Liquid crystal alignment agent, liquid crystal alignment film and method for manufacturing the same, and liquid crystal element and method for manufacturing the same

Abstract

To provide a liquid crystal alignment agent that can produce a liquid crystal element exhibiting good liquid crystal alignment properties, low charge accumulation, and rapid residual charge relaxation, as well as a liquid crystal alignment film with high strength. [Solution] A polymer (A) containing structural units derived from a monomer having a substructure represented by formula (1), and a group F which is at least one selected from the group consisting of polymerizable carbon-carbon unsaturated bond-containing groups, isocyanate groups, protected isocyanate groups, cyclic carbonate groups, groups having a ketene structure, groups having a meldrum acid structure, cyclic ether groups, cyclic thioether groups, oxazoline groups, protected hydroxyalkylamide groups, protected thiol groups, and protected secondary amino groups. 1 A liquid crystal alignment agent containing a compound (B) having a total of two or more of in one molecule and lacking an aromatic ring. In formula (1), Ar 1 and Ar 2 This is a divalent aromatic ring group, etc. 1 X is a hydrogen atom, etc. 1 is -O- etc. TIFF2026087169000033.tif20169

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, a method for manufacturing the same, and a liquid crystal element and a method for manufacturing the same. [Background technology]

[0002] Liquid crystal elements are widely used in televisions, mobile devices, and various monitors. With this increasing versatility, there is a growing demand for higher quality liquid crystal elements. Improvements are being made to the driving method and element structure, as well as to the liquid crystal alignment film, one of the constituent materials of liquid crystal elements.

[0003] In liquid crystal displays, the accumulation of electric charge within the liquid crystal cell is perceived by the observer as an afterimage (DC afterimage), degrading the display quality of the liquid crystal display. Therefore, one of the required characteristics of the liquid crystal alignment film is low charge accumulation. Possible causes of charge accumulation within the liquid crystal cell include the application of asymmetrical voltages due to AC driving and the absorption of backlight light by the liquid crystal alignment film. DC afterimages are particularly likely to occur in FFS (Fringe Field Switching) type liquid crystal display elements, which have an asymmetrical electrode structure.

[0004] Therefore, various techniques have been proposed to suppress the accumulation of charge within liquid crystal cells and improve the display quality of liquid crystal elements (see, for example, Patent Documents 1 and 2). Patent Document 1 discloses reducing accumulated charge by incorporating a polyamic acid obtained by reacting a diamine compound containing a nitrogen-containing diamine such as N4,N4'-bis(4-aminophenyl)-benzidine with a tetracarboxylic dianhydride into a liquid crystal alignment agent. Patent Document 2 discloses obtaining a liquid crystal alignment film in which accumulated charge is quickly relieved and flicker is less likely to occur during operation by incorporating a polymer obtained from a diamine having a structure in which a carbazole structure and a benzene ring are bonded by an amino group into a liquid crystal alignment agent. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2008-107811 [Patent Document 2] International Publication No. 2018 / 110354 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In recent years, with the increasing resolution of liquid crystal elements, quality requirements have become even more stringent. To meet these requirements, liquid crystal elements are required to have further improvements in liquid crystal alignment and voltage retention characteristics. Furthermore, considering the application of the rubbing method, improvements in liquid crystal alignment and voltage retention, and suppression of yield reduction, liquid crystal alignment films formed using liquid crystal alignment agents must have sufficiently high strength. However, it is difficult to balance various characteristics such as liquid crystal alignment and film strength while reducing the occurrence of afterimages and flicker, and there is still room for further improvement in liquid crystal alignment agents and liquid crystal elements.

[0007] The present invention has been made in view of the above problems, and one of its objectives is to provide a liquid crystal alignment agent that can produce a liquid crystal element that exhibits good liquid crystal alignment properties, has low charge accumulation and rapid residual charge relaxation, and can also produce a liquid crystal alignment film with high strength. [Means for solving the problem]

[0008] According to the present invention, the following liquid crystal alignment agents, liquid crystal alignment films, and methods for manufacturing the same, as well as liquid crystal elements and methods for manufacturing the same, are provided.

[0009] [1] A liquid crystal alignment agent containing the polymer (A) and the compound (B) described below. (A) Polymer: A polymer containing structural units derived from monomers having a substructure represented by the following formula (1). (B) Compound: A compound having a total of two or more groups F selected from the group consisting of a polymerizable carbon-carbon unsaturated bond-containing group, an isocyanate group, a protected isocyanate group, a cyclic carbonate group, a group having a ketene structure, a group having a Meldrum's acid structure, a cyclic ether group, a cyclic thioether group, an oxazoline group, a protected hydroxyalkylamide group, a protected thiol group, and a protected secondary amino group, and having no aromatic ring (however, excluding the polymer (A).) 1 having a total of two or more in one molecule and having no aromatic ring (however, excluding the polymer (A).)

Chemical formula

[0010] The liquid crystal alignment agent of the present invention makes it possible to obtain a liquid crystal element that exhibits good liquid crystal alignment, low charge accumulation, and rapid relaxation of residual charge. Furthermore, the liquid crystal alignment agent of the present invention makes it possible to obtain a liquid crystal alignment film with high strength. [Modes for carrying out the invention]

[0011] The following details the aspects of this disclosure.

[0012] In this specification, numerical ranges indicated using "~" include the values ​​indicated before and after "~" as the lower and upper limits, respectively. A "structural unit" is a unit that primarily constitutes the main chain structure and is present in at least two units within the main chain structure. Structural units are typically monomeric units. However, compounds obtained by reacting a monomeric unit having a reactive group with a compound having a functional group that can react with said reactive group are also included as "structural units."

[0013] In this specification, "hydrocarbon group" includes linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Linear hydrocarbon group" means a linear hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure and consists only of a linear structure. However, linear hydrocarbon groups may be saturated or unsaturated. "Alicyclic hydrocarbon group" means a hydrocarbon group that contains only the structure of an alicyclic hydrocarbon as its ring structure and does not contain an aromatic ring structure. However, an alicyclic hydrocarbon group does not have to consist only of the structure of an alicyclic hydrocarbon, and may also include those that have a linear structure as part of it. "Aromatic hydrocarbon group" means a hydrocarbon group that contains an aromatic ring structure as its ring structure. However, an aromatic ring hydrocarbon group does not have to consist only of an aromatic ring structure, and may include a linear structure or an alicyclic hydrocarbon structure as part of it. "Aromatic ring" means an aromatic hydrocarbon ring and an aromatic heterocycle. "Organic group" means an atomic group obtained by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound).

[0014] The "main chain" of a polymer refers to the "trunk" portion of the polymer, which consists of the longest chain of atoms. This "trunk" portion may contain a ring structure. For example, "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. "Side chains" refer to the parts of a polymer that branch off from the "trunk." "(meth)acrylic" is a term that encompasses acrylic and methacrylic, and "(meth)acrylate" is a term that encompasses acrylate and methacrylate.

[0015] Liquid crystal alignment agent The liquid crystal alignment agent of this disclosure contains a polymer (hereinafter also referred to as "(A) polymer") which includes structural units derived from monomers having a specific substructure, and a compound (hereinafter also referred to as "(B) compound") which has a total of two or more specific crosslinkable groups in one molecule and does not have an aromatic ring. The following describes each component contained in the liquid crystal alignment agent of this disclosure, and other components which may be optionally added as needed. Unless otherwise specified, each component may be used alone or in combination of two or more.

[0016] <(A) Polymer> (A) The polymer is a polymer that contains structural units (hereinafter also called "structural units (U)") derived from monomers having a substructure (hereinafter also called "substructure (S)") represented by the following formula (1). [ka] (In formula (1), Ar 1 Ar 2 and R 1 Ar 1 and Ar 2 is a divalent aromatic ring group, R 1 Is it a hydrogen atom or a monovalent organic group, or Ar 1 and Ar 2 When they are combined with each other, Ar 1 and Ar 2 This represents a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which it is bonded, R 1 is a hydrogen atom or a monovalent organic group, or Ar 1 and R 1 When they are combined with each other, Ar 2 and R 1 This represents a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which it is bonded, Ar 2 This is a divalent aromatic ring group. 1 These are alkanediyl groups with 1 to 10 carbon atoms, -O-, -S-, -CO-, -CO-O-, -CO-NR 2 -, -NR 2 -CO-O-, -CO-NR 2 -CO-, -NR 2 -CO-NR 3 -, or some methylene groups in an alkanediyl group having 2 to 10 carbon atoms are -O-, -S-, -CO-, -CO-O-, -CO-NR 2 -, -NR 2 -CO-O-, -CO-NR 2 -CO- or -NR 2 -CO-NR 3 It is a divalent group that has been replaced by -. R 2 and R 3Each of these is independently either a hydrogen atom or a monovalent organic group. (* represents a bond.)

[0017] In the above equation (1), Ar 1 Or Ar 2 The divalent aromatic ring group represented by is a group obtained by removing two hydrogen atoms from the ring portion of a substituted or unsubstituted aromatic ring. The aromatic ring may be either an aromatic hydrocarbon ring or an aromatic heterocycle. Furthermore, the aromatic ring may be a monocycle or a fused ring. Specific examples of aromatic hydrocarbon rings include benzene rings, naphthalene rings, anthracene rings, and phenanthrene rings. Specific examples of aromatic heterocycles include pyrrole rings, pyrazole rings, imidazole rings, 1,2,4-triazole rings, 1,2,3-triazole rings, pyridine rings, pyrimidine rings, pyridazine rings, pyrazine rings, 1,2,4-triazine rings, 1,3,5-triazine rings, 1,2,4-triazine rings, carbazole rings, benzimidazole rings, quinoline rings, isoquinoline rings, indole rings, purine rings, acridine rings, oxazole rings, thiazole rings, oxadiazole rings, benzothiazole rings, and the following formula [ka] Examples include nitrogen-containing heterocycles such as the ring represented by ; oxygen-containing heterocycles such as furan rings, benzofuran rings, dibenzofuran rings, oxazole rings, and oxadiazole rings; and sulfur-containing heterocycles such as thiophene rings, dibenzothiophene rings, thiazole rings, and benzothiazole rings.

[0018] Ar 1 Or Ar 2 The divalent aromatic ring group represented by is preferably an aromatic hydrocarbon ring or a nitrogen-containing heterocycle among the above, more preferably a benzene ring, naphthalene ring, pyrrole ring, pyrazole ring, imidazole ring, pyridine ring, pyrimidine ring, carbazole ring, benzimidazole ring or quinoline ring, even more preferably a benzene ring, pyridine ring or carbazole ring, and particularly preferably a benzene ring.

[0019] Ar 1 Or Ar 2Substituents that can be present in the divalent aromatic ring group represented by include C1-C5 alkyl groups, C1-C5 alkoxy groups, halogen atoms, hydroxyl groups, carboxyl groups, and thermally detachable groups (e.g., tert-butoxycarbonyl group).

[0020] R 1 The monovalent organic group represented is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms or a monovalent thermally desorbable group. Examples of monovalent hydrocarbon groups having 1 to 10 carbon atoms include monovalent linear hydrocarbon groups having 1 to 10 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 10 carbon atoms, and monovalent aromatic hydrocarbon groups having 6 to 10 carbon atoms. Among these, alkyl groups, cyclohexyl groups, or phenyl groups having 1 to 6 carbon atoms are preferred, alkyl groups having 1 to 6 carbon atoms are more preferred, and alkyl groups having 1 to 3 carbon atoms are even more preferred.

[0021] R 1 Examples of monovalent thermally detachable groups represented by include tert-butoxycarbonyl group (Boc group), benzyloxycarbonyl group, 1,1-dimethyl-2-haloethyloxycarbonyl group, allyloxycarbonyl group, 2-(trimethylsilyl)ethoxycarbonyl group, and 9-fluorenylmethyloxycarbonyl group (F-moc group). Of these, the Boc group is preferred because it exhibits excellent thermal detachment properties and can reduce the amount of residual structure in the film after detachment.

[0022] Ar 1 and Ar 2 When they are combined with each other, Ar 1 and Ar 2 When representing a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which it is bonded, the nitrogen-containing aromatic condensed ring structure is as follows: Examples include carbazole ring structures and 2,3-benzocarbazole ring structures. Among these, the carbazole ring structure is preferred.

[0023] Ar 1 and R 1 When they are combined with each other, Ar 1 and R 1When representing a nitrogen-containing aromatic condensed ring structure composed of a nitrogen atom to which it is bonded, examples of the nitrogen-containing aromatic condensed ring structure include an indole ring structure, a benzimidazole ring structure, a carbazole ring structure, and the like. Among them, a carbazole ring structure is preferable.

[0024] X 1 From the viewpoint of obtaining a liquid crystal element showing good liquid crystal alignment and from the viewpoint of the ease of synthesis of the skeleton constituting the partial structure (S), among the above, an alkanediyl group having 1 to 8 carbon atoms, -O-, -CO-O-, -CO-NR 2 -, -NR 2 -CO-NR 3 -, and a divalent group in which some of the methylene groups in the alkanediyl group having 2 to 8 carbon atoms are replaced by -O-, -CO-O-, -CO-NR 2 -, or -NR 2 -CO-NR 3 - is preferably a divalent group. From the viewpoint of obtaining a liquid crystal element showing good liquid crystal alignment, X 1 is preferably an alkanediyl group having 1 to 8 carbon atoms, -O-, -CO-O-, -CO-NR 2 -, and a divalent group in which some of the methylene groups in the alkanediyl group having 2 to 8 carbon atoms are replaced by -CO-O- or -CO-NR 2 - is more preferably a divalent group. Further, from the viewpoint of obtaining a liquid crystal element with less charge accumulation and rapid relaxation of residual charge, X 1 is preferably an alkanediyl group having 1 to 8 carbon atoms, -O-, -CO-NR 2 -, and a divalent group in which some of the methylene groups in the alkanediyl group having 2 to 8 carbon atoms are replaced by -O- or -CO-NR 2 - is more preferably a divalent group.

[0025] R 2 and R 3 As the monovalent organic group represented by, the description of the monovalent organic group represented by the above R 1 is applicable.

[0026] Specific examples of the substructure represented by formula (1) above include the structures represented by formulas (1-1) to (1-14) below, and structures having substituents on the ring portion of the structure represented by the following formulas. In the structural formulas, "Boc" represents a tert-butoxycarbonyl group (the same applies below). [ka] (In formulas (1-1) to (1-14), X 1 This is equivalent to equation (1) above. "*" represents a bond.

[0027] From the viewpoint of obtaining a liquid crystal element that accumulates less charge and can relieve residual charge more quickly, it is preferable that the polymer (A) contains the substructure (S) in its main chain.

[0028] (A) A polymer only needs to contain structural units (U), and its main skeleton is not particularly limited. Examples of the main skeleton of a polymer include polyamic acid, polyamic acid esters, polyimides, polyorganosiloxanes, polyesters, polyamides, polyamideimides, polybenzoxazole precursors, polybenzoxazoles, cellulose derivatives, polyacetals, and addition polymers. Addition polymers are polymers that contain structural units derived from monomers having polymerizable unsaturated carbon-carbon bonds, and examples include styrene polymers, (meth)acrylic polymers, maleimide polymers, (meth)acrylic-styrene copolymers, (meth)acrylic-maleimide copolymers, (meth)acrylic-styrene-maleimide copolymers, and styrene-maleimide copolymers.

[0029] (A) The main skeleton of the polymer is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, from the viewpoint of having good heat resistance, mechanical strength, affinity with liquid crystals, and more preferably at least one selected from the group consisting of polyamic acid and polyimide.

[0030] Next, polyamic acids, polyamic acid esters, and polyimides as (A) polymers included in the liquid crystal alignment agent of this disclosure will be described. When the (A) polymer is at least one selected from the group consisting of polyamic acids, polyamic acid esters, and polyimides, the (A) polymer can be obtained, for example, by a method including a step of condensation polymerization of a tetracarboxylic dianhydride and a diamine.

[0031] [Polyamic acid] (A) When the polymer is a polyamic acid, a polyamic acid containing a structural unit (U) (hereinafter also referred to as "polyamic acid (A)") can be obtained by polymerization using a monomer having a substructure (S). Methods for producing polyamic acid (A) include, for example, [1] polymerizing a monomer containing a tetracarboxylic dianhydride having a substructure (S); and [2] polymerizing a monomer containing a diamine having a substructure (S) (hereinafter also referred to as "specific diamine"). Of these, method [2] is preferred because it allows for a wide range of monomer options and the monomers are relatively easy to obtain or synthesize.

[0032] (Tetracarboxylic acid dianhydride) Examples of tetracarboxylic dianhydrides used in the synthesis of polyamic acid (A) include aliphatic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides. Examples of aliphatic tetracarboxylic dianhydrides include linear tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides.

[0033] Specific examples of these include linear tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride; Examples of alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, and 3-oxabic Chlo[3.2.1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, 4,9-dioxatricyclo[5.3.1.02,6]undecane-3,5,8,10-tetraone, cyclohexanetetracarboxylic acid dianhydride, etc. Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol bisanhydrotrimate, 4,4'-carbonyl diphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, etc., as well as the tetracarboxylic dianhydride described in Japanese Patent Application Publication No. 2010-97188.

[0034] The tetracarboxylic dianhydride is preferably an aromatic tetracarboxylic dianhydride. (A) It is preferable that the polymer contains structural units derived from the aromatic tetracarboxylic dianhydride, as this allows for the creation of a liquid crystal element with less charge accumulation and faster residual charge relaxation. Among the above, at least one selected from the group consisting of pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride is preferred as the aromatic tetracarboxylic dianhydride.

[0035] (A) In polymer, the content of structural units derived from aromatic tetracarboxylic dianhydride is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more, relative to the total amount of structural units derived from tetracarboxylic dianhydride constituting polymer (A), from the viewpoint of obtaining a liquid crystal element that accumulates less charge and can relieve residual charge more quickly. Furthermore, from the viewpoint of the solubility of polymer (A), the content of structural units derived from aromatic tetracarboxylic dianhydride is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 80 mol% or less, relative to the total amount of structural units derived from tetracarboxylic dianhydride constituting polymer (A).

[0036] (Diamine) For the synthesis of polyamic acids, specific diamines can be preferably used. The specific diamine only needs to have a substructure (S), and its other structures are not particularly limited. Furthermore, the number of substructures (S) that the specific diamine has is not particularly limited. In order to obtain sufficient improvements in reducing accumulated charge and mitigating residual charge, it is preferable that the specific diamine constituting the polymer (A) has a substructure (S) in its main chain. Specific examples of specific diamines include, for example, the compound represented by the following formula (A-1), the compound represented by the following formula (A-2), and the compound represented by the following formula (A-3). [ka] (In formulas (A-1), (A-2), and (A-3), B 1 is the partial structure represented by the above formula (1). However, B in formulas (A-1) and (A-3) 1 is X in formula (1) 1 when X 3 is Ar 6 or Ar 3 and is bonded to Ar 4 Ar 5 is a divalent aromatic ring group. Ar 6 Ar 7 and R 2 are such that Ar 6 and Ar 7 are divalent aromatic ring groups, R 2 is a hydrogen atom or a monovalent organic group, or Ar 6 and Ar 7 are combined with each other to represent a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which Ar 6 and Ar 7 are bonded, and R 2 is a hydrogen atom or a monovalent organic group, or Ar 7 and R 2 are combined with each other to represent a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which Ar 7 and R 2 are bonded, and Ar 6 is a divalent aromatic ring group. The two Bs in formula (A-2) 1 are the same or different.)

[0037] In the above formula (A-2), X in the above formula (1) 1 may be bonded to Ar 4 or Ar 5 , and may also be bonded to X in another formula (1) 1 or Ar in another formula (1) 1 . Among them, from the viewpoints of less charge accumulation and ease of synthesis of specific diamines, it is preferable that it is bonded to Ar 4 or Ar 5 .

[0038] In the above equations (A-1), (A-2), and (A-3), Ar 3 Ar 4 Ar 5 Ar 6 and Ar 7 The divalent aromatic ring group represented by is the Ar in formula (1) above. 1 and Ar 2 The description of the divalent aromatic ring group represented by applies. R 2 As a monovalent organic group represented by the above formula (1), R 1 The explanation of a monovalent organic group represented by applies. Ar 6 and Ar 7 When they are combined with each other, Ar 6 and Ar 7 The nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which it is bonded is the Ar in formula (1) above. 1 and Ar 2 When they are combined with each other, Ar 1 and Ar 2 The explanation of nitrogen-containing aromatic condensed ring structures, which are formed together with the nitrogen atom to which they are bonded, is applicable. Ar 7 and R 2 When they are combined with each other, Ar 7 and R 2 The nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which it is bonded is the Ar in formula (1) above. 1 and R 1 When they are combined with each other, Ar 1 and R 1 The explanation of nitrogen-containing aromatic condensed ring structures, which are formed together with the nitrogen atom to which they are bonded, is applicable.

[0039] Specific examples of specific diamines include the compounds represented by the following formulas (A-1-1) to (A-1-7), (A-2-1) to (A-2-4), and (A-3-1) to (A-3-6), respectively. [ka] [ka] [ka]

[0040] The specific diamine is preferably a compound represented by the above formula (A-3) because it exhibits an excellent balance between liquid crystal orientation and various properties such as charge accumulation and residual charge relaxation.

[0041] The diamine used in the synthesis of polyamic acid (A) may be a specific diamine only, but diamines without a substructure (S) (hereinafter also referred to as "other diamines") may also be used in combination. Examples of other diamines include aliphatic diamines, aromatic diamines, and diaminoorganosiloxanes. Aliphatic diamines include linear diamines and alicyclic diamines.

[0042] Other specific examples of diamines include, as chain-like diamines, metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, etc. Examples of alicyclic diamines include 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine);

[0043] Examples of aromatic diamines include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-diaminodiphenyl ether, 1,3-bis(4-aminophenoxy)propane, and 9,9-bis(4-aminophenyl Fluorene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 4,4'-(p-phenylenediisopropylidene)bisaniline, 1,4-bis(4-aminophenoxy)benzene, 2,6-diaminopyridine, 3,6-diaminocarbazole, N,N'-bis(4-aminophenyl)-benzidine, 1,4-bis-(4-aminophenyl)-piperazine, 1-(4-aminophenyl)-2,3-diaminophenyl Dro-1,3,3-trimethyl-1H-indene-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine, 3,5-diaminobenzoic acid, cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestanyl 3,5-diaminobenzoate Nyl, 3,5-Lanostanyl diaminobenzoate, 3,6-Bis(4-aminobenzoyloxy)cholestane, 4-(4'-Trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-Bis(4-((aminophenyl)methyl)phenyl)-4-heptylcyclohexane, 2,4-Diamino-N,N-Diallylaniline, 4-Aminobenzylamine, Cinnamic acid structure-containing diamines and the following formula (E-1), [ka] (In formula (E-1), X I and X II These are, independently, a single bond, -O-, *-COO-, or *-OCO- (where "*" represents a bond with the diaminophenyl group). I This is an alkanediyl group with 1 to 3 carbon atoms. IIR is a single bond or an alkanediyl group having 1 to 3 carbon atoms. III (where a is an alkyl group, alkoxy group, fluoroalkyl group, or fluoroalkoxy group having 1 to 20 carbon atoms. a is 0 or 1. b is an integer between 0 and 3. c is an integer between 0 and 2. d is 0 or 1. However, 1 ≤ a + b + c ≤ 3.) Compounds represented by; Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and diamines described in Japanese Patent Publication No. 2010-97188 can also be used.

[0044] In the above equation (E-1), "-X I -(R I -X II ) d The divalent group represented by "-" is preferably an alkanediyl group having 1 to 3 carbon atoms, *-O-, *-COO-, or *-O-C2H4-O- (where the bond with "*" is bonded to a diaminophenyl group). III The group represented by is preferably linear. The two amino groups in the diaminophenyl group are preferably located at the 2,4- or 3,5-positions relative to the other group.

[0045] Specific examples of compounds represented by the above formula (E-1) include, for example, the compounds represented by the following formulas (E-1-1) to (E-1-4). [ka]

[0046] When using a specific diamine in the synthesis of polyamic acid (A), the proportion of the specific diamine used is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, and particularly preferably 15 mol% or more, relative to the total amount of diamine used in the synthesis of polyamic acid (A), from the viewpoint of obtaining a liquid crystal element with low charge accumulation and rapid relaxation of residual charge. Furthermore, the proportion of the specific diamine used is preferably 90 mol% or less, more preferably 80 mol% or less, even more preferably 70 mol% or less, and particularly preferably 60 mol% or less, relative to the total amount of diamine used in the synthesis of polyamic acid (A).

[0047] (Synthesis of polyamic acids) Polyamic acid (A) can be obtained by reacting the above-mentioned tetracarboxylic dianhydride with a diamine, along with a molecular weight adjusting agent as needed. The ratio of tetracarboxylic dianhydride to diamine used in the synthesis reaction of polyamic acid (A) is preferably such that the acid anhydride groups of the tetracarboxylic dianhydride are 0.2 to 2 equivalents, and more preferably 0.3 to 1.2 equivalents, per 1 equivalent of the amino groups of the diamine.

[0048] Examples of molecular weight modifiers include acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The proportion of molecular weight modifier used is preferably 20 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the total amount of tetracarboxylic dianhydride and diamine used.

[0049] The synthesis reaction of polyamic acids is preferably carried out in an organic solvent. The reaction temperature is preferably -20°C to 150°C, and more preferably 0 to 100°C. The reaction time is preferably 0.1 to 24 hours, and more preferably 0.5 to 12 hours.

[0050] Examples of organic solvents used in the reaction include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Of these organic solvents, it is preferable to use one or more selected from the group consisting of aprotic polar solvents and phenolic solvents (organic solvents of group 1), or a mixture of one or more selected from organic solvents of group 1 and one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons (organic solvents of group 2). In the latter case, the proportion of organic solvents of group 2 used is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, relative to the total amount of organic solvents of group 1 and group 2.

[0051] Particularly preferred organic solvents are one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenol, or a mixture of one or more of these and other organic solvents within the above proportion range. The amount of organic solvent used (x) is preferably such that the total amount of tetracarboxylic dianhydride and diamine (y) is 0.1 to 50% by mass of the total amount of the reaction solution (x+y).

[0052] As described above, a reaction solution is obtained by dissolving polyamic acid. This reaction solution may be used as is for the preparation of a liquid crystal alignment agent, or the polyamic acid contained in the reaction solution may be isolated and then used for the preparation of the liquid crystal alignment agent, or the isolated polyamic acid may be purified and then used for the preparation of the liquid crystal alignment agent. When dehydrating and cyclizing the polyamic acid to obtain polyimide, the above reaction solution may be used as is for the dehydration and cyclization reaction, or the polyamic acid contained in the reaction solution may be isolated and then used for the dehydration and cyclization reaction, or the isolated polyamic acid may be purified and then used for the dehydration and cyclization reaction. The isolation and purification of polyamic acid can be carried out according to known methods.

[0053] [Polyamic acid ester] (A) Polyamic acid esters as polymers can be obtained, for example, by [I] reacting the polyamic acid (A) obtained by the above synthesis reaction with an esterifying agent, [II] reacting a tetracarboxylic acid diester with a diamine, [III] reacting a tetracarboxylic acid dihalide with a diamine, etc. The polyamic acid ester to be contained in the liquid crystal alignment agent may have only an amic acid ester structure, or it may be a partially esterified product in which both an amic acid structure and an amic acid ester structure coexist. The reaction solution obtained by dissolving the polyamic acid ester may be used as is for the preparation of the liquid crystal alignment agent, or the polyamic acid ester contained in the reaction solution may be isolated and then used for the preparation of the liquid crystal alignment agent, or the isolated polyamic acid ester may be purified and then used for the preparation of the liquid crystal alignment agent. Isolation and purification of polyamic acid esters can be carried out according to known methods.

[0054] [Polyimide] (A) Polyimides as polymers can be obtained, for example, by dehydrating and cyclizing the polyamic acid (A) synthesized as described above to form imidates.

[0055] The polyimide may be a fully imidized product obtained by dehydrating and cyclizing all of the amic acid structure present in its precursor, polyamic acid (A), or it may be a partially imidized product in which only a portion of the amic acid structure is dehydrated and cyclized, resulting in the coexistence of amic acid and imide ring structures. The polyimide contained in the liquid crystal alignment agent of this disclosure preferably has an imidization rate of 20% or more, more preferably 30-90%, and even more preferably 40-80%. This imidization rate is expressed as a percentage of the ratio of the number of imide ring structures to the total number of amic acid structures and imide ring structures in the polyimide. Here, a portion of the imide ring may be an isoimide ring.

[0056] Dehydration and ring closure of polyamic acid (A) is preferably carried out by heating polyamic acid (A), or by dissolving polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst to the solution, and heating as necessary.

[0057] In a method of adding a dehydrating agent and a dehydration ring-closing catalyst to a solution of polyamic acid (A), the dehydrating agent can be an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride. The amount of dehydrating agent used is preferably 0.01 to 20 moles per mole of the amic acid structure of polyamic acid (A). As the dehydration ring-closing catalyst, a tertiary amine such as pyridine, colidine, lutidine, triethylamine, or 1-methylpiperidine can be used. The amount of dehydration ring-closing catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. Examples of organic solvents used in the dehydration ring-closing reaction include those exemplified as those used in the synthesis of polyamic acid (A). The reaction temperature for the dehydration ring-closing reaction is preferably 0 to 180°C, more preferably 10 to 150°C. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

[0058] In this way, a reaction solution containing polyimide is obtained. This reaction solution may be used as is for the preparation of the liquid crystal alignment agent, or the dehydrating agent and dehydration ring-closing catalyst may be removed from the reaction solution before preparing the liquid crystal alignment agent, or the polyimide may be isolated before preparing the liquid crystal alignment agent, or the isolated polyimide may be purified before preparing the liquid crystal alignment agent. These purification operations can be carried out according to known methods. In addition, polyimide can also be obtained by imidization of polyamic acid esters.

[0059] The (A) polymers obtained as described above preferably have a solution viscosity of 20 to 1,800 mPa·s when prepared as a 15% by mass solution, and more preferably have a solution viscosity of 50 to 1,500 mPa·s. The solution viscosity (mPa·s) of the polyamic acid, polyamic acid ester, and polyimide is measured at 25°C using an E-type rotational viscometer for a 15% by mass polymer solution prepared using a good solvent (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0060] (A) The weight-average molecular weight (Mw) of polyamic acid, polyamic acid ester, and polyimide as polymers, measured by gel permeation chromatography (GPC), is preferably 1,000 to 500,000, and more preferably 2,000 to 300,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) measured by GPC, is preferably 8 or less, and more preferably 6 or less. By having Mw and Mw / Mn within the above ranges, good liquid crystal alignment of the liquid crystal element can be ensured.

[0061] The content of polyamic acid, polyamic acid ester, and polyimide as (A) polymers in the liquid crystal alignment agent of this disclosure is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on the total amount of solids contained in the liquid crystal alignment agent (components other than the solvent component of the liquid crystal alignment agent).

[0062] <(B) Compound> (B) The compound is a crosslinkable group selected from the group consisting of polymerizable carbon-carbon unsaturated bond-containing groups, isocyanate groups, protected isocyanate groups, cyclic carbonate groups, groups having a ketene structure, groups having a meldrum acid structure, cyclic ether groups, cyclic thioether groups, oxazoline groups, protected hydroxyalkylamide groups, protected thiol groups, and protected secondary amino groups (hereinafter referred to as "group F"). 1 A compound having a total of two or more of (also known as) in one molecule and lacking an aromatic ring (excluding the polymers described in (A) above).

[0063] The polymerizable carbon-carbon unsaturated bond-containing group is preferably a group represented by any of the following formulas (g1-1) to (g1-10), as it has high crosslinking reactivity and can be used to obtain a liquid crystal alignment film with excellent liquid crystal alignment and voltage retention properties. [ka] (In equations (g1-1) to (g1-10), "*" represents a combination.)

[0064] (B) Among the polymerizable carbon-carbon unsaturated bond-containing groups of the compound, the group represented by any of the above formulas (g1-1) to (g1-7) is preferred, and the group represented by any of the above formulas (g1-1) to (g1-4) is more preferred in terms of high crosslinking reactivity and ease of introducing functional groups.

[0065] In the case of protected isocyanate groups, it is preferable that the isocyanate group is protected by a thermally leaving group. Known reagents can be used to obtain the protected isocyanate by reaction with the isocyanate group (hereinafter also referred to as "blocking agents"). Specific examples of blocking agents include, for example, alcohols, phenols, active methylene compounds, mercaptans, acid amides, acid imides, imidazoles, pyrazoles, ureas, oximes, amines, imines, and pyridines. From the viewpoint of suppressing the retention of components derived from groups that are removed by heating during film formation in the film, the thermally leaving group preferably has 1 to 10 carbon atoms, and more preferably 1 to 6 carbon atoms.

[0066] Examples of cyclic ether groups include oxyranyl groups and oxetanyl groups. Examples of cyclic carbonate groups include ethylene carbonate groups and propylene carbonate groups.

[0067] In protected hydroxyalkylamide groups, it is preferable that the hydroxyalkylamide group is protected by a thermally leaving group. Furthermore, it is preferable that it be a protected β-hydroxyalkylamide group. The thermally leaving group can be any group that leaves upon heat and is replaced by a hydrogen atom, but examples include ether-based leaving groups such as methyl, ethyl, tert-butyl, benzyl, p-methoxybenzyl, and trityl groups; acetal-based leaving groups such as methoxymethyl, ethoxyethyl, and 2-tetrahydropyranyl groups; acyl-based leaving groups such as acetyl, pivaloyl, benzoyl, and trichloroacetyl groups; allyl-based leaving groups such as allyl and methallyl groups; carbamate-based leaving groups such as tert-butoxycarbonyl groups; and silyl ether-based leaving groups such as trimethylsilyl, triethylsilyl, and tert-butyldimethylsilyl groups. From the viewpoint of achieving both ease of detachment by heat and storage stability, ether-based leaving groups, acetal-based leaving groups, carbamate-based leaving groups, or acetyl groups are preferred, and C4-C7 alkyl groups, 2-tetrahydropyranyl groups, methoxymethyl groups, 1-ethoxyethyl groups, acetyl groups, or tert-butoxycarbonyl groups are more preferred.

[0068] The protected secondary amino group is preferably protected by a thermally leaving group. The thermally leaving group is R in formula (1) above. 1 The explanation of monovalent thermally leaving groups represented by applies.

[0069] Group F 1 Among the above, it is preferable that the group is at least one selected from the group consisting of polymerizable carbon-carbon unsaturated bond-containing groups, cyclic carbonate groups, cyclic ether groups, protected hydroxyalkylamide groups, protected thiol groups, and protected secondary amino groups, and more preferably at least one selected from the group consisting of polymerizable carbon-carbon unsaturated bond-containing groups, cyclic carbonate groups, cyclic ether groups, protected hydroxyalkylamide groups, and protected thiol groups. Furthermore, from the viewpoint of obtaining a liquid crystal element with less charge accumulation and faster residual charge relaxation, and from the viewpoint of obtaining a liquid crystal alignment film with higher strength, it is even more preferable that the group is at least one selected from the group consisting of polymerizable carbon-carbon unsaturated bond-containing groups, cyclic ether groups, and protected hydroxyalkylamide groups, and from the viewpoint of obtaining better liquid crystal alignment, it is particularly preferable that the group is at least one selected from the group consisting of cyclic ether groups and protected hydroxyalkylamide groups.

[0070] (B) Group F of the compound 1 The number of groups is preferably three or more in total per molecule, and more preferably four or more in total, from the viewpoint of obtaining a liquid crystal element with low charge accumulation and rapid residual charge relaxation, and from the viewpoint of obtaining a liquid crystal alignment film with excellent strength. Also, the group F of compound (B) 1 From the viewpoint of storage stability of the liquid crystal alignment agent, the total number of these elements is preferably 10 or less, and more preferably 8 or less. (B) From the viewpoint of storage stability, the molecular weight of the compound is preferably 2,000 or less, more preferably 1,500 or less, and even more preferably 1,000 or less.

[0071] (B) Preferred specific examples of compounds include those represented by the following formula (2). R 5 -(Z 1 ) m …(2) (In formula (2), Z 1 R is a polymerizable carbon-carbon unsaturated bond-containing group, isocyanate group, protected isocyanate group, cyclic carbonate group, ketene group, meldrum acid group, cyclic ether group, cyclic thioether group, oxazoline group, protected hydroxyalkylamide group, protected thiol group, or protected secondary amino group. 5 is an m-valence organic group, where m is an integer greater than or equal to 2. Multiple Z in equation (2) 1 They are either the same or different.

[0072] In equation (2) above, R 5 The m-valent organic group represented by preferably has 1 to 40 carbon atoms. The m-valent organic group is an m-valent hydrocarbon group having 1 to 40 carbon atoms, in which some of the methylene groups are -O-, -S-, -CO-, -CO-O-, -NR 6 -,-CO-NR 6 -, -NR 6 -CO-O-, -NR 6 -CO-NR 7 -,-CO-NR 6 Examples include -CO- or m-valence groups that are replaced by a heterocycle. R 6 and R 7 R is a hydrogen atom or a monovalent thermally leaving group. As a monovalent thermally leaving group, R in formula (1) above is... 1 The explanation of monovalent thermally leaving groups represented by applies.

[0073] Z 1 It is preferably at least one selected from the group consisting of polymerizable carbon-carbon unsaturated bond-containing groups, cyclic ether groups, and protected hydroxyalkylamide groups, and more preferably at least one selected from the group consisting of cyclic ether groups and protected hydroxyalkylamide groups. From the viewpoint of obtaining a liquid crystal alignment film with higher strength, m is preferably 3 or more, and more preferably 4 or more. Furthermore, from the viewpoint of storage stability of the liquid crystal alignment agent, m is preferably 10 or less, and more preferably 8 or less.

[0074] (B) Specific examples of compounds include compounds having polymerizable carbon-carbon unsaturated bond-containing groups, such as ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and compounds represented by the following formulas (2A-1) to (2A-5); Examples of compounds having an isocyanate group or a protected isocyanate group include the compounds represented by formulas (2B-1) and (2B-2) below; Examples of compounds having a cyclic carbonate group include those represented by formulas (2C-1) to (2C-6) below; Examples of compounds having a group with a meldramic acid structure include compounds represented by the following formula (2D-1); Examples of compounds having a cyclic ether group 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-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and N,N,N',N'-tetraglycidyl-4,4'-dia Minodiphenylmethane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether, N,N-diglycidyl-benzylamine, N,N-diglycidyl-aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine, epoxidation reaction products of pentaerythritol tetraallyl ether with hydrogen peroxide, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, and compounds represented by formulas (2E-1) to (2E-5) below, respectively; Examples of compounds having a protected hydroxyalkylamide group include those represented by formulas (2F-1) to (2F-5) below; Examples of compounds having a protected thiol group include those represented by formulas (2G-1) and (2G-2) below; Examples of compounds having a protected secondary amino group include compounds represented by the following formula (2H-1). [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] (In formula (2A-2), R 9 is a hydrogen atom or an acryloyl group. In equations (2B-1) and (2B-2), R 10 It is a thermally leaving group. In equation (2C-6), b is an integer between 1 and 10.

[0075] In the liquid crystal alignment agent of this disclosure, the content of compound (B) is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, and particularly preferably 5% by mass or more, based on the total amount of polymer components contained in the liquid crystal alignment agent, from the viewpoint of minimizing charge accumulation and accelerating residual charge relaxation, as well as improving film strength. Furthermore, from the viewpoint of improving storage stability, the content of compound (B) is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

[0076] <Other ingredients> The liquid crystal alignment agent of this disclosure may contain, in addition to (A) polymer and (B) compound, other components as needed. Examples of other components include polymers different from polymer (A) (hereinafter also referred to as "other polymers"), solvents, crosslinking agents different from compound (B) (hereinafter also referred to as "other crosslinking agents"), antioxidants, metal chelating compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, and the like. The content ratio of the other components can be appropriately selected depending on each compound, as long as it does not impair the effects of the present invention.

[0077] [Other polymers] Other polymers may be polymers that do not contain structural units (U), and their main skeleton is not particularly limited. Examples of the main skeleton of other polymers are the same as those of polymer (A) above. Among these, from the viewpoint of obtaining liquid crystal elements that are excellent in various properties such as liquid crystal alignment when used together with polymer (A), polymers that have structural units derived from diamine compounds and do not contain structural units (U) can be preferably used as other polymers. Examples of such other polymers include polyamic acid, polyamic acid esters, polyimides, polyamines, polyenamines, polyamides, polyamideimides, and polyureas.

[0078] Furthermore, from the viewpoint of obtaining highly reliable liquid crystal elements, the other polymer is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and is a polymer that does not have structural units (U) (hereinafter also referred to as "(C) polymer"). Among these, at least one selected from the group consisting of polyamic acid and polyimide is more preferred from the viewpoint of good liquid crystal alignment and reliability. The explanations other than the explanation regarding specific diamines in the (A) polymer above apply to the polyamic acid, polyamic acid ester, and polyimide as the (C) polymer.

[0079] (C) The polymer preferably contains structural units derived from a tetracarboxylic dianhydride having a cyclobutane ring structure (hereinafter also referred to as "cyclobutanetetracarboxylic dianhydride"), from the viewpoint of obtaining a liquid crystal alignment film that exhibits excellent liquid crystal alignment when a photo-alignment method is applied. Specific examples of cyclobutanetetracarboxylic dianhydrides include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, methyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 1,3-diethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride. Among these, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride is preferred in that it can increase the photoreactivity of the coating film formed using the liquid crystal alignment agent.

[0080] Furthermore, (C) polymers can improve the reliability of liquid crystal elements, and are referred to as "-NR 4 - represents a base (where R 4 (C) The polymer is preferably a leaving group. (C) From the viewpoint of making the reliability of the liquid crystal element higher, it is "-NR 4 It is preferable that the main chain has a group represented by "-". (C) Polymer has "-NR 4 When introducing a base represented by "-", use "-NR 4 It is preferable to use a diamine having a group represented by "-" (hereinafter also referred to as "diamine (AN)"). 4 The group represented by "-" is different from the two primary amines that diamines possess. That is, diamine (AN) is represented by "-NR 4 It has a group represented by "-" and two primary amino groups.

[0081] R 4 The leaving group represented by is preferably a thermally leaving group. As a thermally leaving group, R in formula (1) above is preferable. 1 The explanation of monovalent thermally leaving groups represented by applies.

[0082] (C) If the polymer contains structural units derived from cyclobutanetetracarboxylic dianhydride, the content of these units is preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more, relative to the tetracarboxylic dianhydride used in the synthesis of the polymer (C).

[0083] (C) Polymer is "-NR 4 When the polymer has a group represented by "-", the content of structural units derived from diamine (AN) is preferably 10 mol% or more, and more preferably 20 mol% or more, relative to the total amount of structural units derived from diamine contained in the (C) polymer. Furthermore, the content of structural units derived from diamine (AN) is preferably 80 mol% or less, and more preferably 70 mol% or less, relative to the total amount of structural units derived from diamine contained in the (C) polymer.

[0084] When the liquid crystal alignment agent contains polymer (C), the content of polymer (C) is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 5% by mass or more, relative to the total amount of polymer (A) and polymer (C). Furthermore, the content of polymer (C) is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less, relative to the total amount of polymer (A) and polymer (C).

[0085] When imparting liquid crystal alignment ability to a liquid crystal alignment film formed using a liquid crystal alignment agent using a photo-alignment method, it is preferable that at least a portion of polymer (A) and polymer (C) be polymers having photo-aligning groups. A photo-aligning group refers to a functional group that can impart anisotropy to the film through photoreactions such as photoisomerization, photodimerization, photofleece rearrangement, or photodegradation reactions induced by light irradiation.

[0086] Specific examples of photo-directing groups include, for example, azobenzene-containing groups with azobenzene or its derivative as a basic skeleton, cinnamic acid structure-containing groups with cinnamic acid or its derivative (cinnamic acid structure) as a basic skeleton, chalcone-containing groups with chalcone or its derivative as a basic skeleton, benzophenone-containing groups with benzophenone or its derivative as a basic skeleton, coumarin-containing groups with coumarin or its derivative as a basic skeleton, cyclobutane-containing structures with cyclobutane or its derivative as a basic skeleton, stilbene-containing groups with stilbene or its derivative as a basic skeleton, and phenylbenzoate-containing groups with phenylbenzoate or its derivative as a basic skeleton. Of these, the photo-directing group is preferably at least one selected from the group consisting of azobenzene-containing groups, cinnamic acid structure-containing groups, chalcone-containing groups, stilbene-containing groups, cyclobutane-containing structures, and phenylbenzoate-containing groups, and the cinnamic acid structure-containing group or the cyclobutane-containing structure is preferred in terms of high sensitivity to light and ease of introduction into polymers.

[0087] The method for synthesizing polymers having photo-directing groups is not particularly limited. Polymers having photo-directing groups can be obtained, for example, by (1) polymerization using monomers having photo-directing groups; or by (2) synthesizing a polymer having a first functional group (e.g., an epoxy group) in its side chain, and reacting the first functional group-containing polymer obtained by said synthesis with a reactive compound having a second functional group (e.g., a carboxyl group) that forms a bond with the first functional group and a photo-directing group.

[0088] [solvent] The liquid crystal alignment agent of this disclosure is preferably prepared as a liquid composition in which (A) a polymer, (B) a compound and optionally added components are dissolved in a solvent. The solvent is preferably an organic solvent, such as aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc. Specific examples of organic solvents used include, for example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, and ethylene glycol-n Examples include 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, cyclohexanone, diisobutyl ketone, 3-methoxy-1-butanol, etc.

[0089] [Other crosslinking agents] Other crosslinking agents include base F. 1 It does not have base F 1 Compounds having a total of two or more crosslinking groups different from the group F in one molecule, 1 Each molecule contains one F group 1 Compounds having one or more crosslinking groups different from the above in one molecule, and group F 1 Examples include compounds having two or more aromatic rings in a single molecule.

[0090] Group F 1Examples of crosslinking groups different from those mentioned above include hydroxyl groups, protected hydroxyl groups, methylol groups, protected methylol groups, mercapto groups, protected mercapto groups, amino groups, protected primary amino groups, β-hydroxyalkylamide groups, β-alkoxyalkylamide groups, aldehyde groups, carbodiimide groups, protected carboxyl groups, silanol groups, and alkoxysilyl groups. Other crosslinking groups (group F) possessed by crosslinking agents are also mentioned. 1 The number of (including) is preferably two or more in total, more preferably 2 to 12 in total, and even more preferably 2 to 10 in total.

[0091] Other specific examples of crosslinking agents include compounds represented by formulas (c-1) to (c-12) below. [ka] [ka] (In formula (c-6), Ac represents an acetyl group.) [ka]

[0092] When other crosslinking agents are incorporated into the liquid crystal alignment agent, the content of the other crosslinking agents is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, relative to the total amount of polymer components. Furthermore, the content of the other crosslinking agents is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, relative to the total amount of compound (B) and the other crosslinking agents.

[0093] The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of components other than the solvent to the total mass of the liquid crystal alignment agent) is appropriately selected considering viscosity, volatility, etc., but is preferably in the range of 1 to 10% by mass. When the solid content concentration is 1% by mass or more, a sufficient film thickness can be ensured for the coating, and a liquid crystal alignment film exhibiting good liquid crystal alignment properties is easily obtained. On the other hand, when the solid content concentration is 10% by mass or less, the coating can be made of an appropriate thickness, a liquid crystal alignment film exhibiting good liquid crystal alignment properties is easily obtained, and the viscosity of the liquid crystal alignment agent tends to be appropriate, resulting in good coatability.

[0094] <Liquid crystal alignment film, method for manufacturing the same, and liquid crystal element> The liquid crystal alignment film of this disclosure is formed from a liquid crystal alignment agent prepared as described above. The liquid crystal element of this disclosure comprises a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The operating mode of the liquid crystal in the liquid crystal element is not particularly limited and can be applied to various modes such as TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS (In-Plane Switching) type, FFS (Fringe Field Switching) type, OCB (Optically Compensated Bend) type, and PSA (Polymer Sustained Alignment) type. The liquid crystal element can be manufactured by a method including, for example, the following steps 1 to 3. In step 1, the substrate used differs depending on the desired operating mode. Steps 2 and 3 are common to each operating mode.

[0095] <Step 1: Formation of the coating> First, a liquid crystal alignment agent is applied to the substrate, and preferably the applied surface is heated to form a coating on the substrate. For example, transparent substrates made of glass such as float glass or soda glass, or resins such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or poly(alicyclic olefin) can be used as the substrate. As the transparent conductive film provided on one surface of the substrate, NESA films (registered trademark of PPG, Inc., USA) made of tin oxide (SnO2), ITO films made of indium oxide-tin oxide (In2O3-SnO2), etc., can be used. When manufacturing TN, STN, or VA type liquid crystal elements, two substrates with patterned transparent conductive films are used. On the other hand, when manufacturing IPS or FFS type liquid crystal elements, a substrate with comb-shaped patterned electrodes and a counter substrate without electrodes are used. The liquid crystal alignment agent is applied to the substrate on the electrode formation surface, preferably by offset printing, flexographic printing, spin coating, roll coating, or inkjet printing.

[0096] After applying the liquid crystal alignment agent, preheating (pre-bake) is preferably performed to prevent dripping of the applied liquid crystal alignment agent. The pre-bake temperature is preferably 30 to 200°C, and the pre-bake time is preferably 0.25 to 10 minutes. Subsequently, a firing (post-bake) process is performed to further remove the solvent. The firing temperature (post-bake temperature) at this time is preferably 80 to 250°C, more preferably 80 to 200°C. The post-bake time is preferably 5 to 200 minutes. The film thickness of the film formed in this way is preferably 0.001 to 1 μm.

[0097] <Step 2: Orientation Treatment> When manufacturing TN, STN, IPS, or FFS type liquid crystal elements, a process (alignment treatment) is performed to impart liquid crystal alignment ability to the coating film formed in step 1 above. This imparts the liquid crystal molecule alignment ability to the coating film, making it a liquid crystal alignment film. As an alignment treatment, methods such as rubbing, in which the coating film formed on the substrate is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton, or photo-alignment, in which light is irradiated onto the coating film formed on the substrate to impart liquid crystal alignment ability to the coating film, can be used. On the other hand, when manufacturing vertical alignment (VA) type liquid crystal elements, the coating film formed in step 1 above can be used as is as a liquid crystal alignment film, but an alignment treatment may be applied to the coating film to further enhance its liquid crystal alignment ability. A liquid crystal alignment film suitable for vertical alignment type liquid crystal elements is also suitable for PSA type liquid crystal elements.

[0098] In the photo-alignment process, light irradiation can be performed by methods such as irradiating the coating film after the post-bake process, irradiating the coating film after the pre-bake process but before the post-bake process, or irradiating the coating film while it is being heated in at least one of the pre-bake or post-bake processes. As radiation to irradiate the coating film, for example, ultraviolet light and visible light including light with wavelengths of 150 to 800 nm can be used. Preferably, ultraviolet light including light with wavelengths of 200 to 400 nm is used. If the radiation is polarized, it may be linearly polarized or partially polarized. If the radiation used is linearly polarized or partially polarized, irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. In the case of unpolarized radiation, the irradiation direction should be oblique.

[0099] Examples of light sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, and excimer lasers. The radiation dose to the substrate surface is preferably 400 to 50,000 J / m². 2 And more preferably 1,000 to 20,000 J / m 2The substrate surface may be washed with, for example, water, an organic solvent (e.g., methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.) or a mixture thereof, or the substrate may be heated. As a post-irradiation treatment, it is preferable to heat the substrate to further improve the liquid crystal alignment (heat rearrangement), and the temperature when heating the substrate is preferably 120 to 280°C, and more preferably 150 to 250°C.

[0100] <Step 3: Liquid Crystal Cell Construction> Two substrates with liquid crystal alignment films formed on them as described above are prepared, and a liquid crystal cell is manufactured between the two substrates so that liquid crystal is arranged adjacent to the liquid crystal alignment film. To manufacture the liquid crystal cell, for example, two substrates are placed opposite each other with a gap in between so that the liquid crystal alignment films face each other, the periphery of the two substrates is bonded together with a sealant, and liquid crystal is injected and filled into the cell gap surrounded by the substrate surface and the sealant, sealing the injection hole, or an ODF method can be used. As the sealant, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as spacers can be used. As the liquid crystal, nematic liquid crystal and smectic liquid crystal can be used, and among these, nematic liquid crystal is preferred. In PSA mode, after the construction of the liquid crystal cell, a voltage is applied between the conductive films of the pair of substrates, and the liquid crystal cell is irradiated with light.

[0101] PSA-type liquid crystal elements can be manufactured by a method that includes the following steps. A step of forming a coating film by applying the liquid crystal alignment agent of this disclosure onto the conductive film of each of a pair of substrates having a conductive film. A process for constructing a liquid crystal cell by arranging a pair of substrates coated with a liquid crystal alignment agent so that the coating films face each other with a liquid crystal layer in between. • A process of applying a voltage between conductive films and irradiating a liquid crystal cell with light.

[0102] Specifically, a liquid crystal cell is constructed in the same manner as in steps 1 to 3 above, except that a photopolymerizable monomer is injected or dropped together with the liquid crystal between a pair of substrates having a conductive film. Conventionally known compounds can be used as the photopolymerizable monomer injected or dropped together with the liquid crystal. Preferably, it is a polyfunctional (meth)acrylic monomer.

[0103] In the manufacturing of PSA-type liquid crystal elements, after constructing the liquid crystal cell, a voltage is applied between the conductive films of a pair of substrates, and the liquid crystal cell is irradiated with light. The applied voltage can be, for example, 5 to 50 V DC or AC. As the irradiated light, ultraviolet light and visible light including wavelengths of 150 to 800 nm can be used. Of these, ultraviolet light including wavelengths of 300 to 400 nm is preferred. As the light source for the irradiation light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. can be used. The amount of light irradiated is preferably 1,000 to 200,000 J / m 2 More preferably, 1,000 to 100,000 J / m 2 That is the case.

[0104] For each mode of liquid crystal cell, a polarizing plate is then attached to the outer surface of the liquid crystal cell as needed to form a liquid crystal element. Examples of polarizing plates include a polarizing plate made by sandwiching a polarizing film called an "H film," which is made by stretching and oriented polyvinyl alcohol while absorbing iodine, between cellulose acetate protective films, or a polarizing plate made of the H film itself.

[0105] The liquid crystal elements of this disclosure can be effectively applied to a variety of uses. Specifically, they can be used, for example, in various display devices such as watches, portable game consoles, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, information displays, as well as in dimming devices, phase difference films, and the like.

[0106] According to this disclosure, the following means are provided: [Method 1] A liquid crystal alignment agent containing the polymer (A) and the compound (B) described above. [Method 2] The liquid crystal alignment agent according to [Method 1], wherein the monomer is a diamine. [Method 3] The liquid crystal alignment agent according to [Method 1] or [Method 2], wherein the polymer (A) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. [Method 4] A liquid crystal alignment agent according to any one of [Method 1] to [Method 3], further containing the above-mentioned (C) polymer. [Method 5] The liquid crystal alignment agent according to any one of [Method 1] to [Method 4], wherein the polymer (A) contains structural units derived from aromatic tetracarboxylic dianhydride. [Method 6] The compound (B) is the group F 1 A liquid crystal alignment agent according to any one of [Method 1] to [Method 5], having a total of three or more of these in one molecule. [Means 7] The group F 1 The liquid crystal alignment agent according to any one of [Method 1] to [Method 6], wherein the liquid crystal alignment agent is at least one selected from the group consisting of polymerizable carbon-carbon unsaturated bond-containing groups, cyclic ethers, and protected hydroxyalkylamide groups. [Method 8] The liquid crystal alignment agent according to [Method 4], wherein the (C) polymer contains structural units derived from a tetracarboxylic dianhydride having a cyclobutane ring structure. [Method 9] The (C) polymer is "-NR 4 - represents a base (where R 4 The liquid crystal alignment agent according to [Method 4] or [Method 8], wherein is a leaving group. [Method 10] A liquid crystal alignment film formed using a liquid crystal alignment agent described in any one of [Method 1] to [Method 9]. [Method 11] A method for manufacturing a liquid crystal alignment film, comprising applying a liquid crystal alignment agent described in any one of [Method 1] to [Method 9] onto a substrate, and then subjecting the substrate to a rubbing treatment or light irradiation treatment to impart liquid crystal alignment ability. [Method 12] A liquid crystal element comprising the liquid crystal alignment film described in [Method 10]. [Method 13] A method for manufacturing a liquid crystal element, comprising the steps of: applying a liquid crystal alignment agent described in any one of [Method 1] to [Method 9] to each substrate surface of a pair of substrates, and then applying a rubbing treatment or light irradiation treatment after the application to impart liquid crystal alignment ability and form a liquid crystal alignment film; and arranging the pair of substrates on which the liquid crystal alignment films are formed so that the liquid crystal alignment films face each other with a liquid crystal layer in between to construct a liquid crystal cell. [Examples]

[0107] The present invention will be described in more detail below with reference to examples, but the present invention is not to be interpreted as being limited by the following examples. In the following examples, the required amounts of raw material compounds and polymers were obtained by repeating the synthesis on the synthesis scale shown in the synthesis examples below as needed. In the examples and comparative examples, "parts" and "%" are on a mass basis unless otherwise specified.

[0108] In the following example, the imidization rate of polyimide in the polymer solution was measured by the following method. <Imidification rate of polyimides> A polyimide solution was added to pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. Then it was dissolved in deuterated dimethyl sulfoxide, with tetramethylsilane as the reference material, at room temperature. 1 1H-NMR measurements were performed. 1 The imidization rate [%] was determined from the 1H-NMR spectrum using the following formula (1). Imidization rate [%] = (1 - (A 1 / ( A 2 ×α)))×100 …(1) (In formula (1), A 1 This represents the peak area originating from the proton of the NH group, appearing around a chemical shift of 10 ppm. 2 α represents the peak area derived from other protons. α is the ratio of other protons to one proton in the NH group of the polymer precursor (polyamic acid).

[0109] The abbreviations for the compounds are as follows. In the following, the compound represented by formula (X) may simply be referred to as "compound (X)".

[0110] <Tetracarboxylic acid dianhydride> [ka]

[0111] <Diamine> [ka] [ka] [ka]

[0112] <Additives> [ka]

[0113] <Synthesis of polymers> 1. Synthesis of polyamic acids [Synthesis Example 1] A solution containing 15% by mass of polyamic acid (referred to as polymer (PA-1)) was obtained by dissolving 30 mole parts of compound (TA-2), 40 mole parts of compound (TA-3), and 30 mole parts of compound (TA-4) as tetracarboxylic dianhydrides, and 15 mole parts of compound (DA-9), 35 mole parts of compound (DB-1), and 50 mole parts of compound (DB-5) as diamines in N-methyl-2-pyrrolidone (NMP) and reacting at 40°C for 24 hours.

[0114] [Synthesis Examples 2-17] The same procedure as in Synthesis Example 1 was followed, except that the types and amounts of tetracarboxylic dianhydride and diamine used were changed as shown in Table 1, to obtain polyamic acids (these were designated as polymers (PA-2) to (PA-17)).

[0115] In Table 1, the values ​​for tetracarboxylic dianhydrides (acid dianhydrides 1-3) represent the molar ratio of each compound to 100 moles of the total tetracarboxylic dianhydrides used in the synthesis of each polyamic acid. The values ​​for diamines (diamines 1-4) represent the molar ratio of each compound to 100 moles of the total diamines used in the synthesis of each polyamic acid.

[0116] [Table 1]

[0117] 2. Synthesis of polyimides [Synthesis Example 18] A solution containing 20% ​​by mass of polyamic acid was obtained by dissolving 100 mole parts of compound (TA-1) as a tetracarboxylic dianhydride, and 20 mole parts of compound (DB-3), 40 mole parts of compound (DB-9), and 40 mole parts of compound (DB-13) as diamines in NMP and reacting them at 40°C for 24 hours. Next, NMP was added to the obtained polyamic acid solution, and pyridine and acetic anhydride were added in 1.5 molar equivalents relative to the carboxyl groups of the polyamic acid, and a dehydration and cyclization reaction was carried out at 60°C for 4 hours. After the dehydration and cyclization reaction, the solvent in the system was replaced with fresh NMP, and the solution was further concentrated to obtain a solution containing 20% ​​by mass of polyimide (referred to as polymer (PI-1)) with an imidization rate of approximately 61%.

[0118] [Synthesis Examples 19 and 20] The same procedure as in Synthesis Example 18 was followed, except that the types and amounts of tetracarboxylic dianhydride and diamine used were changed as shown in Table 2, to obtain polyimides (these will be referred to as polymers (PI-2) and (PI-3)).

[0119] In Table 2, the values ​​for tetracarboxylic dianhydrides (acid dianhydrides 1 and 2) represent the molar ratio of each compound to 100 moles of the total amount of tetracarboxylic dianhydrides used in the synthesis of each polyimide. The values ​​for diamines (diamines 1-4) represent the molar ratio of each compound to 100 moles of the total amount of diamines used in the synthesis of each polyimide.

[0120] [Table 2]

[0121] <Preparation and evaluation of liquid crystal alignment agents> [Example 1: Optical FFS type liquid crystal display element] 1. Preparation of liquid crystal alignment agent A solution containing 60 parts by mass of polymer (PA-2) obtained in Synthesis Example 2 and a solution containing 40 parts by mass of polymer (PA-13) obtained in Synthesis Example 13 were mixed. Further, 10 parts by mass of compound (AD-4), NMP, and butyl cellosolve (BC) were added to prepare a solution with a solvent composition of NMP / BC = 80 / 20 (mass ratio) and a solid content concentration of 3.5% by mass. Liquid crystal alignment agent (AL-1) was prepared by filtering this solution through a pore size 0.2 μm filter.

[0122] 2. Manufacturing of FFS-type liquid crystal display elements using the photo-alignment method A glass substrate (referred to as the first substrate) was prepared, on which a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) were laminated in that order on one side, and a glass substrate (referred to as the second substrate) without electrodes was prepared. Next, a liquid crystal alignment agent (AL-1) was applied to the electrode-forming surface of the first substrate and one substrate surface of the second substrate using a spinner, and heated on an 80°C hot plate for 1 minute (pre-bake). After that, it was dried in a 230°C oven with nitrogen purged for 30 minutes (post-bake) to form a coating film with an average thickness of 0.1 μm. The obtained coating film was exposed to 1,000 J / m of ultraviolet light containing linearly polarized 254 nm emission lines using an Hg-Xe lamp. 2The substrate was irradiated from the direction normal to the substrate to perform photoalignment treatment. The irradiation dose was measured using a light meter that measures at a wavelength of 254 nm. Next, the photoaligned coating was heat-treated by heating it in a clean oven at 230°C for 30 minutes to form a liquid crystal alignment film. Next, an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was screen-printed onto the outer edge of one of the pair of substrates on which the liquid crystal alignment film was formed. Then, the substrates were stacked and pressed together so that the projection direction of the polarization axis onto the substrate surface during light irradiation was antiparallel, and the adhesive was heat-cured at 150°C for 1 hour. Next, negative-type liquid crystal (Merck MLC-6608) was filled between the pair of substrates through the liquid crystal injection port, and the liquid crystal injection port was sealed with epoxy adhesive to obtain a liquid crystal cell. Furthermore, to remove the flow orientation during liquid crystal injection, this was heated to 120°C and then slowly cooled to room temperature. Finally, polarizing plates were bonded to both outer surfaces of the substrate in the liquid crystal cell to obtain a liquid crystal display element. The above series of operations was also performed with a post-bake UV irradiation dose of 100-10,000 J / m². 2 By making changes within the specified range, we manufactured three or more liquid crystal display elements with different UV irradiation levels, and the liquid crystal display element with the exposure level that showed the best alignment characteristics (optimal exposure level) was used for the following evaluation.

[0123] 3. Evaluation (1) Evaluation of liquid crystal alignment (evaluation by retardation change rate) The FFS type liquid crystal display elements manufactured by the photoalignment method described in item 2 above are rated at 27,000 cd / m². 2The liquid crystal alignment properties were evaluated by observing the rate of retardation change before and after backlight irradiation after leaving the display elements undisturbed on a high-brightness backlight for 500 hours. First, retardation was measured using an Axoscan from OptoScience Co., Ltd. for the FFS type liquid crystal display elements manufactured by the photo-alignment method described in 2. above, and the rate of retardation change α before and after backlight irradiation was calculated using the following formula (F1). The smaller the rate of change α, the less likely the liquid crystal alignment properties are to deteriorate due to backlight irradiation, and the better the liquid crystal alignment properties are considered to be. A rate of change α of less than 0.5% was judged as "Excellent (◎)", 0.5% or more and less than 1% as "Good (○)", 1% or more and 2% or less as "Acceptable (△)", and greater than 2% as "Poor (×)". α = Δθ / θ1 …(F1) (In equation (F1), Δθ represents the retardation difference before and after irradiation, and θ1 represents the retardation value before irradiation.) As a result, this example received a "Good (○)" rating.

[0124] (2) Evaluation of high-temperature short-term afterimage (DC accumulation and relaxation characteristics) The FFS-type liquid crystal display element manufactured by the photo-alignment method described in 2. above was placed in an environment of 65°C and 1 atmosphere. After driving it with a 30Hz AC square wave (AC) at 100% relative transmittance and setting the brightness difference between any two pixels to 0, the brightness was set to 5,000 cd / m². 2Charge was accumulated by AC-driven only one pixel under backlight illumination. When both pixels were returned to AC-driven mode with a relative transmittance of 25%, a brightness difference was created between the two pixels due to the accumulated charge. As AC-driven mode was continued, the accumulated charge was released, and the brightness difference between the two pixels gradually decreased. The brightness difference after 3 minutes of continuous AC-driven mode with a relative transmittance of 25% was defined as ΔL. As a general trend, charge tends to accumulate more easily in liquid crystal cells at higher temperatures than at room temperature. Therefore, in order to compare the ease of charge accumulation of liquid crystal cells between samples under more severe conditions, the ease of charge accumulation of each liquid crystal element was evaluated by reflecting the initial amount of accumulated charge in a high-temperature environment (short-term afterimage evaluation). The smaller the brightness difference ΔL, the less charge is accumulated, or the more easily the accumulated charge is released, or the less charge is accumulated and the more easily the accumulated charge is released, indicating good afterimage characteristics. If the value obtained by dividing the brightness difference ΔL by the average brightness of the two pixels was less than 1%, it was rated as "Good (○)"; if it was between 1% and 3%, it was rated as "Acceptable (△)"; and if it was 3% or more, it was rated as "Poor (×)". As a result, this example was evaluated as "Good (○)".

[0125] (3) Evaluation of room temperature flicker characteristics The FFS-type liquid crystal display element manufactured by the photo-alignment method described in item 2 above was placed in an environment of 23°C and 1 atmosphere. (5,000 cd / m²) 2 Under backlight illumination, the pixels of an FFS-type liquid crystal display element were driven by applying an AC voltage that resulted in a relative transmittance of 25%. Flicker occurred within the pixels due to the gradual accumulation of charge. This light flicker was detected using an RD-80S (manufactured by Topcon Techno House). The smaller the percentage change in flicker from the initial state after 30 minutes of operation, the less charge accumulated or the easier it was for residual charge to dissipate, indicating a good result. A percentage change in flicker from the initial state after 30 minutes of operation of less than 2% was rated as "Good (○)", 2% to less than 4% was rated as "Acceptable (△)", and 4% or more was rated as "Poor (×)". As a result, this embodiment received an evaluation of "Acceptable (△)".

[0126] (4) Evaluation of membrane strength The liquid crystal alignment agent (AL-1) prepared in step 1 above was filtered through a 1.0 μm filter and then applied to the second substrate by spin coating. Next, it was heated on an 80°C hot plate for 1 minute (pre-bake). After that, it was dried in a 230°C oven with nitrogen purging for 30 minutes (post-bake) to form a coating with an average thickness of 0.1 μm, and the haze value of the coating was measured using a haze meter. Next, the coating was subjected to rubbing five times using a rubbing machine with a roll wrapped in cotton cloth, at a roll rotation speed of 1,000 rpm, a stage movement speed of 3 cm / sec, and a pile insertion length of 0.3 mm. After that, the haze value of the liquid crystal alignment film was measured using a haze meter, and the difference from the haze value before rubbing (haze change value) was calculated. If the haze value of the film before rubbing is Hz1 (%) and the haze value of the film after rubbing is Hz2 (%), the haze change value is expressed by the following formula (F2). Haze change value (%) = Hz2 - Hz1 … (F2) The haze change value in the liquid crystal alignment film was evaluated as follows: less than 0.5% was rated as "Excellent (◎)", 0.5% to less than 0.8% was rated as "Good (○)", 0.8% to less than 1.0% was rated as "Acceptable (△)", and 1.0% or more was rated as "Poor (×)". A haze change value of less than 1.0% indicates sufficiently high film strength and high rubbing resistance, meaning the film has excellent mechanical properties. As a result, this example received an evaluation of "Acceptable (△)".

[0127] [Examples 2-16 and Comparative Examples 1-5] Liquid crystal alignment agents (AL-2) to (AL-16) and (AR-1) to (AR-5) were prepared in the same manner as in Example 1, except that the composition of the liquid crystal alignment agent was changed as shown in Table 3. Furthermore, using the obtained liquid crystal alignment agents, FFS-type liquid crystal display elements were manufactured by photoalignment in the same manner as in Example 1, and the liquid crystal alignment properties, high-temperature short-term afterimage, and room-temperature flicker were evaluated. In addition, the film strength was evaluated for each liquid crystal alignment agent using the same method as in Example 1. The results are shown in Table 3. In Table 3, the values ​​in the columns for polymer components (polymer 1 and polymer 2) and additives (additive 1 and additive 2) represent the solid content ratio (parts by mass) of each compound relative to 100 parts by mass of the total polymer components used in the preparation of the liquid crystal alignment agent.

[0128] [Table 3]

[0129] [Example 17: Loving FFS type liquid crystal display element] 1. Preparation of liquid crystal alignment agent A solution containing 70 parts by mass of polymer (PA-2) obtained in Synthesis Example 2 and a solution containing 30 parts by mass of polymer (PA-15) obtained in Synthesis Example 15 were mixed. Further, 5 parts by mass of compound (AD-3), NMP, and BC were added to prepare a solution with a solvent composition of NMP / BC = 80 / 20 (mass ratio) and a solid content concentration of 4.0% by mass. This solution was filtered through a 0.2 μm pore size filter to prepare the liquid crystal alignment agent (AL-17).

[0130] 2. Manufacturing of FFS-type liquid crystal display elements using the rubbing method A glass substrate was prepared and a coating film was formed in the same manner as in Example 1, except that a liquid crystal alignment agent (AL-17) was used. Next, the surface of the coating film was rubbed using a rubbing machine with a roll wrapped in rayon cloth at a roll rotation speed of 1,000 rpm, a stage movement speed of 3 cm / second, and a pile insertion length of 0.3 mm. After that, ultrasonic cleaning was performed in ultrapure water for 1 minute, and then drying was performed in a 100°C clean oven for 10 minutes to obtain a pair of substrates having a liquid crystal alignment film. Next, for a pair of substrates having a liquid crystal alignment film, an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was screen-printed and applied, leaving a liquid crystal injection port at the edge of the surface where the liquid crystal alignment film was formed. Then, the substrates were stacked and pressed together, and the adhesive was heat-cured at 150°C for 1 hour. Next, negative liquid crystal (Merck MLC-6608) was filled into the gap between the pair of substrates through the liquid crystal injection port, and the liquid crystal injection port was sealed with epoxy adhesive. Furthermore, to eliminate the flow orientation during liquid crystal injection, this was heated to 120°C and then slowly cooled to room temperature to manufacture a liquid crystal cell. When stacking the pair of substrates, the rubbing method of each substrate was made antiparallel. Next, polarizing plates were bonded to both outer surfaces of the substrate in the liquid crystal cell to obtain a liquid crystal display element.

[0131] 3. Evaluation The liquid crystal display elements manufactured in step 2 above were evaluated for liquid crystal alignment, high-temperature short-term afterimage, and room-temperature flicker using the same method as in Example 1. Furthermore, the film strength was evaluated using the liquid crystal alignment agent (AL-17) prepared in step 1 above, using the same method as in Example 1. The results are shown in Table 4.

[0132] [Examples 18-22 and Comparative Example 6] Liquid crystal alignment agents (AL-18) to (AL-22) and (AR-6) were prepared in the same manner as in Example 17, except that the composition of the liquid crystal alignment agent was changed as shown in Table 4. Using the obtained liquid crystal alignment agents, an FFS type liquid crystal display element was manufactured by the rubbing method in the same manner as in Example 17, and the liquid crystal alignment, high-temperature short-term afterimage, and room-temperature flicker were evaluated. In addition, the film strength was evaluated using each liquid crystal alignment agent in the same manner as in Example 1. The results are shown in Table 4. In Table 4, the values ​​in the columns for polymer components (polymer 1 and polymer 2) and additives (additive 1 and additive 2) represent the blending ratio (parts by mass) of each compound in terms of solid content relative to 100 parts by mass of the total amount of polymer components used in the preparation of the liquid crystal alignment agent.

[0133] [Table 4]

[0134] As shown in Tables 3 and 4, polymer (A) contains structural units derived from monomers having a substructure represented by formula (1), and group F 1 Examples 1 to 22, which used a liquid crystal alignment agent containing a compound (B) having two or more polymers in one molecule and no aromatic rings, showed excellent (◎), good (○), or acceptable (△) results in evaluation of liquid crystal alignment, high-temperature short-term afterimage, room-temperature flicker, and film strength, indicating a well-balanced improvement in various properties. In contrast, Comparative Examples 1 and 2, which used a liquid crystal alignment agent without (A) polymers, Comparative Example 3, which used a liquid crystal alignment agent without additives, and Comparative Examples 4 to 6, which used a liquid crystal alignment agent without (B) compounds, showed poor (×) results in one or more of the evaluation results for liquid crystal alignment, high-temperature short-term afterimage, room-temperature flicker, and film strength.

[0135] From the above results, polymer (A) containing structural units derived from monomers having a substructure represented by formula (1), and group F 1 It has been revealed that a liquid crystal alignment agent containing compound (B), which has a total of two or more compounds in one molecule and does not have an aromatic ring, can produce liquid crystal elements with excellent liquid crystal alignment, high-temperature short-term afterimage and room-temperature flicker, as well as liquid crystal alignment films with excellent film strength.

Claims

1. A liquid crystal alignment agent containing the polymer (A) and the compound (B) described below. (A) Polymer: A polymer containing structural units derived from monomers having a substructure represented by the following formula (1). (B) Compound: Group F is at least one selected from the group consisting of polymerizable carbon-carbon unsaturated bond-containing groups, isocyanate groups, protected isocyanate groups, cyclic carbonate groups, groups having a ketene structure, groups having a meldrumic acid structure, cyclic ether groups, cyclic thioether groups, oxazoline groups, protected hydroxyalkylamide groups, protected thiol groups, and protected secondary amino groups. １ A compound having a total of two or more of these elements in one molecule and lacking an aromatic ring (excluding the polymer (A) mentioned above). 【Chemistry 1】 (In formula (1), Ar １ , Ar ２ and R １ are such that Ar １ and Ar ２ are divalent aromatic ring groups, R １ is a hydrogen atom or a monovalent organic group, or Ar １ and Ar ２ are combined with each other to represent a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which Ar １ and Ar ２ are attached, and R １ is a hydrogen atom or a monovalent organic group, or Ar １ and R １ are combined with each other to represent a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which Ar １ and R １ are attached, and Ar ２ is a divalent aromatic ring group. X １ is an alkanediyl group having 1 to 10 carbon atoms, -O-, -S-, -CO-, -CO-O-, -CO-NR ２ -, -NR ２ -CO-O-, -CO-NR ２ -CO-, -NR ２ -CO-NR ３ -, or a divalent group in which some of the methylene groups in an alkanediyl group having 2 to 10 carbon atoms are replaced by -O-, -S-, -CO-, -CO-O-, -CO-NR ２ -, -NR ２ -CO-O-, -CO-NR ２ -CO-, or -NR ２ -CO-NR ３ -. R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group. "*" represents a bond.)

2. The liquid crystal alignment agent according to claim 1, wherein the monomer is a diamine.

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

4. The liquid crystal alignment agent according to claim 1, further comprising the polymer (C) described below. (C) Polymer: A polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, which does not contain structural units derived from monomers having a substructure represented by formula (1).

5. The liquid crystal alignment agent according to claim 1, wherein the polymer (A) comprises structural units derived from aromatic tetracarboxylic dianhydride.

6. The compound (B) has the group F １ The liquid crystal alignment agent according to claim 1, having a total of three or more of these in one molecule.

7. The aforementioned base F １ The liquid crystal alignment agent according to claim 1, wherein the liquid crystal alignment agent is at least one selected from the group consisting of polymerizable carbon-carbon unsaturated bond-containing groups, cyclic ethers, and protected hydroxyalkylamide groups.

8. The liquid crystal alignment agent according to claim 4, wherein the polymer (C) comprises structural units derived from a tetracarboxylic dianhydride having a cyclobutane ring structure.

9. The above (C) polymer is "-NR ４ A group represented by - (where R ４ The liquid crystal alignment agent according to claim 4, wherein is a leaving group.

10. A liquid crystal alignment film formed using the liquid crystal alignment agent described in any one of claims 1 to 9.

11. A method for manufacturing a liquid crystal alignment film, comprising applying a liquid crystal alignment agent according to any one of claims 1 to 9 onto a substrate, and then subjecting it to a rubbing treatment or light irradiation treatment to impart liquid crystal alignment ability.

12. A liquid crystal element comprising the liquid crystal alignment film described in claim 10.

13. A step of forming a liquid crystal alignment film by applying a liquid crystal alignment agent according to any one of claims 1 to 9 to each substrate surface of a pair of substrates, and then applying a rubbing treatment or light irradiation treatment after the application to impart liquid crystal alignment ability, A step of constructing a liquid crystal cell by arranging a pair of substrates on which the liquid crystal alignment films are formed so that the liquid crystal alignment films face each other with a liquid crystal layer in between, A method for manufacturing liquid crystal elements, including

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