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

Abstract

This invention provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal element. It can obtain a liquid crystal element with good liquid crystal alignment, high voltage retention, and low image retention, and can form a liquid crystal alignment film with high film strength, good reprocessability, and good adhesion. This invention contains a polymer [P] in the liquid crystal alignment agent having a partial structure (A) represented by formula (1) or formula (2) at the end of the main chain. In formulas (1) and (2), R... 1 and R 5 It is a monovalent organic group that is deactivated by at least one of heat and light. R 2 It is a monovalent organic group. (i)R 6 It is a monovalent organic group, R 7 It is a divalent alicyclic group, or (ii)R 6 and R 7 R represents 6 and R 7 A ring structure formed together with the bonded nitrogen atoms.

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] Liquid crystal elements are applied to a wide range of uses from relatively large display devices such as liquid crystal televisions and information displays to small display devices such as smart phones. The performance of a liquid crystal element is determined by various characteristics such as the alignment property of liquid crystals, the magnitude of a pretilt angle, and the voltage holding ratio. In order to improve the performance of a liquid crystal element, in addition to improvements in liquid crystal materials, improvements in liquid crystal alignment films for aligning liquid crystals in a certain direction have been made in the past (for example, refer to Patent Literature 1 and Patent Literature 2).

[0003] In Patent Literature 1, it is disclosed that a liquid crystal alignment film is formed using a polyimide precursor and a polyimide having a structure in which an amino group bonded to a methylene group is protected with a t-butyloxy carbonyl (Boc) group in a side chain of a polymer. In addition, in Patent Literature 2, it is disclosed that a Boc group is introduced at the end of the main chain of a polyamic acid by reacting the polymerized polyamic acid with di-t-butyl dicarbonate, and a liquid crystal alignment film is formed using the polymer.

[0004] [Prior Art Documents]

[0005] [Patent Literature]

[0006] [Patent Literature 1] International Publication No. 2010 / 050523

[0007] [Patent Literature 2] International Publication No. 2019 / 022215 SUMMARY

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

[0009] In recent years, with the high definition of liquid crystal elements, the quality requirements have become more stringent. In order to meet such requirements, liquid crystal elements are required to have further improved liquid crystal alignment properties, voltage holding ratios, and residual image characteristics (difficulty of occurrence of residual images). In addition, when considering the application of a rubbing method, the improvement of liquid crystal alignment properties and voltage holding ratios, the suppression of yield reduction, and the like, it is required that an organic film formed using a liquid crystal alignment agent has sufficiently high strength.

[0010] In a liquid crystal display device, in order to secure a display region as large as possible, a method of forming a liquid crystal alignment film over the entire surface of a substrate, applying a sealing material over the liquid crystal alignment film, and adhering the substrates to each other is employed, so that a narrow frame of a liquid crystal panel is achieved. In such a structure, a portion of the liquid crystal alignment film where the sealing material is provided is easily subjected to stress, and in the case where the adhesion of the liquid crystal alignment film to the substrate is poor, peeling of the liquid crystal alignment film from the sealing material portion is likely to occur, and the reliability of the liquid crystal element can be reduced.

[0011] In the manufacturing process of a liquid crystal alignment film, defects such as a pinhole or uneven coating of the liquid crystal alignment film formed over a substrate are sometimes generated, and an operation of peeling the liquid crystal alignment film from the substrate and reusing (reworking) the substrate is often performed. At the time of such reworking, it is required that the coating film can be easily peeled from the substrate (i.e., the reworkability is good).

[0012] However, it is difficult to satisfy the plurality of characteristics at the same time, and there is room for further improvement of the liquid crystal alignment agent.

[0013] The present application was made in view of the above-described problems, and a main object thereof is to provide a liquid crystal alignment agent, which can achieve a liquid crystal element having good liquid crystal alignment properties, a high voltage holding ratio, and less image sticking, and can form a liquid crystal alignment film having high film strength, good reworkability, and good adhesion.

[0014] [Means for solving the problems]

[0015] The present inventors have made earnest research in order to solve the above-described problems, and as a result, have found that the above-described problems can be solved by using a polymer having a specific structure at the terminal of a main chain, and have completed the present application. Specifically, the present application provides the following means.

[0016] <1> A liquid crystal alignment agent containing a polymer [P] having a partial structure (A) represented by the following formula (1) or formula (2) at the terminal of a main chain.

[0017] [Chemical Formula 1]

[0018]

[0019] (In formula (1), R 1 is a monovalent organic group which is detached by at least one of heat and light. R 2 is a monovalent organic group. R 3 and R 4 are each independently a hydrogen atom or a monovalent organic group. "*" represents a bond.

[0020] In formula (2), R 5 is a monovalent organic group which is detached by at least one of heat and light. R 6 and R 7(i) or (ii) below is satisfied.

[0021] (i) R 6 is a monovalent organic group. R 7 is a divalent alicyclic group.

[0022] (ii) R 6 and R 7 represent R 6 and R 7 form a ring structure together with the nitrogen atom to which they are bonded.

[0023] " " represents a bond.

[0024] <2> A liquid crystal alignment agent containing a polymer [P] obtained by polymerizing monomers including a tetracarboxylic dianhydride, at least one acid derivative selected from the group consisting of tetracarboxylic dianhydride and tetracarboxylic diester dihalide, and a diamine compound in the presence of a monoamine compound having a partial structure (A) represented by the formula (1) or formula (2) below, or by polymerizing the monomers and then reacting with the monoamine compound.

[0025] <3> A liquid crystal alignment film formed using the liquid crystal alignment agent of <1> or <2>.

[0026] <4> A liquid crystal element including the liquid crystal alignment film of <3>.

[0027] [Effects of the Invention]

[0028] The liquid crystal alignment agent according to the present application makes it possible to obtain a liquid crystal element that has good liquid crystal alignment properties, a high voltage holding ratio, and is less likely to produce residual images. In addition, it makes it possible to form a liquid crystal alignment film that has high film strength, good reworkability, and good close contact properties. DETAILED DESCRIPTION

[0029] [LIQUID CRYSTAL ALIGNMENT AGENT]

[0030] Hereinafter, each component contained in the liquid crystal alignment agent of the present disclosure, and other components that are optionally blended as necessary, will be described.

[0031] Further, in the present specification, the "hydrocarbon group" is a concept including a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The "chain hydrocarbon group" means a straight-chain hydrocarbon group and a branched-chain hydrocarbon group each of which main chain does not contain a cyclic structure and is composed of only a chain structure. Among them, it can be either saturated or unsaturated. The "alicyclic hydrocarbon group" means a hydrocarbon group which contains only an alicyclic hydrocarbon structure as a ring structure, and does not contain an aromatic ring structure. Among them, it is not necessary to be composed of only an alicyclic hydrocarbon structure, and a group having a chain structure in a part thereof is also included. The "aromatic hydrocarbon group" means a hydrocarbon group which contains an aromatic ring structure as a ring structure. Among them, it is not necessary to be composed of only an aromatic ring structure, and a chain structure or an alicyclic hydrocarbon structure can be contained in a part thereof. The "aromatic ring" is a concept including an aromatic hydrocarbon ring and an aromatic heterocyclic ring. The "organic group" means a group obtained by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound).

[0032] The liquid crystal alignment agent of the present disclosure contains a polymer [P] having a partial structure represented by the following formula (1) or formula (2) (hereinafter also referred to as "partial structure (A)") at a terminal of a main chain.

[0033] [Chemical Formula 2]

[0034]

[0035] (In formula (1), R 1 is a monovalent organic group which is dissociated by at least one of heat and light. R 2 is a monovalent organic group. R 3 and R 4 are each independently a hydrogen atom or a monovalent organic group. "*" represents a bond.

[0036] In formula (2), R 5 is a monovalent organic group which is dissociated by at least one of heat and light. R 6 and R 7 satisfy the following (i) or (ii).

[0037] (i) R 6 is a monovalent organic group. R 7 is a divalent alicyclic group.

[0038] (ii) R 6 and R 7 represent a ring structure formed together with the nitrogen atom to which they are bonded. 6 and R 7 represent a ring structure formed together with the nitrogen atom to which they are bonded.

[0039] "*" represents a bond.

[0040] < Polymer [P] >

[0041] • Regarding the partial structure (A)

[0042] In equations (1) and (2), R 1 and R 5 The monovalent organic group represented is preferably a group that is thermally decoupled and replaced by a hydrogen atom (hereinafter also referred to as a "thermally decoupled group"). In R 1 and R 5 When the monovalent organic group represented is a thermally detachable group, it is preferable to make R by heating (post-baking) during film formation. 1 R 5 The indicated radical is detached and can be replaced by a hydrogen atom. In this case, it is preferable in terms of simplifying the process and introducing part of the structure (A) into the main chain end of the polymer.

[0043] Specific examples of thermally detachable groups include: tert-butoxycarbonyl, benzyloxycarbonyl, 1,1-dimethylpropynyloxycarbonyl, 1,1-dimethyl-2-haloethoxycarbonyl, allyloxycarbonyl, ethyleneoxycarbonyl, cyclohexyloxycarbonyl, methylcyclohexyloxycarbonyl, 2-(trimethylsilyl)ethoxycarbonyl, 9-fluorenylmethoxycarbonyl, 2,2,2-trichloroethoxycarbonyl, phthaloyl, p-toluenesulfonyl, 2-nitrobenzenesulfonyl, etc. Among these, from the viewpoint of detaching them through heating during film formation, R... 1 R 5 The thermally detachable group is preferably a group that detaches at a temperature of 130°C to 250°C. Specifically, tert-butoxycarbonyl and 9-fluorenylmethoxycarbonyl are preferred, and tert-butoxycarbonyl (Boc group) is particularly preferred in terms of its excellent thermal detachability and ability to reduce the amount of detached structure remaining in the film.

[0044] As R in the above equation (2) 6 and R 7 When R satisfies (i) 6 The monovalent organic group represented, and R in the formula (1) 2 The monovalent organic group represented is preferably a monovalent chain hydrocarbon group with 1 or more carbon atoms, and the carbon-carbon bonds of the chain hydrocarbon group with 2 or more carbon atoms have -O-, -S-, -CO-, -COO-, or -NR. 8a -、-CO-NR 8a -、-NR 8a -CO-O- or -NR 8a -CO-NR 9a - a monovalent base (where R is a monovalent base) 8a and R 9a Each can be independently a hydrogen atom or a monovalent organic group. (The same applies below). As R 8a and R 9aThe monovalent organic group is preferably a monovalent hydrocarbon group with 1 to 10 carbon atoms, or a monovalent thermally detachable group, and more preferably an alkyl group with 1 to 3 carbon atoms or a Boc group.

[0045] In addition, -COO- and -CO-NR 8a -、-NR 8a -CO-O- and -NR 8a -CO-NR 9a - The orientation of the bond is not determined. Therefore, for example, R in equation (1) 2 In the case where a monovalent group -COO- is present between carbon-carbon bonds of a chain hydrocarbon group with more than 2 carbon atoms, -COO- can be configured as -CO- on the nitrogen atom side in formula (1) or as -O- on the nitrogen atom side in formula (1).

[0046] As R in the above equation (2) 6 and R 7 When R satisfies (i) 6 The monovalent organic group represented, and R in the formula (1) 2 The monovalent organic group represented, from the viewpoint of improving the reactivity of the nitrogen atom in the formula (1), is preferably an alkyl group having 1 to 5 carbon atoms, or a monovalent group having -O- between the carbon-carbon bonds of the alkyl group, more preferably an alkyl group having 1 to 3 carbon atoms, or an alkoxyalkyl group having 1 to 3 carbon atoms.

[0047] R in equation (1) 3 and R 4 The monovalent organic group represented may include monovalent chain hydrocarbon groups with 1 to 10 carbon atoms, monovalent alicyclic hydrocarbon groups with 5 to 12 carbon atoms, monovalent aromatic hydrocarbon groups with 6 to 12 carbon atoms, and any methylene group of chain hydrocarbon groups with 2 or more carbon atoms bearing the radicals -O-, -S-, -CO-, -COO-, or -NR. 8a -、-CO-NR 8a -、-NR 8a -CO-O- or -NR 8a -CO-NR 9 - Monovalent groups formed by substitution, etc. Among these, R 3 and R 4 The monovalent organic group represented is preferably an alkyl or alkoxy group having 1 to 5 carbon atoms, and more preferably an alkyl or alkoxy group having 1 to 3 carbon atoms.

[0048] Regarding R in equation (1) 3 and R 4In terms of improving the reactivity of the nitrogen atom in the formula (1), making the liquid crystal aligning property, voltage holding ratio, image sticking property, and mechanical strength of the film better, it is preferable that the group represented by R1and R2in the formula (1) be a hydrogen atom, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, more preferably a hydrogen atom, an alkyl group or an alkoxy group having 1 to 3 carbon atoms, and further preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom.

[0049] R1and R2in the formula (2) satisfy the condition (i), as the divalent alicyclic group represented by R1and R2, for example, cyclopentane-diyl, cyclohexane-diyl, cycloheptane-diyl, or a divalent group having a methyl group, an ethyl group, a methoxy group, or the like as a substituent on the ring of these groups can be mentioned. 6 and R 7 satisfy the condition (i), as the divalent alicyclic group represented by R1and R2, for example, cyclopentane-diyl, cyclohexane-diyl, cycloheptane-diyl, or a divalent group having a methyl group, an ethyl group, a methoxy group, or the like as a substituent on the ring of these groups can be mentioned. 7 satisfy the condition (i), as the divalent alicyclic group represented by R1and R2, for example, cyclopentane-diyl, cyclohexane-diyl, cycloheptane-diyl, or a divalent group having a methyl group, an ethyl group, a methoxy group, or the like as a substituent on the ring of these groups can be mentioned.

[0050] R1and R2in the formula (2) satisfy the condition (ii), as the divalent alicyclic group represented by R1and R2, for example, a group in which a pyrrolidine ring, a piperidine ring, a hexamethylene imine ring, or a ring having a methyl group, an ethyl group, a methoxy group, or the like as a substituent on the ring of these rings has two hydrogen atoms (a hydrogen atom bonded to a nitrogen atom and a hydrogen atom bonded to a carbon atom) removed from the ring portion can be mentioned. 6 and R 7 satisfy the condition (ii), as the divalent alicyclic group represented by R1and R2, for example, a group in which a pyrrolidine ring, a piperidine ring, a hexamethylene imine ring, or a ring having a methyl group, an ethyl group, a methoxy group, or the like as a substituent on the ring of these rings has two hydrogen atoms (a hydrogen atom bonded to a nitrogen atom and a hydrogen atom bonded to a carbon atom) removed from the ring portion can be mentioned. 6 and R 7 satisfy the condition (ii), as the divalent alicyclic group represented by R1and R2, for example, a group in which a pyrrolidine ring, a piperidine ring, a hexamethylene imine ring, or a ring having a methyl group, an ethyl group, a methoxy group, or the like as a substituent on the ring of these rings has two hydrogen atoms (a hydrogen atom bonded to a nitrogen atom and a hydrogen atom bonded to a carbon atom) removed from the ring portion can be mentioned.

[0051] As specific examples of the partial structure (A), for example, the structures represented by the following formulae (A-1) to (A-15), respectively, can be mentioned.

[0052] [Chem. 3]

[0053]

[0054] [Chem. 4]

[0055]

[0056] (In the formula, TMS represents a trimethylsilyl group. "*" represents a bond.)

[0057] With respect to the partial structure (A), in terms of the effect of improving the liquid crystal aligning property, voltage holding ratio, and image sticking property, it is preferable that the partial structure represented by the formula (1) be one in which R1and R2in the formula (1) are hydrogen atoms, and more preferably a partial structure in which R1and R2in the formula (1) are hydrogen atoms. 3 and R 4 are hydrogen atoms. The partial structure (A) possessed by the polymer [P] can be one, or two or more. The number of the partial structure (A) possessed by the polymer [P] is preferably one or two.

[0058] • With respect to the polymer [P]

[0059] The main chain of the polymer [P] is not particularly limited. In terms of the affinity with liquid crystals, the high mechanical strength, and the high reliability of the liquid crystal alignment film, and in terms of the high improvement effect of various characteristics brought about by introducing the partial structure (A) into the terminal of the main chain, at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide is preferable as the polymer [P].

[0060] When the polymer [P] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, the polymer [P] can be obtained, for example, by a method including a step of polymerizing monomers including a tetracarboxylic dianhydride, an acid derivative selected from at least one of the group consisting of tetracarboxylic dianhydride and tetracarboxylic diester dihalide, and a diamine compound.

[0061] (polyamic acid)

[0062] When the polymer [P] is polyamic acid, as a method of producing the polyamic acid (hereinafter also referred to as "polyamic acid [P]"), there is no particular limitation as long as the partial structure (A) can be introduced into the terminal of the main chain. Here, the "main chain" of the polymer refers to a portion of the "trunk" including the longest atomic chain in the polymer. Furthermore, the "trunk" portion is allowed to include a ring structure. The "side chain" of the polymer refers to a portion branching from the "trunk" of the polymer.

[0063] In order to introduce the partial structure (A) into the terminal of the main chain of the polyamic acid, a method of using a compound having the partial structure (A) (hereinafter also referred to as "compound [A]") as an end-capping agent for stopping the polymerization reaction in the middle of the polymerization reaction or after the polymerization reaction can be exemplified. Specifically, the following methods [1] and [2] can be exemplified.

[0064] [1] A method of polymerizing monomers including a tetracarboxylic dianhydride and a diamine compound in the presence of the compound [A].

[0065] [2] A method of reacting a polymer obtained by polymerizing monomers including a tetracarboxylic dianhydride and a diamine compound with the compound [A] after the polymerization.

[0066] Among these methods, the method of the [1] is preferable as the production method of the polyamic acid [P]. According to the method of the [1], by reacting the terminal of the polymer (more specifically, a structural unit derived from the tetracarboxylic dianhydride) with the compound [A] in the middle of the polymerization reaction, a polymer having a structural unit derived from the compound [A] at the terminal of the main chain can be obtained as the polyamic acid [P]. Therefore, the process for introducing the partial structure (A) into the terminal of the main chain of the polyamic acid can be provided separately from the polymerization process, which is preferable in terms of the aspect of the simplification of the production process.

[0067] (tetracarboxylic dianhydride)

[0068] As the tetracarboxylic dianhydride used in the synthesis of the polyamic acid [P], for example, aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, and the like can be exemplified. As specific examples of these, the aliphatic tetracarboxylic dianhydride can include 1,2,3,4-butanetetracarboxylic dianhydride, ethylenediaminetetraacetic dianhydride, and the like; the alicyclic tetracarboxylic dianhydride can include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxylic cyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxylic bicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, 3,5,6-tricarboxylic-2-carboxymethyl norbornane-2:3,5:6-dianhydride, and the like; the aromatic tetracarboxylic dianhydride can include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol bis-trimellitate anhydride, 4,4'-carbonylbisphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and the like, and in addition to these, the tetracarboxylic dianhydride described in Japanese Patent Laid-Open No. 2010-97188 can be used. As the tetracarboxylic dianhydride, one kind alone or two or more kinds in combination can be used.

[0069] In terms of obtaining a liquid crystal alignment film that has high solubility and exhibits good liquid crystal alignment properties and electrical properties, the tetracarboxylic dianhydride used in the synthesis of the polyamic acid [P] is preferably at least one selected from the group consisting of aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, and more preferably contains alicyclic tetracarboxylic dianhydride. The proportion of the alicyclic tetracarboxylic dianhydride used is preferably 20 mol% or more, more preferably 40 mol% or more, and further preferably 50 mol% or more, relative to the total amount of the tetracarboxylic dianhydride used in the synthesis of the polyamic acid [P].

[0070] (diamine compound)

[0071] As the diamine compound used in the synthesis of the polyamic acid [P], aliphatic diamine, alicyclic diamine, aromatic diamine, diaminosilicone, and the like can be exemplified.

[0072] As specific examples of the diamine compound, aliphatic diamines can include m-xylylenediamine, hexamethylenediamine, and the like; alicyclic diamines can include 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and the like; and aromatic diamines can include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4-aminophenyl-4-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,5-bis(4-aminophenoxy)pentane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,6-bis(4-aminophenoxy)hexane, 6,6'-(pentamethylenedioxy)bis(3-aminopyridine), N,N'-bis(5-amino-2-pyridyl)-N,N'-bis(tert-butoxycarbonyl)ethylenediamine, bis[2-(4-aminophenyl)ethyl]hexanedioic acid, 4,4'-diaminodiphenylether, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenylethylurea, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-(phenylenediisopropylidene)dianiline, 2,6-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 3,6-diaminoacridine, monomers containing a diphenylamine structure (e.g., N4,N4'-bis(4-aminophenyl)-N4,N4'-dimethylphenylamine, and the like), N,N'-bis(5-aminopyridin-2-yl)-N,N'-bis(tert-butoxycarbonyl)ethylenediamine, a compound represented by the following formula (D-1)

[0073] [Chemical Formula 5]

[0074]

[0075] (In formula (D-1), R 11 and R 12 are each independently an alkanediyl group. R 13 is a hydrogen atom, an alkyl group having 1 to 3 carbons, or a protecting group. n1 is an integer of 1 to 3. In the case where n1 is 2 or 3, the plurality of R 12 are the same as or different from each other, and the plurality of R 13 are the same as or different from each other.)

[0076] a compound represented by the following formula (D-1)

[0077] Hexadecyloxy-2,4-diaminobenzene, octadecyloxy-2,4-diaminobenzene, octadecyloxy-2,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestanolyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanolyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestanol 3,5-diaminobenzoate, lanostanyl 3,5-diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestan, 3,6-bis(4-aminophenoxy)cholestan, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 3,5-diaminobenzoic acid = 5ξ-cholestan-3-yl, the following formula (E-1)

[0078] [Chemical 6]

[0079]

[0080] (In formula (E-1), X I and X II independently represent a single bond, -O-, -COO-, or -OCO- (in which, " * " represents a bonding bond with X I . 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. In which, 1 ≤ a + b + c ≤ 3.)

[0081] a side chain type diamine represented by a compound represented by the following formula (D-1) or the like,

[0082] The diaminoorganosiloxane can include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane or the like.

[0083] As the compound represented by the formula (D-1), for example, a compound represented by the following formula (D-1-1) to (D-1-3), respectively, or the like can be exemplified. As the compound represented by the formula (E-1), for example, a compound represented by the following formula (E-1-1) to (E-1-4), respectively, or the like can be exemplified. In the production of the polyamic acid [P], as a diamine compound, one kind alone or two or more in combination can be used. Further, in the structural formula, "Boc" represents tert-butoxycarbonyl (hereinafter the same).

[0084] [Chemical 7]

[0085]

[0086] (Compound [A])

[0087] Compound [A] is a compound having a partial structure (A), such as an acid monoanhydride, a monoamine compound, a monoisocyanate compound, and the like. Among these, Compound [A] is preferably a monoamine compound, and specifically, a compound represented by the following formula (3) is preferable.

[0088] [Compound 8]

[0089]

[0090] (In formula (3), A 1 is a monovalent group having the partial structure represented by the formula (1) or formula (2). R 8 is a single bond, -O-, -S-, -CO-, -COO-, -NR 10 -, -CO-NR 10 -, -NR 10 -CO-O-, -NR 10 -CO-NR 11 -, a divalent chain hydrocarbon group having 1 or more carbons, a divalent alicyclic hydrocarbon group having 3 or more carbons, or a divalent chain hydrocarbon group having 2 or more carbons, in which any methylene group of the divalent chain hydrocarbon group is substituted with -O-, -S-, -CO-, -COO-, -NR 10 -, -CO-NR 10 -, -NR 10 -CO-O-, or -NR 10 -CO-NR 11 . R 10 and R 11 are each independently a hydrogen atom or a monovalent organic group. R 9 is a single bond or an (m+1) valent aromatic ring group. m is 1 or 2. Among these, in the case where R 9 is a single bond, m is 1, and R 8 is a single bond or is bonded to the primary amino group in formula (3) via a hydrocarbon group. In the case where m is 2, a plurality of R 8 are the same or different, and a plurality of A 1 are the same or different.

[0091] In the formula (3), A 1 is a monovalent group represented by the formula (1) or formula (2). As to the specific examples and preferable examples of the formula (1) and formula (2), the description can be referred to. As the monovalent group represented by A 1 , for example, the groups represented by the formula (A-1) to formula (A-15) respectively, and the like can be exemplified.

[0092] In R 8When the hydrocarbon group is a divalent chain with one or more carbon atoms, from the viewpoint of improving reactivity with the crosslinking agent described later, the chain hydrocarbon group is preferably an alkyl group, and more preferably a straight-chain alkyl group. In R 8 In the case of a divalent chain hydrocarbon group, from the viewpoint of achieving excellent film adhesion, improving film strength (and consequently, improving friction resistance), increasing the voltage retention rate of the liquid crystal element, improving liquid crystal orientation, and improving image retention characteristics, the number of carbons in the chain hydrocarbon group is preferably 7 or less, more preferably 5 or less, and even more preferably 3 or less.

[0093] In R 8 Any methylene group present in the chain hydrocarbon group is replaced with -O-, -S-, -CO-, -COO-, -NR. 10 -、-CO-NR 10 -、-NR 10 -CO-O- or -NR 10 -CO-NR 11 When a divalent group is formed, specific examples and preferred examples of the chain-like hydrocarbon group can be found in the description above. In R 10 R 11 In the case of a monovalent organic group, examples of such monovalent organic groups include monovalent hydrocarbon groups having 1 to 10 carbon atoms, thermally detachable groups, etc. Regarding R... 10 R 11 Preferably, it is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally detachable group; more preferably, it is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a tert-butoxycarbonyl group.

[0094] In R 8 When the alicyclic hydrocarbon group has 3 or more carbon atoms, examples of such alicyclic hydrocarbon groups include 1,4-cyclohexanediyl, 2-methyl-1,4-cyclohexanediyl, and 2,5-dimethyl-1,4-cyclohexyl.

[0095] From the viewpoint of improving the reactivity with the crosslinking agent (more specifically, compound [B]) to obtain a liquid crystal element with excellent voltage retention and liquid crystal alignment, R, as described above, 8 Preferably, it is a divalent group with 1 to 7 carbons formed by replacing any methylene group in a single bond, -O-, -S-, -CO-, -COO-, alkyldiyl group with 1 to 7 carbons, or alkyldiyl group with 2 or more carbons with -O- or -S-.

[0096] In addition, -COO- and -CO-NR 10 -、-NR 10 -CO-O- and -NR 10 -CO-NR 11 - The orientation of the bond is not certain. Therefore, for example, R in equation (3) 8In the case of -COO-, -COO- can make -CO- bond with A in formula (3) 1 In the case of -COO-, -COO- can make -CO- bond with A in formula (3) 1 In the case of -COO-, -COO- can make -CO- bond with A in formula (3)

[0097] In the case of R 9 In the case of the (m+1)-valent aromatic ring group, as the aromatic ring group, a (m+1)-valent aromatic hydrocarbon group and a (m+1)-valent aromatic heterocyclic group can be exemplified. Among these, a (m+1)-valent aromatic hydrocarbon group and a (m+1)-valent nitrogen-containing aromatic heterocyclic group are preferable. R 9 The aromatic ring moiety can also have a substituent. The substituent is preferably an alkyl group having 1 to 3 carbons, an alkoxy group having 1 to 3 carbons, or a halogen atom.

[0098] As R 9 In the case of the (m+1)-valent aromatic ring group, as the (m+1)-valent aromatic hydrocarbon group, a group in which (m+1) arbitrary hydrogen atoms bonded to carbon atoms constituting a benzene ring, a biphenyl ring, a naphthalene ring, or an anthracene ring are removed can be exemplified, and as the (m+1)-valent nitrogen-containing aromatic heterocyclic group, a group in which (m+1) arbitrary hydrogen atoms bonded to carbon atoms constituting a pyridine ring, a pyrimidine ring, a pyridazine ring, or a pyrazine ring are removed can be exemplified. In the case of the (m+1)-valent aromatic ring group, R 9 In the case of the (m+1)-valent aromatic ring group, as R 9 Among these, a group in which (m+1) hydrogen atoms are removed from a substituted or unsubstituted benzene ring or a pyridine ring is preferable.

[0099] As the compound [A], among these, a compound in which A 1 In the case of the group represented by formula (1), R 8 is a single bond, -O-, -S-, -CO-, -COO-, an alkandiyl group having 1 to 7 carbons, or a divalent group having 1 to 7 carbons in which an arbitrary methylene group of an alkandiyl group having 2 or more carbons is substituted with -O- or -S-, and R 9 is a single bond or a (m+1)-valent aromatic ring group; and a compound in which A 1 In the case of the group represented by formula (2), R 8 and R 9 is a single bond.

[0100] As specific examples of the compound [A], for example, a compound represented by formula (CA-1) to formula (CA-29) described below, and the like can be exemplified. Furthermore, as the compound [A], one kind alone can be used, or two or more kinds can be used in combination.

[0101] [Chemical Formula 9]

[0102]

[0103] [Chem. 10]

[0104]

[0105] [Chem. 11]

[0106]

[0107] [Chem. 12]

[0108]

[0109] [Chem. 13]

[0110]

[0111] (In the formula, k, k1, and k2 are each independently an integer of 0 to 7.)

[0112] (Synthesis of polyamic acid)

[0113] The synthesis reaction of the polyamic acid [P] is preferably performed in an organic solvent. In the synthesis reaction of the polyamic acid [P], the ratio of the use of the tetracarboxylic dianhydride to the diamine compound is preferably 0.2 equivalents to 2 equivalents of the acid anhydride group of the tetracarboxylic dianhydride per 1 equivalent of the amino group of the diamine compound.

[0114] In the synthesis reaction, the ratio of the use of the compound [A] is preferably 1 mol% or more, more preferably 2 mol%, and further preferably 5 mol% or more, relative to the total amount of the diamine compound and the compound [A] used in the synthesis, from the viewpoint of introducing the structural unit derived from the compound [A] to the terminal of the main chain of the polymer and obtaining a polymer within an appropriate molecular weight range. In addition, the ratio of the use of the compound [A] is preferably 30 mol% or less, more preferably 20 mol% or less, and further preferably 15 mol% or less, relative to the total amount of the diamine compound and the compound [A] used in the synthesis.

[0115] Further, in the synthesis reaction, a compound having no partial structure (A) can be used together with the compound [A] as an end-capping agent. As the compound, for example, an acid monomer such as maleic anhydride, phthalic anhydride, itaconic anhydride, and the like; a monoamine compound such as aniline, cyclohexylamine, n-butylamine, and the like; a monoisocyanate compound such as phenyl isocyanate, naphthyl isocyanate, and the like can be exemplified. Among these, the ratio of the use of the compound is preferably 10 mol% or less, more preferably 5 mol% or less, and further preferably 1 mol% or less, relative to the total amount of the end-capping agents used in the synthesis reaction.

[0116] In the synthesis reaction of the polyamic acid [P], the reaction temperature 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, alcohol-based solvents, ketone-based solvents, ester-based solvents, ether-based solvents, halogenated hydrocarbons, hydrocarbons, and the like can be exemplified. Among these, it is preferable to use one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphoric triamide, m-cresol, di-m-cresol, and halogenated phenol as the reaction solvent, or a mixture of one or more of these and other organic solvents (e.g., butyl cellosolve, diethylene glycol diethyl ether, and the like). The amount of the organic solvent used is preferably set to an amount of 0.1 to 50% by mass with respect to the total amount of the reaction solution.

[0117] In this manner, a polymeric solution in which the polyamic acid [P] is dissolved is obtained. The polymeric solution can be directly used for the production of the liquid crystal alignment agent, or the polyamic acid [P] contained in the polymeric solution can be separated and then used for the production of the liquid crystal alignment agent.

[0118] • Polyamic acid ester

[0119] In the case where the polymer [P] is a polyamic acid ester (hereinafter also referred to as "polyamic acid ester [P]"), the polyamic acid ester can be obtained, for example, by a method in which [I] the polyamic acid [P] is reacted with an esterification agent; [II] the compound [A] is reacted with a tetracarboxylic acid diester and a diamine compound, or the compound [A] is reacted after polymerization of the tetracarboxylic acid diester and the diamine compound; or [III] the compound [A] is reacted with a tetracarboxylic acid diester dihalide and a diamine compound, or the compound [A] is reacted after polymerization of the tetracarboxylic acid diester dihalide and the diamine compound. The polyamic acid ester [P] can have only an amic acid ester structure, or can be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist. A reaction solution in which the polyamic acid ester [P] is dissolved can be directly used for the production of the liquid crystal alignment agent, or the polyamic acid ester [P] contained in the reaction solution can be separated and then used for the production of the liquid crystal alignment agent.

[0120] • Polyimide

[0121] In the case where the polymeric body [P] is a polyimide, the polyimide (hereinafter also referred to as "polyimide [P]") can be obtained, for example, by subjecting the polyamic acid [P] synthesized in the above-described manner to dehydration ring closure and imidization. The polyimide [P] can be a fully imidized product in which all of the amic acid structures of the polyamic acid [P] as a precursor thereof are subjected to dehydration ring closure, or can be a partially imidized product in which only a part of the amic acid structures are subjected to dehydration ring closure, and the amic acid structures and imide ring structures coexist. The polyimide [P] preferably has an imidization rate of 20% to 99%, and more preferably has an imidization rate of 30% to 90%. Furthermore, 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 amic acid structures and the number of imide ring structures of the polyimide. Here, a part of the imide ring can be an isoimide ring.

[0122] 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. In the method, as the dehydrating agent, an acid anhydride such as acetic anhydride, propionic anhydride, trifluoroacetic anhydride, or the like can be used. The amount of the dehydrating agent used is preferably 0.01 mol to 20 mol with respect to 1 mol of the amic acid structure of the polyamic acid [P]. As the dehydration ring closure catalyst, a tertiary amine such as pyridine, collidine, lutidine, triethylamine, or the like can be used. The amount of the dehydration ring closure catalyst used is preferably 0.01 mol to 10 mol with respect to 1 mol of the dehydrating agent used. As the organic solvent used in the dehydration ring closure reaction, the organic solvents exemplified as the organic solvents used in the synthesis of the polyamic acid [P] can be used. The reaction temperature of the dehydration ring closure reaction is preferably 0°C to 180°C. The reaction time is preferably 1.0 hour to 120 hours. Furthermore, the reaction solution containing the polyimide [P] can be directly supplied to the preparation of the liquid crystal alignment agent, or can be supplied to the preparation of the liquid crystal alignment agent after the polyimide [P] is separated.

[0123] Regarding the solution viscosity of the polymeric body [P], when a solution having a concentration of 10% by mass is prepared, the solution viscosity is preferably 10 mPa-s to 800 mPa-s, and more preferably 15 mPa-s to 500 mPa-s. Furthermore, the solution viscosity (mPa-s) is a value measured at 25°C using an E-type rotational viscometer for a polymeric body solution having a concentration of 10% by mass prepared using a good solvent (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, or the like) for the polymeric body [P].

[0124] The weight average molecular weight (Mw) of the polymer [P] measured by gel permeation chromatography (GPC) is preferably 1,000 to 500,000, more preferably 2,000 to 300,000, in terms of polystyrene. In addition, the molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by GPC is preferably 7 or less, more preferably 5 or less. Furthermore, in the production of the liquid crystal alignment agent, one kind of the polymer [P] can be used alone, or two or more kinds of the polymer [P] can be used in combination.

[0125] <Other components>

[0126] The liquid crystal alignment agent can contain, in addition to the polymer [P], a component (hereinafter also referred to as "other component") other than the polymer [P], as necessary.

[0127] • Polymer [Q]

[0128] The liquid crystal alignment agent of the present disclosure can also contain, as the polymer component, a polymer (hereinafter also referred to as polymer [Q]) having no partial structure (A). The main skeleton of the polymer [Q] is not particularly limited. As the polymer [Q], 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, or the like can be exemplified. Among these, from the viewpoint of obtaining a liquid crystal element with high reliability, the polymer [Q] 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. 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, or the like can be exemplified.

[0129] In the case where the polymer [Q] is contained in the liquid crystal alignment agent, the content ratio of the polymer [Q] with respect to the total amount of the polymer [P] and the polymer [Q] is preferably 1% by mass or more, more preferably 2% by mass or more. In addition, the content ratio of the polymer [Q] with respect to the total amount of the polymer [P] and the polymer [Q] is preferably 95% by mass or less, more preferably 90% by mass or less. One kind of the polymer [Q] can be used alone, or two or more kinds of the polymer [Q] can be used in combination.

[0130] • Cross-linking agent

[0131] The liquid crystal alignment agent of the present disclosure can also contain a crosslinking agent. As the crosslinking agent, a compound having a functional group capable of reacting with an amino group (hereinafter also referred to as "crosslinkable group") can be preferably used. As a preferable specific example of the crosslinking agent contained in the liquid crystal alignment agent of the present disclosure, a compound (hereinafter also referred to as "compound [B]") containing, as the crosslinkable group, at least one group selected from the group consisting of a group having a polymerizable carbon-carbon bond, a cyclic ether group, a cyclic sulfide group, an isocyanate group, a protected isocyanate group, a hydroxymethyl group, a protected hydroxymethyl group, a cyclic carbonate group, a group "-CR 20 =CR 21 -R 22 - " (wherein R 20 is a monovalent group which is detached by reaction with an amino group; R 21 is a hydrogen atom or an alkyl group, and R 22 is an electron-withdrawing group), a silanol group, and an alkoxysilane group.

[0132] Among the crosslinkable groups, as the group having a polymerizable carbon-carbon bond, a (meth)acryloyl group, a maleimide group, an alkenyl group, a vinylphenyl group, a vinyl ether group, a 3-methylene tetrahydrofuran-2(3H)-one-5-yl group, and the like can be exemplified. In the group "-CR 20 =CR 21 -R 22 - ", as the monovalent organic group represented by R 20 , an alkoxy group having a carbon number of 1 to 5, a pyrrolidin-1-yl group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like) can be exemplified. As the electron-withdrawing group of R 22 , a carbonyl group, a sulfonyl group, and the like can be exemplified.

[0133] From the viewpoint of well-balanced improvement in liquid crystal alignment properties, voltage holding ratio, and film strength, and suppression of reduction in reworkability, the number of crosslinkable groups possessed by the compound [B] in one molecule is preferably 2 to 12, more preferably 2 to 10. From the aspect of storage stability, the molecular weight of the compound [B] is preferably 3,000 or less, more preferably 2,000 or less, and further preferably 1,000 or less.

[0134] As specific examples of the compound [B], a compound having a polymerizable carbon-carbon bond can be exemplified by, for example, ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, a compound represented by the following formula (b-1) to formula (b-6), respectively, and the like;

[0135] Compounds having a cyclic (thio)ether group, for example, can include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, triglycidyl isocyanurate, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-phenylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N-diglycidyl-benzylamine, N,N-diglycidyl-aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine, and the like;

[0136] Compounds having an isocyanate group or a protected isocyanate group, for example, can include compounds represented by the following formulae (b-7) to (b-11), and the like;

[0137] Compounds having a hydroxymethyl group or a protected hydroxymethyl group, for example, can include compounds represented by the following formulae (b-12) to (b-17), and the like;

[0138] Compounds having a cyclic carbonate group, for example, can include compounds represented by the following formulae (b-18) and (b-19), and the like;

[0139] Compounds having a group "-CR 20 =CR 21 -R 22 -", for example, can include compounds represented by the following formulae (b-20) to (b-26), and the like;

[0140] Compounds having an alkoxysilane group or a silanol group, for example, can include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, vinyltriethoxysilane, trimethoxysilylpropyl succinic anhydride, and the like.

[0141] [Chemical Formula 14]

[0142]

[0143] [Chemical Formula 15]

[0144]

[0145] [Chemical Formula 16]

[0146]

[0147] (In formula (b-7) and formula (b-8), R 23 is a thermally detachable group.

[0148] [Chemical 17]

[0149]

[0150] (In formula (b-16), Ac is an acetyl group.

[0151] [Chemical 18]

[0152]

[0153] [Chemical 19]

[0154]

[0155] When the liquid crystal alignment agent of the present disclosure contains a crosslinking agent, the content of the crosslinking agent is preferably 0.02 parts by mass or greater relative to 100 parts by mass of the total amount of the polymeric component contained in the liquid crystal alignment agent from the viewpoint of improving the close contact of the liquid crystal alignment film and from the viewpoint of obtaining a liquid crystal element excellent in liquid crystal alignment properties and electric properties. The content of the crosslinking agent is more preferably 0.5 parts by mass or greater and further preferably 1 part by mass or greater relative to 100 parts by mass of the total amount of the polymeric component. In addition, the content of the crosslinking agent is preferably 20 parts by mass or less and more preferably 15 parts by mass or less relative to 100 parts by mass of the total amount of the polymeric component from the viewpoint of obtaining a liquid crystal element satisfying liquid crystal alignment properties, electric properties, storage stability, and reworkability. As the crosslinking agent, one kind alone can be used or two or more kinds can be used in combination.

[0156] • Solvent

[0157] The liquid crystal alignment agent of the present disclosure is preferably produced in the form of a liquid composition in which the polymeric [P] and other components, if used, are dispersed or dissolved in an appropriate solvent.

[0158] As the solvent, an organic solvent is preferably used. As specific examples thereof, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, phenol, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, 1-hexanol, 2-hexanol, propane-1,2-diol, 3-methoxy-1-butanol, ethylene glycol monomethyl ether, methyl lactate, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, ethyl propionate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, 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, propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentane, cyclohexane, and the like can be listed. One kind or two or more kinds thereof can be used alone.

[0159] As other components contained in the liquid crystal alignment agent, in addition to the above, for example, an antioxidant, a metal chelate compound, a hardening accelerator, a surfactant, a filler, a dispersant, a photo sensitizer, and the like can be listed. The blending ratio of the other components can be appropriately selected depending on each compound within a range not impairing the effects of the present disclosure.

[0160] The solid component concentration in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent of the liquid crystal alignment agent to 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%. If the solid component concentration is 1 mass% or more, the film thickness of the coating film can be sufficiently ensured, and a liquid crystal alignment film showing more excellent liquid crystal alignment properties can be obtained, which is preferable in this respect. On the other hand, if the solid component concentration is 10 mass% or less, the coating film can be made to an appropriate thickness, a liquid crystal alignment film showing excellent liquid crystal alignment properties can be easily obtained, and in addition, the viscosity of the liquid crystal alignment agent becomes moderate, and there is a tendency that the coatability can be made excellent.

[0161] Liquid crystal alignment film and liquid crystal element

[0162] The liquid crystal alignment film disclosed herein can be manufactured using a liquid crystal alignment agent prepared as described. Furthermore, the liquid crystal element disclosed herein includes a liquid crystal alignment film formed using the liquid crystal alignment agent described herein. The driving method of the liquid crystal in the liquid crystal element is not particularly limited, and can be applied to various modes such as twisted nematic (TN) type, super twisted nematic (STN) type, vertical alignment (VA) type (including vertical alignment-multi-domain vertical alignment (VA-MVA) type, vertical alignment-patterned vertical alignment (VA-PVA) type, in-plane switching (IPS) type, fringe field switching (FFS) type, optically compensated bend (OCB) type, and polymer-sustained alignment (PSA). Liquid crystal elements can be manufactured, for example, using a method comprising steps 1 to 3 below. Step 1 uses different substrates depending on the required operating mode. Steps 2 and 3 are common to all operating modes.

[0163] <Step 1: Coating Formation>

[0164] First, a liquid crystal alignment agent is coated onto a substrate, preferably by heating the coated surface to form a coating film on the substrate. Examples of substrates that can be used include: float glass, soda glass, etc.; and transparent substrates containing plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefins). When manufacturing TN, STN, VA, or PSA type liquid crystal elements, two substrates with patterned transparent conductive films are used. Conversely, when manufacturing IPS or FFS type liquid crystal elements, a substrate with patterned comb-shaped electrodes and a substrate without electrodes facing each other are used. As transparent conductive films, NESA films (a registered trademark of PPG Industries, Inc.) containing tin oxide (SnO2) and indium tin oxide (ITO) films containing indium oxide-tin oxide (In2O3-SnO2) can be used.

[0165] There are no particular limitations on the method for applying liquid crystal alignment agent to the substrate. The application of liquid crystal alignment agent to the substrate can be performed by methods such as spin coating, printing (e.g., offset printing, flexographic printing), inkjet printing, slot coating, bar coating, extrusion die coating, direct gravure coating, chamber doctor coater coating, offset gravure coating, impregnation coating, and MB coating.

[0166] After coating the liquid crystal alignment agent, preheating (pre-baking) is preferably performed to prevent sagging of the coated liquid crystal alignment agent. The pre-baking temperature is preferably 30°C to 200°C, and the pre-baking time is preferably 0.25 minutes to 10 minutes. Afterward, the solvent is completely removed, and a calcination (post-baking) process is performed as needed for the purpose of thermally imidizing the amyl acid structure present in the polymer. The calcination temperature (post-baking temperature) at this time is preferably 80°C to 280°C, more preferably 80°C to 250°C. The post-baking time is preferably 5 minutes to 200 minutes. The thickness of the formed film is preferably 0.001 μm to 1 μm.

[0167] <Step 2: Orientation Treatment>

[0168] In manufacturing TN, STN, IPS, or FFS type liquid crystal elements, the coating film formed in step 1 undergoes an alignment process to impart liquid crystal alignment capability. This imparts the alignment capability of the liquid crystal molecules to the coating film, forming a liquid crystal alignment film. Preferably, the alignment process involves rubbing the surface of the coating film formed on the substrate with cotton or nylon, or photoalignment by irradiating the coating film with light to impart liquid crystal alignment capability. In manufacturing vertically aligned liquid crystal elements, the coating film formed in step 1 can be used directly as a liquid crystal alignment film; however, to further improve the liquid crystal alignment capability, an alignment process can also be performed on the coating film. The liquid crystal alignment film preferred for vertically aligned liquid crystal elements can also preferably be used for PSA type liquid crystal elements.

[0169] Light irradiation for photoorientation can be performed by methods such as: irradiating a coating after a post-baking process; irradiating a coating after a pre-baking process and before a post-baking process; or irradiating a coating during heating in at least one of the pre-baking and post-baking processes. As the radiation irradiating the coating, ultraviolet light and visible light with wavelengths from 150 nm to 800 nm can be used, for example. Ultraviolet light with wavelengths from 200 nm to 400 nm is preferred. When the radiation is polarized, it can be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, irradiation can be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these directions. For unpolarized radiation, the irradiation direction is set to an oblique direction.

[0170] Examples of light sources used include: low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, and excimer lasers. The preferred radiation dose is 200 J / m². 2 ~30,000J / m 2 More preferably 500 J / m 2 ~10,000J / m 2 After light irradiation to impart orientation capability, the substrate surface may be cleaned with, for example, water, organic solvents (e.g., methanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.), or a mixture thereof, or the substrate may be heated.

[0171] <Step 3: Construction of the Liquid Crystal Cell>

[0172] Two substrates with liquid crystal alignment films formed as described above are prepared, and liquid crystal is disposed between the two substrates arranged facing each other, thereby manufacturing a liquid crystal cell. In manufacturing the liquid crystal cell, methods such as: arranging the two substrates facing each other with the liquid crystal alignment films facing each other and a gap between them; bonding the peripheries of the two substrates together using a sealant; injecting liquid crystal into the cell gap surrounded by the substrate surfaces and the sealant and sealing the injection hole; or using a one-drop fill (ODF) method. As a sealant, for example, epoxy resin containing a hardener and alumina spheres as spacers can be used. As a liquid crystal, nematic liquid crystals and dish liquid crystals can be used, with nematic liquid crystals being preferred.

[0173] In PSA mode, the following process is performed: a polymeric compound (e.g., a polyfunctional (meth)acrylate compound, etc.) is filled into the cell gaps along with liquid crystal, and after the liquid crystal cells are constructed, the liquid crystal cells are irradiated with light while a voltage is applied between the conductive films of a pair of substrates. When manufacturing PSA-type liquid crystal elements, the proportion of the polymeric compound used relative to 100 parts by mass of the total liquid crystal is, for example, 0.01 to 3 parts by mass, preferably 0.05 to 1 part by mass.

[0174] In the manufacture of a liquid crystal display device, a polarizing plate is then attached to the outer surface of the liquid crystal cell. Examples of polarizing plates include polarizing plates made by sandwiching a polarizing film called an "H-film" with a cellulose acetate protective film, or polarizing plates containing an H-film itself, wherein the "H-film" is formed by absorbing iodine while extending and oriented polyvinyl alcohol.

[0175] The liquid crystal element disclosed herein can be effectively applied to a variety of uses. Specifically, it can be used, for example, in clocks, portable game consoles, word processors, notebook personal computers, car navigation systems, camcorders, personal digital assistants (PDAs), digital cameras, mobile phones, smartphones, various monitors, LCD TVs, information displays, and other display devices or dimming devices, retardation films, etc.

[0176] [Example]

[0177] The following describes the implementation methods in more detail based on the embodiments, but the invention is not to be construed as limited by the following embodiments.

[0178] In the following examples, the imidization rate of the polyimide in the polymer solution, as well as the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the styrene-maleimide copolymer, were determined using the following methods. The required amounts of the starting materials and polymers used in the following examples were ensured by repeating the synthesis at the scale shown in the following synthetic examples as needed.

[0179] [Imidification rate of polyimide]

[0180] A solution of polyimide was added to pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. It was then dissolved in dimethyl sulfoxide (DMSO), and 1H NMR was performed at room temperature using tetramethylsilane as a reference. 1 H-nuclear magnetic resonance,1 H-NMR) determination. Based on the obtained 1 The imidization rate [%) was determined using the following formula (1) from the H-NMR spectrum.

[0181] Imidification rate [%] = (1-(A) 1 / (A 2 ×α)))×100…(1)

[0182] (In equation (1), A 1 It is the peak area of ​​protons originating from NH groups that appears near a chemical shift of 10 ppm, A 2 It is the peak area derived from other protons, and α is the ratio of the number of other protons to the number of 1 proton of the NH group in the polymer precursor (polyamic acid).

[0183] [Weight-average molecular weight (Mw) and number-average molecular weight (Mn)]

[0184] Mw and Mn are polystyrene conversion values ​​determined by GPC under the following conditions.

[0185] Tube column: Manufactured by Tosoh (stock), TSKgelGRCXLII

[0186] Solvent: Tetrahydrofuran

[0187] Temperature: 40℃

[0188] Pressure: 68 kgf / cm 2

[0189] The abbreviation for the compound is as follows. Furthermore, in the following, the compound represented by formula (X) may sometimes be simply referred to as "compound (X)".

[0190] (Tetracarboxylic acid dianhydride)

[0191] [Chemistry 20]

[0192]

[0193] (Diamine compounds)

[0194] [Chemistry 21]

[0195]

[0196] [Chemistry 22]

[0197]

[0198] (Capped amine)

[0199] [Chemistry 23]

[0200]

[0201] (Siloxane monomers and reactive compounds)

[0202] [Chemistry 24]

[0203]

[0204] (Styrene-maleimide copolymer monomers)

[0205] [Chemistry 25]

[0206]

[0207] (Cross-linking agent)

[0208] [Chemistry 26]

[0209]

[0210] [Chemistry 27]

[0211]

[0212] (In formula (AD-5), R is a tert-butoxycarbonyl group or a group derived from methyl ethyl ketone oxime (*-ON=C(CH3)(C2H5)).)

[0213] [Chemistry 28]

[0214]

[0215] <Synthesis of Polymers>

[0216] 1. Synthesis of polyamic acid

[0217] [Synthesis example 1]

[0218] 70 moles of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 30 moles of 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 60 moles of 1,2-bis(4-aminophenoxy)ethane as a diamine compound, and 40 moles of compound (DB-13) were dissolved in N-methyl-2-pyrrolidone (NMP) and reacted at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamic acid (designated as polymer (PA-1)).

[0219] [Synthesis Example 2, Synthesis Example 4 to Synthesis Example 13]

[0220] The types and amounts of the tetracarboxylic dianhydride and diamine compound used were changed as described in Tables 1 and 2. Otherwise, the same procedures as in Synthesis Example 1 were performed to obtain a solution containing polyamic acid (polymers (PA-2) to (PA-5), and polymers (PA-16) to (PA-23)). Furthermore, in Synthesis Examples 4 and 5, the capped amine was dissolved together with the tetracarboxylic dianhydride and diamine compound in NMP for reaction.

[0221] [Synthesis example 3]

[0222] The types and amounts of the tetracarboxylic dianhydride and diamine compounds used were changed as described in Table 1. Otherwise, polymerization was carried out in the same manner as in Synthesis Example 1 to obtain a polymer solution containing polyamic acid. Subsequently, a capped amine (MA-3) was added to the obtained polymer solution, and the reaction was carried out at room temperature for 3 hours to obtain a solution containing polymer (PA-3).

[0223] [Table 1]

[0224]

[0225] [Table 2]

[0226]

[0227] 2. Synthesis of polyimide

[0228] [Synthesis Example 14]

[0229] Polymerization was carried out in the same manner as in Synthesis Example 1 to obtain a solution containing 15% by mass of polymer (PA-1). Subsequently, NMP was added to the obtained polymer solution to prepare a solution with a polyamic acid concentration of 10% by mass. Pyridine and acetic anhydride were then added, and a dehydration and ring-closure reaction was carried out at 60°C for 4 hours. After the dehydration and ring-closure reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by mass of polyimide with an imidization rate of approximately 80% (designated as polymer (PI-1)).

[0230] [Synthesis Example 15 to Synthesis Example 21, Synthesis Example 23 to Synthesis Example 26]

[0231] The types and amounts of the tetracarboxylic dianhydride and diamine compound used were changed as described in Tables 3 and 4. Otherwise, the same procedures as in Synthesis Example 14 were performed to obtain a solution containing polyimide (polymers (PI-2) to (PI-8), (PI-10), and (PI-11)). Furthermore, in Synthesis Examples 15, 17 to 21, 24, and 25, the capped amine was dissolved together with the tetracarboxylic dianhydride and diamine compound in NMP for reaction.

[0232] [Synthesis Example 22]

[0233] The types and amounts of the tetracarboxylic dianhydride and diamine compounds used were changed as described in Table 3. Otherwise, polymerization was carried out in the same manner as in Synthesis Example 1 to obtain a polymer solution containing polyamic acid. Subsequently, a terminal amine (MA-1) was added to the obtained polymer solution, and the reaction was carried out at room temperature for 3 hours. Afterward, the polyamic acid was imidized in the same manner as in Synthesis Example 14 to obtain a solution containing polymer (PI-9) as a polyimide.

[0234] [Table 3]

[0235]

[0236] [Table 4]

[0237]

[0238] 3. Synthesis of Polyorganosiloxanes

[0239] [Synthesis Example 27]

[0240] 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (the compound represented by formula (S-1)) , 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine were placed in a 1000 mL three-necked flask and mixed at room temperature. Then, 100 g of deionized water was added dropwise through a dropping funnel over 30 minutes, and the mixture was stirred under reflux at 80 °C for 6 hours. After the reaction was complete, the organic layer was removed and washed with a 0.2% ammonium nitrate aqueous solution until the water was neutral. The solvent and water were then removed by distillation under reduced pressure. A suitable amount of methyl isobutyl ketone was added to obtain a 50% solution of an epoxy-containing polyorganosiloxane polymer (ESSQ-1).

[0241] In a 500 mL three-necked flask, 3.10 g of compound (c-1) (containing 20 mol% epoxy groups relative to polymer (ESSQ-1), 3.24 g of compound (c-2) (containing 10 mol% epoxy groups relative to polymer (ESSQ-1), 1.00 g of tetrabutylammonium bromide, 20.0 g of a solution containing polymer (ESSQ-1), and 290.0 g of methyl isobutyl ketone were added and stirred at 90 °C for 18 hours. After cooling to room temperature, the mixture was repeatedly separated and washed 10 times with distilled water. Subsequently, the organic layer was recovered, and the solution was concentrated twice using a rotary evaporator and diluted with NMP. The solution was then adjusted with NMP to a solids concentration of 10% by mass to obtain an NMP solution of the polyorganosiloxane (referred to as polymer (PSQ-1)).

[0242] 4. Synthesis of styrene-maleimide copolymers

[0243] [Synthesis Example 28]

[0244] Under nitrogen atmosphere, 10 moles of compound (M-1), 10 moles of compound (M-2), 30 moles of compound (M-3), 10 moles of compound (M-4), 20 moles of compound (M-5), and 20 moles of compound (M-6) as monomers, 2 moles of 2,2'-azobis(2,4-dimethylpentanones) as a free radical polymerization initiator, and 50 mL of tetrahydrofuran as a solvent were added to a 100 mL two-necked flask. Polymerization was carried out at 70 °C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and dried under vacuum at room temperature for 8 hours to obtain a styrene-maleimide copolymer (designated as polymer (MI-1)). For polymer (MI-1), the weight-average molecular weight (Mw) determined by GPC and converted to polystyrene was 92,700, and the molecular weight distribution (Mw / Mn) was 4.78.

[0245] <Preparation and Evaluation of Liquid Crystal Alignment Agents>

[0246] [Example 1: Frictional FFS Type Liquid Crystal Display Element]

[0247] 1. Preparation of liquid crystal alignment agent

[0248] In a solution of the polymer (PI-4) obtained in Synthesis Example 17, 5 parts by mass of a compound (AD-1) as a crosslinking agent were added relative to 100 parts by mass of the polymer (solid component). The solution was diluted with NMP and butyl cellolsolve (BC) to prepare a solution with a solvent composition of NMP / BC = 80 / 20 (mass ratio) and a solid component concentration of 3.5% by mass. The solution was filtered using a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-1).

[0249] 2. Manufacturing of FFS-type liquid crystal cells using the triboelectric method

[0250] A glass substrate (designated as the first substrate) with a flat plate electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) stacked sequentially on one side, and a glass substrate without electrodes (designated as the second substrate) are prepared. A liquid crystal alignment agent (AL-1) is then coated onto the electrode forming surface of the first substrate and one side of the second substrate using a rotator, and heated (pre-baked) for 3 minutes using a heating plate at 110°C. Subsequently, it is dried (post-baked) for 30 minutes in a 230°C oven where nitrogen replacement has been performed, forming a coating with an average film thickness of 0.08 μm. The coating surface is then rubbed using a friction machine with rollers wound with rayon cloth, at a roller speed of 1000 rpm, a platform movement speed of 3 cm / sec, and a bristle indentation length of 0.3 mm. Afterward, it is ultrasonically cleaned in ultrapure water for 1 minute, and then dried in a 100°C clean oven for 10 minutes, thereby obtaining a pair of substrates with a liquid crystal alignment film.

[0251] Next, for a pair of substrates with a liquid crystal alignment film, a liquid crystal injection port is left at the edge of the surface where the liquid crystal alignment film is formed, and an epoxy resin adhesive containing alumina spheres with a diameter of 3.5 μm is applied by screen printing. The substrates are then overlapped and pressed together, and the adhesive is thermosetting at 150°C for 1 hour. Then, negative liquid crystal (manufactured by Merck, MLC-6608) is filled into the gap between the two substrates through the liquid crystal injection port, and the liquid crystal injection port is then sealed with an epoxy adhesive. Furthermore, to remove the flow alignment during liquid crystal injection, it is heated at 120°C and then slowly cooled to room temperature to manufacture a liquid crystal cell. In addition, when overlapping the pair of substrates, the rubbing method of each substrate is made antiparallel.

[0252] 3. Evaluation of liquid crystal orientation

[0253] The liquid crystal cell manufactured in step 2. is subjected to a temperature of 27,000 cd / m². 2The liquid crystal cells were left to stand on a high-brightness backlight for 500 hours, and the liquid crystal alignment was evaluated based on the rate of change in retardation before and after backlight illumination. First, for the liquid crystal cells manufactured in step 2, the retardation was measured using an Axoscan instrument manufactured by Optoscience, and the rate of change in retardation α before and after backlight illumination was calculated using the following formula (z-1). The smaller the rate of change α, the better the liquid crystal alignment. A rate of change α less than 1% was defined as "good (○)", 1% or more but less than 2% was defined as "acceptable (△)", and 2% or more was defined as "poor (×)".

[0254] α=Δθ / θ1…(z-1)

[0255] (In equation (z-1), Δθ represents the delay difference before and after irradiation, and θ1 represents the delay value before irradiation.)

[0256] As a result, the liquid crystal orientation of the embodiment was evaluated as "good (○)".

[0257] 4. Evaluation of AC image retention characteristics

[0258] For the liquid crystal cell manufactured in 2, after driving it with an AC voltage of 10V for 72 hours, the minimum relative transmittance (%) represented by the following formula (2) is measured using a device in which a polarizer and an analyzer are arranged between the light source and the light quantity detector.

[0259] Minimum relative transmittance (%) = (β-B0) / (B100-B0)×100…(2)

[0260] In equation (2), B0 is the amount of light transmitted under blank and orthogonal Nicol prisms. B100 is the amount of light transmitted under blank and parallel Nicol prisms. β is the amount of light transmitted when the liquid crystal cell is sandwiched between the polarizer and the analyzer under orthogonal Nicol prisms, which is the minimum amount of light transmitted.

[0261] The black level in the dark state is represented by the minimum relative transmittance of the liquid crystal cell. In an FFS type liquid crystal cell, the smaller the black level in the dark state, the better the contrast. A minimum relative transmittance of less than 0.3% is defined as "Excellent (◎)", 0.3% or more but less than 1.3% as "Good (○)", 1.3% or more but less than 2.0% as "Acceptable (△)", and 2.0% or more as "Poor (×)". The result, in the described embodiment, is an evaluation of "Excellent (◎)".

[0262] 5. Evaluation of initial voltage holding ratio (VHR)

[0263] After the liquid crystal cell manufactured in step 2 was placed in an oven at 60°C, the voltage holding rate (VHR) was measured using a VHR-1 measuring device manufactured by Toyo Technica Co., Ltd., at 1V and 1670ms. As an evaluation criterion, a VHR higher than 80% was designated as "Good (○)", a VHR between 60% and 80% was designated as "Acceptable (△)", and a VHR less than 60% was designated as "Poor (×)". As a result, the initial VHR of the embodiment was evaluated as "Good (○)".

[0264] 6. Evaluation of membrane strength (friction resistance)

[0265] The liquid crystal alignment agent (AL-1) prepared in step 1 was coated onto a glass substrate using a rotator and heated (pre-baked) for 3 minutes using a heating plate at 110°C. Subsequently, it was dried (post-baked) for 30 minutes in a 230°C oven where nitrogen replacement had been performed, resulting in a coating with an average thickness of 0.08 μm. The haze value of the coating was measured using a haze meter. Next, the coating was subjected to five rubbing treatments using a rubbing machine with rollers wound with cotton cloth, at a roller speed of 1000 rpm, a platform movement speed of 3 cm / sec, and a bristle indentation length of 0.3 mm. The haze value of the liquid crystal alignment film was then measured using a haze meter, and the difference between the haze value and the haze value before the rubbing treatment (haze change value) was calculated. With the haze value of the film before the rubbing treatment set as Hz1 (%) and the haze value of the film after the rubbing treatment set as Hz2 (%), the haze change value is expressed by the following formula (z-2).

[0266] Haze change (%) = Hz2 - Hz1...(z-2)

[0267] A haze change value of less than 0.5 for the liquid crystal alignment film is evaluated as "Excellent (◎)", 0.5 or higher but less than 0.8 is evaluated as "Good (○)", 0.8 or higher but less than 1.0 is evaluated as "Acceptable (△)", and 1.0 or higher is evaluated as "Poor (×)". If the haze change value is less than 1.0, the film strength is considered sufficiently high and the friction resistance is high, meaning the film has good mechanical properties. As a result, the film strength in the described embodiment is evaluated as "Excellent (◎)".

[0268] 7. Evaluation of membrane adhesion

[0269] The liquid crystal alignment agent (AL-1) prepared in step 1) was coated onto a glass substrate using a spinner. After pre-baking at 80°C for 1 minute, it was heated (post-baked) in a 230°C oven with nitrogen purging for 1 hour, thereby forming a coating with an average thickness of 0.1 μm. Two coated glass substrates were fabricated by repeating the same operation. On the coating of one coated glass substrate, an ODF sealant (S-WB42 manufactured by Sekisui Chemicals) was applied in a diameter of 4.8 mm to 5.2 mm, and the two substrates were bonded together with the ODF sealant in contact with the coating. Subsequently, the substrates were irradiated with a metal halide lamp at 30,000 J / m². 2 After being exposed to light (converted to 365nm), the film was heated in an oven at 120°C for 1 hour. Subsequently, the adhesion strength was measured using a tensile compression testing machine (model: SDWS-0201-100SL) from Imada Manufacturing Co., Ltd. to evaluate the film's adhesion.

[0270] In the evaluation, the bonding strength was set at 300 gf / mm. 2 The above conditions are set as "Excellent (◎)" for tightness, and 200gf / mm 2 Above and below 300gf / mm 2 The condition is set as "Good (○)" for tightness, and 100gf / mm 2 Above and below 200gf / mm 2 The condition is set as "acceptable (△)" for tightness, and less than 100gf / mm 2 The condition is set as "poor (×)" in terms of contact tightness. As a result, in the described embodiment, the contact tightness is rated as "excellent (◎)".

[0271] 8. Evaluation of reprocessability

[0272] On a transparent conductive film containing an ITO film, prepared as described above, was applied using a spin coater to one side of a 1 mm thick glass substrate. The substrate was then pre-baked at 100°C for 90 seconds using a heating plate to form a coating approximately 0.08 μm thick. This process was repeated to fabricate two substrates with the coating. The two substrates were then stored in a dark chamber at 25°C under nitrogen atmosphere. After 12 hours and 48 hours of storage, one substrate was removed and immersed in a beaker containing NMP at 40°C for 2 minutes. The substrates were then rinsed several times with ultrapure water, and surface water droplets were removed using an air blower. The substrates were observed using an optical microscope to check for coating residue, thereby evaluating the ease of peeling the liquid crystal alignment film from the substrate (reprocessability).

[0273] Regarding the evaluation, a substrate that was removed even 48 hours after the start of storage and showed no coating residue after NMP immersion was defined as having "good" reprocessability (○). A substrate with coating residue observed after 48 hours but not after 12 hours was defined as having "acceptable" reprocessability (△). A substrate with coating residue observed after 12 hours was defined as having "poor" reprocessability (×). As a result, in the described embodiment, the reprocessability was "good" (○).

[0274] [Examples 2 to 20 and Comparative Examples 1 to 4]

[0275] The composition of the liquid crystal alignment agent was changed as shown in Table 5, except that the liquid crystal alignment agent was prepared in the same manner as in Example 1. Furthermore, using the obtained liquid crystal alignment agent, FFS-type liquid crystal cells were manufactured by the rubbing method in the same manner as in Example 1, and various evaluations were performed. These results are shown in Table 5. In addition, in Examples 3-5, 7, 8, 12, 14, 19, and 20, two or three polymers were used as polymer components. In Table 5, the numerical values ​​of the alignment agent composition represent the mixing ratio (parts by mass) of each compound relative to 100 parts by mass of the total amount of polymer components used in the preparation of the liquid crystal alignment agent (the same applies to Tables 6 and 7).

[0276] [Table 5]

[0277]

[0278] In Table 5, the abbreviations for crosslinking agents are as follows.

[0279] AD-6: Product name "TRIXENE 7982", manufactured by Baxenden Company.

[0280] As shown in Table 5, Examples 1 to 20 using liquid crystal alignment agents containing polymer [P] achieved a good balance in terms of liquid crystal alignment, image retention characteristics, initial VHR, film strength (friction resistance), film adhesion, and reprocessability compared to Comparative Examples 1 to 4 using liquid crystal alignment agents without polymer [P].

[0281] [Example 21: Optical FFS type liquid crystal display element]

[0282] 1. Preparation of liquid crystal alignment agent

[0283] In a solution containing the polymer (PI-6) obtained in Synthesis Example 19, 3 parts by mass of a compound (AD-3) as a crosslinking agent were added relative to 100 parts by mass of the polymer (solid component), and the solution was diluted with NMP and BC to prepare a solution with a solvent composition of NMP / BC = 80 / 20 (mass ratio) and a solid component concentration of 3.5% by mass. The solution was filtered using a filter with a pore size of 0.2 μm, thereby preparing a liquid crystal alignment agent (AL-21).

[0284] 2. Manufacturing of FFS-type liquid crystal display elements using photo-alignment method

[0285] Prepare a first substrate and a second substrate identical to those in Example 1. Then, using a spinner, apply a liquid crystal alignment agent (AL-21) to the electrode forming surface of the first substrate and one of the substrate surfaces of the second substrate, respectively, and heat (pre-baking) at 80°C for 1 minute. Subsequently, dry (post-baking) for 30 minutes in a 230°C oven where nitrogen replacement was performed inside, forming a coating with an average thickness of 0.1 μm. Irradiate the obtained coating with 1,000 J / m² of ultraviolet light containing linearly polarized 254 nm bright rays from the substrate normal direction using an Hg-Xe lamp. 2 The photo-alignment process is then performed. Furthermore, the irradiation amount is measured using a photometer with a wavelength of 254 nm as the reference. Subsequently, the photo-aligned coating is heat-treated by heating it in a clean oven at 230°C for 30 minutes to form a liquid crystal alignment film.

[0286] Next, for one of the pair of substrates with the liquid crystal alignment film, an epoxy resin adhesive containing alumina spheres with a diameter of 3.5 μm was screen-printed onto the outer edge of the surface with the liquid crystal alignment film. Then, the substrates were overlapped and pressed together with the projection direction of the polarization axis on the substrate surface being antiparallel during light irradiation, and the adhesive was thermosetting at 150°C for 1 hour. Subsequently, negative liquid crystal (manufactured by Merck, MLC-6608) was filled between the pair of substrates through the liquid crystal injection port, and the liquid crystal injection port was sealed using an epoxy adhesive to obtain a liquid crystal cell. Furthermore, to remove the flow alignment during liquid crystal injection, it was heated at 120°C and then slowly cooled to room temperature. Additionally, the post-baked ultraviolet irradiation dose was 100 J / m². 2 ~10,000J / m 2 The series of operations are performed by changing the range of UV exposure, thereby producing three or more liquid crystal cells with different UV exposure amounts, and the liquid crystal cell with the exposure amount (optimal exposure amount) showing the best orientation characteristics is evaluated.

[0287] 3. Evaluation

[0288] Using the liquid crystal alignment agent prepared in section 1 and the liquid crystal cell manufactured in section 2, various evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 6.

[0289] [Examples 22-24 and Comparative Examples 5-7]

[0290] The composition of the liquid crystal alignment agent was changed as shown in Table 6, but otherwise, the liquid crystal alignment agent was prepared in the same manner as in Example 21. Furthermore, using the obtained liquid crystal alignment agent, FFS-type liquid crystal cells were fabricated by photoalignment in the same manner as in Example 21, and various evaluations were performed. These results are shown in Table 6.

[0291] [Table 6]

[0292]

[0293]

[0294] As shown in Table 6, Examples 21 to 24, which used liquid crystal alignment agents containing polymer [P], achieved a balance in liquid crystal alignment, image retention characteristics, initial VHR, film strength, film adhesion, and reprocessability compared to Comparative Examples 5 to 7, which used liquid crystal alignment agents without polymer [P]. This is a good result, similar to the case of manufacturing liquid crystal alignment films using the rubbing method.

[0295] [Example 25: PSA type liquid crystal display element]

[0296] 1. Preparation of liquid crystal alignment agent

[0297] A solution containing 5 parts by mass of polymer (PSQ-1) obtained in Synthesis Example 27 and a solution containing 95 parts by mass of polymer (PI-12) obtained in Synthesis Example 25 were mixed and diluted with NMP and BC to prepare a solution with a solvent composition of NMP / BC = 50 / 50 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered using a filter with a pore size of 0.2 μm to prepare the liquid crystal alignment agent (AL-25).

[0298] 2. Preparation of liquid crystal compositions

[0299] To obtain liquid crystal composition LC1, 5% by mass of a liquid crystal compound represented by formula (L1-1) and 0.3% by mass of a photopolymerizable compound represented by formula (L2-1) were added to 10g of nematic liquid crystal (Merck, MLC-6608) and mixed.

[0300] [Chemistry 29]

[0301]

[0302] 3. Manufacturing of PSA-type liquid crystal cells

[0303] On the transparent electrode surface of a glass substrate with a transparent electrode containing an ITO film, the liquid crystal alignment agent (AL-25) prepared herein is coated using a spinner. After pre-baking on a heating plate at 80°C for 1 minute, the solvent is removed by heating at 200°C for 1 hour in a nitrogen-filled oven, thereby forming a coating film (liquid crystal alignment film) with a thickness of 0.08 μm. The coating film is then rubbed using a friction machine with rollers wound with rayon cloth, at a roller speed of 400 rpm, a platform movement speed of 3 cm / sec, and a bristle indentation length of 0.1 mm. Subsequently, it is ultrasonically cleaned in ultrapure water for 1 minute, followed by drying in a 100°C clean oven for 10 minutes, thereby obtaining a substrate with a liquid crystal alignment film. This operation is repeated to obtain a pair (two pieces) of substrates with liquid crystal alignment films. Furthermore, the rubbing treatment is a weak rubbing treatment performed for the purpose of controlling liquid crystal collapse and achieving alignment separation using a simple method.

[0304] On the outer periphery of the surface of one substrate with a liquid crystal alignment film, an epoxy resin adhesive containing alumina spheres with a diameter of 3.5 μm is screen-printed. The liquid crystal alignment films of a pair of substrates are then overlapped and pressed together, and the adhesive is heat-cured at 150°C for 1 hour. Subsequently, the liquid crystal composition PLC1 is filled into the gap between the liquid crystal injection port and the substrate. The liquid crystal injection port is then sealed with an epoxy adhesive. Furthermore, to remove the flow alignment during liquid crystal injection, the mixture is heated at 150°C for 10 minutes and then slowly cooled to room temperature.

[0305] Subsequently, for the obtained liquid crystal cell, under the condition of liquid crystal driving with an AC 10V of 60Hz applied between the electrodes, an ultraviolet irradiation device using a metal halide lamp as the light source was used to irradiate it with 50,000 J / m 2 The ultraviolet light is irradiated with a specific amount of light. Furthermore, this irradiation amount is measured using a photometer with a wavelength of 365 nm as a reference. This allows for the manufacture of a PSA-type liquid crystal cell.

[0306] 4. Evaluation

[0307] For the liquid crystal cells manufactured in step 3, the liquid crystal alignment, initial VHR, film adhesion, and reprocessability were evaluated using the same method as in Example 1. The evaluation results are shown in Table 7.

[0308] [Examples 26, 27, and Comparative Examples 8 and 9]

[0309] The composition of the liquid crystal alignment agent was changed as shown in Table 7, but the liquid crystal alignment agent was prepared in the same manner as in Example 25. Furthermore, using the obtained liquid crystal alignment agent, a PSA-type liquid crystal cell was manufactured in the same manner as in Example 25, and various evaluations were performed. The evaluation results are shown in Table 7.

[0310] [Table 7]

[0311]

[0312] As shown in Table 7, Examples 25-27, which used liquid crystal alignment agents containing polymer [P], compared with Comparative Examples 8 and 9, which used liquid crystal alignment agents without polymer [P], achieved a balance in liquid crystal alignment, initial VHR, film adhesion, and reprocessability, resulting in good performance similar to that of FFS-type liquid crystal display elements. In particular, the improvement in film adhesion was significant when using polymer [P]. This can be attributed to the increased mechanical strength of the film due to the use of polymer [P].

[0313] Based on the above results, it is clear that liquid crystal alignment agents containing polymer [P] can be used to obtain liquid crystal elements with high voltage retention and low image retention, thereby forming liquid crystal alignment films with high film strength, good reprocessability and adhesion.

Claims

1. A liquid crystal alignment agent comprising a polymer [P] having a polyimide backbone and a partial structure (A) represented by formula (1) or formula (2) at the ends of the backbone. In equation (1), R 1 It is tert-butoxycarbonyl; R 2 It is an alkyl group having 1 to 5 carbon atoms, or a monovalent group having -O- between carbon-carbon bonds of the alkyl group; R 3 and R 4 Each can be independently a hydrogen atom or a methyl group; " represents a bond; In equation (2), R 5 It is tert-butoxycarbonyl; R 6 and R 7 Satisfy either (i) or (ii) below; (i)R 6 It is an alkyl group having 1 to 5 carbon atoms, or a monovalent group having -O- between carbon-carbon bonds of the alkyl group; R 7 It is cyclohexanediol; (ii)R 6 and R 7 R represents 6 and R 7 A ring structure formed together with the bonded nitrogen atoms; said ring structure is a pyrrolidine ring or a piperidine ring; " " " indicates a bond.

2. The liquid crystal alignment agent according to claim 1, wherein, The polymer [P] has structural units at the ends of the main chain derived from the compound represented by the following formula (3). In equation (3), A 1 It is a monovalent base having a partial structure represented by equation (1) or equation (2); R 8 For single bonds, -O-, -S-, -CO-, -COO-, -NR 10 -、-CO-NR 10 -、-NR 10 -CO-O-、-NR 10 -CO-NR 11 - Any methylene group in a divalent chain hydrocarbon group with 1 or more carbon atoms, a divalent alicyclic hydrocarbon group with 3 or more carbon atoms, or a divalent chain hydrocarbon group with 2 or more carbon atoms is replaced with -O-, -S-, -CO-, -COO-, or -NR. 10 -、-CO-NR 10 -、-NR 10 -CO-O- or -NR 10 -CO-NR 11 - The divalent base formed; R 10 and R 11 Each can be independently a hydrogen atom or a monovalent organic group; R 9 It is a single bond or (m+1) valence aromatic ring group; m is 1 or 2; where, in R 9 In the case of a single bond, m is 1, and R 8 It is a single bond or a bond between a hydrocarbon group and a primary amino group in formula (3); when m is 2, multiple R 8 Same or different, multiple A's 1 Same or different.

3. The liquid crystal alignment agent according to claim 1 or 2, wherein, The polymer [P] has structural units derived from alicyclic tetracarboxylic dianhydrides.

4. The liquid crystal alignment agent according to claim 1 or 2, further comprising a compound having at least one group selected from the group consisting of a polymerizable carbon-carbon bond, a cyclic ether group, a cyclic thioether group, an isocyanate group, a protected isocyanate group, a hydroxymethyl group, a protected hydroxymethyl group, a cyclic carbonate group, or a "-CR" group. 20 =CR 21 -R 22 -",in, R 20 It is a monovalent group that is removed through a reaction with an amino group; R 21 It is a hydrogen atom or an alkyl group, R 22 It is an electron-withdrawing group, a silanol group, and an alkoxysilyl group.

5. The liquid crystal alignment agent according to claim 1 or 2, further comprising a polymer that does not have said partial structure (A) at the end of the main chain.

6. A liquid crystal alignment agent comprising a polymer [P], said polymer [P] being a polyimide obtained by polymerizing a monomer comprising at least one acid derivative selected from the group consisting of tetracarboxylic dianhydride and tetracarboxylic acid diester dihalides and a diamine compound in the presence of a monoamine compound having a partial structure (A) represented by formula (1) or formula (2), or by reacting said monomer with said monoamine compound after polymerization. In equation (1), R 1 It is tert-butoxycarbonyl; R 2 It is an alkyl group having 1 to 5 carbon atoms, or a monovalent group having -O- between carbon-carbon bonds of the alkyl group; R 3 and R 4 Each can be independently a hydrogen atom or a methyl group; " represents a bond; In equation (2), R 5 It is tert-butoxycarbonyl; R 6 and R 7 Satisfy either (i) or (ii) below; (i)R 6 It is an alkyl group having 1 to 5 carbon atoms, or a monovalent group having -O- between carbon-carbon bonds of the alkyl group; R 7 It is cyclohexanediol; (ii)R 6 and R 7 R represents 6 and R 7 A ring structure formed together with the bonded nitrogen atoms; said ring structure is a pyrrolidine ring or a piperidine ring; " " " indicates a bond.

7. A liquid crystal alignment film formed using a liquid crystal alignment agent as described in any one of claims 1 to 6.

8. A liquid crystal element comprising the liquid crystal alignment film as described in claim 7.

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