CN116438220A

CN116438220A - Liquid crystal aligning agent, method for producing polymer, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: CN116438220A
Application number: CN202180077679.2A
Authority: CN
Inventors: 仲井崇
Original assignee: Nissan Chemical Corp
Current assignee: Nissan Chemical Corp
Priority date: 2020-11-19
Filing date: 2021-10-21
Publication date: 2023-07-14
Also published as: KR20230109658A; WO2022107541A1; JPWO2022107541A1; TW202229526A

Abstract

The invention provides a liquid crystal aligning agent which can obtain a liquid crystal aligning film with high voltage retention rate and reduce the risk of moisture absorption and whitening and has excellent mass production stability, and a liquid crystal display element with the liquid crystal aligning film. A liquid crystal aligning agent characterized by comprising the following component (A). Component (A): at least one polymer (A) selected from the group consisting of a copolymer having a repeating unit represented by the following formula (a), a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), and a polyimide which is an imide of the copolymer, wherein at least one of the repeating unit represented by the following formula (a), the repeating unit represented by the following formula (1) and the repeating unit represented by the following formula (2) has a divalent organic group represented by the following formula (EG).(regarding each substituent, as defined in the specification.)

Description

Liquid crystal aligning agent, method for producing polymer, liquid crystal alignment film, and liquid crystal display element

Technical Field

The invention relates to a liquid crystal aligning agent, a method for manufacturing a polymer, a liquid crystal alignment film and a liquid crystal display element.

Background

In the case of liquid crystal display elements used for liquid crystal televisions, navigation devices, smartphones, and the like, a liquid crystal alignment film for controlling the alignment state of liquid crystals is generally provided in the element. The liquid crystal alignment film has a function of controlling the alignment of liquid crystal molecules in a certain direction in a liquid crystal display element. For example, the liquid crystal display element has a structure in which liquid crystal molecules forming a liquid crystal layer are sandwiched between liquid crystal alignment films formed on the surfaces of a pair of substrates. Accordingly, the liquid crystal molecules are aligned in a certain direction by the liquid crystal alignment film, and respond by applying a voltage to an electrode provided between the substrate and the liquid crystal alignment film. As a result, the liquid crystal display element displays a desired image using the change in orientation due to the response of the liquid crystal molecules. As a liquid crystal alignment film, a polyimide-based liquid crystal alignment film has been mainly used, which is obtained by applying a liquid crystal alignment agent containing a polyimide precursor such as polyamide acid (polyamide acid) or a solution of a soluble polyimide as a main component to a glass substrate or the like and baking the applied liquid crystal alignment agent.

In recent years, a liquid crystal alignment film having a high voltage holding ratio for power saving of a liquid crystal display element in addition to excellent liquid crystal alignment properties has been demanded.

In order to meet the above-mentioned demand, patent document 1 proposes a liquid crystal aligning agent containing polyimide obtained by reacting a specific diamine component.

Prior art literature

Patent literature

Patent document 1: international publication No. 2019-082975

Disclosure of Invention

Problems to be solved by the invention

On the other hand, as a liquid crystal aligning agent containing polyimide, an organic polar solvent such as N-methylpyrrolidone or γ -butyrolactone is generally used. However, these solvents have a disadvantage of high hygroscopicity although they have high solubility. Therefore, when a liquid crystal aligning agent containing polyimide having low solubility in a high humidity environment is treated, there is a risk of moisture absorption and whitening such as precipitation of polyimide and whitening of film during coating, and thus there is a problem in terms of mass production stability.

In view of the above, an object of the present invention is to provide a liquid crystal aligning agent which can obtain a liquid crystal alignment film having a high voltage holding ratio and reduce the risk of wet whitening, and which is excellent in mass production stability, and a liquid crystal display element comprising the liquid crystal alignment film.

Solution for solving the problem

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a liquid crystal aligning agent containing a specific component is effective for achieving the above-mentioned object, and have completed the present invention.

The present invention has the following gist based on the above findings.

A liquid crystal aligning agent characterized by comprising the following component (A).

(A) The components are as follows: at least one polymer (A) selected from the group consisting of a copolymer having a repeating unit represented by the following formula (a), a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), and a polyimide which is an imide of the copolymer, wherein at least one of the repeating unit represented by the following formula (a), the repeating unit represented by the following formula (1) and the repeating unit represented by the following formula (2) has a divalent organic group represented by the following formula (EG).

( X represents a tetravalent organic group. Y represents a divalent organic group derived from diamine. Each of the two R's independently represents a hydrogen atom or a monovalent organic group. Each of two Z independently represents a hydrogen atom or a monovalent organic group. )

(A ₁ Is a divalent organic group, A _1’ Is a divalent organic group derived from diamine, C ₁ And C _1’ Each independently is a hydrogen atom or a monovalent organic group. )

(A ₂ Is a divalent organic group, A _2’ A divalent organic group obtained by removing hydrogen atoms contained in two hydroxyl groups from an organic diol. )

(R represents a hydrogen atom or a methyl group. N is an integer of 3 to 40.)

Effects of the invention

According to the liquid crystal aligning agent of the present invention, a liquid crystal alignment film having a high voltage holding ratio can be obtained, and a liquid crystal display element having the liquid crystal alignment film can be obtained. Further, a liquid crystal aligning agent having reduced risk of moisture absorption and whitening and excellent mass production stability can be obtained. Further, according to the liquid crystal aligning agent of the present invention, a liquid crystal display element with few display defects can be obtained.

The mechanism for obtaining the above-described effects of the present invention is not necessarily clear, but is estimated as follows. That is, it is considered that the above-described effect is obtained by introducing urea groups and urethane groups into the polymer to generate hydrogen bonds of appropriate strength, thereby improving voltage holding characteristics, and introducing hydrophilic polyethylene glycol chains into the polymer to improve water solubility.

Detailed Description

Hereinafter, each component contained in the liquid crystal aligning agent of the present disclosure and other components optionally blended as needed will be described. In the present specification, examples of the halogen atom include: fluorine atom, chlorine atom, bromine atom, iodine atom.

< Polymer (A) >)

The liquid crystal aligning agent of the present invention is at least one polymer (a) selected from the group consisting of a copolymer (hereinafter, also referred to as a polyimide precursor (a)) having a repeating unit represented by the above formula (a), a repeating unit represented by the above formula (1) and a repeating unit represented by the above formula (2), and a polyimide which is an imide of the copolymer, and at least one of the repeating unit represented by the above formula (a), the repeating unit represented by the above formula (1) and the repeating unit represented by the above formula (2) has a divalent organic group represented by the above formula (EG).

In the above formula (EG), the upper limit value of n is preferably 40, more preferably 30, and particularly preferably 20, from the viewpoint of improving the liquid crystal alignment property. The lower limit value of n is preferably 3, more preferably 4, from the viewpoint of improving the liquid crystal alignment property.

(repeating units represented by the formula (a))

In the above formula (a), Y represents a divalent organic group derived from diamine. The following diamines are examples of the diamine. The diamine may be used alone or in combination of two or more.

A diamine represented by the following formula (O); diamines having photo-alignment groups such as 4,4' -diaminoazobenzene and diaminodiphenylacetylene; diamines having an amide bond or a urea bond such as diamines represented by the following formulas (h-1) to (h-6); 3,3' -diaminodiphenylmethane, 3,4' -diaminodiphenylmethane, 4' -diaminobenzophenone, 1, 4-bis (4-aminophenyl) benzene, 1, 3-bis (4-aminophenyl) benzene, 1, 4-bis (4-aminobenzyl) benzene, the following formula (d) _o ) The diamines shown; a diamine having at least one nitrogen atom-containing structure (hereinafter, also referred to as a specific nitrogen atom-containing structure) selected from the group consisting of a nitrogen atom-containing heterocycle, a secondary amino group, and a tertiary amino group; 2, 4-diaminophenol, 3, 5-diaminobenzyl alcohol, 2, 4-diaminobenzyl alcohol, 4, 6-diaminoresorcinol; 4,4' -Di Diamines having a carboxyl group such as amino-3, 3' -dihydroxybiphenyl, 2, 4-diaminobenzoic acid, 2, 5-diaminobenzoic acid, 3, 5-diaminobenzoic acid, and diamines represented by the following formulas (3 b-1) to (3 b-4); 4- (2- (methylamino) ethyl) aniline, 4- (2-aminoethyl) aniline, 1- (4-aminophenyl) -1, 3-trimethyl-1H-indan-5-amine, 1- (4-aminophenyl) -2, 3-dihydro-1, 3-trimethyl-1H-inden-6-amine; diamines having a photopolymerizable group at the terminal such as 2- (2, 4-diaminophenoxy) ethyl methacrylate and 2, 4-diamino-N, N-diallylaniline; diamines having a steroid skeleton such as cholesteryl-3, 5-diaminobenzene, cholesteryloxy-2, 4-diaminobenzene, 3, 5-diaminobenzoate cholesteryl ester, 3, 5-diaminobenzoate lanostanyl ester, and 3, 6-bis (4-aminobenzoyloxy) cholestane; diamines represented by the following formulas (V-1) to (V-6); diamines having a group "-N (D) -" (D represents a protecting group which is detached and substituted with a hydrogen atom by heating, preferably t-butoxycarbonyl group) such as the following formulae (5-1) to (5-11); diamines having a siloxane bond, such as 1, 3-bis (3-aminopropyl) -tetramethyldisiloxane and a diamine represented by the following formula (Ds-1); diamines having an oxazoline structure, such as the following formulas (Ox-1) to (Ox-2); and diamines having two amino groups bonded to any of the groups represented by formulas (Y-1) to (Y-167) described in International publication No. 2018/117239), such as m-xylylenediamine, 1, 3-propane diamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1, 3-bis (aminomethyl) cyclohexane, 1, 4-diaminocyclohexane, 4' -methylenebis (cyclohexylamine), and the like.

(Ar represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring; two Ar's are optionally the same or different, and any hydrogen atom in the above benzene ring, biphenyl structure, or naphthalene ring is optionallySubstituted with monovalent groups. p is an integer of 0 or 1. Q (Q) ₂ Represents- (CH) ₂ ) _n - (n is an integer of 2 to 18), or the- (CH) ₂ ) _n -CH of ₂ -a group in which at least a part of the group is substituted with any one of-O-, -C (=o) -or-O-C (=o) -. Wherein at Q ₂ In the case of ether bond, Q ₂ The total number of all the ether bonds is 3 or less. )

(A plurality of m are optionally each the same or different.)

(in the formula (3 b-1), A ¹ Represents a single bond, -CH ₂ －、－C ₂ H ₄ －、－C(CH ₃ ) ₂ －、－CF ₂ －、－C(CF ₃ ) ₂ －、－O－、－CO－、－NH－、－N(CH ₃ )－、－CONH－、－NHCO－、－CH ₂ O－、－OCH ₂ －、－COO－、－OCO－、－CON(CH ₃ ) -or-N (CH) ₃ ) CO-, m1 and m2 are each independently an integer of 0 to 4, and m1+m2 is an integer of 1 to 4. In the formula (3 b-2), m3 and m4 are each independently an integer of 1 to 5. In the formula (3 b-3), A ² Represents a linear or branched alkyl group having 1 to 5 carbon atoms, and m5 is an integer of 1 to 5. In the formula (3 b-4), A ³ And A ⁴ Each independently represents a single bond, -CH ₂ －、－C ₂ H ₄ －、－C(CH ₃ ) ₂ －、－CF ₂ －、－C(CF ₃ ) ₂ －、－O－、－CO－、－NH－、－N(CH ₃ )－、－CONH－、－NHCO－、－CH ₂ O－、－OCH ₂ －、－COO－、－OCO－、－CON(CH ₃ ) -or N- (CH) ₃ ) CO-, and m6 is an integer of 1 to 4. )

(X ^v1 ～X ^v4 、X ^p1 ～X ^p2 Each independently represents- (CH) ₂ ) _a - (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH) ₃ )－、－NH－、－O－、－CH ₂ O－、－CH ₂ OCO-, -COO-, or-OCO-, X ^v5 represents-O-, -CH ₂ O－、－CH ₂ OCO-, -COO-, or-OCO-. Xa represents a single bond, -O-, -NH-, or-O- (CH) ₂ ) _m -O- (m represents an integer from 1 to 6), R ^v1 ～R ^v4 、R ^1a ～R ^1b Each independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. In formula (V-6), two k are optionally the same or different. )

(Boc represents tert-butoxycarbonyl.)

As the above formula (d) _o ) The diamine shown in the following formula (d) is preferable from the viewpoint of improving the liquid crystal alignment property _o －1)～(d _o -6) diamines, 3' -diaminodiphenyl ether, 3,4' -diaminodiphenyl ether and 4,4' -diaminodiphenyl ether.

In the diamine represented by the above formula (O), any hydrogen atom in the benzene ring, the biphenyl structure, or the naphthalene ring is optionally substituted with a monovalent group. Examples of the monovalent group include: halogen atom, alkyl group having 1 to 10 carbon atoms, alkenyl group having 2 to 10 carbon atoms, alkoxy group having 1 to 10 carbon atoms, fluoroalkyl group having 1 to 10 carbon atoms, fluoroalkenyl group having 2 to 10 carbon atoms, fluoroalkoxy group having 1 to 10 carbon atoms, alkyloxycarbonyl group having 1 to 10 carbon atoms, cyano group, nitro group, and the like.

The diamine represented by the formula (O) is preferably a diamine represented by the following formulas (O-1) to (O-16) from the viewpoint of improving the alignment property of liquid crystals.

(in the formula (o-14), two m may be the same or different.)

Examples of the nitrogen atom-containing heterocyclic ring that the diamine having a specific nitrogen atom-containing structure may have include: pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, isoquinoline, naphthyridine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, hexamethyleneimine, and the like. Among them, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, or acridine are preferable.

The secondary amino group and the tertiary amino group that the diamine having a specific nitrogen atom structure may have are represented by, for example, the following formula (n).

In the above formula (n), R represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. "means a bond to a hydrocarbon group, at least one bond to an aromatic hydrocarbon group.

Examples of the monovalent hydrocarbon group of R in the formula (n) include: alkyl groups such as methyl, ethyl, and propyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl and methylphenyl. R is preferably a hydrogen atom or a methyl group.

Specific examples of the diamine having a specific nitrogen atom-containing structure include: 2, 6-diaminopyridine, 3, 4-diaminopyridine, 2, 4-diaminopyrimidine, 3, 6-diaminocarbazole, N-methyl-3, 6-diaminocarbazole, 1, 4-bis- (4-aminophenyl) -piperazine, 3, 6-diaminoacridine, N-ethyl-3, 6-diaminocarbazole, N-phenyl-3, 6-diaminocarbazole, diamines represented by the following formulas (Dp-1) to (Dp-8), and diamines represented by the following formulas (z-1) to (z-18).

In the case where the repeating unit (a) has a divalent organic group represented by the above formula (EG), it is preferable that at least one of the above X, Y has a divalent organic group represented by the above formula (EG). In the case where Y has a divalent organic group represented by the formula (EG), examples of Y include divalent organic groups derived from a diamine having amino groups at both ends of the divalent organic group represented by the formula (EG) with an aromatic group interposed therebetween. Examples of the aromatic group include a benzene ring, a biphenyl structure, and a naphthalene ring. More preferably, Y is derived from the following formula (d) _EG ) The divalent organic groups of the diamines shown.

Ar each independently represents a divalent aromatic group or a condensed ring group, optionally the same or different. More than one hydrogen atom on the aromatic or condensed ring group is optionally substituted with a monovalent group. Specific examples of Ar include benzene rings, biphenyl structures, and naphthalene rings. Examples of the monovalent group include: halogen atom, alkyl group having 1 to 10 carbon atoms, alkenyl group having 2 to 10 carbon atoms, alkoxy group having 1 to 10 carbon atoms, fluoroalkyl group having 1 to 10 carbon atoms, fluoroalkenyl group having 2 to 10 carbon atoms, fluoroalkoxy group having 1 to 10 carbon atoms, carboxyl group, hydroxyl group, alkyloxycarbonyl group having 1 to 10 carbon atoms, cyano group, nitro group, etc. n represents an integer of 3 to 40. The upper limit of n is preferably 30, more preferably 20.

In the present specification, the "aromatic group" having a valence of m "means a group having m hydrogen atoms removed from a ring portion of an aromatic ring. The "condensed ring group" of valence m refers to a group of valence m obtained by removing m hydrogen atoms from the ring portion of the condensed ring.

The above Y is preferably a divalent organic group derived from a diamine selected from the group consisting of a diamine represented by the above formula (O), a diamine having an amide bond or a urea bond, 3' -diaminodiphenylmethane, 3,4' -diaminodiphenylmethane, 4' -diaminobenzophenone, 1, 4-bis (4-aminophenyl) benzene, 1, 3-bis (4-aminophenyl) benzene, 1, 4-bis (4-aminobenzyl) benzene, and the above formula (d) _o ) Diamines of the formula (D), diamines of the formula (I), 4- (2- (methylamino) ethyl) aniline, 4- (2-aminoethyl) aniline, diamines having the group "-N (D) -" (D represents a protecting group which is detached by heating and is substituted by a hydrogen atom, preferably tert-butoxycarbonyl group) _EG ) The diamines shown are in the group of diamines. By satisfying the above-described Y, it is preferable to obtain an effect of reducing the pretilt angle of the liquid crystal, reducing the afterimage caused by long-term ac driving, and improving the relaxation property of the accumulated charge.

In the above formula (a), X represents a tetravalent organic group. X preferably represents a tetravalent organic group derived from a tetracarboxylic dianhydride or a derivative thereof. The tetravalent organic group may be: a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or a derivative thereof, a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride or a derivative thereof, or a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride or a derivative thereof.

Here, the acyclic aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. The aromatic hydrocarbon compound may have an alicyclic structure or an aromatic ring structure in a part thereof, without being composed of only a chain hydrocarbon structure. The alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an alicyclic structure. Wherein none of the four carboxyl groups is bonded to an aromatic ring. Further, the structure need not be composed of only an alicyclic structure, and may have a chain hydrocarbon structure or an aromatic ring structure in a part thereof. The aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an aromatic ring. The derivatives of the tetracarboxylic dianhydride include: a tetracarboxylic dihalide, a tetracarboxylic dialkyl ester, or a tetracarboxylic dialkyl ester dihalide.

The tetracarboxylic dianhydride or its derivative may be used alone or in combination of two or more.

Among these, the acyclic aliphatic or alicyclic tetracarboxylic dianhydride or a derivative thereof is preferably a tetracarboxylic dianhydride having at least one partial structure selected from the group consisting of a cyclobutane ring structure, a cyclopentane ring structure and a cyclohexane ring structure, or a derivative thereof, from the viewpoint of improving the liquid crystal alignment property.

The above X is preferably a tetravalent organic group derived from a tetracarboxylic dianhydride represented by the following formula (t) or a derivative thereof.

Wherein X is ₁ Is selected from the structures of the following formulas (X1-1) to (X1-25). * Representing a bond.

In the formulae (X1-1) to (X1-4), R ₁ ～R ₂₁ Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. * Representing a bond. R is from the viewpoint of improving the orientation of the liquid crystal ₁ ～R ₂₁ Preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, more preferably a hydrogen atom, or a methyl group.

In the formulae (X1-24) to (X1-25), j and k are integers of 0 or 1, A ₁ And A ₂ Each independently represents a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or amide. Multiple A ₂ Optionally each being the same or different.

Specific examples of the formula (X1-1) include the following formulas (1-1) to (1-6). From the viewpoint of improving the liquid crystal alignment, the formulas (1-1) and (1-2) are particularly preferable. * As defined above.

As preferable specific examples of the above-mentioned formulas (X1-24) and (X1-25), the following formulas (X1-26) to (X1-41) are given. * As defined above.

/>

From the viewpoint of improving the orientation of the liquid crystal, X is as follows ₁ Preferably, the above formulae (X1-1) to (X1-10), (X1-18) to (X1-23), (X1-24) to (X1-25), or (X1-26) to (X1-30), more preferably, the above formulae (X1-1), (X1-5), (X1-7) to (X1-10), (X1-21), and,(X1-23), (X1-24) to (X1-25), or (X1-26) to (X1-30), more preferably the above formula (1-1), (1-2), (X1-5), (X1-7), (X1-9), or (X1-26) to (X1-30).

As described above, in the case where the repeating unit (a) has a divalent organic group represented by the above formula (EG), it is preferable that at least one of the above X, Y has a divalent organic group represented by the above formula (EG). In the case where X has a divalent organic group represented by the formula (EG), examples of X include: tetravalent organic groups derived from tetracarboxylic dianhydrides or derivatives thereof shown below.

Examples of the monovalent organic group in R, Z in the formula (a) include: monovalent hydrocarbon groups having 1 to 20 carbon atoms, represented by-O-; -S-, -CO-, -COO-, -COS-, -NR ³ - (wherein R ³ Is hydrogen atom or monovalent hydrocarbon group having 1 to 10 carbon atoms), -CO-NR ³ - (wherein R ³ Is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms), -Si (R) ³ ) ₂ - (wherein R ³ Is hydrogen atom or monovalent hydrocarbon group with 1-10 carbon atoms), -SO ₂ A monovalent group a obtained by substituting a methylene group of the hydrocarbon group, a monovalent group obtained by substituting at least one of a monovalent hydrocarbon group or a hydrogen atom bonded to a carbon atom of the monovalent group a with a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), a hydroxyl group, an alkoxy group, a nitro group, an amino group, a mercapto group, a nitroso group, an alkylsilane group, an alkoxysilane group, a silanol group, a sulfinyl group, a phosphine group, a carboxyl group, a cyano group, a sulfo group, an acyl group, etc., and a monovalent group having a heterocycle. Among them, the monovalent organic group in R, Z in the above formula (a) is preferably an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a t-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group, more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably a methyl group.

From the viewpoint of obtaining the effect of the present invention, R and Z are each independently preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group.

In the above formula (a), X, Y, R, Z are each optionally one or two or more.

(repeating unit represented by the formula (1))

In the above formula (1), A ₁ Is a divalent organic group. As A ₁ Examples of (2) include divalent organic groups derived from diisocyanates. The diisocyanate may be used alone or in combination of two or more.

Here, examples of the diisocyanate include: aromatic diisocyanates and aliphatic diisocyanates.

As used herein, "aromatic diisocyanate" refers to a diisocyanate having at least one aromatic group. Further, "aliphatic diisocyanate" refers to a diisocyanate having an aliphatic group and no aromatic group.

As A ₁ Examples include: (i) Divalent organic groups derived from aromatic diisocyanates, in the diisocyanate structure (o=c=n-R-n=c=o), R is an organic group having 6 to 30 carbon atoms with at least one benzene ring; or (ii) a divalent organic group derived from an aliphatic diisocyanate, wherein in the diisocyanate structure (o=c=n—r—n=c=o), R is an organic group having 4 to 30 carbon atoms and having no aliphatic group.

The aliphatic group includes any one of an acyclic aliphatic group and an alicyclic group.

As A ₁ Specific examples of (a) include: derived from ortho-phenylene diisocyanate, meta-phenylene diisocyanate, para-phenylene diisocyanate, toluene diisocyanate (e.g., 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate), 1, 4-diisocyanate-2-methoxybenzene, 2, 5-diisocyanate xylenes, 3 '-dimethyl-4, 4' -biphenyl diisocyanate, 4 '-diisocyanate diphenyl ether, 2' -bis (4-diisocyanate phenyl) propane, 4Divalent organic groups of aromatic diisocyanates such as'-diisocyanate diphenylmethane (4, 4' -diphenylmethane diisocyanate), 4 '-diisocyanate diphenyl ether, 4' -diisocyanate diphenyl sulfone, 3 '-diisocyanate diphenyl sulfone, and 2,2' -diisocyanate benzophenone; divalent organic groups derived from aliphatic diisocyanates such as isophorone diisocyanate, norbornene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and tetramethylene diisocyanate.

In the above formula (1), A _1’ Is a divalent organic group derived from a diamine. The diamine may be exemplified by the diamine exemplified by the repeating unit (a), and the preferable embodiment is the same as the diamine.

In the case where the above formula (1) has a divalent organic group represented by the above formula (EG), the above A is preferable ₁ And A _1’ At least one of them has a divalent organic group represented by the above formula (EG).

The above A _1’ In the case of a divalent organic group represented by the above formula (EG), A is _1’ Specific structures of (a) may be: the divalent organic group derived from a diamine having the divalent organic group represented by the above formula (EG) as exemplified by the above repeating unit (a), or a preferable embodiment thereof.

The above A ₁ In the case of a divalent organic group represented by the above formula (EG), A is as described above ₁ Examples include: divalent organic groups derived from diisocyanates as shown below.

As C in the above formula (1) ₁ 、C _1’ Examples of the monovalent organic group (a) include a structure exemplified by R, Z of the repeating unit (a). From the viewpoint of obtaining the effects of the present invention, C ₁ And C _1’ Each independently is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group 。

In the above formula (1), A ₁ 、A _1’ 、C ₁ 、C _1’ Optionally one or more of each.

(repeating units represented by the formula (2))

In the above formula (2), A ₂ Is a divalent organic group. As the A ₂ Examples of (1) include divalent organic groups derived from diisocyanates, and examples of (A) in the repeating unit (1) include ₁ The structures shown by way of example, the preferred embodiment is also described in connection with A ₁ The same applies.

In the above formula (2), A _2’ A divalent organic group obtained by removing hydrogen atoms contained in two hydroxyl groups from an organic diol. The organic diol may be used alone or in combination of two or more. The organic diols include: a diol comprising a divalent organic group represented by the above formula (EG); alkylene glycols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1, 3-propanediol, 1, 3-butanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, 1, 8-octanediol, 2-methyl-1, 8-octanediol, 1, 9-nonanediol, 1, 10-decanediol, 1, 4-cyclohexanediol, and 1, 4-cyclohexanedimethanol; carboxyl group-containing diols such as dimethylolpropionic acid (2, 2-bis (hydroxymethyl) propionic acid), dimethylolbutyric acid (2, 2-bis (hydroxymethyl) butyric acid), 2, 3-dihydroxybenzoic acid, 2, 4-dihydroxybenzoic acid, 2, 5-dihydroxybenzoic acid, 2, 6-dihydroxybenzoic acid, 3, 4-dihydroxybenzoic acid, and 3, 5-dihydroxybenzoic acid; polytetramethylene glycol; random copolymers of tetramethylene glycol with neopentyl glycol; polyester diol obtained by reacting a polyhydric alcohol with a polybasic acid; a polycarbonate diol having a carbonate skeleton; polycaprolactone diol obtained by ring-opening addition reaction of lactones such as gamma-butyrolactone, epsilon-caprolactone and delta-valerolactone; bisphenol a; ethylene oxide adducts of bisphenol a; propylene oxide adducts of bisphenol a; hydrogenating bisphenol a; hydrogenating the ethylene oxide adduct of bisphenol a; propylene oxide adducts of hydrogenated bisphenol A, and the like.

The diol containing a divalent organic group represented by the formula (EG) is not particularly limited as long as the formula (EG) is contained in the molecule, and a diol having hydrogen atoms bonded to both ends of the formula (EG) is preferable. In the diols having hydrogen atoms bonded to both ends of the above formula (EG), the upper limit of n is preferably 40, more preferably 30, and particularly preferably 20, from the viewpoint of improving the liquid crystal alignment property. The lower limit value of n is preferably 3, more preferably 4, from the viewpoint of improving the liquid crystal alignment property. More specifically, the diols containing the divalent organic group represented by the above formula (EG) include tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, and the trade names PEG-300, PEG-400, PEG-600, PEG-1000, PEG-1500, PEG-2000, PEG-4000N, PEG-4000S, PEG-6000E, PEG-6000P, PEG-10000, PEG-13000, and PEG-20000 manufactured by Sanyo chemical industry Co., ltd; product names PEG300, PEG1000, PEG2000, PEG4000, PEG6000, PEG8000, PEG10000, PEG12000, PEG20000, and PEG35000 manufactured by Merck company; product numbers P2139, P3265, P3515, 81210, 81240, 81260, 81285, 81310, 181986, 181994, 182001, 182028, 189456, 202304, 202312, 202320, 202339, 202398, 202421, 202436, 202444, 202452, 295906, 309028, 372773, 372781, 373001, 412325, 435406, 435422, 435457, 637726, manufactured by SIGMA-ALDRICH company; trade names of SINOPLPEG 600, SINOPLPEG 1500, and SINOPLPEG 4000 manufactured by Zhongri synthetic chemical Co., ltd; trade names peg#300, peg#400, peg#600, peg#1000, peg#1500, peg#1540, peg#4000, peg#6000M, polyethylene glycol represented by commercial products of tokyo chemical industry company under product names Polyethylene Glycol 400, polyethylene Glycol 600, tripropylene glycol, tetrapropylene glycol, polypropylene glycol (more preferably polypropylene glycol having an average molecular weight of 300 to 10000), and copolymers of ethylene oxide and propylene oxide having an average molecular weight of 200 to 5000. The polyethylene glycol and polypropylene glycol may be obtained by anionic ring-opening polymerization of ethylene oxide and propylene oxide. The polymerization reaction may be carried out using a polymerization initiator (e.g., water, ethylene glycol, propylene glycol, etc.) and a catalyst amount of a base (e.g., potassium hydroxide). Preferable specific examples of the diol having hydrogen atoms bonded to both ends of the above formula (EG) include: tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, trade names PEG-300, PEG-400, PEG-600, PEG-1000, product names PEG300, PEG1000, PEG #300, PEG #400, PEG #600, PEG #100, PEG # Polyethylene Glycol, polyethylene Glycol 600, PEG #100, and PEG SPECIALTY CHEMICALS.

The average molecular weight of the diol shown by way of example among the diols containing the divalent organic group shown in (EG) above refers to the weight average molecular weight based on polystyrene obtained by Gel Permeation Chromatography (GPC).

In the case where the above formula (2) has a divalent organic group represented by the above formula (EG), the above A is preferable ₂ And A _2’ At least one of them has a divalent organic group represented by the above formula (EG).

The above A ₂ In the case of a divalent organic group represented by the above formula (EG), A is ₂ Specific structures of (a) may be: the repeating unit (1) is exemplified by a divalent organic group derived from a diisocyanate having a divalent organic group represented by the formula (EG).

The above A _2’ In the case of a divalent organic group represented by the above formula (EG), A is _2’ Specific structures of (a) may be: the divalent organic group containing the divalent organic group represented by the formula (EG) described in detail above is obtained by removing hydrogen atoms contained in two hydroxyl groups from a diol.

In the above formula (2), A ₂ 、A _2’ Optionally one or more of each.

(repeating units constituting the Polymer (A))

The polymer (a) in the present invention is at least one polymer selected from the group consisting of a copolymer having a repeating unit represented by the above formula (a), a repeating unit represented by the above formula (1) and a repeating unit represented by the above formula (2), and polyimide which is an imide of the copolymer (wherein at least one of the repeating unit represented by the above formula (a), the repeating unit represented by the above formula (1) and the repeating unit represented by the above formula (2) has a divalent organic group represented by the above formula (EG)). The polymer (a) may have a repeating unit represented by the above formula (a), a repeating unit represented by the above formula (1), a repeating unit represented by the above formula (2), and a terminal group.

The term "terminal group" as used herein means a group bonded to the terminal of the repeating unit constituting the polymer (A). Examples of the terminal group include: amino, carboxyl, anhydride, isocyanate or derivatives thereof. The amino group, carboxyl group, acid anhydride group, and isocyanate group are obtained by a general condensation reaction, and the above-mentioned derivative can be obtained by, for example, modifying a terminal group with a blocking agent as described below.

The content of the repeating unit represented by the formula (a) is preferably 2 to 98 mol%, more preferably 10 to 96 mol%, of the entire repeating unit constituting the polymer (a).

The content of the repeating unit represented by the formula (1) is preferably 1 to 49 mol%, more preferably 2 to 45 mol%, of the entire repeating unit constituting the polymer (a).

The content of the repeating unit represented by the formula (2) is preferably 1 to 49 mol%, more preferably 2 to 45 mol%, of the entire repeating unit constituting the polymer (a).

< Polymer (B) >)

From the viewpoint of improving electrical characteristics, the liquid crystal aligning agent of the present invention may further contain a polymer (B) different from the polymer (a), and the polymer (B) is at least one polymer selected from the group consisting of a polyimide precursor and an imidized polymer thereof.

The polymer (B) is preferably at least one polymer selected from the group consisting of polyimide precursors having a repeating unit represented by the following formula (B) and imidized polymers thereof.

(X _b Represents a tetravalent organic group. Y is Y _b Represents a divalent organic group. Two R _b Each independently represents a hydrogen atom, or a monovalent organic group. Two Z _b Each independently represents a hydrogen atom, or a monovalent organic group. )

The polymer (B) preferably does not have at least one selected from the group consisting of the repeating unit represented by the above formula (1) and the repeating unit represented by the above formula (2).

As X _b Examples of the tetravalent organic group in (a) include: specific examples of the tetravalent organic group derived from acyclic aliphatic tetracarboxylic dianhydride, the tetravalent organic group derived from alicyclic tetracarboxylic dianhydride, or the tetravalent organic group derived from aromatic tetracarboxylic dianhydride include X of the above formula (a) ₁ Tetravalent organic groups are shown by way of example. From the viewpoint of efficiently obtaining the effect of the present invention, tetravalent organic groups represented by the above formulas (X1-1) to (X1-25) (these are also collectively referred to as specific tetravalent organic groups) are preferable.

From the viewpoint of efficiently obtaining the effect of the present invention, the polymer (B) preferably contains 5 mol% or more of X of all the repeating units contained in the polymer (B) _b More preferably, the repeating unit of the specific tetravalent organic group contains 10 mol% or more of X of all repeating units contained in the polymer (B) _b Is a repeating unit of the above specific tetravalent organic group.

As Y _b Specific examples of (a) include divalent organic groups derived from diamines exemplified as the above polymer (a). From the viewpoint of improving electrical characteristics, the polymer (B) is preferably a polymer comprising a repeating unit, the repeating unit being Y _b Is selected from the group consisting of diamines having a specific nitrogen atom-containing structure, 2, 4-diaminophenol, 3, 5-diaminobenzyl alcohol, 2, 4-diaminobenzyl alcohol, 4, 6-diaminoresorcinol, 2, 4-diaminobenzoic acid, 2, 5-diaminobenzoic acid, 3, 5-diaminobenzoic acid, and the above formula (3 b-1) Divalent organic groups (also collectively referred to as specific divalent organic groups) in the group consisting of divalent organic groups obtained by removing two amino groups from a diamine having a carboxyl group, such as a diamine compound represented by the formula (3 b-4).

From the viewpoint of improving electrical characteristics, the polymer (B) may contain Y in an amount of 1 mol% or more of all the repeating units contained in the polymer (B) _b The repeating unit of the specific divalent organic group may contain Y in an amount of 5 mol% or more of all the repeating units contained in the polymer (B) _b Is a repeating unit of the above specific divalent organic group.

From the viewpoint of improving electrical characteristics, the content ratio of the component (A) to the component (B) may be 10/90 to 90/10, may be 20/80 to 90/10, or may be 20/80 to 80/20 in terms of the mass ratio of [ (A) component ]/[ (B) component ].

< production of Polymer (A) and Polymer (B) >)

The polyimide precursor (a) as the polymer (a) can be produced, for example, by a method comprising the steps of: a terminal isocyanate compound is synthesized by reacting a component (o) containing an organic diol having two hydroxyl groups in the molecule with a component (a) containing a compound having two isocyanate groups in the molecule, a terminal amine urea oligomer is synthesized by reacting a component (b) containing a compound having two primary or secondary amino groups in the molecule, and a component (c) containing a tetracarboxylic dianhydride or a derivative thereof. Wherein at least one of the compounds constituting the above-mentioned component (o), component (a), component (b) and component (c) has a partial structure represented by the following formula (EG) in the molecule.

(R represents a hydrogen atom or a methyl group. N is an integer of 3 to 40.)

On the other hand, the polyimide precursor (a) can also be produced by: the method comprises a step of reacting a component (a) with a component (b) to obtain a terminal isocyanate compound; and a step of reacting the component (o) with the component (c) to obtain a terminal diol compound, and then reacting the obtained terminal isocyanate compound with the terminal diol compound.

The polyimide precursor (a) can also be produced by: the method comprises a step of reacting the component (b) with the component (c) to obtain an amine-terminated amic acid oligomer or derivative thereof, a step of adding the component (o) thereto to prepare a mixed solution, and a step of further reacting the component (a).

The component (o), the component (a), the component (b) and the component (c) are each optionally one or two or more.

As the component (o), for example, an organic diol exemplified by the repeating unit represented by the above formula (2) may be mentioned, and "H-A" may be mentioned _2’ －H”(A _2’ And A in formula (2) _2’ The same) diol compounds shown.

Examples of the component (A) include o=c=n—A ₁ －N＝C＝O(A ₁ And A in formula (1) ₁ The same) of the diisocyanate compounds shown.

Examples of the component (b) include diamines represented by the following formula (mb).

(in the formula (mb), C ₁ 、C _1’ 、A _1’ And C in formula (1) ₁ 、C _1’ 、A _1’ The same applies. )

Specific examples of the compound represented by the above formula (mb) include: diamines are exemplified by the repeating units represented by the above formula (a).

Examples of the tetracarboxylic dianhydride or derivative thereof contained in the component (c) include: a tetracarboxylic dianhydride represented by the following formula (mc) or a derivative thereof (tetracarboxylic dihalide, a dialkyl tetracarboxylic ester, or a dialkyl tetracarboxylic ester dihalide).

(in the formula (mc), X is the same as X in the above formula (a))

More specifically, X in the above formula (mc) may be: a tetravalent organic group derived from a non-cyclic aliphatic tetracarboxylic dianhydride or a derivative thereof, a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride or a derivative thereof, or a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride or a derivative thereof, which are exemplified as the repeating unit represented by the above formula (a). Among them, tetracarboxylic dianhydride having at least one partial structure selected from the group consisting of a cyclobutane ring structure, a cyclopentane ring structure and a cyclohexane ring structure, or derivatives thereof are preferable from the viewpoint of high liquid crystal alignment. Among the tetracarboxylic dianhydrides or derivatives thereof contained in the component (c), the tetracarboxylic dianhydride or derivatives thereof represented by the above formula (t) are preferable.

The tetracarboxylic dianhydride represented by the formula (t) or a derivative thereof is preferably 1 mol% or more of the entire component (c). More preferably 5 mol% or more, and particularly preferably 10 mol% or more.

In the case where at least one of the compounds constituting the above (o), the (a), the (b) and the (c) components has a partial structure represented by the above formula (EG) in the molecule, "H-A _2’ A in the diol compound represented by-H' _2’ 、O＝C＝N－A ₁ A in the diisocyanate compound represented by n=c=o ₁ A in the diamine represented by the above formula (mb) _1’ At least one of X in the tetracarboxylic dianhydride represented by the formula (mc) has a partial structure represented by the formula (EG) in the molecule. Preferred specific examples thereof are as described above.

The reaction of the component (o), the component (a), the component (b) and the component (c) is usually carried out in an organic solvent. The organic solvent used in this case is not particularly limited as long as it is a solvent that dissolves the polyimide precursor to be produced. As specific examples, there may be mentioned: n, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methyl-epsilon-caprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethylphosphoric triamide, gamma-butyrolactone, isopropanol, methoxymethylpentanol, dipentene, ethylpentanyl ketone, methylnonyl ketone, methylethyl ketone, methylisopentyl ketone, methylisopropyl ketone, methylcellosolve, ethylcellosolve, methylcellosolve acetate, ethylcellosolve acetate, butylcarbitol, ethylcarbitol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol t-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethylisobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, 1, 4-dioxane, N-hexane, N-pentane, N-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, N-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diethylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, and the like. They may be used alone or in combination. The solvent may be a solvent which does not dissolve the polyimide precursor, or may be used in combination with the solvent in such a range that the polyimide precursor to be produced does not precipitate. Further, since moisture in the organic solvent causes inhibition of polymerization reaction and further hydrolysis of the polyimide precursor to be produced, it is preferable to use a dehydrated and dried organic solvent as the organic solvent.

Method for synthesizing terminal isocyanate Compound

The method for synthesizing a terminal isocyanate compound, which is obtained by reacting a component (o) containing an organic diol used in the present invention with a component (a) containing a diisocyanate compound having two isocyanate groups in the molecule, is obtained by reacting the component (o) and the component (a) in an organic solvent so that the ratio of the number of hydroxyl groups to the number of isocyanate groups becomes 1.01 or more, preferably 1.1 or more and 2.4 or less, more preferably 1.1 or more and 2.1 or less.

In the case where two or more organic diols are used, the reaction with the diisocyanate compound may be performed after mixing the two or more organic diols, or each organic diol may be reacted with the diisocyanate compound separately. After the organic diol and the diisocyanate compound are reacted, the resulting terminal isocyanate compound may be further reacted with another organic diol compound, and further reacted with the diisocyanate compound. The same applies to the case of using two or more diisocyanate compounds. Thus, the desired terminal isocyanate compound can be produced.

The reaction temperature of the component (o) and the component (a) is preferably 0 to 160 ℃, more preferably 10 to 150 ℃. The reaction time may be appropriately selected depending on the scale of the reaction and the reaction conditions employed. If necessary, the reaction may be carried out in the presence of a catalyst such as a metal or semi-metal compound of tertiary amine, alkali metal, alkaline earth metal, tin, zinc, titanium, cobalt or the like. The concentration of the total amount of the component (o) and the component (a) in the reaction solution is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction may be carried out at a high concentration at the beginning of the reaction, and then an organic solvent may be added.

Method for synthesizing terminal amine urea oligomer

The synthesis method of the terminal amine urea oligomer obtained by reacting the component (b) containing a compound having two primary or secondary amino groups in the molecule with the terminal isocyanate compound obtained by the above method is obtained by reacting in an organic solvent. The reaction temperature is preferably set to 0 to 160 ℃, more preferably 10 to 150 ℃. The reaction time may be appropriately selected depending on the scale of the reaction and the reaction conditions employed. The reaction concentration in the reaction solution is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction may be carried out at a high concentration at the beginning of the reaction, and then an organic solvent may be added.

Synthesis method for obtaining polyimide precursor (a) from terminal amine urea oligomer

The polyimide precursor (a) can be obtained by reacting a component (b) containing a tetracarboxylic dianhydride or a derivative thereof, and if necessary, a compound containing two primary or secondary amino groups in the molecule, with a terminal amine urea oligomer obtainable by the above-described method. The reaction is preferably carried out in an organic solvent, and the reaction temperature is preferably set to 20 to 100 ℃, more preferably 20 to 80 ℃. The reaction time may be appropriately selected depending on the scale of the reaction and the reaction conditions employed. The reaction concentration in the reaction solution is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction may be carried out at a high concentration at the beginning of the reaction, and then an organic solvent may be added.

The ratio of the component (o), the component (a), the component (b) and the component (c) to be reacted is preferably, for example, in terms of a molar ratio, the total amount of the component (a) and the component (c) to the total amount of the component (o) and the component (b) =0.8:1 to 1.2:1. (a) The proportion of the component (a) to the total amount of the component (c) is preferably 2 to 98 mol%, more preferably 10 to 96 mol%. The proportion of the component (o) in the total amount of the component (o) and the component (b) is preferably 1 to 49 mol%, more preferably 2 to 45 mol%.

Examples of the polyimide precursor as the polymer (B) include: polyamic acid, polyamic acid ester, and the like. The polyimide precursor as the polymer (B) can be synthesized by a known method as described in, for example, international publication No. WO 2013/157586.

[ terminal modifier ]

In the synthesis of the polymers (a) and (B) in the present invention, the above-described component (o), component (a), component (B), component (c) and, if necessary, an appropriate terminal modifier may be used together to synthesize a terminal-modified polymer.

Examples of the terminal modifier include: acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, compounds represented by the following formulas (m-1) to (m-6), 3- (3-trimethoxysilyl) propyl) -3, 4-dihydrofuran-2, 5-dione, 4,5,6, 7-tetrafluoroisobenzofuran-1, 3-dione, 4-ethynylphthalic anhydride, and other acid monoanhydrides;

dicarbonate diester compounds such as di-t-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride and nicotinyl chloride; monoamine compounds such as aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; and monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate and naphthyl isocyanate.

The ratio of the terminal modifier to be used is preferably 20 parts by mole or less, more preferably 10 parts by mole or less, based on 100 parts by mole of the total of the diamine component and the organic diol component to be used, if necessary.

Further, the polyimide may be obtained by ring-closing (imidizing) a polyimide precursor (a) of the polymer (a) or a polyimide precursor (hereinafter, also referred to simply as "polyimide precursor") of the polymer (B). The imidization ratio in the present specification means a ratio of an imide group to a total amount of an imide group derived from a tetracarboxylic dianhydride or a derivative thereof and a carboxyl group (or a derivative thereof). The imidization ratio is not necessarily 100%, and may be arbitrarily adjusted according to the purpose or use.

Examples of the method for imidizing the polyimide precursor include thermal imidization in which a solution of the polyimide precursor is directly heated, and catalytic imidization in which a catalyst is added to a solution of the polyimide precursor.

When the polyimide precursor is thermally imidized in a solution, the temperature is preferably 100 to 400 ℃, more preferably 120 to 250 ℃, and it is preferable to conduct the imidization reaction while removing water generated by the imidization reaction.

Catalytic imidization of the polyimide precursor can be performed by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor, preferably with stirring at-20 to 250 ℃, more preferably at 0 to 180 ℃. The amount of the basic catalyst is preferably 0.5 to 30 mol times, more preferably 2 to 20 mol times, the amount of the acid anhydride is preferably 1 to 50 mol times, more preferably 3 to 30 mol times, the amount of the acid amide group. The basic catalyst may be: pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like are preferable, among them, pyridine has a moderate basicity for allowing the reaction to proceed. The acid anhydride includes: among them, acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like are preferable because purification after completion of the reaction becomes easy if acetic anhydride is used. The imidization rate based on the catalytic imidization can be controlled by adjusting the catalyst amount, the reaction temperature, and the reaction time.

In the case of recovering the polyimide precursor or polyimide produced from the reaction solution of the polyimide precursor or polyimide, the reaction solution may be put into a solvent and precipitated. Examples of the solvent used for precipitation include methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, water, and the like. The polymer which is put into the solvent and precipitated is filtered and recovered, and then dried under normal pressure or reduced pressure, at normal temperature or by heating. In addition, when the polymer after the precipitation recovery is repeatedly subjected to, for example, 2 to 10 times of redissolution with an organic solvent and reprecipitation recovery, impurities in the polymer can be reduced. Examples of the solvent include alcohols, ketones, and hydrocarbons, and if three or more solvents selected from these are used, the purification efficiency is further improved, which is preferable.

The molecular weights of the polymers (a) and (B) used in the present invention are preferably 5000 to 1000000, more preferably 10000 to 150000 in terms of weight average molecular weight as measured by GPC (Gel Permeation Chromatography: gel permeation chromatography) in consideration of the strength of the liquid crystal alignment film thus obtained, workability at the time of film formation, and film coating property.

The blending ratio of the polymer component used in the method for producing a liquid crystal alignment film of the present invention is not particularly limited, and for example, the total amount of the polymer component contained in the liquid crystal alignment agent is preferably 0.1 to 30% by mass, more preferably 3 to 10% by mass.

The content of the polymer (a) in the liquid crystal aligning agent may be appropriately changed depending on the method of applying the liquid crystal aligning agent and the film thickness of the target liquid crystal alignment film, and is preferably 0.1 to 30% by mass, and particularly preferably 0.5 to 9.5% by mass.

In addition, in the liquid crystal aligning agent for producing a liquid crystal alignment film, a polymer (a) and a polymer (B) may be mixed, and other polymers than these may be mixed. In this case, the content of the other polymer is 0.5 to 15% by mass, preferably 1 to 10% by mass, based on the total amount of the polymer components. As other polymers other than them, there may be mentioned: acrylic polymers, methacrylic polymers, polystyrene, polyamides, polysiloxanes, or the like.

The solvent contained in the liquid crystal aligning agent is not particularly limited as long as it can dissolve the polymer (a), and examples thereof include: lactone solvents such as gamma valerolactone and gamma butyrolactone; lactam solvents such as γ -butyrolactam, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N- (N-propyl) -2-pyrrolidone, N-isopropyl-2-pyrrolidone, N- (N-butyl) -2-pyrrolidone, N- (t-butyl) -2-pyrrolidone, N- (N-pentyl) -2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, and the like; amide solvents such as N, N-dimethylformamide, N-dimethylacetamide, N-dimethylformamide, 3-methoxy-N, N-dimethylpropionamide, and 3-butoxy-N, N-dimethylpropionamide; 4-hydroxy-4-methyl-2-pentanone, 2, 6-dimethyl-4-heptanone (diisobutyl ketone), methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isopentyl lactate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, isopentyl propionate, isopentyl butyrate, diisopropyl ether, diisoamyl ether; carbonate solvents such as ethylene carbonate and propylene carbonate, and 1-hexanol, cyclohexanol, 1, 2-ethylene glycol, 2, 6-dimethyl-4-heptanol (diisobutylmethanol), 1, 3-dimethyl-2-imidazolidinone, and the like. They may be used singly or in combination of two or more.

The preferable combination of solvents includes: n-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and gamma-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and gamma-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone and N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and 2, 6-dimethyl-4-heptanone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, gamma-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and 2, 6-dimethyl-4-heptanone, gamma-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, N-methyl-2-pyrrolidone and gamma-butyrolactone and propylene glycol monobutyl ether and 2, 6-dimethyl-4-heptanone, N-methyl-2-pyrrolidone and gamma-butyrolactone and propylene glycol monobutyl ether and diisopropyl ether, N-methyl-2-pyrrolidone and gamma-butyrolactone and propylene glycol monobutyl ether and 2, 6-dimethyl-4-heptanol, N-methyl-2-pyrrolidone and gamma-butyrolactone and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone and propylene glycol monobutyl ether and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and ethylene glycol monobutyl ether, and the like. The kind and content of such a solvent are appropriately selected according to the application apparatus, application conditions, application environment, and the like of the liquid crystal aligning agent.

< liquid Crystal alignment agent >)

The liquid crystal aligning agent of the present invention may contain other components than those described above, for example, a crosslinkable compound, a functional silane compound, a surfactant, a compound having a photopolymerizable group, and the like, as required.

The crosslinkable compound can be used for the purpose of improving the strength of the liquid crystal alignment film. Examples of the crosslinkable compound include: the compounds having an isocyanate group or a cyclic carbonate group, or a compound having at least one group selected from the group consisting of lower alkoxyalkyl groups, and a compound having a blocked isocyanate group described in paragraphs [0109] to [0113] of International publication WO2016/047771, and the like.

The compound having a blocked isocyanate group can be obtained as a commercially available product, and for example, it is preferable to use: CORONATE APstable M, CORONATE 2503, 2515, 2507, 2513, 2555, MILLIONATE MS-50 (manufactured by TOSOH Co., ltd.), TAKENATE B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (manufactured by Mitsui chemical Co., ltd.) and the like.

Specific examples of the preferable crosslinkable compound include compounds represented by the following formulas (CL-1) to (CL-11).

The above is an example of the crosslinkable compound, but is not limited thereto. The crosslinkable compound used in the liquid crystal aligning agent of the present invention may be one kind or two or more kinds may be combined.

The content of the other crosslinkable compound in the liquid crystal aligning agent of the present invention is 0.1 to 150 parts by mass, or 0.1 to 100 parts by mass, or 1 to 50 parts by mass, based on 100 parts by mass of all the polymer components.

The functional silane compound may be used for the purpose of improving the adhesion between the liquid crystal alignment film and the base substrate. Specific examples thereof include silane compounds described in paragraph [0019] of International publication No. 2014/119682. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, relative to 100 parts by mass of all the polymer components.

The surfactant may be used for the purpose of improving uniformity of film thickness and surface smoothness of the liquid crystal alignment film. The above-mentioned compounds include: fluorine-based surfactants, silicone-based surfactants, nonionic-based surfactants, and the like. Specific examples thereof include the surfactants described in paragraph [0117] of International publication WO 2016/047771. The amount of the surfactant used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, based on 100 parts by mass of all the polymer components contained in the liquid crystal aligning agent.

Examples of the compound having a photopolymerizable group include compounds having one or more polymerizable unsaturated groups such as an acrylate group and a methacrylate group in the molecule.

Further, as a compound for promoting charge transfer in the liquid crystal alignment film to promote charge release in the element, a nitrogen atom-containing heterocyclic amine compound represented by the formulas [ M1] to [ M156] described in paragraphs [0194] to [0200] of international publication No. WO2011/132751 (2011.10.27), more preferably 3-aminomethylpyridine or 4-aminomethylpyridine, may be added to the liquid crystal alignment agent of the present invention. The amine compound may be added directly to the liquid crystal aligning agent, or may be added after preparing a solution having a concentration of, for example, 0.1 to 10 mass%, preferably 1 to 7 mass%. The solvent is not particularly limited as long as it dissolves the polymer component.

In the liquid crystal aligning agent of the present invention, an imidization accelerator or the like may be added for the purpose of efficiently imidizing by heating when the coating film is baked.

The solid content concentration (the ratio 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) in the liquid crystal aligning agent can be appropriately selected in consideration of viscosity, volatility, and the like, and is preferably in the range of 0.5 to 15 mass%, more preferably 1 to 10 mass%.

The particularly preferable range of the solid content concentration varies depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, in the case of spin coating, the solid content concentration is particularly preferably in the range of 1.5 to 4.5 mass%. When the printing method is used, it is particularly preferable to set the solid content concentration to a range of 3 to 9 mass%, and thereby set the solution viscosity to a range of 12 to 50mpa·s. In the case of using the inkjet method, it is particularly preferable to set the solid content concentration to a range of 1 to 5 mass%, and thereby set the solution viscosity to a range of 3 to 15mpa·s.

Liquid crystal alignment film/liquid crystal display element

The liquid crystal alignment film can be produced by using the above liquid crystal alignment agent. The liquid crystal display device of the present invention further includes a liquid crystal alignment film formed using the liquid crystal alignment agent. The operation mode of the liquid crystal display device of the present invention is not particularly limited, and the liquid crystal display device can be applied to various operation modes such as a TN (Twisted Nematic) mode, a STN (Super Twisted Nematic) mode, a vertical alignment mode (including a VA (Vertical Alignment: vertical alignment) -MVA (Multi-domain Vertical Alignment: multi-quadrant vertical alignment) mode, a VA-PVA (Patterned Vertical Alignment: pattern vertical alignment) mode, an In-Plane Switching mode (IPS mode: in-Plane Switching mode), an FFS (Fringe Field Switching: fringe field Switching) mode, and an optically compensated bend mode (OCB mode: optically Compensated Bend mode).

The liquid crystal display element of the present invention can be manufactured, for example, by the following steps (1) to (4), the method including steps (1) to (2) and (4), the method including steps (1) to (3), (4-2) and (4-4), or the method including steps (1) to (3), (4-3) and (4-4).

< procedure (1): process of applying liquid Crystal alignment agent to substrate

The liquid crystal aligning agent of the present invention is applied to one surface of a substrate provided with a patterned transparent conductive film by a suitable application method such as roll coater method, spin coating method, printing method, ink jet method, or the like. The substrate is not particularly limited as long as it is a substrate having high transparency, and a plastic substrate such as an acrylic substrate or a polycarbonate substrate may be used together with a glass substrate or a silicon nitride substrate. In the reflective liquid crystal display element, if the substrate is a single-sided substrate, an opaque material such as a silicon wafer may be used, and in this case, a material reflecting light such as aluminum may be used as the electrode. In the case of manufacturing an IPS type or FFS type liquid crystal device, a substrate provided with an electrode formed of a transparent conductive film or a metal film patterned into a comb-teeth type and a counter substrate provided with no electrode are used.

Examples of the method of applying the liquid crystal aligning agent to the substrate and forming a film include: screen printing, offset printing, flexography, inkjet, or spray coating. Among them, a method of coating and film formation by an inkjet method can be preferably used.

< procedure (2): firing the applied liquid crystal aligning agent

The step (2) is a step of firing the liquid crystal aligning agent applied to the substrate to form a film. After the liquid crystal alignment agent is coated on the substrate, the solvent may be evaporated or the polyamic acid or polyamic acid ester may be thermally imidized by using a heating unit such as a heating plate, a thermal circulation oven, or an IR (infrared) oven. The drying and firing steps after the application of the liquid crystal aligning agent of the present invention may be performed at any temperature and for any time or may be performed a plurality of times. The temperature of the solvent for reducing the liquid crystal aligning agent may be, for example, 40 to 180 ℃. From the viewpoint of shortening the process, it may be carried out at 40 to 150 ℃. The firing time is not particularly limited, and may be 1 to 10 minutes or 1 to 5 minutes. In the case of thermal imidization of the polyamic acid or polyamic acid ester, a step of baking at a temperature ranging from 150 to 300 ℃ or from 150 to 250 ℃ may be added after the above step. The firing time is not particularly limited, and examples thereof include a firing time of 5 to 40 minutes or 5 to 30 minutes.

If the film after firing is too thin, the reliability of the liquid crystal display element may be lowered, and therefore, it is preferably 5 to 300nm, more preferably 10 to 200nm.

< procedure (3): a step of orienting the film obtained in the step (2)

The step (3) is a step of optionally subjecting the film obtained in the step (2) to an orientation treatment. That is, in a liquid crystal display element of a horizontal alignment type such as an IPS type or FFS type, the coating film is subjected to an alignment ability imparting treatment. On the other hand, in a vertical alignment type liquid crystal display element such as VA mode or PSA mode, the formed coating film may be used as a liquid crystal alignment film as it is, but the coating film may be subjected to an alignment ability imparting treatment. Examples of the alignment treatment method of the liquid crystal alignment film include a rubbing treatment method and a photo-alignment treatment method. As the photo-alignment treatment method, the following methods are exemplified: the surface of the film is irradiated with radiation biased in a fixed direction, and if necessary, is preferably subjected to a heat treatment at a temperature of 150 to 250 ℃ to impart liquid crystal alignment (also referred to as liquid crystal alignment ability). As the radiation, ultraviolet or visible light having a wavelength of 100 to 800nm can be used. Among them, ultraviolet rays having a wavelength of 100 to 400nm are preferable, and ultraviolet rays having a wavelength of 200 to 400nm are more preferable.

The radiation is preferably applied in an amount of 1 to 10000mJ/cm ² . Of these, 100 to 5000mJ/cm is preferable ² . In the case of irradiation with radiation, the substrate having the film may be irradiated with radiation while being heated at 50 to 250 ℃ in order to improve the alignment of the liquid crystal. The liquid crystal alignment film produced as described above can stably align liquid crystal molecules in a fixed direction.

In the above method, the liquid crystal alignment film irradiated with the polarized radiation may be subjected to a contact treatment with water or a solvent, or the liquid crystal alignment film irradiated with the radiation may be subjected to a heat treatment.

The solvent used in the contact treatment is not particularly limited as long as it is a solvent that dissolves a decomposition product formed from the film-like material upon irradiation with radiation. As specific examples, there may be mentioned: water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, and the like. Among them, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate is preferable, and water, 1-methoxy-2-propanol or ethyl lactate is more preferable from the viewpoints of versatility and safety of solvents. The solvent may be one kind, or two or more kinds may be combined.

The temperature at which the above-mentioned coating film irradiated with radiation is heat-treated is more preferably 50 to 300 ℃, still more preferably 120 to 250 ℃. The time for the heat treatment is preferably 1 to 30 minutes.

< procedure (4): process for manufacturing liquid Crystal cell

Two substrates on which the liquid crystal alignment film was formed as described above were prepared, and liquid crystal was disposed between the two substrates disposed opposite to each other. Specifically, the following two methods are exemplified. In the first method, first, two substrates are arranged to face each other with a gap (cell gap) therebetween so that the liquid crystal alignment films face each other. Next, the peripheral portions of the two substrates are bonded together with a sealant, and a liquid crystal composition is injected into a cell gap defined by the substrate surface and the sealant to contact the film surface, and then the injection hole is sealed.

The second method is a method called an ODF (One Drop Fill) method. A liquid crystal composition is further dropped at predetermined places on the liquid crystal alignment film surface by applying a uv-curable sealant to predetermined places on one of the two substrates on which the liquid crystal alignment film is formed, for example. Then, the liquid crystal composition is bonded to the other substrate so as to face the liquid crystal alignment film, and pushed to the entire surface of the substrate to be in contact with the film surface. Then, ultraviolet light is irradiated to the entire surface of the substrate, and the sealant is cured. In either method, it is desirable to further heat the liquid crystal composition to be used to a temperature at which the liquid crystal composition is in phase in each direction, and then slowly cool the liquid crystal composition to room temperature, thereby removing the flow orientation during filling of the liquid crystal.

When the coating film is subjected to the rubbing treatment, the two substrates are disposed so that the rubbing directions of the coating films are at a predetermined angle, for example, orthogonal or antiparallel to each other.

As the sealant, for example, an epoxy resin containing a curing agent and alumina balls as spacers, or the like can be used. The liquid crystal includes nematic liquid crystal and smectic liquid crystal, and among them, nematic liquid crystal is preferable.

The liquid crystal aligning agent of the present invention is also preferably used for the following liquid crystal display element (PSA-type liquid crystal display element): a liquid crystal layer is provided between a pair of substrates provided with electrodes, a liquid crystal composition containing a polymerizable compound that is polymerized by at least one of active energy rays and heat is disposed between the pair of substrates, and a voltage is applied across the electrodes and at least one of active energy rays and heat is applied thereto, whereby the liquid crystal composition is produced through a step of polymerizing the polymerizable compound.

Furthermore, the liquid of the present inventionThe crystal aligning agent is also preferably used for the following liquid crystal display element (SC-PVA mode)

Liquid crystal display element): a liquid crystal layer is provided between a pair of substrates provided with electrodes, a liquid crystal alignment film containing a polymerizable group that is polymerized by at least one of active energy rays and heat is disposed between the pair of substrates, and the liquid crystal alignment film is manufactured by applying a voltage between the electrodes.

(4-2) case of PSA-type liquid Crystal display element

The procedure was the same as in (4) above, except that the liquid crystal composition containing the polymerizable compound was injected or dropped.

(4-3) case of SC-PVA mode liquid Crystal display element

After the same steps as those of (4), a method of manufacturing a liquid crystal display element by a step of irradiating ultraviolet rays described later may be used. According to this method, as in the case of manufacturing the PSA-type liquid crystal display element, a liquid crystal display element excellent in response speed can be obtained with a small amount of light irradiation. The compound having a polymerizable group may be a compound having one or more polymerizable unsaturated groups such as an acrylate group and a methacrylate group in the molecule, and the content thereof is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, relative to 100 parts by mass of all the polymer components. The polymerizable group may be a polymer used for a liquid crystal aligning agent, and examples of such a polymer include a polymer obtained by using a diamine component including a diamine having the photopolymerizable group at a terminal thereof for a reaction.

Step (4-4): a step of irradiating ultraviolet rays

The liquid crystal cell is irradiated with light in a state where a voltage is applied between the conductive films of the pair of substrates obtained in the above (4-2) or (4-3). The voltage applied here may be, for example, 5 to 50V direct current or alternating current. The irradiation light may be, for example, ultraviolet rays or visible rays including light having a wavelength of 150 to 800nm, and is preferablyUltraviolet rays including light having a wavelength of 300 to 400 nm. As a light source for irradiating light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used. The irradiation amount of light is preferably 1000 to 200000J/m ² More preferably 1000 to 100000J/m ² 。

Further, a polarizing plate may be attached to the outer surface of the liquid crystal cell as needed to obtain a liquid crystal display element. As the polarizing plate attached to the outer surface of the liquid crystal cell, there may be mentioned: a polarizing plate formed by sandwiching a polarizing film called "H film" with a cellulose acetate protective film; or a polarizing plate composed of an H film itself, wherein the H film is formed by absorbing iodine while stretching and orienting polyvinyl alcohol.

The liquid crystal display element of the present invention can be effectively used for various devices, for example, various display devices such as a clock, a portable game machine, a word processor, a notebook computer, a car navigation system, a video camera (cam recorder), a PDAA (Personal Digital Assistant: palm computer), a digital camera, a mobile phone, a smart phone, various monitors, a liquid crystal television, and an information display. The polymer composition contained in the liquid crystal aligning agent can be used for a liquid crystal alignment film for a phase difference film, a scanning antenna, a liquid crystal alignment film for a liquid crystal array antenna, a liquid crystal alignment film for a liquid crystal light adjusting element for a transmission scattering type, or other applications, for example, a protective film for a color filter, a gate insulating film for a flexible display, and a substrate material.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The abbreviations of the compounds and solvents are as follows.

(organic solvent)

NMP: n-methyl-2-pyrrolidone.

GBL: gamma-butyrolactone.

BCS: ethylene glycol monobutyl ether.

(diamine)

DA-1 to DA-8: compounds represented by the following structural formulae (DA-1) to (DA-8), respectively.

(acid dianhydride)

CA-1 to CA-5: compounds represented by the following structural formulae (CA-1) to (CA-5), respectively.

(diisocyanate)

DI-1:4,4' -diphenylmethane diisocyanate.

(diol)

EG-1: tetraethylene glycol.

EG-2: polyethylene Glycol 400 (manufactured by tokyo chemical industry Co., ltd.).

EG-3: polyethylene Glycol 600 (manufactured by tokyo chemical industry Co., ltd.).

< viscosity >

In the synthesis example, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Tokyo industries Co., ltd.) in a sample size of 1.1mL, a conical rotor TE-1 (1 DEG 34', R24) and a temperature of 25 ℃.

< determination of imidization Rate of polyimide >)

The imidization ratio of the polyimide in the synthesis example was measured as follows. Polyimide powder (30 mg) was added to an NMR (nuclear magnetic resonance) sample tube (NMR standard sample tube, φ 5 (manufactured by Bruhnia sciences Co.), deuterated dimethyl sulfoxide (DMSO-d 6,0.05 mass% TMS (tetramethylsilane)) mixture (0.53 mL) was added, and ultrasonic waves were applied to dissolve the mixture completely. The solution was subjected to proton NMR of 500MHz by an NMR analyzer (JNW-ECA 500) (manufactured by Japanese electronic data UM Co.). The imidization rate was determined by using the peak integrated value of protons derived from the structure unchanged before and after imidization as a reference proton and the peak integrated value of protons derived from NH groups of amic acid, which appeared in the vicinity of 9.5 to 10.0ppm, as a reference proton.

Imidization ratio (%) = (1- α·x/y) ×100

In the above formula, x is a proton peak integral value of NH group derived from amic acid, y is a peak integral value of reference proton, and α is a number ratio of reference proton to one NH group proton of amic acid in the case of polyamic acid (imidization ratio is 0%).

[ Synthesis of Polymer ]

Synthesis example 1

EG-1 (0.32 g,1.65 mmol) was weighed into a 50mL eggplant-shaped flask equipped with a stirrer and a nitrogen inlet tube, and NMP (1.3 g) was added thereto and dissolved by stirring while nitrogen was being fed. While stirring the solution under water cooling, DI-1 (0.83 g,3.30 mmol) and NMP (3.30 g) were added and stirred under nitrogen at 70℃for 3 hours. Then, NMP (22.0 g) was added for dilution and further stirred for 30 minutes. Then, a solution of DA-6 (1.85 g,9.35 mmol) in NMP (5.00 g) was added, NMP (2.50 g) was further added, and the mixture was stirred under nitrogen at 23℃for 2 hours. CA-2 (1.49 g,7.59 mmol) and NMP (6.30 g) were then added, and stirred under a nitrogen atmosphere at 23℃for 2 hours, thereby obtaining a solution (viscosity: 32 mPas) of the polymer (polymer-1).

Synthesis examples 2 to 5

The same procedure as in Synthesis example 1 was followed using diamine, acid dianhydride, diisocyanate and diol shown in Table 1 below, to obtain solutions of polyurethane amic acids (polymer-2) to (polymer-5) shown in Table 1 below. In table 1, the numerical values described below the compound names indicate the mass of each compound used for synthesis, and the numerical values in brackets indicate the amount (parts by mole) of each compound used per 100 parts by mole of the total amount of the diamine component and the diol component.

TABLE 1

Synthesis example 6

EG-2 (0.34 g,0.84 mmol) and NMP (1.9 g) were weighed into a 100mL eggplant-shaped flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring while nitrogen was fed. While stirring the solution under water cooling, DI-1 (0.42 g,1.68 mmol) and NMP (2.24 g) were added and stirred under nitrogen at 70℃for 3 hours. Then, NMP (20.0 g) and GBL (20.0 g) were added for dilution, and further stirred for 30 minutes. A solution of DA-5 (5.77 g,20.2 mmol) in NMP (10.9 g) and GBL (15.1 g) was then added and stirred under nitrogen at 23℃for 2 hours. CA-2 (3.67 g (18.7 mmol), NMP (2.25 g) and GBL (2.25 g) were then added and stirred under a nitrogen atmosphere at 23℃for 2 hours, and after the completion of the reaction, NMP (8.50 g) and GBL (8.50 g) were added to adjust the concentration of the solution and stirred for 1 hour, thereby obtaining a solution (viscosity: 112 mPas) of the polymer (polymer-6).

Synthesis examples 7 to 14

The same procedure as in Synthesis example 6 was followed using diamine, acid dianhydride, diisocyanate and diol shown in Table 2 below, to obtain solutions of polymers (polymers-7) to (polymer-14) shown in Table 2 below. In table 2, the numerical values described below the compound names indicate the mass of each compound used for synthesis, and the numerical values in brackets indicate the amount (parts by mole) of each compound used per 100 parts by mole of the total amount of the diamine component and the diol component.

TABLE 2

Synthesis example 15

DA-5 (3.16 g,11.0 mmol) and NMP (28.5 g) were weighed into a 100mL eggplant-shaped flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring while nitrogen was fed. While stirring the solution under water cooling, CA-2 (1.67 g,8.52 mmol) and NMP (6.98 g) were added and stirred under nitrogen at 23℃for 2 hours. EG-3 (0.58 g,0.96 mmol) and NMP (4.22 g) were then added to the stirred solution. DI-1 (0.48 g,1.92 mmol) and NMP (3.52 g) were then added and stirred under a nitrogen atmosphere at 50℃for 3 hours, thereby obtaining a solution (viscosity: 178 mPas) of the polymer (polymer-15).

Synthesis example 16

DA-5 (7.45 g,26.0 mmol), NMP (33.5 g) and GBL (33.5 g) were weighed into a 100mL eggplant-shaped flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring while nitrogen was being fed. While stirring the diamine solution under water cooling, CA-2 (4.74 g,24.2 mmol), NMP (11.2 g) and GBL (11.2 g) were added, and the mixture was stirred under a nitrogen atmosphere for 2 hours, thereby obtaining a solution (viscosity: 182 mPa.s) of polyamic acid (PAA-1).

Synthesis example 17

DA-5 (7.45 g,26.0 mmol), NMP (33.5 g) and GBL (33.5 g) were weighed into a 100mL eggplant-shaped flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring while nitrogen was being fed. While stirring the diamine solution under water cooling, CA-3 (5.42 g,24.2 mmol), NMP (13.8 g) and GBL (13.8 g) were added, and the mixture was stirred under a nitrogen atmosphere for 2 hours, thereby obtaining a solution (viscosity: 167 mPa.s) of polyamic acid (PAA-2).

Synthesis example 18

DA-4 (11.7 g,40.2 mmol), DA-2 (8.73 g,21.9 mmol), DA-3 (6.10 g,11.0 mmol), and NMP (113.2 g) were weighed into a 200mL eggplant-shaped flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring while nitrogen was being fed. CA-1 (9.40 g,47.5 mmol) and NMP (32.4 g) were added while stirring the diamine solution under water cooling, and stirred under nitrogen at 50℃for 2 hours. Further, CA-2 (4.61 g,23.5 mmol) and NMP (16.6 g) were added, and stirred under a nitrogen atmosphere at 23℃for 2 hours, thereby obtaining a solution (viscosity: 1230 mPa.s) of polyamic acid (PAA-3).

A200 mL Erlenmeyer flask equipped with a stirrer was charged with a solution (100 g) of the polyamic acid (PAA-3) obtained above, and di-t-butyl dicarbonate (hereinafter, also referred to as Boc) was added as a terminal modifier ₂ O) (1.32 g,6.05 mmol) was stirred at 40℃for 15 hours to give a solution of the terminal-modified polyamic acid (PAA-3-1).

A200 mL Erlenmeyer flask equipped with a stirrer was charged with NMP (66.7 g), acetic anhydride (12.9 g) and pyridine (4.27 g) by separating the above solution (100 g) (PAA-3-1), and the mixture was stirred at room temperature for 30 minutes and then reacted at 60℃for 4 hours. The reaction solution was poured into methanol (640 g), and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 80℃to obtain a polyimide powder (imidization ratio: 91%).

Further, a 100mL Erlenmeyer flask equipped with a stirrer was charged with NMP (70.4 g) and stirred at 70℃for 24 hours to dissolve the polyimide powder (9.60 g), thereby obtaining a polyimide (SPI-1) solution.

Synthesis example 19

DA-1 (8.04 g,40.2 mmol), DA-2 (4.36 g,10.9 mmol), DA-3 (12.2 g,21.9 mmol) and NMP (98.4 g) were weighed into a 200mL eggplant-shaped flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring while nitrogen was being fed. CA-1 (9.40 g,47.5 mmol) and NMP (37.6 g) were added while stirring the diamine solution under water cooling, and stirred under nitrogen at 50℃for 2 hours. Further, CA-2 (4.65 g,23.7 mmol) and NMP (18.6 g) were added, and stirred under a nitrogen atmosphere at 23℃for 2 hours to give a solution (viscosity: 1230 mPa.s) of polyamic acid (PAA-4).

A200 mL Erlenmeyer flask equipped with a stirrer was charged with Boc (100 g) of the solution of polyamic acid (PAA-4) obtained above ₂ O (1.24 g,5.68 mmol) was stirred at 40℃for 15 hours, thereby obtaining a solution of the terminal-modified polyamic acid (PAA-4-1).

A200 mL Erlenmeyer flask equipped with a stirrer was charged with NMP (66.7 g), acetic anhydride (14.2 g) and pyridine (4.70 g) by separating the solution (100 g) of (PAA-4-1), and the mixture was stirred at room temperature for 30 minutes and then reacted at 60℃for 4 hours. The reaction solution was poured into methanol (650 g), and the resulting precipitate was filtered off. After the precipitate was washed with methanol, it was dried under reduced pressure at 80℃to obtain a polyimide powder (imidization ratio: 90%).

Further, a 100mL Erlenmeyer flask equipped with a stirrer was charged with NMP (70.4 g) and stirred at 70℃for 24 hours to dissolve the polyimide powder (9.60 g), thereby obtaining a polyimide (SPI-2) solution.

Synthesis example 20

DA-7 (4.03 g,16.5 mmol), DA-8 (3.29 g,16.5 mmol), and NMP (65.9 g) were weighed into a 100mL eggplant-shaped flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring while nitrogen was being fed. While stirring the diamine solution under water cooling, CA-4 (6.19 g,24.8 mmol) was added, NMP (10.7 g) was further added, and the mixture was stirred under nitrogen at 50℃for 3 hours. Further, CA-5 (2.04 g,6.93 mmol) was added, NMP (11.6 g) was further added, and the mixture was stirred under a nitrogen atmosphere at 70℃for 6 hours to give a solution (viscosity: 495 mPa.s) of the polymer (PAA-5).

[ preparation of liquid Crystal alignment agent ]

Example 1

A50 mL Erlenmeyer flask equipped with a stirrer was charged with a solution (6.60 g) of the polymer (polymer-1) obtained in Synthesis example 1, NMP (0.06 g), GBL (9.34 g) and BCS (4.00 g) were added, and the mixture was stirred at room temperature for 2 hours, thereby obtaining a liquid crystal aligning agent (1).

Examples 2 to 16 and comparative examples 1 to 4

Liquid crystal aligning agents (2) to (20) were obtained in the same manner as in example 1, except that the types and amounts of the polymer solution and the solvent used were changed as shown in table 3.

TABLE 3

Hereinafter, a method for manufacturing a liquid crystal display element for evaluating a voltage holding ratio is described.

[ production of liquid Crystal display element ]

First, a substrate with electrodes is prepared. The substrate was a glass substrate having a size of 30mm×40mm and a thickness of 1.1 mm. An ITO electrode having a film thickness of 35nm was formed on the substrate, and the electrode had a stripe pattern having a length of 40mm and a width of 10 mm.

Then, the obtained liquid crystal aligning agent was filtered by a filter having a pore diameter of 1.0 μm, and then applied to the prepared electrode-equipped substrate by spin coating. After drying on a heating plate at 80℃for 2 minutes, baking was performed for 20 minutes in an IR oven at 230℃to form a coating film having a film thickness of 100nm, thereby obtaining a substrate with a liquid crystal alignment film. The liquid crystal alignment film was rubbed with a rayon cloth (roller diameter: 120mm, roller rotation speed: 1000rpm, moving speed: 20mm/sec, pressing length: 0.4 mm), then washed by ultrasonic irradiation in pure water for 1 minute, and after removing water droplets by blowing, it was dried at 80℃for 10 minutes to obtain a substrate with a liquid crystal alignment film. Two substrates with liquid crystal alignment films were prepared, spacers (Silk ball, SW-D1, manufactured by soyawing catalyst chemical company) having a diameter of 4 μm were spread on the surface of one of the substrates, a thermosetting sealant (XN-1500T, manufactured by samsung chemical company) was printed thereon, and the other substrate was bonded so that the rubbing direction was opposite and the film surfaces were opposed, and then the sealant was cured to prepare a blank. The negative type liquid crystal MLC-7026 (manufactured by MERCK Co.) was injected into the empty cell by vacuum injection, and the injection port was sealed to obtain a liquid crystal cell. The resulting liquid crystal cell was then heated at 120℃for 1 hour, and left at 23℃for one day for each evaluation.

< Voltage holding Rate >)

The voltage of 1V was applied to the liquid crystal display element at 60℃for 60 μsec, and the voltage after 16.67msec was measured, and the voltage was evaluated as the voltage holding ratio. The results are shown in Table 4. The higher the value of the voltage holding ratio, the better. It is known that when the voltage holding ratio, which is one of the electrical characteristics of the liquid crystal display element, increases, line burn-in, which is one of the display defects of the liquid crystal display element, is less likely to occur.

TABLE 4

< evaluation of whitening Properties >)

0.1mL of the liquid crystal aligning agents (1) to (20) were added dropwise to the chromium vapor deposition substrate, and the mixture was allowed to stand in an atmosphere of a temperature of 23℃and a humidity of 70%. After a predetermined time has elapsed after the dropping, the edges and the center portions of the drops were observed with an optical microscope to confirm whether or not whitening was occurring. The results are shown in Table 5. In the present evaluation, the phenomenon in which the dissolved polyimide precipitates or aggregates to cause cloudiness in the droplets is defined as a whitening phenomenon. The state in which the droplet was not whitened at all was evaluated as "good", the state in which only the edge of the droplet was whitened was evaluated as "Δ", and the state in which the entire surface of the droplet was whitened was evaluated as "x". The longer the time to get good is.

TABLE 5

In general, when a negative type liquid crystal is used as a liquid crystal material, the voltage holding ratio is lowered, and display failure (line burn-in) is likely to occur. However, by using the liquid crystal aligning agent of the embodiment of the present invention, even in the case where a negative type liquid crystal is used as a liquid crystal material, a liquid crystal display element having a high voltage holding ratio (i.e., a liquid crystal display element having a low occurrence of defective display (line burn-in)) is obtained.

Further, the liquid crystal aligning agent according to the examples of the present invention is less likely to cause a phenomenon of moisture absorption and whitening, and therefore, is less likely to cause foreign matters, clogging, and the like when a coating film is obtained, and the resulting film has less surface roughness, and can exhibit the original characteristics of a liquid crystal alignment film even when dried and heated.

The entire contents of the specification, claims, drawings and abstract of japanese patent application 2020-192467, filed on 11/19/2020, are incorporated herein by reference as if disclosed in the specification of the present invention.

Claims

1. A liquid crystal aligning agent characterized by comprising the following component A,

component A: at least one polymer A selected from the group consisting of a copolymer having a repeating unit represented by the following formula (a), a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), and a polyimide which is an imide of the copolymer,

At least one of the repeating unit represented by the following formula (a), the repeating unit represented by the following formula (1) and the repeating unit represented by the following formula (2) has a divalent organic group represented by the following formula (EG),

x represents a tetravalent organic group, Y represents a divalent organic group derived from a diamine, two R's each independently represent a hydrogen atom or a monovalent organic group, two Z's each independently represent a hydrogen atom or a monovalent organic group,

A ₁ is a divalent organic group, A _1’ Is a divalent organic group derived from diamine, C ₁ And C _1’ Each independently is a hydrogen atom or a monovalent organic group,

A ₂ is a divalent organic group, A _2’ To remove a divalent organic group containing hydrogen atoms in two hydroxyl groups from an organic diol,

r represents a hydrogen atom or a methyl group, and n is an integer of 3 to 40.

2. The liquid crystal aligning agent according to claim 1, wherein,

x in the formula (a) is a tetravalent organic group derived from tetracarboxylic dianhydride or a derivative thereofA group A in the formula (1) ₁ Is a divalent organic group derived from a diisocyanate, A in the formula (2) ₂ Is a divalent organic group derived from a diisocyanate.

3. The liquid crystal aligning agent according to claim 1 or 2, wherein,

in the formula (EG), n is an integer of 4 to 40.

4. A liquid crystal aligning agent according to any one of claim 1 to 3, wherein,

y in the formula (a) and A in the formula (1) _1’ Each independently is a divalent organic group derived from a diamine selected from the group consisting of a diamine represented by the following formula (O), a diamine having an amide bond or a urea bond, 3' -diaminodiphenylmethane, 3,4' -diaminodiphenylmethane, 4' -diaminobenzophenone, 1, 4-bis (4-aminophenyl) benzene, 1, 3-bis (4-aminophenyl) benzene, 1, 4-bis (4-aminobenzyl) benzene, and a diamine represented by the following formula (d) _o ) Diamines shown, 4- (2- (methylamino) ethyl) aniline, 4- (2-aminoethyl) aniline, diamines having the group "-N (D) -", formula (D) _EG ) In the group of diamines shown, D represents a protecting group which is detached and substituted by hydrogen atoms by heating,

ar represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring, two Ar's being optionally the same or different, any hydrogen atom in the benzene ring, biphenyl structure, or naphthalene ring being optionally substituted with a monovalent group, p is an integer of 0 or 1, Q ₂ Represents- (CH) ₂ ) _n -, or the- (CH) ₂ ) _n -CH of ₂ -a group wherein at least a part of the group is substituted with any one of-O-, -C (=o) -or-O-C (=o) -and n is an integer of 2 to 18, wherein, in Q ₂ Having ether linkagesIn the case of Q ₂ The total number of ether bonds is 3 or less,

a plurality of m are optionally each the same or different,

ar each independently represents a divalent aromatic group or condensed ring group, optionally the same or different, one or more hydrogen atoms on the aromatic group or condensed ring group being optionally substituted with a monovalent group, and n represents an integer of 3 to 40.

5. The liquid crystal aligning agent according to any one of claims 1 to 4, wherein,

a in the formula (1) ₁ And A in the formula (2) ₂ Each independently is: i a divalent organic group derived from an aromatic diisocyanate, wherein in the diisocyanate structure o=c=n-R-n=c=o, R is an organic group having 6 to 30 carbon atoms with at least one benzene ring; or ii a divalent organic group derived from an aliphatic diisocyanate, wherein in the diisocyanate structure o=c=n-R-n=c=o, R is an organic group having 4 to 30 carbon atoms and having no aliphatic group.

6. The liquid crystal aligning agent according to any one of claims 1 to 5, wherein,

a in the formula (1) ₁ And A in the formula (2) ₂ Each independently is a divalent organic group derived from a diisocyanate selected from the group consisting of,

7. The liquid crystal aligning agent according to any one of claims 1 to 6, wherein,

the organic diol in the formula (2) is a diol containing a divalent organic group represented by the formula (EG).

8. The liquid crystal aligning agent according to claim 7, wherein,

the diol containing the divalent organic group represented by the formula (EG) is a diol in which hydrogen atoms are bonded to both ends of the divalent organic group represented by the formula (EG).

9. The liquid crystal aligning agent according to any one of claims 1 to 8, wherein,

x in (a) is a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or a derivative thereof, a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride or a derivative thereof, or a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride or a derivative thereof.

10. The liquid crystal aligning agent according to any one of claims 1 to 9, wherein,

x in the formula (a) is a tetravalent organic group derived from tetracarboxylic dianhydride represented by the formula (t) or a derivative thereof,

wherein X is ₁ Is selected from the structures in the following formulas (X1-1) to (X1-25), which represent bonding bonds,

in the formulae (X1-1) to (X1-4), R ₁ ～R ₂₁ Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, represents a bond,

In the formulae (X1-24) to (X1-25), j and k are integers of 0 or 1, A ₁ And A ₂ Each independently represents a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or amide, a plurality of A ₂ Optionally each being the same or different.

11. The liquid crystal aligning agent according to any one of claims 1 to 10, wherein,

the content of the repeating unit represented by the formula (a) is 2 to 98 mol% based on the entire repeating unit constituting the polymer a, the content of the repeating unit represented by the formula (1) is 1 to 49 mol% based on the entire repeating unit constituting the polymer a, and the content of the repeating unit represented by the formula (2) is 1 to 49 mol% based on the entire repeating unit constituting the polymer a.

12. The liquid crystal aligning agent according to any one of claim 1 to 11, wherein,

the liquid crystal aligning agent further comprises a component B,

and the component B comprises the following components: a polymer B different from the polymer a, the polymer B being at least one polymer selected from the group consisting of polyimide precursors and imidized polymers thereof.

13. A method for producing a polymer A, comprising the steps of:

reacting an o component comprising an organic diol having two hydroxyl groups in a molecule with an a component comprising a compound having two isocyanate groups in a molecule to synthesize a terminal isocyanate compound, then reacting a b component comprising a compound having two primary or secondary amino groups in a molecule to synthesize a terminal amine urea oligomer, further reacting with a c component comprising a tetracarboxylic dianhydride or a derivative thereof, wherein at least one of the compounds constituting the o component, the a component, the b component and the c component has a partial structure represented by the following formula (EG) in a molecule,

R represents a hydrogen atom or a methyl group, and n is an integer of 3 to 40.

14. The method for producing a polymer according to claim 13, comprising the steps of:

make it contain "H-A _2’ The O component of the diol compound represented by-H "and the compound comprising o=c=n-A ₁ -reacting a component a of a diisocyanate compound represented by n=c=o to synthesize a terminal isocyanate compound, then reacting a component b comprising a diamine represented by the following formula (mb) to synthesize a terminal amine urea oligomer, and further reacting a component C comprising a tetracarboxylic dianhydride represented by the following formula (mc) or a derivative thereof, wherein a _2’ And A in the formula (2) defined in claim 1 _2’ Identical, A ₁ And A in the formula (1) defined in claim 1 ₁ Identical, said A ₁ 、A _1’ 、A _2’ And at least one of X has a partial structure represented by the formula (EG) in a molecule,

in the formula (mb), C ₁ 、C _1’ 、A _1’ Each with C in formula (1) as defined in claim 1 ₁ 、C _1’ 、A _1’ The same is true of the fact that,

in formula (mc), X is the same as X in formula (a) defined in claim 1.

15. A liquid crystal alignment film formed using the liquid crystal alignment agent according to any one of claims 1 to 12.

16. A liquid crystal display element comprising the liquid crystal alignment film according to claim 15.