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

Abstract

Provided is a liquid crystal alignment film which is used in low-temperature baking processes and which suppresses AC afterimage even when only a small amount of light irradiation is used in an alignment process using a photoalignment method. Also provided is a liquid crystal alignment film that exhibits good in-plane contrast uniformity.　This liquid crystal aligning agent contains at least one polymer (P) selected from the group consisting of: polyimide precursors obtained using a tetracarboxylic acid component that contains at least one selected from the group consisting of tetracarboxylic acid dianhydrides represented by formula (1) and derivatives thereof, and a diamine component that contains a diamine represented by formula (2-1), a diamine represented by formula (2-2), and a diamine represented by formula (2-3); and polyimides that are the imidation products of said polyimide precursors. (The meaning of each symbol in the formulas is as defined in the Description.)

Description

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

[0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element.

[0002] Liquid crystal display devices are widely used as display units for personal computers, smartphones, mobile phones, televisions, etc. Liquid crystal display devices typically include a liquid crystal layer sandwiched between a display element substrate and a color filter substrate, pixel electrodes and a common electrode that apply an electric field to the liquid crystal layer, an alignment film that controls the alignment of liquid crystal molecules in the liquid crystal layer, and thin film transistors (TFTs) that switch electric signals supplied to the pixel electrodes. Known driving methods for liquid crystal molecules include vertical electric field methods such as the TN method and the VA method, and horizontal electric field methods such as the IPS (In Plane Switching) driving method and the FFS (Fringe Field Switching) driving method.

[0003] The most widely used liquid crystal alignment films in industry are produced by rubbing the surface of a film made of polyamic acid and / or imidized polyimide formed on an electrode substrate in one direction with a cloth such as cotton, nylon, or polyester. Rubbing is a simple, highly productive, and industrially useful method. As an alternative to rubbing, a photoalignment method is known, in which polarized radiation is irradiated to impart liquid crystal alignment ability. Proposed photoalignment methods include those utilizing photoisomerization reactions, photocrosslinking reactions, and photodecomposition reactions (see, for example, Non-Patent Document 1, Patent Documents 1, 2, and 3).

[0004] Japanese Patent Laid-Open No. 9-297313 Japanese Patent Laid-Open No. 2004-206091 WO2017 / 047596

[0005] "Functional Materials," November 1997, Vol. 17, No. 11, pp. 13-22

[0006] In recent years, CO ２To reduce emissions, so-called low-temperature baking, in which baking is performed at a low temperature during the manufacturing process of liquid crystal alignment films, has been investigated. The baking process for producing polyimide-based liquid crystal alignment films requires particularly high temperatures compared to other processes for producing liquid crystal display elements. In addition to the environmental requirements mentioned above, the use of plastic substrates and the heat resistance required for color filters also necessitate the development of liquid crystal alignment agents capable of forming liquid crystal alignment films at baking temperatures of 200°C or less. Furthermore, with the prevalence of large-screen, high-resolution liquid crystal display elements and the increasing popularity of small display devices such as smartphones, tablet PCs, and car navigation systems, the demand for higher quality liquid crystal display elements is even greater than before. In particular, liquid crystal alignment films used in liquid crystal display elements, such as those in the IPS and FFS modes, require high alignment control to suppress image retention (hereinafter also referred to as AC image retention) caused by long-term AC drive. Furthermore, when performing alignment treatment using a photoalignment method, the amount of light irradiation is a factor that affects energy costs and production speed, so it is preferable to perform alignment treatment with a low amount of light irradiation. However, the inventors' investigations revealed that when conventional liquid crystal alignment agents are applied to a low-temperature baking process and light irradiation is performed under conditions of low exposure dose, it becomes difficult to obtain a liquid crystal alignment film with good in-plane contrast uniformity that suppresses AC afterimages to a high level and also suppresses the variation (non-uniformity) of the twist angle of the liquid crystal within the liquid crystal alignment film plane to a high level.

[0007] Therefore, in consideration of the above circumstances, the present invention aims to provide a liquid crystal alignment agent that can be applied to a low-temperature baking process and that can suppress AC afterimages to a high level even when the amount of light irradiation in alignment treatment by a photo-alignment method is small, and can obtain a liquid crystal alignment film with good in-plane uniformity of contrast, as well as the liquid crystal alignment film, and a liquid crystal display element using the liquid crystal alignment film.

[0008] The present inventors have conducted extensive research and have found that the above problems can be solved by using a liquid crystal aligning agent containing a specific component, thereby completing the present invention.

[0009] Specifically, the present invention has the following aspects.

[0010] A liquid crystal aligning agent comprising at least one polymer (P) selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid component containing at least one selected from the group consisting of tetracarboxylic acid dianhydrides represented by the following formula (1) and derivatives thereof, and a diamine component containing a diamine represented by the following formula (2-1), a diamine represented by the following formula (2-2), and a diamine represented by the following formula (2-3), and a polyimide which is an imidized product of the polyimide precursor:

[0011]

[0012] (In formula (1), R １ ~R ４ 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 and containing a fluorine atom, or a phenyl group; R １ ~R ４ At least one of represents a group other than a hydrogen atom as defined above. In formula (2-1), n1 is an integer of 1 or 3. The benzene ring bonded to the amino group is unsubstituted, or one or more hydrogen atoms on the benzene ring are substituted with a monovalent group. However, when n1 is 1, the monovalent group is a monovalent group other than a methyl group or a fluorine atom. Z １ are each independently a hydrogen atom, or an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms, which may have a substituent. ２１ , R ２２ are each independently a hydrogen atom, a methyl group, or a fluorine atom; R ２１ , R ２２ At least one of Z represents a methyl group or a fluorine atom. ２ are each independently a hydrogen atom, or an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted alkenyl group having 2 to 6 carbon atoms, or an optionally substituted aralkyl group having 7 to 13 carbon atoms. n2 is an integer of 1 or 2. In formula (2-3), D Ｎ represents a monovalent organic group having a thermally detachable group. ３are each independently a hydrogen atom, or an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted alkenyl group having 2 to 6 carbon atoms, or an optionally substituted aralkyl group having 7 to 13 carbon atoms.) Throughout this specification, examples of halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and * represents a bond. Boc represents a tert-butoxycarbonyl group. Also, "tert-" can be referred to as "t-".

[0013] By using the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal alignment film that can be applied to a low-temperature baking process and that suppresses AC afterimages to a high level even when the amount of light irradiation in the alignment treatment by a photoalignment method is small.In addition, it is possible to obtain a liquid crystal alignment film that has good in-plane uniformity of contrast.

[0014] 1 is a schematic cross-sectional view showing an example of a lateral electric field mode liquid crystal display element of the present invention, and FIG. 2 is a schematic cross-sectional view showing another example of a lateral electric field mode liquid crystal display element of the present invention.

[0015] <Polymer (P)> The liquid crystal aligning agent of the present invention contains at least one polymer (P) selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic acid component containing at least one selected from the group consisting of tetracarboxylic acid dianhydrides represented by the above formula (1) and derivatives thereof (also referred to as a specific alicyclic tetracarboxylic acid component (p) in the present invention), a diamine component containing a diamine represented by the above formula (2-1) (also referred to as a specific diamine (1) in the present invention), a diamine represented by the above formula (2-2) (also referred to as a specific diamine (2) in the present invention), and a diamine represented by the above formula (2-3) (also referred to as a specific diamine (3) in the present invention), and a polyimide which is an imidized product of the polyimide precursor. The polymer (P) may be one or more types. Here, examples of the polyimide precursor include, but are not limited to, polymers that can be obtained by imidizing polyamic acids, polyamic acid esters, etc. (Tetracarboxylic Acid Component) The polyamic acid (P'), which is a polyimide precursor of the polymer (P), can be obtained, for example, by a polymerization reaction between the specific diamine component and the tetracarboxylic dianhydride represented by the formula (1). When producing the polymer (P), the tetracarboxylic acid component to be reacted with the diamine component may be not only a tetracarboxylic acid dianhydride, but also a derivative of a tetracarboxylic acid dianhydride such as a tetracarboxylic acid, a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester, or a tetracarboxylic acid dialkyl ester dihalide. １ ~R ４ Specific examples of the alkyl group having 1 to 6 carbon atoms in the above R include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and an n-pentyl group. １ ~R ４ Specific examples of the alkenyl group having 2 to 6 carbon atoms in the above R include a vinyl group, a propenyl group, and a butenyl group, which may be linear or branched. １ ~R ４Specific examples of the alkynyl group having 2 to 6 carbon atoms in the above R include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, and a 3-butynyl group. １ ~R ４ In the above formula, examples of the monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom include a fluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, a pentafluoropropyl group, a trifluoromethoxy group, a 2,2,2-trifluoroethyl group, and a 2,2,2-trifluoroethoxy group. １ ~R ４ It is more preferable that at least two of R represent a group other than a hydrogen atom as defined above. １ and R ４ represents a group other than a hydrogen atom, and R ２ and R ３ It is more preferable that R represents a hydrogen atom. １ ~R ４ are each independently a hydrogen atom or a methyl group, and R １ ~R ４ More preferably, at least one of R is a methyl group. １ ~R ４ It is more preferred that at least two of R are methyl groups. １ and R ４ is a methyl group, and R ２ and R ３is a hydrogen atom. The proportion of the specific alicyclic tetracarboxylic acid component (p) used is more preferably 10 mol% or more, even more preferably 20 mol% or more, and most preferably 50 mol% or more, relative to 1 mole of all tetracarboxylic acid components used in polymer (P). The tetracarboxylic acid components used in producing polymer (P) may contain tetracarboxylic acid components other than the specific alicyclic tetracarboxylic acid component (p) (hereinafter also referred to as other tetracarboxylic acid components). When other tetracarboxylic acid components are used in addition to the specific alicyclic tetracarboxylic acid component (p), the content of the specific alicyclic tetracarboxylic acid component (p) is more preferably 95 mol% or less, even more preferably 90 mol% or less, relative to 1 mole of all tetracarboxylic acid components used in polymer (P). Furthermore, the content of the other tetracarboxylic acid components is more preferably 5 mol% to 90 mol%, even more preferably 10 to 80 mol%, and most preferably 10 to 50 mol%, relative to 1 mole of all tetracarboxylic acid components used in polymer (P). Examples of the other tetracarboxylic acid component include acyclic aliphatic tetracarboxylic acid dianhydrides, alicyclic tetracarboxylic acid dianhydrides other than the tetracarboxylic acid dianhydride represented by the above formula (1), aromatic tetracarboxylic acid dianhydrides, and derivatives thereof. Here, the acyclic aliphatic tetracarboxylic acid dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups bonded to a chain hydrocarbon structure. However, it does not have to be composed only of a chain hydrocarbon structure, and may have an alicyclic structure or an aromatic ring structure as part of it.

[0016] The alicyclic tetracarboxylic acid dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to the alicyclic structure. However, none of these four carboxy groups are bonded to an aromatic ring. Furthermore, it is not necessary for the structure to be composed solely of an alicyclic structure; it may also have a chain hydrocarbon structure or an aromatic ring structure as part of it. The aromatic tetracarboxylic acid dianhydride is not particularly limited as long as it is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to the aromatic ring. The acyclic aliphatic or alicyclic tetracarboxylic acid dianhydride or a derivative thereof is preferably a tetracarboxylic acid dianhydride or a derivative thereof 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, from the viewpoint of improving liquid crystal alignment. The aromatic tetracarboxylic acid dianhydride or a derivative thereof is preferably a tetracarboxylic acid dianhydride or a derivative thereof having a benzene ring structure, from the viewpoint of improving liquid crystal alignment. Specific examples of tetracarboxylic acid dianhydrides or derivatives thereof that can be used for the other tetracarboxylic acid component include the following: 1,2,3,4-butanetetracarboxylic dianhydride, or (Q) ２ -A (Q represents a monovalent succinic anhydride structure, and A represents -CH ２ -, an alkylene group having 2 to 18 carbon atoms, or -CH contained in the alkylene group ２represents a divalent organic group in which a portion of - is replaced by at least one group selected from the group consisting of a phenylene group, -O-, -NR- (R represents a hydrogen atom or a methyl group), -C(=O)-NR- (R represents a hydrogen atom or a methyl group), -C(=O)-O-, and -O-C(=O)-.acyclic aliphatic tetracarboxylic acid dianhydrides such as 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,2,3,4-cyclopentane tetracarboxylic acid dianhydride, 1,2,4,5-cyclohexane tetracarboxylic acid dianhydride, 3,3',4,4'-dicyclohexyl tetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, 5-(2,5-dioxotetrahydrofuran- 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride Alicyclic tetracarboxylic dianhydrides such as pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-diphenylethertetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4 aromatic tetracarboxylic acid dianhydrides such as 4,4'-bis(3,4-dicarboxyphenoxy)-2,2-diphenylpropane dianhydride, ethylene glycol bisanhydrotrimellitate, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 4,4'-carbonyldiphthalic anhydride, 4,4'-(1,4-phenylenedioxy)bis(phthalic anhydride), and 4,4'-(1,4-phenylenedimethylene)bis(phthalic anhydride); and other tetracarboxylic acid dianhydrides such as those described in JP 2010-97188 A. (Specific Diamine (1)) The specific diamine (1) of the present invention is a diamine represented by the above formula (2-1).The specific diamine (1) may be used alone or in combination of two or more. In the formula (2-1), one or more hydrogen atoms on the benzene ring bonded to the amino group may be substituted with a monovalent group, and examples of the monovalent group include a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, an alkyloxycarbonyl group having 2 to 3 carbon atoms, a cyano group, and a nitro group. However, in the formula (2-1), when n1 is 1, the monovalent group is a monovalent group other than a methyl group or a fluorine atom. Z in the formula (2-1) may be substituted with a monovalent group other than a methyl group or a fluorine atom. １ In the above formula (2-1), the "alkyl group having 1 to 6 carbon atoms" includes a monovalent group of a linear, branched, or cyclic aliphatic saturated hydrocarbon having 1 to 6 carbon atoms. Preferred examples include a methyl group, an ethyl group, a propyl group, a butyl group, a t-butyl group, a hexyl group, a cyclopentyl group, a cyclohexyl group, and a bicyclohexyl group. １ The "alkenyl group having 2 to 6 carbon atoms" in the above formula (2-1) includes a monovalent group of a linear, branched, or cyclic aliphatic unsaturated hydrocarbon having 2 to 6 carbon atoms and one or more carbon-carbon double bonds. Preferred specific examples include a vinyl group, an allyl group, a 1-propenyl group, an isopropenyl group, a 2-butenyl group, a 1,3-butadienyl group, a 2-pentenyl group, a 2-hexenyl group, a cyclopropenyl group, a cyclopentenyl group, or a cyclohexenyl group. １ The "alkynyl group having 2 to 6 carbon atoms" in the formula (2-1) includes a monovalent group of a linear, branched, or cyclic aliphatic unsaturated hydrocarbon having 2 to 6 carbon atoms and one or more carbon-carbon triple bonds. Preferred specific examples include an ethynyl group, a 1-propynyl group, and a 2-propynyl group. １ Examples of the aralkyl group having 7 to 13 carbon atoms in Z include a benzyl group and a phenethyl group. １Examples of the substituent that the alkyl group, alkenyl group, alkynyl group, or aralkyl group in the formula (2-1) may have include, but are not limited to, a halogen atom, a hydroxyl group, a thiol group, a nitro group, an organoxy group, an organothio group, an organosilyl group, an acyl group, an ester group, a thioester group, a phosphate ester group, an amide group, etc. Specific examples of more preferred diamines represented by the formula (2-1) include bis(4-aminophenoxy)methane and 1,3-bis(4-aminophenoxy)propane.

[0017] The content of the specific diamine (1) is preferably 5 mol % or more, more preferably 10 mol % or more, based on 1 mol of the diamine component used in the production of the polymer (P). (Specific diamine (2)) The specific diamine (2) of the present invention is a diamine represented by the above formula (2-2). The specific diamine (2) may be used alone or in combination of two or more. Z in the above formula (2-2) ２ Specific examples of the above are Z in the formula (2-1). １ More preferred specific examples of the diamine represented by formula (2-2) above include bis(4-amino-2-methylphenoxy)methane, bis(4-amino-3-methylphenoxy)methane, bis(4-amino-2-fluorophenoxy)methane, bis(4-amino-3-fluorophenoxy)methane, 1,2-bis(4-amino-2-methylphenoxy)ethane, 1,2-bis(4-amino-3-methylphenoxy)ethane, 1,2-bis(4-amino-2-fluorophenoxy)ethane, 1,2-bis(4-amino-3-fluorophenoxy)ethane, and diamines represented by the following formulas (2-2-1) to (2-2-4).

[0018]

[0019] (In the above formula, n2 has the same definition as n2 in formula (2-2).) The content of the specific diamine (2) is preferably 5 mol % or more, more preferably 10 mol % or more, relative to 1 mol of the diamine component used in the production of the polymer (P). (Specific diamine (3)) The specific diamine (3) of the present invention is a diamine represented by the above formula (2-3). The specific diamine (3) may be used alone or in combination of two or more. Z in the above formula (2-3) ３ Specific examples of the above are Z in the formula (2-1). １ Specific examples are those given in the explanation of formula (2-3), and preferred examples are also the same. Ｎrepresents a monovalent organic group having a thermally detachable group. The thermally detachable group is preferably bonded to a heteroatom, and examples of such heteroatoms include a nitrogen atom and an oxygen atom. Specific examples of thermally detachable groups bonded to a nitrogen atom include a carbamate protecting group, an amide protecting group, an imide protecting group, and a sulfonamide protecting group. Of these, carbamate protecting groups are preferred in terms of their high thermal detachability, and specific examples thereof include a Boc group, a benzyloxycarbonyl group, a 1,1-dimethyl-2-haloethyloxycarbonyl group, a 1,1-dimethyl-2-cyanoethyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, an allyloxycarbonyl group, and a 2-(trimethylsilyl)ethoxycarbonyl group. Of these, a Boc group is particularly preferred in terms of its excellent thermal detachability. Specific examples of the thermally detachable group bonded to an oxygen atom include ether-based protecting groups such as methyl, ethyl, t-butyl, benzyl, p-methoxybenzyl, and trityl groups; acetal-based protecting groups such as methoxymethyl, ethoxyethyl, and 2-tetrahydropyranyl groups; acyl-based protecting groups such as acetyl, pivaloyl, benzoyl, and trichloroacetyl groups; allyl-based protecting groups such as allyl and methallyl groups; carbamate-based protecting groups such as Boc groups; and silyl ether-based protecting groups such as trimethylsilyl, triethylsilyl, and t-butyldimethylsilyl groups. From the viewpoint of ease of detachment by heat, the thermally detachable group is preferably a methyl, ethyl, t-butyl, benzyl, 2-tetrahydropyranyl, methoxymethyl, 1-ethoxyethyl, or acetyl group. Ｎ is preferably a monovalent organic group (D) represented by the following formula (D).

[0020] In the monovalent organic group (D), Q represents a single bond or a divalent linking group, and R represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms (excluding thermally labile groups). D represents a thermally labile group. n is an integer of 1 or 2. From the viewpoint of suitably obtaining the effects of the present invention, R is preferably an alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group, or a hydrogen atom, and more preferably a hydrogen atom. The divalent linking group in Q is preferably -C(=O)- or a divalent organic group having 1 to 10 carbon atoms. Specific examples of divalent organic groups having 1 to 10 carbon atoms include -CH ２ -, or an alkylene group having 2 to 10 carbon atoms, provided that any -CH ２ - represents -O-, -O-C(=O)-, -C(=O)-, -N(R')- (R' represents a hydrogen atom or a methyl group), -N(R')-C(=O)- (R' represents a hydrogen atom or a methyl group), -CR ７ =CR ８ - (R ７ , R ８ represents a hydrogen atom, a methyl group, a methoxy group, or a halogen atom. ) or -C≡C- may be substituted. More preferred examples of the divalent linking group in Q include the following structures. Note that n1 to n5 are each independently an integer of 1 to 5. Also, *1 is bonded to a benzene ring, and *2 is bonded to a nitrogen atom. *1-(CH ２ ) ｎ１ -*2, *1-O-(CH ２ ) ｎ２ -*2, *1-C(=O)-O-(CH ２ ) ｎ３ -*2, *1-OC(=O)-(CH ２ ) ｎ４ -*2, *1-C(=O)-NH-(CH ２ ) ｎ５ -*2.

[0021] The content of the specific diamine (3) is preferably 5 mol% or more, more preferably 10 mol% or more, per mole of the diamine component used in the production of the polymer (P). The diamine component used in the production of the polymer (P) may contain diamines other than the specific diamines (1) to (3) (hereinafter also referred to as other diamines). When other diamines are used in addition to the specific diamines (1) to (3), the total content of the specific diamines (1) to (3) relative to the diamine component is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less, per mole of the diamine component used in the production of the polymer (P). Examples of other diamines are listed below, but are not limited to these. The other diamines may be used alone, in combination of two or more, or in combination of three or more. Phenylenediamines such as p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, and 2,6-diaminotoluene; 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'- diaminobiphenyl compounds such as diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, and 2,3'-diaminobiphenyl; ＡＬ ) (excluding the specific diamines (1) and (2). Preferably, ＡＬ -1) to (d ＡＬdiamines represented by the formula (I-9), 1,7-bis(4-aminophenoxy)heptane, 1,7-bis(3-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1,8-bis(3-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,9-bis(3-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, 1,10-bis(3-aminophenoxy)decane, decane, 1,11-bis(4-aminophenoxy)undecane, 1,11-bis(3-aminophenoxy)undecane, 1,12-bis(4-aminophenoxy)dodecane, 1,12-bis(3-aminophenoxy)dodecane, 1,2-bis(6-amino-2-naphthyloxy)ethane, 1,2-bis(6-amino-2-naphthyl)ethane, or 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine. ), 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene, and other diamines having a diphenyl ether structure (hereinafter, these are collectively referred to as first diamines) diamines having a tetracarboxylic acid diimide structure, such as N,N'-bis(4-aminophenyl)-cyclobutane-(1,2,3,4)-tetracarboxylic acid diimide, N,N'-bis(4-aminophenyl)-1,3-dimethylcyclobutane-(1,2,3,4)-tetracarboxylic acid diimide, and N,N'-bis(2,2'-bis(trifluoromethyl)-4'-amino-1,1'-biphenyl-4-yl)-cyclobutane-(1,2,3,4)-tetracarboxylic acid diimide;aromatic diamines having an azobenzene structure such as 4,4'-diaminoazobenzene, aromatic diamines having a stilbene structure such as 4,4'-diaminostilbene, aromatic diamines having a tolan structure such as diaminotlan, aromatic diamines having a chalcone structure such as 4,4'-diaminochalcone, aromatic diamines having a phenylbenzoate structure such as 1,4-phenylenebis(4-aminobenzoate), 1,4-phenylenebis(3-aminobenzoate), 1,3-phenylenebis(4-aminobenzoate), 1,3-phenylenebis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4-aminophenyl)isophthalate, bis(3-aminophenyl)isophthalate, or (E)-4-aminophenyl 3-(4-aminophenyl)acrylate, (E)-4-amino-2-methylphenyl 3-(4-aminophenyl)acrylate, (E)-4-aminophenethyl Diamines having a photoalignment group, typified by aromatic diamines having a cinnamate structure, such as 3-(4-aminophenyl)acrylate, (E,E)-bis-(4'-aminophenyl) 1,3-benzenediacrylate, (E,E)-bis-(4'-aminophenyl) 1,4-benzenediacrylate, or 4-aminophenyl (2E)-3-(4-aminophenyl)-2-methyl-2-propenoate; diamines having a photopolymerizable group at the terminal, such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallylaniline; 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone, 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl Diamines having a radical polymerization initiator function, such as 3,5-diaminobenzoate; diamines having an amide bond, such as 4,4'-diaminobenzanilide; and diamines having a urea bond, such as 1,3-bis(4-aminophenyl)urea, 1,3-bis(4-aminobenzyl)urea, and 1,3-bis(4-aminophenethyl)urea;2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(3-amino-4-methylphenyl)propane, 4,4'-diaminobenzophenone , 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene; 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, N-[3-(1H-imidazol-1-yl)propyl] Heterocycle-containing diamines such as 3,5-diaminobenzamide, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-4-methyl-2-oxazolyl]-benzenamine, or diamines represented by the following formulas (z-1) to (z-13), or 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, diamines represented by the following formula (z-14), N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, or N diamines having at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocycle, a secondary amino group, and a tertiary amino group (hereinafter also referred to as a specific nitrogen atom-containing structure, provided that the specific nitrogen atom-containing structure is a functional group other than the two amino groups involved in the polycondensation reaction), typified by diamines having a diphenylamine structure such as N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-benzenediamine (provided that the molecule does not have an amino group bonded with a protecting group that is cleaved by heating and replaced with a hydrogen atom);2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diamino-3,3'-dihydroxybiphenyl; 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 1,2-bis(4-aminophenyl)ethane-3-carboxylic acid, 4,4'-diaminobiphenyl-3,3'-di Carboxylic acids, diamines having a carboxy group such as 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, 3,3'-diaminobiphenyl-4,4'-dicarboxylic acid, 3,3'-diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid, 1,2-bis(4-aminophenyl)ethane-3,3'-dicarboxylic acid, and 4,4'-diaminodiphenylether-3,3'-dicarboxylic acid; 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 1-(4-amino 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indan-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-6-amine; diamines having the group "-N(D)-" (D represents a protecting group which is eliminated by heating and replaced with a hydrogen atom, preferably a carbamate protecting group, more preferably a tert-butoxycarbonyl group, excluding the above-mentioned specific diamines) such as those of the following formulas (5-1) to (5-8) (excluding the specific diamine (3)); diamines having a steroid skeleton such as cholestenyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestanyl 3,5-diaminobenzoate, lanostannyl 3,5-diaminobenzoate, and 3,6-bis(4-aminobenzoyloxy)cholestane; diamines represented by the following formulae (V-1) and (V-2); aromatic diamines represented by diamines having a fluorene skeleton such as 2,7-diaminofluorene or 9,9-bis(4-aminophenyl)fluorene;Diamines having a siloxane bond, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; acyclic aliphatic diamines typified by metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, etc.; alicyclic diamines typified by 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), etc., as well as diamines in which two amino groups are bonded to a group represented by any one of formulas (Y-1) to (Y-167) described in WO2018 / 117239, etc.;

[0022]

[0023] (Ar １ , and Ar １’ represents a benzene ring, a biphenyl structure, or a naphthalene ring, and one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring may be unsubstituted or substituted with a monovalent group. １ and L １’ respectively represent a single bond, —O—, —C(═O)—, or —O—C(═O)—. A is —CH ２ A represents an alkylene group having 2 to 12 carbon atoms, or a divalent organic group in which at least one of -O-, -C(=O)-O-, and -O-C(=O)- is inserted between the carbon-carbon bonds of the alkylene group. Any hydrogen atom possessed by A may be substituted with a halogen atom.

[0024] One or more hydrogen atoms on the benzene ring, biphenyl structure, or naphthalene ring may be substituted with a monovalent group, and examples of the monovalent group include a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, an alkyloxycarbonyl group having 2 to 3 carbon atoms, a cyano group, and a nitro group. １ -A-L １’ - is -O-(CH ２ ) ２ When —O— is represented, the monovalent group is R２１ , R ２２ represents a substituent different from Ar １ and Ar １’ In the above formula, the bonding positions of the benzene ring in which any hydrogen atom on the ring may be substituted are preferably the 1st and 4th positions, the bonding positions of the biphenyl structure in which any hydrogen atom on the ring may be substituted are preferably the 4th and 4'-positions, and the bonding positions of the naphthalene ring in which any hydrogen atom on the ring may be substituted are preferably the 2nd and 6th positions.

[0025]

[0026] (Formula (d ＡＬ In formula (d-2), the sum of l, m, and n is 1 to 12. ＡＬ In formula (d-5), the sum of m1, m2 and n is 1 to 12. ＡＬ In formula (d-7), the sum of m1, m2 and n is 3 to 12. ＡＬ In formula (d-8), m1 and m2 may be the same or different. ＡＬ -9) The sum of l, m, and n is 3 to 12.

[0027]

[0028]

[0029]

[0030]

[0031] In the formula (V-1), m and n are integers of 0 to 3, and satisfy the relationship 1≦m+n≦4. j is an integer of 0 or 1. X １ is -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CO-N(CH ３ )-, -NH-, -O-, -CH ２ O-, -CH ２ represents —OCO—, —COO—, or —OCO—. １represents a monovalent group such as a fluorine atom, a fluorine atom-containing alkyl group having 1 to 10 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkoxyalkyl group having 2 to 10 carbon atoms. ２ is -O-, -CH ２ O-, -CH ２ m, n, and X represent —OCO—, —COO—, or —OCO—. １ , R １ When two occur, each independently has the above definition.

[0032] Examples of the nitrogen atom-containing heterocycle that the diamine having the 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, and hexamethyleneimine. Among these, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, and acridine are preferred.

[0033] From the viewpoint of enhancing liquid crystal alignment, the other diamine may be a diamine selected from the group consisting of the first diamine, a diamine having a tetracarboxylic diimide structure, a diamine having an amide bond, a diamine having a urea bond, and a diamine having a group "-N(D)-". The content of the other diamine is preferably 5 to 85 mol%, more preferably 10 to 80 mol%, and even more preferably 15 to 80 mol%, relative to 1 mol of the diamine component used in the production of the polymer (P). Furthermore, when two or more other diamines are contained, the content of each diamine constituting each other diamine may be 30 mol% or less. (Liquid Crystal Alignment Agent) The liquid crystal aligning agent of the present invention is a liquid composition obtained by dispersing or dissolving the polymer (P) and other components used as needed, preferably in a suitable solvent.

[0034] The liquid crystal aligning agent of the present invention may contain other polymers other than the polymer (P). Specific examples of other polymers include, in addition to the polymer (P), at least one polymer selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic acid component that does not contain the specific alicyclic tetracarboxylic acid component (p) and a polyimide that is an imidized product of the polyimide precursor, at least one polymer selected from the group consisting of a polyimide precursor obtained using a diamine component that does not contain any of the specific diamines (1) to (3) and a polyimide that is an imidized product of the polyimide precursor (also referred to as polymer (B) in the present invention), polysiloxane, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly(styrene-maleic anhydride) copolymer, poly(isobutylene-maleic anhydride) copolymer, poly(vinyl ether-maleic anhydride) copolymer, poly(styrene-phenylmaleimide) derivative, and a polymer selected from the group consisting of poly(meth)acrylate.

[0035] Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley Corporation) and GSM301 (manufactured by Gifu Ceramics Manufacturing Co., Ltd.), and a specific example of poly(isobutylene-maleic anhydride) copolymers includes ISOBAN-600 (manufactured by Kuraray Co., Ltd.). A specific example of poly(vinyl ether-maleic anhydride) copolymers includes Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland Corporation).

[0036] Of the above other polymers, the polymer (B) is more preferred from the viewpoint of reducing afterimages resulting from residual DC.

[0037] The other polymers may be used alone or in combination of two or more. The content of the other polymers is preferably 90 parts by mass or less, more preferably 10 to 90 parts by mass, and even more preferably 20 to 80 parts by mass, relative to 100 parts by mass of the total polymers contained in the liquid crystal aligning agent. (Polymer (B)) Specific examples of the tetracarboxylic acid component used in the production of the polymer (B), including preferred examples, include the same compounds as those exemplified for the polymer (P), such as acyclic aliphatic tetracarboxylic acid dianhydrides, alicyclic tetracarboxylic acid dianhydrides, aromatic tetracarboxylic acid dianhydrides, or derivatives thereof. The tetracarboxylic acid component used in the production of the polymer (B) more preferably contains a tetracarboxylic acid dianhydride or a derivative thereof having at least one partial structure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring (hereinafter, these may also be referred to as specific tetracarboxylic acid component (B)).

[0038] The content of the specific tetracarboxylic acid component (B) is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 50 mol% or more, based on 1 mol of all tetracarboxylic acid components used in the production of the polymer (B).

[0039] Examples of the diamine component for obtaining the polymer (B) include the diamines exemplified for the polymer (P) above. Among them, the first diamine, a diamine having a urea bond, a diamine having an amide bond, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl) ... It is preferable that the diamine component contains at least one diamine selected from the group consisting of 2-bis(3-amino-4-methylphenyl)propane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, the diamines having the specific nitrogen atom-containing structure, the diamines having a carboxy group, 4-(2-(methylamino)ethyl)aniline, and 4-(2-aminoethyl)aniline (in the present invention, these are also referred to as specific diamine (b)). As the diamine component, one diamine may be used alone, or two or more diamines may be used in combination.

[0040] When the specific diamine (b) is used, its content is preferably 10 mol% or more, more preferably 20 mol% or more, of the total diamine components used in the production of polymer (B). When a diamine other than specific diamine (b) is used, the content of specific diamine (b) is preferably 90 mol% or less, more preferably 80 mol% or less, per mole of the total diamine components used in the production of polymer (B). (Production of Polyamic Acid) Polyamic acid is produced by reacting a diamine component with a tetracarboxylic acid component in an organic solvent. The ratio of the tetracarboxylic acid component and diamine component used in the polyamic acid production reaction is preferably 0.5 to 2 equivalents of acid anhydride groups in the tetracarboxylic acid component per equivalent of amino groups in the diamine component, more preferably 0.8 to 1.2 equivalents. As with a typical polycondensation reaction, the closer the equivalent of acid anhydride groups in the tetracarboxylic acid component is to 1 equivalent, the higher the molecular weight of the resulting polyamic acid.

[0041] The reaction temperature in the production of polyamic acid is preferably −20 to 150° C., more preferably 0 to 100° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours. The production of polyamic acid can be carried out at any concentration, but the concentration of polyamic acid is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration in the early stages, and then a solvent can be added.

[0042] Specific examples of the organic solvent include cyclohexanone, cyclopentanone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolidinone. Furthermore, when the polymer has high solvent solubility, solvents such as methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether can be used. (Production of Polyamic Acid Esters) Polyamic acid esters can be obtained by known methods, such as [I] a method of reacting the polyamic acid obtained by the above method with an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester with a diamine, or [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine. (Production of Polyimides) Polyimides can be obtained by ring-closing (imidizing) a polyimide precursor such as the above polyamic acid or polyamic acid ester. The imidization ratio, as used herein, refers to the proportion of imide groups in the total amount of imide groups derived from tetracarboxylic acid dianhydrides or their derivatives and carboxy groups (or their derivatives). From the viewpoint of improving handleability and liquid crystal alignment, the imidization ratio is preferably 80 to 95%, more preferably 82 to 95%, and even more preferably 85 to 95%.

[0043] Methods for imidizing the polyimide precursor include thermal imidization, in which a solution of the polyimide precursor is heated as is, and catalytic imidization, in which a catalyst is added to a solution of the polyimide precursor.

[0044] When the polyimide precursor is thermally imidized in a solution, the temperature is preferably 100 to 400°C, more preferably 120 to 250°C, and it is preferable to carry out the imidization while removing water produced by the imidization reaction from the system.

[0045] Catalytic imidization of polyimide precursors can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring the mixture at preferably -20 to 250°C, more preferably 0 to 180°C. The amount of the basic catalyst is preferably 0.5 to 30 times, more preferably 2 to 20 times, the molar ratio of the amic acid groups, and the amount of the acid anhydride is preferably 1 to 50 times, more preferably 3 to 30 times, the molar ratio of the amic acid groups. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Of these, pyridine is preferred because it has adequate basicity for promoting the reaction. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Of these, acetic anhydride is preferred because it facilitates purification after the reaction. The imidization rate by catalytic imidization can be controlled by adjusting the catalyst amount, reaction temperature, and reaction time.

[0046] To recover the produced polyimide precursor or polyimide from a reaction solution of a polyimide precursor or polyimide, the reaction solution may be precipitated by pouring the reaction solution into a solvent. Examples of solvents used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer precipitated by pouring into the solvent can be recovered by filtration and then dried at room temperature or by heating under atmospheric or reduced pressure. Furthermore, the recovered polymer can be redissolved in an organic solvent and reprecipitated and recovered 2 to 10 times to reduce the amount of impurities in the polymer. Examples of solvents used in this process include alcohols, ketones, and hydrocarbons. Using three or more solvents selected from these solvents is preferred because it further increases the efficiency of purification.

[0047] In producing the polyimide precursor or polyimide of the present invention, a terminal-capping polymer may be produced using a tetracarboxylic acid component containing a tetracarboxylic acid dianhydride or a derivative thereof, a diamine component containing a diamine, and an appropriate terminal-capping agent. The terminal-capping polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by coating and improving the adhesion properties between the sealant and the liquid crystal alignment film.

[0048] Examples of the terminals of the polyimide precursor or polyimide in the present invention include an amino group, a carboxy group, an acid anhydride group, or a group derived from an end-capping agent described below. The amino group, carboxy group, and acid anhydride group can be obtained by a conventional condensation reaction or by blocking the terminals with the following end-capping agents.

[0049] Examples of the end-capping agent include acid anhydrides such as acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, and 4-ethynylphthalic anhydride; dicarbonate diester compounds such as di-tert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinic acid chloride; Examples of the amino acid include 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 isocyanates having an unsaturated bond such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, 2-acryloyloxyethyl isocyanate, and 2-methacryloyloxyethyl isocyanate.

[0050] The proportion of the end-capping agent used is preferably 0.01 to 20 parts by mole, and more preferably 0.01 to 10 parts by mole, per 100 parts by mole of the total of the diamine components used.

[0051] The polystyrene-equivalent weight average molecular weight (Mw) of the polyimide precursor and polyimide measured by gel permeation chromatography (GPC) is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. The molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC, is preferably 15 or less, more preferably 10 or less. By having the molecular weight within this range, good liquid crystal alignment properties can be ensured in liquid crystal display elements.

[0052] The organic solvent contained in the liquid crystal aligning agent according to the present invention is not particularly limited as long as it can uniformly dissolve the polymer (P) and other polymers added as needed. Examples of the organic solvent include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N,N-dimethylpropionamide, tetramethylurea, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropanamide, and the like. Examples of suitable solvents include N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone (collectively referred to as "good solvents"). Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, and γ-butyrolactone are preferred. The content of the good solvent is preferably 20 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass of the total solvent contained in the liquid crystal aligning agent.

[0053] Furthermore, the organic solvent contained in the liquid crystal aligning agent is preferably a mixed solvent containing, in addition to the above solvent, a solvent (also referred to as a poor solvent) that improves the coatability and surface smoothness of the coating film when the liquid crystal aligning agent is applied. Specific examples of poor solvents are listed below, but are not limited to these. The content of the poor solvent is preferably 1 to 80 mass %, more preferably 10 to 80 mass %, and particularly preferably 20 to 70 mass %, of the total solvent contained in the liquid crystal aligning agent. The type and content of the poor solvent are appropriately selected depending on the coater, coating conditions, coating environment, etc. of the liquid crystal aligning agent.

[0054] Examples of poor solvents include diisopropyl ether, diisobutyl ether, diisobutyl carbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol ethanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene Glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, cyclohexyl acetate, 4-methyl-2-pentyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone), and the like.

[0055] Of these, diisobutyl carbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, or diisobutyl ketone is preferred.

[0056] Preferred solvent combinations of a good solvent and a poor solvent include N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, and N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether. Coal diacetate, N,N-dimethyl lactamide and diisobutyl ketone, N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate, N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate, N-methyl-2-pyrrolidone, ethyl 3-ethoxypropionate and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone, ethyl 3-ethoxypropionate and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, ethyl 3-ethoxypropionate and diethylene glycol mono propyl ether, N-ethyl-2-pyrrolidone, ethyl 3-ethoxypropionate, and diethylene glycol monopropyl ether, N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate, N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether, N,N-dimethyl lactamide and ethylene glycol monobutyl ether, N,N-dimethyl lactamide and propylene glycol diacetate, N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether, N-ethyl-2 -pyrrolidone, diethylene glycol monoethyl ether, and butyl cellosolve acetate, N-methyl-2-pyrrolidone, diethylene glycol monomethyl ether, and butyl cellosolve acetate, N,N-dimethyl lactamide and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, and 4-hydroxy-4-methyl-2-pentanone,N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and dipropylene glycol monomethyl ether Methyl-2-pentanone and propylene glycol diacetate, N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol dimethyl ether, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone, N-methyl-2-pi rolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisopropyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisobutylcarbinol, N-methyl-2-pyrrolidone, γ-butyrolactone, and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol pyrene glycol monomethyl ether, N-ethyl-2-pyrrolidone, diethylene glycol diethyl ether, and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and propylene glycol diacetate, N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and diisobutyl ketone, N-ethyl-2-pyrrolidone, γ-butyrolactone, and diisobutyl ketone, N-ethyl-2-pyrrolidone, N,N-dimethyl lactamide, and diisobutyl ketone,Examples of the polymers include N-methyl-2-pyrrolidone, ethylene glycol monobutyl ether, and ethylene glycol monobutyl ether acetate, γ-butyrolactone, ethylene glycol monobutyl ether acetate, and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone, ethylene glycol monobutyl ether acetate, and propylene glycol dimethyl ether, N-methyl-2-pyrrolidone, 4-methyl-2-pentyl acetate, and ethylene glycol monobutyl ether, N-ethyl-2-pyrrolidone, cyclohexyl acetate, and 4-hydroxy-4-methyl-2-pentanone, cyclohexanone, and propylene glycol monomethyl ether, cyclopentanone, and propylene glycol monomethyl ether, and N-methyl-2-pyrrolidone, cyclohexanone, and propylene glycol monomethyl ether. (Liquid Crystal Alignment Agent) The liquid crystal aligning agent of the present invention contains the polymer (P) and, if necessary, the other polymers described above, and the organic solvent. The total content of polymers contained in the liquid crystal aligning agent of the present invention can be appropriately changed depending on the thickness of the coating film to be formed, but is preferably 1% by mass or more from the viewpoint of forming a uniform and defect-free coating film, and is preferably 10% by mass or less from the viewpoint of storage stability of the solution. A particularly preferred total content of polymers is 2 to 8% by mass.

[0057] The content of the polymer (P) used in the present invention is preferably 1 to 100% by mass, more preferably 10 to 100% by mass, and particularly preferably 20 to 100% by mass, relative to the total amount of polymers contained in the liquid crystal aligning agent. In addition to the polymer (P), the other polymers, and the organic solvent, the liquid crystal aligning agent of the present invention may contain other components (hereinafter also referred to as additive components). Examples of such additive components include at least one crosslinking compound selected from the group consisting of a crosslinking compound having at least one substituent selected from an oxiranyl group, an oxetanyl group, a blocked isocyanate group, an oxazoline group, a cyclocarbonate group, a hydroxyalkyl group, and an alkoxy group, and a crosslinking compound having a polymerizable unsaturated group; a functional silane compound; a metal chelate compound; a curing accelerator; a surfactant; an antioxidant; a sensitizer; a preservative; and a compound for adjusting the dielectric constant or electrical resistance of the resulting liquid crystal alignment film. Specific preferred examples of the crosslinkable compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, bisphenol A epoxy resins such as Epicoat 828 (manufactured by Mitsubishi Chemical Corporation), and Epicoat 807. (manufactured by Mitsubishi Chemical Corporation) and other bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins such as YX-8000 (manufactured by Mitsubishi Chemical Corporation), biphenyl skeleton-containing epoxy resins such as YX6954BH30 (manufactured by Mitsubishi Chemical Corporation), phenol novolac type epoxy resins such as EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.), (o, m, p-) cresol novolac type epoxy resins such as EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.), triglycidyl isocyanurate such as TEPIC (manufactured by Nissan Chemical Industries, Ltd.), alicyclic epoxy resins such as CELLOXIDE 2021P (manufactured by Daicel Corporation), N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,compounds containing a tertiary nitrogen atom, such as N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, and compounds having two or more oxiranyl groups, such as tetrakis(glycidyloxymethyl)methane; compounds having two or more oxetanyl groups, such as those described in paragraphs

[0170] to

[0175] of WO 2011 / 132751; Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (hereinafter compounds having a blocked isocyanate group such as Takenate B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, and B-882N (all manufactured by Mitsui Chemicals); compounds having an oxazoline group such as 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), 2,2'-bis(5-methyl-2-oxazoline), 1,2,4-tris(2-oxazolinyl)-benzene, and Epocross (manufactured by Nippon Shokubai); Compounds having a cyclocarbonate group as described in paragraphs

[0025] to

[0030] and

[0032] ; compounds having a hydroxy group or an alkoxy group such as N,N,N',N'-tetrakis(2-hydroxyethyl)adipamide, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxyphenyl)propane, and 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane; glycerin mono(meth)acrylamide, Examples of the compounds include acrylate, glycerin di(meth)acrylate (1,2-, 1,3-mixture), glycerin tris(meth)acrylate, glycerin 1,3-diglycerolate di(meth)acrylate, pentaerythritol tri(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate, and hexaethylene glycol mono(meth)acrylate.

[0058] The content of the crosslinkable compound is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, based on 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0059] Examples of the compound for adjusting the dielectric constant or electrical resistance include monoamines having a nitrogen atom-containing aromatic heterocycle such as 3-picolylamine. The content of the monoamine having a nitrogen atom-containing aromatic heterocycle is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0060] Specific preferred examples of the functional silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycidoxypropylmethyldimethoxysilane. , 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris[3-(trimethoxysilyl)propyl]isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, etc. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

[0061] The solid content concentration in the liquid crystal aligning agent (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) is appropriately selected in consideration of viscosity, volatility, etc., and is preferably 1 to 10 mass%.

[0062] The particularly preferred range of solid content varies depending on the method used to apply the liquid crystal alignment agent to the substrate. For example, when using a spin coating method, a solid content of 1.5 to 4.5 mass% is particularly preferred. When using a printing method, a solid content of 3 to 9 mass% is particularly preferred, thereby resulting in a solution viscosity of 12 to 50 mPa·s. When using an inkjet method, a solid content of 1 to 5 mass% is particularly preferred, thereby resulting in a solution viscosity of 3 to 15 mPa·s. The temperature during preparation of the liquid crystal alignment agent is preferably 10 to 50°C, more preferably 20 to 30°C. <Liquid Crystal Alignment Film / Liquid Crystal Display Element> A liquid crystal alignment film can be produced by using the liquid crystal alignment agent. The liquid crystal display element of the present invention comprises the liquid crystal alignment film. The operation mode of the liquid crystal display element according to the present invention is not particularly limited, and it can be applied to various operation modes, such as TN mode, STN (Super Twisted Nematic) mode, vertical alignment mode (including VA-MVA mode, VA-PVA mode, etc.), IPS mode, FFS mode, optically compensated bend mode (OCB mode), etc. The liquid crystal alignment film of the present invention is a liquid crystal alignment film suitable for liquid crystal display elements of a horizontal alignment mode, such as IPS mode or FFS mode. The liquid crystal display element of the present invention can be produced, for example, by a method including the following steps (1) to (3), a method including steps (1) to (4), a method including steps (1) to (3), (3b) and (4), a method including steps (1) to (3), (3a), (3b) and (4), a method including steps (1) to (2) and (4), a method including steps (1) to (3), (4) and (5), or a method including steps (1) to (3), (4) and (6). <Step (1): Step of applying a liquid crystal aligning agent to at least one of the first substrate and the second substrate> Step (1) is a step of applying the liquid crystal aligning agent of the present invention onto a substrate. Specific examples of step (1) are as follows.

[0063] The liquid crystal aligning agent of the present invention is applied to one side of a substrate having a patterned transparent conductive film by an appropriate application method, such as a roll coater method, a spin coat method, a printing method, or an inkjet method. The substrate is not particularly limited as long as it is highly transparent. In addition to glass substrates and silicon nitride substrates, plastic substrates such as acrylic substrates and polycarbonate substrates can also be used. In addition, in reflective liquid crystal display devices, an opaque material such as a silicon wafer can be used for only one substrate. In this case, a light-reflecting material such as aluminum can also be used for the electrode. Furthermore, when manufacturing an IPS or FFS liquid crystal display device, a substrate having an electrode made of a comb-shaped patterned transparent conductive film or metal film and an opposing substrate having no electrode are used. The transparent conductive film can be formed by a known method using, for example, indium tin oxide (ITO), indium zinc oxide (IZO), or a mixture thereof.

[0064] Examples of methods for applying the liquid crystal aligning agent to a substrate and forming a film include screen printing, offset printing, flexographic printing, an inkjet method, and a spray method. Among these, the application and film formation method using the inkjet method is preferably used. <Step (2): Step of baking the applied liquid crystal aligning agent> Step (2) is a step of baking the liquid crystal aligning agent applied to the substrate to form a film. Specific examples of step (2) are as follows.

[0065] After applying the liquid crystal aligning agent to the substrate in step (1), the solvent can be evaporated or the polyamic acid or polyamic acid ester can be thermally imidized using a heating means such as a hot plate, a heat circulation oven, or an IR (infrared) oven. The drying and baking steps after applying the liquid crystal aligning agent of the present invention can be performed at any temperature and for any time, and may be performed multiple times. The temperature in the baking step is preferably 30°C or higher and 200°C or lower. The temperature at which the solvent in the liquid crystal aligning agent is reduced can be, for example, 40 to 150°C. To shorten the process, the baking step may be performed at 40 to 120°C. The baking time is not particularly limited, but may be 1 to 10 minutes or 1 to 5 minutes. When thermally imidizing the polyamic acid or polyamic acid ester, a baking step at a temperature of 150°C or higher and 200°C or lower (hereinafter also referred to as the main baking step) may be added after the above step. The main firing step may be a step of firing at a temperature range of 160 to 200° C. or 160 to 190° C. The firing time is not particularly limited, but may be 5 to 40 minutes or 5 to 30 minutes. Note that the step (3b) may be carried out after the step (3) described below, without carrying out the main firing step.

[0066] If the film-like material after baking is too thin, the reliability of the liquid crystal display device may decrease, so the film thickness is preferably 5 to 300 nm, more preferably 10 to 200 nm.

[0067] <Step (3): Alignment Treatment of the Film Obtained in Step (2)> Step (3) is a step of, in some cases, aligning the film obtained in Step (2). That is, in horizontal alignment type liquid crystal display devices such as IPS or FFS modes, the coating film is subjected to an alignment ability imparting treatment. On the other hand, in vertical alignment type liquid crystal display devices such as VA or PSA modes, the formed coating film can be used as a liquid crystal alignment film as is, but the coating film may also be subjected to an alignment ability imparting treatment. Alignment treatment methods for liquid crystal alignment films include rubbing treatment and photo-alignment treatment, and more preferably photo-alignment treatment. Photo-alignment treatment methods include irradiating the surface of the film with radiation (more preferably polarized radiation) to impart liquid crystal alignment (also referred to as liquid crystal alignment ability). The radiation can be ultraviolet light or visible light having a wavelength of 100 to 800 nm. Among these, ultraviolet light having a wavelength of 100 to 400 nm is preferred, more preferably 200 to 400 nm. The rubbing treatment may involve rubbing the coating film in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton.

[0068] In the photo-alignment treatment method, when the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, the radiation may be irradiated from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When irradiating with unpolarized radiation, the irradiation direction is preferably oblique.

[0069] The radiation dose is 1 to 10,000 mJ / cm ２ is preferred, and 100 to 1000 mJ / cm ２ More preferably, 100 to 500 mJ / cm ２ is more preferred.

[0070] When radiation is irradiated in the photo-alignment treatment, in order to improve the liquid crystal alignment, the substrate having the film-like material may be irradiated while being heated at, for example, 50 to 200° C. The liquid crystal alignment film prepared in this manner can stably align liquid crystal molecules in a certain direction.

[0071] The liquid crystal alignment film obtained by the above method may further be subjected to a step of contact treatment using a solvent (hereinafter also referred to as step (3a)). The solvent used in the contact treatment in step (3a) is not particularly limited as long as it is a solvent that dissolves the decomposition products generated from the film-like material by irradiation with radiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 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 these, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred from the viewpoints of versatility and solvent safety. Water, 1-methoxy-2-propanol, or ethyl lactate are more preferred. The solvent may be one type or a combination of two or more types. The liquid crystal alignment film used in the liquid crystal display element of the present invention may be prepared by carrying out the following step (3b) after the above step (3). Step (3b) may be performed on a film treated in step (3a) as well as on a film oriented in step (3). <Step (3b): Heat Treatment Step> The radiation-irradiated coating film may be subjected to a heat treatment. The temperature for such heat treatment is preferably 50 to 200°C, more preferably 120 to 190°C, even more preferably 160 to 200°C, and even more preferably 160 to 190°C. The heat treatment time is preferably 1 to 30 minutes. <Step (4): Preparing a Liquid Crystal Cell by Arranging a Liquid Crystal Layer Between the First and Second Substrates Adjacent to the Aligned Film> Step (4) is a step of preparing a liquid crystal cell by arranging a liquid crystal layer between the first and second substrates adjacent to the aligned film. Note that the following example illustrates a case where a liquid crystal alignment film is formed on each of the first and second substrates. Specifically, the following two methods can be mentioned.

[0072] In the first method, two substrates are placed opposite each other with a gap (cell gap) between them so that their liquid crystal alignment films face each other, and then the peripheries of the two substrates are bonded together using a sealant. A liquid crystal composition is injected into the substrate surfaces and the cell gap defined by the sealant so that it comes into contact with the film surface, and the injection hole is then sealed.

[0073] The second method is called the ODF (One Drop Fill) method. For example, a UV-curable resin composition (hereinafter also referred to as a sealant) is applied to a predetermined location on one of two substrates on which a liquid crystal alignment film has been formed, and a liquid crystal composition is then dropped onto several predetermined locations on the liquid crystal alignment film surface. The other substrate is then attached so that the liquid crystal alignment film faces the other substrate, and the liquid crystal composition is spread over the entire surface of the substrate and brought into contact with the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. In either method, it is desirable to further heat the substrate to a temperature at which the liquid crystal composition is in an isotropic phase, and then slowly cool it to room temperature to remove flow alignment that occurs during liquid crystal filling.

[0074] When the coating films are subjected to rubbing treatment, the two substrates are placed opposite each other so that the rubbing directions of the coating films are at a predetermined angle, for example, perpendicular or anti-parallel to each other.

[0075] The sealing agent may be, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as spacers. The liquid crystal composition is not particularly limited, and any liquid crystal composition containing at least one liquid crystal compound (liquid crystal molecule) and having a positive or negative dielectric anisotropy may be used. Hereinafter, a liquid crystal composition having a positive dielectric anisotropy will be referred to as a positive liquid crystal, and a liquid crystal composition having a negative dielectric anisotropy will be referred to as a negative liquid crystal.

[0076] The liquid crystal composition may contain a liquid crystal compound having a fluorine atom, a hydroxy group, an amino group, a fluorine atom-containing group (e.g., a trifluoromethyl group), a cyano group, an alkyl group, an alkoxy group, an alkenyl group, an isothiocyanate group, a heterocycle, a cycloalkane, a cycloalkene, a steroid skeleton, a benzene ring, or a naphthalene ring, or may contain a compound having two or more rigid moieties (mesogenic skeletons) that exhibit liquid crystallinity within the molecule (e.g., a bimesogenic compound in which two rigid biphenyl structures or terphenyl structures are linked by an alkylene group).

[0077] The liquid crystal composition may be a liquid crystal composition exhibiting a nematic phase, a liquid crystal composition exhibiting a smectic phase, or a liquid crystal composition exhibiting a cholesteric phase.

[0078] The liquid crystal composition may further contain an additive from the viewpoint of improving the liquid crystal alignment property, such as a photopolymerizable monomer having a polymerizable group, an optically active compound (e.g., S-811 manufactured by Merck Ltd.), an antioxidant, an ultraviolet absorber, a dye, an antifoaming agent, a polymerization initiator, or a polymerization inhibitor.

[0079] Examples of the positive liquid crystal include ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081 manufactured by Merck.

[0080] Examples of negative liquid crystals include MLC-6608, MLC-6609, MLC-6610, and MLC-7026-100 manufactured by Merck.

[0081] Furthermore, an example of a liquid crystal containing a compound having a polymerizable group is MLC-3023 manufactured by Merck.

[0082] The liquid crystal aligning agent of the present invention is also preferably used for a liquid crystal display element (PSA type liquid crystal display element) manufactured through a step (hereinafter, this step may be referred to as step (5)) of having a liquid crystal layer between a pair of substrates provided with electrodes, and disposing a liquid crystal composition containing a polymerizable compound that is polymerized by at least one of active energy rays and heat between the pair of substrates, and polymerizing the polymerizable compound by at least one of irradiation with active energy rays and heating while applying a voltage between the electrodes.

[0083] The liquid crystal aligning agent of the present invention is also preferably used for a liquid crystal display element (SC-PVA type liquid crystal display element) which has a liquid crystal layer between a pair of substrates provided with electrodes, and is produced through a step of disposing a liquid crystal alignment film containing a polymerizable group that is polymerized by at least one of active energy rays and heat between the pair of substrates, and applying a voltage between the electrodes (hereinafter, this step is also referred to as step (6)).

[0084] A liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell as needed. Examples of the polarizing plate to be attached to the outer surface of the liquid crystal cell include a polarizing film called an "H film" made by stretching and aligning polyvinyl alcohol and absorbing iodine, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

[0085] An IPS substrate, which is a comb-tooth electrode substrate used in the IPS system, has a base material, a plurality of linear electrodes formed on the base material and arranged in a comb-tooth pattern, and a liquid crystal alignment film formed on the base material so as to cover the linear electrodes.

[0086] The FFS substrate, which is a comb-tooth electrode substrate used in the FFS method, has a base material, a surface electrode formed on the base material, an insulating film formed on the surface electrode, a plurality of linear electrodes formed on the insulating film and arranged in a comb-tooth shape, and a liquid crystal alignment film formed on the insulating film so as to cover the linear electrodes.

[0087] FIG. 1 is a schematic cross-sectional view showing an example of a lateral electric field type liquid crystal display element of the present invention, which is an example of an IPS type liquid crystal display element.

[0088] In the in-plane switching mode liquid crystal display element 1 illustrated in Fig. 1, liquid crystal 3 is sandwiched between a comb-tooth electrode substrate 2 having a liquid crystal alignment film 2c and a counter substrate 4 having a liquid crystal alignment film 4a. The comb-tooth electrode substrate 2 has a base material 2a, a plurality of linear electrodes 2b formed on the base material 2a and arranged in a comb-tooth pattern, and a liquid crystal alignment film 2c formed on the base material 2a so as to cover the linear electrodes 2b. The counter substrate 4 has a base material 4b and a liquid crystal alignment film 4a formed on the base material 4b. The liquid crystal alignment film 2c is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4c is also the liquid crystal alignment film of the present invention.

[0089] In this IPS mode liquid crystal display element 1, when a voltage is applied to the linear electrodes 2b, an electric field is generated between the linear electrodes 2b as indicated by electric force lines L.

[0090] FIG. 2 is a schematic cross-sectional view showing another example of the in-plane switching mode liquid crystal display element of the present invention, which is an example of an FFS mode liquid crystal display element.

[0091] In the in-plane switching mode liquid crystal display element 1 illustrated in Figure 2, liquid crystal 3 is sandwiched between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2h and a counter substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 has a base material 2d, a surface electrode 2e formed on the base material 2d, an insulating film 2f formed on the surface electrode 2e, a plurality of linear electrodes 2g formed on the insulating film 2f and arranged in a comb-like pattern, and a liquid crystal alignment film 2h formed on the insulating film 2f so as to cover the linear electrodes 2g. The counter substrate 4 has a base material 4b and a liquid crystal alignment film 4a formed on the base material 4b. The liquid crystal alignment film 2h is, for example, a liquid crystal alignment film of the present invention. The liquid crystal alignment film 4a is also a liquid crystal alignment film of the present invention.

[0092] In this IPS mode liquid crystal display element 1, when a voltage is applied to the surface electrodes 2 e and the linear electrodes 2 g, an electric field is generated between the surface electrodes 2 e and the linear electrodes 2 g, as indicated by the electric field lines L. The liquid crystal alignment film of the present invention can be used for a variety of purposes in addition to the above-mentioned applications, such as a liquid crystal alignment film for a retardation film, a liquid crystal alignment film for a scanning antenna or a liquid crystal array antenna, or a liquid crystal alignment film for a transmissive / scattering liquid crystal dimming element. Furthermore, the film can also be used for applications other than liquid crystal alignment films, such as a protective film (e.g., a protective film for a color filter), a spacer film, an interlayer insulating film, an antireflection film, a wiring covering film, an antistatic film, and a motor insulating film (a gate insulating film for a flexible display).

[0093] The liquid crystal display element of the present invention can be effectively applied to various devices, and can be used in various display devices such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays.

[0094] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The abbreviations of the compounds used and the methods for measuring the physical properties are as follows. (Organic solvents) DMF: N,N-dimethylformamide THF: tetrahydrofuran NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: ethylene glycol monobutyl ether (Tetracarboxylic acid dianhydrides) CA-1 to CA-2: Compounds represented by the following formulas (CA-1) to (CA-2), respectively

[0095]

[0096] (Diamine) DA-1 to DA-9: Compounds represented by the following formulas (DA-1) to (DA-9), respectively

[0097]

[0098] Of the above diamines, DA-2 and DA-8 fall within the scope of specific diamine (1). DA-3 and DA-7 fall within the scope of specific diamine (2). DA-6 falls within the scope of specific diamine (3). <Viscosity Measurement> Measurement was performed at 25°C using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL and a cone rotor TE-1 (1°34', R24). <Imidization Ratio Measurement> 20 mg of polyimide powder was placed in an NMR sample tube (NMR Sampling Tube Standard, φ5 (manufactured by Kusano Scientific Co., Ltd.)), and 1.0 mL of deuterated dimethyl sulfoxide (a mixture of [D6]-DMSO and 0.05% tetramethylsilane (TMS)) was added, followed by ultrasonication to completely dissolve the mixture. This solution was subjected to 500 MHz proton NMR measurement using a Fourier transform superconducting nuclear magnetic resonance (FT-NMR) "AVANCE III" (manufactured by BRUKER).

[0099] The (chemical) imidization rate was determined by the following formula, using a proton derived from a structure that remains unchanged before and after imidization as a reference proton, and the peak integrated value of this proton and the peak integrated value of a proton derived from the NH group of the amic acid that appears around 9.5 to 10.0 ppm: In the formula, x represents the peak integrated value of the proton derived from the NH group of the amic acid, y represents the peak integrated value of the reference proton, and α represents the ratio of the number of reference protons to one proton of the NH group of the amic acid in the case of polyamic acid (with an imidization rate of 0%).

[0100] Imidization rate (%)=(1−α·x / y)×100 [Synthesis of Monomer] DA-7 was synthesized by the following method.

[0101] The product described in Monomer Synthesis Example 1 below is １ The product was identified by H-NMR analysis (analysis conditions are as follows).

[0102] Apparatus: Fourier transform superconducting nuclear magnetic resonance spectrometer (FT-NMR) "AVANCE III" (manufactured by BRUKER) 500 MHz.

[0103] Solvent: deuterated dimethyl sulfoxide (DMSO-d ６, standard substance: tetramethylsilane) (Monomer Synthesis Example 1; Synthesis of DA-7) DA-7 was synthesized according to the route shown below.

[0104]

[0105] Under a nitrogen atmosphere, 2-(4-nitrophenoxy)ethyl methanesulfonate (19.6 g, 75.0 mmol), 4-nitrometacresol (11.5 g, 75.0 mmol), potassium carbonate (25.9 g, 187 mmol), and DMF (293 g) were added to a 500 mL four-neck flask and stirred at 100 °C for 3 hours to carry out the reaction. After the reaction, the mixture was cooled to 25 °C, 600 g of water was added, and the precipitated solid was filtered off. The cake was washed three times with water (200 g) and then with methanol (200 g), and the resulting solid was filtered off and dried to obtain DA-7-1 (22.9 g, 71.9 mmol, yield 96%, white solid).

[0106]

[0107] Under a nitrogen atmosphere, DA-7-1 (22.9 g, 71.9 mmol) obtained above, THF (457 g), and carbon-supported palladium (5% Pd carbon powder (50% water content) K type, manufactured by N.E. Chemcat Corporation, 2.28 g) were added to a 500 mL four-neck flask, and after replacing the atmosphere with hydrogen, the reaction was carried out at normal pressure and room temperature (25°C). After completion of the reaction, the carbon-supported palladium was removed by filtration, and the obtained filtrate was concentrated. Isopropyl alcohol (160 g) was added to the obtained crude product, and the crystals were filtered off and dried to obtain DA-7 (15.5 g, 59.8 mmol, yield 83%, white solid). １ The results of H-NMR confirmed that this solid was DA-7. １ H-NMR (500MHz, DMSO-d ６: δ (ppm) = 6.67 (d, 2H), 6.60 (s, 1H), 6.53-6.49 (m, 4H), 4.06 (s, 2H), 4.37 (s, 2H), 4.07 (s, 4H), 2.02 (s, 3H). [Synthesis of Polymer] <Synthesis Example 1> DA-1 (1.22 g, 5.00 mmol), DA-2 (1.15 g, 5.00 mmol), DA-3 (1.36 g, 5.00 mmol), DA-4 (1.49 g, 5.00 mmol), DA-5 (1.99 g, 5.00 mmol) and NMP (73.0 g) were placed in a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and the mixture was stirred at room temperature while supplying nitrogen to dissolve the mixture. Thereafter, CA-1 (5.38 g, 24.0 mmol) and NMP (19.4 g) were added under ice cooling, and the mixture was stirred at 40° C. for 12 hours to obtain a solution of polyamic acid (PAA-1) with a solid content of 12% by mass (viscosity: 382 mPa s).

[0108] The polyamic acid solution (60.0 g) obtained above was weighed into a 100 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and NMP (20.0 g), acetic anhydride (4.37 g), and pyridine (1.13 g) were added. The mixture was stirred at room temperature for 30 minutes, and then reacted at 65°C for 4.17 hours. This reaction solution was poured into methanol (342 g), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 80°C to obtain a polyimide powder. The imidization rate of this polyimide powder was 92%.

[0109] To the obtained polyimide powder (6.00 g), NMP was added so that the solids concentration was 12% by mass, and the mixture was stirred at 60° C. for 12 hours to dissolve the polyimide (PI-1) in a solution. Synthesis Example 2 To a 500 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (12.2 g, 50.0 mmol), DA-2 (11.5 g, 50.0 mmol), DA-3 (13.6 g, 50.0 mmol), DA-4 (14.2 g, 47.6 mmol), DA-6 (11.9 g, 50.0 mmol), and NMP (648 g) were added, and the mixture was stirred at room temperature while supplying nitrogen to dissolve the polyimide. Thereafter, CA-1 (53.8 g, 239 mmol) and NMP (216 g) were added under ice cooling, and the mixture was stirred at 40° C. for 12 hours to obtain a solution of polyamic acid (PAA-2) with a solid content of 12 mass % (viscosity: 414 mPa s).

[0110] The polyamic acid solution (450 g) obtained above was weighed into a 1 L four-neck flask equipped with a stirrer and a nitrogen inlet tube, and NMP was added to a solids concentration of 9 mass %, followed by acetic anhydride (34.9 g) and pyridine (9.02 g). The mixture was stirred at room temperature for 30 minutes and then reacted at 65°C for 4.17 hours. This reaction solution was poured into methanol (2576 g), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 80°C to obtain a polyimide powder. The imidization rate of this polyimide powder was 93%.

[0111] To the obtained polyimide powder (48.0 g), NMP was added so that the solids concentration was 12 mass%, and the mixture was stirred at 60° C. for 12 hours to dissolve the polyimide (PI-2) in a solution. Synthesis Example 3 To a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (1.22 g, 5.00 mmol), DA-2 (1.15 g, 5.00 mmol), DA-7 (1.29 g, 5.00 mmol), DA-4 (1.49 g, 5.00 mmol), DA-6 (1.19 g, 5.00 mmol), and NMP (64.1 g) were added, and the mixture was stirred at room temperature while supplying nitrogen to dissolve the polyimide. Thereafter, CA-1 (5.38 g, 24.0 mmol) and NMP (21.8 g) were added under ice cooling, and the mixture was stirred at 40° C. for 12 hours to obtain a solution of polyamic acid (PAA-3) with a solid content of 12 mass % (viscosity: 403 mPa s).

[0112] The polyamic acid solution (35.0 g) obtained above was weighed into a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and NMP was added to a solids concentration of 9 mass %, followed by acetic anhydride (2.74 g) and pyridine (0.710 g). The mixture was stirred at room temperature for 30 minutes and then reacted at 65°C for 3.17 hours. This reaction solution was poured into methanol (200 g), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 80°C to obtain a polyimide powder. The imidization rate of this polyimide powder was 91%.

[0113] To the obtained polyimide powder (3.60 g), NMP was added so that the solids concentration was 12 mass%, and the mixture was stirred at 60° C. for 12 hours to dissolve the polyimide (PI-3) in a solution. Synthesis Example 4 To a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (1.22 g, 5.00 mmol), DA-8 (1.29 g, 5.00 mmol), DA-3 (1.36 g, 5.00 mmol), DA-4 (1.49 g, 5.00 mmol), DA-6 (1.19 g, 5.00 mmol), and NMP (66.3 g) were added, and the mixture was stirred at room temperature while supplying nitrogen to dissolve the polyimide. Thereafter, CA-1 (5.38 g, 24.0 mmol) and NMP (21.3 g) were added under ice cooling, and the mixture was stirred at 40° C. for 12 hours to obtain a solution of polyamic acid (PAA-4) with a solid content of 12% by mass (viscosity: 418 mPa s).

[0114] The polyamic acid solution (35.0 g) obtained above was weighed into a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and NMP was added to a solids concentration of 9 mass %, followed by acetic anhydride (2.68 g) and pyridine (0.690 g). The mixture was stirred at room temperature for 30 minutes and then reacted at 65°C for 4.17 hours. This reaction solution was poured into methanol (200 g), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 80°C to obtain a polyimide powder. The imidization rate of this polyimide powder was 93%.

[0115] To the obtained polyimide powder (3.60 g), NMP was added so that the solids concentration was 12 mass%, and the mixture was stirred at 60° C. for 12 hours to dissolve the polyimide (PI-4), obtaining a solution of polyimide (PI-4). Synthesis Example 5 To a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (1.22 g, 5.00 mmol), DA-8 (1.29 g, 5.00 mmol), DA-7 (1.29 g, 5.00 mmol), DA-4 (1.49 g, 5.00 mmol), DA-6 (1.19 g, 5.00 mmol), and NMP (65.6 g) were added, and the mixture was stirred at room temperature while supplying nitrogen to dissolve the polyimide. Thereafter, CA-1 (5.42 g, 24.2 mmol) and NMP (21.7 g) were added under ice cooling, and the mixture was stirred at 40° C. for 12 hours to obtain a solution of polyamic acid (PAA-5) with a solid content of 12 mass % (viscosity: 372 mPa s).

[0116] The polyamic acid solution (60.0 g) obtained above was weighed into a 100 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and NMP was added to a solids concentration of 9 mass %, followed by acetic anhydride (4.63 g) and pyridine (1.20 g). The mixture was stirred at room temperature for 30 minutes and then reacted at 65°C for 4.17 hours. This reaction solution was poured into methanol (343 g), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 80°C to obtain a polyimide powder. The imidization rate of this polyimide powder was 93%.

[0117] To the obtained polyimide powder (6.00 g), NMP was added so that the solid content concentration was 12% by mass, and the mixture was stirred at 60° C. for 12 hours to dissolve the polyimide (PI-5). Synthesis Example 6 DA-4 (3.10 g, 10.4 mmol), DA-9 (8.28 g, 41.6 mmol), CA-2 (14.7 g, 49.9 mmol), and NMP (191 g) were added to a 200 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and the mixture was stirred at 70° C. for 15 hours to obtain a solution of polyamic acid (PAA-6) (viscosity: 461 mPa s) having a solid content concentration of 12% by mass. Synthesis Example 7 DA-4 (4.12 g, 13.8 mmol), DA-9 (1.83 g, 9.20 mmol), CA-2 (6.39 g, 21.7 mmol), and NMP (90.5 g) were added to a 100 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and the mixture was stirred at 70° C. for 15 hours to obtain a solution of polyamic acid (PAA-7) with a solids concentration of 12 mass% (viscosity: 408 mPa s).

[0118] The specifications of the polyamic acids obtained in the above synthesis examples are shown in Table 1. In Table 1, the parenthesized numbers for the diamine components represent the amount (parts by mole) of each compound used relative to 100 parts by mole of the total amount of the diamine components used in each polymerization step. The parenthesized numbers for the tetracarboxylic acid components represent the amount (parts by mole) of each compound used relative to 100 parts by mole of the total amount of the tetracarboxylic acid components used in each polymerization step. The parenthesized numbers for the organic solvents represent the amount (parts by mass) of each compound used relative to 100 parts by mass of the total amount of the organic solvents used in each polymerization step.

[0119]

[0120] [Preparation of Liquid Crystal Alignment Agent] Comparative Example 1: The solution of polyimide (PI-1) obtained in Synthesis Example 1, NMP, GBL, and BCS were added to a sample tube containing a stirrer and stirred at 25°C for 30 minutes to obtain a liquid crystal alignment agent (AL-R1) with a polymer solids to solvent mass ratio (polymer solids:NMP:GBL:BCS) of 6:44:30:20. Comparative Example 2 and Examples 1 to 8: Liquid crystal alignment agents (AL-R2) and (AL-1) to (AL-8) were obtained by the same procedure as in Comparative Example 1, except that the type of polymer solution used was changed as shown in Table 2. In Table 2, the numbers in parentheses indicate the blending ratio (parts by mass) of each polymer component relative to 100 parts by mass of the total polymer components used in the preparation of the liquid crystal alignment agent. For organic solvents, the blending ratio (parts by mass) of each organic solvent relative to 100 parts by mass of the liquid crystal alignment agent was obtained.

[0121]

[0122] [Fabrication of FFS Drive Liquid Crystal Cell] A liquid crystal cell having the structure of an FFS mode liquid crystal display element was fabricated.

[0123] First, a substrate with electrodes was prepared. The substrate was a rectangular glass substrate measuring 30 mm x 35 mm and 0.7 mm thick. A solid-patterned ITO electrode constituting a common electrode was formed on the substrate as the first layer. A SiN (silicon nitride) film formed by CVD (chemical vapor deposition) was formed on the first common electrode as the second layer. The second SiN film had a thickness of 300 nm, which served as an interlayer insulating film. A comb-shaped pixel electrode formed by patterning an ITO film as the third layer was placed on the second SiN film. Two pixels, a first pixel and a second pixel, were formed, each measuring 10 mm long and 5 mm wide. This electrode-equipped substrate had a structure in which the first common electrode and the third pixel electrode were insulated by the second SiN film.

[0124] The pixel electrode of the third layer had a comb-like shape with the central portion bent at an interior angle of 160° and multiple electrode lines, each 3 μm wide, arranged parallel to each other at intervals of 6 μm. One pixel was formed by multiple electrode lines and had a first region and a second region separated by a line connecting the bent portions.

[0125] Next, the liquid crystal alignment agent obtained above was filtered through a filter with a pore size of 1.0 μm, and then spin-coated onto the electrode-attached substrate (hereinafter referred to as the electrode substrate) and a glass substrate (hereinafter referred to as the counter substrate) having 4 μm-high columnar spacers and an ITO film formed on the backside. This was dried on a hot plate at 80°C for 2 minutes to form a coating film with a thickness of 100 nm. The coating surface was irradiated with 254 nm polarized UV light through a 240 nm low-cut filter and a polarizer at the dose listed in Table 3 (optimal dose for each liquid crystal alignment agent), and then baked in an IR oven at 180°C for 30 minutes to perform an alignment treatment, thereby obtaining a substrate with a liquid crystal alignment film. The liquid crystal alignment film formed on the electrode substrate was aligned so that the direction dividing the interior angle of the pixel bend was perpendicular to the alignment direction of the liquid crystal. The alignment film formed on the counter substrate was aligned so that the alignment direction of the liquid crystal on the electrode substrate was aligned with the alignment direction of the liquid crystal on the counter substrate when the liquid crystal cell was fabricated. The two substrates were combined into a set, and a sealant (Mitsui Chemicals XN-1500T) was printed on one substrate using a dispenser. Another substrate was then attached to the other substrate, with the alignment direction of each liquid crystal alignment film facing each other at 0°. The attached substrates were then pressed together and heated in a hot air circulating oven at 150°C for 60 minutes to cure the sealant, producing an empty cell. Positive liquid crystal MLC-3019 (Merck) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. The resulting liquid crystal cell was then heated at 120°C for 1 hour and left overnight at 23°C before use. [Evaluation of In-Plane Uniformity of Contrast] In-plane uniformity of contrast was measured using an AxoStep system manufactured by AXOMETRICS. The liquid crystal cell prepared above was placed on a measurement stage, and the distribution of circular retardance within the pixel plane was measured with no voltage applied, and 3σ, which is three times the standard deviation σ, was calculated. The smaller the 3σ value, the better the in-plane uniformity. The results are shown in Table 3. [Evaluation of liquid crystal alignment stability] This evaluation evaluates image retention (also known as AC image retention) that occurs when the alignment performance of the liquid crystal alignment film deteriorates during long-term AC driving.

[0126] The FFS drive liquid crystal cell produced above was used in conjunction with a high-brightness backlight (light source: LED, brightness: 20,000 cd / m) with a surface temperature of 50°C. ２ ) and an AC voltage of ±4.3 V at a frequency of 30 Hz was applied for 168 hours. The pixel electrode and common electrode of the liquid crystal cell were then shorted and left at room temperature (23°C) for one day. For the liquid crystal cells subjected to the above treatment, the deviation between the alignment direction of the liquid crystal in the first region of the pixel and the alignment direction of the liquid crystal in the second region of the pixel when no voltage was applied was calculated as an angle. Specifically, the liquid crystal cell was placed between two polarizing plates arranged so that their polarization axes were perpendicular to each other, and the backlight was turned on. The liquid crystal cell was then adjusted to minimize the transmitted light intensity in the first region of the first pixel. The rotation angle Δ required to rotate the liquid crystal cell to minimize the transmitted light intensity in the second region of the first pixel was then calculated. The first and second regions of the second pixel were similarly compared, and the same angle Δ was calculated. The average of the angles Δ for the first and second pixels was then calculated as the rotation angle Δ of the liquid crystal cell. The smaller the rotation angle Δ, the better the liquid crystal alignment stability. The results are shown in Table 3.

[0127]

[0128] As shown in Table 3, the liquid crystal alignment films obtained from the liquid crystal alignment agents using specific diamine (1), specific diamine (2), and specific diamine (3) had better in-plane contrast uniformity and liquid crystal alignment stability than the liquid crystal alignment film obtained from the liquid crystal alignment agent not using specific diamine (3).

[0129] By using the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal alignment film that can be applied to a low-temperature baking process and has a high level of suppression of AC afterimages and good in-plane uniformity of contrast, even when the amount of light irradiation during alignment treatment by a photoalignment method is low. Therefore, it is expected to be used in liquid crystal display elements that require high display quality, particularly liquid crystal display elements using an IPS drive system or an FFS drive system. These elements are also useful in liquid crystal displays for display purposes, dimming windows that control light transmission and blocking, optical shutters, etc.

[0130] 1: In-plane switching liquid crystal display element, 2: comb-tooth electrode substrate, 2a: substrate, 2b: linear electrode, 2c: liquid crystal alignment film, 2d: substrate, 2e: plane electrode, 2f: insulating film, 2g: linear electrode, 2h: liquid crystal alignment film, 3: liquid crystal, 4: opposing substrate, 4a: liquid crystal alignment film, 4b: substrate, L: electric field line

[0131] The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2023-175565 filed on October 10, 2023 are hereby incorporated by reference as the disclosure of the present invention.

Claims

1. A liquid crystal aligning agent comprising at least one polymer (P) selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid component containing at least one selected from the group consisting of tetracarboxylic dianhydrides represented by the following formula (1) and derivatives thereof, and a diamine component containing a diamine represented by the following formula (2-1), a diamine represented by the following formula (2-2), and a diamine represented by the following formula (2-3), and a polyimide which is an imidized product of the polyimide precursor. (In formula (1), R １ ~R ４ 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; R １ ~R ４ At least one of represents a group other than a hydrogen atom as defined above. In formula (2-1), n1 is an integer of 1 or 3. The benzene ring bonded to the amino group is unsubstituted, or one or more hydrogen atoms on the benzene ring are substituted with a monovalent group. However, when n1 is 1, the monovalent group is a monovalent group other than a methyl group or a fluorine atom. Z １ each independently represents a hydrogen atom, or an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted alkenyl group having 2 to 6 carbon atoms, or an optionally substituted aralkyl group having 7 to 13 carbon atoms. ２１ , R ２２ each independently represents a hydrogen atom, a methyl group, or a fluorine atom; R ２１ , R ２２ At least one of Z represents a methyl group or a fluorine atom. ２ each independently represents a hydrogen atom, or an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted alkenyl group having 2 to 6 carbon atoms, or an optionally substituted aralkyl group having 7 to 13 carbon atoms. n2 is an integer of 1 or 2. Ｎ represents a monovalent organic group having a thermally detachable group. ３ each independently represents a hydrogen atom, or an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted alkenyl group having 2 to 6 carbon atoms, or an optionally substituted aralkyl group having 7 to 13 carbon atoms.

2. The liquid crystal aligning agent according to claim 1, wherein the content of the diamine represented by the formula (2-1), the content of the diamine represented by the formula (2-2), and the content of the diamine represented by the formula (2-3) are each 5 mol% or more relative to 1 mol of the diamine component used in the production of the polymer (P).

3. The liquid crystal aligning agent according to claim 1, wherein the diamine represented by the formula (2-1) is bis(4-aminophenoxy)methane or 1,3-bis(4-aminophenoxy)propane.

4. The liquid crystal aligning agent according to claim 1, wherein the diamine represented by the formula (2-2) is bis(4-amino-2-methylphenoxy)methane, bis(4-amino-3-methylphenoxy)methane, bis(4-amino-2-fluorophenoxy)methane, bis(4-amino-3-fluorophenoxy)methane, 1,2-bis(4-amino-2-methylphenoxy)ethane, 1,2-bis(4-amino-3-methylphenoxy)ethane, 1,2-bis(4-amino-2-fluorophenoxy)ethane, 1,2-bis(4-amino-3-fluorophenoxy)ethane, or a diamine represented by any one of the following formulas (2-2-1) to (2-2-4). (In the formula, n2 has the same definition as n2 in the above formula (2-2).) 5. R in the above formula (1) １ ~R ４ The liquid crystal aligning agent according to claim 1 , wherein at least two of the following groups represent a group other than a hydrogen atom in the definitions.

6. The liquid crystal aligning agent according to claim 1, wherein the content of the tetracarboxylic dianhydride represented by the formula (1) and its derivative is 10 mol % or more relative to 1 mol of the tetracarboxylic acid component used in the production of the polymer (P).

7. The diamine component further comprises a phenylenediamine, a diaminobiphenyl compound, or a compound represented by the following formula (d ＡＬ ) (excluding the diamine represented by the formula (2-1) and the diamine represented by the formula (2-2)), diamines having a diphenyl ether structure, diamines having a tetracarboxylic diimide structure, diamines having an amide bond, diamines having a urea bond, and diamines having a group "-N(D)-" (excluding the diamine represented by the formula (2-3)). The liquid crystal aligning agent according to claim 1, containing at least one other diamine selected from the group consisting of diamines having a diphenyl ether structure, diamines having a tetracarboxylic diimide structure, diamines having an amide bond, diamines having a urea bond, and diamines having a group "-N(D)-". (Ar １ , and Ar １’ each represents a benzene ring, a biphenyl structure, or a naphthalene ring, and one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring may be unsubstituted or substituted with a monovalent group. １ and L １’ each represents a single bond, -O-, -C(=O)-, or -O-C(=O)-. A is -CH ２ represents an alkylene group having 2 to 12 carbon atoms, or a divalent organic group in which at least one of -O-, -C(=O)-O-, and -O-C(=O)- is inserted between the carbon-carbon bonds of the alkylene group.

8. The liquid crystal aligning agent according to claim 6, wherein the total content of the diamine represented by the formula (2-1), the diamine represented by the formula (2-2), and the diamine represented by the formula (2-3) is 95 mol% or less relative to 1 mol of the diamine component used in the production of the polymer (P), and the content of the other diamines is 5 to 85 mol% relative to 1 mol of the diamine component used in the production of the polymer (P).

9. A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 8.

10. A liquid crystal display device comprising the liquid crystal alignment film of claim 9.

11. A method for manufacturing a liquid crystal display element, comprising the following steps (1) to (4): step (1): applying the liquid crystal alignment agent according to any one of claims 1 to 8 to at least one of a first substrate and a second substrate; step (2): baking the applied liquid crystal alignment agent to obtain a film; step (3): performing an alignment treatment on the film obtained in step (2); and step (4): arranging a liquid crystal layer between the first substrate and the second substrate so as to be adjacent to the alignment-treated film to prepare a liquid crystal cell.

12. The method for producing a liquid crystal display element according to claim 11, wherein the alignment treatment is a photoalignment treatment.

13. The method for producing a liquid crystal display element according to claim 12, further comprising a step (3b) of performing a heat treatment between the steps (3) and (4).

14. The method for producing a liquid crystal display element according to claim 13, wherein the temperature of the heat treatment in the step (3b) is 50 to 200° C.

15. The method for producing a liquid crystal display element according to claim 14, wherein the liquid crystal display element is an IPS-type or FFS-type liquid crystal display element.