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

Abstract

Provided is a liquid crystal alignment agent able to yield: a liquid crystal alignment film in which a generated charge can be lowered in a short time while the absolute value of accumulated charge is lowered; and a liquid crystal alignment film in which charge accumulation and flickering attributable to the light of a backlight is lowered.　This liquid crystal alignment agent contains at least one type of polymer (P) selected from the group consisting of: a polyimide precursor obtained using at least one type of tetracarboxylic acid component selected from the group consisting of tetracarboxylic acid dianhydrides represented by formula (1) and derivatives thereof and a diamine component represented by formula (2); and a polyimide that is an imidation product of said polyimide precursor. (Xa denotes a tetravalent organic group derived from an aromatic tetracarboxylic acid dianhydride or a derivative thereof. Y2 denotes a divalent organic group having 6-30 carbon atoms and containing one or more aromatic groups. Z2 moieties each independently denote an alkylene group having 1-6 carbon atoms. A2 moieties each independently denote an alkyl group having 1-6 carbon atoms. An arbitrary hydrogen atom in an aromatic group in Y2 may be substituted by a monovalent group.)

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 elements are widely used as display units for personal computers, mobile phones, smartphones, televisions, etc. Liquid crystal display elements include, for example, a liquid crystal layer sandwiched between an 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 liquid crystal alignment of liquid crystal molecules in the liquid crystal layer, and thin film transistors (TFTs) that switch electrical signals supplied to the pixel electrodes. Known methods for driving liquid crystal molecules include vertical electric field methods such as the TN (Twisted Nematic) method and the VA (Vertical Alignment) method, and horizontal electric field methods such as the IPS (In-Plane Switching) method and the FFS (Fringe Field Switching) method. The horizontal electric field method, in which electrodes are formed on only one side of the substrate and an electric field is applied parallel to the substrate, is known as a liquid crystal display element that has a wider viewing angle and is capable of high-quality display compared to the conventional vertical electric field method, in which voltage is applied to electrodes formed on the top and bottom substrates to drive the liquid crystal.

[0003] In IPS liquid crystal cells, static electricity easily accumulates within the liquid crystal cell, and the application of asymmetric positive and negative voltages during operation also accumulates charge within the liquid crystal cell. These accumulated charges affect the display by disrupting the liquid crystal alignment and causing afterimages, significantly reducing the display quality of the liquid crystal element. Furthermore, because charge accumulates when backlight light is irradiated onto the liquid crystal cell immediately after operation, afterimages occur even after a short period of operation, and problems such as flickering occur during operation.

[0004] Patent Document 1 discloses a liquid crystal aligning agent for use in a lateral electric field type liquid crystal cell, which contains a polymer obtained by polycondensation of an aromatic diamine having an alkylated terminal amino group and a specific alicyclic tetracarboxylic acid dianhydride.

[0005] JP 2019-101196 A

[0006] In recent high-brightness liquid crystal display devices, the brightness of the backlight has increased, and the visibility of afterimages due to accumulated charge has also increased. Therefore, a liquid crystal alignment film that can reduce the absolute value of accumulated charge while reducing the generated charge in a short period of time is required. In addition, there is an increased need for a liquid crystal alignment film that reduces charge accumulation and flicker caused by backlight light. As a result of the inventor's studies, it has become clear that when a polymer obtained by polycondensation of an aromatic diamine with alkylated terminal amino groups and an alicyclic tetracarboxylic dianhydride is used as a liquid crystal aligning agent, a product that fully satisfies the above-mentioned requirements cannot be obtained.

[0007] In view of the above circumstances, the object of the present invention is to provide a liquid crystal alignment film that can reduce the absolute value of accumulated charge while reducing the generated charge in a short period of time, and a liquid crystal alignment agent that can obtain a liquid crystal alignment film in which charge accumulation and flicker caused by backlight light are reduced.

[0008] The present inventors have conducted extensive research to achieve the above object, and have found that the use of a specific tetracarboxylic acid component and a specific diamine component is effective for achieving the above object. They have also found that a liquid crystal aligning agent having the following composition is optimal for achieving the above object, and have completed the present invention.

[0009] Thus, the present invention is based on the above findings and has the following gist: A liquid crystal aligning agent containing 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), and a polyimide which is an imidized product of the polyimide precursor: (X ａ represents a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride or a derivative thereof. ２ represents a divalent organic group having 6 to 30 carbon atoms and containing one or more aromatic groups. ２ each independently represents an alkylene group having 1 to 6 carbon atoms. ２ each independently represents an alkyl group having 1 to 6 carbon atoms. ２Any hydrogen atom in the aromatic group in may be replaced with a monovalent group.) Throughout this specification, examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, and * represents a bond.

[0010] By using the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal alignment film that can reduce the absolute value of accumulated charge while reducing generated charge in a short time, and a liquid crystal alignment film in which charge accumulation and flicker caused by backlight are reduced. The mechanism by which the above-mentioned effects of the present invention are obtained is not necessarily clear, but the following is thought to be one of the reasons. In the baking process of manufacturing a liquid crystal display element, polyamic acid, which is the main component of the liquid crystal aligning agent, undergoes a thermal imidization reaction. This is a reaction in which imide rings are formed by heating, and the lower the ratio (imidization rate), the higher the polarity becomes, making it easier to reduce charge. In the present invention, A of the above diamine (2) ２ It is believed that the presence of inhibits the ring-closing reaction, making it easier to reduce the charge even in normal firing.

[0011] 1 is a schematic cross-sectional view showing an example of a horizontal electric field liquid crystal display element of the present invention, and FIG. 2 is a schematic cross-sectional view showing another example of a horizontal electric field liquid crystal display element of the present invention.

[0012] <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 aromatic tetracarboxylic acid component (p) in the present invention), and a diamine component containing a diamine represented by the above formula (2) (also referred to as a specific diamine (p) in the present invention), and a polyimide which is an imidized product of the polyimide precursor. The polymer (P) may be one type or two or more types. Here, the polyimide precursor is a polymer that can be obtained by imidizing a polyamic acid, a polyamic acid ester, or the like to obtain a polyimide.

[0013] (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 a diamine component containing the specific diamine (p) and a 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.

[0014] X in the above formula (1) ａ represents a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride or a derivative thereof. The aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to an aromatic ring. However, it is not necessary for the aromatic ring structure to be composed solely of an aromatic ring structure, and it may also have a chain hydrocarbon structure or an alicyclic structure in part. X in the above formula (1) ａ is preferably a structure selected from the following formulae (Xa-1) and (Xa-2): (In formulas (Xa-1) to (Xa-2), j and k are integers of 0 or 1, and A １ and A ２ are each independently a single bond, —O—, —C(═O)—, —O—C(═O)—, a phenylene group, or —S(═O) ２ - or -NR-C(=O)- (R represents a hydrogen atom or a methyl group). ２ may be the same or different.)

[0015] Preferred specific examples of the above formulae (Xa-1) and (Xa-2) include the following formulae (Xa-3) to (Xa-18).

[0016] X ａ From the viewpoint of enhancing the liquid crystal alignment property, the above formulae (Xa-3) to (Xa-7) are more preferable, and the above formulae (Xa-3) to (Xa-6) are even more preferable.

[0017] The proportion of the specific aromatic tetracarboxylic acid component (p) used 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 polymer (P).

[0018] The tetracarboxylic acid component used in the production of the polymer (P) may contain a tetracarboxylic acid component other than the specific aromatic tetracarboxylic acid component (p) (hereinafter also referred to as "other tetracarboxylic acid component"). When the other tetracarboxylic acid component is used in combination with the specific aromatic tetracarboxylic acid component (p), the amount of the specific aromatic tetracarboxylic acid component (p) used is preferably 90 mol% or less, more preferably 80 mol% or less, based on 1 mol of the total tetracarboxylic acid components used in the polymer (P).

[0019] Examples of the other tetracarboxylic acid component include acyclic aliphatic tetracarboxylic acid dianhydrides, alicyclic tetracarboxylic acid dianhydrides, and derivatives thereof. The acyclic aliphatic tetracarboxylic acid dianhydrides are acid dianhydrides obtained by intramolecular dehydration of four carboxy groups bonded to a chain hydrocarbon structure. However, they do not necessarily have to be composed solely of a chain hydrocarbon structure, and may partially contain an alicyclic structure or an aromatic ring structure. The alicyclic tetracarboxylic acid dianhydrides are acid dianhydrides 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, they do not necessarily have to be composed solely of an alicyclic structure, and may partially contain a chain hydrocarbon structure or an aromatic ring structure. The acyclic aliphatic or alicyclic tetracarboxylic acid dianhydride or a derivative thereof is preferably a tetracarboxylic acid dianhydride having at least one partial structure selected from the group consisting of a cyclobutane ring structure, a cyclopentane ring structure, and a cyclohexane ring structure, from the viewpoint of enhancing the liquid crystal alignment property.

[0020] The other tetracarboxylic acid component is preferably a tetracarboxylic acid dianhydride represented by the following formula (t) or a derivative thereof.

[0021] X in formula (t) Ｔ is a structure selected from the following formulas (X1-1) to (X1-23).

[0022]

[0023]

[0024]

[0025] In formulae (X1-1) to (X1-4), R １ ~R ２１ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. １ ~R ２１ are each independently preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group.

[0026] Specific examples of formula (X1-1) include the following formulae (1-1) to (1-6): From the viewpoint of enhancing the liquid crystal alignment property, formulae (1-1) to (1-2) are particularly preferred.

[0027] From the viewpoint of enhancing the liquid crystal alignment property, the X Ｔ is preferably the above formula (X1-1) to (X1-10), or (X1-18) to (X1-23), more preferably the above formula (X1-1), (X1-5), (X1-7) to (X1-10), (X1-21), or (X1-23), and even more preferably the above formula (1-1), (1-2), (X1-5), (X1-7), (X1-8), or (X1-9).

[0028] (Specific diamine (p)) The specific diamine (p) of the present invention is a diamine represented by the above formula (2). The specific diamine (p) may be used singly or in combination of two or more. The amount of the specific diamine (p) used is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more, relative to 1 mol of the diamine component used in the production of the polymer (P).

[0029] Y in the above formula (2) ２ represents a divalent organic group having 6 to 30 carbon atoms and containing one or more aromatic groups. The aromatic group refers to an aromatic hydrocarbon group or an aromatic heterocyclic group, and includes a monocyclic group, a fused ring group, and a group in which a monocyclic or fused ring is linked. Examples of the aromatic ring structure in the aromatic group include a benzene ring, a naphthalene ring, and a biphenyl structure. Any hydrogen atom in the aromatic group may be replaced with a monovalent group. Examples of the monovalent group include a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkenyl group having 2 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, a carboxy group, a hydroxy group, an alkyloxycarbonyl group having 1 to 10 carbon atoms, a cyano group, and a nitro group. In addition, Y ２ Is Z ２ The polymer (P) is preferably bonded to Y through an atom constituting an aromatic ring, and more preferably bonded to Y through a carbon atom constituting an aromatic ring. ２ It is more preferable that the polymer (P) has an aromatic group in the main chain direction of the polymer (P). The main chain of the polymer refers to the part consisting of the longest chain of atoms in the polymer. ２ The phrase "having an aromatic group in the main chain direction of the polymer (P)" means that ２ The aromatic group contained in Y constitutes the main chain of the polymer (P). ２ However, when two or more aromatic groups are contained, the aromatic ring structures in the aromatic groups may be bonded to each other via a linking group. ２ -, -C(CH ３ ) ２-, -O-, -C(=O)-, -O-C(=O)-, -NR-C(=O)-, -NR- (R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a tert-butoxycarbonyl group), an alkylene group having 2 to 18 carbon atoms, or -CH of the alkylene group. ２ Part of - is -O-, -Si(CH ３ ) ２ and divalent organic groups substituted with -, -C(=O)-, -O-C(=O)-, -NR-C(=O)-, or -NR- (R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a tert-butoxycarbonyl group).

[0030] Y ２ From the viewpoint of enhancing the liquid crystal alignment property, it is preferable that the structure be represented by the following formula (3). (L is -CH ２ -, -O-, -C(=O)-, -N(R)- (wherein R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group), a cyclohexylene group, or an alkylene group having 2 to 18 carbon atoms. However, any -CH ２ - may be substituted with -O-, -O-C(=O)-, -C(=O)-, -N(R)- (wherein R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group), -N(R)-C(=O)- (wherein R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group), a cyclohexylene group, or a phenylene group. In addition, the hydrogen atom on the phenylene group may be substituted with a halogen atom, or an alkyl group or alkoxy group having 1 to 5 carbon atoms. R ３ represents a halogen atom, or an alkyl or alkoxy group having 1 to 5 carbon atoms, and any hydrogen atom in the alkyl or alkoxy group may be substituted with a halogen atom, and any hydrocarbon group may be substituted with an amino group protected with a tert-butoxycarbonyl group. Multiple a's are each independently an integer of 0 to 4, b is an integer of 1 or 2, and c is an integer of 0 to 1. R ３ When a plurality of a's are present, they may be the same or different.

[0031] More preferred specific examples of L include -O-, -O-C(=O)-, -C(=O)-, -N(R)- (R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group), -N(R)-C(=O)- (R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group), -N(R)-C(=O)-N(R)- (R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group; two Rs may be the same or different), -(CH ２ ) ｐ -, -O-(CH ２ ) ｐ -O-, -(CH ２ ) ｐ -OC(=O)-(CH ２ ) ｑ -, -(CH ２ ) ｐ -N(R)-(CH ２ ) ｑ -(R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group), -(CH ２ ) ｐ -N(R)-C(=O)-N(R)-(CH ２ ) ｑ -(R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group; the two R may be the same or different), -O-(CH ２ ) ｐ -O-(CH ２ ) ｑ -O-, -(CH ２ ) ｐ’ -OC(=O)-(CH ２ ) ｑ -C(=O)-O-(CH ２ ) ｒ’ -, -(CH ２ ) ｐ’ -C(=O)-O-(CH ２ ) ｑ -OC(=O)-(CH ２ ) ｒ’ -, -(CH ２ ) ｐ’ -OC(=O)-Q-C(=O)-O-(CH ２ ) ｑ’-(Q represents a phenylene group or a cyclohexylene group), -(CH ２ ) ｐ’ -C(=O)-O-Q-OC(=O)-(CH ２ ) ｑ’ - (Q represents a phenylene group or a cyclohexylene group). Here, p is an integer of 1 to 6, preferably an integer of 2 to 6. q is an integer of 1 to 6, more preferably an integer of 2 to 6, and even more preferably an integer of 2 to 4. p', q', and r' are integers of 0 to 6. In addition, 0≦p'+q' ≦10 is satisfied, and 2≦p'+q+r' ≦16 is satisfied.

[0032] Z ２ are each independently an alkylene group having 1 to 6 carbon atoms. From the viewpoint of improving the liquid crystal alignment property, a methylene group or an ethylene group is preferred. ２ is an alkyl group having 1 to 6 carbon atoms. ２ is preferably a methyl group or an ethyl group.

[0033] More preferred specific examples of the diamine represented by the above formula (2) include diamines represented by any of the following formulas (d2-1) to (d2-3).

[0034] The diamine component used in the production of the polymer (P) may contain a diamine other than the specific diamine (p) (hereinafter also referred to as "other diamine"). When other diamines are used in addition to the specific diamine (p), the amount of the specific diamine (p) used relative to 1 mole of the diamine component used in the production of the polymer (P) is preferably 90 mol% or less, more preferably 80 mol% or less.

[0035] Examples of other diamines include, but are not limited to, the following: The above other diamines may be used singly or in combination of two or more.

[0036] p-phenylenediamine, m-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 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, 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, 2,3'-diaminobiphenyl, 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, 1,11-bis(4-aminophenoxy)undecane, 1,11-bis(3-aminophenoxy) (iii) 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, 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine, 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, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene benzene, 1,4-bis(4-aminobenzyl)benzene, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene (hereinafter, these are also collectively referred to as first diamines).diamines having a photoalignment group such as 4,4'-diaminoazobenzene or diaminotolane; diamines having an amide bond such as 4,4'-diaminobenzanilide; diamines having a urea bond such as 1,3-bis(4-aminophenyl)urea, 1,3-bis(4-aminobenzyl)urea, 1,3-bis(4-aminophenethyl)urea; 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine azine, 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-3,5-diaminobenzamide, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-4 heterocycle-containing diamines such as N,N'-methyl-2-oxazolyl]-benzeneamine, or diamines represented by the following formulae (z-1) to (z-13), or 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), typified by diamines having a diphenylamine structure such as 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-benzenediamine (provided that the molecule does not have an amino group bonded to a protecting group that is cleaved by heating and replaced with a hydrogen atom; and the specific diamine (p) is excluded).), 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 diamines having a carboxy group such as 4-(2-(methylamino) 4-(2-aminoethyl)aniline, 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 a photopolymerizable group at the terminal such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline; cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, Diamines having a steroid skeleton such as cholestanyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate, lanostannyl 3,5-diaminobenzoate, and 3,6-bis(4-aminobenzoyloxy)cholestane; diamines represented by the following formulae (V-1) to (V-2); and groups "-N(D)-" (D represents a protecting group which is eliminated by heating and replaced with a hydrogen atom, preferably a tert-butoxycarbonyl group) represented by the following formulae (5-1) to (5-11).diamines having a siloxane bond such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and 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.

[0037] In the formula (V-1), m and n each independently represent an integer of 0 to 3, and satisfy the relationship 1≦m+n≦4. j represents 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—. １ represents 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. (Boc represents a tert-butoxycarbonyl group.)

[0038] Examples of the nitrogen atom-containing heterocycle that the diamine having a 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.

[0039] From the viewpoint of enhancing liquid crystal alignment properties, the other diamine may be a diamine selected from the group consisting of the first diamine, a diamine having an amide bond, a diamine having a urea bond, a diamine having a group "-N(D)-", a diamine having a specific nitrogen atom-containing structure, and a diamine having a carboxy group.

[0040] (Liquid Crystal Aligning 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.

[0041] 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 aromatic 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 the specific diamine (p) 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.

[0042] Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, and SMA3000 (manufactured by Cray Valley Corporation), and GSM301 (manufactured by Gifu Ceramics Manufacturing Co., Ltd.), while a specific example of poly(isobutylene-maleic anhydride) copolymers includes ISOBAM-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). Among these, polymer (B) is more preferred from the viewpoint of reducing residual DC-derived afterimages. The above other polymers may be used alone or in combination of two or more. The content ratio 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.

[0043] (Polymer (B)) Specific examples of the tetracarboxylic acid component used in the production of the polymer (B) include the same compounds as those exemplified for the polymer (P), including preferred specific examples. 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 be referred to as specific tetracarboxylic acid component (B)). The amount of the specific tetracarboxylic acid component (B) used 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 the total tetracarboxylic acid components used in the production of the polymer (B).

[0044] Examples of diamine components for obtaining polymer (B) include the diamines exemplified for polymer (P) above. Among these, at least one diamine selected from the group consisting of the first diamine, a diamine having a urea bond, a diamine having an amide bond, and a diamine having an "-N(D)-" group (also referred to as specific diamine (b) in the present invention) is preferably included. The diamine component may be a single diamine or a combination of two or more diamines. When specific diamine (b) is used, its amount 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 amount of specific diamine (b) is preferably 90 mol % or less, more preferably 80 mol % or less, based on 1 mole of the total diamine components used in the production of polymer (B).

[0045] (Production of Polyamic Acid) Polyamic acid is produced by reacting a diamine component and a tetracarboxylic acid component in an organic solvent. The ratio of the tetracarboxylic acid component and the diamine component used in the polyamic acid production reaction is preferably such that 1 equivalent of the amino group of the diamine component corresponds to 0.5 to 2 equivalents of the acid anhydride group of the tetracarboxylic acid component, more preferably 0.8 to 1.2 equivalents. As with a typical polycondensation reaction, the closer the equivalent of the acid anhydride group of the tetracarboxylic acid component is to 1 equivalent, the higher the molecular weight of the resulting polyamic acid. 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. Polyamic acid can be produced at any concentration, but the polyamic acid concentration is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration initially, with subsequent addition of solvent.

[0046] 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.

[0047] (Production of Polyamic Acid Ester) The polyamic acid ester 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.

[0048] (Production of Polyimide) Polyimide can be obtained by ring-closing (imidizing) a polyimide precursor such as the polyamic acid or polyamic acid ester. The imidization ratio in this specification refers to the ratio of imide groups to the total amount of imide groups derived from tetracarboxylic dianhydride or its derivatives and carboxyl groups (or their derivatives). The imidization ratio does not necessarily have to be 100% and can be adjusted as desired depending on the application and purpose.

[0049] 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. When thermally imidizing the polyimide precursor in solution, the temperature is preferably 100 to 400°C, more preferably 120 to 250°C, and it is preferable to carry out the thermal imidization while removing water produced by the imidization reaction from the system.

[0050] 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.

[0051] When recovering 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.

[0052] When producing the polyimide precursor or polyimide of the present invention, a terminal-capped polymer may be produced using a tetracarboxylic acid component containing a tetracarboxylic dianhydride or a derivative thereof, a diamine component containing a diamine, and an appropriate terminal-capping agent. Terminal-capping polymers have 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. Examples of terminal groups of the polyimide precursor or polyimide of the present invention include amino groups, carboxy groups, acid anhydride groups, and groups derived from terminal-capping agents described below. The amino groups, carboxy groups, and acid anhydride groups can be obtained by a conventional condensation reaction or by terminal-capping with the following terminal-capping agents.

[0053] 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 suitable end-capping agents 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 unsaturated bonds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, or 2-acryloyloxyethyl isocyanate and 2-methacryloyloxyethyl isocyanate. 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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 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.

[0060] (Liquid Crystal Aligning Agent) The liquid crystal aligning agent of the present invention contains the polymer (P) and, if necessary, the other polymers and the organic solvent. The total content of the 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. However, from the viewpoint of forming a uniform and defect-free coating film, it is preferably 1% by mass or more, and from the viewpoint of storage stability of the solution, it is preferably 10% by mass or less. A particularly preferred total polymer content is 2 to 8% by mass. 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, based on the total 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 crosslinkable compound selected from the group consisting of crosslinkable compounds having at least one substituent selected from an oxiranyl group, an oxetanyl group, a blocked isocyanate group, an oxazoline group, a cyclocarbonate group, a hydroxy group, and an alkoxy group, and crosslinkable compounds having a polymerizable unsaturated group; functional silane compounds; metal chelate compounds; curing accelerators; surfactants; antioxidants; sensitizers; preservatives; and compounds for adjusting the dielectric constant and electrical resistance of the resulting liquid crystal alignment film.

[0061] 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 ether, bisphenol A type epoxy resins such as Epicoat 828 (manufactured by Mitsubishi Chemical Corporation), bisphenol F type epoxy resins such as Epicoat 807 (manufactured by Mitsubishi Chemical Corporation), 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-) epoxy resins such as EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.), azole novolac type epoxy resins, triglycidyl isocyanurates such as TEPIC (manufactured by Nissan Chemical Industries, Ltd.), alicyclic epoxy resins such as Celloxide 2021P (manufactured by Daicel Corporation), compounds containing a tertiary nitrogen atom such as N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, or N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, and oxiranyl such as tetrakis(glycidyloxymethyl)methane. compounds having two or more oxetanyl groups described in paragraphs

[0170] to

[0175] of WO 2011 / 132751; compounds having two or more oxetanyl groups; Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (all manufactured by Tosoh Corporation), Takenate B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals, Inc.);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 EPOCROS (manufactured by Nippon Shokubai Co., Ltd.); compounds having a cyclocarbonate group described in paragraphs

[0025] to

[0030] and

[0032] of WO2011 / 155577; 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, 2,2-bis(4-hydroxy-3,5-dihydro Compounds having a hydroxy group or an alkoxy group, such as (hydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane; and compounds represented by glycerin mono(meth)acrylate, glycerin di(meth)acrylate (1,2-,1,3-diglycerolate 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. The content of the crosslinkable 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 aligning agent.

[0062] 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.

[0063] 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. Examples of the functional silane compound include 3-(2-methyl-2-methylpropyl)isocyanurate, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris(3-trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane. 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.

[0064] The solid content concentration of 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 taking into consideration viscosity, volatility, etc., but is preferably 1 to 10% by mass. A particularly preferred range of solid content concentration varies depending on the method used to apply the liquid crystal aligning agent to the substrate. For example, when using a spin coating method, a solid content concentration of 1.5 to 4.5% by mass is particularly preferred. When using a printing method, a solid content concentration of 3 to 9% by mass is particularly preferred, thereby resulting in a solution viscosity of 12 to 50 mPa·s. When using an inkjet method, a solid content concentration of 1 to 5% by mass is particularly preferred, thereby resulting in a solution viscosity of 3 to 15 mPa·s. The temperature when preparing the polymer composition is preferably 10 to 50°C, more preferably 20 to 30°C.

[0065] <Liquid Crystal Alignment Film / Liquid Crystal Display Element> A liquid crystal alignment film can be produced by using the liquid crystal aligning 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 of the present invention is not particularly limited, and it can be applied to various operation modes, such as TN type, STN (Super Twisted Nematic) type, vertical alignment type (including VA-MVA type, VA-PVA type, etc.), IPS mode, FFS mode, and optically compensated bend mode (OCB type). The liquid crystal alignment film of the present invention is particularly suitable for horizontal alignment type liquid crystal display elements such as IPS mode or FFS mode.

[0066] The liquid crystal display element of the present invention can be produced, for example, by a method including the following steps (1) to (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).

[0067] <Step (1): Step of Applying Liquid Crystal Alignment Agent to Substrate> Step (1) is a step of applying the liquid crystal aligning agent of the present invention to a substrate. Specific examples of step (1) are as follows. 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 elements, 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 element, 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.

[0068] Examples of a method for applying the liquid crystal alignment 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 by the inkjet method is preferably used.

[0069] <Step (2): Step of Baking the Applied Liquid Crystal Alignment Agent> Step (2) is a step of baking the liquid crystal alignment agent applied to the substrate to form a film. Specific examples of step (2) are as follows. After applying the liquid crystal alignment 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 alignment agent of the present invention can be performed at any temperature and for any time, and may be performed multiple times. The temperature for reducing the solvent in the liquid crystal alignment agent can be, for example, 40 to 180°C. From the perspective of shortening the process, the baking can be performed at 40 to 150°C. The baking time is not particularly limited, but may be 1 to 10 minutes or 1 to 5 minutes. When thermal imidization of polyamic acid or polyamic acid ester is carried out, a baking step may be added after the above step, for example, at a temperature range of 150 to 300°C or 150 to 250°C. The baking time is not particularly limited, but examples include baking times of 5 to 40 minutes or 5 to 30 minutes. If the film-like material after baking is too thin, the reliability of the liquid crystal display element may decrease, so the film thickness is preferably 5 to 300 nm, more preferably 10 to 200 nm.

[0070] <Step (3): Alignment Treatment of the Film Obtained in Step (2)> Step (3) is a step of optionally 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, or the coating film may be subjected to an alignment ability imparting treatment. Examples of alignment treatment methods for liquid crystal alignment films include rubbing treatment and photo-alignment treatment. Examples of photo-alignment treatment methods include irradiating the surface of the film with polarized radiation in a certain direction and, optionally, performing a heat treatment at a temperature preferably between 150 and 250°C 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, and more preferably between 200 and 400 nm. The rubbing treatment method includes rubbing the coating film in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton. In the photoalignment treatment method, when the radiation is polarized, it may be linearly polarized or partially polarized. Furthermore, when the radiation used is linearly polarized or partially polarized, irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When irradiating with unpolarized radiation, the irradiation direction is preferably oblique.

[0071] <Step (4): Step of preparing a liquid crystal cell> Two substrates on which a liquid crystal alignment film has been formed are prepared as described above, and a liquid crystal is placed between the two substrates arranged opposite each other. Specifically, the following two methods can be mentioned. In the first method, the two substrates are first arranged opposite each other with a gap (cell gap) between them so that the liquid crystal alignment films face each other. Next, the peripheries of the two substrates are bonded together using a sealant, and a liquid crystal composition is injected into the substrate surfaces and the cell gap defined by the sealant to contact the film surface, and then the injection hole is sealed.

[0072] The second method is called the ODF (One Drop Fill) method. A UV-curable sealant, for example, 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. 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. The entire surface of the substrate is then 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 assumes an isotropic phase and then slowly cool it to room temperature to remove flow alignment that occurs during liquid crystal filling. If the coating film is subjected to a rubbing treatment, the two substrates are positioned opposite each other so that the rubbing directions on each coating film are at a predetermined angle, for example, perpendicular or antiparallel. For example, an epoxy resin containing a curing agent and aluminum oxide spheres as spacers can be used as the sealant.

[0073] 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 positive or negative dielectric anisotropy can be used. Note that, hereinafter, a liquid crystal composition having positive dielectric anisotropy is also referred to as a positive liquid crystal, and a liquid crystal composition having negative dielectric anisotropy is also referred to as a negative liquid crystal.

[0074] 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) exhibiting liquid crystal properties within the molecule (e.g., a bimesogenic compound in which two rigid biphenyl structures or terphenyl structures are connected by an alkylene group). The liquid crystal composition may be a liquid crystal composition exhibiting a nematic phase, a smectic phase, or a cholesteric phase. Furthermore, the liquid crystal composition may further contain an additive to improve liquid crystal alignment properties. Such additives include photopolymerizable monomers such as compounds having a polymerizable group; optically active compounds (e.g., S-811 manufactured by Merck Co., Ltd.); antioxidants; ultraviolet absorbers; dyes; antifoaming agents; polymerization initiators; or polymerization inhibitors. Positive liquid crystals include ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, and MLC-7081 manufactured by Merck Co., Ltd. Negative liquid crystals include MLC-6608, MLC-6609, MLC-6610, and MLC-7026-100 manufactured by Merck Co., Ltd. Furthermore, an example of a liquid crystal containing a compound having a polymerizable group is MLC-3023 manufactured by Merck Co., Ltd.

[0075] 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 of: having a liquid crystal layer between a pair of substrates equipped with electrodes, disposing a liquid crystal composition containing a polymerizable compound that polymerizes 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 (hereinafter, this step is also referred to as step (5)). 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) manufactured through a step of having a liquid crystal layer between a pair of substrates equipped with electrodes, disposing a liquid crystal alignment film containing a polymerizable group that polymerizes 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)).

[0076] 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.

[0077] An IPS substrate, which is a comb-teeth electrode substrate used in the IPS mode, has a base material, a plurality of linear electrodes formed on the base material and arranged in a comb-teeth pattern, and a liquid crystal alignment film formed on the base material so as to cover the linear electrodes. Meanwhile, an FFS substrate, which is a comb-teeth electrode substrate used in the FFS mode, 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-teeth pattern, and a liquid crystal alignment film formed on the insulating film so as to cover the linear electrodes.

[0078] FIG. 1 is a schematic cross-sectional view showing an example of an in-plane switching liquid crystal display element of the present invention, which is an example of an IPS-mode liquid crystal display element. In the in-plane switching liquid crystal display element 1 shown in FIG. 1 , liquid crystal 3 is sandwiched between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2c and a counter substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 has a base 2a, a plurality of linear electrodes 2b formed on the base 2a and arranged in a comb-like pattern, and a liquid crystal alignment film 2c formed on the base 2a to cover the linear electrodes 2b. The counter substrate 4 has a base 4b and a liquid crystal alignment film 4a formed on the base 4b. The liquid crystal alignment film 2c is, for example, a liquid crystal alignment film of the present invention. The liquid crystal alignment film 4c is also a liquid crystal alignment film of the present invention. In this in-plane switching 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 field lines L.

[0079] FIG. 2 is a schematic cross-sectional view showing another example of an in-plane switching liquid crystal display element of the present invention, which is an example of an FFS-mode liquid crystal display element. In the in-plane switching liquid crystal display element 1 shown in FIG. 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 includes 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 includes 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. In this IPS LCD element 1, when a voltage is applied to the surface electrodes 2e and the linear electrodes 2g, an electric field is generated between the surface electrodes 2e and the linear electrodes 2g as indicated by electric force lines L.

[0080] The liquid crystal alignment film of the present invention can be used for various purposes other than the above-mentioned purposes, for example, 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 transmission-scattering type liquid crystal dimming element. Furthermore, it can also be used for purposes 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 an insulating film for an electric motor (a gate insulating film for a flexible display).

[0081] 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.

[0082] The present invention will be described in more detail below with reference to examples, but the present invention should not be construed as being limited thereto. The abbreviations for the compounds used and the methods for measuring each physical property are as follows. (Organic Solvents) NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: butyl cellosolve (Tetracarboxylic Dianhydrides) CA-1: Compound represented by the following formula (CA-1). The compound represented by the above formula (CA-1) is a compound falling within the scope of the specific aromatic tetracarboxylic acid component (p). (Diamines) DA-1 to DA-3: Compounds represented by the following formulas (DA-1) to (DA-3), respectively. The compound represented by the above formula (DA-1) is a compound falling within the scope of the specific diamine (p), and the compounds represented by the above formulas (DA-2) to (DA-3) are compounds falling within the scope of other diamines. DA-1 was synthesized according to the synthesis method described in WO 2015 / 030071.

[0083] <Viscosity Measurement> Measurement was carried out 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). <Molecular Weight Measurement> Measurement was carried out using the following room temperature GPC (gel permeation chromatography) apparatus, and Mn and Mw were calculated as polyethylene glycol and polyethylene oxide equivalent values. GPC apparatus: GPC-101 (manufactured by Showa Denko K.K.), columns: GPC KD-803 and GPC KD-805 (manufactured by Showa Denko K.K.) in series, column temperature: 50°C, eluent: N,N-dimethylformamide (containing lithium bromide monohydrate (LiBr.H) as an additive), ２ o-Phosphoric acid (o-Phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L), flow rate: 1.0 mL / min. Standard samples for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000, and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: approximately 12,000, 4,000, and 1,000) (manufactured by Polymer Laboratory Co., Ltd.).

[0084] [Polymer Synthesis] <Synthesis Example 1> DA-1 (2.30 g, 14.0 mmol) and NMP (17.0 g) were added to a 50 mL four-neck flask equipped with a stirrer and dissolved by stirring at room temperature. Thereafter, CA-1 (3.79 g, 12.9 mmol) and NMP (27.8 g) were added and stirred at room temperature for 24 hours to obtain a polyamic acid solution (PAA1) (viscosity: 70 mPa s) with a solids concentration of 12% by mass. The Mn of this polyamic acid was 3,500 and the Mw was 6,300. <Synthesis Example 2> DA-2 (1.50 g, 10.00 mmol) and NMP (11.3 g) were added to a 50 mL four-neck flask equipped with a stirrer and dissolved by stirring at room temperature. Thereafter, CA-1 (2.93 g, 9.95 mmol) and NMP (20.0 g) were added, and the mixture was stirred at 50°C for 24 hours to obtain a polyamic acid solution (PAA2) (viscosity: 302 mPa s) having a solids concentration of 12% by mass. The Mn of this polyamic acid was 5,600 and the Mw was 11,900. <Synthesis Example 3> DA-3 (2.04 g, 15.0 mmol) and NMP (15.1 g) were added to a 50 mL four-neck flask equipped with a stirrer, and the mixture was stirred at room temperature to dissolve. Thereafter, CA-1 (4.06 g, 13.8 mmol) and NMP (29.8 g) were added, and the mixture was stirred at room temperature for 3 hours to obtain a polyamic acid solution (PAA3) (viscosity: 356 mPa s) having a solids concentration of 12% by mass. The polyamic acid had an Mn of 5,200 and an Mw of 13,800.

[0085] Example 1 The polyamic acid solution (PAA1) obtained in Synthesis Example 1 was diluted with NMP, GBL, and BCS, and the mixture was stirred at room temperature for two hours to obtain a liquid crystal aligning agent (AL-1) having a polymer solids to solvents weight ratio (polymer solids:NMP:GBL:BCS) of 4:46:30:20. This liquid crystal aligning agent exhibited no abnormalities such as turbidity or precipitation, confirming that it was a homogeneous solution. Comparative Examples 1 and 2 Liquid crystal aligning agents AL-R1 and AL-R2 were prepared in the same manner as in Example 1, except that PAA2 and PAA3 were used instead of PAA1. The compositions of the liquid crystal aligning agents obtained in the examples and comparative examples are shown in Table 1. In Table 1, the parenthesized values ​​for the composition ratios represent the ratio (parts by mass) of each component relative to 100 parts by mass of the components of the liquid crystal aligning agent.

[0086] [Fabrication of FFS-Driven Liquid Crystal Cell] A liquid crystal cell with a fringe field switching (FFS) mode liquid crystal display element configuration was fabricated. First, a substrate with electrodes was prepared. The substrate was a 30 mm x 35 mm, 0.7 mm thick glass substrate. A solid-patterned ITO electrode constituting a counter electrode was formed on the substrate as the first layer. A SiN (silicon nitride) film deposited by CVD (chemical vapor deposition) was formed on the first counter electrode as the second layer. The second SiN film had a thickness of 300 nm and functioned as an interlayer insulating film. A comb-shaped pixel electrode formed by patterning an ITO film was placed on the second SiN film as the third layer, forming two pixels, a first pixel and a second pixel. Each pixel measured 10 mm long and approximately 5 mm wide. In this case, the first-layer counter electrode and the third-layer pixel electrode were electrically insulated by the action of the second-layer SiN film. The third-layer pixel electrode had a comb-like shape in which multiple 3 μm-wide electrode elements, each bent at a 160° interior angle at the center, were arranged parallel to each other at 6 μm intervals. Each pixel had a first region and a second region, each separated by a line connecting the bent portions of the multiple electrode elements. Comparing the first region and the second region of each pixel, the electrode elements of the pixel electrode constituting them were formed in different directions. That is, with respect to the line connecting the bent portions of the multiple electrode elements, the electrode elements of the pixel electrode in the first region of the pixel were formed to form an 80° angle clockwise, and the electrode elements of the pixel electrode in the second region of the pixel were formed to form an 80° angle counterclockwise. That is, in the first and second regions of each pixel, the direction of rotation (in-plane switching) of the liquid crystal induced by the application of a voltage between the pixel electrode and the counter electrode was opposite to each other. Next, the liquid crystal alignment agent obtained above was filtered through a filter with a pore size of 1.0 μm and then applied by spin coating to the surface of the electrode-attached substrate (first glass substrate) prepared above. Next, the coating was dried on a hot plate at 80 ° C for 2 minutes and then baked in a hot air circulating oven at 230 ° C for 20 minutes to obtain a polyimide film with a thickness of 60 nm.This polyimide film was subjected to a rubbing alignment treatment using a rayon cloth (HY-5318 manufactured by Hyperflex Corp.) (roller diameter: 120 mm, roller rotation speed: 1000 rpm, movement speed: 30 mm / sec, indentation length: 0.4 mm, rubbing direction: 180°C relative to the direction connecting the bent portions of the plurality of electrode elements of the third layer pixel electrode). The film was then cleaned by ultrasonic irradiation in pure water for 1 minute, water droplets were removed by air blowing, and the film was dried in an oven at 80°C for 15 minutes to obtain a substrate with a liquid crystal alignment film. A glass substrate having an ITO electrode formed on the rear surface and columnar spacers with a height of 4 μm was also treated in the same manner as above to obtain a substrate with a liquid crystal alignment film that had been subjected to an alignment treatment. These two substrates with liquid crystal alignment films were combined into a pair. A sealant (Mitsui Chemicals, Inc., XN-1500T) was printed on one substrate, leaving a liquid crystal injection port. The other substrate was then attached, with the liquid crystal alignment film surfaces facing each other and the rubbing directions antiparallel. The pair was then heated at 150°C for 60 minutes to harden the sealant, producing an empty cell with a cell gap of 4 μm. Negative liquid crystal MLC-7026-100 (Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS-mode liquid crystal cell. The resulting liquid crystal cell was then heated at 120°C for 1 hour and left overnight at 23°C before being used for evaluation.

[0087] [Measurement of Absolute Value of Accumulated Charge] The liquid crystal cell prepared above was placed between two polarizing plates arranged with their polarization axes perpendicular to each other. The pixel electrode and the counter electrode were short-circuited to maintain the same potential. An LED backlight was irradiated from below the two polarizing plates. The angle of the liquid crystal cell was adjusted so that the luminance of the LED backlight transmitted through the two polarizing plates was minimized. Next, a 30 Hz AC voltage was applied to the liquid crystal cell, and the VT curve (voltage-transmittance curve) was measured. The AC voltage at which the relative transmittance was 23% was calculated as the driving voltage. For absolute value measurement, the liquid crystal cell was driven by applying a 30 Hz AC voltage. Every three minutes, AC driving was performed until the intra-cell transmittance reached 100%. The VF (voltage-flicker curve) curve was measured immediately after lighting, and the offset voltage at which flicker was minimized was calculated. The change in the minimum offset voltage was then measured every three minutes, and the maximum voltage value was calculated from the change immediately after lighting up to 30 minutes later. In this case, when the amount of change in the maximum offset voltage exceeded 20 mV, it was defined and evaluated as "poor." When the amount of change in the maximum offset voltage did not exceed 20 mV, it was defined and evaluated as "good."

[0088] [Measurement of Relaxation Rate of Accumulated Charge] The angle of the liquid crystal cell was adjusted and the AC voltage (hereinafter referred to as AC voltage (V)) at which the relative transmittance was 23% was measured. Ｂ The calculation of the AC voltage (V Ｂ ) was applied to drive the liquid crystal cell, while simultaneously applying a DC voltage of 1 V, and the cell was driven for 30 minutes. Thereafter, the application of the DC voltage alone was stopped, and the cell was driven for another 15 minutes with only the AC voltage. The evaluation was performed by defining the relative transmittance to be "good" if it relaxed to 25% or less within 10 minutes after the DC voltage application was stopped, and the evaluation was performed by defining the relative transmittance to be "poor" if it took 10 minutes or more for the relative transmittance to decrease to 25% or less. The results are shown in Table 2. The evaluation of the rate of relaxation of accumulated charges according to the above-mentioned method was performed at room temperature.

[0089] [Photoresponsiveness Evaluation] The liquid crystal cell prepared above was placed between two polarizing plates arranged with their polarization axes perpendicular to each other. To evaluate photoresponsiveness, an LED backlight was irradiated from below the two polarizing plates at the start of the measurement. An AC voltage of 30 Hz was applied to the liquid crystal cell, resulting in a relative transmittance of 23%, and the flicker amplitude was monitored during 30 minutes of operation. The flicker amplitude was measured by measuring the transmitted light from the LED backlight through the two polarizing plates and the liquid crystal cell between them using a Data Collection / Data Logger Switch Unit 34410A (manufactured by KEYSIGHT) connected via a photodiode and an I-V conversion amplifier. The flicker level was calculated using the following formula: Flicker Level (%) = {Flicker Amplitude / (2 × z)} × 100. In the formula, z is the luminance measured using the Data Collection / Data Logger Switch Unit 34410A when the liquid crystal cell was driven with an AC voltage of 30 Hz, resulting in a relative transmittance of 23%. The photoresponsiveness was evaluated by defining a change in flicker level of less than 3% as "good" if it remained at that level for 30 minutes from the time the LED backlight was turned on and AC voltage was applied as "good," and a change in flicker level of 3% or more as "poor." The results are shown in Table 2. The evaluation of photoresponsiveness according to the above-mentioned method was carried out at room temperature.

[0090] <Evaluation Results> (Example 1 and Comparative Examples 1-2) The characteristics evaluation results of the liquid crystal display elements obtained using the liquid crystal alignment agents (AL-1) and (AL-R1) to (AL-R2) obtained in Example 1 and Comparative Examples 1-2 are shown in Table 2.

[0091]

[0092] As shown in Table 2, the liquid crystal display element using the liquid crystal alignment film of Example 1 obtained from the liquid crystal alignment agent using a tetracarboxylic acid component containing CA-1, which is a specific aromatic tetracarboxylic acid component (p), and a diamine component containing DA-1, which is a specific diamine (p), had both good relaxation speed of accumulated charges and good photoresponsiveness.

[0093] REFERENCE SIGNS LIST 1 IPS LCD element 2 Comb-tooth electrode substrate 2a Base material 2b Linear electrode 2c Liquid crystal alignment film 2d Base material 2e Planar electrode 2f Insulating film 2g Linear electrode 2h Liquid crystal alignment film 3 Liquid crystal 4 Counter substrate 4a Liquid crystal alignment film 4b Base material L Electric field lines

[0094] The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2022-073221 filed on April 27, 2022 are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims

1. A liquid crystal alignment agent comprising a tetracarboxylic acid component comprising at least one selected from the group consisting of tetracarboxylic dianhydrides represented by the following formula (1) and derivatives thereof, and at least one polymer (P) selected from the group consisting of polyimide precursors obtained using a diamine component comprising a diamine represented by the following formula (2) and polyimides which are imidized products of the polyimide precursor. 【Chemistry 1】 (X ａ This represents a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride or its derivative. ２ This represents a divalent organic group with 6 to 30 carbon atoms containing one or more aromatic groups. ２ Each of these independently represents an alkylene group having 1 to 6 carbon atoms. ２ Each of these independently represents an alkyl group having 1 to 6 carbon atoms. ２ Any hydrogen atom of the aromatic group in this compound may be replaced with a monovalent group.

2. The aforementioned Y ２ The liquid crystal alignment agent according to claim 1, wherein the structure is represented by the following formula (3). 【Chemistry 2】 (L is -CH) ２ -, -O-, -C(=O)-, -N(R)- (where R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group), a cyclohexylene group, or an alkylene group having 2 to 18 carbon atoms. However, any -CH of the alkylene group is also acceptable. ２ The hyphen may be substituted with -O-, -O-C(=O)-, -C(=O)-, -N(R)- (where R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group), -N(R)-C(=O)- (where R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group), a cyclohexylene group, or a phenylene group. R ３ represents a halogen atom, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, any hydrogen atom of the alkyl group or the alkoxy group may be substituted with a halogen atom, and any hydrocarbon group may be substituted with an amino group protected with a tert-butoxycarbonyl group. Each of the multiple values ​​of 'a' is an independent integer between 0 and 4, 'b' is an integer between 1 and 2, and 'c' is an integer between 0 and 1. ３ If there are multiple instances of 'a', they may be the same or different. * represents a combination.

3. The aforementioned L is -O-, -O-C(=O)-, -C(=O)-, -N(R)- (where R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group), -N(R)-C(=O)- (where R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group), -N(R)-C(=O)-N(R)- (where R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group. The two Rs may be the same or different), -(CH ２ ) ｐ -, -O-(CH ２ ) ｐ -O-, -(CH ２ ) ｐ -O-C(=O)-(CH ２ ) ｑ -、 - (CH ２ ) ｐ -N(R)-(CH ２ ) ｑ - (R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group.) - (CH ２ ) ｐ -N(R)-C(=O)-N(R)-(CH ２ ) ｑ - (R represents a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group. The two Rs may be the same or different.) -O-(CH ２ ) ｐ -O-(CH ２ ) ｑ -O-、 -(CH ２ ) ｐ’ -O-C(=O)-(CH ２ ) ｑ -C(=O)-O-(CH ２ ) ｒ’ -、 -(CH ２ ) ｐ’ -C(=O)-O-(CH ２ ) ｑ -O-C(=O)-(CH ２ ) ｒ’ -、 - (CH ２ ) ｐ’ -OC(=O)-Q-C(=O)-O-(CH ２ ) ｑ’ - (Q represents a phenylene group or a cyclohexylene group.) or - (CH ２ ) ｐ’ -C(=O)-O-Q-OC(=O)-(CH ２ ) ｑ’ A liquid crystal alignment agent according to claim 2, selected from either - (where Q represents a phenylene group or a cyclohexylene group). (p is an integer between 1 and 6. q is an integer between 1 and 6. p', q', and r' are each independent integers between 0 and 6. Also, 0 ≤ p' + q' ≤ 10 and 2 ≤ p' + q + r' ≤ 16.)

4. The liquid crystal alignment agent according to claim 1 or 2, wherein the diamine represented by formula (2) is a diamine represented by any of the following formulas (d2-1) to (d2-3). 【Transformation 3】

5. The liquid crystal alignment agent according to claim 1 or 2, wherein the amount of diamine represented by formula (2) used is 5 mol% or more with respect to 1 mole of diamine component used in the production of polymer (P).

6. X in equation (1) above ａ The liquid crystal alignment agent according to claim 1 or 2, wherein the structure is one of the structures selected from the following formulas (Xa-1) and (Xa-2). 【Chemistry 4】 (In equations (Xa-1) to (Xa-2), j and k are integers of 0 or 1, and A １ and A ２ These are, independently, a single bond, -O-, -C(=O)-, -O-C(=O)-, a phenylene group, and -S(=O). ２ - or -NR-C(=O)- (where R represents a hydrogen atom or a methyl group). Multiple A ２ These can be the same or different. * represents a bonding operation.

7. The liquid crystal alignment agent according to claim 6, wherein the above formulas (Xa-1) and (Xa-2) are any of the structures selected from the following formulas (Xa-3) to (Xa-18). 【Transformation 5】 【Transformation 6】 (* indicates a bonding action.)

8. The liquid crystal alignment agent according to claim 1 or 2, wherein the amount used of the tetracarboxylic dianhydride represented by formula (1) and its derivative is 10 mol% or more with respect to 1 mole of the tetracarboxylic acid component used in the production of the polymer (P).

9. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 1 or 2.

10. A liquid crystal display element comprising the liquid crystal alignment film according to claim 9.

11. A method for manufacturing a liquid crystal display element, comprising the following steps (1) to (3). Step (1): A step of applying the liquid crystal alignment agent described in claim 1 or 2 onto a substrate. Step (2): A step of firing the coated liquid crystal alignment agent to obtain a film. Step (3): A step of orientation treatment on the film obtained in step (2).

Images