] The object of the present invention is to provide a liquid crystal aligning agent that can form a liquid crystal alignment film with high mechanical strength, is less likely to produce afterimages due to the accumulation of residual charges, has fewer bright spots, and can provide a liquid crystal element with high transmittance. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by using a diamine having a specific structure, and have thus completed the present invention. Specifically, the present invention provides the following means.

[0010] <1> A liquid crystal aligning agent comprising a polymer (P) having a structural unit derived from a compound represented by the following formula (1): [ka] (In formula (1), Ar 1 is a divalent aromatic ring group. 1 is a single bond, -O-, -S- or -NR 1 -R 1is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally detachable group. 2 , Ar 3 and Y 1 meets the following requirements (i), (ii), or (iii): 1 If is a single bond, Y 1 is a carbon atom and Ar 1 is bonded to. (i)Ar 2 is a divalent aromatic ring group. 3 is a monovalent aromatic ring group. 1 is a divalent organic group having one or more carbon atoms. (ii) Ar 2 and Ar 3 are combined together, Ar 2 and Ar 3 represents a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which Y is bonded. 1 is a divalent organic group having one or more carbon atoms. (iii) Ar 2 is a divalent aromatic ring group. 3 and Y 1 are combined together, Ar 3 and Y 1 is a divalent group containing a nitrogen-containing aromatic fused ring structure formed together with the nitrogen atom to which

[0011] <2> the above <1> A liquid crystal alignment film formed using the liquid crystal alignment agent of the above. <3> the above <2> A liquid crystal element comprising a liquid crystal alignment film. [Effects of the Invention]

[0012] According to the liquid crystal aligning agent of the present invention, a liquid crystal alignment film having high mechanical strength can be formed, and a liquid crystal device having high transmittance and being less susceptible to afterimages and bright spots can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0013] Liquid crystal alignment agent Hereinafter, each component contained in the liquid crystal aligning agent of the present disclosure and other components that may be arbitrarily blended as necessary will be described.

[0014] In this specification, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The term "chain hydrocarbon group" refers to a linear hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure in the main chain and is composed solely of a chain structure. However, chain hydrocarbon groups may be saturated or unsaturated. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. However, the alicyclic hydrocarbon group does not necessarily have to be composed solely of an alicyclic hydrocarbon structure and may also contain a chain structure as part of it. The term "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, the aromatic hydrocarbon group does not necessarily have to be composed solely of an aromatic ring structure and may contain a chain structure or an alicyclic hydrocarbon structure as part of it. The term "aromatic ring" includes aromatic hydrocarbon rings and aromatic heterocycles. The term "organic group" refers to an atomic group formed by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound).

[0015] The "main chain" of a polymer refers to the "trunk" portion of the polymer, which is the longest chain of atoms. It is permissible for this "trunk" portion to contain a ring structure. For example, "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. A "side chain" refers to a portion branched from the "trunk" of the polymer. "Tetracarboxylic acid derivative" is intended to include tetracarboxylic acid dianhydrides, tetracarboxylic acid diesters, and tetracarboxylic acid diester dihalides.

[0016] The liquid crystal aligning agent of the present disclosure contains a polymer (P) having a structural unit derived from a compound represented by the following formula (1) (hereinafter also referred to as a "specific diamine"). [ka] (In formula (1), Ar 1 is a divalent aromatic ring group. 1 is a single bond, -O-, -S- or -NR 1 -R 1is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally detachable group. 2 , Ar 3 and Y 1 meets the following requirements (i), (ii), or (iii): 1 If is a single bond, Y 1 is a carbon atom and Ar 1 is bonded to. (i)Ar 2 is a divalent aromatic ring group. 3 is a monovalent aromatic ring group. 1 is a divalent organic group having one or more carbon atoms. (ii) Ar 2 and Ar 3 are combined together, Ar 2 and Ar 3 represents a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which Y is bonded. 1 is a divalent organic group having one or more carbon atoms. (iii) Ar 2 is a divalent aromatic ring group. 3 and Y 1 are combined together, Ar 3 and Y 1 is a divalent group containing a nitrogen-containing aromatic fused ring structure formed together with the nitrogen atom to which

[0017] The polymer (P) and other components that may be optionally added are described in detail below. Unless otherwise specified, each component may be used alone or in combination of two or more.

[0018] <Polymer (P)> In the above formula (1), Ar 2 , Ar 3 and Y 1 If satisfies the above requirement (i), then Ar 1 or Ar 2The divalent aromatic ring group represented by the formula (I) is a group in which two arbitrary hydrogen atoms have been removed from the ring portion of an aromatic ring. Examples of the aromatic ring include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, an anthracene ring, and a biphenyl ring; and nitrogen-containing aromatic heterocycles such as a pyrrole ring, an imidazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a quinoline ring, an isoquinoline ring, a benzimidazole ring, a carbazole ring, and an acridine ring. Among these, Ar 1 and Ar 2 is preferably a group having a structure in which two hydrogen atoms have been removed from the ring portion of a benzene ring or a pyridine ring, and more preferably a substituted or unsubstituted phenylene group. 1 and Ar 2 A substituent other than the primary amino group may be introduced into the aromatic ring of the aromatic ring group represented by the following formula: Examples of the substituent include an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a halogen atom.

[0019] Ar 3 The monovalent aromatic ring group represented by the formula (I) is a group in which one hydrogen atom has been removed from the ring portion of an aromatic ring. Specific examples of aromatic rings include Ar 1 and Ar 2 Examples of the divalent aromatic ring group include the same groups as those exemplified in the description of the divalent aromatic ring group represented by Ar 3 is preferably a group having a structure in which one hydrogen atom has been removed from the ring moiety of a benzene ring, a naphthalene ring, or a pyridine ring, and more preferably a substituted or unsubstituted phenyl group. 3 Examples of the substituent on the ring include an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a halogen atom.

[0020] R 1 When R is an alkyl group having 1 to 3 carbon atoms, the alkyl group may be linear or branched. A thermally detachable group is a group that is detached by heat to generate a hydrogen atom. 1 is a thermally detachable group, R 1Examples of the group include a carbamate structure-containing group, an amide structure-containing group, an imide structure-containing group, and a sulfonamide structure-containing group. Of these, a carbamate structure-containing group is preferred because of its high thermal elimination property. Specific examples include a tert-butoxycarbonyl group, a benzyloxycarbonyl group, a 1,1-dimethyl-2-haloethyloxycarbonyl group, an allyloxycarbonyl group, a 2-(trimethylsilyl)ethoxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, and an allyloxycarbonyl group. Of these, a tert-butoxycarbonyl group (Boc group) is particularly preferred because of its excellent thermal elimination property and its ability to reduce the amount of deprotected moieties remaining in the film.

[0021] R 1 is preferably a hydrogen atom, a methyl group or a thermally labile group, more preferably a hydrogen atom, in that a liquid crystal alignment film with high mechanical strength can be obtained.

[0022] Y 1 The divalent organic group represented by the formula (I) is a divalent hydrocarbon group having 1 to 20 carbon atoms; any methylene group in the hydrocarbon group is -O-, -S-, -CO-, -COO-, -OCO-, -NR-, -NR 10 CO-, -CONR 10 -, -NR 10 COO-, -OCONR 10 -, -NR 10 -CO-NR 11 - or the like (provided that R 10 and R 11 are each independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms or a thermally eliminable group (the same applies below); a group having a heterocyclic structure, and the like.

[0023] Y 1When is a divalent hydrocarbon group having 1 to 20 carbon atoms, examples of the hydrocarbon group include a chain hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, and an aromatic hydrocarbon group having 6 to 20 carbon atoms. Specific examples of these include divalent chain hydrocarbon groups having 1 to 20 carbon atoms, such as methylene, ethylene, 1,3-propanediyl, 1,2-propanediyl, 2,2-propanediyl, 1,4-butanediyl, 1,3-butanediyl, 1,2-butanediyl, 2,2-butanediyl, and pentanediyl groups; alkenediyl groups such as ethenediyl, 1,3-propenediyl, 1,4-butenediyl, and 1,5-pentenediyl groups; and alkynediyl groups such as ethynediyl, 1,3-propenediyl, 1,4-butynediyl, and 1,5-pentenediyl groups.

[0024] Examples of the divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic alicyclic saturated hydrocarbon groups such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl groups; polycyclic alicyclic saturated hydrocarbon groups such as norbornanediyl, adamantanediyl, tricyclodecanediyl, and tetracyclododecanediyl groups; monocyclic alicyclic unsaturated hydrocarbon groups such as cyclopropenediyl, cyclobutenediyl, cyclopentenediyl, and cyclohexenediyl groups; and polycyclic alicyclic saturated hydrocarbon groups such as norbornenediyl and tricyclodecenediyl groups. 1 The divalent alicyclic hydrocarbon group represented by the formula (I) may be a group in which a divalent aliphatic ring group such as a cyclopropanediyl group or a cyclopentanediyl group is bonded to the above-mentioned divalent chain hydrocarbon group.

[0025] Examples of the divalent aromatic hydrocarbon group having 6 to 20 carbon atoms include arylene groups such as a phenylene group, a tolylene group, a xylylene group, a naphthylene group, and an anthrylene group; 1 -Ar 4 -R 22 -or* 1 -R 22 -Ar 4 - (wherein Ar 4represents a substituted or unsubstituted phenylene group, R 22 is a divalent chain hydrocarbon group, * 1 " is X in formula (1) 1 (representing a bond with ).

[0026] In addition, X 1 If is a single bond, Y 1 is the carbon atom and Ar 1 Y 1 is a carbon atom and Ar 1 If it is bonded to Y 1 Specific examples of 1 Examples of the bond to Y include a saturated or unsaturated chain hydrocarbon group, a saturated or unsaturated alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a carbonyl group. 1 is a carbon atom and Ar 1 When Y is bonded to 1 Further examples of * 2 -CH2-R 23 -, * 2 -CH=CH-R 23 -, * 2 -C≡CR 23 -, * 2 -CO-R 23 -, * 2 -Ph 1 -R 23 -, * 2 -Cy 1 -R 23 -(Ph 1 is a substituted or unsubstituted phenylene group, and Cy 1 is a substituted or unsubstituted cycloalkylene group, and R 23 is a single bond or a divalent organic group, and "* 2 " is Ar 1 R 23 Specific examples of the divalent organic group represented by the formula (I) include divalent hydrocarbon groups having 1 to 18 carbon atoms; 10 CO-, -CONR 10 -, -NR 10 COO-, -OCONR 10 -, -NR10 -CO-NR 11 Examples of the group include a divalent group having 1 to 18 carbon atoms substituted with - or the like; and a group having a heterocyclic structure.

[0027] From the viewpoint of sufficiently reducing the residual charge accumulated in the liquid crystal element and increasing the transmittance of the liquid crystal element, Y 1 is a chain structure in part or in whole, and Ar 3 is preferably bonded to the nitrogen atom to which Y is bonded in a chain structure. 1 The bonding site with the nitrogen atom (i.e., Y 1 Ar 2 The chain structure at the end of the Y-type polymer may be saturated or unsaturated, and may be linear or branched. 1 Ar 3 is preferably bonded to the nitrogen atom to which it is bonded via a divalent linear hydrocarbon group, more preferably via a linear alkanediyl group.

[0028] In order to minimize the occurrence of afterimages and bright spots in liquid crystal elements, "-X 1 -Y 1 The group represented by "-" is X 1 is -O-, -S- or -NR 1 -Y 1 is a divalent organic group, or X 1 is a single bond and Y 1 is a chain structure in part or in whole, and Y 1 is a chain structure and Ar 1 Preferably, X is bonded to 1 When Y is a single bond, from the viewpoint of further enhancing the effect of reducing accumulated residual charges and the effect of improving transmittance, 1 Ar 1 is preferably bonded to via a divalent linear hydrocarbon group, more preferably via a linear alkanediyl group.

[0029] "-X 1 -Y 1Among the above, the group represented by "-" is Y 1 is preferably a divalent chain group. 1 represents a divalent chain hydrocarbon group having 1 to 20 carbon atoms, or any methylene group contained in the chain hydrocarbon group is -O-, -S-, -CO-, -COO-, -OCO-, -NR-, -NR 10 CO-, -CONR 10 -, -NR 10 COO-, -OCONR 10 -or-NR 10 -CO-NR 11 It is preferably a divalent group having 1 to 20 carbon atoms in which any methylene group in the alkanediyl group is replaced by -O-, -S-, -CO-, -COO-, -OCO-, -NR-, -NR 10 CO-, -CONR 10 -, -NR 10 COO-, -OCONR 10 -or-NR 10 -CO-NR 11 It is more preferable that R is a divalent group having 1 to 20 carbon atoms and substituted with -. 10 and R 11 has the same meaning as above.

[0030] Y 1 When Y is a divalent chain group, from the viewpoint of obtaining a liquid crystal alignment film having sufficiently high mechanical strength, 1 The number of carbon atoms in Y is preferably 10 or less, and more preferably 4 or less. 1 The number of carbon atoms in X is preferably 1 or more, and more preferably 2 or more. 1 is a single bond, and Y 1 When Y is a divalent chain group, from the viewpoint of the stability of the compound, 1 It is preferable that the number of carbon atoms is 2 or more.

[0031] X 1 Among the above, -O- or -S- is preferred, and -O- is more preferred, in that the transmittance of the resulting liquid crystal alignment film can be made sufficiently high.

[0032] Ar 2 , Ar 3 and Y 1 If satisfies the above requirement (ii), then Ar 2 and Ar 3 are combined together, and Ar 2 and Ar 3 Examples of the nitrogen-containing aromatic fused ring structure formed together with the nitrogen atom to which is bonded include a carbazole ring structure and an acridine ring structure. Of these, the nitrogen-containing aromatic fused ring structure is preferably a carbazole ring structure. In the nitrogen-containing aromatic fused ring structure, the nitrogen-containing aromatic fused ring may have a substituent. Examples of the substituent include a methyl group, an ethyl group, a hydroxyl group, and a halogen atom. Ar 1 a divalent aromatic ring group represented by X 1 a group represented by Y 1 Specific and preferred examples of the divalent organic group represented by Ar 2 , Ar 3 and Y 1 The same groups as those described in the case where requirement (i) is satisfied are exemplified.

[0033] Ar 2 , Ar 3 and Y 1 If satisfies the above requirement (iii), then Ar 3 and Y 1 are combined together, and Ar 3 and Y 1 In a divalent group containing a nitrogen-containing aromatic fused ring structure formed together with the nitrogen atom to which Ar is bonded (hereinafter also referred to as a "divalent group ArY"), specific examples and preferred examples of the nitrogen-containing aromatic fused ring structure are as follows: Ar 2 , Ar 3 and Y 1 The divalent group ArY is the same as the group described when the nitrogen-containing aromatic fused ring is X 1 or Ar 1 The nitrogen-containing fused aromatic ring may be directly bonded to X via a divalent linking group. 1 or Ar1 The divalent linking group preferably has a chain structure in part or in whole, more preferably a linear alkanediyl group, and even more preferably a linear alkanediyl group having 1 to 4 carbon atoms. Ar 1 or Ar 2 a divalent aromatic ring group represented by X 1 Specific and preferred examples of the group represented by Ar 2 , Ar 3 and Y 1 The same groups as those described in the case where requirement (i) is satisfied are exemplified.

[0034] Specific examples of the specific diamine include compounds represented by the following formulas (1-1) to (1-26). [ka] [ka] [ka]

[0035] In the polymer (P), the content of the structural units derived from the specific diamine is preferably 0.5 mol % or more, more preferably 5 mol % or more, and more preferably 10 mol % or more, based on all structural units derived from the monomers constituting the polymer (P). Also, the content of the structural units derived from the specific diamine is preferably 50 mol % or less, based on all structural units derived from the monomers constituting the polymer (P).

[0036] The polymer (P) may be any polymer containing a structural unit derived from a specific diamine, and the type of main skeleton thereof is not particularly limited. Examples of the polymer (P) include polyamic acid, polyamic acid ester, polyimide, polyamide, polyamideimide, polyurea, polyenamine, etc. In terms of being able to form a liquid crystal alignment film with high mechanical strength and obtain a highly reliable liquid crystal device, the polymer (P) is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. In other words, the polymer (P) is preferably a polymer containing a structural unit derived from a tetracarboxylic acid derivative and a structural unit derived from a diamine compound.

[0037] [Polyamic acid] When the polymer (P) is a polyamic acid, the polyamic acid (hereinafter also referred to as "polyamic acid (P)") can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound containing a specific diamine.

[0038] Tetracarboxylic acid dianhydride Examples of the tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid (P) include aliphatic tetracarboxylic acid dianhydrides and aromatic tetracarboxylic acid dianhydrides, etc. Examples of the aliphatic tetracarboxylic acid dianhydrides include linear tetracarboxylic acid dianhydrides and alicyclic tetracarboxylic acid dianhydrides.

[0039] Specific examples of these include chain tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride and ethylenediaminetetraacetic dianhydride. Examples of alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione ... 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, and the like.

[0040] Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol bisanhydrotrimate, 4,4'-carbonyldiphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenylethertetracarboxylic dianhydride, etc. In addition, when synthesizing the polyamic acid (P), the tetracarboxylic dianhydrides described in JP-A-2010-97188 can be used.

[0041] (diamine compounds) The diamine compound used in the synthesis of the polyamic acid (P) may be the specific diamine alone, or the specific diamine may be used in combination with a diamine different from the specific diamine (hereinafter also referred to as "other diamine"). Examples of other diamines include aliphatic diamines, aromatic diamines, and diaminoorganosiloxanes. Examples of aliphatic diamines include linear diamines and alicyclic diamines.

[0042] Specific examples of other diamines include chain diamines such as metaxylylenediamine and hexamethylenediamine, and alicyclic diamines such as 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine).

[0043] Aromatic diamines include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4-aminophenyl-4-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,5-bis(4-aminophenoxy)pentane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,6-bis(4-aminophenoxy)hexane, 6,6'-(pentamethylenedioxy)bis(3-aminopyridine), N,N'-di(5-amino-2-pyridyl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine, and bis[2-(4-aminophenyl)ethyl]heteroaryl. xanthane diacid, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenethyl urea, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-(phenylenediisopropylidene)bisaniline, 2,6-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 3,6-diaminoacridine, [ka] (In formula (D-1), R 11 and R 12 are each independently an alkanediyl group. 13 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally detachable group. n1 is an integer of 1 to 3. When n1 is 2 or 3, multiple R12 are the same or different, and multiple R 13 are the same or different.) Main chain diamines such as compounds represented by the following formula: Hexadecanoxy-2,4-diaminobenzene, Octadecanoxy-2,4-diaminobenzene, Octadecanoxy-2,5-diaminobenzene, Cholestanyloxy-3,5-diaminobenzene, Cholesteryloxy-3,5-diaminobenzene, Cholestanyloxy-2,4-diaminobenzene, Cholesteryloxy-2,4-diaminobenzene, Cholestanyloxy-3,5-diaminobenzoate, Cholesteryl 3,5-diaminobenzoate , lanostannyl 3,5-diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 3,5-diaminobenzoic acid = 5ξ-cholestan-3-yl, the following formula (E-1): [ka] (In formula (E-1), X I and X II are each independently a single bond, -O-, *-COO- or *-OCO- (where "*" represents X I It shows the bond with R. I is an alkanediyl group having 1 to 3 carbon atoms. II R is a single bond or an alkanediyl group having 1 to 3 carbon atoms. III is an alkyl group, alkoxy group, fluoroalkyl group, or fluoroalkoxy group having 1 to 20 carbon atoms. a is 0 or 1. b is an integer of 0 to 3. c is an integer of 0 to 2. d is 0 or 1, provided that 1≦a+b+c≦3. Examples of the diaminoorganosiloxane include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane and the like.

[0044] Examples of the compound represented by the formula (D-1) include compounds represented by the following formulas (D-1-1) to (D-1-3). Examples of the compound represented by the formula (E-1) include compounds represented by the following formulas (E-1-1) to (E-1-4). Examples of the other diamines include compounds represented by the following formulas (F-1) to (F-7). The other diamines can be used alone or in combination of two or more. In the formulas, "Boc" represents a tert-butoxycarbonyl group (the same applies hereinafter). [ka] [ka]

[0045] In synthesizing the polyamic acid (P), the amount of the specific diamine used is preferably 1 mol % or more, more preferably 5 mol % or more, even more preferably 10 mol % or more, and even more preferably 20 mol % or more, based on the total amount of diamine compounds used in synthesizing the polyamic acid (P). By using the specific diamine in the above range, it is possible to sufficiently obtain the effects of suppressing the occurrence of bright spots and reducing afterimages in liquid crystal devices.

[0046] Synthesis of polyamic acid The polyamic acid (P) can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound, optionally together with a molecular weight modifier.

[0047] In the synthesis reaction of polyamic acid (P), the ratio of tetracarboxylic dianhydride to diamine compound is preferably such that 0.2 to 2 equivalents of acid anhydride groups of the tetracarboxylic dianhydride are used per equivalent of amino groups of the diamine compound. Examples of molecular weight modifiers include acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The ratio of the molecular weight modifier used is preferably 20 parts by mass or less per 100 parts by mass of the total of the tetracarboxylic dianhydride and diamine compound used.

[0048] In the synthesis reaction of polyamic acid (P), the reaction temperature is preferably −20° C. to 150° C., and the reaction time is preferably 0.1 to 24 hours. Examples of organic solvents used in the reaction include aprotic polar solvents, phenolic solvents, alcoholic solvents, ketone solvents, ester solvents, ether solvents, halogenated hydrocarbons, and hydrocarbons. Among these, it is preferable to use one or more solvents selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenols as the reaction solvent, or to use a mixture of one or more of these solvents with other organic solvents (e.g., butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount of organic solvent used is preferably such that the total amount of tetracarboxylic dianhydride and diamine compound is 0.1 to 50% by mass based on the total amount of the reaction solution.

[0049] When a polymer solution in which the polyamic acid (P) is dissolved is obtained by the above polymerization, this polymer solution may be used as it is for preparing a liquid crystal aligning agent, or the polyamic acid (P) contained in the polymer solution may be isolated and then used for preparing a liquid crystal aligning agent.

[0050] [Polyamic acid ester] When the polymer (P) is a polyamic acid ester, the polyamic acid ester can be obtained, for example, by [I] a method of reacting a polyamic acid (P) with an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester with a diamine compound, or [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine compound. The polyamic acid ester may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist. The reaction solution in which the polyamic acid ester is dissolved may be used as is for preparing a liquid crystal aligning agent. Alternatively, the polyamic acid ester contained in the reaction solution may be isolated, and the isolated polyamic acid ester may be used for preparing a liquid crystal aligning agent.

[0051] [Polyimide] When the polymer (P) is a polyimide, the polyimide (hereinafter also referred to as "polyimide (P)") can be obtained, for example, by imidizing polyamic acid (P) through dehydration and cyclization. The polyimide (P) may be a fully imidized product in which all of the amic acid structures contained in its precursor polyamic acid (P) have been dehydrated and cyclized, or a partially imidized product in which only a portion of the amic acid structures have been dehydrated and cyclized, resulting in both amic acid structures and imide ring structures. The polyimide (P) preferably has an imidization rate of 20 to 99%, more preferably 30 to 90%. The imidization rate is the ratio, expressed as a percentage, of the number of imide ring structures to the total number of amic acid structures and imide ring structures in the polyimide. Here, some of the imide rings may be isoimide rings.

[0052] The dehydration ring closure of the polyamic acid (P) is preferably carried out by dissolving the polyamic acid (P) in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating as needed. In this method, the dehydrating agent may be, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride. The amount of the dehydrating agent used is preferably 0.01 to 20 moles per mole of the amic acid structure of the polyamic acid (P). The dehydration ring closure catalyst may be, for example, a tertiary amine such as pyridine, collidine, lutidine, or triethylamine. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used.

[0053] Examples of organic solvents used in the dehydration ring-closing reaction include the organic solvents exemplified as those used in the synthesis of polyamic acid (P). The reaction temperature in the dehydration ring-closing reaction is preferably 0 to 180°C. The reaction time is preferably 1.0 to 120 hours. The reaction solution containing polyimide (P) obtained by the dehydration ring-closing reaction of polyamic acid (P) may be used as is for preparing a liquid crystal aligning agent. Alternatively, the polyimide (P) may be isolated from the reaction solution and used for preparing a liquid crystal aligning agent. The polyimide (P) can also be obtained by dehydration ring-closing of a polyamic acid ester.

[0054] The solution viscosity of the polymer (P) is preferably 10 to 800 mPa·s when the polymer (P) is prepared into a 10% by mass solution, and more preferably 15 to 500 mPa·s. The solution viscosity (mPa·s) is a value measured at 25°C using an E-type rotational viscometer for a 10% by mass polymer solution prepared using a good solvent for the polymer (P) (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0055] The weight average molecular weight (Mw) of the polymer (P) measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1,000 to 500,000, and more preferably 2,000 to 300,000. The molecular weight distribution (Mw / Mn), which is the ratio of Mw to the number average molecular weight (Mn) measured by GPC in terms of polystyrene, is preferably 7 or less, and more preferably 5 or less.

[0056] The content of the polymer (P) in the liquid crystal aligning agent is preferably 20 mass% or more, more preferably 40 mass% or more, and even more preferably 60 mass% or more, based on the total amount of solids contained in the liquid crystal aligning agent (i.e., the total mass of components other than the solvent of the liquid crystal aligning agent).

[0057] To suppress image retention due to charge accumulation, it is desirable to reduce both the image retention observed immediately after the voltage application is removed (i.e., in the short term) (hereinafter also referred to as "short-term image retention") and the image retention observed long after the voltage application is removed (i.e., in the long term) (hereinafter also referred to as "long-term image retention"). However, according to the inventors' studies, there is a trade-off between short-term image retention and long-term image retention, and attempts to improve one tend to worsen the other. The same is true for long-term image retention and the transmittance of a liquid crystal element. For example, attempts to reduce long-term image retention tend to decrease the transmittance of a liquid crystal element. In contrast, according to the present disclosure, by forming a liquid crystal alignment film using the polymer (P), it is possible to achieve high transmittance while reducing both short-term image retention and long-term image retention. Furthermore, the diamine represented by the above formula (1) constituting the polymer (P) has an asymmetric structure on both sides of the reference axis when the reference axis is positioned in a direction intersecting the extension direction of the main chain. Therefore, it is considered that the polymer (P) containing the structural unit derived from the diamine represented by the above formula (1) has low crystallinity, and even if decomposition products are generated by heat or light, the decomposition products are unlikely to crystallize. As a result, it is considered that the liquid crystal aligning agent containing the polymer (P) can suppress the occurrence of bright spots.

[0058] <Other ingredients> The liquid crystal aligning agent may contain, in addition to the polymer (P), components different from the polymer (P) (hereinafter also referred to as "other components"), if necessary.

[0059] [Polymer (Q)] The liquid crystal aligning agent of the present disclosure may further contain a polymer (hereinafter also referred to as "polymer (Q)") that does not contain a structural unit derived from a specific diamine. The main skeleton of the polymer (Q) is not particularly limited. Examples of the polymer (Q) include polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamideimide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, and addition polymer (e.g., (meth)acrylic polymer, styrene polymer, maleimide polymer, styrene-maleimide copolymer). Of these, the polymer (Q) is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer.

[0060] When the polymer (Q) is contained in the liquid crystal aligning agent, the content of the polymer (Q) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, relative to 100 parts by mass of the total amount of the polymer (P) and the polymer (Q) contained in the liquid crystal aligning agent. The content of the polymer (Q) is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, relative to 100 parts by mass of the total amount of the polymer (P) and the polymer (Q) contained in the liquid crystal aligning agent.

[0061] 〔solvent〕 The liquid crystal aligning agent of the present disclosure is prepared as a liquid composition obtained by dispersing or dissolving the polymer (P) and other components used as needed, preferably in a suitable solvent.

[0062] As the solvent, an organic solvent is preferably used, specific examples of which include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, phenol, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, 1-hexanol, 2-hexanol, propane-1,2-diol, 3-methoxy-1-butanol, ethylene glycol monomethyl ether, methyl lactate, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, ethyl propionate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, and ethylene glycol-i-propyl ether. Examples of suitable solvents include ethylene glycol 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, propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentanone, cyclohexanone, etc. The solvent may be used alone or in combination of two or more.

[0063] In addition to the above, other components to be blended into the liquid crystal aligning agent include, for example, a crosslinking agent, an antioxidant, a metal chelate compound, a curing accelerator, a surfactant, a filler, a dispersant, a photosensitizer, etc. The blending ratio of the other components can be appropriately selected depending on each compound within a range that does not impair the effects of the present disclosure.

[0064] The solid content concentration in the liquid crystal aligning agent (the proportion of the total mass of the components other than the solvent in the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected taking into consideration viscosity, volatility, etc. The solid content concentration of the liquid crystal aligning agent is preferably in the range of 1 to 10 mass %. A solid content concentration of 1 mass % or more is preferable in that it ensures a sufficient thickness of the coating film and makes it possible to obtain a liquid crystal alignment film that exhibits better liquid crystal alignment properties. On the other hand, a solid content concentration of 10 mass % or less makes it possible to make the coating film have an appropriate thickness, making it easier to obtain a liquid crystal alignment film that exhibits good liquid crystal alignment properties, and also tends to make the viscosity of the liquid crystal aligning agent appropriate, resulting in good coatability.

[0065] <Liquid crystal alignment film and liquid crystal element> The liquid crystal alignment film of the present disclosure is manufactured using the liquid crystal alignment agent prepared as described above. Furthermore, the liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The liquid crystal driving method in the liquid crystal element is not particularly limited, and can be applied to various modes, such as TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS type, FFS type, OCB (Optically Compensated Bend) type, and PSA (Polymer Sustained Alignment) type. The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, different substrates are used depending on the desired operation mode. Steps 2 and 3 are common to all operation modes.

[0066] <Step 1: Formation of coating film> First, a liquid crystal alignment agent is applied to a substrate, and the coated surface is preferably heated to form a coating film on the substrate. Examples of substrates that can be used include transparent substrates made of glass, such as float glass or soda glass; or plastics, such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefin). Examples of transparent conductive films that can be provided on one side of the substrate include NESA films (registered trademarks of PPG, Inc., USA) made of tin oxide (SnO2) and ITO films made of indium oxide-tin oxide (In2O3-SnO2). When manufacturing TN, STN, or VA liquid crystal devices, two substrates with patterned transparent conductive films are used. On the other hand, when manufacturing IPS or FFS liquid crystal devices, a substrate with comb-patterned electrodes and an opposing substrate without electrodes are used.

[0067] The method for applying the liquid crystal aligning agent to the substrate is not particularly limited. The liquid crystal aligning agent can be applied to the substrate by, for example, a spin coating method, a printing method (for example, an offset printing method, a flexographic printing method, etc.), an inkjet method, a slit coating method, a bar coater method, an extrusion die method, a direct gravure coater method, a chamber doctor coater method, an offset gravure coater method, an impregnation coater method, an MB coater method, etc.

[0068] After the liquid crystal aligning agent is applied, preliminary heating (pre-baking) is preferably carried out for the purpose of preventing dripping of the applied liquid crystal aligning agent. The pre-baking temperature is preferably 30 to 200°C, and the pre-baking time is preferably 0.25 to 10 minutes. Thereafter, the solvent is completely removed, and if necessary, a baking (post-baking) step is carried out for the purpose of thermally imidizing the amic acid structure present in the polymer. The baking temperature (post-baking temperature) at this time is preferably 80 to 280°C, more preferably 80 to 250°C. The post-baking time is preferably 5 to 200 minutes. The thickness of the film formed is preferably 0.001 to 1 μm.

[0069] <Step 2: Alignment Treatment> When producing a TN-, STN-, IPS-, or FFS-type liquid crystal device, the coating film formed in step 1 above is subjected to a treatment (alignment treatment) to impart liquid crystal alignment ability. This imparts the ability to align liquid crystal molecules to the coating film, turning it into a liquid crystal alignment film. The alignment treatment is preferably a rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton, nylon, or the like, or a photoalignment treatment in which the coating film is irradiated with light to impart liquid crystal alignment ability. When producing a vertical alignment-type liquid crystal device, the coating film formed in step 1 above may be used as a liquid crystal alignment film as is, or the coating film may be subjected to an alignment treatment to further enhance the liquid crystal alignment ability. Liquid crystal alignment films suitable for vertical alignment-type liquid crystal devices can also be preferably used for PSA-type liquid crystal devices.

[0070] Light irradiation for photoalignment can be performed by irradiating the coating film after the post-bake step, irradiating the coating film after the pre-bake step but before the post-bake step, or irradiating the coating film while it is being heated in at least one of the pre-bake step and the post-bake step. The radiation to be irradiated to the coating film can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm. Preferably, ultraviolet light containing light with a wavelength of 200 to 400 nm is used. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When non-polarized radiation is used, the irradiation direction is an oblique direction.

[0071] Examples of light sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, excimer lasers, etc. The radiation dose is preferably 200 to 30,000 J / m 2 and more preferably 500 to 10,000 J / m 2After the light irradiation for imparting alignment ability, the substrate surface may be washed with, for example, water, an organic solvent (e.g., methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.) or a mixture thereof, or the substrate may be heated.

[0072] <Step 3: Construction of liquid crystal cell> Two substrates with liquid crystal alignment films formed thereon are prepared as described above, and a liquid crystal cell is produced by disposing a liquid crystal between the two substrates arranged opposite each other. Examples of methods for producing a liquid crystal cell include disposing two substrates with a gap between them so that the liquid crystal alignment films face each other, bonding the peripheries of the two substrates together with a sealant, injecting liquid crystal into the cell gap surrounded by the substrate surfaces and the sealant, and sealing the injection hole, and using the ODF method. Examples of sealants that can be used include epoxy resins containing a curing agent and aluminum oxide spheres as spacers. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred.

[0073] In the PSA mode, a polymerizable compound (e.g., a polyfunctional (meth)acrylate compound) is filled into the cell gap together with the liquid crystal, and after the liquid crystal cell is constructed, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates. In producing a PSA liquid crystal element, the proportion of the polymerizable compound used is, for example, 0.01 to 3 parts by mass, preferably 0.05 to 1 part by mass, per 100 parts by mass of the total liquid crystal.

[0074] When manufacturing a liquid crystal display device, a polarizing plate is subsequently attached to the outer surface of the liquid crystal cell. Examples of polarizing plates include a polarizing film called an "H film" made by stretching and aligning polyvinyl alcohol and absorbing iodine, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

[0075] The liquid crystal element of the present disclosure can be effectively applied to various applications, specifically, for example, various display devices such as clocks, portable game machines, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays, as well as light control devices, retardation films, and the like.

[0076] According to the present disclosure described above, the following means are provided. [Means 1] A liquid crystal aligning agent containing a polymer (P) having a structural unit derived from the compound represented by the above formula (1). [Means 2] X in the above formula (1) 1 is -O-, -S- or -NR 1 - or X 1 is a single bond and Y 1 is a chain structure in part or in whole, and Y 1 is a chain structure and Ar 1 The liquid crystal aligning agent according to [Means 1], wherein the liquid crystal aligning agent is bonded to [Means 3] Y in the above formula (1) 1 is a divalent organic group having one or more carbon atoms, and a part or all of the group has a chain structure, and Ar 3 is bonded to the nitrogen atom to which it is bonded in a chain structure, the liquid crystal aligning agent according to [Means 1] or [Means 2]. [Means 4] The liquid crystal aligning agent according to any one of [Means 1] to [Means 3], wherein the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. [Means 5] The liquid crystal aligning agent according to any one of [Means 1] to [Means 4], further comprising a polymer (Q) that does not have a structural unit derived from the compound represented by the above formula (1). [Means 6] The liquid crystal aligning agent according to [Means 5], wherein the polymer (Q) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer. [Means 7] A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of [Means 1] to [Means 6]. [Means 8] A liquid crystal element comprising the liquid crystal alignment film according to [Means 7]. [Example]

[0077] Hereinafter, the present invention will be described in more detail based on examples, but the present invention should not be construed as being limited by the following examples.

[0078] In the following examples, the imidization rate of polyimide in the polymer solution, and the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer were measured by the following methods. The required amounts of raw material compounds and polymers used in the following examples were secured by repeating synthesis on a synthesis scale shown in the following synthesis examples as necessary.

[0079] [Imidization rate of polyimide] The polyimide solution was poured into pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. After that, it was dissolved in deuterated dimethyl sulfoxide and measured at room temperature using tetramethylsilane as a standard substance. 1 H-NMR measurement was carried out. 1 The imidization rate [%] was calculated from the H-NMR spectrum using the following formula (I). Imidization rate [%] = (1 - (A 1 / (A 2 ×α)))×100 …(I) (In formula (I), A 1 is the peak area due to the proton of the NH group that appears at a chemical shift of around 10 ppm, and A 2 is the peak area due to other protons, and α is the ratio of the number of other protons to one proton of the NH group in the polymer precursor (polyamic acid).

[0080] [Weight average molecular weight (Mw) and number average molecular weight (Mn)] Mw and Mn are values ​​calculated as polystyrene measured by GPC under the following conditions. Column: TSKgel GRCXLII, manufactured by Tosoh Corporation Solvent: tetrahydrofuran Temperature: 40℃ Pressure: 68kgf / cm 2

[0081] The abbreviations for the compounds are as follows: In the following, the compound represented by formula (X) may be simply referred to as "compound (X)". (Tetracarboxylic acid dianhydride) [ka]

[0082] (diamine compounds) [ka] [ka] [ka] [ka]

[0083] [ka] [ka]

[0084] (Other monomers) [ka] [ka] [ka]

[0085] (additives) [ka]

[0086] <Polymer synthesis> 1. Synthesis of polyamic acid [Synthesis Example 1] 95 moles of compound (TA-3) and 5 moles of compound (TA-8) as tetracarboxylic dianhydrides, and 80 moles of compound (DA-1) and 20 moles of compound (DB-5) as diamine compounds were dissolved in N-methyl-2-pyrrolidone (NMP), and the reaction was carried out at room temperature for 6 hours to obtain a solution containing 15 mass% of polyamic acid (referred to as polymer (PI-1)).

[0087] [Synthesis Examples 2 to 10, 12 to 14, 16 to 18, 20, 21, 24, 26, 28 to 30, 32, 33, 35 to 38] The same procedure as in Synthesis Example 1 was carried out, except that the types and amounts of tetracarboxylic dianhydrides and diamine compounds used were changed as shown in Tables 1 and 2, to obtain solutions containing polyamic acids (polymers (PI-2) to (PI-10), (PI-12) to (PI-14), (PI-16) to (PI-18), (PI-20), (PI-21), (PI-24), (PI-26), (PI-28) to (PI-30), (PI-32), (PI-33), and (PI-35) to (PI-38)).

[0088] 2. Polyimide Synthesis [Synthesis Example 11] 80 moles of compound (DA-11) and 20 moles of compound (DB-12) as diamine compounds were dissolved in N-methyl-2-pyrrolidone (NMP), and 90 moles of compound (TA-1) and 10 moles of compound (TA-3) as tetracarboxylic dianhydrides were added. The mixture was allowed to react at 40°C for 24 hours to obtain a solution containing 20% ​​by mass of polyamic acid. Next, NMP was added to the obtained polymer solution to make a solution with a polyamic acid concentration of 10% by mass, and pyridine and acetic anhydride were added to carry out a dehydration ring-closing reaction for 4 hours at 90° C. After the dehydration ring-closing reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by mass of polyimide with an imidization rate of approximately 60% (referred to as polymer (PI-11)).

[0089] [Synthesis Examples 15, 19, 22, 23, 25, 27, 31, 34] Solutions containing polyimides (polymers (PI-15), (PI-19), (PI-22), (PI-23), (PI-25), (PI-27), (PI-31), and (PI-34)) were obtained by the same procedure as in Synthesis Example 11, except that the types and amounts of tetracarboxylic dianhydrides and diamine compounds used were changed as shown in Tables 1 and 2. The imidization ratios of each polymer are also shown in Table 1.

[0090] [Table 1]

[0091] [Table 2]

[0092] 3. Synthesis of polyorganosiloxane [Synthesis Example 39] A 1000 mL three-neck flask was charged with 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (the compound represented by formula (S-1) above), 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine, and mixed at room temperature. Next, 100 g of deionized water was added dropwise from the dropping funnel over 30 minutes, and the mixture was stirred under reflux while reacting at 80°C for 6 hours. After the reaction was completed, the organic layer was removed and washed with a 0.2% by weight aqueous solution of ammonium nitrate until the water after washing was neutral. The solvent and water were then distilled off under reduced pressure. An appropriate amount of methyl isobutyl ketone was added to obtain a 50% by weight solution of polymer (ESSQ-1), a polyorganosiloxane having epoxy groups. In a 500 mL three-neck flask, 3.10 g of compound (C-1) (20 mol% relative to the amount of epoxy groups in the polymer (ESSQ-1)), 3.24 g of compound (C-2) (10 mol% relative to the amount of epoxy groups in the polymer (ESSQ-1)), 1.00 g of tetrabutylammonium bromide, 20.0 g of a solution containing the polymer (ESSQ-1), and 290.0 g of methyl isobutyl ketone were added and stirred at 90 ° C. for 18 hours. After cooling to room temperature, the separation and washing operation with distilled water was repeated 10 times. The organic layer was then recovered, concentrated using a rotary evaporator, and diluted with NMP twice. The solids concentration was then adjusted to 10% by mass using NMP to obtain an NMP solution of polyorganosiloxane (referred to as polymer (PSQ-1)).

[0093] 4. Synthesis of styrene-maleimide copolymer [Synthesis Example 40] Under nitrogen, a 100 mL two-neck flask was charged with 5.00 g of compound (M-1), 1.05 g of compound (M-2), 4.80 g of compound (M-3), and 2.26 g of compound (M-4) as polymerization monomers, 0.39 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, 0.39 g of 2,4-diphenyl-4-methyl-1-pentene as a chain transfer agent, and 52.5 mL of N-methyl-2-pyrrolidone (NMP) as a solvent, and polymerized at 70 °C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and dried under vacuum at room temperature for 8 hours to obtain a styrene-maleimide copolymer (referred to as polymer (MI-1)). The weight-average molecular weight (Mw) measured by GPC (reduced to polystyrene equivalent) was 30,000, and the molecular weight distribution (Mw / Mn) was 2.

[0094] [Synthesis Example 41] Under nitrogen, a 100 mL two-neck flask was charged with 10 mol parts of compound (M-5), 10 mol parts of compound (M-6), 30 mol parts of compound (M-7), 10 mol parts of compound (M-8), 20 mol parts of compound (M-9), and 20 mol parts of compound (M-10) as polymerization monomers, 2 mol parts of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, and 50 mL of tetrahydrofuran as a solvent, and polymerized at 70 °C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and dried under vacuum at room temperature for 8 hours to obtain a styrene-maleimide copolymer (referred to as polymer (MI-2)). The weight-average molecular weight (Mw) measured by GPC (reduced to polystyrene equivalent) was 92,700, and the molecular weight distribution (Mw / Mn) was 4.78.

[0095] <Preparation and Evaluation of Liquid Crystal Alignment Agent> FFS type liquid crystal display element [Example 1] 1. Preparation of Liquid Crystal Alignment Agent To a solution containing the polymer (PI-23) obtained in Synthesis Example 23, a solution containing the polymer (PI-21) obtained in Synthesis Example 21 was added so that the solid content ratio was polymer (PI-23):polymer (PI-21) = 70:30 (mass ratio), and 3 parts by mass of additive (AD-2) was further added per 100 parts by mass of the total of polymer (PI-23) and polymer (PI-21). The solution was diluted with NMP and butyl cellosolve (BC) to obtain a solution with a solvent composition of NMP / BC = 80 / 20 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered through a 0.2 μm pore size filter to prepare a liquid crystal alignment agent (AL-1).

[0096] 2. Fabrication of FFS-mode liquid crystal cells using photoalignment method A glass substrate (referred to as the first substrate) with a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) laminated in this order on one side, and a glass substrate (referred to as the second substrate) without an electrode were prepared. Next, a liquid crystal alignment agent (AL-1) was applied to the electrode-forming surface of the first substrate and one side of the second substrate using a spinner, and heated (pre-baked) on a hot plate at 80°C for 1 minute. This was followed by drying (post-baking) for 30 minutes in an oven at 230°C with the interior replaced with nitrogen, forming a coating film with an average thickness of 0.1 μm. The resulting coating film was irradiated with 1,000 J / m of linearly polarized ultraviolet light containing a 254 nm emission line using an Hg-Xe lamp. 2 The coating film was then irradiated with light from the normal direction of the substrate to perform a photo-alignment treatment. The irradiation dose was measured using an actinometer measuring at a wavelength of 254 nm. The photo-aligned coating film was then heat-treated in a clean oven at 230°C for 30 minutes to form a liquid crystal alignment film. Next, for one of the pair of substrates on which the liquid crystal alignment film was formed, an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was applied by screen printing to the outer edge of the surface bearing the liquid crystal alignment film. The substrates were then stacked and pressed together so that the projection directions of the polarization axes on the substrate surfaces during light irradiation were antiparallel, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was filled between the pair of substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive to obtain an optical FFS-type liquid crystal cell. Furthermore, to remove the flow alignment that occurred during liquid crystal injection, the cell was heated at 120°C and then slowly cooled to room temperature. The above series of operations was also performed with a post-baking UV irradiation dose of 100 to 10,000 J / m. 2 Three or more liquid crystal cells with different amounts of ultraviolet light irradiation were manufactured by changing the exposure amount within the range of , and evaluation was performed using the liquid crystal cell with the exposure amount (optimum exposure amount) that showed the best alignment characteristics.

[0097] 3. Evaluation (1) Evaluation of charge accumulation characteristics (high-temperature short-term image retention) The liquid crystal cell manufactured in 2 above was placed in an environment of 60°C and 1 atmosphere. It was driven with an alternating current (AC) square wave of 30 Hz at a relative transmittance of 100% to set the luminance difference between any two pixels to 0, and then the luminance difference was measured at 5000 cd / m 2 Under backlight illumination, a direct current (DC) of 0.1 V was applied to only one pixel for 60 minutes while the device was driven with AC power and the relative transmittance was reduced to 50%. When the application of DC 0.1 V was stopped and the device was returned to AC-only operation, resulting in a 50% relative transmittance, a luminance difference ΔL occurred between the two pixels due to the accumulated charge. The smaller this luminance difference, the less likely charge was to accumulate at high temperatures, indicating better high-temperature short-term image retention. A luminance difference ΔL divided by the average luminance of the two pixels was evaluated as "very good (◎)" if it was less than 1%, "good (○)" if it was 1% or more but less than 2%, "fair (△)" if it was 2% or more but less than 3%, and "poor (×)" if it was 3% or more. As a result, this example was evaluated as "very good (◎)."

[0098] (2) Evaluation of image retention characteristics (long-term image retention) The liquid crystal cell manufactured in 2 above was placed in an environment of 25°C and 1 atmosphere. It was driven with an alternating current (AC) square wave of 30 Hz at a relative transmittance of 100% to set the luminance difference between any two pixels to 0, and then the luminance difference was measured at 5000 cd / m 2 Under backlight illumination, a direct current (DC) of 0.5V was applied to only one pixel for 60 minutes while the device was driven with AC power, allowing charge accumulation. When the application of DC 0.5V was terminated and the device was returned to AC-only operation, which resulted in a relative transmittance of 50%, a luminance difference ΔL occurred between the two pixels due to the accumulated charge. The time-dependent change in luminance difference ΔL was observed, and the time from the termination of application of DC 0.5V until the luminance difference ΔL fell to 36.8% or less of its initial value was defined as the image retention time. The shorter this time, the easier it was for the image retention caused by the accumulated charge to disappear, indicating good long-term room temperature image retention characteristics. The image retention time was evaluated as "very good (◎)" for a time less than 10 minutes, "good (○)" for a time between 10 and 20 minutes, "fair (△)" for a time between 20 and 30 minutes, and "poor (×)" for a time greater than 30 minutes. As a result, this example was rated "particularly good (◎)."

[0099] (3) Evaluation of bright spots The liquid crystal cell produced in 2 above was observed under a polarizing microscope (ECLIPSE E600WPOL) (Nikon Corporation) to evaluate the number of bright spots (emerging bright spots). Specifically, the liquid crystal cell was placed between two polarizing plates arranged so that the polarization axes were perpendicular, and the liquid crystal cell was observed under a polarizing microscope at 5x magnification (observation area: approximately 2500 μm × 2500 μm). The fewer the number of bright spots, the less highly crystalline pyrolysis products and photolysis products were generated, which is considered to be better. A number of bright spots less than 10 was rated as "excellent (◎)," 10 to 50 was rated as "good (○)," 50 to 100 was rated as "fair (△)," and 100 or more was rated as "poor (×)." As a result, in this example, the evaluation was "excellent (◎)."

[0100] (4) Evaluation of the mechanical properties of the membrane The liquid crystal alignment agent (AL-1) prepared in 1 above was applied to a glass substrate using a spinner and heated (pre-baked) on a hot plate at 110°C for 3 minutes. The substrate was then dried (post-baked) for 30 minutes in a nitrogen-purged oven at 230°C to form a coating film with an average thickness of 0.08 μm. The haze value of the coating film was measured using a haze meter. The coating film was then rubbed five times using a rubbing machine equipped with a roll wrapped around a cotton cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / sec, and a pile depth of 0.3 mm. The haze value of the liquid crystal alignment film was then measured using a haze meter, and the difference from the haze value before and after rubbing (haze change) was calculated. If the haze value of the film before rubbing is Hz1 (%) and the haze value of the film after rubbing is Hz2 (%), the haze change is expressed by the following formula (z-2): Haze change value (%) = Hz2 - Hz1 ... (z-2) When the haze change value of the liquid crystal alignment film was less than 0.5, it was evaluated as "excellent (◎)", when it was 0.5 or more but less than 0.8, it was evaluated as "good (○)", when it was 0.8 or more but less than 1.0, it was evaluated as "fair (△)", and when it was 1.0 or more, it was evaluated as "poor (×)". If the haze change value is less than 1.0, it can be said that the film strength is sufficiently high and the rubbing resistance is high, that is, the mechanical properties of the film are good. As a result, in this example, the film strength was evaluated as "excellent (◎)".

[0101] (5) Transmittance evaluation The liquid crystal alignment agent (AL-1) prepared in 1 above was applied to a quartz substrate using a spin coater. The substrate was then heated on a hot plate at 80°C for 1 minute, followed by 30 minutes in a nitrogen-purged oven at 230°C to form a coating with an average thickness of 100 nm. The absorption spectrum of the coated quartz substrate was measured in the UV-visible / NIR region using a UV-Vis / NIR spectrophotometer (JASCO Corporation, product name "V-670"), using an uncoated quartz substrate as a reference. Reflection was suppressed by using P-polarized light through a polarizing filter and setting the incident angle to the substrate at Brewster's angle. A transmittance of 98% or greater at a wavelength of 400 nm was evaluated as "excellent (◎)," 95% to less than 98% as "good (○)," 90% to less than 95% as "fair (△)," and less than 90% as "poor (×)." As a result, this example was rated as "excellent (◎)".

[0102] [Examples 2, 4, 5, 9, 10, 12 to 14, 16, 19, 21 and Comparative Examples 1, 2, 4, 6] A liquid crystal alignment agent was prepared in the same manner as in Example 1, except that the composition of the liquid crystal alignment agent was changed as shown in Table 3. In addition, using the obtained liquid crystal alignment agent, an optical FFS type liquid crystal cell was produced in the same manner as in Example 1, and various evaluations were performed. The results are shown in Table 3.

[0103] [Example 3] 1. Preparation of Liquid Crystal Alignment Agent NMP and butyl cellosolve (BC) were added to a solution containing the polymer (PI-28) obtained in Synthesis Example 28 to prepare a solution with a solvent composition of NMP / BC = 80 / 20 (mass ratio) and a solid content concentration of 3.5 mass %. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-3).

[0104] 2. Fabrication of FFS-type liquid crystal cells using the rubbing method A first substrate and a second substrate similar to those in Example 1 were prepared. Next, a liquid crystal alignment agent (AL-3) was applied to the electrode-forming surface of the first substrate and one side of the second substrate using a spinner, and heated (pre-baked) on a hot plate at 110°C for 3 minutes. This was followed by drying (post-baking) for 30 minutes in a nitrogen-purged oven at 230°C, forming a coating film with an average film thickness of 0.08 μm. Next, the coating film surface was subjected to a rubbing treatment using a rubbing machine equipped with a roll wrapped around a rayon cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / sec, and a pile indentation length of 0.3 mm. This was followed by ultrasonic cleaning in ultrapure water for 1 minute, followed by drying for 10 minutes in a clean oven at 100°C, yielding a pair of substrates with liquid crystal alignment films. Next, a pair of substrates with liquid crystal alignment films were screen-printed with an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres, leaving a liquid crystal injection port at the edge of the surface where the liquid crystal alignment film was formed. The substrates were then stacked and pressed together, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was injected into the gap between the pair of substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. To eliminate flow alignment during liquid crystal injection, the substrate was heated to 120°C and then slowly cooled to room temperature to produce a liquid crystal cell (rubbed FFS-type liquid crystal cell). When stacking the pair of substrates, the rubbing directions of each substrate were antiparallel.

[0105] 3. Evaluation Using the liquid crystal alignment agent prepared in 1 above and the liquid crystal cell produced in 2 above, various evaluations were carried out in the same manner as in Example 1. The evaluation results are shown in Table 3.

[0106] [Examples 6 to 8, 11, 15, 17, 18, and 20 and Comparative Examples 3, 5, 7, and 8] A liquid crystal alignment agent was prepared in the same manner as in Example 3, except that the composition of the liquid crystal alignment agent was changed as shown in Table 3. In addition, a rubbed FFS-type liquid crystal cell was produced using the obtained liquid crystal alignment agent in the same manner as in Example 3, and various evaluations were performed. The evaluation results are shown in Table 3.

[0107] [Table 3]

[0108] PSA type liquid crystal display element [Example 22] 1. Preparation of Liquid Crystal Alignment Agent To a solution containing the polymer (PI-32) obtained in Synthesis Example 32, 5 parts by mass of additive (AD-4) was added relative to 100 parts by mass of polymer (PI-32), and the mixture was diluted with NMP and BC to obtain a solution with a solvent composition of NMP / BC=50 / 50 (mass ratio) and a solids concentration of 3.5% by mass. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-30).

[0109] 2. Manufacturing of PSA type liquid crystal cells (1) Preparation of liquid crystal composition 5% by mass of a liquid crystal compound represented by the following formula (L1-1) and 0.3% by mass of a photopolymerizable compound represented by the following formula (L2-1) were added to 10 g of nematic liquid crystal (MLC-6608, manufactured by Merck) and mixed to obtain liquid crystal composition LC1. [ka]

[0110] (2) Liquid crystal cell manufacturing The liquid crystal alignment agent (AL-30) prepared above was applied to the transparent electrode surface of a glass substrate with an ITO transparent electrode using a spinner. The substrate was prebaked on a hot plate at 80°C for 1 minute, and then heated in a nitrogen-purged oven at 200°C for 1 hour to remove the solvent, forming a 0.08 μm-thick coating (liquid crystal alignment film). This coating film was then rubbed using a rubbing machine equipped with a roll wrapped around a rayon cloth at a roll rotation speed of 400 rpm, a stage movement speed of 3 cm / sec, and a pile depth of 0.1 mm. The substrate was then ultrasonically cleaned in ultrapure water for 1 minute and then dried in a clean oven at 100°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. This process was repeated to obtain a pair (two substrates) with a liquid crystal alignment film. Note that this rubbing treatment was weak, intended to suppress liquid crystal collapse and facilitate alignment division. An epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was applied by screen printing to the outer periphery of the surface of one of the substrates bearing the liquid crystal alignment film, and then the liquid crystal alignment film surfaces of the pair of substrates were placed facing each other, overlapped, and pressed together, followed by heating at 150°C for 1 hour to thermally cure the adhesive. Next, liquid crystal composition LC1 was filled into the gap between the substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. To prevent flow alignment during liquid crystal injection, the resulting mixture was heated at 150°C for 10 minutes and then slowly cooled to room temperature. Next, an AC voltage of 10 V at a frequency of 60 Hz was applied between the electrodes of the obtained liquid crystal cell, and while the liquid crystal was in a driving state, ultraviolet rays of 50,000 J / m were irradiated using an ultraviolet irradiation device that used a metal halide lamp as a light source. 2 The irradiation amount was measured using an actinometer measuring at a wavelength of 365 nm as a reference. A PSA liquid crystal cell was thus produced.

[0111] 3. Evaluation Using the liquid crystal alignment agent prepared in 1 above and the liquid crystal cell produced in 2 above, various evaluations were carried out in the same manner as in Example 1. The evaluation results are shown in Table 4.

[0112] [Examples 23 to 26 and Comparative Examples 9 to 12] A liquid crystal alignment agent was prepared in the same manner as in Example 22, except that the composition of the liquid crystal alignment agent was changed as shown in Table 4. In addition, a PSA type liquid crystal cell was produced using the obtained liquid crystal alignment agent in the same manner as in Example 22, and various evaluations were performed. The evaluation results are shown in Table 4.

[0113] [Table 4]

[0114] Optical vertical LCD display element [Example 27] 1. Preparation of Liquid Crystal Alignment Agent To a solution containing the polymer (PI-1) obtained in Synthesis Example 1, the polymer (MI-1) obtained in Synthesis Example 40 was added so that the polymer (MI-1) was 10 parts by mass relative to 90 parts by mass of the polymer (PI-1) in terms of solid content, and the mixture was diluted with NMP and BC to obtain a solution with a solvent composition of NMP / BC=80 / 20 (mass ratio) and a solid content concentration of 3.5% by mass. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-39).

[0115] 2. Fabrication of optical vertical liquid crystal cell (UV2A) The liquid crystal alignment agent (AL-39) prepared in 1 above was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a spinner, and pre-baked on a hot plate at 80°C for 1 minute. The coating was then heated at 230°C for 1 hour in an oven with the interior replaced with nitrogen, forming a coating film with a thickness of 0.1 μm. Next, the surface of this coating was irradiated with polarized ultraviolet light at 1,000 J / m², including a 313 nm emission line, using an Hg-Xe lamp and a Glan-Taylor prism. 2 The substrate was irradiated with light from a direction tilted by 40° from the normal to the substrate to impart liquid crystal alignment ability. The same procedure was repeated to prepare a pair (two substrates) having a liquid crystal alignment film. An epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was screen-printed onto the outer periphery of the surface of one of the substrates bearing the liquid crystal alignment film. The pair of substrates were then placed with the liquid crystal alignment film surfaces facing each other and pressed together so that the UV light axes of the substrates were antiparallel to each other. The adhesive was then thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was injected into the gap between the substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. To eliminate flow alignment during liquid crystal injection, the substrate was heated to 130°C and then slowly cooled to room temperature.

[0116] 3. Evaluation Using the liquid crystal alignment agent prepared in 1 above and the liquid crystal cell produced in 2 above, various evaluations were carried out in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0117] [Example 28 and Comparative Examples 13 and 14] A liquid crystal alignment agent was prepared in the same manner as in Example 27, except that the composition of the liquid crystal alignment agent was changed as shown in Table 5. In addition, a vertically lighted liquid crystal cell was produced using the obtained liquid crystal alignment agent in the same manner as in Example 27, and various evaluations were performed. The evaluation results are shown in Table 5.

[0118] [Table 5]

[0119] From the above results, it became clear that a liquid crystal alignment agent containing polymer (P) can form a liquid crystal alignment film with high mechanical strength, and can also produce liquid crystal elements that are less likely to produce afterimages or bright spots and have high transmittance.

Claims

1. A liquid crystal aligning agent comprising a polymer (P) having a structural unit derived from a compound represented by the following formula (1): 【Chemistry 1】 (In formula (1), Ar １ is a divalent aromatic ring group. １ represents a single bond, —O—, —S—, or —NR １ - is. R １ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally detachable group. ２ , Ar ３ and Y １ satisfies the following requirement (i), (ii), or (iii), provided that X １ When Y is a single bond, １ is a carbon atom and Ar １ is bonded to. (i) Ar ２ is a divalent aromatic ring group. ３ is a monovalent aromatic ring group. １ is a divalent organic group having one or more carbon atoms. (ii) Ar ２ and Ar ３ are combined together to form Ar ２ and Ar ３ represents a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which Y is bonded. １ is a divalent organic group having one or more carbon atoms. (iii) Ar ２ is a divalent aromatic ring group. ３ and Y １ are combined together to form Ar ３ and Y １ is a divalent group containing a nitrogen-containing aromatic fused ring structure formed together with the nitrogen atom to which

2. X in the above formula (1) １ is —O—, —S— or —NR １ - or X １ is a single bond and Y １ is a chain structure in part or in whole, and Y １ is a chain structure and Ar １ The liquid crystal aligning agent according to claim 1 , wherein the

3. Y in the above formula (1) １ is a divalent organic group having one or more carbon atoms, and a part or all of the group has a chain structure, and Ar ３ The liquid crystal aligning agent according to claim 1 , wherein the nitrogen atom is bonded to the nitrogen atom via a chain structure.

4. The liquid crystal aligning agent according to claim 1, wherein the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

5. The liquid crystal aligning agent according to claim 1, further comprising a polymer (Q) having no structural unit derived from the compound represented by formula (1).

6. The liquid crystal aligning agent according to claim 5, wherein the polymer (Q) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer.

7. A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of claims 1 to 6.

8. A liquid crystal device comprising the liquid crystal alignment film according to claim 7 .

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