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

Abstract

Provided is a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal element, which can obtain a liquid crystal element having good liquid crystal alignment properties and light resistance. The liquid crystal alignment agent contains a polymer (P) having a partial structure represented by formula (1), a compound (H) having a hindered amine structure, and a compound (Q) having two or more oxirane groups or the like in one molecule and not having an aromatic ring. In formula (1), X2 is a divalent group having a basic functional group.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal element. BACKGROUND

[0002] A liquid crystal element includes a liquid crystal alignment film having a function of controlling the alignment of liquid crystal molecules in a liquid crystal layer. As a material of the liquid crystal alignment film, a polyamic acid or a polyamic acid ester, a polyimide is generally used from the viewpoints of mechanical strength or affinity with a liquid crystal, voltage holding characteristics, and the like.

[0003] A liquid crystal element is widely utilized in televisions or mobile devices, various monitors, and the like. Along with such versatility, further high quality of the liquid crystal element is required, and along with the improvement of the driving method or the element structure, the improvement of the liquid crystal alignment film as one of the constituent materials of the liquid crystal element is promoted (for example, refer to Patent Literature 1).

[0004] It is disclosed in Patent Literature 1 that a liquid crystal alignment film is formed using a compound having a hindered amine structure, a compound having a hindered phenol structure, or a compound having a hindered amine structure and a hindered phenol structure. In Patent Literature 1, by allowing the hindered amine structure and the hindered phenol structure to exist in the liquid crystal alignment film, the residual image characteristics or the light resistance of the liquid crystal element, display unevenness around a sealant are improved.

[0005] [Patent Literature]

[0006] [Patent Literature]

[0007] [Patent Literature 1] Japanese Patent Application Laid-Open No. 2020-154185 SUMMARY

[0008] [Problem to be Solved by the Invention]

[0009] The present inventors and others have conducted research, and as a result, it has been clarified that, in a case where it is intended to improve the characteristics of a liquid crystal element using the radical capturing ability of a compound having a hindered amine structure, the performance of the compound having a hindered amine structure does not sufficiently appear in a liquid crystal alignment film containing a polymer having an amic acid structure, and the light resistance of the liquid crystal element is not sufficient. In addition, the liquid crystal alignment property, which is one of the basic characteristics, is also required to be good for the liquid crystal element.

[0010] The present application was made in view of the above-described circumstances, and the main object is to provide a liquid crystal alignment agent by which a liquid crystal element having good liquid crystal alignment property and light resistance can be obtained.

[0011] [Technical Means for Solving the Problem]

[0012] The present application employs the following means in order to solve the problem.

[0013] A liquid crystal alignment agent containing: a polymer (P) having a partial structure represented by the following formula (1); a compound (H) having a hindered amine structure; and a compound (Q) having at least one selected from the group consisting of an oxirane group, an oxetane group, a partial structure represented by the following formula (7), a partial structure represented by the following formula (8), and a partial structure represented by the following formula (9) in one molecule, and not having an aromatic ring.

[0014] [Chemical Formula 1]

[0015]

[0016] (In formula (1), X 1 is a tetravalent organic group; X 2 is a divalent group having at least one selected from the group consisting of a partial structure represented by the following formula (2), a partial structure represented by the following formula (3), a partial structure represented by the following formula (4), and a partial structure represented by the following formula (5)

[0017] [Chemical Formula 2]

[0018]

[0019] (In formulae (2) to (5), R 1a , R 1b , R 2a , R 2b , R 3a , R 3b , R 4a , and R 4b are each independently a hydrogen atom or a monovalent organic group; L 1 and L 2 are each independently a hydrogen atom, a thermally dissociable group, or a monovalent hydrocarbon group; L 3 is a hydrogen atom, a thermally dissociable group, or a monovalent aliphatic hydrocarbon group; Ar 1 is a divalent aromatic group; Ar 2 is a divalent group obtained by removing two hydrogen atoms from a ring portion of a nitrogen-containing heteroaromatic ring; and "*" represents a bond)

[0020] [Chemical Formula 3]

[0021]

[0022] (In formulae (7) to (9), R 14a , R 14b , R 15a , R 15b , R 16a , R 16b , R 17a , and R17b Each can be independently a hydrogen atom or a monovalent organic group; L 4 ~L 6 Each is independently a hydrogen atom or a thermally depleted radical; wherein, R 14a R 14b R 15a R 15b R 16a R 16b R 17a R 17b and L 4 ~L 6 (Does not have an aromatic ring; "*" indicates a bond)

[0023] <2> A liquid crystal alignment film is formed using the liquid crystal alignment agent described in <1>.

[0024] <3> A liquid crystal element comprising the liquid crystal alignment film of <2>.

[0025] [The effects of the invention]

[0026] According to the liquid crystal alignment agent of the present invention, a liquid crystal element exhibiting good liquid crystal alignment and good light resistance can be obtained. Detailed Implementation

[0027] The following provides a detailed explanation of matters related to the form of this disclosure. Furthermore, in this specification, the term "hydrocarbon group" encompasses chain-like hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Chain-like hydrocarbon group" refers to a straight-chain hydrocarbon group or branched hydrocarbon group that does not contain a cyclic structure but is composed solely of a chain structure. It can be saturated or unsaturated. "Alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as its ring structure and does not contain an aromatic ring structure. It is not necessary for it to be composed solely of an alicyclic hydrocarbon structure; it may also include groups with a chain structure in a portion thereof. "Aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as its ring structure. It is not necessary for it to be composed solely of an aromatic ring structure; it may also include a chain structure or an alicyclic hydrocarbon structure in a portion thereof.

[0028] The term "aliphatic hydrocarbon group" encompasses both chain-like and alicyclic hydrocarbon groups. The "main chain" of a polymer refers to the longest segment of its atomic chain. The "side chain" of a polymer refers to the portion that branches off from the main chain. An "organic group" is an atomic group formed by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound).

[0029] Liquid crystal alignment agent

[0030] The liquid crystal alignment agent of the present disclosure (hereinafter, also referred to as "the present alignment agent") contains a polymer (P), a compound (H), and a compound (Q) shown below.

[0031] Polymer (P): Polymer having a partial structure containing a basic functional group.

[0032] Compound (H): Compound having a hindered amine structure.

[0033] Compound (Q): Compound having two or more partial structures (or functional groups) that can react with a carboxyl group in one molecule, and not having an aromatic ring.

[0034] Hereinafter, each component is described in detail.

[0035] < Polymer (P) >

[0036] The polymer (P) is at least one selected from the group consisting of a polyamic acid, a polyamic acid ester, and a polyimide, and has a partial structure represented by the following formula (1).

[0037] [Chemical Formula 4]

[0038]

[0039] (In formula (1), X 1 is a tetravalent organic group; X 2 is a divalent group having at least one selected from the group consisting of a partial structure represented by the following formula (2), a partial structure represented by the following formula (3), a partial structure represented by the following formula (4), and a partial structure represented by the following formula (5)

[0040] [Chemical Formula 5]

[0041]

[0042] (In formulae (2) to (5), R 1a , R 1b , R 2a , R 2b , R 3a , R 3b , R 4a , and R 4b are each independently a hydrogen atom or a monovalent organic group; L 1 and L 2 are each independently a hydrogen atom, a thermally dissociable group, or a monovalent hydrocarbon group; L 3 is a hydrogen atom, a thermally dissociable group, or a monovalent aliphatic hydrocarbon group; Ar 1 is a divalent aromatic group; Ar 2A bivalent group formed by removing two hydrogen atoms from the ring portion of a nitrogen-containing heteroaromatic ring; "*" represents a bond

[0043] In the formula (1), X 1 is a tetravalent organic group derived from a tetracarboxylic acid derivative. Further, in the present specification, the "tetracarboxylic acid derivative" means a tetracarboxylic dianhydride, a tetracarboxylic acid diester, and a tetracarboxylic acid diester dihalide.

[0044] As the tetracarboxylic acid derivative constituting X 1 , a compound known as a tetracarboxylic acid derivative usable in the production of a polyamic acid, a polyamic acid ester, and a polyimide can be used. From the viewpoint of the solubility of the polymer (P) and the transparency of the liquid crystal alignment film, X 1 is preferably a substituted or unsubstituted tetravalent aliphatic hydrocarbon group. For example, the following tetravalent groups represented by the following formulas (9) to (14) can be exemplified.

[0045] [Chemical Formula 6]

[0046]

[0047] (In the formulas (9) to (14), R 20 and R 21 are each independently an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a halogenated alkoxy group having 1 to 6 carbon atoms, or a halogen atom; "*" represents a bond)

[0048] Among these, X 1 is preferably a substituted or unsubstituted tetravalent alicyclic hydrocarbon group. In the case where the liquid crystal alignment film is formed by a photo-alignment method, X 1 is preferably a tetravalent group having a cyclobutane ring structure. Specifically, the tetravalent group represented by the formula (9) or the formula (10) is preferable, and the tetravalent group represented by the formula (10) is particularly preferable. In the case where X 1 is the group represented by the formula (10), R 20 and R 21 are each independently an alkyl group having 1 to 3 carbon atoms, a halogenated alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a halogenated alkoxy group having 1 to 3 carbon atoms, or a halogen atom, and are particularly preferably a methyl group.

[0049] In the formula (1), X 2It is a divalent organic group derived from a diamine compound, and has at least one selected from the group consisting of the partial structure represented by formula (2), the partial structure represented by formula (3), the partial structure represented by formula (4), and the partial structure represented by formula (5) (hereinafter also referred to as "partial structure (X)"). From the viewpoint of suppressing light-induced degradation of the liquid crystal alignment film and fully obtaining the effect of improving the light resistance of the liquid crystal element, the polymer (P) is preferably having at least one selected from the group consisting of the partial structure represented by formula (3), the partial structure represented by formula (4), and the partial structure represented by formula (5), and more preferably having one or more of these in the main chain of the polymer.

[0050] In equations (2) to (5), in R 1a R 1b R 2a R 2b R 3a R 3b R 4a and R 4b (Hereinafter, sometimes represented as "R") 1a ~R 4b When R is a monovalent organic group, 1a ~R 4b Preferably, it is a monovalent hydrocarbon group with 1 to 10 carbon atoms, specifically including: monovalent chain hydrocarbon groups with 1 to 10 carbon atoms, monovalent alicyclic hydrocarbon groups with 3 to 10 carbon atoms, and monovalent aromatic hydrocarbon groups with 6 to 10 carbon atoms.

[0051] In terms of further improving the voltage retention rate of liquid crystal elements and making it difficult to hinder the liquid crystal alignment of liquid crystal elements, R 1a ~R 4b Preferably, it is a hydrogen atom or a monovalent aliphatic hydrocarbon group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and particularly preferably a hydrogen atom or a methyl group.

[0052] L 1 ~L 3 In this context, a thermally desorbable group is a group that substitutes for a hydrogen atom in an amino group; it refers to a group that is desorbed and substituted for a hydrogen atom through thermal assignment. In L... 1 ~L 3 In the case of a thermally detachable group, the thermally detachable group is formed during the process of coating a substrate with a liquid crystal alignment agent and heating it to form a liquid crystal alignment film. 1 ~L 3 This simplifies the process, and from this perspective, a group that decomposes at a temperature of 120°C to 300°C and undergoes substitution at the hydrogen atom is preferred. Specifically, L 1 ~L 3The heat detachable group of the amino group is preferably a tert-butyloxy carbonyl group (Boc group) or a 9-fluorenylmethyloxy carbonyl group, and particularly preferably a tert-butyloxy carbonyl group.

[0053] In L 1 and L 2 In the case where L is a monovalent hydrocarbon group, the hydrocarbon group is preferably a monovalent aliphatic hydrocarbon group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms, and further preferably an alkyl group having 1 to 3 carbon atoms. In the case where L 3 is an aliphatic hydrocarbon group, the aliphatic hydrocarbon group is preferably an alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms, and further preferably an alkyl group having 1 to 3 carbon atoms.

[0054] In view of further improving the light resistance of the liquid crystal element and the liquid crystal alignment property of the liquid crystal element (more specifically, the phase separation property in the blending of the non-photosensitive polymer), with respect to L 1 to L 3 wherein X is preferably a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 8 carbon atoms, or a tert-butyloxy carbonyl group, more preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a tert-butyloxy carbonyl group, and particularly preferably a tert-butyloxy carbonyl group.

[0055] As the divalent aromatic group of Ar 1 , a group obtained by removing two hydrogen atoms from a ring portion of an aromatic hydrocarbon ring or a heteroaromatic ring can be exemplified. As the aromatic hydrocarbon ring at this time, a benzene ring, a naphthalene ring, an anthracene ring, and the like can be exemplified. The heteroaromatic ring is preferably a nitrogen-containing heteroaromatic ring, and for example, a pyridine ring, a pyridazine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, a benzimidazole ring, and the like can be exemplified. These aromatic rings can have a substituent. As the substituent, for example, a halogen atom, an alkyl group, an alkoxy group, and the like can be exemplified. Furthermore, in the case where Ar 1 is a nitrogen-containing heteroaromatic ring, X 2 is a group having a partial structure represented by the formula (4), and also a group having a partial structure represented by the formula (5).

[0056] As the nitrogen-containing heteroaromatic ring constituting Ar 2 , for example, a pyrrole ring, an imidazole ring, a pyrazole ring, a triazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, an indole ring, a benzimidazole ring, a purine ring, a quinoline ring, an isoquinoline ring, a naphthylidine ring, a quinoxaline ring, a phthalazine ring, a triazine ring, and the like can be exemplified. In the nitrogen-containing heteroaromatic ring constituting Ar 2 , a substituent can be introduced to a carbon atom constituting the exemplified ring. As the substituent, for example, a halogen atom, an alkyl group, an alkoxy group, and the like can be exemplified. Among these, from the aspects of easiness of introduction into a polymer and improvement effect on the light resistance of the liquid crystal element, a pyridine ring, a pyridazine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, and a benzimidazole ring are preferable, and a pyridine ring, an imidazole ring, and a benzimidazole ring are more preferable.

[0057] <Synthesis of the polymer (P)>

[0058] The method for synthesizing the polymer (P) is not particularly limited, and can be obtained by appropriately combining conventional methods of organic chemistry. In the case where the polymer (P) is a polyamic acid, as for the polyamic acid (hereinafter, also referred to as "polyamic acid (P)"), for example, it can be obtained by a method of reacting a tetracarboxylic dianhydride with a diamine compound containing a diamine having the partial structure (X) (hereinafter, also referred to as "specific diamine").

[0059] • polyamic acid

[0060] (tetracarboxylic dianhydride)

[0061] As the tetracarboxylic dianhydride used in the synthesis of the polyamic acid (P), for example, aliphatic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides, etc. can be exemplified. As the aliphatic tetracarboxylic dianhydride, chain tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides can be exemplified.

[0062] As specific examples of these, the chain tetracarboxylic dianhydride can be exemplified by 1,2,3,4-butanetetracarboxylic dianhydride, ethylenediaminetetraacetic dianhydride, etc.

[0063] The alicyclic tetracarboxylic dianhydride can be exemplified by 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexen-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethyl-norbornane-2:3,5:6-dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclohexanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, etc.

[0064] The aromatic tetracarboxylic dianhydride can be exemplified by pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, p-phenylene bis(trimellitic acid monoester anhydride), ethylene glycol bis(trimellitic anhydride ester), 1,3-propanediol bis(trimellitic anhydride ester), 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-biphenyldicarboxylic dianhydride, etc., and in addition, the tetracarboxylic dianhydride described in Japanese Patent Laid-Open No. 2010-97188 can be exemplified.

[0065] In terms of improving the solubility of the polyamic acid (P) and obtaining a liquid crystal alignment film with high transparency, the tetracarboxylic dianhydride used in the synthesis of the polyamic acid (P) is preferably one that contains an aliphatic tetracarboxylic dianhydride, and more preferably one that contains an alicyclic tetracarboxylic dianhydride. In the case where an aliphatic tetracarboxylic dianhydride is used in the synthesis of the polyamic acid (P), the proportion of the aliphatic tetracarboxylic dianhydride is preferably 30 mol% or more, more preferably 50 mol% or more, and even more preferably 70 mol% or more, relative to the total amount of the tetracarboxylic dianhydride used in the synthesis of the polyamic acid (P). In the synthesis of the polyamic acid (P), one kind of tetracarboxylic dianhydride can be used alone, or two or more kinds of tetracarboxylic dianhydrides can be used in combination.

[0066] (diamine compound)

[0067] The specific diamine has no particular limitation as long as it has the partial structure (X). In terms of further improving the effect of improving the light resistance of the liquid crystal element, the partial structure (X) possessed by the specific diamine is preferably at least one selected from the group consisting of the partial structure represented by the formula (3), the partial structure represented by the formula (4), and the partial structure represented by the formula (5). Among them, in particular, the specific diamine is preferably a compound having at least one selected from the group consisting of the partial structure represented by the formula (3), the partial structure represented by the formula (4), and the partial structure represented by the formula (5) in the main chain.

[0068] As specific examples of the specific diamine, for example, compounds represented by the following formulae (d-1) to (d-24), and the like can be given. Furthermore, as the specific diamine, one kind can be used alone or two or more kinds can be used in combination.

[0069] [Chemical Formula 7]

[0070]

[0071] [Chemical Formula 8]

[0072]

[0073] (In the formula (d-12), t is an integer of 1 to 20)

[0074] [Chemical Formula 9]

[0075]

[0076] In the synthesis of the polyamic acid (P), the specific diamine can be used alone as the diamine compound, or a diamine compound (hereinafter, also referred to as "other diamine") different from the specific diamine can be used together with the specific diamine.

[0077] As other diamines, if diamine compounds having no partial structure (X), there is no particular limitation, and for example, aliphatic diamines, aromatic diamines, and diaminosiloxanes, etc. can be exemplified. As aliphatic diamines, chain diamines and alicyclic diamines can be exemplified.

[0078] As specific examples of these, chain diamines can be exemplified by m-xylylenediamine, ethylenediamine, 1,3-propanediamine, tetramethylenediamine, hexamethylenediamine, etc.

[0079] Alicyclic diamines can be exemplified by p-cyclohexanediamine, 4,4'-methylenebis(cyclohexylamine), etc.

[0080] Aromatic diamines can be exemplified by dodecyloxydiaminobenzene, hexadecyloxydiaminobenzene, octadecyloxydiaminobenzene, cholestanyloxydiaminobenzene, cholestanolyloxydiaminobenzene, cholestanyl oxyl diamino benzoate, cholestanolyl oxyl diamino benzoate, lanostanyl oxyl diamino benzoate, 3,6-bis(4-aminobenzoyloxy)cholestan, 3,6-bis(4-aminophenoxy)cholestan, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 2,5-diamino-N,N-diallylaniline, a compound represented by the following formula (E-1), etc.

[0081] [Chemical Formula 10]

[0082]

[0083] (In formula (E-1), X I and X II are each independently a single bond, -O-, -COO-, or -OCO- (in which, “*” indicates a bonding bond with the diaminophenyl side); R I is an alkanediyl group having 1 to 3 carbons; R II is a single bond or an alkanediyl group having 1 to 3 carbons; R III is an alkyl group, an alkoxy group, a fluoroalkyl group, or a fluoroalkoxy group having 1 to 20 carbons; 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; and wherein, 1 ≦ a + b + c ≦ 3)

[0084] para-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-ethylenediaminodiphenylamine, 4,4'-diaminodiphenylether, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl sulfide, 4-aminophenyl-4'-aminobenzoate, O,O'-bis(4-aminophenyl)-glycol, N1,N6-bis(4-aminophhenyl)-N1,N6-di(tert-butoxycarbonyl)adipoyldiamine, N4,N4'-bis(4-aminophenyl)-N4,N4'-dimethylbenzidine, 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, 1,4-bis(4-aminophenoxy)piperazine, N,N'-bis(4-aminophenyl)-benzidine, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-(phenylenediisopropylidene)bisbenzenamine, 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 non-side chain type diamines;

[0085] Diaminoorganosiloxanes, for example, can include 1,3-bis(3-aminopropyl)- tetramethyldisiloxane and the like. In addition, the diamine compounds described in Japanese Patent Application Publication No. 2010-97188 can be used. Furthermore, one type of diamine or two or more types of diamines can be used alone or in combination as other diamines in the synthesis of the polyamic acid (P).

[0086] From the viewpoint of sufficiently obtaining the improvement effect on the light resistance of the liquid crystal element (particularly, the voltage holding property after applying a light stress to the liquid crystal alignment film or the liquid crystal cell), the use ratio of the specific diamine to the total amount of the diamine compounds used in the synthesis of the polyamic acid (P) is preferably 2 mol% or more, more preferably 5 mol% or more, further preferably 10 mol% or more, and still further preferably 15 mol% or more. In the case where other diamines are used together with the specific diamine, the use ratio of the specific diamine to the total amount of the diamine compounds used in the synthesis of the polyamic acid (P) is, for example, 80 mol% or less.

[0087] (Synthesis of the polyamic acid)

[0088] The polyamic acid (P) can be obtained by reacting a tetracarboxylic dianhydride as described above with a diamine compound and, if necessary, a molecular weight adjusting agent. As the molecular weight adjusting agent, for example, an acid mononahydride, a monoamine compound, a monoisocyanate compound, and the like can be exemplified. The use ratio of the tetracarboxylic dianhydride to the diamine compound for the synthesis reaction of the polyamic acid (P) is preferably 0.2 mole equivalent to 2 mole equivalent of the acid anhydride group of the tetracarboxylic dianhydride to 1 mole equivalent of the amino group of the diamine compound.

[0089] The synthesis reaction of the polyamic acid (P) is preferably performed in an organic solvent. The reaction temperature at this time is preferably -20°C to 150°C, and the reaction time is preferably 0.1 hour to 24 hours. As the organic solvent used in the reaction, for example, aprotic polar solvents, phenol-based solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like can be exemplified. A particularly preferable organic solvent is to use one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethyl urea, hexamethylphosphoric triamide, m-cresol, dimethylphenol, and halogenated phenol as the solvent, or a mixture of one or more of these and other organic solvents (for example, butyl cellosolve, diethylene glycol diethyl ether, diacetone alcohol, and the like). The amount of the organic solvent used is preferably set to an amount in which the total amount of the tetracarboxylic dianhydride and the diamine compound becomes 0.1 mass% to 50 mass% with respect to the total amount of the reaction solution. The reaction solution in which the polyamic acid (P) is dissolved can be directly used for the production of the liquid crystal alignment agent, or the polyamic acid (P) contained in the reaction solution can be separated and then used for the production of the liquid crystal alignment agent.

[0090] According to the alignment agent, in the case where a polymer having a photoalignment site is used as the polymer (P), deterioration of the liquid crystal alignment film caused by photo stress can also be suppressed, a liquid crystal element with improved light resistance can be produced, and it is thus suitable in this respect. Here, the so-called photoalignment site is a functional group that imparts anisotropy to a film through a photoisomerization reaction, a photodimerization reaction, a photodecomposition reaction, or a photorearrangement reaction, or the like based on light irradiation. As specific examples of the photoalignment site, mention can be made of 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 cyclobutane structure-containing group including cyclobutane or a derivative thereof 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 benzoic acid phenyl ester-containing group including benzoic acid phenyl ester or a derivative thereof as a basic skeleton, a coumarin-containing group including coumarin or a derivative thereof as a basic skeleton, and the like. Among these, the photoalignment site possessed by the polymer (P) is preferably a cyclobutane structure-containing group including a cyclobutane ring structure as a basic skeleton, more preferably a group represented by the formula (9) or formula (10), and further preferably a group represented by the formula (10). Among these, the photoalignment site possessed by the polymer (P) is particularly preferably a group having a structural unit derived from 1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride, in terms of high light sensitivity and the ability to provide a liquid crystal alignment property and voltage holding property that are excellent.

[0091] In the case where the polymer (P) is a polymer having a photoalignment site, the proportion of the structural unit derived from a monomer having a photoalignment site in the polymer (P) is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 15 mol% or more, relative to the total amount of the structural units derived from the monomers constituting the polymer (P). In the case where a tetracarboxylic acid derivative is used as a monomer that provides a photoalignment site to the polymer (P), the proportion of the structural unit derived from a monomer having a photoalignment site in the polymer (P) is generally 50 mol% or less, relative to the total amount of the structural units derived from the monomers constituting the polymer (P).

[0092] • Polyamide acid ester

[0093] In the case where the polymer (P) is a polyamic acid ester, the polyamic acid ester can be obtained, for example, by a method in which the obtained polyamic acid (P) is reacted with an esterification agent (for example, methanol or ethanol, N,N-dimethylformamide diethyl acetal, or the like), a method in which a tetracarboxylic acid diester is reacted with a diamine compound containing a specific diamine, preferably in an organic solvent and in the presence of a suitable dehydration catalyst (for example, 4-(4,6-dimethoxy-l,3,5-triazin-2-yl)-4-methylmorpholinium halide, carbonylimidazole, a phosphorus-based condensing agent, or the like), or a method in which a tetracarboxylic acid diester dihalide is reacted with a diamine compound containing a specific diamine, preferably in an organic solvent and in the presence of a suitable base (for example, pyridine, a tertiary amine such as triethylamine, or an alkali metal such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium, potassium, or the like).

[0094] The tetracarboxylic acid diester used in the [II] can be obtained by ring-opening a tetracarboxylic dianhydride using an alcohol or the like. The tetracarboxylic acid diester dihalide used in the [III] can be obtained by reacting a tetracarboxylic acid diester obtained as described above with a suitable chlorinating agent such as thionyl chloride.

[0095] The polyamic acid ester can have only a polyamic acid ester structure, or can be a partial ester in which a polyamic acid structure and a polyamic acid ester structure coexist. Further, in the case where the polyamic acid ester is obtained in the form of a solution by the reaction, the solution can be directly used for the production of the liquid crystal alignment agent, or the polyamic acid ester contained in the reaction solution can be separated and then used for the production of the liquid crystal alignment agent.

[0096] • a polyimide

[0097] In the case where the polymer (P) is a polyimide, the polyimide can be obtained, for example, by dehydrating and ring-closing and imidizing a polyamic acid (P) synthesized as described above. The polyimide can be a complete imidization product in which the polyamic acid structure possessed by the polyamic acid (P) as a precursor thereof is entirely dehydrated and ring-closed, or can be a partial imidization product in which only a part of the polyamic acid structure is dehydrated and ring-closed so that a polyamic acid structure and an imide ring structure coexist. The imidization rate of the polyimide is preferably 90% or less, more preferably 30% to 90%, and still more preferably 40% to 85%. The imidization rate is a percentage indicating the proportion of the number of imide ring structures with respect to the total of the number of polyamic acid structures and the number of imide ring structures. Further, a part of the imide ring can be an isoimide ring.

[0098] The dehydration ring closure of the polyamic acid (P) is preferably performed by a method in which the polyamic acid (P) is dissolved in an organic solvent, a dehydrating agent and a dehydration ring closure catalyst are added to the solution, and heating is performed as necessary. As the dehydrating agent, acid anhydrides such as acetic anhydride, propionic anhydride, trifluoroacetic anhydride, and the like can be used. The amount of the dehydrating agent used is preferably 0.01 to 20 moles per 1 mole of the amic acid structure of the polyamic acid (P). As the dehydration ring closure catalyst, tertiary amines such as pyridine, collidine, lutidine, triethylamine, and the like can be used.

[0099] The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per 1 mole of the dehydrating agent used. As the organic solvent used, the organic solvents exemplified as the organic solvents used in the synthesis of the polyamic acid (P) can be listed. The reaction temperature of the dehydration ring closure reaction is preferably 0°C to 180°C, and the reaction time is preferably 1.0 to 120 hours. The polyimide-containing reaction solution thus obtained can be directly used for the production of the liquid crystal alignment agent, or the polyimide can be isolated and then used for the production of the liquid crystal alignment agent.

[0100] When a solution having a concentration of 10 mass% is prepared, the solution viscosity of the polymer (P) is preferably 10 to 800 mPa-s, and more preferably 15 to 500 mPa-s. Further, the solution viscosity (mPa-s) is a value measured at 25°C using an E-type rotational viscometer for a polymer solution having a concentration of 10 mass% prepared using a good solvent for the polymer (P) (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, and the like).

[0101] The weight average molecular weight (Mw) of the polymer (P) measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1,000 to 500,000, and more preferably 5,000 to 100,000. The molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the number average molecular weight (Mn) measured by GPC in terms of polystyrene is preferably 15 or less, and more preferably 10 or less. Further, the polymer (P) contained in the liquid crystal alignment agent can be only one, or two or more can be combined.

[0102] <Compound (H)>

[0103] The compound (H) is a compound having a hindered amine structure, and specifically, a compound having a partial structure represented by the following formula (6) can be exemplified.

[0104] [Compound 11]

[0105]

[0106] (In the formula (6), R 5 is a hydrogen atom, an alkyl group having a carbon number of 1 to 20, a cycloalkyl group having a carbon number of 3 to 20, an aryl group having a carbon number of 6 to 20, an aralkyl group having a carbon number of 7 to 13, a 1,3-dioxobutyl group, or a hydroxyalkyl group; R 6 ~R 9 are each independently an alkyl group having a carbon number of 1 to 6, a cycloalkyl group having a carbon number of 3 to 20, an aryl group having a carbon number of 6 to 12, or an aralkyl group having a carbon number of 7 to 13; Y 1 is a single bond, a carbonyl group, **-(CH2) n -O- (wherein n is an integer of 1 to 4), -O-, or **-CONH-; "**" indicates a bond to the nitrogen atom in the formula (6); Y 2 ~Y 5 are each independently a single bond, a carbonyl group, -CH2-CO-, or -CH2-CH(OH)-; R 10 ~R 13 are each independently a hydrogen atom, a hydroxyl group, or a monovalent organic group; "*" indicates a bond)

[0107] In the formula (6), as the alkyl group having a carbon number of 1 to 20 and the alkyl moiety of the hydroxyalkyl group for R 5 , for example, the following can be mentioned: a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and the like. These can be linear or branched. As the cycloalkyl group having a carbon number of 3 to 20, for example, the following can be mentioned: a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a methylcyclohexyl group, and the like.

[0108] As the aryl group having a carbon number of 6 to 20, for example, the following can be mentioned: a phenyl group, a 3-fluorophenyl group, a 3-chlorophenyl group, a 4-chlorophenyl group, a 4-isopropylphenyl group, a 4-n-butylphenyl group, a 3-chloro-4-methylphenyl group, a 4-pyridyl group, a 2-phenyl-4-quinolyl group, a 2-(4'-tert-butylphenyl)-4-quinolyl group, a 2-(2'-thiophenyl)-4-quinolyl group, and the like. As the aralkyl group having a carbon number of 7 to 13, for example, the following can be mentioned: a benzyl group, a phenethyl group, and the like.

[0109] As the alkyl group having a carbon number of 1 to 6, the aryl group having a carbon number of 6 to 12, and the aralkyl group having a carbon number of 7 to 13 for R 6 ~R 9 , the compounds exemplified in the above description of R 5 as the alkyl group having a carbon number of 1 to 6, the aryl group having a carbon number of 6 to 12, and the aralkyl group having a carbon number of 7 to 13 can be mentioned, respectively.

[0110] In the formula (6), as "-Y 1 -R 5Examples of groups represented by "-Y" include: methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, octyloxy, hydroxymethyl, hydroxyethyl, hydroxypropyl, formyl, acetyl, cyclohexyl, cyclohexyloxy, phenyl, benzyl, 1,3-dioxobutyl, 1,4-dioxobutyl, 4-pyridylcarbonyl, benzoyl, 2-phenyl-4-quinolinyl, 2-(4'-tert-butylphenyl)-4-quinolinyl, 2-(2'-thiophenyl)-4-quinolinyl, and groups represented by the formula "-CONH-Ph" (where Ph is phenyl, 3-fluorophenyl, 3-chlorophenyl, 4-chlorophenyl, 4-isopropylphenyl, 4-n-butylphenyl, or 3-chloro-4-methylphenyl)". 1 -R 5 The radical represented is preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkyloxy group having 3 to 10 carbon atoms, or a hydroxyoxy group having 1 to 10 carbon atoms.

[0111] In the above formula (6), "-Y" is used as the meaning of "-Y". 2 -R 6 "-Y" 3 -R 7 "-Y" 4 -R 8 "-Y" 5 -R 9 The groups represented by "-Y" can be listed as follows: methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-butyl, isobutyl, tert-butyl, phenyl, benzyl, benzoyl, 4-formylbenzoyl, 2-hydroxy-2-phenylethyl, 2-oxo-2-(3,4,5-trimethoxyphenyl)ethyl, etc. Furthermore, "-Y" 2 -R 6 "-Y" 3 -R 7 "-Y" 4 -R 8 " and "-Y 5 -R 9 "They can be the same or different." -Y 2 -R 6 "-Y" 3 -R 7 "-Y" 4 -R 8 "-Y" 5 -R 9 The group represented is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and even more preferably an alkyl group having 1 to 3 carbon atoms.

[0112] In R 10 ~R13 As the monovalent organic group, for example, an alkyl group having 1 to 20 carbons, a cycloalkyl group having 3 to 20 carbons, an aryl group having 6 to 20 carbons, an aralkyl group having 7 to 13 carbons, a hydroxyalkyl group, and the like can be exemplified.

[0113] Compound (H) is formulated into the present alignment agent as a light stabilizer. It is considered that if a radical is generated in an alignment film containing polymer (P) by irradiation with ultraviolet rays or heat application, a new radical or a peroxide is generated based on the radical, thereby causing a functional decrease of the alignment film. In contrast, it is considered that, in the case where a liquid crystal alignment film is formed using the present alignment agent, compound (H) functions as a radical scavenger that inactivates a radical generated by ultraviolet rays or heat in the liquid crystal alignment film.

[0114] In terms of further improvement in light resistance and voltage holding property of a liquid crystal element, compound (H) is preferably one having a hydroxyl group. It is considered that, in the case where compound (H) has a hydroxyl group, the hydroxyl group of compound (H) reacts with a carboxyl group of polymer (P) by heating at the time of film formation, and compound (H) also functions as an acid deactivator. In addition, by bonding of compound (H) to one or both of polymer (P) and compound (Q), compound (H) can be inhibited from remaining in the film as a low molecular component, and even after application of a light stress to a liquid crystal alignment film or a liquid crystal cell, a liquid crystal element having high voltage holding property and excellent light resistance can be obtained. The position of the hydroxyl group in compound (H) is not particularly limited. Compound (H) can have a hydroxyl group in a moiety of the formula (6) or in a moiety different from the moiety represented by the formula (6). 5 In terms of further improvement in light resistance and voltage holding property of a liquid crystal element, compound (H) is preferably one having a hydroxyl group. It is considered that, in the case where compound (H) has a hydroxyl group, the hydroxyl group of compound (H) reacts with a carboxyl group of polymer (P) by heating at the time of film formation, and compound (H) also functions as an acid deactivator. In addition, by bonding of compound (H) to one or both of polymer (P) and compound (Q), compound (H) can be inhibited from remaining in the film as a low molecular component, and even after application of a light stress to a liquid crystal alignment film or a liquid crystal cell, a liquid crystal element having high voltage holding property and excellent light resistance can be obtained. The position of the hydroxyl group in compound (H) is not particularly limited. Compound (H) can have a hydroxyl group in a moiety of the formula (6) or in a moiety different from the moiety represented by the formula (6).

[0115] In terms of further improvement in light resistance and voltage holding property of a liquid crystal element, compound (H) is preferably one having a hydroxyl group. It is considered that, in the case where compound (H) has a hydroxyl group, the hydroxyl group of compound (H) reacts with a carboxyl group of polymer (P) by heating at the time of film formation, and compound (H) also functions as an acid deactivator. In addition, by bonding of compound (H) to one or both of polymer (P) and compound (Q), compound (H) can be inhibited from remaining in the film as a low molecular component, and even after application of a light stress to a liquid crystal alignment film or a liquid crystal cell, a liquid crystal element having high voltage holding property and excellent light resistance can be obtained. The position of the hydroxyl group in compound (H) is not particularly limited. Compound (H) can have a hydroxyl group in a moiety of the formula (6) or in a moiety different from the moiety represented by the formula (6).

[0116] As specific examples of the compound (H), for example, 4-hydroxy-1-(2-hydroxyethyl)-2,2,6,6-tetramethylpiperidine, 4-hydroxy-2,2,6,6-tetramethylpiperidine, a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinoethanol, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, 1,2,2,6,6-pentamethyl-4-piperidyl, 2,2,6,6-tetramethyl-4-piperidyl, carbonic acid bis(2,2,6,6-tetramethyl-1-undecyloxy-piperidin-4-yl) ester, pentamethylpiperidyl methacrylate, tetramethylpiperidyl methacrylate, N,N',N",N"'-tetra-(4,6-bis-(butyl-(N-methyl-2,2,6,6-tetramethylpiperidin-4-yl)amino)-triazin-2-yl)-4,7-diazadecane-1,10-diamine, a polycondensate of dibutylamine 1,3,5-triazine N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, and the like can be exemplified.

[0117] As commercially available products of light stabilizers, for example, Adekastab LA-52, LA-57, LA-63, LA-68, LA-72, LA-77, LA-81, LA-82, LA-87, LA-402, LA-40, LA-502 (all of which are manufactured by ADEKA), CHIMASSORB 119, CHIMASSORB 944, CHIMASSORB 2020, TINUVIN 111, TINUVIN 123, TINUVIN 144, TINUVIN 171, TINUVIN 249, TINUVIN 292, TINUVIN 622, TINUVIN 765, TINUVIN 770, TINUVIN 783, TINUVIN 791, TINUVIN 5100, TINUVIN XT 55 (all of which are manufactured by BASF Japan), and the like can be exemplified.

[0118] In the present alignment agent, from the viewpoint of sufficiently obtaining the improvement effect on the light resistance of the liquid crystal element, the content of the compound (H) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and further preferably 5 parts by mass or more, with respect to 100 parts by mass of the total of the polymer components contained in the present alignment agent. In addition, from the viewpoint of securing the liquid crystal alignment properties and voltage holding properties of the liquid crystal element, the content of the compound (H) is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 25 parts by mass or less, with respect to 100 parts by mass of the total of the polymer components contained in the present alignment agent. As the compound (H), one kind alone can be used, or two or more kinds can be used in combination.

[0119] <Compound (Q)>

[0120] The compound (Q) is a compound having two or more of at least one selected from the group consisting of an oxiranyl group, an oxetanyl group, a partial structure represented by the following formula (7), a partial structure represented by the following formula (8), and a partial structure represented by the following formula (9) (hereinafter, also referred to as "specific structure G") in one molecule, and not having an aromatic ring.

[0121] [Chemical Formula 12]

[0122]

[0123] (In the formulae (7) to (9), R 14a , R 14b , R15a 15b 16a 16b 17a 17b 4 6 14a 14b 15a 15b 16a 16b 17a 17b 4 6

[0124] 14a 14b 15a 15b 16a 16b 17a 17b 14a 14b 15a 15b 16a 16b 17a 17b

[0125] 4 4 4 4

[0126] [Chem. 13]

[0127]

[0128] ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​(In the formulae (L4-1) to (L4-10), "*" represents a bond)

[0129] as L 5 and L 6 As specific examples of the case where L 1 to L 3 are the same as the groups exemplified as the thermally dissociable group represented by the formulae (2) to (4) in the description of the formulae (2) to (4).

[0130] Compound (Q) is formulated into the present alignment agent as an acid deactivator that deactivates the carboxyl group possessed by polymer (P). Here, it is considered that compound (H) that is a component of the present alignment agent exhibits basicity and forms a salt under acidic conditions. In that case, the radical capturing ability of compound (H) decreases. In view of this, it is considered that in a liquid crystal alignment agent that contains polymer (P) having an amide acid structure, by containing compound (Q) as an acid deactivator, the acid (carboxyl group) derived from polymer (P) is deactivated, and the decrease in the function of compound (H) can be suppressed.

[0131] The number of the specific structure G possessed by compound (Q) in one molecule is only required to be one or more. From the viewpoint of sufficiently obtaining the improvement effect on the light resistance of the liquid crystal element, the number of the specific structure G is preferably two or more, and more preferably three or more. In addition, in the liquid crystal element, from the viewpoint of securing good liquid crystal alignment properties and voltage holding properties, the number of the specific structure G is preferably ten or less, and more preferably eight or less.

[0132] From the viewpoint of well maintaining the storage stability of the present alignment agent, and at the same time, the reactivity with the carboxyl group generated by heating at the time of film formation being high, the specific structure G possessed by compound (Q) is preferably an oxiranyl group, an oxetanyl group, the partial structure represented by the formula (7), and the partial structure represented by the following formula (8), and more preferably an oxiranyl group and an oxetanyl group, and particularly preferably an oxiranyl group.

[0133] As specific examples of the compound (Q), compounds having an epoxy group (oxiranyl group, oxetanyl group) can be exemplified by, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N-diglycidyl-benzylamine, N,N-diglycidyl-aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine, glycidyloxymethyltrimethoxysilane, glycidyloxymethyltriethoxysilane, 2-glycidyloxyethyltrimethoxysilane, 2-glycidyloxyethyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3,3'-(1,3-(2-methylene)propanediylbis(oxy methylene))bis-(3-ethyloxetane), 1,2-bis[(3-ethyl-3-oxetanylmethoxy)methyl]ethane, 1,3-bis[(3-ethyl-3-oxetanylmethoxy)methyl]propane, ethylene glycol bis(3-ethyl-3-oxetanylmethyl)ether, dicyclopentenyl bis(3-ethyl-3-oxetanylmethyl)ether, triethylene glycol bis(3-ethyl-3-oxetanylmethyl)ether, tetraethylene glycol bis(3-ethyl-3-oxetanylmethyl)ether, trimethylolpropane tris(3-ethyl-3-oxetanylmethyl)ether, 1,4-bis(3-ethyl-3-oxetanylmethoxy)butane, 1,6-bis(3-ethyl-3-oxetanylmethoxy)hexane, pentaerythritol tris(3-ethyl-3-oxetanylmethyl)ether, pentaerythritol tetra(3-ethyl-3-oxetanylmethyl)ether, dipentaerythritol hexa(3-ethyl-3-oxetanylmethyl)ether, dipentaerythritol penta(3-ethyl-3-oxetanylmethyl)ether, dipentaerythritol tetra(3-ethyl-3-oxetanylmethyl)ether, di-trimethylolpropane tetra(3-ethyl-3-oxetanylmethyl)ether, di[2-(3-oxetanyl)butyl]ether, 1,6-bis[(3-ethyloxetan-3-yl)methoxy]-2,2,3,3,4,4,5,5-octafluorohexane, 3(4),8(9)-bis[(1-ethyl-3-oxetanyl)methoxymethyl]-tricyclo[5.2.1.0 2,6decane, 2,3-bis[(3-ethyloxetan-3-yl)methoxymethyl]norbornane, 2-ethyl-2-[(3- ethyloxetan-3-yl)methoxymethyl]-1,3-O-bis[(1 -ethyl-3-oxetanyl)methyl]-propane-1,3- diol, 2,2-dimethyl-1,3-O-bis[(3-ethyloxetan-3-yl)methyl]-propane-1,3-diol, 2-butyl-2- ethyl-1,3-O-bis[(3-ethyloxetan-3-yl)methyl]-propane-1,3-diol, 1,4-O-bis[(3- ethyloxetan-3-yl)methyl]-butane-1,4-diol, oxetanylsilsesquioxane, silanol salt of 3- ethyl-3-hydroxymethyloxetane, and the like.

[0134] In addition, as commercially available products of the compound (Q), for example, Denacol EX611, Denacol EX612, Denacol EX614, Denacol EX622, Denacol EX512, Denacol EX621, Denacol EX411, Denacol EX421, Denacol EX313, Denacol EX321, Denacol EX201, Denacol EX211, Denacol EX212, Denacol EX252, Denacol EX911, Denacol EX941, Denacol EX920, Denacol EX931, Denacol EX111, Denacol EX121, Denacol EX141, Denacol EX142, Denacol EX146, Denacol EX192, Denacol EX721, Denacol EX203, Denacol EX711, Denacol EX147, Denacol EX221, Denacol EX150, Denalex R45EPT, Denalex EX810, Denalex EX811, Denalex EX850, Denalex EX851, Denalex EX821, Denalex EX830, Denalex EX832, Denalex EX841, Denalex EX861, Denalex EX145, Denalex EX147 (manufactured by Nagase Chemtex Corporation), Arone Oxetane OXT-121 (XDO), Arone Oxetane 221 (DOX), HQOX, RSOX, CTOX, 4,4'-BPOX, 2,2'-BPOX, TM-BPOX, 2,7-NpDOX, OFH-DOX, NDMOX, TMPTOX, NPGOX, BisAOX, BisFOX, PNOX, CNOX, OX-SQ, OX-SC (all manufactured by Toagosei Co., Ltd.), ETARNACOLL OXBP (all manufactured by Ube Industries, Ltd.), and the like. In addition, as the compound (Q), a polyorganosiloxane containing an epoxy group described in International Publication No. 2009 / 096598 can also be used.

[0135] As the compound having the partial structure represented by the formula (7), a multifunctional aliphatic alcohol and a multifunctional aliphatic alcohol having a protected hydroxyl group can be exemplified. In the partial structure represented by the formula (7), the bonding bond "*" in the formula (7) is preferably bonded to a nitrogen atom. Among them, the compound having the partial structure represented by the formula (7) is preferably a compound having a partial structure represented by the following formula (7-1), and more preferably a compound having two or more partial structures represented by the following formula (7-1) in one molecule.

[0136] [Chemical Formula 14]

[0137]

[0138] (In the formula (7-1), Z 1 is a monovalent group represented by the formula (7); "*" represents a bonding bond)

[0139] As specific examples of the compound having the partial structure represented by the formula (7), for example, compounds represented by the following formulae (q-1-1) to (q-1-4), and the like can be exemplified.

[0140] [Chemical Formula 15]

[0141]

[0142] (In the formulae (q-1-3) and (q-1-4), L 7 is a hydrogen atom or a thermally dissociable group; among them, one or more of the plurality of L 7 in the formula are thermally dissociable groups; the plurality of L 7 in the formula are the same as or different from each other)

[0143] As the compound having at least one selected from the group consisting of the partial structure represented by the formula (8) and the partial structure represented by the formula (9), a polyfunctional aliphatic amine and a polyfunctional aliphatic amine having a protected amino group can be exemplified. In the case where the compound (Q) has the partial structure represented by the formula (8), the partial structure represented by the formula (9), or both of these, at least one selected from the group consisting of a polyfunctional chain amine, a polyfunctional chain amine having a protected amino group, and a polyfunctional heterocyclic amine having an isocyanurate ring can be preferably used, and at least one selected from the group consisting of a polyfunctional chain amine and a polyfunctional chain amine having a protected amino group is more preferable.

[0144] As the specific examples of the compound (Q), for example, the compounds represented by the following formulae (q-2-1) to (q-2-12), and the like can be exemplified.

[0145] [Chemical Formula 16]

[0146]

[0147] [Chemical Formula 17]

[0148]

[0149] (In the formulae (q-2-7) to (q-2-12), L 8 is a hydrogen atom or a thermally dissociable group; wherein, in the formula, a plurality of L 8 are a thermally dissociable group; in the formula, a plurality of L 8 are the same as or different from each other

[0150] In the alignment agent, from the viewpoint of sufficiently obtaining the improvement effect on the light resistance of the liquid crystal element, the content of the compound (Q) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and further preferably 5 parts by mass or more, relative to 100 parts by mass of the total of the polymer components contained in the alignment agent. In addition, from the viewpoint of securing the liquid crystal alignment property and the voltage holding property of the liquid crystal element, the content of the compound (Q) is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 25 parts by mass or less, relative to 100 parts by mass of the total of the polymer components contained in the alignment agent. As the compound (Q), one kind can be used alone, or two or more kinds can be used in combination.

[0151] <Other Components>

[0152] The liquid crystal alignment agent of the present disclosure can further contain a component other than the polymer (P), the compound (H), and the compound (Q) (hereinafter, also referred to as "other component"). As the other component, for example, a polymer not having the partial structure (X) (hereinafter, also referred to as "other polymer"), an ultraviolet absorber, an antioxidant can be exemplified.

[0153] (other polymer)

[0154] The main skeleton of the other polymer to be formulated in the present alignment agent is not particularly limited. As the other polymer, for example, a polyamide acid, a polyamide acid ester, a polyimide, a polyorganosiloxane, a polyester, a polyalkenylamine, a polyurea, a polyamide, a polyamide-imide, a polybenzoxazole precursor, a polybenzoxazole, a cellulose derivative, a polyacetal, a (meth)acrylic polymer, a styrene polymer, a maleimide polymer, a styrene-maleimide copolymer, and the like can be exemplified. From the viewpoint of obtaining a liquid crystal element with high reliability, the other polymer is preferably at least one selected from the group consisting of a polyamide acid, a polyamide acid ester, a polyimide, a polyorganosiloxane, and a polymer containing a structural unit derived from a monomer having a polymerizable unsaturated carbon-carbon bond, and more preferably at least one selected from the group consisting of a polyamide acid, a polyamide acid ester, and a polyimide. As the polymer containing a structural unit derived from a monomer having a polymerizable unsaturated carbon-carbon bond, a (meth)acrylic polymer, a styrene polymer, a maleimide polymer, and a styrene-maleimide copolymer, and the like can be exemplified.

[0155] In the case of forming a liquid crystal alignment film using a photoalignment method, a polymer having a photoalignment site can also be used as the other polymer. As specific examples of the photoalignment site possessed by the other polymer, the same groups as exemplified for the photoalignment site that the polymer (P) can have can be exemplified. Among these, the photoalignment site possessed by the other polymer is preferably a cyclobutane ring structure-containing group containing a cyclobutane ring structure as a basic skeleton, more preferably a group represented by the formula (9) or the formula (10), and further preferably a group represented by the formula (10). Among these, from the viewpoint of high photosensitivity, the photoalignment site possessed by the other polymer is particularly preferably a structure unit derived from 1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride.

[0156] In the case where the liquid crystal alignment agent contains the other polymer, the content of the other polymer is preferably 5% by mass or more, and more preferably 10% by mass or more, relative to the total amount of the polymer (P) and the other polymer. In addition, the content of the other polymer is preferably 99% by mass or less, and more preferably 97% by mass or less, relative to the total amount of the polymer (P) and the other polymer. As the other polymer, one kind alone can be used, or two or more kinds can be used in combination.

[0157] <Ultraviolet Absorber>

[0158] Examples of ultraviolet absorbers formulated in this orientation agent include: azobenzene compounds, indole compounds, triazine compounds, benzotriazole compounds, anthocyanin compounds, oxazole compounds, naphthylimide compounds, oxadiazole compounds, oxazine compounds, oxazolidine compounds, anthracene compounds, and benzophenone compounds. Among these, compounds having one or more absorption maxima in the wavelength range of 290 nm to 420 nm are preferably used. In particular, the ultraviolet absorber formulated in this orientation agent is preferably at least one selected from the group consisting of triazine compounds and benzotriazole compounds, and especially preferably a triazine compound.

[0159] Specific examples of triazine compounds and benzotriazole compounds include the compounds represented by formulas (U-1) to (U-4) below.

[0160] [Chemistry 18]

[0161]

[0162] (In equations (U-1) to (U-3), R) a1 Each of the following is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 8 carbon atoms, a substituted or unsubstituted alkenyl group having 3 to 8 carbon atoms, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms, a substituted or unsubstituted alkylaryl group having 7 to 18 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 18 carbon atoms; R a1 ~R a9 Each of the following is independently composed of a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 15 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an alkenyl group having 3 to 8 carbon atoms, an aryl group having 6 to 18 carbon atoms, an alkylaryl group having 7 to 18 carbon atoms, or an arylalkyl group having 7 to 18 carbon atoms.

[0163] [Chemistry 19]

[0164]

[0165] (In formula (U-4), R) b1 ~R b3 Each of the following is independently composed of a hydrogen atom, a halogen atom, a hydroxyl group, an aralkyl group, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, or an alkoxycarbonylalkyl group having 1 to 18 carbon atoms.

[0166] In equations (U-1) to (U-3), in R a1 In the case of substituted alkyl, cycloalkyl, alkenyl, aryl, alkylaryl, and arylalkyl groups, as Ra1 Examples of the alkyl group, the cycloalkyl group, the alkenyl group, the aryl group, the alkylaryl group, and the arylalkyl group include any of the hydrogen atoms of the groups substituted with a hydroxyl group, a halogen atom, and any of the methylene groups substituted with an oxygen atom, a sulfur atom, a carbonyl group, an ester group, an amide group, or an imine group.

[0167] As specific examples of the ultraviolet absorber, commercially available products such as Adekastab LA-24, LA-29, LA-31, LA-32, LA-36, LA-46, LA-F70, 1413 (manufactured by ADEKA Corporation), Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 329, Tinuvin 360, Tinuvin 1577ED, Tinuvin 1600, Chimassorb 81, Tinuvin PS, Tinuvin 99-2, Tinuvin 384-2, Tinuvin 900, Tinuvin 928, Tinuvin 1130, Tinuvin 970, Tinuvin 400, Tinuvin 405, Tinuvin 460, Tinuvin 477, Tinuvin 479, Tinuvin B 75, UVA-903KT, UVA-935LH, UVA-805 (manufactured by BASF Japan Ltd.), and the like can be exemplified.

[0168] In the case where the ultraviolet absorber is contained in the present orienting agent, from the viewpoint of maintaining a good voltage holding property even after application of light stress and sufficiently obtaining an improvement effect of light resistance, the content of the ultraviolet absorber is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and further preferably 2 parts by mass or more, relative to 100 parts by mass of the total of the polymer components contained in the present orienting agent. In addition, from the viewpoint of securing the liquid crystal alignment property and the voltage holding property of the liquid crystal element, the content of the ultraviolet absorber is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and further preferably 10 parts by mass or less, relative to 100 parts by mass of the total of the polymer components contained in the present orienting agent. As the ultraviolet absorber, one kind can be used alone, or two or more kinds can be used in combination.

[0169] <Antioxidant>

[0170] As the antioxidant to be compounded in the alignment agent, at least one selected from the group consisting of phenol-based antioxidants and phosphorus-based antioxidants can be preferably used. By containing these antioxidants in the alignment agent, even in the case where the liquid crystal element is continuously driven for a long time in a harsh environment of light, heat, humidity, or the like, a good voltage holding property can be maintained, which is suitable in this respect.

[0171] As the phenol-based antioxidant, for example, tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-isocyanurate, tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)-butane, 4,4'-butylidenebis(6-tert-butyl-m-cresol), 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid stearyl ester, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene, thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide], isooctyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 4,6-bis(dodecylthiomethyl)-o-cresol, 4,6-bis(octylthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, and the like can be exemplified.

[0172] As commercially available products of the phenol-based antioxidant, for example, Adekastab AO-20, Adekastab AO-30, Adekastab AO-40, Adekastab AO-50, Adekastab AO-60, Adekastab AO-80, Adekastab AO-330 (all of which are manufactured by ADEKA Corporation), IRGANOX 1010, IRGANOX 1035, IRGANOX 1076, IRGANOX 1098, IRGANOX 1135, IRGANOX 1330, IRGANOX 1726, IRGANOX 1425, IRGANOX 1520, IRGANOX 245, IRGANOX 259, IRGANOX 3114, IRGANOX 3790, IRGANOX 5057, IRGANOX 565, I RGAMOD 295 (all of which are manufactured by BASF Japan Ltd.), and the like can be mentioned.

[0173] As the phosphorus-based antioxidant, for example, 3,9-bis(4-nonylphenoxy)-2,4,8,10-tetraoxa-3,9-diphospha- spiro[5.5]undecane, 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphospha-spiro[5.5]undecane, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphospha-spiro[5.5]undecane, 2,4,8,10-tetra(1,1-dimethylethyl)-6-[(2-ethylhexyl)oxy]-12H-dibenzo[d,g][1,3,2]dioxaphosphepin, tris(2,4-di-tert-butylphenyl)phosphite, tetrakis(2,4-di-tert-butyl-5-methylphenyl)[1,1-biphenyl]-4,4'-diylbisphosphonite, tris[2-[[2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]ethyl]amine, bis(2,4-di-tert-butylphenyl)pentaerythrityl diphosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethylphosphite, and the like can be mentioned.

[0174] As commercially available products of phosphorus-based antioxidants, for example, Adekastab PEP-4C, Adekastab PEP-8, Adekastab PEP-36, HP-10, 2112, 1178, 1500, C, 135A, 3010, TPP (all of which are manufactured by Adeka Corporation), GSY-P101 (manufactured by Sakai Chemical Industry Co., Ltd.), IRGAFOS 168, IRGAFOS 12, IRGAFOS 126, IRGAFOS 38, IRGAFOS P-EPQ (all of which are manufactured by BASF Japan Ltd.), and the like can be exemplified.

[0175] In the case where an antioxidant is contained in the present orienting agent, from the viewpoint of obtaining a liquid crystal element that exhibits a good voltage holding property even after light stress is applied to a liquid crystal alignment film, the content of the antioxidant is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and further preferably 2 parts by mass or more, relative to 100 parts by mass of the total of the polymer components contained in the present orienting agent. In addition, from the viewpoint of maintaining the liquid crystal alignment property of the liquid crystal element well, the content of the antioxidant is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and further preferably 10 parts by mass or less, relative to 100 parts by mass of the total of the polymer components contained in the present orienting agent. As the antioxidant, one kind alone can be used, or two or more kinds can be used in combination.

[0176] In the present orienting agent, as components that are formulated as additives together with the polymer (A), in addition to the above, for example, a functional silane compound, a compound having one or more (meth)acryloyl groups in the molecule, a metal chelate compound, a hardening accelerator, a surfactant, a filler, a dispersant, and the like can be exemplified. As for each component, the content in the present orienting agent can be appropriately selected according to each compound within a range that does not impair the effects of the present disclosure.

[0177] (Solvent)

[0178] The liquid crystal alignment agent of the present disclosure is preferably prepared in the form of a liquid composition in which the polymer (P), the compound (H), the compound (Q), and other components as necessary are dispersed or dissolved in a suitable solvent.

[0179] 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. These can be used alone or in combination of two or more.

[0180] The solid content concentration in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent in the liquid crystal alignment agent in the total mass of the liquid crystal alignment agent) is 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 applied to the surface of a substrate as described later, preferably with heating, thereby forming a coating film that is or becomes a liquid crystal alignment film. At this time, if the solid content concentration is 1 mass% or more, the film thickness of the coating film can be sufficiently ensured, and is appropriate in terms of easily obtaining a good liquid crystal alignment film. In addition, if the solid content concentration is 10 mass% or less, the film thickness of the coating film is not excessively large, a good liquid crystal alignment film can be obtained, and the viscosity of the liquid crystal alignment agent can be appropriately ensured, and the application properties can be made good.

[0181] In terms of sufficiently obtaining the effects of the present disclosure, the content of the polymer (P) in the liquid crystal alignment agent is preferably 0.5 mass% or more, more preferably 1 mass% or more, and further preferably 2 mass% or more, with respect to 100 mass parts of the total of the solid components (i.e., components other than the solvent) in the liquid crystal alignment agent. In addition, the content of the polymer (P) is preferably 90 mass% or less, and more preferably 60 mass% or less, with respect to 100 mass parts of the total of the solid components in the liquid crystal alignment agent.

[0182] Liquid crystal alignment film and liquid crystal element

[0183] 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 for example, 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 Electrically Controlled Birefringence (ECB) mode, an In-Plane Switching (IPS) mode, a Fringe Field Switching (FFS) mode, an Optically Compensated Bend (OCB) mode, and the like can be applied. 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. Process 2 and Process 3 are common to each mode of operation.

[0184] (Process 1: Formation of a Film)

[0185] First, a liquid crystal alignment agent is applied to a substrate, and preferably the coated 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; a transparent substrate including polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly(alicyclic olefin), or the like can be used. 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 type, a STN type, or a VA type, 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 type or an FFS type, 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 by a flexographic printing method, a spin coating method, a roll coater method, or an inkjet printing method.

[0186] After the application of the liquid crystal alignment agent, 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 30°C to 200°C, and more preferably 40°C to 150°C. The pre-baking time is preferably 0.25 minutes to 10 minutes. Thereafter, a calcination (post-baking) process is performed for the purpose of completely removing the solvent and, as necessary, thermally imidizing an amic acid structure present in the polymer. The calcination temperature (post-baking temperature) at this time is preferably 80°C to 280°C, and more preferably 80°C to 250°C. The post-baking time is preferably 5 minutes to 200 minutes. The film thickness of the film thus formed is preferably 0.001 μm to 1 μm. After the application of the liquid crystal alignment agent 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.

[0187] (Step 2: alignment treatment)

[0188] In the case of manufacturing a liquid crystal element of a TN type, a STN type, an IPS type, or an FFS type, a treatment for imparting a liquid crystal alignment ability to the coating film formed in the above-described Step 1 (alignment treatment) is performed. Thus, a liquid crystal alignment ability is imparted to the coating film to become a liquid crystal alignment film. As the alignment treatment, a rubbing treatment using cotton or the like to rub the surface of the coating film formed on the substrate, or a photo-alignment treatment for imparting a liquid crystal alignment ability by light irradiation to the coating film is preferably used. In the case of manufacturing a liquid crystal element of a 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.

[0189] 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 the pre-baking step, the post-baking step, or both. 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 used is linearly polarized or partially polarized, the irradiation can be performed from a direction perpendicular to the substrate surface, from an inclined direction, or a combination thereof. In the case where the radiation is not polarized, the irradiation direction is set to an inclined direction.

[0190] 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 warmed.

[0191] In the production of a liquid crystal alignment film, the organic film subjected to the light irradiation treatment can be further subjected to heating. By the heating treatment (heating re-alignment), a liquid crystal element in which the liquid crystal alignment property is further improved can be obtained, which is preferred in this respect. The heating can be post-baking or a heating treatment performed separately from the post-baking after the post-baking. From the viewpoint of promoting the re-alignment of the molecular chains based on the heating, the heating temperature is preferably 80°C to 280°C, more preferably 80°C to 250°C. The heating time is preferably 5 minutes to 200 minutes, more preferably 10 minutes to 60 minutes.

[0192] In the production of the liquid crystal alignment film, a contact 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 be further included. As the water-soluble organic solvent, for example, methanol, ethanol, 1-propanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone can be exemplified. As the method of contact of the organic film with the solvent, for example, a spray treatment, a shower treatment, an immersion treatment, a liquid coating treatment, and the like can be exemplified, but are not limited thereto. The contact time of the organic film with the solvent is not particularly limited, and for example, is 5 seconds to 15 minutes. The heating treatment of the organic film can be performed after the contact step.

[0193] (Step 3: Construction of Liquid Crystal Cell)

[0194] Two substrates each of which the liquid crystal alignment film is formed in the above-described manner are prepared, and a liquid crystal is disposed between the two substrates disposed in opposition to each other, whereby a liquid crystal cell is produced. In the production of the liquid crystal cell, for example, (1) a method in which two substrates are disposed in opposition to each other with a gap (spacer) 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 on which the liquid crystal alignment film is formed, and then liquid crystal is dropped at prescribed several places on the surface of the liquid crystal alignment film, and the other substrate is bonded in opposition to the liquid crystal alignment film, and the liquid crystal is allowed to spread over the entire surface of the substrate, and the like can be exemplified. It is preferable that, for the produced 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 further performed, whereby the flow alignment at the time of filling of the liquid crystal is removed.

[0195] As the sealant, for example, a hardening agent and an epoxy resin containing alumina balls as spacers can be used. As the spacers, a photospacer, a bead spacer, and the like can be used. The liquid crystal alignment film formed of the liquid crystal alignment agent of the present disclosure is excellent in light resistance, and thus, in the case where the sealed structure of the liquid crystal cell is formed by light hardening of the sealant, the step of shielding the disposition region (display region) of the liquid crystal can be omitted.

[0196] As the liquid crystal, either of a positive type and a negative type can be used. In the case of using a negative type liquid crystal in a liquid crystal element of an IPS type and an FFS type, the transmission loss of the upper portion of the electrode can be reduced, and the contrast ratio can be improved, and thus the negative type liquid crystal is preferred in this respect. In addition, as the liquid crystal to be used, a nematic liquid crystal, a smectic liquid crystal, and the like can be exemplified, and the nematic liquid crystal is preferred. As the nematic liquid crystal, for example, a Schiff base type liquid crystal, an azoxy type liquid crystal, a biphenyl type liquid crystal, a phenylcyclohexane type liquid crystal, an ester type liquid crystal, a terphenyl type liquid crystal, a biphenylcyclohexane type liquid crystal, a pyrimidine type liquid crystal, a dioxane type liquid crystal, a bicyclooctane type liquid crystal, a cubane type liquid crystal, and the like can be used. In addition, a cholesteric liquid crystal, a chiral reagent, a ferroelectric liquid crystal, and the like can be added to these liquid crystals and used.

[0197] 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" in which polyvinyl alcohol is extended and oriented and iodine is absorbed is sandwiched by a cellulose acetate protective film or a polarizing plate including the H film itself can be exemplified. Thus, a liquid crystal element is obtained.

[0198] The liquid crystal element of the present disclosure can be effectively applied to various uses, and for example, 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, or the like, or a dimming film or the like. 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.

[0199] [Examples]

[0200] Hereinafter, the present application will be described more specifically by examples, but the present application is not limited to these examples.

[0201] <Structure of Compounds and Abbreviations>

[0202] The structure and abbreviations of the main compounds used in the following examples are as follows.

[0203] [Dicarboxylic Acids]

[0204] TA-1: 1,2,3,4-cyclobutane tetracarboxylic dianhydride

[0205] TA-2: (1R, 2R, 3S, 4S)-1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic acid dianhydride

[0206] TA-3: 2,3,5-tricarboxycyclopentylacetic acid dianhydride

[0207] [Chem. 20]

[0208]

[0209] [DIAMINE]

[0210] DA-1: N,N'-bis(5-aminopyridin-2-yl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine

[0211] DA-2: tert-butyl(4-aminobenzyl)(4-aminophenethyl)carbamate

[0212] DA-3: 1,5-bis(5-aminobenzimidazol-1-yl)pentane

[0213] DA-4: p-phenylenediamine

[0214] DA-5: 2,2'-dimethylbenzidine

[0215] DA-6: 4,4'-diaminodiphenylmethane

[0216] DA-7: 4,4'-diaminodiphenylether

[0217] DA-8: O,O'-bis(4-aminophenyl)-ethanediol

[0218] DA-9: N1,N6-bis(4-aminophenethyl)-N1,N6-di(tert-butoxycarbonyl)adipic diamide

[0219] DA-10: N4,N4'-bis(4-aminophenyl)-N4,N4'-dimethylbenzidine

[0220] [Chem. 21]

[0221]

[0222] [Compound (H): Hindered amine-based light stabilizer]

[0223] H-1: Adekastab LA-72 (manufactured by ADEKA Corporation)

[0224] H-2: Adekastab LA-77Y (manufactured by ADEKA Corporation)

[0225] H-3: Tinuvin 123 (manufactured by BASF Corporation)

[0226] H-4: 4-Hydroxy-1-(2-hydroxyethyl)-2,2,6,6-tetramethylpiperidine

[0227] H-5: 4-Hydroxy-2,2,6,6-tetramethylpiperidine

[0228] H-6: Chimassorb 944 (manufactured by BASF Corporation)

[0229] H-7: Tinuvin 152 (manufactured by BASF Corporation)

[0230] [Chemical 22]

[0231]

[0232] [Compound (Q): Acid deactivator]

[0233] Q-1: Shofree PETG (manufactured by Showa Denko Corporation)

[0234] Q-2: Denacol EX-614B (manufactured by Nagase Chemtex Corporation)

[0235] Q-3: Denacol EX-512 (manufactured by Nagase Chemtex Corporation)

[0236] Q-4: N1,N1,N6,N6-tetrakis(2-hydroxyethyl)adipoyldiamine

[0237] Q-5: Tert-butyl bis(6-((tert-butoxycarbonyl)amino)hexyl)carbamate

[0238] [Chemical 23]

[0239]

[0240] [Compound (U): Ultraviolet absorber]

[0241] U-1: Tinuvin 405 (manufactured by BASF Corporation)

[0242] U-2: Tinuvin 928 (manufactured by BASF Corporation)

[0243] U-3: 2,2',4,4'-Tetrahydroxybenzophenone

[0244] [Chemical 24]

[0245]

[0246] [Compound (A): Antioxidant]

[0247] A-1 : 2,6-di-tert-butyl-4-methoxyphenol

[0248] A-2: Triphenyl phosphite

[0249] [Chemical 25]

[0250]

[0251] [Other additives]

[0252] AD-1 : Dipentaerythritol hexaacrylate

[0253] AD-2: N,N'-1,3-phenylene dimaleimide

[0254] AD-3: N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl methane

[0255] AD-4: 2,2'-(1,3-phenylene) bis(2-oxazoline)

[0256] [Chemical 26]

[0257]

[0258] [Solvents]

[0259] NMP: N-methyl-2-pyrrolidone

[0260] GBL: γ-butyrolactone

[0261] DAA: Diacetone alcohol

[0262] BC: Butyl cellosolve

[0263] <Synthesis and evaluation of polymers>

[0264] In the following Synthesis Example 1 to Synthesis Example 6, polymers were respectively synthesized. Further, in the following examples, the imidization rate of polyimide in a polymer solution was measured by the following method.

[0265] [Imidization rate of polyimide]

[0266] A solution of polyimide was poured into pure water, and the obtained precipitate was sufficiently dried under reduced pressure at room temperature, and then dissolved in deuterated dimethyl sulfoxide, and the amount of hydrogen was measured at room temperature with tetramethylsilane as a reference substance. 1 H-nuclear magnetic resonance1 H-Nuclear magnetic resonance, 1 H-NMR). The imidization ratio [%] was calculated from the obtained 1 H-NMR spectrum (400 MHz) and was calculated by the following equation (1).

[0267] Imidization ratio [%] = (1 - (A1 / (A2 x a))) x 100 (1)

[0268] (Equation (1), A1 is the peak area of the proton derived from the amide group appearing near the chemical shift of 10 ppm, A2 is the peak area of the proton derived from the aromatic group appearing near the chemical shift of 6 ppm to 9 ppm, and a is the number ratio of the protons of the aromatic group to 1 proton of the amide group in the precursor of the polymer (polyamic acid))

[0269] [Synthesis Example 1]

[0270] A diamine (diamine (DA-1) 50 parts by mole and diamine (DA-5) 50 parts by mole) was dissolved in NMP, and 0.95 molar equivalents of tetracarboxylic dianhydride (TA-2) was added with respect to the total amount of the diamine, and a reaction was performed at room temperature for 6 hours to obtain a solution of polyamic acid. In the obtained solution, 0.80 molar equivalents of 1-methylpiperidine and acetic anhydride as a dehydrating agent were added with respect to the carboxyl group of the polyamic acid, and heating and stirring were performed at 60°C for 3 hours. The obtained solution was repeatedly subjected to concentration under reduced pressure and dilution with NMP to obtain a 10 mass% solution of polyimide (PI-1) having a partial structure represented by the following formula (PI-1). The imidization ratio of the polyimide (PI-1) was 78%.

[0271] [Chemical Formula 27]

[0272]

[0273] [Synthesis Example 2]

[0274] A diamine (diamine (DA-4) 100 parts by mole) was dissolved in NMP, and 0.95 molar equivalents of tetracarboxylic dianhydride (TA-2) was added with respect to the total amount of the diamine, and a reaction was performed at room temperature for 6 hours to obtain a 15 mass% solution of polyamic acid (PI-2) having a partial structure represented by the following formula (PI-2).

[0275] [Chemical Formula 28]

[0276]

[0277] [Synthesis Examples 3 to 6]

[0278] The kind of tetracarboxylic dianhydride and diamine and the molar ratio were changed as described in Table 1 below, and otherwise, the same as in Synthesis Example 2 was performed to obtain polyamic acid (PI-3 to PI-6). Further, regarding the values in Table 1, for the acid dianhydride, the use ratio (mol%) of each compound with respect to the total amount (100 mol%) of the acid dianhydride used in the synthesis is indicated, and for the diamine, the use ratio (mol%) of each compound with respect to the total amount (100 mol%) of the diamine used in the synthesis is indicated.

[0279] [Table 1]

[0280]

[0281] Preparation and evaluation of liquid crystal alignment agent

[0282] [Example 1: Optically oriented FFS-type liquid crystal display element]

[0283] (1) Preparation of liquid crystal alignment agent

[0284] A polymer component (converted to solid content: polymer (PI-1) 5 parts by mass, polymer (PI-5) 95 parts by mass, light stabilizer (H-1) 10 parts by mass, and acid deactivator (Q-1) 10 parts by mass) was diluted with NMP, GBL, DAA, and BC, whereby a solution having a solid content concentration of 4.0% by mass and a solvent composition ratio of NMP:GBL:DAA:BC=30:30:30:10 (mass ratio) was obtained. The solution was filtered with a filter having a pore size of 0.2 μm, whereby a liquid crystal alignment agent (AL-1) was prepared.

[0285] (2) Formation of liquid crystal alignment film by optical orientation method

[0286] The liquid crystal alignment agent (AL-1) prepared in the above (1) was applied to each of the face of a glass substrate on which a flat plate electrode, an insulating layer, and a comb-tooth electrode were sequentially layered on one face, and the face of an opposing glass substrate on which no electrode was provided, using a spin coater, and after heating on a hot plate at 80°C for 1 minute, heating was performed in an oven at 230°C for 30 minutes under nitrogen substitution in the oven, whereby a coating film having an average film thickness of 100 nm was formed. The surface of the coating film was irradiated with ultraviolet rays including a bright line at 254 nm polarized by a straight line at 300 mJ / cm2from the normal direction of the substrate using a Hg-Xe lamp, and the like, and an optical orientation treatment was performed. The coating film on which the optical orientation treatment was performed was heat-treated by heating in an oven at 230°C for 30 minutes under nitrogen substitution in the oven, whereby a liquid crystal alignment film was formed. 2 The coating film on which the optical orientation treatment was performed was heat-treated by heating in an oven at 230°C for 30 minutes under nitrogen substitution in the oven, whereby a liquid crystal alignment film was formed.

[0287] (3) Manufacture of FFS-type liquid crystal display element

[0288] The periphery of the face of one of the substrates produced in the (2) having the liquid crystal alignment film had a liquid crystal injection port, and an epoxy resin adhesive in which alumina balls having a diameter of 3.5 μm were put was applied using a dispenser, after which the faces of the pair of substrates having the liquid crystal alignment film were made to face each other in a manner such that the alignment treatment directions of the respective substrates became antiparallel, and were press-bonded, and the adhesive was thermally cured at 150°C for 1 hour. Subsequently, a negative nematic liquid crystal (manufactured by Merck, MJ20195NCMP) was filled into the gap between the substrates from the liquid crystal injection port, after which the liquid crystal injection port was sealed using an epoxy-based adhesive. Further, in order to remove the flow alignment at the time of liquid crystal injection, heating was performed at 120°C, after which slow cooling to room temperature was performed. Subsequently, polarizing plates were attached to the outer sides of the substrates in a manner such that their polarizing directions were orthogonal to each other and formed an angle of 45° with the alignment treatment direction of the liquid crystal alignment film, thereby producing an FFS-type liquid crystal display element.

[0289] (4) Evaluation of liquid crystal alignment properties

[0290] With respect to the liquid crystal display element produced in the (3), the presence or absence of abnormal domains in the bright-dark change at the time of turning on / off (application / removal) of a voltage of 5 V was observed using a microscope at a magnification of 50 times. With respect to the evaluation, the case where no abnormal domains were observed was taken as "good", and the case where abnormal domains were observed was taken as "poor". As a result, the evaluation was "good" in the present example.

[0291] (5) Evaluation of voltage holding ratio and light resistance

[0292] A pair of substrates coated with a liquid crystal alignment agent was changed to a glass substrate having an ITO electrode, and a liquid crystal alignment film was formed in the same manner as in (2) above. Also, a pair of substrates used in the production of a liquid crystal display element was changed to a glass substrate having an ITO electrode on which a liquid crystal alignment film was formed, and an ECB (electrically controlled birefringence) type liquid crystal display element was produced by performing the same operations as in (3) above. With respect to the liquid crystal display element, light irradiation was performed for 168 hours on a backlight with a cold cathode tube (cold cathode fluorescent lamp (CCFL)) as a light source. With respect to the liquid crystal display element after light irradiation, after a voltage of 1 V was applied at 60 microseconds of application time and 1670 milliseconds of span at 70°C, the voltage retention rate after 1670 milliseconds from the removal of the application was measured, and the result was 77%. In the evaluation of light resistance, a voltage retention rate of 80% or more was rated as "excellent", a voltage retention rate of more than 70% and less than 80% was rated as "good", and a voltage retention rate of less than 70% was rated as "poor". The result was "good" in the evaluation in this example. Further, as a device for measuring the voltage retention rate, a model name "VHR-1" manufactured by Toyo Technica (K.K.) was used.

[0293] [Examples 2 to 15, Comparative Examples 1 to 14]

[0294] In the example 1, the components contained in the liquid crystal alignment agent were changed as shown in Table 2 below, and otherwise, the liquid crystal alignment agent was prepared in the same manner as in Example 1, and a liquid crystal alignment film was formed by the photo-alignment method, and FFS type liquid crystal display elements and ECB type liquid crystal display elements were produced, and various evaluations were performed. The results of the evaluations are shown in Table 2 below.

[0295] [Example 16: Rubbing alignment FFS type liquid crystal display element]

[0296] (1) Preparation of liquid crystal alignment agent

[0297] A polymer component (solid component conversion: polymer (PI-4) 40 parts by mass, polymer (PI-6) 60 parts by mass, light stabilizer (H-4) 10 parts by mass, and acid deactivator (Q-1) 10 parts by mass) was diluted with NMP, GBL, DAA, and BC, whereby a solution having a solid component concentration of 4.0% by mass and a solvent composition ratio of NMP:GBL:DAA:BC=30:30:30:10 (mass ratio) was obtained. The solution was filtered with a filter having a pore size of 0.2 μm, whereby a liquid crystal alignment agent (AL-30) was prepared.

[0298] (2) Formation of liquid crystal alignment film by rubbing method

[0299] The liquid crystal alignment agent (AL-30) prepared in the above (1) was coated on each of the surfaces of a pair of glass substrates on which a flat electrode, an insulating layer, and a comb-tooth electrode were sequentially layered on one surface, and a facing glass substrate on which no electrode was provided, using a spin coater, and heated on a hot plate at 80°C for 1 minute, and then heated in an oven at 230°C under nitrogen replacement in the oven for 30 minutes, to thereby form a coating film having an average film thickness of 100 nm. The surface of the coating film was subjected to rubbing treatment twice using a rubbing machine having a roller on which a nylon cloth was wound, at a roller rotation number of 1000 rpm, a stage moving speed of 30 mm / sec, and a bristle penetration length of 0.3 mm. The coating film subjected to the rubbing alignment treatment was subjected to ultrasonic cleaning in ultrapure water for 1 minute, and then dried in an oven at 100°C for 10 minutes, to thereby form a liquid crystal alignment film.

[0300] (3) Production of FFS-type liquid crystal display element

[0301] A FFS-type liquid crystal display element was produced in the same manner as in Example 1, except that a pair of substrates having the liquid crystal alignment film produced in the above (2) was used.

[0302] (4) Evaluation of liquid crystal alignment property

[0303] The FFS-type liquid crystal display element produced in the above (3) was evaluated for liquid crystal alignment property in the same manner as in Example 1. As a result, the evaluation was "good" in this example.

[0304] (5) Evaluation of voltage holding ratio and light resistance

[0305] An ECB-type liquid crystal display element was produced in the same manner as in Example 1, except that a pair of substrates used in the production of the liquid crystal display element was changed to a liquid crystal alignment film formed by a rubbing method, and the light resistance was evaluated based on the voltage holding ratio. As a result, the evaluation was "good" in this example.

[0306] [Table 2]

[0307]

[0308] In Table 2, the mass ratio of each component of the liquid crystal alignment agent indicates the blending ratio (mass parts) of each compound with respect to 100 mass parts of the total of the polymer component and the additive component used in the production of the liquid crystal alignment agent.

[0309] As shown in Table 2, in the liquid crystal alignment agents of Examples 1 to 16 containing the polymer (P), the light stabilizer (H), and the acid deactivator (Q), the liquid crystal alignment properties of the liquid crystal display elements were all "good", and the light resistance was all "excellent" or "good", and the balance between the liquid crystal alignment properties and the light resistance was achieved. In contrast, in the liquid crystal alignment agents of Comparative Examples 1 to 14 not containing the polymer (P), the light stabilizer (H), or the acid deactivator (Q), or not containing two or more of these, the liquid crystal alignment properties of the liquid crystal display elements were "good", but the light resistance was evaluated as "poor", which was inferior to that of Examples 1 to 16.

[0310] In the liquid crystal alignment agent containing the polymer (P), the light stabilizer (H), and the acid deactivator (Q), the mechanism is not certain, but it is presumed that the radicals generated by light excitation are captured by the synergistic effect of these three components, and thus the radical decomposition of the liquid crystal alignment film is inhibited, and the light resistance is improved.

[0311] In detail, the light stabilizer (H) exhibits basicity, and forms a salt under acidic conditions, and thus the radical capturing ability tends to decrease. In addition, in the liquid crystal alignment agent containing the polyamic acid, the imidization reaction proceeds by heating at the time of forming the liquid crystal alignment film, but the carboxyl group derived from the polyamic acid tends to remain without being completely eliminated. Therefore, it is considered that the light stabilizer (H) incorporated in the liquid crystal alignment agent reacts with the carboxyl group derived from the polyamic acid to form a salt, and thus the radical capturing ability by the light stabilizer (H) decreases.

[0312] Here, in Examples 1 to 16, since the polymer (P) has a partial structure (aliphatic amino group, pyridine ring, benzimidazole ring) exhibiting basicity, it is considered that the acid derived from the polyamic acid is deactivated in the liquid crystal alignment film, and the polymer is crosslinked by ionic bonds. On the other hand, in Comparative Example 14, the polymer (PI-2) and the polymer (PI-5) do not have a partial structure exhibiting basicity, and thus it is considered that the acid derived from the polyamic acid remains in the liquid crystal alignment film.

[0313] Further, by incorporating the acid deactivator (Q) in the liquid crystal alignment agent, the reaction of the carboxyl group derived from the polyamic acid with the acid deactivator (Q) proceeds by heating at the time of forming the liquid crystal alignment film, and an ester or a carboxylate is generated, and thus it is considered that the acid derived from the polyamic acid is partially deactivated. In addition, the acid deactivator (Q) has two or more functional groups, and thus a covalent bond or an ionic bond is formed by the reaction, and thus it can be said that the polymer is crosslinked.

[0314] Thus, it is presumed that in the liquid crystal alignment agent containing the light stabilizer (H), the activity of the light stabilizer (H) is improved by neutralizing the acid in the liquid crystal alignment film by including the polymer (P) and the acid deactivator (Q), and thus the light resistance of the liquid crystal display element is improved. In addition, it is presumed that by cross-linking the polymer constituting the liquid crystal alignment film, the swelling of the alignment film caused by the liquid crystal is suppressed, and the movement of substances such as impurity ions taken into the film is suppressed, and thus the voltage holding ratio of the liquid crystal display element is improved.

[0315] In addition, it is considered that a liquid crystal composition having an alkenyl structure or the like as a liquid crystal is oxidatively decomposed under light irradiation to produce an acidic decomposition product such as formic acid, and it is possible to decrease the electrical characteristics or the light resistance of the liquid crystal element. In contrast, it is presumed that in the case where the polymer (P) and the acid deactivator (Q) coexist, the basic functional group possessed by the polymer (P) is not bound by the acid in the liquid crystal alignment film, and can act as a free base, and can capture an acidic decomposition product or the like derived from the liquid crystal.

[0316] On the other hand, in the case where a phenol-based antioxidant or a phosphorus-based antioxidant is formulated instead of the light stabilizer (H), the light resistance of the liquid crystal display element is not improved (Comparative Examples 6 to 9). It is considered that this is because the generation of peroxide is small in the liquid crystal cell, and the effect is not exhibited in the phenol-based antioxidant or the phosphorus-based antioxidant.

[0317] In addition, it is known that the light resistance is slightly improved by using the ultraviolet absorber (U) in the present alignment agent (Example 10, Example 11). With regard to this, it is presumed that in addition to the inhibition of the radical decomposition reaction of the liquid crystal alignment film by the light stabilizer (H), the production of radicals caused by photoexcitation is inhibited by the ultraviolet absorber (U), and thus the light resistance is further improved.

[0318] On the other hand, as shown in Comparative Examples 10 to 13, in the additives (AD-1) to (AD-4), the improvement in the light resistance by the use in combination with the light stabilizer is limited. It is considered that the reason is that the additives (AD-1) and (AD-2) do not react with the carboxyl group of the polyamic acid, and cannot deactivate the acid in the liquid crystal alignment film. In addition, it is considered that the additives (AD-3) and (AD-4) react with the carboxyl group of the polyamic acid, but the improvement in the light resistance is not observed. The main reason for the improvement in the light resistance in the acid deactivator (Q) having an aliphatic structure for the additives (AD-3) and (AD-4) having an aromatic structure is not certain, but it is predicted that the main reason is that the light absorption of the acid deactivator (Q) having an aliphatic structure is small, the molecular mobility in the alignment film is high, and the reaction rate with the carboxyl group is high.

[0319] [Examples 17 to 20]

[0320] The components contained in the liquid crystal alignment agent were changed as shown in Table 3 below, and otherwise, the liquid crystal alignment agent was prepared in the same manner as in Example 1, and a liquid crystal alignment film was formed by the photo-alignment method, and FFS-type liquid crystal display elements and ECB-type liquid crystal display elements were manufactured, and various evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 3 below.

[0321] [Examples 21 to 24]

[0322] The components contained in the liquid crystal alignment agent were changed as shown in Table 3 below, and otherwise, the liquid crystal alignment agent was prepared in the same manner as in Example 16, and a liquid crystal alignment film was formed by the rubbing method, and FFS-type liquid crystal display elements and ECB-type liquid crystal display elements were manufactured, and various evaluations were performed in the same manner as in Example 16. The evaluation results are shown in Table 3 below.

[0323] [Table 3]

[0324]

[0325] In Table 3, the mass ratio of each component of the liquid crystal alignment agent indicates the blending ratio (mass parts) of each compound with respect to 100 mass parts of the total of the polymer component and the additive component used in the preparation of the liquid crystal alignment agent.

[0326] Further, it is presumed that in a liquid crystal display element formed using a liquid crystal alignment agent containing a polymer (P) having a cyclobutane ring structure, the light resistance is easily reduced due to a photodecomposition reaction. In contrast, in the case of using a liquid crystal alignment agent containing a polymer (P) having a cyclobutane ring structure, and a light stabilizer (H) and an acid deactivator (Q) together, the light resistance of the liquid crystal display element is improved as a result.

[0327] According to the above, it is known that according to the liquid crystal alignment agent of the present disclosure containing a polymer (P), a light stabilizer (H), and an acid deactivator (Q), the deterioration of the liquid crystal alignment film (decomposition of the liquid crystal alignment film, etc.) is suppressed by the synergistic effect of these three components, and the light resistance of the liquid crystal element can be improved. In addition, it is known that a liquid crystal element including a liquid crystal alignment film formed from the liquid crystal alignment agent of the present disclosure also exhibits a high voltage holding ratio after imparting a light stress.

Claims

1. A liquid crystal alignment agent, comprising: The polymer (P) has a partial structure represented by the following formula (1); Compound (H), having a hindered amine structure and a partial structure represented by the following formula (6); and Compound (Q) has, within one molecule, at least two aggregates selected from the group consisting of ethylene oxide, oxetyl, partial structures represented by formula (7), partial structures represented by formula (8), and partial structures represented by formula (9), and does not have an aromatic ring. Relative to the total 100 parts by mass of the polymer components contained in the liquid crystal alignment agent, the content of compound (H) is 1 part by mass or more and 40 parts by mass or less, and the content of compound (Q) is 1 part by mass or more and 40 parts by mass or less. The proportion of a diamine compound having at least one selected from the group consisting of the partial structure represented by formula (2), the partial structure represented by formula (3), the partial structure represented by formula (4), and the partial structure represented by formula (5) is 2 mol% or more and 80 mol% or less, relative to the total amount of diamine compounds used in the synthesis of the polymer (P). In formula (1), X 1 is a substituted or unsubstituted tetravalent alicyclic hydrocarbon group; X 2 is a divalent group having at least one selected from the group consisting of a partial structure represented by the following formula (2), a partial structure represented by the following formula (3), a partial structure represented by the following formula (4), and a partial structure represented by the following formula (5), In formulae (2) to (5), R 1a , R 1b , R 2a , R 2b , R 3a , R 3b , R 4a , and R 4b are each independently a hydrogen atom or a monovalent aliphatic hydrocarbon group having a carbon number of 1 to 8; L 1 and L 2 are each independently a hydrogen atom, a thermally dissociable group, or a monovalent hydrocarbon group; L 3 is a hydrogen atom, a thermally dissociable group, or a monovalent aliphatic hydrocarbon group; Ar 1 is a divalent aromatic group; Ar 2 is a divalent group obtained by removing two hydrogen atoms from a ring portion of a nitrogen-containing heteroaromatic ring. " indicates a bond. In formula (7) to formula (9), R 14a , R 14b , R 15a , R 15b , R 16a , R 16b , R 17a , and R 17b are each independently a hydrogen atom or a monovalent organic group which is an alkyl group having a carbon number of 1 to 20; L 4 to L 6 are each independently a hydrogen atom or a thermally dissociable group; wherein, R 14a , R 14b , R 15a , R 15b , R 16a , R 16b , R 17a , R 17b and L 4 ~ L 6 do not have an aromatic ring. " represents a bond. In formula (6), R 5 is a hydrogen atom, an alkyl group having a carbon number of 1 to 20, a cycloalkyl group having a carbon number of 3 to 20, an aryl group having a carbon number of 6 to 20, an aralkyl group having a carbon number of 7 to 13, a 1,3-dioxobutyl group, or a hydroxyalkyl group; R 6 ~R 9 are each independently an alkyl group having a carbon number of 1 to 6, a cycloalkyl group having a carbon number of 3 to 20, an aryl group having a carbon number of 6 to 12, or an aralkyl group having a carbon number of 7 to 13; Y 1 is a single bond, a carbonyl group, wherein n is an integer of 1 to 4, -O-, or -CONH-;" " indicates a bond to the nitrogen atom in formula (6); Y 2 ~Y 5 are each independently a single bond, a carbonyl group, -CH2-CO-, or -CH2-CH(OH)-; R 10 ~R 13 are each independently a hydrogen atom, a hydroxyl group, or an alkyl group having a carbon number of 1 to 20;" " indicates a bond.

2. The liquid crystal alignment agent according to claim 1, wherein the polymer (P) is a polymer having photo-alignment sites.

3. The liquid crystal aligning agent according to claim 1 or 2, further comprising a polymer having a photo-orientation site, wherein, Except for the polymer (P).

4. The liquid crystal aligning agent according to claim 1 or 2, wherein the X 1 is a tetravalent organic group having a cyclobutane ring structure.

5. The liquid crystal alignment agent according to claim 1 or 2, wherein the compound (H) has a hydroxyl group.

6. The liquid crystal alignment agent according to claim 1 or 2, wherein the compound (H) has at least one selected from the group consisting of a triazine ring structure and a benzotriazole ring structure.

7. The liquid crystal alignment agent according to claim 1 or 2, further comprising an ultraviolet absorber as a component different from the polymer (P), the compound (H) and the compound (Q).

8. A liquid crystal alignment film formed using a liquid crystal alignment agent as described in any one of claims 1 to 7.

9. A liquid crystal element comprising the liquid crystal alignment film as described in claim 8.

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