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

Abstract

The present invention provides a liquid crystal aligning agent that can form a liquid crystal alignment film having excellent mechanical properties, and can provide a liquid crystal element that exhibits good liquid crystal alignment properties, a high voltage holding ratio, and excellent reliability. [Solution] A liquid crystal aligning agent contains polymer (A), which is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and is obtained using two or more tetracarboxylic acid derivatives including a compound represented by formula (1), and satisfies at least one of requirements 1 and 2. Requirement 1: Further, polymer (B) different from polymer (A) is contained. Requirement 2: Two or more types of polymer (A) are contained. In formula (1), Y 1 and Y 2 are each independently a tetravalent organic group. 1 is a divalent organic group. TIFF0007758236000037.tif24168

Description

[Technical Field]

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

[0002] Liquid crystal devices are widely used in televisions, mobile devices, various monitors, and the like. In liquid crystal devices, the alignment of liquid crystal molecules in a liquid crystal cell is generally controlled by a liquid crystal alignment film, which is an organic film formed on a substrate. Conventional methods for obtaining an organic film with liquid crystal alignment control power include rubbing an organic film formed using a polymer composition, obliquely vapor-depositing silicon oxide, forming a monomolecular film having a long-chain alkyl group, and irradiating a photosensitive organic film with light (photoalignment method). Of these, the rubbing method is commonly used because it is simple and provides good alignment of liquid crystal molecules. Furthermore, the photoalignment method can impart uniform liquid crystal alignment to a photosensitive organic film while suppressing the generation of static electricity and dust, and also enables precise control of the liquid crystal alignment direction, and therefore has been extensively studied in recent years.

[0003] In recent years, liquid crystal elements have been applied to a wide range of devices and applications, from large-screen liquid crystal televisions to small display devices such as smartphones and tablet PCs, and further improvements in performance are being demanded of liquid crystal elements. Against this background, further improvements in the display quality of liquid crystal elements have become more important than ever, and various liquid crystal alignment agents have been proposed to achieve this (see, for example, Patent Documents 1 and 2).

[0004] Patent Documents 1 and 2 disclose a liquid crystal alignment agent containing a polyimide precursor or polyimide obtained using a diamine of a specific structure composed of a (thio)urea bond, a spacer moiety, a linking group, and two aminophenyl structures, with the aim of obtaining a liquid crystal alignment film that is less likely to be scraped or scratched on the film surface during rubbing treatment and has excellent rubbing resistance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2010 / 053128 [Patent Document 2] International Publication No. 2011 / 136375 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional liquid crystal aligning agents capable of forming coating films with high rubbing resistance and good mechanical properties tend to result in a low voltage holding ratio of liquid crystal elements, and to have insufficient liquid crystal alignment properties and reliability. In order to meet the recent demand for even higher performance, liquid crystal aligning agents are required to provide liquid crystal alignment films with good mechanical properties and to provide liquid crystal elements with a good balance of liquid crystal alignment properties, voltage holding ratio, and reliability.

[0007] The present invention has been made in view of the above circumstances, and one object of the present invention is to provide a liquid crystal alignment agent that can form a liquid crystal alignment film having excellent mechanical properties, and can obtain a liquid crystal element that has good liquid crystal alignment properties and voltage retention properties, and is highly reliable. [Means for solving the problem]

[0008] According to the present invention, there are provided the following liquid crystal aligning agent, liquid crystal alignment film and method for producing the same, liquid crystal device, and compound.

[0009] [1] A liquid crystal aligning agent comprising a polymer (A) obtained using two or more tetracarboxylic acid derivatives including at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, the polymer (A) being at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and containing a compound represented by the following formula (1), and satisfying at least one of the following requirements 1 and 2: Requirement 1: The composition further contains a polymer (B) different from the polymer (A). Requirement 2: The polymer (A) contains two or more kinds. [ka] (In formula (1), Y 1 and Y 2 are each independently a tetravalent organic group. 1 is a divalent organic group.

[0010] [2] The liquid crystal aligning agent according to [1], wherein the polymer (B) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. [3] At least one of the polymer (A) and the polymer (B) is 1 -N(R 1 )-* 1 The partial structure represented by (where R 1 is a hydrogen atom or a monovalent organic group. 1 " represents a bond to an atom other than a hydrogen atom.) and a nitrogen-containing heterocycle. The liquid crystal aligning agent according to [1] or [2], comprising a polymer containing a structural unit derived from a diamine having at least one selected from the group consisting of a nitrogen-containing heterocycle. [4] At least one of the polymer (A) and the polymer (B) is -N(R 2 )- (where R 2 is a monovalent group which is eliminated by heat or light.) The liquid crystal aligning agent according to any one of [1] to [3], containing a polymer having the following. [5] The polymer (A) is -N(R 2 The liquid crystal aligning agent according to [4], containing a polymer having a partial structure represented by the formula: [6] Y in the above formula (1) 1 and Y 2 The liquid crystal aligning agent according to any one of [1] to [5], wherein the following have the same structure: [7] Y in the above formula (1) 1 and Y 2 The liquid crystal aligning agent according to any one of [1] to [6], wherein has an alicyclic structure. [8] Y in the above formula (1) 1 and Y 2 The liquid crystal aligning agent according to [7], wherein the compound has a cyclobutane ring structure. [9] The liquid crystal aligning agent according to any one of [1] to [8], wherein the polymer (A) is a polyamic acid.

[10] The liquid crystal aligning agent according to any one of [1] to [9], wherein the two or more kinds of tetracarboxylic acid derivatives further contain a tetracarboxylic acid dianhydride different from the compound represented by the above formula (1).

[11] The liquid crystal aligning agent according to

[10] , wherein the tetracarboxylic dianhydride different from the compound represented by the formula (1) has a cyclobutane ring structure.

[0011]

[12] A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of [1] to

[11] .

[13] A liquid crystal element comprising the liquid crystal alignment film according to

[12] .

[14] A method for producing a liquid crystal alignment film, comprising forming a coating film using the liquid crystal aligning agent according to any one of [1] to

[11] , and subjecting the coating film to an alignment treatment to impart liquid crystal alignment ability.

[15] A compound represented by the following formula (3): [ka] (In formula (3), Y 1 and Y 2 are each independently a tetravalent organic group. 2 is a divalent group containing a linear structure in the main chain in which two or more atoms are linearly linked, or -A 1 -N(R 3 )-A 2 -It is. A 1 and A 2 are each independently a substituted or unsubstituted phenylene group. 3 is a monovalent organic group. [Effects of the Invention]

[0012] According to the liquid crystal aligning agent of the present invention, a liquid crystal alignment film having excellent mechanical properties can be formed, and a liquid crystal device having excellent reliability while exhibiting good liquid crystal alignment properties and a high voltage holding ratio can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0013] Matters relating to aspects of the present disclosure will be described in detail below.

[0014] Here, in this specification, a numerical range indicated using "to" means that the numerical values ​​before and after "to" are included as the lower and upper limits. A "structural unit" refers to a unit that mainly constitutes the main chain structure, and at least two or more units are contained in the main chain structure. A structural unit is typically a repeating unit constituted based on one monomer. Note that a structural unit may be obtained by reacting a repeating unit having a reactive group with a compound having a functional group that can react with the reactive group.

[0015] As used herein, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The term "chain hydrocarbon group" refers to a linear hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure and is composed solely of a chain structure. However, the group may be saturated or unsaturated. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. However, the group does not necessarily have to be composed solely of an alicyclic hydrocarbon structure, and may also contain a chain structure as part of the ring structure. The term "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, the group does not necessarily have to be composed solely of an aromatic ring structure, and may contain a chain structure or an alicyclic hydrocarbon structure as part of the ring structure. The term "organic group" refers to an atomic group obtained by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound).

[0016] The "main chain" of a polymer refers to the "trunk" portion of the polymer, which is the longest chain of atoms. It is permissible for this "trunk" portion to contain a ring structure. For example, "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. A "side chain" refers to a portion branched from the "trunk" portion of the polymer.

[0017] <Liquid crystal alignment agent> The liquid crystal aligning agent of the present disclosure (hereinafter also simply referred to as "liquid crystal aligning agent") is a polymer composition in the form of a polymer blend containing multiple types of polymers. The liquid crystal aligning agent contains, as at least one polymer component, a polymer (A) which is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide and is obtained using two or more tetracarboxylic acid derivatives including a compound represented by the following formula (1). Specifically, the liquid crystal aligning agent satisfies at least one of the following requirements 1 and 2: Requirement 1: The composition further contains a polymer (B) different from the polymer (A). Requirement 2: The polymer (A) contains two or more types. [ka] (In formula (1), Y 1 and Y 2 are each independently a tetravalent organic group. 1 is a divalent organic group. Hereinafter, each component contained in the liquid crystal aligning agent and optional components will be described in detail. Hereinafter, the compound represented by the above formula (1) will also be referred to as "specific acid dianhydride".

[0018] <Polymer (A)> (Specified acid dianhydride) In the above formula (1), Y 1 or Y 2 The tetravalent organic group represented by the formula (I) is typically a group derived from a tetracarboxylic acid derivative. Examples of tetracarboxylic acid derivatives include tetracarboxylic acid dianhydrides, tetracarboxylic acid diesters, and tetracarboxylic acid diester dihalides. In this specification, "tetracarboxylic acid diester" refers to a compound in which two of the four carboxyl groups in a tetracarboxylic acid are esterified and the remaining two are carboxyl groups. "Tetracarboxylic acid diester dihalide" refers to a compound in which two of the four carboxyl groups in a tetracarboxylic acid are esterified and the remaining two are halogenated.

[0019] Examples of the tetracarboxylic acid dianhydride include aliphatic tetracarboxylic acid dianhydrides and aromatic tetracarboxylic acid dianhydrides. The aliphatic tetracarboxylic acid dianhydrides include chain tetracarboxylic acid dianhydrides and alicyclic tetracarboxylic acid dianhydrides.

[0020] Specific examples of the chain tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride, ethylenediaminetetraacetic dianhydride, etc. Specific examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 3-oxabicyclo[ 3.2.1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic acid 2:4,6:8-dianhydride, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic acid 2:3,5:6-dianhydride, 4,9-dioxatricyclo[5.3.1.0]octane-2,4,6,8-tetracarboxylic acid 2:3,5:6-dianhydride 2,6 ]undecane-3,5,8,10-tetraone, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, and the like.

[0021] Specific examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, p-phenylene bis(trimellitic acid monoester anhydride), ethylene glycol bis(anhydrotrimellitate), 1,3-propylene glycol bis(anhydrotrimellitate), 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-biphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, 4,4'-carbonyldiphthalic anhydride, etc. In addition to the above, examples of tetracarboxylic dianhydrides include the tetracarboxylic dianhydrides described in JP 2010-97188 A.

[0022] Examples of the tetracarboxylic acid diester and tetracarboxylic acid diester dihalide include compounds having a structure corresponding to the tetracarboxylic acid dianhydrides exemplified above.

[0023] Y 1 and Y 2 It is preferable that Y has an alicyclic structure or an aromatic ring structure, in that when a liquid crystal alignment film is formed using a liquid crystal aligning agent containing the polymer (A), a liquid crystal device exhibiting good liquid crystal alignment properties, voltage holding characteristics, and reliability can be obtained. Also, Y is preferable in that it can increase the solubility of the polymer (A) and can form a liquid crystal alignment film with better voltage holding characteristics and reliability. 1 and Y 2 More preferably, has an alicyclic structure.

[0024] Y 1 and Y 2 When Y has an alicyclic structure, 1 and Y 2 is preferably a group in which four hydrogen atoms have been removed from a substituted or unsubstituted aliphatic ring. The aliphatic ring may be saturated or unsaturated, but is preferably a saturated aliphatic ring. 1 and Y 2 When has an alicyclic structure, preferred specific examples include groups represented by the following formulas (A-1) to (A-9) and groups in which a substituent has been introduced into the ring in the following formulas (A-1) to (A-9). [ka] (In formulas (A-1) to (A-9), "*" represents a bond.)

[0025] When a coating film formed by a liquid crystal alignment agent is given liquid crystal alignment ability by a photoalignment method, a liquid crystal alignment film with excellent liquid crystal alignment properties can be obtained. 1 and Y 2 Preferably, Y has a cyclobutane ring structure. 1 , Y 2 When Y has a cyclobutane ring structure, 1 , Y 2 is preferably a tetravalent organic group represented by the following formula (4). [ka] (In formula (4), R 11 , R 12 , R 13 and R 14 are each independently a hydrogen atom, a halogen atom, or a monovalent organic group.

[0026] In the above formula (4), R 11 , R 12 , R 13 or R 14 Examples of the monovalent organic group represented by the formula include an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogenated alkoxy group having 1 to 6 carbon atoms. R 11 , R 12 , R 13 and R 14 Of the above, is preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, a halogenated alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a halogenated alkoxy group having 1 to 3 carbon atoms, and more preferably a hydrogen atom, a fluorine atom, an alkyl group having 1 to 3 carbon atoms, or a fluoroalkyl group having 1 to 3 carbon atoms.

[0027] When the liquid crystal alignment ability is imparted to the coating film by the photo-alignment method, a liquid crystal element exhibiting good liquid crystal alignment property can be obtained by the photo-reaction. 1 and Y 2 is R in the above formula (4). 11 ~R 14 is a tetravalent group which is a hydrogen atom, or R 11 and R 14 is a methyl group, and R 12 or R 13 Among these, R in the above formula (4) is particularly preferably a tetravalent group in which R is a hydrogen atom. 11 and R 14 is a methyl group, and R 12 or R 13 is preferably a tetravalent group in which R is a hydrogen atom.

[0028] Y in the above formula (1) 1 and Y 2 may be the same or different. In addition to the ease of synthesis of the specific acid dianhydride, Y is preferred in that it can form a liquid crystal alignment film with excellent liquid crystal alignment properties and voltage retention characteristics. 1 and Y 2 are preferably of the same structure.

[0029] X in the above formula (1) 1 The divalent organic group represented by the formula (I) is a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms, and any methylene group in the substituted or unsubstituted hydrocarbon group is -O-, -S-, -CO-, -NR 20 -, -COO-, -CONR 20 -,-OCONR 20 -, -NR 20 CONR 20 - or -SO2- substituted divalent group having 1 to 20 carbon atoms (provided that R 20 represents a hydrogen atom or a monovalent organic group (the same applies hereinafter), a divalent group having a heterocyclic structure, and the like.

[0030] Examples of divalent hydrocarbon groups having 1 to 20 carbon atoms include saturated or unsaturated divalent chain hydrocarbon groups having 1 to 20 carbon atoms, divalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, and divalent aromatic hydrocarbon groups having 6 to 20 carbon atoms. Examples of the substituent include halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.), hydroxyl groups, carboxy groups, nitro groups, and cyano groups.

[0031] R 20 Examples of the monovalent organic group represented by the formula (I) include monovalent hydrocarbon groups having 1 to 12 carbon atoms and groups that are eliminated by heat or light (hereinafter also referred to as "eliminating groups"). Examples of monovalent hydrocarbon groups having 1 to 12 carbon atoms include monovalent linear hydrocarbon groups, monovalent alicyclic hydrocarbon groups, and monovalent aromatic hydrocarbon groups. Of these, alkyl groups having 1 to 6 carbon atoms are preferred, and alkyl groups having 1 to 4 carbon atoms are more preferred.

[0032] Examples of leaving groups include carbamate-based leaving groups, amide-based leaving groups, imide-based leaving groups, and sulfonamide-based leaving groups. Of these, carbamate-based leaving groups are preferred because of their high thermal releasability. Specific examples of carbamate-based leaving groups include tert-butoxycarbonyl (Boc), benzyloxycarbonyl, 1,1-dimethyl-2-haloethyloxycarbonyl, allyloxycarbonyl, 2-(trimethylsilyl)ethoxycarbonyl, and 9-fluorenylmethyloxycarbonyl (F-moc) groups. Of these, alkyloxycarbonyl groups having a branched alkyl group having 3 to 6 carbon atoms are preferred, and tert-butoxycarbonyl (Boc) groups are particularly preferred, because they have excellent thermal releasability and can reduce the amount of deprotected moieties remaining in the film.

[0033] X is preferred in that it can provide liquid crystal devices with excellent liquid crystal alignment and reliability. 1 Preferably, X has an aromatic ring structure. In addition, X is a preferable compound in that it can achieve both good liquid crystal alignment properties in a liquid crystal device and good rubbing resistance of a coating film. 1 It is preferable that X contains a linear structure in the main chain. 1A preferred specific example of is a divalent group represented by the following formula (5): [ka] (In formula (5), Ar 1 and Ar 2 are each independently a divalent aromatic ring group. 1 represents a single bond or a divalent chain group. n is an integer of 0 to 3. "*" represents a bond.

[0034] In the above formula (5), Ar 1 or Ar 2 The divalent aromatic ring group represented by the formula (I) is a group in which two hydrogen atoms have been removed from the ring portion of a substituted or unsubstituted aromatic ring. Examples of aromatic rings include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, and a biphenyl ring; and aromatic heterocycles such as a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, a furan ring, and a thiophene ring. Among these, the aromatic ring constituting the divalent aromatic ring group is preferably a benzene ring, a naphthalene ring, a pyridine ring, or a pyrimidine ring, in view of their superior liquid crystal alignment properties and voltage retention characteristics. When the divalent aromatic ring group has a substituent on the ring portion, examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group, and a hydroxyl group.

[0035] L 1 The chain group represented by the formula (I) has a chain structure and does not have a ring structure. The chain group may be saturated or unsaturated as long as it does not have a ring structure. 1 Specific examples of the group include -O-, -S-, -CO-, and -NR 20 -, -COO-, -CONR 20 -,-OCONR 20 -, -NR 20 CONR 20 -, -SO2-, a divalent chain hydrocarbon group having 1 to 20 carbon atoms, any methylene group in the chain hydrocarbon group is -O-, -S-, -CO-, -NR 20 -, -COO-, -CONR 20 -,-OCONR 20 -, -NR 20 CONR 20Examples of such divalent groups include those having 1 to 20 carbon atoms, each of which is substituted with - or -SO2-.

[0036] L 1 is a single bond or A 1 and A 2 A divalent group having 1 to 12 atoms constituting a straight chain connecting L and L is preferred. 1 When L is a divalent chain group, 1 In A 1 and A 2 The number of atoms constituting the straight chain connecting A is more preferably 1 to 6, and even more preferably 1 to 4. 1 and A 2 The "straight chain connecting the specific acid dianhydride and the specific acid dianhydride" is a portion that constitutes a part of the main chain of the specific acid dianhydride and is introduced into the main chain of the polymer (A).

[0037] n is preferably 0 or 1. When n is 1, L 1 is a group of two or more atoms linked in a straight chain. 1 and A 2 or -NR 20 - is preferred.

[0038] Specific examples of the specific acid dianhydride include compounds represented by the following formulas (1-1) to (1-27). [ka] [ka] [ka]

[0039] The polymer (A) contains structural units derived from two or more tetracarboxylic acid derivatives. The tetracarboxylic acid derivative constituting the polymer (A) may be the specific acid dianhydride alone, or may be the specific acid dianhydride and a tetracarboxylic acid dianhydride other than the compound represented by the formula (1) (hereinafter also referred to as "other acid dianhydrides").

[0040] (Other acid dianhydrides) Other acid dianhydrides include those represented by the formula (1) above: 1 or Y 2 Examples of the other acid dianhydrides include the same compounds as those exemplified as the tetracarboxylic acid dianhydrides constituting the tetravalent organic group represented by the formula (1). The other acid dianhydrides are preferably alicyclic tetracarboxylic acid dianhydrides, since they can provide a liquid crystal device with excellent liquid crystal alignment properties and voltage retention characteristics. Specific examples of preferred other acid dianhydrides include compounds represented by the following formula (2): [ka] (In formula (2), Y 3 is a tetravalent group having an alicyclic structure and having 4 to 12 carbon atoms.

[0041] In the above formula (2), Y 3 Specific examples of the tetravalent group represented by the formula (A-1) to the formula (A-9) above include the tetravalent groups represented by the formula (A-1) to the formula (A-9) above, and the tetravalent groups in which a substituent has been introduced into the ring in the formula (A-1) to the formula (A-9) above. 3 is preferably a tetravalent group represented by the above formula (4).

[0042] As other acid dianhydrides, tetracarboxylic acid dianhydrides having a cyclobutane ring structure are preferred, and at least one of 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride and 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride is more preferred, with 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride being particularly preferred, in that when a coating film formed from a liquid crystal alignment agent is given liquid crystal alignment ability by a photoalignment method, a liquid crystal element that exhibits good liquid crystal alignment properties can be obtained by a photoreaction.

[0043] Among the tetracarboxylic acid derivatives constituting the polymer (A), the proportion of the specific acid dianhydride is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, based on the total amount of the tetracarboxylic acid derivatives constituting the polymer (A). A proportion of the specific acid dianhydride within the above range is advantageous in that it can further increase the voltage holding ratio of a liquid crystal element obtained using the liquid crystal aligning agent. Furthermore, from the viewpoint of ensuring the liquid crystal alignment properties of the liquid crystal element and the mechanical properties of the liquid crystal alignment film, the proportion of the specific acid dianhydride is preferably 98 mol% or less, more preferably 95 mol% or less, and even more preferably 90 mol% or less, based on the total amount of the tetracarboxylic acid derivatives constituting the polymer (A).

[0044] (Synthesis of Polymer (A)) The polymer (A) can be obtained by a method including a step of reacting two or more kinds of tetracarboxylic acid derivatives with a diamine compound.

[0045] Polyamic acid When the polymer (A) is a polyamic acid, the polyamic acid (hereinafter also referred to as "polyamic acid (A)") can be obtained by reacting (polycondensation reaction) two or more kinds of tetracarboxylic acid dianhydrides including a specific acid dianhydride with a diamine compound.

[0046] The diamine compound constituting the polyamic acid (A) is not particularly limited. Examples of the diamine compound include aliphatic diamines, aromatic diamines, and diaminoorganosiloxanes. Examples of the aliphatic diamine include linear diamines and alicyclic diamines.

[0047] Specific examples of diamine compounds include chain diamines such as metaxylylenediamine and hexamethylenediamine, and alicyclic diamines such as 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine).

[0048] Aromatic diamines include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl ether, 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, 2,2-bis(4-aminophenyl)hexaphenyl Fluoropropane, 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-bis(4-aminophenyl)-piperazine, bis[2- main-chain diamines such as N,N'-di(4-aminophenyl)ethyl]hexanedioic acid, 4,4'-diaminodiphenethyl urea, N,N'-di(4-amino-2-pyridyl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine, N,N'-bis[2-(4-aminophenyl)ethyl]hexanediamide, and N,N'-bis[2-(4-aminophenyl)ethyl]-N,N'-di(tert-butoxycarbonyl)hexanediamide; 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-di Cholestanyl aminobenzoate, cholestenyl 3,5-diaminobenzoate, lanostaniyl 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, 5ξ-cholestan-3-yl 3,5-diaminobenzoate, the following formula (E-1): [ka] (In formula (E-1), X I and X II are each independently a single bond, -O-, *-COO-, or *-OCO- (where * indicates the bond to the diaminophenyl group). I is an alkanediyl group having 1 to 3 carbon atoms. II R is a single bond or an alkanediyl group having 1 to 3 carbon atoms. III is an alkyl group, alkoxy group, fluoroalkyl group, or fluoroalkoxy group having 1 to 20 carbon atoms. a is 0 or 1. b is an integer of 0 to 3. c is an integer of 0 to 2. d is 0 or 1, provided that 1≦a+b+c≦3. and side chain diamines such as compounds represented by the following formula:

[0049] Examples of the compound represented by formula (E-1) include compounds represented by the following formulas (E-1-1) to (E-1-4). [ka]

[0050] Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane.

[0051] Further specific examples of the diamine compound include the diamines described in JP-A-2010-97188 and 1 -N(R 1 )-* 1 The partial structure represented by (where R 1 is a hydrogen atom or a monovalent organic group. 1 " represents a bond to an atom other than a hydrogen atom.) and a nitrogen-containing heterocycle (hereinafter also referred to as "nitrogen-containing diamine").

[0052] For nitrogen-containing diamines, R 1 The monovalent organic group represented by the formula (1) is X 1 In the explanation of R 20 The explanations of the specific and preferred examples given above as the monovalent organic group represented by the formula (I) can be cited. 1 -N(R 1 )-* 1 Atoms other than hydrogen atoms adjacent to the partial structure represented by the symbol "*" include carbon atoms and nitrogen atoms. 1 " are preferably bonds to atoms other than hydrogen atoms.

[0053] The nitrogen-containing heterocycle may be an aromatic heterocycle or an aliphatic heterocycle. Specific examples of these include aromatic heterocycles such as a pyrrole ring, a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, a carbazole ring, and a benzimidazole ring; and aliphatic heterocycles such as a piperidine ring, a piperazine ring, and a heptamethyleneimine ring.

[0054] Specific examples of the nitrogen-containing diamine include compounds represented by the following formula: [ka] [ka] [ka]

[0055] The polyamic acid (A) can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound, optionally together with a molecular weight modifier. The ratio of the tetracarboxylic dianhydride and the diamine compound used in the synthesis reaction of the polyamic acid (A) is preferably such that 0.2 to 1.5 equivalents, and more preferably 0.5 to 1.2 equivalents, of the acid anhydride groups of the tetracarboxylic dianhydride are used per equivalent of the amino groups of the diamine compound.

[0056] 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 proportion 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 used.

[0057] The synthesis reaction of the polyamic acid (A) is preferably carried out in an organic solvent, at a reaction temperature of preferably −20° C. to 80° C., more preferably 0 to 60° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 18 hours.

[0058] Examples of organic solvents used in the reaction include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Particularly preferred organic solvents include one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenols. Alternatively, it is preferred to use a mixture of one or more of these solvents with other organic solvents (e.g., butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount of organic solvent (a) 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.

[0059] In this manner, a reaction solution containing the polyamic acid (A) dissolved therein is obtained. This reaction solution may be used directly for preparing a liquid crystal aligning agent, or the polyamic acid (A) contained in the reaction solution may be isolated and then used for preparing a liquid crystal aligning agent, or the isolated polyamic acid (A) may be purified and then used for preparing a liquid crystal aligning agent. When polyamic acid (A) is subjected to dehydration ring-closure to form a polyimide, the reaction solution may be used directly for the dehydration ring-closure reaction, or the polyamic acid (A) contained in the reaction solution may be isolated and then used for the dehydration ring-closure reaction, or the isolated polyamic acid (A) may be purified and then used for the dehydration ring-closure reaction. The isolation and purification of the polyamic acid (A) can be carried out according to known methods.

[0060] Polyamic acid ester The polyamic acid ester as the polymer (A) (hereinafter also referred to as "polyamic acid ester (A)") can be obtained, for example, by [I] a method of reacting the polyamic acid (A) obtained by the above synthesis reaction with an esterifying agent; [II] a method of reacting a tetracarboxylic acid derivative containing a specific acid dianhydride and a tetracarboxylic acid diester with a diamine compound; or [III] a method of reacting a tetracarboxylic acid derivative containing a specific acid dianhydride and a tetracarboxylic acid diester dihalide with a diamine compound.

[0061] Examples of the esterifying agent used in the method [I] include hydroxyl group-containing compounds, acetal compounds, halides, epoxy group-containing compounds, etc. Specific examples of these include: hydroxyl group-containing compounds such as alcohols (e.g., methanol, ethanol, and propanol), and phenols (e.g., phenol and cresol); acetal compounds such as N,N-dimethylformamide diethyl acetal and N,N-diethylformamide diethyl acetal; halides such as methyl bromide, ethyl bromide, stearyl bromide, methyl chloride, stearyl chloride, and 1,1,1-trifluoro-2-iodoethane; and epoxy group-containing compounds such as propylene oxide.

[0062] The tetracarboxylic acid diester used in the method [II] can be obtained, for example, by ring-opening the tetracarboxylic acid dianhydride exemplified in the explanation of the synthesis of the polyamic acid (A) with an alcohol such as methanol or ethanol.

[0063] The tetracarboxylic acid diester dihalide used in the method [III] can be obtained, for example, by reacting the tetracarboxylic acid diester obtained as described above with a suitable chlorinating agent such as thionyl chloride.

[0064] The polyamic acid ester (A) contained in the liquid crystal aligning agent 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 (A) is dissolved may be used directly for preparing the liquid crystal aligning agent, or the polyamic acid ester (A) contained in the reaction solution may be isolated and then used for preparing the liquid crystal aligning agent, or the isolated polyamic acid ester (A) may be purified and then used for preparing the liquid crystal aligning agent. The polyamic acid ester (A) can be isolated and purified according to known methods.

[0065] Polyimide The polyimide as the polymer (A) (hereinafter also referred to as "polyimide (A)") can be obtained, for example, by dehydrating and ring-closing the polyamic acid (A) synthesized as described above to thereby form an imidized product.

[0066] The polyimide (A) may be a fully imidized product in which all amic acid structures contained in its precursor polyamic acid (A) have been dehydrated and cyclized, or a partially imidized product in which only a portion of the amic acid structures have been dehydrated and cyclized, resulting in both amic acid structures and imide ring structures. The polyimide (A) preferably has an imidization rate of 20% or more, more preferably 30 to 99%. The imidization rate is the ratio, expressed as a percentage, of the number of imide ring structures to the total number of amic acid structures and imide ring structures in the polyimide (A). Some of the imide rings may be isoimide rings.

[0067] The dehydration ring-closure of the polyamic acid (A) is preferably carried out by heating the polyamic acid (A), or by dissolving the polyamic acid (A) in an organic solvent, adding a dehydrating agent and a dehydration ring-closure catalyst to the solution, and heating as necessary.

[0068] In the method of adding a dehydrating agent and a dehydration ring-closing catalyst to a solution of polyamic acid (A), for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride can be used as the dehydrating agent. The amount of the dehydrating agent used is preferably 0.01 to 20 mol per mol of the amic acid structure of the polyamic acid (A). The amount of the dehydration ring-closing catalyst used is preferably 0.01 to 10 mol per mol of the dehydrating agent used. Examples of organic solvents used in the dehydration ring-closing reaction include the organic solvents exemplified for use in the synthesis of polyamic acid (A). The reaction temperature for the dehydration ring-closing reaction is preferably 0 to 180°C, more preferably 10 to 150°C. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

[0069] In this way, a reaction solution containing polyimide (A) is obtained. This reaction solution may be used for preparing a liquid crystal aligning agent as it is, or may be used for preparing a liquid crystal aligning agent after removing the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution, or may be used for preparing a liquid crystal aligning agent after isolating polyimide (A), or may be used for preparing a liquid crystal aligning agent after purifying the isolated polyimide (A). These purification operations can be performed according to known methods.

[0070] The solution viscosity of the polymer (A) contained in the liquid crystal aligning agent is preferably 10 to 800 mPa·s when the solution has a concentration of 10% by mass, and more preferably 15 to 500 mPa·s. The solution viscosity (mPa·s) is a value measured at 25°C using an E-type rotational viscometer for a 10% by mass polymer solution prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0071] The weight average molecular weight (Mw) of the polymer (A) measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1,000 to 500,000, and more preferably 5,000 to 100,000. The molecular weight distribution (Mw / Mn), which is expressed as the ratio of Mw to the number average molecular weight (Mn) measured by GPC in terms of polystyrene, is preferably 15 or less, and more preferably 10 or less.

[0072] When the liquid crystal aligning agent satisfies requirement 1, the content of polymer (A) in the liquid crystal aligning agent is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total mass of the solid content contained in the liquid crystal aligning agent (total mass of components other than the solvent of the liquid crystal aligning agent), from the viewpoint of obtaining a liquid crystal device having excellent liquid crystal alignment properties and voltage retention characteristics, high film strength, and excellent reliability. Also, the content of polymer (A) is preferably 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less, based on the total mass of the solid content contained in the liquid crystal aligning agent.

[0073] When the liquid crystal aligning agent satisfies requirement 2, the liquid crystal aligning agent contains two or more polymers (A) as polymer components. The content of each polymer (A) is preferably 5% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, based on the total mass of the polymers (A) contained in the liquid crystal aligning agent, from the viewpoint of fully obtaining the effects of improving the liquid crystal alignment property, voltage holding ratio, and reliability due to the polymer blend.

[0074] As the polymer (A), at least one selected from the group consisting of polyamic acid and polyimide is preferred, and polyamic acid is particularly preferred, in that a liquid crystal alignment film having excellent mechanical properties can be formed.

[0075] <Polymer (B)> The polymer (B) is not particularly limited as long as it is obtained from a monomer that does not contain the compound represented by formula (1). Examples of the main skeleton of the polymer (B) include polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamideimide, polyimine, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, and addition polymer. Examples of the addition polymer include (meth)acrylic polymer, styrene polymer, maleimide polymer, (meth)acrylic-styrene copolymer, (meth)acrylic-maleimide copolymer, (meth)acrylic-styrene-maleimide copolymer, and styrene-maleimide copolymer.

[0076] Among these, polymer (B) is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer, and more preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, in that it exhibits good liquid crystal alignment properties and voltage retention characteristics when used in combination with polymer (A).

[0077] When polymer (B) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, polymer (B) can be obtained by a method including a step of reacting a tetracarboxylic acid derivative with a diamine compound, similar to polymer (A). Examples of the tetracarboxylic acid derivative used in the synthesis of polymer (B) include the same acid dianhydrides as those exemplified in the description of polymer (A). Examples of the diamine compound used in the synthesis of polymer (B) include the same compounds as those exemplified in the description of polymer (A).

[0078] When the liquid crystal aligning agent satisfies requirement 1, the content of polymer (B) in the liquid crystal aligning agent is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, based on the total mass of the solid contents contained in the liquid crystal aligning agent. Furthermore, the content of polymer (B) is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, based on the total mass of the solid contents contained in the liquid crystal aligning agent. By setting the content of polymer (B) within the above range, a liquid crystal alignment film exhibiting good mechanical properties can be obtained, and a liquid crystal device excellent in liquid crystal alignment properties and voltage retention characteristics can be obtained.

[0079] The liquid crystal aligning agent of the present disclosure contains, as at least one of the polymer (A) and the polymer (B), 1 -N(R 1 )-* 1 and at least one selected from the group consisting of nitrogen-containing heterocycles. By including a structural unit derived from a nitrogen-containing diamine in the polymer component, a liquid crystal device with improved liquid crystal alignment properties can be obtained. 1 is a hydrogen atom or a monovalent organic group. 1 " represents a bond to an atom other than a hydrogen atom. For details and specific examples of the nitrogen-containing diamine, the explanation of the polymer (A) is cited.

[0080] As a nitrogen-containing diamine, it is highly effective in improving liquid crystal alignment. 1 -N(R 1 )-* 1 Alternatively, a compound having a structure that allows a nitrogen-containing heterocycle to be introduced into the main chain of the polymer can be preferably used.

[0081] In terms of being highly effective in improving the liquid crystal alignment of a liquid crystal element, a liquid crystal aligning agent that satisfies requirement 1 preferably has at least the polymer (B) of the polymers (A) and (B) containing a structural unit derived from a nitrogen-containing diamine, and more preferably has both the polymer (A) and the polymer (B) containing a structural unit derived from a nitrogen-containing diamine. Also, a liquid crystal aligning agent that satisfies requirement 2 preferably has all of the two or more polymers (A) containing a structural unit derived from a nitrogen-containing diamine.

[0082] For a polymer containing structural units derived from a nitrogen-containing diamine, the content of the structural units derived from a nitrogen-containing diamine 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 structural units derived from diamines constituting the polymer.

[0083] From the viewpoint of further improving the liquid crystal alignment property, the liquid crystal aligning agent of the present disclosure contains at least one of the polymer (A) and the polymer (B) having a -N(R 2 )- (wherein R 2 is a monovalent group which is eliminated by heat or light. 2 The leaving group represented by the formula (1) is X 1 In the explanation of R 20 The explanations of specific examples and preferred examples of the monovalent leaving group represented by the formula (I) can be applied to the polymer (A) and the polymer (B). 2 The method for introducing the partial structure represented by -N(R)- is not particularly limited. 2 )- can be easily introduced into the compound. 2 It is preferable to carry out the polymerization using a diamine having a partial structure represented by —N(R )-. Such a diamine is preferably a diamine having a partial structure represented by —N(R 2 )-.

[0084] The liquid crystal aligning agent of the present disclosure has a high effect of improving the liquid crystal alignment property of a liquid crystal element, and is preferably a polymer (A) containing -N(R 2It is preferable that the polymer contains a polymer having a partial structure represented by —N(R 2 It is more preferable that the polymer contains a structural unit derived from a diamine having a partial structure represented by —N(R 2 With respect to a polymer containing a structural unit derived from a diamine having a partial structure represented by the formula: (III)-, the content of the structural unit 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 structural units derived from diamine constituting the polymer.

[0085] [Other ingredients] The liquid crystal aligning agent may further contain components (hereinafter also referred to as "other components") other than the polymer (A) and the polymer (B). Examples of the other components include a crosslinking agent, an adhesion aid, and a solvent.

[0086] Crosslinking agent By further incorporating a crosslinking agent into the liquid crystal aligning agent of the present disclosure, it is possible to further improve the film strength and the reliability of the liquid crystal element. Examples of the crosslinking agent include compounds having two or more groups in the molecule, each of which is at least one type of group selected from the group consisting of 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, a polymerizable carbon-carbon bond-containing group, an amino group, and a protected amino group.

[0087] From the viewpoint of sufficiently improving the reliability of liquid crystal devices, the number of crosslinkable groups contained in one molecule of the crosslinking agent is preferably 2 to 10, more preferably 2 to 6. The molecular weight of the crosslinking agent is preferably 100 to 1,000, more preferably 100 to 800, and even more preferably 100 to 700.

[0088] Specific examples of the crosslinking agent include compounds having a cyclic ether group or a cyclic thioether group, such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, triglycidyl isocyanurate, glycerol polyglycidyl ether, pentaerythritol tetraglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, N,N',N',N'-tetraglycidyl glycoluril, 1,6-hexanediol diglycidyl ether, trimethyl Examples of such glycerols include methyl glycerol propane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N-diglycidyl-benzylamine, N,N-diglycidyl-aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine, and epoxidation reaction products of 2,2'-diallylbisphenol A diallyl ether with hydrogen peroxide.

[0089] Examples of compounds having an isocyanate group or a protected isocyanate group include tolylene diisocyanate, xylylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, compounds in which the isocyanate group of these compounds is protected with 3,6-dimethylpyrazole, methyl ethyl ketoxime, diethyl malonate, or ε-caprolactam, and compounds represented by the following formula (d1-1).

[0090] Examples of compounds having a methylol group or a protected methylol group include compounds represented by the following formulas (d2-1) to (d2-5). Examples of compounds having a hydroxyalkylamide group or a protected hydroxyalkylamide group include compounds represented by the following formulas (d3-1) to (d3-8). Examples of the compound having a cyclic carbonate group include compounds represented by the following formulas (d4-1) and (d4-2).

[0091] Examples of compounds having a polymerizable carbon-carbon bond-containing group include compounds having a (meth)acryloyl group, a maleimide group, an alkenyl group, a vinylphenyl group, a vinyl ether group, or a 3-methylenetetrahydrofuran-2(3H)-one-5-yl group. Specific examples of these include ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and compounds represented by the following formulas (d5-1) to (d5-7). Examples of compounds having an amino group or a protected amino group include compounds represented by the following formulae (d6-1) to (d6-5).

[0092] [ka] [ka] (In formula (d2-4), Ac is an acetyl group.) [ka] [ka] [ka] [ka]

[0093] When a crosslinking agent is contained in the liquid crystal aligning agent of the present disclosure, the content of the crosslinking agent is preferably 0.5 parts by mass or more relative to 100 parts by mass of the total amount of polymer components contained in the liquid crystal aligning agent, from the viewpoint of improving the mechanical properties of the liquid crystal alignment film and further improving the reliability of the liquid crystal element. From the above viewpoints, the content 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 polymer components. Furthermore, from the viewpoint of obtaining a liquid crystal element having good liquid crystal alignment properties and voltage retention characteristics, and from the viewpoint of improving the storage stability of the liquid crystal aligning agent, the content of the crosslinking agent is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the total amount of polymer components.

[0094] Adhesion aid The adhesion aid is a component that improves the adhesion between a liquid crystal alignment film formed using a liquid crystal aligning agent and a substrate or a sealing material. A functional silane coupling agent having a reactive functional group can be preferably used as the adhesion aid. Examples of the reactive functional group possessed by the functional silane coupling agent include a carboxy group, a (meth)acryloyl group, an oxiranyl group, an oxetanyl group, a vinyl group, and an isocyanate group.

[0095] Specific examples of functional coupling agents include trimethoxysilylbenzoic acid, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane.

[0096] When the liquid crystal aligning agent of the present disclosure contains an adhesion aid, the content of the adhesion aid is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass, relative to 100 parts by mass of the total amount of polymer components contained in the liquid crystal aligning agent.

[0097] ·solvent The liquid crystal aligning agent of the present disclosure is prepared as a liquid composition in which the polymer component and other components used as needed are dispersed or dissolved preferably in a suitable solvent.

[0098] Examples of the organic solvent to be used include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, and ethylene glycol-n-butyl ether ( butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate, and the like.

[0099] In addition to the above, other components include, for example, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, acid generators, base generators, radical generators, etc. The blending ratio of each of these components can be appropriately selected depending on each compound within a range that does not impair the effects of the present disclosure.

[0100] The solid content concentration in the liquid crystal aligning agent (the proportion of the total mass of the components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected taking into consideration viscosity, volatility, etc., but is preferably in the range of 1 to 10 mass %. That is, the liquid crystal aligning agent is applied to the surface of a substrate as described below, and preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that will become a liquid crystal alignment film. In this case, if the solid content concentration is 1 mass % or more, the coating film can have a sufficient thickness, and a good liquid crystal alignment film tends to be easily obtained. If the solid content concentration is 10 mass % or less, the coating film thickness does not become too large, and an increase in the viscosity of the liquid crystal aligning agent can be suppressed, tending to improve the coatability.

[0101] The particularly preferred range of solid content varies depending on the application of the liquid crystal aligning agent and the method used to apply the liquid crystal aligning agent to a substrate. For example, when applying a liquid crystal aligning agent for a liquid crystal display device to a substrate by a spinner method, the solid content (the ratio of the total mass of all components in the liquid crystal aligning agent other than the solvent to the total mass of the liquid crystal aligning agent) is particularly preferably in the range of 1.5 to 4.5 mass%. When using a printing method, the solid content is particularly preferably in the range of 3 to 9 mass%, thereby adjusting the solution viscosity to a range of 12 to 50 mPa·s. When using an inkjet method, the solid content is particularly preferably in the range of 1 to 5 mass%, thereby adjusting the solution viscosity to a range of 3 to 15 mPa·s. The temperature when preparing the liquid crystal aligning agent is preferably 10 to 50°C, more preferably 20 to 30°C. Furthermore, with regard to the liquid crystal aligning agent for the retardation film, from the viewpoint of the applicability of the liquid crystal aligning agent and the thickness of the coating film to be formed being appropriate, the solid content concentration of the liquid crystal aligning agent is preferably in the range of 0.2 to 10 mass %, more preferably in the range of 3 to 10 mass %.

[0102] <Tetracarboxylic acid dianhydride> According to the present disclosure, there is provided a compound represented by the following formula (3): The compound represented by the following formula (3) is useful as a material for forming a liquid crystal alignment film having excellent mechanical properties, and for obtaining a liquid crystal device having excellent liquid crystal alignment properties, voltage retention properties, and high reliability. [ka] (In formula (3), Y 1 and Y 2 are each independently a tetravalent organic group. 2 is a divalent group containing a linear structure in the main chain in which two or more atoms are linearly linked, or -A 1 -N(R 3 )-A 2 -It is. A 1 and A 2 are each independently a substituted or unsubstituted phenylene group. 3 is a monovalent organic group.

[0103] In the above formula (3), Y 1 and Y 2 Specific and preferred examples are the same as those given in the explanation of formula (1) above.

[0104] X 2 is a divalent group containing a linear structure in the main chain in which two or more atoms are linearly linked, the linear structure includes a divalent linear hydrocarbon group having 1 to 20 carbon atoms, and any methylene group in the linear hydrocarbon group is -O-, -S-, -CO-, -NR 20 -, -COO-, -CONR 20 -,-OCONR 20 -, -NR 20 CONR 20 Examples of such divalent groups include those having 1 to 20 carbon atoms, each of which is substituted with - or -SO2-. 2 A preferred example of the formula (5) is 1 a divalent linear hydrocarbon group having 1 to 20 carbon atoms, any methylene group in the linear hydrocarbon group being -O-, -S-, -CO-, -NR 20 -, -COO-, -CONR 20 -,-OCONR 20 -, -NR 20 CONR 20 and a divalent group having 1 to 20 carbon atoms substituted with - or -SO2-, wherein n is 1 to 3.

[0105] X 2 Ga-A 1 -N(R 3 )-A 2 -If A 1 , A 2 Examples of the substituent that R may have include an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group, and a hydroxyl group. 3 The monovalent organic group represented by the formula (1) is X 1 In the explanation of R 20 The explanations of the specific and preferred examples given as examples of the monovalent organic group represented by the following formula can be cited.

[0106] Specific examples of the compound represented by the above formula (3) include compounds represented by the above formulas (1-7) and (1-14) to (1-27).

[0107] The compound represented by the formula (3) can be synthesized by appropriately combining conventional methods of organic chemistry. 1 and a tetracarboxylic dianhydride having X 2 and a diamine having the formula (I) preferably in the presence of an organic solvent, followed by a dehydration ring-closure reaction.

[0108] In the reaction for obtaining the compound represented by the above formula (3), Y 1 and a tetracarboxylic dianhydride having X 2 The ratio of the tetracarboxylic acid dianhydride to the diamine having the formula (3) is preferably 1.6 to 3.0 equivalents, more preferably 1.7 to 2.5 equivalents, of the acid anhydride group of the tetracarboxylic acid dianhydride per equivalent of the amino group of the diamine. The reaction temperature is preferably 20 to 180°C, more preferably 20 to 120°C. The reaction time is preferably 0.2 to 24 hours, more preferably 0.5 to 18 hours. The dehydration ring-closing reaction can be carried out, for example, using a dehydrating agent (such as acetic anhydride) and heating as necessary. However, the synthesis method of the compound represented by formula (3) is not limited to the above.

[0109] <Liquid crystal alignment film and liquid crystal element> The liquid crystal alignment film of the present disclosure is formed using the liquid crystal aligning agent prepared as described above. One embodiment of a method for forming a liquid crystal alignment film includes the steps of forming a coating film using the liquid crystal aligning agent and then performing an alignment treatment on the coating film to impart liquid crystal alignment ability. The liquid crystal element of the present disclosure has a liquid crystal alignment film formed using the liquid crystal aligning agent described above. The operation mode of the liquid crystal in the liquid crystal element is not particularly limited, and various modes can be applied, for example, 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 following steps 1 to 3. In step 1, different substrates are used depending on the desired operation mode. Steps 2 and 3 are common to all operation modes.

[0110] <Step 1: Formation of coating film> First, a liquid crystal alignment agent is applied to a substrate, and the coated surface is preferably heated to form a coating film on the substrate. Examples of substrates that can be used include glass, such as float glass or soda glass; and transparent substrates made of resins, such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefin). When manufacturing TN, STN, or VA liquid crystal devices, two substrates with patterned transparent conductive films are used. On the other hand, when manufacturing IPS or FFS liquid crystal devices, one substrate with comb-shaped patterned electrodes and a counter substrate without electrodes are used. Examples of transparent conductive films that can be used include NESA films (registered trademark of PPG, USA) made of tin oxide (SnO), and ITO films made of indium oxide-tin oxide (InO-SnO). The liquid crystal alignment agent is applied to the substrate surface, preferably by offset printing, flexographic printing, spin coating, roll coating, or inkjet printing.

[0111] After the liquid crystal aligning agent is applied, preheating (pre-baking) is preferably carried out for the purpose of preventing dripping of the applied liquid crystal aligning agent. The pre-baking temperature is preferably 30 to 200°C, and the pre-baking time is preferably 0.25 to 10 minutes. Thereafter, a baking (post-baking) step is carried out for the purpose of removing the solvent in the applied liquid crystal aligning agent. The baking temperature (post-baking temperature) at this time is preferably 80 to 250°C, more preferably 80 to 200°C. The post-baking time is preferably 5 to 200 minutes. The thickness of the film thus formed is preferably 0.001 to 1 μm.

[0112] <Step 2: Alignment Treatment> When manufacturing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal device, the coating film formed in step 1 is subjected to a treatment (alignment treatment) to impart liquid crystal alignment ability. This imparts the ability to align liquid crystal molecules to the coating film, resulting in a liquid crystal alignment film. Examples of alignment treatments that can be used include rubbing, in which the coating film formed on the substrate is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton; and photoalignment, in which the coating film formed on the substrate is irradiated with light to impart liquid crystal alignment ability to the coating film. On the other hand, when manufacturing a vertical alignment (VA)-type liquid crystal device, the coating film formed in step 1 can be used as is as a liquid crystal alignment film. Furthermore, the coating film may be subjected to an alignment treatment to further enhance the liquid crystal alignment ability. Liquid crystal alignment films suitable for vertical alignment-type liquid crystal devices are also suitable for PSA-type liquid crystal devices.

[0113] In the photo-alignment treatment, light irradiation can be performed by irradiating the coating film after the post-bake step; irradiating the coating film after the pre-bake step but before the post-bake step; or irradiating the coating film while it is being heated in at least one of the pre-bake step and the post-bake step. The radiation to be irradiated to the coating film can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm. Preferably, ultraviolet light containing light with a wavelength of 200 to 400 nm is used. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When non-polarized radiation is used, the irradiation direction is an oblique direction.

[0114] Examples of light sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, excimer lasers, etc. The radiation dose on the substrate surface is preferably 400 to 50,000 J / m 2 and more preferably 1,000 to 20,000 J / m 2After the light irradiation for imparting alignment ability, the substrate surface may be washed with, for example, water, an organic solvent (e.g., methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.) or a mixture thereof, or the substrate may be heated.

[0115] <Step 3: Construction of liquid crystal cell> Two substrates with liquid crystal alignment films formed thereon are prepared as described above, and a liquid crystal cell is fabricated between the two substrates, with liquid crystal disposed adjacent to the liquid crystal alignment films. Examples of methods for fabricating a liquid crystal cell include placing two substrates facing each other with a gap between them so that the liquid crystal alignment films face each other, bonding the peripheries of the two substrates together with a sealant, injecting liquid crystal into the cell gap surrounded by the substrate surfaces and the sealant, and sealing the injection hole; an ODF method; and other methods. Examples of sealants that can be used include epoxy resins containing a curing agent and aluminum oxide spheres as spacers. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred. In the PSA mode, a liquid crystal cell is constructed by disposing a photopolymerizable compound together with liquid crystal between two substrates. After the liquid crystal cell is constructed, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates.

[0116] For each mode of liquid crystal cell, a polarizing plate is then attached to the outer surface of the liquid crystal cell as needed to form a liquid crystal element. Examples of polarizing plates include a polarizing film called an "H film" made by stretching and aligning polyvinyl alcohol and absorbing iodine, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

[0117] The liquid crystal element of the present disclosure can be effectively applied to various applications, specifically, for example, various display devices such as watches, 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 films, retardation films, and the like. [Example]

[0118] Hereinafter, the present invention will be described in more detail based on examples, but the present invention should not be construed as being limited by the following examples.

[0119] <Monomer synthesis> [Synthesis Example 1A] Compound (TA-1) was synthesized according to the following scheme. [ka]

[0120] 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (40 mmol) and N-methyl-2-pyrrolidone (NMP) (40 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred at 100°C for 30 minutes. An NMP solution of 2,2'-dimethyl-4,4'-diaminobiphenyl (20 mmol) was then added dropwise, followed by stirring at 100°C for 1 hour. Acetic anhydride (60 mmol) and N-methylpiperidine (10 mmol) were then added, followed by stirring at 100°C for 1 hour. After the reaction was complete, the reaction solution was filtered and poured into water to precipitate the product. The precipitate was filtered, washed with stirring in boiling water, and dried under vacuum at 60°C. The resulting solid was anhydrous in excess acetic anhydride / acetic acid to obtain 18.2 mmol of compound (TA-1). The structure of compound (TA-1) was confirmed by the nuclear magnetic resonance spectrum of the intramolecular hydrogen atoms. 1 The measurement data was shown below. 1 H-NMR (400MHz, [D6]-DMSO) δ: 7.91 (s, 2H), 7.82 (d, 2H), 7.22 (d, 2H), 4.05 (s, 2H), 3.78 (s, 2H), 2.57 (s, 6H), 1.27 (s, 12H).

[0121] [Synthesis example 2A] Compound (TA-3) was synthesized according to the following scheme. [ka]

[0122] 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (30 mmol) and NMP (40 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred at 100°C for 30 minutes. An NMP solution of 1,2-bis(4-aminophenoxy)ethane (15 mmol) was then added dropwise, followed by stirring at 100°C for 1 hour. Acetic anhydride (45 mmol) and N-methylpiperidine (7.5 mmol) were then added and stirred at 100°C for 1 hour. After the reaction was complete, the reaction solution was filtered and poured into water to precipitate the product. The precipitate was filtered, washed with stirring in boiling water, and dried in vacuum at 60°C. The resulting solid was anhydrified in excess acetic anhydride / acetic acid to obtain 17.3 mmol of compound (TA-3). The structure of compound (TA-3) was as follows: 1 The measurement data was shown below. 1 H-NMR (400MHz, [D6]-DMSO) δ: 7.08 (d, 4H), 6.97 (d, 4H), 4.50 (s, 4H), 4.04 (s, 2H), 3.79 (s, 2H), 1.28 (s, 12H).

[0123] [Synthesis example 3A] Compound (TA-6) was synthesized according to the following scheme. [ka]

[0124] 1,2,3,4-Cyclobutanetetracarboxylic dianhydride (40 mmol) and NMP (60 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred at 100°C for 30 minutes. An NMP solution of 1,5-bis(4-aminophenoxy)pentane (20 mmol) was then added dropwise, followed by stirring at 100°C for 1 hour. Acetic anhydride (60 mmol) and N-methylpiperidine (10 mmol) were then added, followed by stirring at 100°C for 1 hour. After the reaction was complete, the reaction solution was filtered and poured into water to precipitate the product. The precipitate was filtered, washed with stirring in boiling water, and dried in vacuum at 60°C. The resulting solid was anhydrified in excess acetic anhydride / acetic acid to obtain 18.5 mmol of compound (TA-6). The structure of compound (TA-6) was as follows: 1 The measurement data was shown below. 1 H-NMR (400MHz, [D6]-DMSO) δ: 8.54 (s, 4H), 7.19 (3, 4H), 6.97 (d, 4H), 4.10 (t, 4H), 1.82 (tt, 4H), 1.60 (tt, 2H).

[0125] <Polymer synthesis> Polymers were synthesized using the following monomers: In the following examples, the imidization rate of polyimide in the 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. After that, it was dissolved in deuterated dimethyl sulfoxide and measured at room temperature using tetramethylsilane as a standard substance. 1 H-NMR measurement was carried out. 1 The imidization rate [%] was calculated from the H-NMR spectrum using the following formula (F-1). Imidization rate [%] = (1 - (A 1 / (A 2 ×α)))×100 …(F-1) (In formula (F-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, and A 2is the peak area due to other protons, and α is the ratio of the number of other protons to one proton of the NH group in the polymer precursor (polyamic acid).

[0126] [Monomer] (Specified acid dianhydride) [ka]

[0127] (Other acid dianhydrides) [ka]

[0128] (Diamine compounds) [ka] [ka]

[0129] 1. Synthesis of polyamic acid [Synthesis Example 1] 40 parts by mole of compound (TA-1) and 60 parts by mole of compound (TB-1) as tetracarboxylic dianhydrides, and 50 parts by mole of compound (DA-4) and 50 parts by mole of compound (DA-11) as diamine compounds were dissolved in NMP, and the mixture was allowed to react at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamic acid (referred to as polymer (PA-1)).

[0130] [Synthesis Examples 2-17, 23-31] Polyamic acids (polymers (PA-2) to (PA-26)) were obtained by the same procedure as in Synthesis Example 1, except that the types and amounts of the tetracarboxylic dianhydrides and diamine compounds used were changed as shown in Tables 1 and 2. In Tables 1 and 2, the numerical values ​​for the tetracarboxylic dianhydrides (acid dianhydride 1, acid dianhydride 2, and acid dianhydride 3) represent the proportion (in parts by mole) of each compound used relative to 100 parts by mole of the total amount of the tetracarboxylic dianhydrides used in the synthesis of each polymer. The numerical values ​​for the diamine compounds (diamine 1, diamine 2, and diamine 3) represent the proportion (in parts by mole) of each compound used relative to 100 parts by mole of the total amount of the diamine compounds used in the synthesis of each polymer.

[0131] 2. Polyimide Synthesis [Synthesis Example 18] 30 moles of compound (TA-1) and 70 moles of compound (TB-1) as tetracarboxylic dianhydrides, and 50 moles of compound (DA-9) and 50 moles of compound (DA-11) as diamine compounds were dissolved in NMP and reacted at room temperature for 6 hours to obtain a solution containing 15% by weight of polyamic acid. Next, NMP was added to the resulting polyamic acid solution to obtain a solution with a polyamic acid concentration of 10% by weight, and pyridine and acetic anhydride were added, followed by 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 weight of polyimide with an imidization rate of 45% (referred to as polymer (PI-1)).

[0132] [Synthesis Examples 19-22, 32] Polyimides (polymers (PI-2) to (PI-6)) were obtained in the same manner as in Synthesis Example 18, except that the types and amounts of the tetracarboxylic dianhydrides and diamine compounds used were changed as shown in Tables 1 and 2, and the amounts of pyridine and acetic anhydride were adjusted to make the imidization ratios as shown in Tables 1 and 2.

[0133] [Table 1]

[0134] [Table 2]

[0135] <Preparation and Evaluation of Liquid Crystal Alignment Agent> Liquid crystal aligning agents were prepared using the polymers (PA-1 to PA-26, PI-1 to PI-6) obtained in Synthesis Examples 1 to 32 and the additives shown below, and were evaluated.

[0136] (additives) [ka]

[0137] [Example 1: Optical FFS type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent Polymer components (solid content: 50 parts by mass of polymer (PA-1), 50 parts by mass of polymer (PA-21)) and 5 parts by mass of compound (Ad-1) were diluted with NMP and butyl cellosolve (BC) to obtain a solution with a solvent composition of NMP / BC = 80 / 20 (mass ratio) and a solid content concentration of 3.5 mass%. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-1).

[0138] 2. Fabrication of FFS-type LCD elements using the photoalignment method A glass substrate (referred to as the first substrate) with a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) laminated in this order on one side, and a glass substrate (referred to as the second substrate) without an electrode were prepared. Next, a liquid crystal alignment agent (AL-1) was applied to the electrode-forming surface of the first substrate and one substrate surface of the second substrate using a spinner, and heated (pre-baked) on a hot plate at 80°C for 1 minute. This was followed by drying (post-baking) for 30 minutes in an oven at 230°C with the interior substituted with nitrogen, forming a coating film with an average thickness of 0.1 μm. The resulting coating film was irradiated with 1,000 J / m of linearly polarized ultraviolet light containing a 254 nm emission line using an Hg-Xe lamp. 2The coating film was then irradiated with light from the normal direction of the substrate to perform a photo-alignment treatment. The irradiation dose was measured using an actinometer measuring at a wavelength of 254 nm. The photo-aligned coating film was then heat-treated in a clean oven at 230°C for 30 minutes to form a liquid crystal alignment film. Next, for one of the pair of substrates on which the liquid crystal alignment film was formed, an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was applied by screen printing to the outer edge of the surface bearing the liquid crystal alignment film. The substrates were then stacked and pressed together so that the projection directions of the polarization axes on the substrate surfaces during light irradiation were antiparallel, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was injected between the pair of substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive to obtain a liquid crystal cell. Furthermore, to remove flow alignment during liquid crystal injection, the liquid crystal cell was heated to 120°C and then slowly cooled to room temperature. Polarizing plates were then attached to both outer surfaces of the substrates in the liquid crystal cell to obtain a liquid crystal display device. The above series of operations was also performed with a post-baking UV exposure dose of 100 to 10,000 J / m. 2 Three or more liquid crystal display elements with different amounts of ultraviolet light irradiation were manufactured by changing the exposure amount within the range of , and the liquid crystal display element with the exposure amount (optimum exposure amount) that showed the best alignment characteristics was used for the following evaluation.

[0139] 3. Evaluation of liquid crystal alignment (AC image retention characteristics) The liquid crystal display element manufactured in 2. above was measured for change in liquid crystal azimuth angle before and after 68 hours of operation at 55°C under backlight irradiation with an AC voltage of 11V using a birefringence meter (AXOMETRICS, AXOSTEP high-precision Mueller matrix imaging polarimeter). The evaluation was based on the following criteria: a change in liquid crystal azimuth angle of less than 0.1 degrees was rated "excellent (◎)," a change in liquid crystal azimuth angle of 0.1 degrees or more but less than 0.2 degrees was rated "good (○)," a change in liquid crystal azimuth angle of 0.2 degrees or more but less than 0.3 degrees was rated "fair (△)," and a change in liquid crystal azimuth angle of 0.3 degrees or more was rated "poor (×)." The smaller the change in liquid crystal azimuth angle, the less likely AC afterimages are to occur even when the liquid crystal display element is operated for a long period of time, and the better the liquid crystal alignment. As a result, this example was rated "excellent (◎)."

[0140] 4. Initial VHR Assessment The liquid crystal cell manufactured in 2 above was placed in a 60°C oven, and then the voltage holding ratio (VHR) was measured under conditions of 5V and 1670msec using a VHR measuring device "VHR-1" manufactured by Toyo Corporation. The evaluation criteria were as follows: if the VHR was higher than 95%, it was "excellent (◎)", if it was 95% or less but 90% or more, it was "good (○)", if it was less than 90% but 80% or more, it was "fair (△)", and if it was less than 80%, it was "poor (×)". As a result, the initial VHR of this example was evaluated as "excellent (◎)".

[0141] 5. Reliability Assessment The reliability of the liquid crystal cell manufactured in Section 2 above was evaluated. The evaluation was based on the voltage holding ratio as follows. First, a voltage of 5 V was applied to the liquid crystal cell for 60 microseconds, and the voltage holding ratio (VHR1) was measured 1670 milliseconds after the application was removed. Next, the liquid crystal cell was irradiated with an LED (backlight) at 60°C for two weeks, and then left to cool naturally at room temperature. After cooling, a voltage of 5 V was applied to the liquid crystal cell for 60 microseconds, and the voltage holding ratio (VHR2) was measured 1670 milliseconds after the application was removed. The measurement device used was a VHR measuring device "VHR-1" manufactured by Toyo Corporation. The rate of change in VHR (ΔVHR) at this time was calculated as the difference between VHR1 and VHR2 (ΔVHR = VHR1 - VHR2), and VHR reliability was evaluated based on ΔVHR. When ΔVHR was less than 10%, it was judged as "excellent (◎)", when it was 10% or more and less than 15%, it was judged as "good (○)", when it was 15% or more and 20% or less, it was judged as "fair (△)", and when it was more than 20%, it was judged as "poor (×)". As a result, the reliability of this example was "excellent (◎)".

[0142] 6. Evaluation of mechanical properties (rubbing resistance) The liquid crystal alignment agent (AL-1) prepared in step 1 above was applied to a glass substrate using a spinner and heated on a hot plate at 110°C for 2 minutes. This was then heated in a nitrogen-purged oven at 230°C for 30 minutes to form a coating film with an average thickness of 100 nm. This coating film was then photoaligned by irradiating the surface of the coating with linearly polarized ultraviolet light containing a 254 nm emission line using an Hg-Xe lamp at an optimal exposure dose from the substrate normal direction. The photoaligned coating film was then heat-treated in a nitrogen-purged oven at 230°C for 30 minutes, and the haze value of the coating film was measured using a haze meter. The coating film was then rubbed five times using a rubbing machine equipped with a roll wrapped in cotton cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / sec, and a pile depth of 0.3 mm. The haze value of the film was then measured using a haze meter, and the difference from the haze value before rubbing (haze change value) was calculated. If the haze value of the film before rubbing treatment is Hz1 (%) and the haze value of the film after rubbing treatment is Hz2 (%), the haze change value is expressed by the following mathematical formula (z-1): Haze change value (%) = Hz2-Hz1 …(z-1) When the haze change value of the film was less than 0.1%, it was evaluated as "excellent (◎)", when it was 0.1% or more but less than 0.2%, it was evaluated as "good (○)", when it was 0.2% or more but less than 0.3%, it was evaluated as "fair (△)", and when it was 0.3% or more, it was evaluated as "poor (×)". The smaller the haze change value, the higher the film strength and rubbing resistance, that is, the better the mechanical properties of the film. As a result, in this example, it was evaluated as "excellent (◎)".

[0143] [Examples 2 to 29 and Comparative Examples 1 to 5] A liquid crystal alignment agent was prepared in the same manner as in Example 1, except that the composition of the liquid crystal alignment agent was changed as shown in Table 3. Furthermore, using the obtained liquid crystal alignment agent, an FFS-type liquid crystal display element was manufactured by a photoalignment method in the same manner as in Example 1, and the liquid crystal alignment property, initial VHR, reliability, and mechanical properties were evaluated. The results are shown in Table 3. In Table 3, the numerical values ​​in the polymer column represent the blending ratio (parts by mass) of the solid content of each polymer relative to 100 parts by mass of the total amount of the polymer components used in preparing the liquid crystal alignment agent (the same applies to Table 4). [Table 3]

[0144] As shown in Table 3, the liquid crystal aligning agents of Examples 1 to 29 showed a good balance of improvements in liquid crystal alignment, initial VHR, reliability, and mechanical properties compared to the liquid crystal aligning agents of Comparative Examples 1 to 5, which did not contain a polymer using two or more types of tetracarboxylic dianhydrides including a specific acid dianhydride, and showed good results. Among these, Examples 1 to 4, 6, and 8 were all evaluated as "◎", and were particularly excellent.

[0145] [Example 30: Rubbed FFS-type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent Polymer components (solid content: 25 parts by mass of polymer (PA-9), 75 parts by mass of polymer (PA-21)) and 5 parts by mass of compound (Ad-3) were diluted with NMP, γ-butyrolactone (GBL), BC, and diacetone alcohol (DAA) to obtain a solution with a solvent composition of NMP / GBL / BC / DAA = 35 / 35 / 20 / 10 (mass ratio) and a solid content concentration of 3.5% by mass. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-30).

[0146] 2. Fabrication of FFS-type LCD elements using the rubbing method A first substrate and a second substrate similar to those in Example 1 were prepared. Next, a liquid crystal alignment agent (AL-30) was applied to the electrode-forming surface of the first substrate and one side of the second substrate using a spinner, and then heated (pre-baked) on a hot plate at 110°C for 3 minutes. This was followed by drying (post-baking) for 40 minutes in a nitrogen-purged 180°C oven to form a coating film with an average thickness of 100 nm. Next, the coating film surface was subjected to a rubbing treatment using a rubbing machine equipped with a roll wrapped around a rayon cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / sec, and a pile indentation length of 0.3 mm. This was followed by ultrasonic cleaning in ultrapure water for 1 minute and then drying for 10 minutes in a 100°C clean oven to obtain a pair of substrates with liquid crystal alignment films. Next, a pair of substrates with liquid crystal alignment films were screen-printed with an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres, leaving a liquid crystal injection port at the edge of the surface where the liquid crystal alignment film was formed. The substrates were then stacked and pressed together, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was filled into the gap between the pair of substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. To eliminate flow alignment during liquid crystal injection, the substrates were heated to 120°C and then slowly cooled to room temperature to produce a liquid crystal cell. When stacking the pair of substrates, the rubbing directions of each substrate were set antiparallel. Polarizing plates were then attached to both outer surfaces of the substrates in the liquid crystal cell to obtain an FFS-mode liquid crystal display device.

[0147] 3. Evaluation The liquid crystal display elements or liquid crystal cells manufactured in 2 above were evaluated for liquid crystal alignment, initial VHR, and reliability by the same methods as in Example 1. In addition, the mechanical properties (rubbing resistance) were evaluated by the following method. These results are shown in Table 4. [Evaluation of mechanical properties (rubbing resistance)] The liquid crystal alignment agent (AL-30) prepared in 1 above was applied to a glass substrate using a spinner and heated on a hot plate at 110°C for 2 minutes. The substrate was then heated in a nitrogen-purged oven at 180°C for 30 minutes to form a coating film with an average thickness of 100 nm. The haze value of the coating film was measured using a haze meter. Next, this coating film was subjected to a rubbing treatment five times in the same manner as in Example 1. The haze value of the film was then measured using a haze meter. The haze value of the film before the rubbing treatment was defined as Hz1 (%), and the haze value of the film after the rubbing treatment was defined as Hz2 (%). The haze change value (%) was calculated using the above formula (z-1). The calculated haze change value was also used to evaluate the mechanical properties of the film according to the same criteria as in Example 1.

[0148] [Examples 31 to 49 and Comparative Example 6] A liquid crystal alignment agent was prepared in the same manner as in Example 30, except that the composition of the liquid crystal alignment agent was changed as shown in Table 4. Using the obtained liquid crystal alignment agent, an FFS-type liquid crystal display element was manufactured by a rubbing method in the same manner as in Example 30, and the liquid crystal alignment property, initial VHR, reliability and mechanical properties were evaluated. The results are shown in Table 4.

[0149] [Table 4]

[0150] As shown in Table 4, the liquid crystal alignment agents of Examples 30 to 49 showed a good balance of improvements in liquid crystal alignment, initial VHR, reliability, and mechanical properties compared to the liquid crystal alignment agent of Comparative Example 6, which did not contain a polymer using two or more types of tetracarboxylic dianhydrides including a specific acid dianhydride, and showed good results.

[0151] From the above results, it has become clear that a liquid crystal alignment agent containing two or more polymers, at least one of which is a polymer using two or more tetracarboxylic dianhydrides including a specific acid dianhydride, can form a liquid crystal alignment film with excellent mechanical properties, and can obtain a liquid crystal element that exhibits good liquid crystal alignment properties, a high voltage holding ratio, and excellent reliability.

Claims

1. The polymer (A) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and is obtained using two or more tetracarboxylic acid derivatives including a compound represented by the following formula (1): A liquid crystal aligning agent that satisfies at least one of the following requirements 1 and 2: Requirement 1: The composition further contains a polymer (B) different from the polymer (A). Requirement 2: The polymer (A) contains two or more kinds. 【Chemical 1】 (In formula (1), Y １ and Y ２ are each independently a tetravalent organic group. １ is a divalent organic group.

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

3. At least one of the polymer (A) and the polymer (B) is １ -N(R １ )-* １ A partial structure represented by (wherein R １ is a hydrogen atom or a monovalent organic group. １ " represents a bond to an atom other than a hydrogen atom.) and a nitrogen-containing heterocycle. The liquid crystal aligning agent according to claim 1, comprising a polymer containing a structural unit derived from a diamine having at least one selected from the group consisting of a

4. At least one of the polymer (A) and the polymer (B) is —N(R ２ )- (wherein R ２ The liquid crystal aligning agent according to claim 1, comprising a polymer having:

5. The polymer (A) may be —N(R ２ 5. The liquid crystal aligning agent according to claim 4, comprising a polymer having a partial structure represented by the formula:

6. Y in the above formula (1) １ and Y ２ The liquid crystal aligning agent according to claim 1 , wherein

7. Y in the above formula (1) １ and Y ２ The liquid crystal aligning agent according to claim 1 , wherein

8. Y in the above formula (1) １ and Y ２ The liquid crystal aligning agent according to claim 7 , wherein has a cyclobutane ring structure.

9. The liquid crystal aligning agent according to claim 1 , wherein the polymer (A) is a polyamic acid.

10. The two or more tetracarboxylic acid derivatives include a compound represented by the formula (1) and a tetracarboxylic acid dianhydride different from the compound represented by the formula (1).

11. The liquid crystal aligning agent according to claim 10, wherein the tetracarboxylic dianhydride different from the compound represented by formula (1) has a cyclobutane ring structure.

12. A liquid crystal alignment film formed by the liquid crystal aligning agent according to any one of claims 1 to 11.

13. A liquid crystal device comprising the liquid crystal alignment film according to claim 12.

14. A method for producing a liquid crystal alignment film, comprising forming a coating film using the liquid crystal aligning agent according to any one of claims 1 to 11, and subjecting the coating film to an alignment treatment to impart liquid crystal aligning ability.

15. A compound represented by the following formula (3): 【Chemistry 2】 (In formula (3), Y １ and Y ２ are each independently a tetravalent organic group having an alicyclic structure. ２ is a divalent group having a linear structure in the main chain in which two or more atoms are linearly linked, or -A １ -N(R ３ )-A ２ - is. A １ and A ２ are each independently a substituted or unsubstituted phenylene group. ３ is a monovalent organic group.

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