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

Abstract

To provide a liquid crystal alignment agent that yields a liquid crystal alignment film with superior liquid crystal alignment properties, electric characteristics, and mechanical characteristics.SOLUTION: A liquid crystal alignment agent includes: a first polymer including a structural unit (I) derived from a diamine with a moiety represented by formula (1) and a structural unit (T) derived from a substituted cyclobutane tetracarboxylic dianhydride, where the content of the structural unit (T) is 75 mol% or more relative to the total amount of a structural unit derived from a tetracarboxylic acid derivative; and a second polymer including a structural unit (II) derived from a diamine with a moiety represented by formula (2).SELECTED DRAWING: None

Description

[Technical field]

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

[0002] A liquid crystal element includes a liquid crystal alignment film having a function of controlling the alignment of liquid crystal molecules in a liquid crystal layer. A liquid crystal alignment film is generally formed on a substrate by applying a liquid crystal alignment agent, which is a polymer dissolved in a solvent, to the substrate surface and preferably by heating.

[0003] In recent years, with the increasing high definition and versatility of liquid crystal elements, liquid crystal alignment films are required to be able to exhibit various properties in a well-balanced manner, such as optical properties such as liquid crystal alignment property and transmittance, electrical properties such as voltage holding ratio, and mechanical properties that do not break down under physical pressure from transportation, tapping, etc. Also, in order to obtain liquid crystal alignment films that can simultaneously exhibit multiple functions such as optical properties, electrical properties, and mechanical properties, liquid crystal alignment agents are prepared by using multiple compounds each having each function and combining these multiple compounds (see, for example, Patent Document 1).

[0004] In recent years, it has been proposed to improve the liquid crystal alignment of a liquid crystal element by incorporating a polyimide obtained by using a diamine having an amide bond or a urea bond into a liquid crystal alignment agent (see, for example, Patent Document 2). Furthermore, it has been proposed to improve the electrical properties of a liquid crystal element by incorporating a polyimide obtained by using a diamine having a nitrogen-containing heterocyclic structure into a liquid crystal alignment agent (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020 / 158818 [Patent Document 2] JP 2018-200439 A [Patent Document 3] International Publication No. 2018 / 062440 Summary of the Invention [Problem to be solved by the invention]

[0006] It is conceivable to achieve both liquid crystal alignment and electrical properties by preparing a liquid crystal alignment agent by combining a polymer obtained by using a diamine (non-basic diamine) having an amide bond or urea bond with a polymer obtained by using a diamine (basic diamine) having an imidazole ring structure or a pyridine ring structure. However, when a liquid crystal alignment agent is prepared by combining these two types of polymers, the liquid crystal alignment film formed by the liquid crystal alignment agent does not have sufficient mechanical properties, and there is room for further improvement. In particular, in recent years, importance has been attached to the mechanical properties of the film in liquid crystal elements, and there is a demand for improving the mechanical properties of the film in addition to the basic properties of liquid crystal alignment and electrical properties.

[0007] The present invention has been made in consideration of the above problems, and has as its main object to provide a liquid crystal aligning agent that can provide a liquid crystal alignment film having excellent mechanical properties while providing a liquid crystal element having excellent liquid crystal alignment properties and electrical properties. [Means for solving the problem]

[0008] According to the present invention, the following means are provided. [1] A liquid crystal aligning agent comprising a first polymer and a second polymer as an imide-based polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, the first polymer having a structural unit (I) derived from a diamine having a partial structure represented by the following formula (1) and a structural unit (T) derived from a compound represented by the following formula (3), the content of the structural unit (T) being 75 mol % or more based on the total amount of structural units derived from a tetracarboxylic acid derivative contained in the first polymer, and the second polymer having a structural unit (II) derived from a diamine having a partial structure represented by the following formula (2), and being different from the first polymer. [ka] (In formula (1), D 1 R is a monovalent organic group having 5 or more carbon atoms. 1 is a single bond, -O- or -NR 3a -It is. 2 is a single bond or -NR 3b -It is. 3a and R 3b are each independently a hydrogen atom or a monovalent organic group having one or more carbon atoms. 4 and R 5 are each independently a substituted or unsubstituted divalent hydrocarbon group or a divalent heterocyclic group. "*" represents a bond.) [ka] (In formula (2), D 2 is a monovalent organic group having 5 or more carbon atoms. d is 1 or 2. When d is 1, R 6 and R 7 are independent of each other, 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, or R 6 and R 7 are combined together to form R 6 and R 7 represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which it is bonded. When d is 2, R 6 and R 7 is R 6 ">C(R 10 )-* 1 ", a trivalent alicyclic group or a trivalent aromatic ring group (provided that "* 1 " represents the bond on the nitrogen side.) R 7 "-C(R 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, or R 6 and R 7 are combined together to form R 6 and R 7 R represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which it is bonded. 10 , R 11 and R12 are each independently a hydrogen atom, a monovalent hydrocarbon group, or a substituent. 8 is a hydrogen atom or an organic group having 1 to 4 carbon atoms. a is 1 or 2. b is 0 or 1. c is 0 or 1, provided that a+b+c=2 is satisfied. R 6 and R 7 are combined together to form R 6 and R 7 represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which it is bonded, a=1, b=1 and c=0. "*" represents a bond. [ka] (In formula (3), R 15 , R 16 , R 17 and R 18 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent group having 1 to 6 carbon atoms and a fluorine atom, or a phenyl group. 15 , R 16 , R 17 and R 18 At least one of is a group other than a hydrogen atom.

[0009] [2] A liquid crystal alignment film formed using the liquid crystal aligning agent according to [1] above. [3] A liquid crystal element comprising the liquid crystal alignment film described in [2] above. Effect of the Invention

[0010] According to the liquid crystal aligning agent of the present invention, it is possible to form a liquid crystal alignment film having excellent mechanical properties while providing a liquid crystal element with excellent liquid crystal alignment properties and electrical properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Liquid crystal alignment agent The liquid crystal aligning agent of the present disclosure contains two or more imide-based polymers selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. These two or more imide-based polymers include a first polymer and a second polymer shown below. First polymer: A polymer having a structural unit (I) derived from a diamine having a partial structure represented by the following formula (1) and a structural unit (T) derived from a compound represented by the following formula (3), the content of the structural unit (T) being 75 mol % or more based on the total amount of structural units derived from a tetracarboxylic acid derivative contained in the first polymer. Second polymer: a polymer having a structural unit (II) derived from a diamine having a partial structure represented by the following formula (2) and different from the first polymer: [ka] (In formula (1), D 1 R is a monovalent organic group having 5 or more carbon atoms. 1 is a single bond, -O- or -NR 3a -It is. 2 is a single bond or -NR 3b -It is. 3a and R 3b are each independently a hydrogen atom or a monovalent organic group having one or more carbon atoms. 4 and R 5 are each independently a substituted or unsubstituted divalent hydrocarbon group or a divalent heterocyclic group. "*" represents a bond.) [ka] (In formula (2), D 2 is a monovalent organic group having 5 or more carbon atoms. d is 1 or 2. When d is 1, R 6 and R 7 are independent of each other, 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, or R 6 and R 7 are combined together to form R 6 and R 7represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which it is bonded. When d is 2, R 6 and R 7 is R 6 ">C(R 10 )-* 1 ", a trivalent alicyclic group, or a trivalent aromatic ring group (provided that "* 1 " represents the bond on the nitrogen side.) R 7 "-C(R 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, or R 6 and R 7 are combined together to form R 6 and R 7 R represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which it is bonded. 10 , R 11 and R 12 are each independently a hydrogen atom, a monovalent hydrocarbon group, or a substituent. 8 is a hydrogen atom or an organic group having 1 to 4 carbon atoms. a is 1 or 2. b is 0 or 1. c is 0 or 1, provided that a+b+c=2 is satisfied. R 6 and R 7 are combined together to form R 6 and R 7 represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which it is bonded, a=1, b=1 and c=0. "*" represents a bond. [ka] (In formula (3), R 15 , R 16 , R 17 and R 18 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent group having 1 to 6 carbon atoms and a fluorine atom, or a phenyl group. 15 , R 16 , R 17 and R 18 At least one of is a group other than a hydrogen atom.

[0012] Hereinafter, each component contained in the liquid crystal aligning agent of the present disclosure and components that are optionally blended as necessary (hereinafter also referred to as "other components") will be described. In this specification, a numerical range described using "~" means that the numerical values ​​described before and after "~" are included as the lower limit and upper limit. Unless otherwise specified, each component may be used alone or in combination of two or more types.

[0013] Here, in this specification, the term "hydrocarbon group" includes chain-shaped hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The term "chain-shaped hydrocarbon group" means a straight-chain hydrocarbon group and a branched hydrocarbon group that do not include a cyclic structure in the main chain and are composed only of a chain structure. However, the chain-shaped hydrocarbon group may be saturated or unsaturated. The term "alicyclic hydrocarbon group" means a hydrocarbon group that includes only an alicyclic hydrocarbon structure as a ring structure and does not include an aromatic ring structure. However, the alicyclic hydrocarbon group does not necessarily have to be composed only of an alicyclic hydrocarbon structure, and also includes those that have a chain structure as a part of it. The term "aromatic hydrocarbon group" means a hydrocarbon group that includes an aromatic ring structure as a ring structure. However, the aromatic hydrocarbon group does not necessarily have to be composed only of an aromatic ring structure, and may include a chain structure or an alicyclic hydrocarbon structure as a part of it. The term "aromatic ring" includes aromatic hydrocarbon rings and aromatic heterocycles. The term "organic group" means an atomic group obtained by removing any hydrogen atom from a compound containing carbon (i.e., an organic compound).

[0014] The "main chain" of a polymer refers to the "trunk" portion of the polymer that is the longest chain of atoms. It is permissible for this "trunk" portion to contain a ring structure. For example, "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain of the polymer. The "side chain" refers to a portion that branches off from the "trunk" of the polymer. The term "tetracarboxylic acid derivative" includes tetracarboxylic acid dianhydrides, tetracarboxylic acid diesters, and tetracarboxylic acid diester dihalides.

[0015] The liquid crystal alignment agent of the present disclosure contains, as a polymer component, two or more kinds of imide-based polymers selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. These two or more kinds of imide-based polymers may contain a polymer (first polymer) having a structural unit (I) and a polymer (second polymer) having a structural unit (II). Therefore, among the structural units constituting the first polymer, the structural units other than the structural unit (I) and among the structural units constituting the second polymer, the structural units other than the structural unit (II) are not particularly limited. For example, the first polymer may have the structural unit (II) together with the structural unit (I). Also, the second polymer may have the structural unit (I) together with the structural unit (II). The first polymer and the second polymer may both have the structural unit (I) and the structural unit (II) as long as they have different monomer compositions.

[0016] Preferred embodiments of the first polymer and the second polymer contained in the liquid crystal aligning agent of the present disclosure include the following [1] and [2]. [1] An embodiment in which the first polymer has the structural unit (I) but does not have the structural unit (II), and the second polymer has the structural unit (II) and the content of the structural unit (I) is a predetermined value or less. [2] An embodiment in which the first polymer has the structural unit (I) and the structural unit (II), the second polymer has the structural unit (II), and the content of the structural unit (I) is a predetermined value or less. The first polymer and the second polymer will be described in detail below.

[0017] <First polymer> The first polymer has a structural unit (I) derived from a diamine having a partial structure represented by the above formula (1) (hereinafter, also referred to as a "first specific diamine"). 1 Examples of the monovalent organic group having 5 or more carbon atoms represented by the formula (I) include a monovalent hydrocarbon group having 5 to 20 carbon atoms and a monovalent leaving group having 5 to 20 carbon atoms. Among these, examples of the monovalent hydrocarbon group having 5 to 20 carbon atoms include a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. 1When is a monovalent hydrocarbon group having 5 to 20 carbon atoms, among the above, an alkyl group having 5 to 10 carbon atoms, a cyclohexyl group, or a phenyl group is preferred.

[0018] D 1 The leaving group represented by the formula (I) is a group which is released by heat, light, etc. and is replaced by a hydrogen atom. 1 The leaving group represented by the formula (I) is preferably a group which is released by heat and is replaced with a hydrogen atom (hereinafter, also referred to as a "thermally detachable group"). Specific examples of the thermally detachable group include a tert-butoxycarbonyl group (Boc group), a benzyloxycarbonyl group, a 1,1-dimethyl-2-haloethyloxycarbonyl group, an allyloxycarbonyl group, a 2-(trimethylsilyl)ethoxycarbonyl group, and a 9-fluorenylmethyloxycarbonyl group (F-moc group).

[0019] D in the above formula (1) 1 From the viewpoint of obtaining a liquid crystal alignment film having excellent mechanical properties while suppressing separation of the first polymer and the second polymer contained in the liquid crystal alignment agent, a thermally detachable group is preferred, and a Boc group is particularly preferred because it has excellent thermal detachability and can reduce the amount of the detached structure remaining in the film.

[0020] R 1 is a single bond, -O- or -NR 3a - and R 2 is a single bond or -NR 3b -It is. 3a or R 3b When R is a monovalent organic group having 1 or more carbon atoms, examples of the monovalent organic group include a monovalent hydrocarbon group having 1 to 12 carbon atoms and a monovalent leaving group. Among these, examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. 3a or R 3b is a monovalent hydrocarbon group having 1 to 20 carbon atoms, R 3a or R 3b R is preferably an alkyl group having 1 to 5 carbon atoms, a cyclohexyl group, or a phenyl group. 3a or R 3bSpecific and preferred examples of the leaving group include D 1 Specific examples and preferred examples of the leaving group include the same groups as those described above. 3a and R 3b Of the above, is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a cyclohexyl group, a phenyl group or a thermally eliminable group, and more preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a Boc group.

[0021] R 1 is a single bond or -NR 3a - is preferred. 2 is preferably a single bond.

[0022] R 4 and R 5 Each of R is a substituted or unsubstituted divalent hydrocarbon group or a divalent heterocyclic group. 4 or R 5 When R is a divalent hydrocarbon group (i.e., an unsubstituted divalent hydrocarbon group), examples of the divalent hydrocarbon group include a chain hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, and an aromatic hydrocarbon group having 6 to 20 carbon atoms. Specific examples of the chain hydrocarbon group having 1 to 20 carbon atoms include a linear or branched saturated chain hydrocarbon group, and a linear or branched unsaturated chain hydrocarbon group. 4 or R 5 When has a substituent (i.e., is a substituted divalent hydrocarbon group), examples of the substituent include a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), a hydroxyl group, a cyano group, a nitro group, an alkoxy group, etc. The expression "substituted or unsubstituted divalent hydrocarbon group" is intended to include a divalent hydrocarbon group and a divalent group obtained by substituting any hydrogen atom in a divalent hydrocarbon group.

[0023] A heterocyclic group is a group formed by removing two hydrogen atoms from the ring portion of a substituted or unsubstituted heterocycle. 4 or R 5When R is a divalent heterocyclic group, the heterocyclic ring contained in the heterocyclic group may be an aliphatic heterocyclic ring or an aromatic heterocyclic ring. 4 or R 5 The divalent heterocyclic group represented by the formula (I) is preferably an aromatic heterocyclic group, more preferably a nitrogen-containing aromatic heterocyclic group. Specific examples of the heterocycle contained in the nitrogen-containing aromatic heterocyclic group include a pyridine ring, a pyridazine ring, and a pyrimidine ring.

[0024] From the viewpoint of obtaining a liquid crystal element having further improved liquid crystal alignment property, R 4 and R 5 one or both of the groups have a substituted or unsubstituted divalent chain hydrocarbon group, and the chain hydrocarbon group is R 1 or R 2 That is, in the above formula (1), R 4 has a substituted or unsubstituted divalent chain hydrocarbon group, R 4 is the chain hydrocarbon group, R 1 or R 5 has a substituted or unsubstituted divalent chain hydrocarbon group, R 5 is the chain hydrocarbon group, R 2 In these cases, the chain hydrocarbon group is preferably an alkanediyl group, and more preferably a linear alkanediyl group. 1 or R 2 The chain hydrocarbon group adjacent to preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 2 to 6 carbon atoms.

[0025] From the viewpoint of further improving the liquid crystal alignment of the liquid crystal element, R 4 and R 5 Both have a substituted or unsubstituted divalent linear hydrocarbon group, R 4 is R 1 is bonded to R via a substituted or unsubstituted divalent linear hydrocarbon group, 5 is R 2 is bonded to the ring through a substituted or unsubstituted divalent linear hydrocarbon group, and1 -CO-ND 1 -R 2 The total number of carbon atoms in the substituted or unsubstituted divalent linear hydrocarbon groups adjacent to both ends of the group represented by "-" is preferably 4 or more.

[0026] The first specific diamine is represented by "-R 1 -CO-ND 1 -R 2 A molecule may have only one group represented by "-R 1 -CO-ND 1 -R 2 The first specific diamine may have two or more groups represented by "-R 1 -CO-ND 1 -R 2 The number of groups represented by "-" is determined by the "-R 1 -CO-ND 1 -R 2 -" is 1 to 4, for example.

[0027] The first polymer may have the partial structure represented by the above formula (1) in the main chain of the polymer or in a side chain. In terms of a high effect of improving liquid crystal alignment properties and electrical properties, it is preferable that the first polymer has the partial structure represented by the above formula (1) in the main chain of the polymer.

[0028] Specific examples of the first specific diamine include compounds represented by the following formulas (1-1) to (1-9), in which "Boc" represents a tert-butoxycarbonyl group (Boc group) (hereinafter the same). [ka]

[0029] The first polymer has a structural unit (T) derived from a compound represented by the above formula (3) (hereinafter also referred to as "substituted cyclobutane tetracarboxylic dianhydride"). The first polymer has a structural unit derived from a substituted cyclobutane tetracarboxylic dianhydride, which is advantageous in that a liquid crystal element exhibiting good liquid crystal alignment properties and electrical characteristics can be obtained by a photoalignment method while increasing the solubility of the first polymer.

[0030] Specific examples of the substituted cyclobutane tetracarboxylic dianhydride include the compounds represented by the following formulas (3-1) to (3-9). Among these, the compound represented by the following formula (3-2) (1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride) is particularly preferred in terms of excellent photoalignment properties. [ka]

[0031] The proportion of the structural unit (T) in the first polymer is 75 mol% or more based on the total amount of structural units derived from the tetracarboxylic acid derivative contained in the first polymer. If the proportion of the structural unit (T) in the first polymer is less than 75 mol%, there is a concern that the pretilt angle will be insufficient when the liquid crystal is given a pretilt angle by a photoalignment method, and the liquid crystal alignment property will be reduced. The proportion of the structural unit (T) in the first polymer is more preferably 80 mol% or more based on the total amount of structural units derived from the tetracarboxylic acid derivative contained in the first polymer, more preferably 90 mol% or more, and even more preferably 95 mol% or more.

[0032] The method for synthesizing the first polymer is not particularly limited. For example, the first polymer can be obtained by a method including a step of polycondensing a tetracarboxylic acid derivative containing a substituted cyclobutanetetracarboxylic dianhydride and a diamine compound containing a first specific diamine.

[0033] (Polyamic acid) When the first polymer is a polyamic acid, the polyamic acid can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound.

[0034] Tetracarboxylic acid dianhydride When the first polymer is a polyamic acid, only the substituted cyclobutane tetracarboxylic dianhydride may be used in synthesizing the first polymer, or a tetracarboxylic dianhydride other than the substituted cyclobutane tetracarboxylic dianhydride (hereinafter also referred to as "other tetracarboxylic dianhydride") may be used. Examples of other tetracarboxylic dianhydrides include aliphatic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides. The term "aliphatic tetracarboxylic dianhydride" includes linear tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides.

[0035] Specific examples of other tetracarboxylic dianhydrides include, as chain tetracarboxylic dianhydrides, 1,2,3,4-butanetetracarboxylic dianhydride, etc.; Alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentane tetracarboxylic dianhydride, cyclohexane tetracarboxylic dianhydride, and the like; Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol bisanhydrotrimate, 4,4'-carbonyldiphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylethertetracarboxylic dianhydride, etc. Also, examples of tetracarboxylic dianhydrides that can be used include tetracarboxylic dianhydrides described in JP-A-2010-97188.

[0036] Diamine compounds The diamine compound used in the synthesis of the first polymer may be the first specific diamine alone, or may be used in combination with a diamine different from the first specific diamine (hereinafter also referred to as "first other diamine"). Examples of the first other diamine include aliphatic diamines, aromatic diamines, and diaminoorganosiloxanes. Aliphatic diamines include chain diamines and alicyclic diamines.

[0037] Specific examples of the first other diamine include, as chain diamines, metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, etc.; as alicyclic diamines, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), etc.; Aromatic diamines include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylether, 4-aminophenyl-4-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,5-bis(4-aminophenoxy)pentane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,6-bis(4-aminophenoxy)hexane, bis[2-(4-aminophenyl)ethyl]hexanedioic acid, 1,4-bis-(4-aminophenyl)-piperazine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane ... bis(4-aminophenyl)hexafluoropropane, 4,4'-(phenylenediisopropylidene)bisaniline, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]dianiline, 4,4'-diaminobenzanilide, 4,4'-diaminostilbene, 1,4 - Main chain diamines such as bis(4-aminophenyl)-piperazine, bis[2-(4-aminophenyl)ethyl]hexanedioic acid, 4,4'-diaminodiphenethyl urea, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, and 4,4'-bis(4-aminophenoxy)biphenyl; Dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy-2,4-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, 3,5-diamino Cholestanyl aminobenzoate, cholestenyl 3,5-diaminobenzoate, lanostannyl 3,5-diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 3,5-diaminobenzoic acid = 5ξ-cholestan-3-yl, the following formula (E-1) [ka] (In formula (E-1), X I and X II are each independently a single bond, -O-, *-COO-, or *-OCO- (wherein "*" indicates a bond to the diaminophenyl group). I R is an alkanediyl group having 1 to 3 carbon atoms. II R is a single bond or an alkanediyl group having 1 to 3 carbon atoms. III is an alkyl group, an alkoxy group, a fluoroalkyl group, or a fluoroalkoxy group having 1 to 20 carbon atoms. a1 is 0 or 1. b1 is an integer of 0 to 3. c1 is an integer of 0 to 2. d1 is 0 or 1, provided that 1≦a1+b1+c1≦3. Side chain type diamines such as compounds represented by the following formula: As the diaminoorganosiloxane, for example, 1,3-bis(3-aminopropyl)-tetramethylsiloxane tetramethyldisiloxane, etc., and the diamines described in JP 2010-97188 A can be used. In addition, as the first other diamine, a diamine having a partial structure represented by the above formula (2) can also be used.

[0038] Examples of the compound represented by formula (E-1) include compounds represented by the following formulas (E-1-1) to (E-1-4). [ka]

[0039] From the viewpoint of obtaining a liquid crystal element having excellent liquid crystal alignment properties, the first polymer preferably contains the structural unit (I) in an amount of 2 mol % or more relative to the structural units derived from the diamine compound contained in the first polymer. The content of the structural unit (I) is more preferably 5 mol % or more, and even more preferably 10 mol or more, relative to the total amount of the structural units derived from the diamine compound contained in the first polymer. The content of the structural unit (I) in the first polymer is preferably 80 mol % or less, more preferably 70 mol % or less, and even more preferably 60 mol % or less, relative to the total amount of the structural units derived from the diamine compound contained in the first polymer.

[0040] The first polymer preferably contains structural units derived from four or more kinds of diamine compounds, including the structural unit (I). By forming the first polymer from four or more kinds of diamine compounds, photodecomposition products generated by light irradiation of a coating film formed by a liquid crystal alignment agent or a liquid crystal cell are suppressed from precipitating in the liquid crystal, and liquid crystal alignment properties (alignment reliability, alignment uniformity) can be further improved. When the first polymer is formed from four or more kinds of diamine compounds, including the structural unit (I), the diamine compound constituting the first polymer preferably contains at least one selected from the group consisting of a diamine having a partial structure represented by the following formula (5) and a diamine having a partial structure represented by the above formula (2), in addition to the first specific diamine. The diamine having a partial structure represented by the following formula (5) is preferred in that it has high sensitivity to light and can improve sensitivity by using it in combination with a compound represented by the above formula (3) (substituted cyclobutane tetracarboxylic dianhydride). [ka] (In formula (5), Ar 3 and Ar 4 are each independently a substituted or unsubstituted phenylene group, a naphthalenediyl group, a biphenylene group, a pyridinediyl group, a pyrimidinediyl group, or a pyrazinediyl group. 1 and Z 2 are, independently of each other, a single bond, -NR 20 -, -O-, -S-, -CO-, * 1 -NH-CO-, * 1 -CO-NH-, * 1 -NH-CO-NH-, * 1 -CO-O- or * 1 -O-CO-. However, Z 1 and Z 2 R cannot be a single bond at the same time. 20 is a hydrogen atom or a monovalent organic group. 1 " is Ar 3 Or Ar 4 It represents a bond with L. 1 -NR 22 -, -O-, -S-, -CO-, * 2-NH-CO-, * 2 -CO-NH-, -NH-CO-NH-, * 2 -CO-O- or * 2 -O-CO-. 22 is a hydrogen atom or a monovalent organic group. 2 " is B 1 B 1 is a divalent aliphatic hydrocarbon group having 1 to 20 carbon atoms. 2 is a divalent aliphatic hydrocarbon group having 3 to 20 carbon atoms. n is an integer of 0 to 3. When n is 2 or 3, multiple B 1 are the same or different, and multiple L 1 are the same or different. "*" represents a bond.)

[0041] In the above formula (5), Z 1 or Z 2 Ga-NR 20 -If R 20 Examples of the monovalent organic group represented by the formula (I) include a monovalent hydrocarbon group having 1 to 10 carbon atoms and a monovalent leaving group. 20 is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally detachable group, and more preferably a thermally detachable group.

[0042] In the case where a photoalignment site (preferably a substituted cyclobutane ring structure) is introduced into the main chain of the first polymer, in order to enhance the photoreactivity of the first polymer, Z 1 and Z 2 is the adjacent aromatic 3 , Ar 4 ) is preferably an electron donating group that increases the electron density of Z 1 and Z 2 At least one of the groups is -O-, -S- or -NR 24 -(R 24 is a hydrogen atom or a monovalent organic group. 24 From the above viewpoint, Z 1 and Z 2 Both are -O-, -S- or -NR 24 More preferably, it is -O- or -NR 24It is even more preferable that R 24 is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally detachable group, and more preferably a thermally detachable group.

[0043] B 1 Examples of the divalent aliphatic hydrocarbon group represented by the formula (I) include a chain hydrocarbon group having 1 to 20 carbon atoms and an alicyclic hydrocarbon group having 3 to 20 carbon atoms. 2 Examples of the divalent aliphatic hydrocarbon group represented by the following formula include a chain hydrocarbon group having 3 to 20 carbon atoms and an alicyclic hydrocarbon group having 3 to 20 carbon atoms.

[0044] B 1 The divalent aliphatic hydrocarbon group represented by the following formula (I) is preferably a divalent linear or branched chain hydrocarbon group having 1 to 10 carbon atoms, more preferably a linear alkanediyl group having 1 to 5 carbon atoms, and even more preferably a linear alkanediyl group having 1 to 3 carbon atoms, in that it can form a liquid crystal alignment film that is highly effective in improving mechanical properties and electrical properties.

[0045] B 2 From the viewpoint of obtaining a liquid crystal element exhibiting good liquid crystal alignment properties, the divalent aliphatic hydrocarbon group represented by the formula (I) is preferably a divalent linear or branched chain hydrocarbon group having 3 to 10 carbon atoms. 2 is more preferably a linear alkanediyl group having 3 to 10 carbon atoms. 2 From the viewpoint of obtaining a liquid crystal element exhibiting good liquid crystal alignment properties, the number of carbon atoms is preferably 8 or less, more preferably 6 or less, and even more preferably 5 or less.

[0046] L 1 Ga-NR 22 -If R 22 Specific and preferred examples of the monovalent organic group represented by the formula (I) are as described above for R 20 Examples of the monovalent organic group represented by the formula L 1 -NR 22 -, -O-, * 2 -NH-CO-, -NH-CO-NH-, * 2-CO-O- or * 2 -O-CO- is preferred, and -NR 22 -- is more preferred. n is preferably 0 to 2, more preferably 0 or 1, and further preferably 0.

[0047] Specific examples of the diamine having the partial structure represented by the above formula (5) include compounds represented by each of the following formulas (5-1) to (5-11). [ka] (In formulas (5-1) to (5-11), k is an integer of 3 to 10.)

[0048] When a diamine having a partial structure represented by the above formula (5) is used in the synthesis of the first polymer, the content of the structural unit derived from the diamine having the partial structure represented by the above formula (5) in the first polymer (hereinafter also referred to as "structural unit (III)") is preferably 1 mol% or more, more preferably 2 mol% or more, and even more preferably 5 mol% or more, based on the total amount of the structural units derived from the diamine compound contained in the first polymer. The content of the structural unit (III) in the first polymer is preferably 90 mol% or less, more preferably 80 mol% or less, based on the total amount of the structural units derived from the diamine compound contained in the first polymer. The compounds represented by the above formulas (5-3), (5-6), (5-7) and (5-9) also correspond to the diamine having the partial structure represented by the above formula (2).

[0049] In the synthesis of the first polymer, when a diamine having a partial structure represented by the above formula (2) is used, the content of the structural unit (II) in the first polymer is preferably 1 mol% or more, more preferably 2 mol% or more, and even more preferably 5 mol% or more, based on the total amount of the structural units derived from the diamine compound contained in the first polymer. The content of the structural unit (II) in the first polymer is preferably 50 mol% or less, more preferably 40 mol% or less, based on the total amount of the structural units derived from the diamine compound contained in the first polymer.

[0050] Synthesis of polyamic acid The polyamic acid can be obtained by reacting the above-mentioned tetracarboxylic dianhydride and diamine compound together with a molecular weight modifier as necessary. The ratio of the tetracarboxylic dianhydride and diamine compound used in the synthesis reaction of the polyamic acid is preferably such that the acid anhydride group of the tetracarboxylic dianhydride is 0.2 to 2 equivalents per equivalent of the amino group of the diamine compound. Examples of the molecular weight modifier include acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride, monoamine compounds such as aniline, cyclohexylamine, and n-butylamine, and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The ratio of the molecular weight modifier used is preferably 20 parts by mass or less per 100 parts by mass of the total of the tetracarboxylic dianhydride and diamine compound used.

[0051] The synthesis reaction of the polyamic acid is preferably carried out in an organic solvent, preferably at a reaction temperature of −20° C. to 150° C., and for a reaction time of 0.1 to 24 hours. Examples of the organic solvent used in the reaction include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Particularly preferred organic solvents are one or more selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenols, or a mixture of one or more of these with other organic solvents (e.g., butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount (a) of the organic solvent used is preferably an amount such that the total amount (b) of the tetracarboxylic dianhydride and the diamine compound is 0.1 to 50% by mass relative to the total amount (a+b) of the reaction solution.

[0052] In this manner, a reaction solution in which polyamic acid is dissolved is obtained. This reaction solution may be used as it is for the preparation of a liquid crystal aligning agent, or the polyamic acid contained in the reaction solution may be isolated and then used for the preparation of a liquid crystal aligning agent.

[0053] (Polyamic acid ester) When the first polymer is a polyamic acid ester, the polyamic acid ester as the first polymer can be obtained, for example, by a method of reacting a polyamic acid having a structural unit (I) with an esterifying agent, a method of reacting a tetracarboxylic acid diester with a diamine compound containing a first specific diamine, or a method of reacting a tetracarboxylic acid diester dihalide with a diamine compound containing a first specific diamine. The polyamic acid ester may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist. The reaction solution in which the polyamic acid ester is dissolved may be used for the preparation of a liquid crystal alignment agent as it is, or the polyamic acid ester contained in the reaction solution may be isolated and then used for the preparation of a liquid crystal alignment agent.

[0054] (Polyimide) When the first polymer is a polyimide, the polyimide as the first polymer can be obtained, for example, by dehydrating and ring-closing a polyamic acid having the structural unit (I) to imidize it. The polyimide preferably has an imidization rate of 20 to 90%, more preferably 30 to 85%. The imidization rate is the ratio of the number of imide ring structures to the total number of amic acid structures and imide ring structures of the polyimide, expressed as a percentage.

[0055] The dehydration ring closure of the polyamic acid is preferably carried out by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating as necessary. In this method, the dehydrating agent may be, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride. The amount of the dehydrating agent used is preferably 0.01 to 20 moles per mole of the amic acid structure of the polyamic acid. The dehydration ring closure catalyst may be, for example, a tertiary amine such as pyridine, collidine, lutidine, or triethylamine. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used.

[0056] Examples of the organic solvent used in the dehydration ring-closing reaction include the organic solvents exemplified as those used in the synthesis of polyamic acid. The reaction temperature in the dehydration ring-closing reaction is preferably 0 to 180°C. The reaction time is preferably 1.0 to 120 hours. The reaction solution containing the polyimide may be used as it is for the preparation of a liquid crystal alignment agent. Also, the polyimide may be isolated from the reaction solution, and the isolated polyimide may be used for the preparation of a liquid crystal alignment agent. The polyimide may also be obtained by dehydration ring-closing of a polyamic acid ester.

[0057] <Second Polymer> The second polymer has a structural unit (II) derived from a diamine having a partial structure represented by the above formula (2) (hereinafter, also referred to as a "second specific diamine"). 2 Specific and preferred examples of the monovalent organic group having 5 or more carbon atoms represented by the formula (1) are 1 Examples of the specific and preferred groups include those shown in the description of 1.

[0058] d is 1 and R 6 or R 7 "-C(R 11 )(R 12 )-" then R 11 or R 12 The monovalent hydrocarbon group represented by the formula (I) is preferably an alkyl group having 1 to 3 carbon atoms.11 or R 12 Examples of the substituent represented by R include an alkoxy group having 1 to 3 carbon atoms, a halogen atom (such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), a primary amino group, a cyano group, a nitro group, a hydroxyl group, and a carboxy group. 11 and R 12 is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a halogen atom or a hydroxyl group, and more preferably a hydrogen atom.

[0059] R 6 or R 7 The divalent alicyclic group represented by the following formula is a group in which two hydrogen atoms have been removed from the ring portion of a substituted or unsubstituted aliphatic ring. Examples of the aliphatic ring include saturated or unsaturated hydrocarbon rings having 3 to 12 carbon atoms. Among these, a cyclopentane ring or a cyclohexane ring is preferred.

[0060] R 6 or R 7 The divalent aromatic ring group represented by is a group in which two hydrogen atoms are removed from the ring portion of a substituted or unsubstituted aromatic ring. The aromatic ring is preferably an aromatic hydrocarbon ring or a nitrogen-containing aromatic heterocycle. Specific examples of these include a benzene ring, a naphthalene ring, an anthracene ring, etc. as the aromatic hydrocarbon ring; and a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an imidazole ring, a benzimidazole ring, a carbazole ring, etc. as the nitrogen-containing aromatic heterocycle.

[0061] R 6 or R 7 When R is a divalent alicyclic group or aromatic ring group and a substituent is bonded to the ring portion, the substituent is preferably an alkyl group having 1 to 3 carbon atoms, or 11 or R 12 The substituent represented by the formula (2) may be the same as the groups exemplified above. 6 Bond (*) and R 7 The bond (*) may be a bond to either of the two primary amino groups of the second specific diamine.

[0062] d is 2 and R 6 ">C(R 10 )-* 1 " (i.e., a group represented by the following formula (6)), a trivalent alicyclic group, or a trivalent aromatic ring group, 6 As a specific example, when d is 1, "-C(R 11 )(R 12 )-" to R 12 and a divalent alicyclic group or a divalent aromatic ring group having one hydrogen atom removed from the ring portion thereof. 7 "-C(R 11 )(R 12 )-", when R is a divalent alicyclic group or a divalent aromatic ring group, 7 Specific examples of the group include the same groups as the specific examples when d is 1. [ka] (In formula (6), R 10 is a hydrogen atom, a monovalent hydrocarbon group, or a substituent. 1 " represents a bond on the nitrogen side. "*" represents a bond.)

[0063] R 6 and R 7 are combined together to form R 6 and R 7 When R represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which it is bonded, the heterocyclic structure is preferably a nitrogen-containing aromatic heterocyclic structure. 6 or R 7 is a divalent aromatic ring group, examples of which include structures having a ring exemplified as the nitrogen-containing aromatic heterocycle.

[0064] R 8 is a hydrogen atom or a monovalent organic group having 1 to 4 carbon atoms. When the partial structure represented by the above formula (2) is condensed with another group in the same molecule by heating during film formation to form a nitrogen-containing aromatic heterocyclic structure containing the nitrogen atom in the above formula (2) in the ring skeleton, R8 is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group, and further preferably a hydrogen atom. From the viewpoint of further increasing the basicity after ring formation by heating during film formation and increasing the reliability of the electrical properties of the liquid crystal element, R 8 is preferably an alkyl group having 1 to 3 carbon atoms.

[0065] If b is 1, R 6 and R 7 At least one of R is preferably a group different from an aromatic ring group. 6 and R 7 When both are aromatic ring groups, the basicity of the partial structure represented by the above formula (2) becomes low, and the effect of improving the reliability of the electrical characteristics of the liquid crystal element tends to be small. Specifically, from the viewpoint of sufficiently improving the effect of improving the reliability of the electrical characteristics of the liquid crystal element, 6 and R 7 When d is 1, R 6 and R 7 At least one of them is "-C(R 11 )(R 12 )-" or R 6 and R 7 are combined together to form R 6 and R 7 It is preferable that R represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which it is bonded. 6 ">C(R 10 )-* 1 " or R 7 "-C(R 11 )(R 12 )-" or both, or R 6 and R 7 are combined together to form R 6 and R 7 It is preferable that R represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which it is bonded.

[0066] The second polymer may have at least a part of the partial structure represented by the above formula (2) in the main chain of the polymer, or may have the partial structure represented by the above formula (2) in a side chain. In the first polymer, the nitrogen atom in the above formula (2) may form a part of the main chain of the polymer, or may be included in the side chain. From the viewpoint of further improving the reliability of the electrical characteristics of the liquid crystal device, it is preferable that the nitrogen atom in the above formula (2) forms a part of the main chain of the polymer or is bonded to a carbon atom that forms a part of the main chain of the polymer.

[0067] From the viewpoint of further enhancing the effect of improving the reliability of the electrical characteristics of a liquid crystal element while maintaining good liquid crystal alignment in the liquid crystal element by incorporating the second polymer, it is preferable that the structural unit (II) is selected from the group consisting of the structural unit (II-1) and the structural unit (II-2) shown below. Structural unit (II-1): A nitrogen atom in the above formula (2) is connected to "-C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 A structural unit derived from a diamine having a partial structure to which " is bonded Structural unit (II-2): A structural unit derived from a diamine having a nitrogen-containing aromatic heterocycle or a partial structure that forms a nitrogen-containing aromatic heterocycle upon heating. Each structural unit will be described below.

[0068] Structural Unit (II-1) By having the second polymer have the structural unit (II-1), a site with high basicity is introduced into the polymer. This can further improve the effect of improving the reliability of the electrical properties of the liquid crystal element. In addition, the partial structure represented by the above formula (2) is more likely to exhibit crosslinking properties, which is preferable in that it can contribute to improving the mechanical properties of the liquid crystal alignment film. The diamine that gives the structural unit (II-1) preferably has a partial structure represented by the following formula (2A). [ka] (In formula (2A), D 2Ais a monovalent thermally labile group. d is 1 or 2. When d is 1, R 6 and R 7 are independent of each other, 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, provided that R 6 and R 7 At least one of them is "-C(R 11 )(R 12 )-". If d is 2, R 6 and R 7 is R 6 ">C(R 10 )-* 1 ", a trivalent alicyclic group, or a trivalent aromatic ring group (provided that "* 1 " represents the bond on the nitrogen side.) R 7 "-C(R 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, provided that R 6 When R is a trivalent alicyclic group or a trivalent aromatic ring group, 7 is "-C(R 11 )(R 12 )-" and R 7 When R is a divalent alicyclic group or a divalent aromatic ring group, 6 is ">C(R 10 )-* 1 R is a trivalent group represented by 11 and R 12 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a substituent. 8 is a hydrogen atom or a monovalent organic group having 1 to 4 carbon atoms. a is 1 or 2. b is 0 or 1. c is 0 or 1, provided that a+b+c=2 is satisfied. When b is 0, R 6 is "-C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 ". "*" represents a bond.)

[0069] Specific examples of the partial structure represented by the above formula (2A) include partial structures represented by each of the following formulas (2A-1) to (2A-8). [ka] (In formulas (2A-1) to (2A-8), "*" represents a bond.)

[0070] R when b is 1 6 and R 7 From the viewpoint of increasing the reliability of the electrical properties of the liquid crystal element by introducing a base moiety, when d is 1, R 6 and R 7 Both are "-C(R 11 )(R 12 )-" is preferred, and when d is 2, R 6 ">C(R 10 )-* 1 " and R 7 "-C(R 11 )(R 12 Specifically, the partial structure represented by the above formula (2A) is preferably the above formulas (2A-3) to (2A-5) among the above formulas (2A-1) to (2A-5), and more preferably the above formula (2A-3).

[0071] A preferred specific example of a diamine that provides the structural unit (II-1), from the viewpoint of providing a liquid crystal element having excellent reliability and further excellent mechanical properties, is a compound represented by the following formula (4). [ka] (In formula (4), Ar 1 and Ar 2 are each independently a divalent aromatic ring group. 1 and X 2 are each independently a divalent chain hydrocarbon group or a divalent group in which some methylene groups in a chain hydrocarbon group are replaced by -O-, -S-, -CO- or -COO-. 1 and Y 2are each independently connected to the nitrogen atom in the above formula (2) by "-C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 " is a group having a partial structure to which X is bonded. 3 is a divalent organic group. r is an integer of 0 to 3. When r is 2 or 3, multiple X 3 , Y 2 are the same or different.)

[0072] In the above formula (4), Ar 1 Or Ar 2 The divalent aromatic ring group represented by R 6 or R 7 When Ar is a divalent aromatic ring group, specific examples thereof include the same groups as those exemplified above. 1 Or Ar 2 is preferably an aromatic hydrocarbon ring group or an aromatic heterocyclic group, and among these, a group having a benzene ring, a naphthalene ring or a pyridine ring is preferable. 1 Or Ar 2 may have a substituent on the ring portion. The substituent is an alkyl group having 1 to 3 carbon atoms, and R 11 or R 12 When is a substituent, examples of the substituent include the same groups as those exemplified above.

[0073] X 1 Or X 2 Examples of the divalent chain hydrocarbon group represented by the formula (I) include an alkanediyl group having 1 to 20 carbon atoms and an alkanediyl group having 1 to 20 carbon atoms. Among these, an alkanediyl group having 1 to 10 carbon atoms is preferred, and a straight-chain alkanediyl group having 1 to 5 carbon atoms is more preferred. X 1 Or X 2 When the chain hydrocarbon group is a divalent group in which some methylene groups are replaced by -O-, -S-, -CO- or -COO-, the chain hydrocarbon group is preferably an alkanediyl group having 2 to 12 carbon atoms, and more preferably a linear alkanediyl group having 2 to 6 carbon atoms.

[0074] X 3Examples of the divalent organic group represented by the formula (1) include a divalent chain hydrocarbon group having 1 to 20 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a divalent group in which some methylene groups in a chain hydrocarbon group having 2 to 20 carbon atoms are replaced with -O-, -S-, -CO- or -COO-, and a hydrocarbon group or a group in which some hydrogen atoms of the divalent group are replaced with a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, and a carboxy group.

[0075] Y 1 Or Y 2 Y preferably has a partial structure represented by the above formula (2A), and specific examples thereof include groups having partial structures represented by each of the above formulas (2A-1) to (2A-8). 1 Or Y 2 Among them, it is preferable that the nitrogen atom in the above formula (2) constitutes a part of the main chain, or has a structure in which the nitrogen atom in the above formula (2) is bonded to a carbon atom constituting a part of the main chain (for example, a partial structure represented by each of the above formulas (2A-1) to (2A-7)). 1 Or Y 2 By having such a structure, the reliability of the liquid crystal element can be further improved. r is preferably 0 to 2, and more preferably 0 or 1.

[0076] Structural Units (II-2) The second polymer has the structural unit (II-2), which is advantageous in that it can improve the reliability of the electrical properties of the liquid crystal element while improving the liquid crystal alignment. The nitrogen-containing aromatic heterocycle of the diamine that gives the structural unit (II-2) includes a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a triazine ring, an imidazole ring, a benzimidazole ring, a carbazole ring, etc., among which an imidazole ring, a pyridine ring, a pyrimidine ring, a benzimidazole ring, or a carbazole ring is preferred. The nitrogen-containing aromatic heterocycle formed by heating is preferably a benzimidazole ring.

[0077] Specific examples of diamines that provide the structural unit (II-2) include diamines having a partial structure in which a nitrogen-containing aromatic heterocyclic group is bonded to the nitrogen atom in the above formula (2) (hereinafter, also referred to as "first heterocyclic diamine"); 6 and R 7 are combined together to form R 6 and R 7 and diamines having a monocyclic or fused ring nitrogen-containing aromatic heterocyclic structure constituted by the nitrogen atom to which the nitrogen atom in the formula (2) is bonded (hereinafter also referred to as "second heterocyclic diamine"); and diamines having a partial structure capable of forming a nitrogen-containing aromatic heterocyclic structure containing the nitrogen atom in the formula (2) in the ring skeleton upon heating (hereinafter also referred to as "third heterocyclic diamine").

[0078] Examples of the first heterocyclic diamine include compounds having partial structures represented by the following formulae (2B-1) to (2B-6). Examples of the second heterocyclic diamine include compounds having partial structures represented by the following formulae (2B-7) to (2B-10). Examples of the third heterocyclic diamine include compounds having partial structures represented by the following formulae (2B-11) to (2B-14). [ka] (In formulas (2B-1) to (2B-14), "*" represents a bond.)

[0079] Specific examples of the second specific diamine include compounds represented by the following formulas (2-1) to (2-30). [ka] [ka] [ka] [ka]

[0080] The second specific diamine has a nitrogen atom in the above formula (2) with “—C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 " is bonded to the diamine, and more preferably to the diamine represented by the above formula (4). Among the above formulas (2-1) to (2-30), the compounds represented by the above formulas (2-1) to (2-10) and (2-29) are diamines that provide the structural unit (II-1). The compounds represented by the above formulas (2-11) to (2-23) and (2-30) are diamines that provide the structural unit (II-2).

[0081] The second polymer is preferably a polymer having a structural unit (II) in which the nitrogen atom in the above formula (2) is linked to “—C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 In particular, it is preferable that the nitrogen atom in the above formula (2) contains a structural unit derived from a diamine having a partial structure in which "-C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 " is bonded to a carbon atom that constitutes a part of the main chain, and the nitrogen atom in the above formula (2) constitutes a part of the main chain, or the nitrogen atom in the above formula (2) contains a diamine having a partial structure bonded to a carbon atom that constitutes a part of the main chain.

[0082] In the second polymer, the content of the structural unit (II) is preferably 2 mol % or more, more preferably 5 mol % or more, and even more preferably 10 mol % or more, based on the total amount of the structural units derived from the diamine compound contained in the second polymer, from the viewpoint of obtaining a sufficient effect of improving the reliability of the electrical properties of the liquid crystal element. In addition, when various properties such as the voltage holding ratio and liquid crystal alignment are adjusted by introducing a structural unit different from the structural unit (II) into the polymer, the content of the structural unit (II) in the second polymer is, for example, 95 mol % or less, based on the total amount of the structural units derived from the diamine compound contained in the second polymer.

[0083] The synthesis method of the second polymer is also not particularly limited. The second polymer can be obtained by a method including a step of polycondensing a tetracarboxylic acid derivative and a diamine compound. For example, when obtaining a polyamic acid as the second polymer, it can be obtained by reacting a tetracarboxylic acid dianhydride exemplified as a tetracarboxylic acid dianhydride that can be used in the synthesis of the first polymer with a diamine compound containing a second specific diamine. In this case, as the diamine compound, only the second specific diamine may be used, or a diamine compound different from the second specific diamine (hereinafter also referred to as "second other diamine") may be used in combination. As the second other diamine, the same as the first specific diamine and the first other diamine exemplified in the explanation of the first polymer can be mentioned. For details of the synthesis method of the second polymer, the explanation of the first polymer is applied.

[0084] However, from the viewpoint of promoting phase separation between the first polymer and the second polymer in the liquid crystal alignment film, the content of the structural unit (I) in the second polymer is preferably equal to or less than the content of the structural unit (I) in the first polymer. Specifically, the content of the structural unit (I) in the second polymer is preferably 20 mol % or less, more preferably 15 mol % or less, even more preferably 10 mol % or less, and even more preferably 5 mol % or less, based on the total amount of the structural units derived from the diamine compound contained in the second polymer.

[0085] From the viewpoint of further enhancing the effect of improving the electrical properties, the second other diamine is 3 -CO-NH-* 3 OR* 3 -NH-CO-NH-* 3 Diamines that can be introduced into the polymer main chain (except for "* 3 " represents a bond to an aliphatic hydrocarbon group or an aromatic hydrocarbon group. 5 -N(R 13 )-Ar 6 -* is a diamine capable of introducing a partial structure represented by the formula (Ar 5 and Ar 6 are each independently a divalent aromatic ring group, R 13 is a hydrogen atom or a monovalent hydrocarbon group. "*" represents a bond.) and diamines capable of introducing a nitrogen-containing aromatic condensed ring structure into the polymer main chain (hereinafter also referred to as "diamine (D2)").

[0086] * 3 -CO-NH-* 3 OR* 3 -NH-CO-NH-* 3 Examples of diamines that can be introduced into the polymer main chain include compounds represented by the following formula. [ka]

[0087] *-Ar 5 -N(R 13 )-Ar 6 Examples of diamines capable of introducing a partial structure represented by -* into the polymer main chain include compounds represented by the following formula. [ka]

[0088] Examples of diamines capable of introducing a nitrogen-containing aromatic condensed ring structure into the polymer main chain include compounds represented by the following formula. [ka]

[0089] When diamine (D2) is used in the synthesis of the second polymer, the content of the structural units derived from diamine (D2) in the second polymer is preferably 2 mol % or more, more preferably 5 mol % or more, based on the total amount of the structural units derived from the diamine compound contained in the second polymer. The content of the structural units derived from diamine (D2) in the second polymer is preferably 80 mol % or less, more preferably 70 mol % or less, based on the total amount of the structural units derived from the diamine compound contained in the second polymer.

[0090] In order to obtain a liquid crystal alignment film having excellent mechanical properties while being able to fully exhibit the effect of improving the liquid crystal alignment property by the incorporation of the first polymer and the effect of improving the reliability of the electrical properties by the incorporation of the second polymer, D in the above formula (1) is 1 and D in the above formula (2) 2 is preferably a monovalent thermally detachable group. 1 and D in the above formula (2) 2 When is a monovalent thermally detachable group, it is considered that separation of polymer chains is suppressed, and thus mechanical properties can be improved. The amount of the structure that is detached by applying heat remaining in the film can be reduced, and the deterioration of the mechanical properties and performance of the film can be suppressed. 1 and D in the above formula (2) 2 Among these, a Boc group is preferred.

[0091] The solution viscosity of each of the first polymer and the second polymer is preferably 10 to 800 mPa·s, and more preferably 15 to 500 mPa·s, when the polymer is made into a 10% by mass solution. The solution viscosity (mPa·s) is a value measured at 25°C using an E-type rotational viscometer for a 10% by mass polymer solution prepared using a good solvent for the first polymer and the second polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0092] The first polymer and the second polymer each have a polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of preferably 1,000 to 500,000, more preferably 2,000 to 300,000. The molecular weight distribution (Mw / Mn), which is expressed as the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC, is preferably 7 or less, more preferably 5 or less.

[0093] The content ratio of the first polymer in the liquid crystal alignment agent is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, relative to 100 parts by mass of the total amount of the first polymer and the second polymer contained in the liquid crystal alignment agent. The content ratio of the first polymer is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less, relative to 100 parts by mass of the total amount of the first polymer and the second polymer contained in the liquid crystal alignment agent. In other words, the content ratio of the second polymer is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and even more preferably 50 parts by mass or more, relative to 100 parts by mass of the total amount of the first polymer and the second polymer contained in the liquid crystal alignment agent. The content ratio of the second polymer is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 85 parts by mass or less, relative to 100 parts by mass of the total amount of the first polymer and the second polymer contained in the liquid crystal alignment agent. By setting the content ratio of the first polymer and the second polymer in the liquid crystal aligning agent within the above range, it is possible to obtain a liquid crystal device having a well-balanced improved liquid crystal alignment property and electrical characteristics.

[0094] From the viewpoint of obtaining a liquid crystal element having a well-balanced improvement in liquid crystal alignment properties and electrical properties, the total content ratio of the first polymer and the second polymer in the liquid crystal alignment agent is preferably 50 mass % or more, more preferably 60 mass % or more, and even more preferably 70 mass % or more, based on the total amount of solids contained in the liquid crystal alignment agent (i.e., the total mass of components other than the solvent of the liquid crystal alignment agent).

[0095] <Other ingredients> Examples of other components that can be incorporated into the liquid crystal aligning agent of the present disclosure include a polymer different from the first polymer and the second polymer (hereinafter, also referred to as "other polymers"), a crosslinking agent, and the like.

[0096] Other polymers The other polymer may be a polymer having neither the structural unit (I) nor the structural unit (II), and its main skeleton is not particularly limited. Examples of the other polymer include polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamideimide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, and addition polymer. From the viewpoint of obtaining a liquid crystal element having high reliability in various performances such as electrical characteristics and liquid crystal alignment, the other polymer is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyurea, polyamideimide, polyorganosiloxane, and addition polymer, and more preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer.

[0097] The content of the other polymer in the liquid crystal alignment agent of the present disclosure is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, based on the total amount of the first polymer, the second polymer, and the other polymer.

[0098] Crosslinking agent Examples of the crosslinking agent include a group having a polymerizable carbon-carbon bond, a cyclic ether group, a cyclic thioether group, an isocyanate group, a protected isocyanate group, a methylol group, a protected methylol group, a hydroxyalkylamide group, a protected hydroxyalkylamide group, a cyclic carbonate group, and a group "-CR 31 =CR 32 -R 33 -" (but R 31 R is a monovalent organic group that is eliminated by reaction with an amino group. 32 is a hydrogen atom or an alkyl group, R33 is an electron-withdrawing group.) and compounds having at least one crosslinkable group selected from the group consisting of a silanol group, an amino group, a protected amino group, and an alkoxysilyl group.

[0099] Among the above crosslinkable groups, groups having a polymerizable carbon-carbon bond include (meth)acryloyl group, maleimide group, alkenyl group, vinylphenyl group, vinyl ether group, 3-methylenetetrahydrofuran-2(3H)-one-5-yl group, etc. As the crosslinking agent, among the above, a compound having a functional group capable of reacting with an amino group or a carboxy group can be preferably used, and among them, a compound having a total of two or more of at least one selected from the group consisting of a cyclic ether group, a hydroxyalkylamide group, a protected hydroxyalkylamide group, a methylol group, a protected methylol group, a protected isocyanate group, an amino group, a protected amino group, and an alkoxysilyl group in one molecule can be preferably used.

[0100] From the viewpoint of improving the liquid crystal alignment property, voltage retention property, and film strength of the liquid crystal element in a well-balanced manner, the number of crosslinkable groups that the crosslinking agent has in one molecule is preferably 2 to 12, and more preferably 2 to 10. From the viewpoint of ensuring good storage stability, the molecular weight of the crosslinking agent is preferably 2,000 or less, more preferably 1,000 or less, and even more preferably 800 or less.

[0101] Specific examples of the crosslinking agent include compounds having a cyclic ether group, such as N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether, N,N-diglycidyl-aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine, cyclic siloxanes having two or more glycidyl groups, and epoxidation products of pentaerythritol tetraallyl ether with hydrogen peroxide; As the compound having a hydroxyalkylamide group or a protected hydroxyalkylamide group, compounds represented by the following formulae (c-1) to (c-3) and the like are included: As the compound having a methylol group or a protected methylol group, the compounds represented by the following formulae (c-4) to (c-9) and the like are mentioned: As the compound having a protected isocyanate group, the compounds represented by the following formulae (c-10) to (c-14) and the like are used: As the compound having an amino group or a protected amino group, the compounds represented by each of the following formulae (c-15) to (c-18) and the like are included: Examples of compounds having an alkoxysilyl group include glycidyloxypropyltrimethoxysilane, glycidyloxypropyltriethoxysilane, and 3-aminopropyltrimethoxysilane. [ka] [ka] (In formula (c-8), Ac is an acetyl group.) [ka] (In formula (c-10) and formula (c-11), R 34 is a tert-butoxy group.) [ka]

[0102] When a crosslinking agent is blended into the liquid crystal alignment agent of the present disclosure, the content ratio of the crosslinking agent is preferably 0.5 parts by mass or more relative to 100 parts by mass of the total amount of the polymer components contained in the liquid crystal alignment agent (i.e., the total amount of the first polymer, the second polymer, and other polymers) from the viewpoint of improving the liquid crystal alignment property and the voltage retention property. The content ratio of the crosslinking agent is more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, relative to 100 parts by mass of the total amount of the polymer components. In addition, from the viewpoint of ensuring the liquid crystal alignment property and voltage retention property of the liquid crystal element, as well as the storage stability of the liquid crystal alignment agent, the content ratio of the crosslinking agent is preferably 30 parts by mass or less, and more preferably 20 parts by mass or less, relative to 100 parts by mass of the total amount of the polymer components.

[0103] ·solvent The liquid crystal aligning agent of the present disclosure is prepared as a liquid composition in which the first polymer, the second polymer, and other components used as necessary are preferably dispersed or dissolved in a suitable solvent.

[0104] As the solvent, an organic solvent is preferably used.Specific examples thereof include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, phenol, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, 1-hexanol, 2-hexanol, propane-1,2-diol, 3-methoxy-1-butanol, ethylene glycol monomethyl ether, methyl lactate, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, ethyl propionate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, and ethylene glycol-i-propyl ether. Examples of the solvent include ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate, propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentanone, cyclohexanone, etc. As the solvent, one type can be used alone or two or more types can be mixed and used.

[0105] Other components contained in the liquid crystal alignment agent include, in addition to the above, for example, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, etc. The blending ratio of other components can be appropriately selected according to each compound within a range that does not impair the effects of the present disclosure.

[0106] The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc. The solid content concentration of the liquid crystal alignment agent is preferably in the range of 1 to 10 mass %. If the solid content concentration is 1 mass % or more, it is preferable in that the thickness of the coating film can be sufficiently ensured and a liquid crystal alignment film showing better liquid crystal alignment properties can be obtained. On the other hand, if the solid content concentration is 10 mass % or less, the coating film can be made to have an appropriate thickness, and a liquid crystal alignment film showing good liquid crystal alignment properties can be easily obtained, and the viscosity of the liquid crystal alignment agent becomes appropriate, tending to improve the coatability.

[0107] <Liquid crystal alignment film and its manufacturing method> The liquid crystal alignment film of the present disclosure is formed by the liquid crystal alignment agent prepared as described above. The liquid crystal alignment film can be produced by a method including the following coating film formation process. The liquid crystal alignment film of the present disclosure may be provided with liquid crystal alignment ability by performing liquid crystal alignment treatment on the organic film obtained by the coating film formation process by the following alignment treatment process.

[0108] ·Coating film formation process In producing a liquid crystal alignment film, first, a liquid crystal alignment agent is applied onto a substrate, and then the applied surface is preferably heated to form a coating film on the substrate. As the substrate, for example, a transparent substrate made of glass such as float glass or soda glass, or plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or poly(alicyclic olefin) can be used.

[0109] The method of applying the liquid crystal alignment agent to the substrate is not particularly limited. The liquid crystal alignment agent can be applied to the substrate by, for example, a spin coat method, a printing method (for example, an offset printing method, a flexographic printing method, etc.), an inkjet method, a slit coat method, a bar coater method, an extrusion die method, a direct gravure coater method, a chamber doctor coater method, an offset gravure coater method, an impregnation coater method, an MB coater method, etc.

[0110] After the liquid crystal alignment agent is applied, preheating (prebaking) is preferably performed for the purpose of preventing dripping of the applied liquid crystal alignment agent. The prebaking temperature is preferably 30 to 200° C., and the prebaking time is preferably 0.25 to 10 minutes. Thereafter, the solvent is completely removed, and a baking (postbaking) step is performed, if necessary, for the purpose of thermally imidizing the amic acid structure present in the polymer. The baking temperature (postbaking temperature) at this time is preferably 80 to 280° C., more preferably 80 to 250° C. The postbaking time is preferably 5 to 200 minutes. The thickness of the film formed is preferably 0.001 to 1 μm.

[0111] ·Orientation process In the alignment treatment step, the liquid crystal alignment agent is applied onto the substrate, and after the application, a heat treatment is preferably performed, and then a rubbing treatment or a light irradiation treatment is preferably performed to impart liquid crystal alignment ability. In the rubbing treatment, 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, to impart liquid crystal alignment ability to the coating film. In the light alignment treatment, the coating film formed on the substrate is irradiated with light to impart liquid crystal alignment ability to the coating film.

[0112] In the photo-alignment treatment, the light irradiation can be performed by a method of irradiating the coating film after the post-bake step, a method of irradiating the coating film after the pre-bake step but before the post-bake step, or a method of irradiating the coating film during heating in at least one of the pre-bake step and the post-bake step. For example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm can be used as the radiation to be irradiated to the coating film. Preferably, ultraviolet light containing light with a wavelength of 200 to 400 nm is used. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, the irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When the radiation is non-polarized, the irradiation direction is an oblique direction.

[0113] Examples of the light source used include 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. The radiation dose is preferably 400 to 50,000 J / m 2 and more preferably 1,000 to 20,000 J / m 2 After the light irradiation for imparting the alignment ability, the surface of the substrate 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.

[0114] Liquid crystal element The liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The driving method of the liquid crystal in the liquid crystal element is not particularly limited, and can be applied to various modes such as 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, PSA (Polymer Sustained Alignment) type, etc. The liquid crystal element can be manufactured, for example, by a method including the above-mentioned coating film formation step and alignment treatment step, and the following cell construction step.

[0115] The substrates used in the coating film formation process vary depending on the desired operation mode. For example, when manufacturing a TN-type, STN-type, or VA-type liquid crystal element, two substrates with patterned transparent conductive films are used. When manufacturing an IPS-type or FFS-type liquid crystal element, a substrate with comb-shaped patterned electrodes and an opposing substrate with no electrodes are used. Examples of the transparent conductive film that can be used include a NESA film (registered trademark of PPG, USA) made of tin oxide (SnO2), and an ITO film made of indium oxide-tin oxide (In2O3-SnO2).

[0116] When manufacturing a TN-type, STN-type, IPS-type or FFS-type liquid crystal element, a treatment (alignment treatment) is carried out to impart liquid crystal alignment ability to the coating film obtained by the coating film formation process. This imparts the alignment ability of liquid crystal molecules to the coating film, forming a liquid crystal alignment film. On the other hand, when manufacturing a vertical alignment (VA) type liquid crystal element, the coating film obtained by the coating film formation process can be used as a liquid crystal alignment film as it is. In addition, in order to further enhance the liquid crystal alignment ability, the coating film may be subjected to an alignment treatment. A liquid crystal alignment film suitable for a vertical alignment type liquid crystal element is also suitable for a PSA type liquid crystal element.

[0117] Cell construction process Two substrates on which the liquid crystal alignment film is formed as described above are prepared, and a liquid crystal cell is manufactured so that the liquid crystal is disposed adjacent to the liquid crystal alignment film between the two substrates. For example, the liquid crystal cell can be manufactured by disposing two substrates facing each other with a gap therebetween so that the liquid crystal alignment film faces each other, bonding the peripheries of the two substrates with a sealant, injecting liquid crystal into the cell gap surrounded by the substrate surfaces and the sealant, and sealing the injection hole, or by a method using the ODF method. For example, an epoxy resin containing a hardener and aluminum oxide spheres as a spacer can be used as the sealant. For the liquid crystal, nematic liquid crystal and smectic liquid crystal can be mentioned, and among them, nematic liquid crystal is preferred. In the PSA mode, after the liquid crystal cell is constructed, a process is performed in which the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of a pair of substrates.

[0118] The PSA type liquid crystal element can be produced by a method including the following steps. A process of applying the liquid crystal aligning agent of the present disclosure onto each conductive film of a pair of substrates having a conductive film to form a coating film. The process of constructing a liquid crystal cell by placing a pair of substrates coated with a liquid crystal alignment agent so that the coating films face each other, sandwiching the liquid crystal layer between them. A process in which light is irradiated onto the liquid crystal cell while a voltage is applied between the conductive films.

[0119] 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. As the photopolymerizable monomer to be injected or dropped together with the liquid crystal, a conventionally known compound can be used. Preferably, it is a polyfunctional (meth)acrylic monomer.

[0120] In the manufacture of a PSA type liquid crystal element, after the liquid crystal cell is constructed, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of a pair of substrates. The voltage to be applied can be, for example, 5 to 50 V DC or AC. As the light to be irradiated, for example, ultraviolet light containing light with a wavelength of 150 to 800 nm and visible light can be used. Of these, ultraviolet light containing light with a wavelength 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 light irradiation dose is preferably 1,000 to 200,000 J / m 2 and more preferably 1,000 to 100,000 J / m 2 It is.

[0121] For each mode of liquid crystal cell, a polarizing plate is then attached to the outer surface of the liquid crystal cell as necessary to form a liquid crystal element. Examples of the polarizing plate include a polarizing film called an "H film" made by absorbing iodine while stretching and aligning polyvinyl alcohol, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

[0122] Either positive or negative type liquid crystal may be used. When negative type liquid crystal is used in IPS type and FFS type liquid crystal elements, it is preferable because the transmission loss at the upper part of the electrode can be reduced and the contrast can be improved. Examples of liquid crystal include nematic liquid crystal and smectic liquid crystal, and among them, nematic liquid crystal is preferable.

[0123] The liquid crystal element of the present disclosure can be effectively applied to various applications, specifically, for example, it can be used as various display devices such as clocks, portable game machines, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays, as well as light control devices, retardation films, and the like.

[0124] According to the present disclosure described above, the following means are provided. [Means 1] A liquid crystal aligning agent comprising a first polymer and a second polymer as imide-based polymers selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, the first polymer having a structural unit (I) derived from a diamine having a partial structure represented by the above formula (1) and a structural unit (T) derived from a compound represented by the above formula (3), the content of the structural unit (T) being 75 mol % or more based on the total amount of structural units derived from a tetracarboxylic acid derivative contained in the first polymer, and the second polymer having a structural unit (II) derived from a diamine having a partial structure represented by the above formula (2), and being different from the first polymer. [Means 2] D in the above formula (1) 1 and D in the above formula (2) 2 The liquid crystal aligning agent according to [means 1], wherein is a monovalent thermally detachable group. [Means 3] R in the above formula (1) 4 and R 5 one or both of the groups have a substituted or unsubstituted divalent chain hydrocarbon group, and the chain hydrocarbon group is R 1 or R 2 The liquid crystal aligning agent according to [Means 1] or [Means 2], wherein the liquid crystal aligning agent is bonded to [Measure 4] The liquid crystal aligning agent according to any one of [Measure 1] to [Measure 3], wherein the first polymer has a partial structure represented by the above formula (1) in its main chain. [Means 5] The liquid crystal aligning agent according to any one of [Means 1] to [Means 4], wherein the first polymer has structural units derived from four or more kinds of diamine compounds including the structural unit (I). [Means 6] The liquid crystal aligning agent according to any one of [Means 1] to [Means 5], wherein the nitrogen atom in the above formula (2) constitutes a part of the main chain of the second polymer, or the nitrogen atom in the above formula (2) is bonded to a carbon atom constituting a part of the main chain of the second polymer. [Means 7] The second polymer has, as the structural unit (II), a nitrogen atom in the above formula (2) joined with "-C(R 11 )(R 12 )-" or ">C(R 10 )-*1 The liquid crystal aligning agent according to any one of [Means 1] to [Means 6], comprising a structural unit (II-1) derived from a diamine having a partial structure to which " is bonded." [Means 8] The liquid crystal aligning agent according to [Means 7], wherein the structural unit (II-1) is a structural unit derived from a diamine represented by the above formula (4). [Measure 9] The liquid crystal aligning agent according to any one of [Measure 1] to [Measure 8], further comprising a crosslinking agent. [Measure 10] A liquid crystal alignment film formed by using the liquid crystal aligning agent according to any one of [Measure 1] to [Measure 9]. [Means 11] A liquid crystal element comprising the liquid crystal alignment film according to [Means 10]. EXAMPLES

[0125] The present invention will be described in more detail below with reference to examples. However, the present invention should not be construed as being limited to the following examples.

[0126] In the following examples, the imidization rate of polyimide in a polymer solution was measured by the following method. [Imidization rate of polyimide] The polyimide solution was poured into pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. It was then dissolved in deuterated dimethyl sulfoxide and measured at room temperature using tetramethylsilane as a standard substance. 1 H-NMR measurement was performed. 1 The imidization rate [%] was calculated from the H-NMR spectrum using the following formula (1). Imidization rate [%] = (1-(A 1 / (A 2 ×α)))×100 …(1) (In formula (1), A 1 is the peak area due to the proton of the NH group that appears at a chemical shift of around 10 ppm. 2 is the peak area due to other protons. α is the ratio of the number of other protons to one proton of the NH group in the polymer precursor (polyamic acid).

[0127] In the following examples, the synthesis on a synthesis scale shown in the following synthesis examples was repeated as necessary to ensure the necessary amounts of raw material compounds and polymers. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified.

[0128] The abbreviations of the compounds are as follows: In the following, the compound represented by formula (X) may be simply referred to as "compound (X)".

[0129] (Tetracarboxylic acid dianhydride) [ka]

[0130] (Diamine compounds) The first specific diamine [ka]

[0131] Second specific diamine [ka]

[0132] Other diamines [ka] [ka] [ka]

[0133] (Additives) [ka]

[0134] <Polymer synthesis> 1. Synthesis of polyamic acid [Synthesis Example 1] 100 parts by mole of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (compound (b-1)) as a tetracarboxylic dianhydride, 20 parts by mole of compound (DA-1), 10 parts by mole of compound (a-1), 20 parts by mole of compound (a-4), and 50 parts by mole of compound (a-7) as diamine compounds were dissolved in N-methyl-2-pyrrolidone (NMP) and reacted at 40° C. for 6 hours to obtain a solution containing 15% by mass of polyamic acid (referred to as polymer (PAA-1)).

[0135] [Synthesis Examples 2-55] Polyamic acids (polymers (PAA-2) to (PAA-48) and polymers (pa-1) to (pa-7)) were obtained by the same operation as in Synthesis Example 1, except that the types and amounts of the tetracarboxylic dianhydrides and diamine compounds used were changed as shown in Table 1. In Table 1, the values ​​of the tetracarboxylic dianhydrides (acid dianhydrides 1 to 3) represent the ratio (molar ratio) of each compound to 100 parts by mole of the total amount of the tetracarboxylic dianhydrides used in the synthesis of each polyamic acid. The values ​​of the diamine compounds (diamines 1 to 4) represent the ratio (molar ratio) of each compound to 100 parts by mole of the total amount of the diamine compounds used in the synthesis of each polyamic acid.

[0136] [Table 1]

[0137] 2. Synthesis of Polyimide [Synthesis Example 56] The same operation as in Synthesis Example 1 was carried out to obtain a solution containing 15% by mass of polymer (PAA-1). Next, NMP was added to the obtained polyamic acid solution to obtain a solution with a polyamic acid concentration of 10% by mass, and pyridine and acetic anhydride were added to perform a dehydration ring-closing reaction at 60° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by mass of polyimide with an imidization rate of about 80% (this is referred to as polymer (PI-1)).

[0138] [Synthesis Example 57] The same procedure as in Synthesis Example 56 was carried out except that the amounts of pyridine and acetic anhydride added were 0.6 times the amounts used in Synthesis Example 56, to obtain a solution containing 15 mass% of polyimide with an imidization rate of approximately 60% (referred to as polymer (PI-2)).

[0139] [Synthesis Example 58] The same operation as in Synthesis Example 4 was carried out to obtain a solution containing 15% by mass of polymer (PAA-4). Next, NMP was added to the obtained polyamic acid solution to obtain a solution with a polyamic acid concentration of 10% by mass, and pyridine and acetic anhydride were added to perform a dehydration ring-closing reaction at 60° C. for 4 hours. At that time, the amount of pyridine and acetic anhydride added was adjusted to be 0.6 times the amount used in Synthesis Example 56. After the dehydration ring-closing reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by mass of polyimide with an imidization rate of about 60% (this is referred to as polymer (PI-3)).

[0140] [Synthesis Example 59] The same operation as in Synthesis Example 11 was carried out to obtain a solution containing 15% by mass of polymer (PAA-11). Next, NMP was added to the obtained polyamic acid solution to obtain a solution with a polyamic acid concentration of 10% by mass, and pyridine and acetic anhydride were added to perform a dehydration ring-closing reaction at 60° C. for 4 hours. At that time, the amount of pyridine and acetic anhydride added was adjusted to be 0.6 times the amount used in Synthesis Example 56. After the dehydration ring-closing reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by mass of polyimide with an imidization rate of about 50% (this is referred to as polymer (PI-4)).

[0141] [Synthesis Example 60] The same operation as in Synthesis Example 12 was carried out to obtain a solution containing 15% by mass of polymer (PAA-12). Next, NMP was added to the obtained polyamic acid solution to obtain a solution with a polyamic acid concentration of 10% by mass, and pyridine and acetic anhydride were added to perform a dehydration ring-closing reaction at 60° C. for 4 hours. At that time, the amount of pyridine and acetic anhydride added was adjusted to be 0.6 times the amount used in Synthesis Example 56. After the dehydration ring-closing reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by mass of polyimide with an imidization rate of about 50% (this is referred to as polymer (PI-5)).

[0142] [Synthesis Example 61] As tetracarboxylic dianhydrides, 70 mol parts of compound (b-1) and 30 mol parts of compound (b-2), and as diamine compounds, 20 mol parts of compound (DA-1), 20 mol parts of compound (DA-11) and 60 mol parts of compound (a-7) were dissolved in NMP, and the reaction was carried out at 40 ° C. for 6 hours to obtain a solution containing 15 mass% of polyamic acid. Next, NMP was added to the obtained polyamic acid solution to obtain a solution with a polyamic acid concentration of 10 mass%, and pyridine and acetic anhydride were added to carry out a dehydration ring-closing reaction at 60 ° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 15 mass% of polyimide (this is polymer (pii-1)) with an imidization rate of about 80%.

[0143] <Preparation and Evaluation of Liquid Crystal Alignment Agent> [Example 1: Optical FFS type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent 30 parts by mass of the solution containing the polymer (PAA-1) obtained in Synthesis Example 1 as solid content, 70 parts by mass of the solution containing the polymer (PAA-14) obtained in Synthesis Example 17 as solid content, 2 parts by mass of the compound (N-1), and 1 part by mass of the compound (N-3) were mixed, and diluted with NMP, N-ethyl-2-pyrrolidone (NEP), gamma butyrolactone (BL), and butyl cellosolve (BC) to obtain a solution with a solvent composition of NMP / NEP / BL / BC=15 / 45 / 20 / 20 (mass ratio) and a solid content concentration of 3.5% by mass. The liquid crystal alignment agent (AL-1) was prepared by filtering this solution through a filter with a pore size of 0.2 μm.

[0144] 2. Fabrication of FFS-type LCD elements using the photoalignment method A glass substrate (first substrate) having a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) laminated in this order on one side thereof, and a glass substrate (second substrate) without an electrode were prepared. Next, a liquid crystal alignment agent (AL-1) was applied to each of the electrode-forming surface of the first substrate and one substrate surface of the second substrate using a spinner, and heated (pre-baked) on a hot plate at 80°C for 1 minute. Thereafter, the substrate was dried (post-baked) for 30 minutes in an oven at 230°C with the interior replaced with nitrogen, forming a coating film with an average thickness of 0.1 μm. The obtained coating film was irradiated with 5,000 J / m2 of linearly polarized ultraviolet light including a 254 nm emission line using an Hg-Xe lamp. 2 The coating film was irradiated with light from the normal direction of the substrate to perform a photo-alignment treatment. The amount of irradiation was measured using an actinometer that measures at a wavelength of 254 nm. Next, the coating film that had been subjected to the photo-alignment treatment was heated in a clean oven at 230°C for 30 minutes to perform a heat treatment, thereby forming a liquid crystal alignment film. Next, an epoxy resin adhesive containing aluminum oxide spheres with a diameter of 3.5 μm was applied by screen printing to the outer edge of the surface having the liquid crystal alignment film on one of the pair of substrates on which the liquid crystal alignment film was formed. After that, the substrates were overlapped and pressed together so that the projection directions of the polarization axes on the substrate surface during light irradiation were antiparallel, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was filled between the pair of substrates through the liquid crystal injection port, and the liquid crystal injection port was sealed with an epoxy adhesive to obtain a liquid crystal cell. Furthermore, in order to remove the flow alignment during liquid crystal injection, the liquid crystal cell was heated at 120°C and then slowly cooled to room temperature. The above series of operations was also performed with a UV irradiation dose of 100 to 10,000 J / m after post-baking. 2 Three or more liquid crystal cells with different UV exposure doses were manufactured by changing the exposure dose within the range of , and the liquid crystal cell with the exposure dose that showed the best alignment characteristics (optimum exposure dose) was used for the following evaluation of liquid crystal alignment, alignment uniformity, and VHR reliability.

[0145] 3. Evaluation of liquid crystal alignment by retardation change rate The liquid crystal cell manufactured in 2 above was placed in a 27,000cd / m 2 The cell was left standing for 500 hours on a high-brightness backlight, and the liquid crystal alignment was evaluated based on the retardation change rate before and after backlight irradiation. First, the retardation of the liquid crystal cell manufactured in 2 above was measured using Axoscan manufactured by Optoscience, and the retardation change rate α before and after backlight irradiation was calculated using the following formula (z-1). It can be said that the smaller the change rate α, the more stable the liquid crystal alignment and the better the reliability. A change rate α of 1% or less was evaluated as "good (○)", a change rate α of more than 1% and less than 2% was evaluated as "fair (△)", and a change rate α of more than 2% was evaluated as "poor (×)". α=Δθ / θ1 …(z-1) (In formula (z-1), Δθ represents the retardation difference before and after irradiation, and θ1 represents the retardation value before irradiation.) As a result, the liquid crystal alignment (alignment stability) of this example was evaluated as "good (◯)".

[0146] 4. Evaluation of alignment uniformity Using the liquid crystal cell manufactured in 2. above, the retardation was measured at any 20 points on one pixel surface using Axoscan manufactured by Optoscience, and the standard deviation was calculated. The retardation standard deviation was evaluated as "good (○)" when it was 0.05 or less, "fair (△)" when it was greater than 0.05 and less than 0.07, and "poor (×)" when it was greater than 0.07. As a result, the alignment uniformity of this example was evaluated as "good (○)".

[0147] 5. Evaluation of VHR reliability The liquid crystal cell manufactured in 2 above was evaluated for reliability in terms of voltage holding ratio. The evaluation was performed as follows. First, a voltage of 1V was applied to the liquid crystal cell for 60 microseconds, and then the voltage holding ratio (VHR1) was measured 1670 milliseconds after the voltage was removed. Next, the liquid crystal cell was irradiated with CCFL (backlight) at 60°C for one week, and then left to stand at room temperature and cooled naturally to room temperature. After cooling, a voltage of 1V was applied to the liquid crystal cell for 60 microseconds, and then the voltage holding ratio (VHR2) was measured 1670 milliseconds after the voltage was removed. The measurement device used was a VHR measurement device "VHR-1" manufactured by Toyo Corporation. The rate of change in VHR (ΔVHR) at this time was calculated from the difference between VHR1 and VHR2 (ΔVHR=VHR1-VHR2), and the VHR reliability was evaluated based on ΔVHR. If ΔVHR was less than 15%, it was judged as "good (○)", if it was between 15% and 20%, it was judged as "fair (△)", and if it was more than 20%, it was judged as "poor (×)". As a result, the VHR reliability of this example was rated as "fair (△)".

[0148] 6. Film strength (adhesion to substrate) evaluation The liquid crystal alignment agent (AL-1) prepared in 1 above was applied to a glass substrate using a spinner, pre-baked for 2 minutes on a hot plate at 80°C, and then heated (post-baked) for 30 minutes in an oven at 230°C with the interior replaced with nitrogen, forming a coating film with an average thickness of 0.10 μm. By repeating the same operation, two glass substrates with coating films were produced. An ODF sealant (S-WB42, manufactured by Sekisui Chemical Co., Ltd.) was applied to the coating film of one of the glass substrates with the coating film formed thereon so that the width of the sealant was 1 mm, and the other glass substrate was laminated so that the coating film and the ODF sealant were in contact with each other. After that, a metal halide lamp was used to apply 30,000 J / m 2 After irradiating the film with light (converted to 365 nm), the film was heated in an oven at 120°C for 1 hour. After heating, the adhesion strength was measured using a compression and tensile tester (model number: SDWS-0201-100SL) manufactured by Imada Seisakusho, to evaluate the adhesion of the film to the substrate. The evaluation was performed when the adhesion strength was 200 N / cm 2 If it is more than 100N / cm, it is considered to be "Good (○)". 2More than 200N / cm 2 If it is less than 100N / cm, it is "Fair (△)". 2 If the adhesion was less than 212 N / cm, it was rated as "poor (x)". 2 The result was rated as "good (○)."

[0149] 7. Evaluation of film strength (rubbing resistance) The liquid crystal alignment agent (AL-1) prepared in 1 above was applied onto a glass substrate using a spinner, and heated (pre-baked) on a hot plate at 110°C for 3 minutes. After that, the substrate was dried (post-baked) for 30 minutes in an oven at 230°C with nitrogen substitution inside, forming a coating film with an average thickness of 0.08μm. The haze value of the coating film was measured using a hazemeter. Next, the coating film was rubbed five times with a rubbing machine having a roll wrapped with cotton cloth at a roll rotation speed of 1000rpm, a stage moving speed of 3cm / sec, and a pile pressing length of 0.3mm. After that, the haze value of the liquid crystal alignment film was measured using a hazemeter, and the difference from the haze value before the rubbing treatment (haze change value) was calculated. When the haze value of the film before the rubbing treatment is Hz1 (%) and the haze value of the film after the rubbing treatment is Hz2 (%), the haze change value is expressed by the following formula (z-2). Haze change value (%) = Hz2 - Hz1 ... (z-2) A haze change value of less than 0.5 in the liquid crystal alignment film was evaluated as "good (○)", a haze change value of 0.5 to 1.5 was evaluated as "fair (△)", and a haze change value of more than 1.5 was evaluated as "poor (×)". If the haze change value is 1.5 or less (more preferably less than 0.5), it can be said that the film strength is sufficiently high and the rubbing resistance is high, that is, the mechanical properties of the film are good. As a result, this example was evaluated as "good (○)".

[0150] [Examples 2 to 70 and Comparative Examples 1 to 8] A liquid crystal alignment agent was prepared in the same manner as in Example 1, except that the composition of the liquid crystal alignment agent was changed as shown in Tables 2 and 3. In addition, using the obtained liquid crystal alignment agent, an FFS-type liquid crystal cell was produced by a photoalignment method in the same manner as in Example 1, and various evaluations were performed. The results are shown in Tables 2 and 3. The numerical values ​​in the mass ratio column indicate the blending ratio (parts by mass) of the solid content of each compound (polymer, additive) relative to 100 parts by mass of the total amount of the polymer components used in the preparation of the liquid crystal alignment agent.

[0151] [Table 2]

[0152] [Table 3]

[0153] As shown in Tables 2 and 3, in Examples 1 to 70, which used a liquid crystal alignment agent containing an imide-based polymer (first polymer) having a structural unit (I) derived from a diamine having a partial structure represented by the above formula (1) and a structural unit (T) derived from a compound represented by the above formula (3) in a predetermined proportion or more, and an imide-based polymer (second polymer) having a structural unit (II) derived from a diamine having a partial structure represented by the above formula (2), the liquid crystal alignment properties (alignment stability and alignment uniformity), VHR reliability, and film strength (film adhesion and rubbing resistance) were improved in a balanced manner compared to Comparative Examples 1 to 8, which used a liquid crystal alignment agent that did not contain at least one of the first polymer and the second polymer.

[0154] Among them, in Examples 2 to 6, 9 to 21, 24 to 32, 41, and 50 to 51 among Examples 1 to 70, the liquid crystal alignment, VHR reliability, and film strength were evaluated as "good (○)", indicating that the electrical properties (VHR reliability) and film strength could be improved while maintaining the liquid crystal alignment. This is considered to be because the first polymer containing the structural unit (I) was a polymer obtained using four or more types of diamine compounds, which enabled the liquid crystal alignment and film strength to be further improved, and because the second polymer containing the structural unit (II) had a strongly basic nitrogen-containing group protected by a leaving group, which enabled the electrical properties to be improved while maintaining the liquid crystal alignment.

[0155] [Example 71: Rubbed FFS type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent 40 parts by mass of the solution containing the polymer (PAA-1) obtained in Synthesis Example 1 as solid content, 60 parts by mass of the solution containing the polymer (PAA-14) obtained in Synthesis Example 17 as solid content, 2 parts by mass of the compound (N-1), and 1 part by mass of the compound (N-3) were mixed and diluted with NMP, NEP, and butyl cellosolve (BC) to obtain a solution with a solvent composition of NMP / NEP / BC=20 / 40 / 40 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-79).

[0156] 2. Fabrication of FFS-type LCD elements using the rubbing method A glass substrate (first substrate) having a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) laminated in this order on one side thereof, and a glass substrate (second substrate) having no electrode were prepared. Next, a liquid crystal alignment agent (AL-79) was applied to the electrode-formed surface of the first substrate and one side of the second substrate, respectively, using a spinner, and heated (pre-baked) on a hot plate at 110°C for 3 minutes. Then, the substrate was dried (post-baked) for 30 minutes in an oven at 230°C, the inside of which was replaced with nitrogen, to form a coating film with an average thickness of 0.08 μm. Next, the coating film surface was subjected to rubbing treatment using a rubbing machine having a roll wrapped with rayon cloth, with a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / sec, and a pile indentation length of 0.3 mm. Then, ultrasonic cleaning was performed in ultrapure water for 1 minute, and then drying was performed in a clean oven at 100°C for 10 minutes to obtain a pair of substrates having a liquid crystal alignment film. Next, a pair of substrates having a liquid crystal alignment film was screen-printed with an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 3.5 μm, leaving a liquid crystal injection port at the edge of the surface on which the liquid crystal alignment film was formed. The substrates were then superimposed and pressed together, and the adhesive was thermally cured at 150°C for 1 hour. Next, a negative liquid crystal (MLC-6608, manufactured by Merck) was filled into the gap between the pair of substrates through the liquid crystal injection port, and the liquid crystal injection port was then sealed with an epoxy adhesive. Furthermore, in order to remove flow alignment during liquid crystal injection, the substrate was heated at 120°C and then slowly cooled to room temperature to produce a liquid crystal cell. When the pair of substrates were superimposed, the rubbing method of each substrate was set to be antiparallel.

[0157] 3. Evaluation The liquid crystal alignment property of the liquid crystal cell manufactured in the above 2 was evaluated in the same manner as in Example 1. In addition, the film strength (film adhesion and rubbing resistance) was evaluated using a liquid crystal alignment agent (AL-79) in the same manner as in Example 1. The evaluation results are shown in Table 3.

[0158] [Examples 72 to 82 and Comparative Examples 9 to 12] A liquid crystal alignment agent was prepared in the same manner as in Example 71, except that the composition of the liquid crystal alignment agent was changed as shown in Table 4. In addition, using the obtained liquid crystal alignment agent, an FFS-type liquid crystal cell was manufactured by a rubbing method in the same manner as in Example 71, and various evaluations were performed. The results are shown in Table 4. In Table 4, the numerical values ​​in the mass ratio column represent the blending ratio (parts by mass) of the solid content of each compound (polymer, additive) relative to 100 parts by mass of the total amount of the polymer components used in the preparation of the liquid crystal alignment agent.

[0159] [Table 4]

[0160] As shown in Table 4, in Examples 71 to 82, which used a liquid crystal alignment agent containing an imide-based polymer (first polymer) having a structural unit (I) derived from a diamine having a partial structure represented by the above formula (1) and a structural unit (T) derived from a compound represented by the above formula (3) in a predetermined proportion or more, and an imide-based polymer (second polymer) having a structural unit (II) derived from a diamine having a partial structure represented by the above formula (2), the liquid crystal alignment properties (alignment stability and alignment uniformity), VHR reliability, and film strength (film adhesion and rubbing resistance) were improved in a balanced manner compared to Comparative Examples 9 to 12, which used a liquid crystal alignment agent that did not contain at least one of the first polymer and the second polymer.

[0161] From the above results, it has become clear that a liquid crystal alignment agent containing an imide-based polymer having a structural unit (I) derived from a diamine having a partial structure represented by the above formula (1) and having a predetermined proportion or more of a structural unit (T) derived from a compound represented by the above formula (3), and an imide-based polymer having a structural unit (II) derived from a diamine having a partial structure represented by the above formula (2) can obtain a liquid crystal element having excellent liquid crystal alignment properties (alignment stability, alignment uniformity) and VHR reliability, and can form a liquid crystal alignment film having excellent mechanical properties.

Claims

1. The imide-based polymer includes a first polymer and a second polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, the first polymer has a structural unit (I) derived from a diamine having a partial structure represented by the following formula (1) and a structural unit (T) derived from a compound represented by the following formula (3), and a content ratio of the structural unit (T) is 75 mol % or more with respect to a total amount of structural units derived from a tetracarboxylic acid derivative contained in the first polymer, The second polymer has a structural unit (II) derived from a diamine having a partial structure represented by the following formula (2), and is a polymer different from the first polymer: Liquid crystal alignment agent. 【Chemistry 1】 (In formula (1), D １ R is a monovalent organic group having 5 or more carbon atoms. １ is a single bond, -O- or -NR ３ａ - is. ２ is a single bond or -NR ３ｂ - is. ３ａ and R ３ｂ are each independently a hydrogen atom or a monovalent organic group having one or more carbon atoms. ４ and R ５ are each independently a substituted or unsubstituted divalent hydrocarbon group or a divalent heterocyclic group. "*" represents a bond.) 【Chemistry 2】 (In formula (2), D ２ is a monovalent organic group having 5 or more carbon atoms. d is 1 or 2. When d is 1, R ６ and R ７ are each independently "-C(R １１ ) (R １２ )-", a divalent alicyclic group or a divalent aromatic ring group, or R ６ and R ７ are combined together to form R ６ and R ７ represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which R is bonded. ６ and R ７ is R ６ ">C(R １０ )-* １ ", a trivalent alicyclic group, or a trivalent aromatic ring group (provided that "* １ " represents a bond on the nitrogen side.), R ７ "-C(R １１ ) (R １２ )-", a divalent alicyclic group or a divalent aromatic ring group, or R ６ and R ７ are combined together to form R ６ and R ７ R represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which it is bonded. １０ , R １１ and R １２ are each independently a hydrogen atom, a monovalent hydrocarbon group, or a substituent. ８ is a hydrogen atom or an organic group having 1 to 4 carbon atoms. a is 1 or 2. b is 0 or 1. c is 0 or 1. However, a+b+c=2 is satisfied. R ６ and R ７ are combined together to form R ６ and R ７ represents a monocyclic or condensed heterocyclic structure formed together with the nitrogen atom to which it is bonded, a=1, b=1 and c=0. "*" represents a bond. 【Chemistry 3】 (In formula (3), R １５ , R １６ , R １７ and R １８ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent group having 1 to 6 carbon atoms and a fluorine atom, or a phenyl group. １５ , R １６ , R １７ and R １８ At least one of is a group other than a hydrogen atom.

2. D in the above formula (1) １ and D in the above formula (2) ２ The liquid crystal aligning agent according to claim 1 , wherein is a monovalent thermally detachable group.

3. R in the above formula (1) ４ and R ５ one or both of the groups have a substituted or unsubstituted divalent chain hydrocarbon group, and the chain hydrocarbon group is R １ Or R ２ The liquid crystal aligning agent according to claim 1 , wherein the liquid crystal aligning agent is bonded to

4. The liquid crystal aligning agent according to claim 1 , wherein the first polymer has a partial structure represented by the above formula (1) in a main chain.

5. The liquid crystal aligning agent according to claim 1 , wherein the first polymer has structural units derived from four or more kinds of diamine compounds including the structural unit (I).

6. The liquid crystal alignment agent according to claim 1, wherein the nitrogen atom in the formula (2) constitutes a part of the main chain of the second polymer, or the nitrogen atom in the formula (2) is bonded to a carbon atom that constitutes a part of the main chain of the second polymer.

7. The second polymer has, as the structural unit (II), a nitrogen atom in the formula (2) having “—C(R １１ ) (R １２ )-" or ">C(R １０ )-* １ The liquid crystal aligning agent according to claim 1, comprising a structural unit (II-1) derived from a diamine having a partial structure to which " is bonded."

8. The liquid crystal aligning agent according to claim 7, wherein the structural unit (II-1) is a structural unit derived from a diamine represented by the following formula (4): 【Chemistry 4】 (In formula (4), Ar １ and Ar ２ are each independently a divalent aromatic ring group. １ and X ２ are each independently a divalent chain hydrocarbon group or a divalent group in which some methylene groups in a chain hydrocarbon group are replaced by -O-, -S-, -CO- or -COO-. １ and Y ２ are each independently connected to the nitrogen atom in the above formula (2) by "-C(R １１ ) (R １２ )-" or ">C(R １０ )-* １ " is a group having a partial structure to which X is bonded. ３ is a divalent organic group. r is an integer of 0 to 3. When r is 2 or 3, multiple X ３ , multiple Y ２ are the same or different.)

9. The liquid crystal aligning agent according to claim 1 , further comprising a crosslinking agent.

10. A liquid crystal alignment film formed by using the liquid crystal aligning agent according to any one of claims 1 to 9.

11. A liquid crystal element comprising the liquid crystal alignment film according to claim 10.

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