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

Abstract

The present application provides a liquid crystal alignment film, a liquid crystal alignment agent for obtaining the same, and a liquid crystal display element using the same, the liquid crystal alignment film being capable of being produced by a process of irradiating light and then performing a baking step, having a good liquid crystal alignment property, and having a suppressed unevenness of the liquid crystal alignment property in the film plane. The liquid crystal alignment agent of the present application is characterized by containing at least one polymer (A) selected from the group consisting of a polyimide precursor and a polyimide which is an imidization compound of the polyimide precursor, the polyimide precursor being obtained using a tetracarboxylic acid derivative component and a diamine component containing a diamine represented by the following formula (1). Formula (1) (In the formula, X1 represents a quadrivalent organic group represented by the following formula (g), and Ar represents a divalent organic group having a condensed ring of 7 to 40 carbon atoms in a molecular main chain.) Formula (g) (R1 to R4 each independently represent 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, all of R1 to R4 are hydrogen atoms, or at least one of R1 to R4 represents any one of the above-mentioned groups except the hydrogen atom.)

Description

TECHNICAL FIELD

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

[0002] Conventionally, liquid crystal devices are widely used as display portions of personal computers, smartphones, portable telephones, television displays, and the like. A liquid crystal display device, for example, has a liquid crystal layer interposed between a device substrate and a color filter substrate, pixel electrodes and a common electrode that apply an electric field to the liquid crystal layer, an alignment film that controls the alignment of liquid crystal molecules of the liquid crystal layer, and a thin film transistor (TFT) that switches an electric signal supplied to the pixel electrodes and the like. As a driving method of the liquid crystal molecules, a vertical electric field method such as a TN (Twisted Nematic) method, a VA (Vertical Alignment) method, and the like, and a horizontal electric field method such as an IPS (In-Plane Switching) method, an FFS (Fringe Field Switching) method, and the like are known.

[0003] Now, the most popular liquid crystal alignment film in industry is produced by performing so-called brushing treatment, which is rubbing the surface of a film composed of polyamide acid and / or polyimide produced by imidizing the same, formed on an electrode substrate, in one direction with a cloth of cotton, nylon, polyester, or the like. The brushing treatment is an industrially useful method that is simple and excellent in productivity. However, with the high performance, high definition, and large size of liquid crystal display elements, the influence of damage to the surface of the alignment film, dust, mechanical force, static electricity, and the like caused by the brushing treatment, and further, unevenness in the alignment treatment surface, and the like become serious. As an alignment treatment method instead of the brushing treatment, a photo-alignment method that imparts liquid crystal alignment ability by irradiating polarized radiation is known. The photo-alignment method proposes a photo-alignment method using a photo-isomerization reaction, a photo-alignment method using a photo-crosslinking reaction, a photo-alignment method using a photo-decomposition reaction, and the like (for example, refer to Non-Patent Document 1, Patent Document 1, Patent Document 2).

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 9-297313

[0007] Patent Document 2: Japanese Patent Application Laid-Open (JP-A) No. 2018-526675

[0008] NON-PATENT DOCUMENTS

[0009] Non-patent document 1: "Liquid crystal photo-alignment film" Kimoto, Ichimura, Functional Materials November 1997 Vol. 17, No. 11, pp. 13-22 SUMMARY

[0010] PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] After the polyimide-based liquid crystal alignment agent is applied to a substrate and dried, and then irradiated with polarized ultraviolet rays and then baked, the liquid crystal alignment film manufactured by the above procedure has a problem that the stability of the liquid crystal alignment is not sufficient.

[0012] In particular, when the variation range of the baking temperature at the time of manufacturing and the amount of irradiation of the polarized ultraviolet rays is large, the liquid crystal alignment property in the plane of the liquid crystal alignment film easily becomes uneven (non-uniform), and the unevenness of the twist angle of the liquid crystal in the plane of the liquid crystal display element also becomes large. As a result, when black display is performed using the liquid crystal display element, the brightness in the plane becomes uneven, and the display quality level can be reduced.

[0013] As described above, therefore, even for a liquid crystal alignment film manufactured by a procedure in which baking is performed after irradiation with light, it is required to have a good liquid crystal alignment property, and a liquid crystal alignment film in which the unevenness (non-uniformity) of the liquid crystal alignment property in the plane of the liquid crystal alignment film is suppressed.

[0014] Therefore, in view of the above, the purpose of the present application is to provide a liquid crystal alignment film, and a liquid crystal alignment agent for obtaining the same, and a liquid crystal display element using the same, which can be manufactured by a procedure in which baking is performed after irradiation with light, has a good liquid crystal alignment property, and in which the unevenness (non-uniformity) of the liquid crystal alignment property in the plane of the liquid crystal alignment film is suppressed.

[0015] SOLUTION TO THE PROBLEM

[0016] The present inventors have conducted intensive research in order to solve the above problem, and as a result, have found the following fact, thereby completing the present application, that is, a liquid crystal alignment film formed using a liquid crystal alignment agent containing a polymer obtained using a specific diamine is extremely effective for achieving the above purpose.

[0017] The present application includes the following solution.

[0018] [1] A liquid crystal alignment agent characterized by containing at least one polymer (A) selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic acid derivative component and a diamine component containing a diamine represented by the following formula (1), and a polyimide which is an imidization compound of the polyimide precursor.

[0019]

[0020] (In the formula, X1 represents a tetravalent organic group represented by the following formula (g), and Ar represents a divalent organic group having a condensed ring in a molecular main chain, and the number of carbon atoms is 7 to 40.)

[0021]

[0022] (R1to R4independently represent 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, and all of R1to R4are hydrogen atoms or at least one of R1to R4represents any one of the above-mentioned groups except for a hydrogen atom.)

[0023] Effects of the Invention

[0024] According to the present application, it is possible to provide a liquid crystal alignment film, a liquid crystal alignment agent for obtaining the same, and a liquid crystal display element using the same, which can be produced by a process of performing baking after irradiation with light, has a good liquid crystal alignment property, and has a suppressed unevenness of the liquid crystal alignment property in the plane of the liquid crystal alignment film. DETAILED DESCRIPTION

[0025] Hereinafter, a liquid crystal alignment agent containing a polymer obtained using a specific diamine, a liquid crystal alignment film formed using the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film will be described in detail. The following description of the constitutional requirements is one example of one embodiment of the present application and is not specific to these contents.

[0026] (Liquid crystal alignment agent)

[0027] The liquid crystal alignment agent of the present application contains a polymer (A).

[0028] As a preferred embodiment of the liquid crystal alignment agent of the present application, a liquid crystal alignment agent containing a polymer (A) and an organic solvent can be exemplified.

[0029] Further, the liquid crystal alignment agent of the present application can also contain a polymer other than the polymer (A) (for example, a polymer (B) described later).

[0030] (Polymer (A))

[0031] The polymer (A) is at least one polymer selected from the group consisting of a polyimide formed from a diamine component containing the diamine represented by the above-mentioned formula (1) (also referred to as a specific diamine) and a tetracarboxylic acid derivative component, and an imide compound as the polyimide precursor.

[0032] As specific examples of such polymers, for example, polyimide precursors having imide precursor structures such as amic acid and amic acid ester, polyimides as imidization compounds of the polyimide precursors, polyureas having imide structures, polyamides having imide structures, and the like can be listed. From the viewpoint of use as a liquid crystal aligning agent, the polymer is preferably at least one selected from the group consisting of polyimide precursors and polyimides.

[0033] The polymer (A) can be used singly, and two or more kinds thereof can be used in combination.

[0034] <Specific diamine>

[0035] The specific diamine used in the present application is a diamine represented by the following formula (1).

[0036]

[0037] (In the formula, X1 represents a tetravalent organic group represented by the following formula (g), and Ar represents a divalent organic group having a condensed ring of 7 to 40 carbon atoms in a molecular main chain.)

[0038]

[0039] (R1 to R4 each independently represent a hydrogen atom, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), an alkyl group of 1 to 6 carbon atoms, an alkenyl group of 2 to 6 carbon atoms, an alkynyl group of 2 to 6 carbon atoms, a monovalent organic group of 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, all of R1 to R4 are hydrogen atoms, or at least one of R1 to R4 represents any one of the above-mentioned groups except for a hydrogen atom.)

[0040] As the condensed ring in Ar in the above-mentioned formula (1), for example, condensed polycyclic aromatic hydrocarbons such as naphthalene ring, tetrahydronaphthalene ring, indene ring, fluorene ring, anthracene ring, phenanthrene ring, pyrene ring, and the like; condensed polycyclic heterocycles such as benzofuran ring, thionaphthene ring, indole ring, carbazole ring, coumarin ring, benzopyranone ring, quinoline ring, isoquinoline ring, acridine ring, phthalazine ring, quinazoline ring, quinoxaline ring, and the like can be listed. From the viewpoint of improving the liquid crystal aligning property, the condensed ring is preferably a naphthalene ring, anthracene ring, pyrene ring, indole ring, carbazole ring, coumarin ring, benzopyranone ring, quinoline ring, or isoquinoline ring, and further preferably a naphthalene ring. The above-mentioned condensed ring can optionally have a substituent. As the substituent optionally present in the condensed ring, an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, a halogen atom, and the like can be listed. As the halogen atom, a fluorine atom, chlorine atom, bromine atom, iodine atom, and the like can be listed.

[0041] From the viewpoint of improving the liquid crystal aligning property, the above-mentioned condensed ring is preferably a group represented by the following formula (Rn).

[0042]

[0043] (*1, *2 indicate bonding bonds.)

[0044] In the above (Rn), from the viewpoint of improving the liquid crystal alignment property, the bonding bond "*1" is preferably bonded to the nitrogen atom of the imide ring in the above formula (1).

[0045] It is preferable that Ar in the above formula (1) is a divalent organic group having 7 to 40 carbon atoms represented by the following formula (f).

[0046]

[0047] (A1and A2are each independently a monocyclic ring or a condensed ring optionally having a substituent, A1and A2are not simultaneously a monocyclic ring. X1and X2are each independently a single bond, an oxygen atom or a sulfur atom. Q is an alkylene group having 1 to 8 carbon atoms, or a divalent organic group containing an oxygen atom or a sulfur atom between carbon-carbon bonds of an alkylene group. m and n are each independently an integer of 1 to 3. *1, *2 indicate bonding bonds.)

[0048] As the monocyclic ring in the formula (f), for example, there can be mentioned a benzene ring; a five-membered heterocyclic ring such as a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, a thiazole ring, an imidazole ring, a pyrazole ring and the like; a six-membered heterocyclic ring such as a pyran ring, a pyranone ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring and the like. The monocyclic ring is preferably a benzene ring or a pyridine ring.

[0049] As the condensed ring in A1and A2in the formula (f), the preferable examples are as described as the condensed ring of Ar in the above formula (1).

[0050] The above monocyclic ring and condensed ring further optionally have a substituent. As the substituent which the monocyclic ring and condensed ring optionally have, there can be mentioned an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom and the like.

[0051] X1and X2are preferably an oxygen atom. From the viewpoint of the liquid crystal alignment restricting force, Q is preferably an alkylene group having 2 carbon atoms. m and n are preferably 1.

[0052] Ar in the above formula (1) is preferably a divalent organic group represented by the following formulae (f-1) to (f-23), but is not limited thereto. *1, *2 indicate bonding bonds.

[0053]

[0054]

[0055] In the above (f-1) to (f-23), the bonding bond " * 1" is preferably bonded to the nitrogen atom of the imide ring in the above formula (1) from the viewpoint of improving the liquid crystal alignment property.

[0056] The tetravalent organic group represented by the above (g) is preferably a structure of any of the following formulas (X1-1) to (X1-6) from the viewpoint of improving the liquid crystal alignment property.

[0057]

[0058] (* indicates a bonding bond.)

[0059] If specific examples of the preferred specific examples of the specific diamine are listed, the following formulas (1-1) to (1-5) can be listed, but are not limited thereto.

[0060]

[0061] "Diamine component"

[0062] The diamine component used for obtaining the polymer (A) contains at least one diamine represented by the above formula (1), and can consist of one diamine or can consist of two or more diamines. In the case where the diamine component consists of two or more diamines, a diamine other than the diamine represented by formula (1) can be contained together with the diamine represented by formula (1). The proportion of the diamine represented by formula (1) in the diamine component used for obtaining the polymer (A) is preferably 5 to 100 mol% and more preferably 10 to 100 mol% with respect to 1 mol of the diamine component used.

[0063] As the diamine component used for obtaining the polymer (A), a diamine used together with the diamine represented by formula (1) is not particularly limited, and for example, a compound represented by the following formula (2) or formula (2i) can be listed, in addition to the diamine represented by the above formula (1).

[0064]

[0065] (Y2 represents a divalent organic group represented by the following formula (O). R represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Y 2i represents a divalent organic group represented by the following formula (O').

[0066]

[0067] (Ar represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring. The two Ar's are optionally the same or different, and any hydrogen atom of the ring is optionally substituted with a monovalent substituent. p is an integer of 0 or 1. Q2 represents -(CH2) n -(n is an integer of 2 to 18), or the -(CH2) na group in which at least a part of —CH2— is replaced with any of —O—, —C(=O)— or —O—C(=O)—. * indicates a bonding bond.

[0068]

[0069] (Ar' represents a divalent benzene ring or a biphenyl structure. Both Ar's are optionally the same or different, and any hydrogen atom of the ring is optionally substituted with a monovalent substituent. p' is an integer of 0 or 1. Q 2’ —(CH2)n— (n is an integer of 2 to 18), or a group in which at least a part of —CH2— is replaced with any of —O—, —C(=O)— or —O—C(=O)—. n —(CH2)n— (n is an integer of 2 to 18), or a group in which at least a part of —CH2— is replaced with any of —O—, —C(=O)— or —O—C(=O)—. n a group in which at least a part of —CH2— is replaced with any of —O—, —C(=O)— or —O—C(=O)—. * indicates a bonding bond.

[0070] As the substituent of the above benzene ring, biphenyl structure or naphthalene ring, for example, halogen atom, alkyl group having 1 to 10 carbon atoms, alkenyl group having 2 to 10 carbon atoms, alkoxy group having 1 to 10 carbon atoms, fluoroalkyl group having 1 to 10 carbon atoms, fluoroalkenyl group having 2 to 10 carbon atoms, fluoroalkoxy group having 1 to 10 carbon atoms, carboxyl group, hydroxyl group, alkoxycarbonyl group having 1 to 10 carbon atoms, cyano group, nitro group and the like can be exemplified.

[0071] From the viewpoint of improving the liquid crystal alignment property, the above bivalent organic group represented by the formula (O) is preferably a bivalent organic group represented by any of the following formulae (o-1) to (o-16).

[0072]

[0073] From the viewpoint of improving the liquid crystal alignment property, the above bivalent organic group represented by the formula (O) is preferably a bivalent organic group represented by any of the following formulae (o-1) to (o-16).

[0074] As a preferable specific example of the above diamine represented by the formula (2i), compounds represented by the following formulae (2i-1) to (2i-5) can be exemplified.

[0075]

[0076] From the viewpoint of obtaining the effect of the present application, the polymer (A) preferably contains 1 to 95 mol%, more preferably 1 to 90 mol%, still more preferably 5 to 90 mol% of the diamine represented by the formula (2) or the diamine represented by the formula (2i) relative to 1 mol of the diamine component used in the synthesis of the polymer (A). In this case, the upper limit of the content of the diamine represented by the formula (1) is preferably 99 mol% or less, more preferably 95 mol% or less.

[0077] As the diamine component for obtaining the polymer (A), other diamines than the diamines represented by the above formula (1), the diamines represented by the above formula (2) or formula (2i) can also be used. As the other diamines, there can be mentioned: diamines having a group "-N(D)-" (D represents a urethane-based protective group) in the molecule, carbon atom number 6 to 30, 4,4'-diaminoazobenzene, or the diamines represented by the following formulae (d T (d T -3), the diamines having a photo-orienting group such as the diamines represented by the following formulae (h-1) to (h-6), 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminoanisidine, 4,4'-diaminoazobenzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, and the like aromatic diamines, and further, the diamines used in the polymer (B) described later. As the above urethane-based protective group, there can be mentioned t-butoxy carbonyl, 9-fluorenylmethoxy carbonyl.

[0078] As the diamines having a group "-N(D)-" (D represents a urethane-based protective group) in the molecule, carbon atom number 6 to 30, there can be mentioned the compounds represented by the following formulae (5-1) to (5-10).

[0079]

[0080] (Boc represents t-butoxy carbonyl.)

[0081]

[0082]

[0083] From the viewpoint of obtaining the effects of the present application, the polymer (A) preferably contains 1 to 40 mol%, more preferably 1 to 30 mol%, and further preferably 1 to 25 mol% of other diamines, relative to 1 mol of the diamine component used in the synthesis of the polymer (A).

[0084] <<Tetracarboxylic Acid Derivative Component>>

[0085] In the case of producing the above-mentioned polymer (A), the tetracarboxylic acid derivative component which reacts with the diamine component can use not only tetracarboxylic dianhydride but also tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl ester dihalide, and the like which are derivatives of tetracarboxylic dianhydride. The tetracarboxylic acid derivative component can use one kind of tetracarboxylic dianhydride or its derivative alone or two or more kinds in combination.

[0086] The above-mentioned tetracarboxylic dianhydride or its derivative can cite aromatic, acyclic aliphatic, or alicyclic tetracarboxylic dianhydride or their derivatives. Here, the aromatic tetracarboxylic dianhydride is acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an aromatic ring. The acyclic aliphatic tetracarboxylic dianhydride is acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. Among them, it is not necessary to constitute only a chain hydrocarbon structure, and it can have an alicyclic structure or an aromatic ring structure in a part thereof.

[0087] The alicyclic tetracarboxylic dianhydride is acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an alicyclic structure. Among them, none of the four carboxyl groups is bonded to an aromatic ring. In addition, it is not necessary to constitute only an alicyclic structure, and it can have a chain hydrocarbon structure or an aromatic ring structure in a part thereof.

[0088] Among them, the above-mentioned tetracarboxylic dianhydride or its derivative is preferably a compound represented by the following formula (3) or its derivative. The compound represented by the following formula (3) or its derivative can use one kind alone or two or more kinds in combination.

[0089]

[0090] (X represents a structure selected from the group consisting of the following (x-1) to (x-13).

[0091]

[0092] (R 1 ~R 4 Each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom, a fluorine atom, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. R 5 and R 6 Each independently represents a hydrogen atom or a methyl group. j and k are integers of 0 or 1, and A1and A2each independently represents a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or amide bond. *1 is a bonding bond to one of the anhydride groups, and *2 is a bonding bond to the other of the anhydride groups.

[0093] As more preferable specific examples of the above-mentioned formula (x-1), the following formulae (X1-1) to (X1-6) can be cited. In the formulae, * represents a bonding bond.

[0094]

[0095] As the preferable specific examples of the above-mentioned formula (x-12), (x-13), the following formulae (x-14) to (x-29) can be exemplified.

[0096]

[0097] As the preferable specific examples of the above-mentioned formula (3), the following can be exemplified: X is a structure selected from the above-mentioned formulae (x-1) to (x-8), (x-10) to (x-13), more preferably a structure selected from (x-1) to (x-5), further preferably a structure selected from (x-1).

[0098] The above-mentioned formula (3) is preferably used in a proportion of 1 mol% or more, more preferably 5 mol% or more, further preferably 10 mol% or more, relative to 1 mol of the total of the four carboxylic acid derivative components used in the synthesis of the polymer (A).

[0099] The four carboxylic acid dianhydride and its derivative used in the production of the polymer (A) can also contain a four carboxylic acid dianhydride or its derivative other than the above-mentioned formula (3) (hereinafter referred to as other four carboxylic acid dianhydride or its derivative). As examples of the other four carboxylic acid dianhydride or its derivative, the following formula (3T) can be exemplified. As the four carboxylic acid dianhydride and its derivative used in the production of the polymer (A), in the case where the above-mentioned other four carboxylic acid dianhydride or its derivative is contained, the proportion of the above-mentioned formula (3) is preferably 95 mol% or less, more preferably 90 mol% or less, relative to 1 mol of the total of the four carboxylic acid derivative components used in the synthesis of the polymer (A). The four carboxylic acid dianhydride or its derivative of the following formula (3T) can be used singly or in combination of two or more.

[0100]

[0101] (X T represents a structure selected from the group consisting of the following formulae (t-1) to (t-26).

[0102]

[0103]

[0104] R 8each independently is a hydrogen atom, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), 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. From the aspect of liquid crystal alignment property, R 8 is preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group. represents a bonding bond.

[0105] <Polymers (B)>

[0106] From the viewpoint of reducing afterimage originating from residual DC, the liquid crystal alignment agent of the present application can also contain a polymer (B) other than the polymer (A). If specific examples of such a polymer are listed, polymers selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product of the polyimide precursor obtained using a tetracarboxylic acid derivative component and a diamine component not containing the above specific diamine can be listed.

[0107] As specific examples of the above polyimide precursor, polyamic acid, polyamic acid ester, etc. can be listed.

[0108] The polymer (B) can be used singly, and two or more kinds can also be used in combination.

[0109] As the tetracarboxylic acid derivative component for obtaining the polymer (B), a non-cyclic aliphatic tetracarboxylic dianhydride, an alicyclic tetracarboxylic dianhydride, an aromatic tetracarboxylic dianhydride, or a derivative thereof can be listed. As specific examples of the non-cyclic aliphatic tetracarboxylic dianhydride, the alicyclic tetracarboxylic dianhydride, and the aromatic tetracarboxylic dianhydride, the tetracarboxylic dianhydrides exemplified in the polymer (A) can be listed. Among them, as a preferred tetracarboxylic acid derivative component, a compound represented by the above formula (3) or a derivative thereof is preferred. The above tetracarboxylic acid derivative component can be used singly as one tetracarboxylic dianhydride or a derivative thereof, and two or more kinds can also be used in combination.

[0110] In the polymer (B), as further preferred specific examples of the tetracarboxylic dianhydride represented by the above formula (3) or a derivative thereof, a tetracarboxylic dianhydride represented by the above formula (3) wherein X is selected from the group consisting of the above formulae (x-1) to (x-8), (x-10) to (x-13), or a derivative thereof can be listed.

[0111] As the diamine component used to obtain the polymer (B), the following can be exemplified: the diamines exemplified in the above polymer (A) (in which the above specific diamines are excluded), diamines having at least one nitrogen-containing structure (hereinafter, also referred to as nitrogen-containing structure) selected from the group consisting of nitrogen-containing heterocycle, secondary amino group, and tertiary amino group (in which the above specific diamines are excluded), 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, diamine compounds having a carboxyl group described in the following Formula (3b-1) to Formula (3b-4), and the like, 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzanilide, 4,4'-diaminoazobenzene, 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 urea bond described in the above Formula (h-1) to Formula (h-3), and the like, 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,N-diallylaniline, and the like, diamines having a photopolymerizable group at the terminal, cholestanyloxy-3,5-diaminobenzene, cholestanoyloxy-3,5-diaminobenzene, cholestanoyloxy-2,4-diaminobenzene, 3,5-diaminobenzoic acid cholestanylester, 3,5-diaminobenzoic acid cholestanylester, 3,5-diaminobenzoic acid lanostanylester, 3,6-bis(4-aminobenzoyloxy)cholestan, and the like, diamines having a steroid skeleton, diamines described in the following Formula (V-1) to Formula (V-6), 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and the like, diamines having a siloxane bond, diamines having an oxazoline structure described in the following Formula (Ox-1) to Formula (Ox-2), and the like, and diamines in which a group described in any one of Formula (Y-1) to Formula (Y-167) described in International Publication No. 2018 / 117239 is bonded to two amino groups. The above diamine component can be used as one diamine alone, or two or more diamines in combination.

[0112]

[0113] (In Formula (3b-1), A 1represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -0-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)-, or -N(CH3)CO-, m1 and m2 each independently represent an integer of 0 to 4, and m1 + m2 represents an integer of 1 to 4. In formula (3b-2), m 3 and m 4 each independently represent an integer of 1 to 5. In formula (3b-3), A 2 represents a linear or branched alkyl group having 1 to 5 carbon atoms, and m5 represents an integer of 1 to 5. In formula (3b-4), A 3 and A 4 each independently represent a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -0-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)-, or -N(CH3)CO-, and m6 represents an integer of 1 to 4.

[0114]

[0115] (X v1 ~ X v4 , X p1 ~ X p2 each independently represents -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -0-, -CH2O-, -CH2OCO-, -COO-, or -OCO-, X v5 represents -0-, -CH2O-, -CH2OCO-, -COO-, or -OCO-. Xa represents a single bond, -0-, -NH-, -0-(CH2) m -O- (m represents an integer of 1 to 6), R v1 ~ R v4 , R 1a ~ R 1b each independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms.

[0116]

[0117] As the nitrogen-containing heterocycle which the above-mentioned diamine having a nitrogen-containing structure optionally has, for example, pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, isoquinoline, naphthylidine, quinoxaline, phtalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, hexamethyleneimine, and the like can be exemplified. Among them, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, or acridine is preferable.

[0118] The secondary amino group and the tertiary amino group which the above-mentioned diamine having a nitrogen-containing structure optionally has are represented by the following formula (n), for example.

[0119]

[0120] In the above-mentioned formula (n), R represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. "*" represents a bonding bond which is bonded to a hydrocarbon group.

[0121] As the monovalent hydrocarbon group of R in the above-mentioned formula (n), for example, an alkyl group such as methyl group, ethyl group, propyl group, and the like; a cycloalkyl group such as cyclohexyl group, and the like; an aryl group such as phenyl group, methylphenyl group, and the like, and the like can be exemplified. R is preferably a hydrogen atom or a methyl group.

[0122] As specific examples of the above-mentioned diamine having a nitrogen-containing structure, for example, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, compounds represented by the following formulae (Dp-1) to (Dp-9), compounds represented by the following formulae (z-1) to (z-18) can be exemplified.

[0123]

[0124]

[0125] From the viewpoint of less residual image derived from residual DC, the polymer (B) is preferably a polymer obtained using a diamine selected from the group consisting of the following diamines (which will be collectively referred to as diamines (b) as well), namely, a diamine having a nitrogen-containing structure, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, a diamine compound represented by the above-mentioned formulae (3b-1) to (3b-4) or a diamine having a urea bond.

[0126] From the viewpoint of less residual images derived from residual DC, the polymer (B) can contain 1 mol% or more of the diamine (b) and can contain 5 mol% or more of the diamine (b) with respect to 1 mol of the diamine component used in the synthesis of the polymer (B).

[0127] From the viewpoint of less residual images derived from residual DC, the content ratio of the polymer (A) to the polymer (B) can be 10 / 90 to 90 / 10, can be 20 / 80 to 90 / 10, or can be 20 / 80 to 80 / 20 in terms of the mass ratio of [polymer (A)] / [polymer (B)].

[0128] The use ratio of the tetracarboxylic dianhydride or the derivative thereof represented by the above formula (3) is preferably 1 mol% or more, more preferably 5 mol% or more, and further preferably 10 mol% or more with respect to 1 mol of the total tetracarboxylic derivative component used in the synthesis of the polymer (B).

[0129] <Method for producing polymer (A) and polymer (B)>

[0130] The production of the polymer (A) or (B) is performed by (polycondensing) the above diamine component and the tetracarboxylic derivative component in a solvent. In the case where a part of the polymer (A) or (B) contains an amide acid structure, for example, a polymer having an amide acid structure is obtained by reacting a tetracarboxylic dianhydride component and a diamine component. As the solvent, there is no particular limitation as long as the generated polymer is dissolved.

[0131] As specific examples of the above solvent, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone can be given. Further, in the case where the solvent solubility of the polymer is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the solvents represented by the following formulae [D-1] to [D-3] can be used.

[0132]

[0133] (In formula [D-1], D 1 represents an alkyl group having 1 to 3 carbon atoms, in formula [D-2], D 2 represents an alkyl group having 1 to 3 carbon atoms, in formula [D-3], D 3 represents an alkyl group having 1 to 4 carbon atoms).

[0134] These solvents can be used alone or in combination. Also, even if it is a solvent that does not dissolve the polymer, it can be used in combination with the above solvent within a range where the generated polymer does not precipitate.

[0135] When the diamine component and the tetracarboxylic acid derivative component are reacted in a solvent, the reaction can be carried out at any concentration, preferably at 1 to 50 mass%, more preferably at 5 to 30 mass%. The reaction can be carried out at a high concentration at the initial stage, and then a solvent can also be added.

[0136] In the reaction, the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic acid derivative component is preferably 0.8 to 1.2. As in the usual polycondensation reaction, the closer the molar ratio to 1.0, the greater the molecular weight of the polymer (A), (B) to be produced.

[0137] The polymer containing an amic acid ester structure can be obtained, for example, by the following known methods: [I] a method of reacting the polymer having an amic acid structure obtained by the above-described method with an esterification agent, [II] a method of reacting a tetracarboxylic acid diester with a diamine, [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine, and the like.

[0138] The imidization compound contained in the polymer (A) or (B) of the liquid crystal alignment agent of the present application is obtained by closing the ring of the polymer obtained in the above-described reaction. In the imidization compound, the ring closure rate (also referred to as the imidization rate) of the functional group of the amic acid group or derivative thereof is not necessarily 100%, and can be arbitrarily adjusted depending on the use or purpose.

[0139] As the method of obtaining the imidization compound, there are heat imidization in which a solution of the polymer obtained in the above-described reaction is heated as it is, and catalyst imidization in which a catalyst is added to the solution of the polymer. In the case of heat imidization in a solution, the temperature is 100 to 400°C, preferably 120 to 250°C, and it is preferably performed while removing water produced by the imidization reaction to the outside of the system.

[0140] The above-described catalyst imidization is performed by adding a basic catalyst and an acid anhydride to a solution of the polymer obtained by the reaction, and stirring at -20 to 250°C, preferably at 0 to 180°C. The amount of the basic catalyst is 0.5 to 30 moles, preferably 2 to 20 moles, per mole of the amic acid group, and the amount of the acid anhydride is 1 to 50 moles, preferably 3 to 30 moles, per mole of the amic acid group. As the basic catalyst, there are pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like, and pyridine is preferred because it has a moderate basicity that allows the reaction to proceed. As the acid anhydride, there are acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like, and acetic anhydride is preferred because purification after the reaction becomes easy if it is used. The imidization rate obtained by catalyst imidization can be controlled by adjusting the amount of the catalyst and the reaction temperature and time.

[0141] In the case of recovering the imidated product from the above-mentioned reaction solution, the reaction solution is precipitated by being put into a solvent. As the solvent for precipitation, methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, water, and the like can be given. The polymer precipitated by being put into a solvent is recovered by filtration, and then dried under normal pressure or reduced pressure, at normal temperature or while being heated. Further, if the polymer recovered by precipitation is dissolved again in a solvent and recovered by re-precipitation, the operation is repeated 2 to 10 times, impurities in the polymer can be reduced. As the solvent at this time, for example, alcohols, ketones, hydrocarbons, and the like can be given, and if three or more kinds of solvents selected from among these are used, the efficiency of purification is further increased, and thus this is preferred.

[0142] <Viscosity of a solution of a polymer / molecular weight>

[0143] As the polymer (A) or (B) used in the present application, from the viewpoint of workability, it is preferred that, when it is made into a solution having a concentration of 10 to 15% by weight, it has a solution viscosity of, for example, 10 to 1000 mPa-s, and is not particularly limited. Note that the solution viscosity (mPa-s) of the above-mentioned polymer is a value determined at 25°C using an E-type rotational viscometer for a polymer solution having a concentration of 10 to 15% by mass prepared using a good solvent (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, and the like) for the polymer.

[0144] The weight average molecular weight (Mw) of the above-mentioned polymer (A) or (B) determined by gel permeation chromatography (GPC) is preferably 1000 to 500000, and more preferably 2000 to 500000. Further, the molecular weight distribution (Mw / Mn) indicated by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) determined by GPC is preferably 15 or less, and more preferably 10 or less. By being in such a molecular weight range, good alignment properties and stability of the liquid crystal display element can be ensured.

[0145] <Polymers obtained from a diamine component containing diamines represented by formulae (1-1) to (1-5)>

[0146] As the polymer obtained from a diamine component containing diamines represented by formulae (1-1) to (1-5) above, for example, polyimide precursors having imide precursor structures such as amic acid and amic acid ester, polyimides which are imidation compounds of the polyimide precursors, polyureas having imide structures, polyamides having imide structures, and the like can be given.

[0147] The above polymer is preferably a polyimide precursor obtained by a condensation reaction of a diamine component including the above diamine represented by the formula (1-1) to (1-5) and a tetracarboxylic acid derivative component, or a polyimide which is an imidization compound of the polyimide precursor, and more preferably a polyimide precursor obtained by a condensation reaction of a diamine component including the above diamine represented by the formula (1-1) or (1-2) and a tetracarboxylic acid derivative component, or a polyimide which is an imidization compound of the polyimide precursor. Note that the condensation reaction of the diamine component and the tetracarboxylic acid derivative component and the like are as described in the above <Method for producing polymer (A), polymer (B)>.

[0148] <Other components in liquid crystal alignment agent>

[0149] The liquid crystal alignment agent of the present application contains the polymer (A) and, as necessary, the polymer (B). The liquid crystal alignment agent of the present application can contain other polymers in addition to the polymer (A) and the polymer (B). As the kind of the other polymers, there can be mentioned: polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene or derivatives thereof, poly(styrene-phenylmaleimide) derivatives, poly(meth)acrylates, and the like.

[0150] The liquid crystal alignment agent is used for producing a liquid crystal alignment film, and from the viewpoint of forming a uniform thin film, the form of a coating liquid is adopted. In the liquid crystal alignment agent of the present application, a coating liquid containing the above polymer component and an organic solvent is also preferable. At this time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed depending on the setting of the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, it is preferable to be 1% by weight or more, and from the viewpoint of the storage stability of the solution, it is preferable to be 10% by mass or less. The particularly preferable concentration of the polymer is 2 to 8% by mass.

[0151] The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as it uniformly dissolves the polymer component. As specific examples thereof, the following can be given: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyl lactamide, 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-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(t-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone (which are collectively referred to as "good solvents"), and the like. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, or γ-butyrolactone is 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 alignment agent.

[0152] Further, the organic solvent contained in the liquid crystal alignment agent is preferably a mixed solvent in which a solvent (also referred to as a poor solvent) that improves the coatability of the liquid crystal alignment agent when it is applied and the surface smoothness of the coating film is used in addition to the above-mentioned solvents. The following are specific examples of the organic solvent used in combination, but the present application is not limited thereto.

[0153] For example, mention can be made of: 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-butoxyethane, 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 monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, ethyl 2-(2-ethoxyethoxy)acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether 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.

[0154] Among 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 are preferred.

[0155] As the combination of the preferred solvent as the good solvent and the poor solvent, there can be mentioned: 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-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl methyl carbinol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether; and the like. The content of the poor solvent is preferably 1 to 80% by mass, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass, of the total amount of the solvent contained in the liquid crystal alignment agent. The kind and content of the poor solvent are appropriately selected depending on the coating apparatus, coating conditions, coating environment and the like of the liquid crystal alignment agent.

[0156] The liquid crystal alignment agent of the present application can also contain, in addition to the polymer component and the organic solvent, a component other than these (hereinafter also referred to as an additive component). As such an additive component, there can be mentioned: an adhesion aid for improving the adhesion of the liquid crystal alignment film to the substrate, the adhesion of the liquid crystal alignment film to the sealing material; a compound for improving the strength of the liquid crystal alignment film (hereinafter also referred to as a cross-linking compound); a dielectric, a conductive substance and the like for adjusting the dielectric constant, the resistance of the liquid crystal alignment film.

[0157] As the cross-linking compound, from the viewpoint of good resistance to AC image sticking and high improvement in film strength, there can also be a compound having at least one group selected from the group consisting of an oxirane group, an oxetane group, a protected isocyanate group, a protected isothiocyanate group, a group having an oxazoline ring structure, a group having a morpholine structure, a cyclic carbonate group, a group represented by the following formula (d), and a group represented by the following formula (d1); or a compound selected from a compound represented by the following formula (e) (hereinafter, these will be collectively referred to as compound (C)).

[0158]

[0159] (R2and R3are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH". * indicates a bonding bond. R indicates an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. Z indicates a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. A indicates an (m+n)-valent organic group having an aromatic ring. m indicates an integer of 1 to 6, and n indicates an integer of 0 to 4. R e f indicates a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms.

[0160] As specific examples of the compound having an oxiranyl group, there can be mentioned the compounds described in paragraph

[0037] of Japanese Patent Application Laid-Open No. 10-338880, the compounds having a triazine ring described in International Publication No. 2017 / 170483, and the like, which are compounds having two or more oxiranyl groups. Among them, there can be mentioned the compounds containing a nitrogen atom such as N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, and the compounds represented by the following formulae (r-1) to (r-3).

[0161]

[0162] As specific examples of the compound having an oxetanyl group, there can be mentioned the compounds having two or more oxetanyl groups described in paragraphs

[0170] to

[0175] of International Publication No. 2011 / 132751 and the like.

[0163] As specific examples of the compound having a protected isocyanate group, there can be mentioned the compounds having two or more protected isocyanate groups described in paragraphs

[0046] to

[0047] of Japanese Patent Application Laid-Open No. 2014-224978, the compounds having three or more protected isocyanate groups described in paragraphs

[0119] to

[0120] of International Publication No. 2015 / 141598, and the like, and there can be mentioned the compounds represented by the following formulae (bi-1) to (bi-3).

[0164]

[0165] As specific examples of the compound having a protected isothiocyanate group, there can be mentioned the compounds having two or more protected isothiocyanate groups described in Japanese Patent Application Laid-Open No. 2016-200798.

[0166] ​As a specific example of the compound having a group containing an oxazoline ring structure, a compound containing two or more oxazoline structures described in paragraph

[0115] of Japanese Patent Application Publication No. 2007-286597 can be exemplified.

[0167] As a specific example of the compound having a group containing a Michler's acid structure, a compound having two or more Michler's acid structures described in International Publication No. 2012 / 091088 can be exemplified.

[0168] As a specific example of the compound having a cyclic carbonate group, a compound described in International Publication No. 2011 / 155577 can be exemplified.

[0169] As the alkyl group having 1 to 3 carbon atoms for R2and R3of the group represented by the above formula (d), a methyl group, an ethyl group, a propyl group, and the like can be exemplified.

[0170] As a specific example of the compound having the group represented by the above formula (d), a compound having two or more groups represented by the above formula (d) described in International Publication No. 2015 / 072554, paragraph

[0058] of Japanese Patent Application Publication No. 2016-118753, a compound described in Japanese Patent Application Publication No. 2016-200798, and the like can be exemplified, and a compound represented by the following formulae (hd-1) to (hd-8) can also be exemplified.

[0171]

[0172] As a specific example of the compound having the group represented by the above (d1), a compound described in International Publication No. 2019 / 142927 can be exemplified, and more preferably a compound represented by the following formulae (hd1-1) to (hd1-4) can also be exemplified.

[0173]

[0174] As the (m+n)-valent organic group having an aromatic ring in A of the above-mentioned formula (e), there can be mentioned a (m+n)-valent aromatic hydrocarbon group having 6 to 30 carbon atoms, a (m+n)-valent organic group in which an aromatic hydrocarbon group having 6 to 30 carbon atoms is bonded directly or via a linking group, and a (m+n)-valent group having an aromatic heterocycle. As the aromatic hydrocarbon, there can be mentioned, for example, benzene, naphthalene, and the like. As the aromatic heterocycle, there can be mentioned, for example, a pyrrole ring, an imidazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a quinoline ring, an isoquinoline ring, a carbazole ring, a pyridazine ring, a pyrazine ring, a benzimidazole ring, an indole ring, a quinoxaline ring, an acridine ring, and the like. As the linking group, there can be mentioned an alkylene group having 1 to 10 carbon atoms, -NR- (R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), an alkylene group having 1 to 10 carbon atoms having a fluorine atom, or a group formed by removing one hydrogen atom from the alkylene group, a divalent or trivalent cyclohexane ring, and the like. Note that, any hydrogen atom of the alkylene group is optionally substituted with a fluorine atom or an organic group such as a trifluoromethyl group. If specific examples are mentioned, there can be mentioned the compounds described in International Publication No. 2010 / 074269, the compounds represented by the following formulae (e-1) to (e-10).

[0175]

[0176] The above-mentioned compound is one example of the cross-linkable compound, and is not limited thereto. For example, there can be mentioned the components other than the above-mentioned ones disclosed in International Publication No. 2015 / 060357, pages 53,

[0105] to 55,

[0116] , and the like. Furthermore, the cross-linkable compound can also be combined with two or more kinds.

[0177] The content of the cross-linkable compound in the liquid crystal aligning agent of the present application is preferably 0.5 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent, from the viewpoint of the progress of the cross-linking reaction and the excellent resistance to AC image sticking. More preferably, it is 1 to 15 parts by mass.

[0178] As the adhesion aid described above, for example, the following silane coupling agents can be mentioned: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyl- diethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3- aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3- ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N- ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10- trimethoxysilyl- 1,4,7-triazadecane, 10-triethoxysilyl- 1,4,7-triazadecane, 9- trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3- aminopropyltriethoxysilane, N-bis(oxyethylene)-3-aminopropyltrimethoxysilane, N-bis(oxyethylene)-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3- glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p- styryltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3- methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3- mercaptopyl-methyldimethoxysilane, 3-mercaptopyltrimethoxysilane, 3- isocyanatopropyltriethoxysilane, and the like. In the case where a silane coupling agent is used, it is preferable that the amount of the silane coupling agent be 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, from the viewpoint of the good resistance to AC burn-in.

[0179] The liquid crystal alignment film of the present application is formed using the liquid crystal alignment agent of the present application described above.

[0180] The liquid crystal alignment film of the present application is formed using the liquid crystal alignment agent of the present application described above.

[0181] As a preferred embodiment of the production method of the liquid crystal alignment film of the present application, a production method of a liquid crystal alignment film including the following steps (1) to (3) can be mentioned.

[0182] Method for producing liquid crystal alignment film

[0183] The method for producing a liquid crystal alignment film using the liquid crystal alignment agent of the present application includes a step of applying the liquid crystal alignment agent of the present application to a substrate (step (1)); a step of heating the applied liquid crystal alignment agent to obtain a film (step (2)); and a step of irradiating the film obtained in step (2) with polarized ultraviolet rays (step (3)).

[0184] Further, the method for producing a liquid crystal alignment film of the present application can further include a step of baking the film obtained in step (3) at a temperature of 100°C or higher and higher than that of step (2) (step (4)).

[0185] << Step (1) >>

[0186] As the substrate to which the liquid crystal alignment agent is applied in the present application, there is no particular limitation as long as it is a substrate having high transparency, and a glass substrate, a silicon nitride substrate, an acrylic substrate, a polycarbonate substrate, and the like plastic substrates can be used. At this time, if a substrate formed with an ITO electrode or the like for driving liquid crystals is used, it is preferable in terms of simplification of the process. Further, in a reflective liquid crystal display element, if only a single-sided substrate, an opaque material such as a silicon wafer can also be used, and in this case, an electrode can also be used of a material that reflects light such as aluminum.

[0187] The method of applying the liquid crystal alignment agent is not particularly limited, and industrially, a method using screen printing, offset printing, flexographic printing, or inkjet printing, and the like is generally used. As other application methods, there are dipping method, roll coater method, slit coater method, spin coating method, or spray coating method, and the like, and they can be used according to the purpose.

[0188] << Step (2) >>

[0189] The step (2) is a step of forming a film by baking the liquid crystal alignment agent coated on the substrate. The liquid crystal alignment agent coated on the substrate can be dried by a heating unit such as a hot plate, a heat cycle oven, or an IR (infrared) oven, or thermal imidization of amic acid or amic acid ester in a polymer can be performed. The drying and baking step after coating the liquid crystal alignment agent of the present application can be performed at an arbitrary temperature and time, and can be performed a plurality of times. The temperature at which the organic solvent of the liquid crystal alignment agent is evaporated can be, for example, 40 to 150°C. From the viewpoint of shortening the process, the temperature can be 40 to 120°C. The baking time is not particularly limited, and can be, for example, 1 to 10 minutes or 1 to 5 minutes. In the case of performing thermal imidization of amic acid or amic acid ester in a polymer, a step of baking at a temperature of, for example, 190 to 250°C or 200 to 240°C can be performed after the step of evaporating the above-mentioned organic solvent. The baking time is not particularly limited, and can be, for example, 5 to 40 minutes or 5 to 30 minutes.

[0190] << Step (3) >>

[0191] The step (3) is a step of irradiating the film obtained in the step (2) with polarized ultraviolet rays. The wavelength of the ultraviolet rays is preferably 200 to 400 nm, and more preferably ultraviolet rays having a wavelength of 200 to 300 nm. In order to improve the liquid crystal alignment property, the substrate on which the coating film of the liquid crystal alignment film can be heated at 50 to 250°C while being irradiated with ultraviolet rays. Further, the irradiation amount of the above-mentioned radiation is preferably 1 to 10,000 mJ / cm 2 , and more preferably 100 to 5,000 mJ / cm 2 . The liquid crystal alignment film thus produced can stably align the liquid crystal molecules in a certain direction.

[0192] The higher the extinction ratio of the polarized ultraviolet rays, the higher the anisotropy that can be imparted, and thus is preferred. Specifically, the extinction ratio of linearly polarized ultraviolet rays is preferably 10: 1 or more, and more preferably 20: 1 or more.

[0193] << Step (4) >>

[0194] The step (4) is a step of baking the film obtained in the step (3) at a temperature of 100°C or higher and higher than the temperature in the step (2). The baking temperature is not particularly limited as long as it is 100°C or higher and higher than the baking temperature in the step (2), and is preferably 150 to 300°C, more preferably 150 to 250°C, and further preferably 200 to 250°C. The baking time is preferably 5 to 120 minutes, more preferably 5 to 60 minutes, and further preferably 5 to 30 minutes.

[0195] If the thickness of the liquid crystal alignment film after baking is too thin, the reliability of the liquid crystal display element is sometimes reduced, and therefore the thickness is preferably 5 to 300 nm, and more preferably 10 to 200 nm.

[0196] Further, the contact treatment with water or a solvent can be performed after any of the above-mentioned processes (3) or (4) is performed.

[0197] As the solvent used in the above-mentioned contact treatment, there is no particular limitation as long as it is a solvent that dissolves the decomposition product generated from the liquid crystal alignment film by irradiation of the polarized ultraviolet rays. As specific examples, there can be mentioned water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, 3-methoxypropyl acetate, 3-ethoxypropyl acetate, propyl acetate, butyl acetate, or cyclohexyl acetate, and the like. Among them, from the viewpoint of versatility and safety of the solvent, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate is preferred. Water, 1-methoxy-2-propanol, or ethyl lactate is more preferred. The solvent can be used in combination of one kind or two or more kinds.

[0198] As the above-mentioned contact treatment, that is, the method of treating the liquid crystal alignment film irradiated with the polarized ultraviolet rays with water or a solvent, there can be mentioned dipping treatment, and spray treatment (also referred to as spray coating treatment). From the viewpoint of efficiently dissolving the decomposition product generated from the liquid crystal alignment film by the ultraviolet rays, the treatment time in these treatments is preferably 10 seconds to 1 hour. Among them, dipping treatment for 1 to 30 minutes is preferred. Further, the solvent at the time of the above-mentioned contact treatment can be at ordinary temperature or can be heated, and is preferably 10 to 80°C, and more preferably 20 to 50°C. Further, from the viewpoint of the solubility of the decomposition product, ultrasonic treatment or the like can be performed as necessary.

[0199] After the above-mentioned contact treatment, rinsing (also referred to as elution) with a low-boiling-point solvent such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone, and baking of the liquid crystal alignment film are preferably performed. At this time, either the rinsing or the baking, or both of them can be performed. The temperature of the baking is preferably 150 to 300°C. Among them, 180 to 250°C is preferred. More preferably, 200 to 230°C. Further, the time of the baking is preferably 10 seconds to 30 minutes. Among them, 1 to 10 minutes is preferred.

[0200] (Liquid crystal display element)

[0201] The liquid crystal display element of the present application has the liquid crystal alignment film of the present application. That is, the manufacturing method of the liquid crystal display element of the present application includes the above-described manufacturing method of the liquid crystal alignment film. More preferable is a mode in which the liquid crystal display element of the present application is obtained by a method including the following steps: a step of applying the above-described liquid crystal alignment agent of the present application to a substrate (step (1)); a step of heating the applied liquid crystal alignment agent to obtain a film (step (2)); and a step of irradiating the film obtained in step (2) with polarized ultraviolet rays (step (3)).

[0202] Further, the liquid crystal display element of the present application is preferably obtained by a method further including a step of baking the film obtained in the above-described step (3) at a temperature of 100°C or higher and higher than the temperature of the above-described step (2) (step (4)).

[0203] The liquid crystal alignment film of the present application is preferably used as a liquid crystal alignment film of a liquid crystal display element of an IPS mode, an FFS mode, or the like, and particularly, as a liquid crystal alignment film of a liquid crystal display element of an FFS mode.

[0204] The liquid crystal display element can be manufactured by, after obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal alignment agent of the present application, producing a liquid crystal cell by a known method, and disposing a liquid crystal in the liquid crystal cell.

[0205] <Manufacturing method of liquid crystal display element>

[0206] As one example of the method of producing a liquid crystal cell, a liquid crystal display element of a passive matrix structure is described. Note that it can also be a liquid crystal display element of an active matrix structure in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting an image display.

[0207] Specifically, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segmented electrode is provided on the other substrate. These electrodes can be, for example, ITO electrodes, and are patterned in a manner to enable display of a desired image. Next, an insulating film is provided on each substrate in a manner to cover the common electrode and the segmented electrode. The insulating film can be, for example, a film of SiO2-TiO2 formed by a sol-gel method.

[0208] Next, the liquid crystal alignment film is formed on each substrate by the above method, and the substrate on one side and the substrate on the other side are laminated with the liquid crystal alignment films of the substrates facing each other, and the periphery is bonded with a sealant. In order to control the gap between the substrates, a spacer is usually mixed in advance in the sealant, and in addition, it is preferable that a spacer for controlling the gap between the substrates is also dispersed in advance in the portion of the surface where the sealant is not provided. A portion of the sealant is provided with an opening portion through which liquid crystal can be filled from the outside. Next, a liquid crystal material is injected into the space surrounded by the two substrates and the sealant through the opening portion provided in the sealant, and then the opening portion is sealed with an adhesive. The injection can be performed by a vacuum injection method or a method using capillary phenomenon in the atmosphere. The liquid crystal material can be any of a positive type liquid crystal material or a negative type liquid crystal material. Next, a polarizing plate is provided. Specifically, a pair of polarizing plates is attached to the surfaces of the two substrates opposite to the liquid crystal layer.

[0209] <Properties of liquid crystal display element>

[0210] The liquid crystal display element manufactured using the manufacturing method of the liquid crystal alignment film and the manufacturing method of the liquid crystal display element described above is a liquid crystal display element capable of suppressing the afterimage caused by long-term AC driving in an IPS drive mode or an FFS drive mode. In addition, by performing the process (3) after the removal of the organic solvent in the temperature range of 40 to 150°C in the process (2), the liquid crystal alignment film can be obtained in a smaller number of processes than in the past. The liquid crystal alignment agent of the present application is particularly preferably used in the manufacturing method of the liquid crystal alignment film including the process of performing the process (3) after the removal of the organic solvent in the temperature range of 40 to 150°C in the process (2).

[0211] Examples

[0212] The present application is further explained in detail by the following examples, but the present application is not limited thereto. The abbreviations of the following compounds and the measurement methods of the respective properties are described below. In the examples, Boc represents tert-butoxycarbonyl.

[0213] (Diamines)

[0214] DA-1 to DA-5: Compounds represented by the following formulae (DA-1) to (DA-5), respectively.

[0215]

[0216] (Tetracarboxylic dianhydrides)

[0217] CA-1: Compound represented by the following formula (CA-1).

[0218]

[0219] (organic solvent)

[0220] NMP: N-methyl-2-pyrrolidone

[0221] GBL: γ-butyrolactone

[0222] BCS: butyl cellosolve

[0223] THF: tetrahydrofuran

[0224] DMF: N,N-dimethylformamide

[0225] (reaction reagent)

[0226] Boc2O: di-tert-butyl dicarbonate

[0227] 1 measurement of H-NMR)

[0228] Apparatus: Fourier transform superconducting nuclear magnetic resonance apparatus (FT-NMR) "AVANCE III" (manufactured by BRUKER) 500 MHz

[0229] Solvent: deuterated dimethyl sulfoxide ([D6]-DMSO). Standard substance: tetramethylsilane (TMS)

[0230] measurement of viscosity)

[0231] The measurement was performed using an E-type viscometer TVE-22H (manufactured by Toyo Seiki Co., Ltd.), a sample amount of 1.1 mL, and a conical rotor TE-1 (1° 34', R24) at a temperature of 25°C.

[0232] synthesis of compound (DA-1)

[0233] <synthesis example (DA-1)>

[0234] The compound DA-1 was synthesized according to the following scheme.

[0235] <synthesis of No. 1>

[0236]

[0237] ​To compound C-I (58.9 g, 200 mmol) was added THF (1320 g) and heated to 45°C, then a mixture of Boc20 (26.2 g, 120 mmol) and THF (70 g) was added dropwise over 2 hours. After stirring for 20 hours, crystals were precipitated by adding acetic acid 20% in water (2800 g), and the crystals were washed once with acetic acid 20% in water (200 g), once with water (200 g), and once with hexane (130 g), and dried to obtain No. 1 (36.7 g, 93.0 mmol, 77.5% yield).

[0238] <2> Synthesis of No. 2

[0239]

[0240] To CA-I (7.39 g, 33.0 mmol) was added No. 1 (34.6 g, 87.7 mmol), NMP (346 g), and the reaction was carried out at room temperature for 24 hours, then heated to 60°C, and pyridine (20.9 g, 264 mmol) and acetic anhydride (13.5 g, 132 mmol) were added and the reaction was carried out for 16 hours. Then, crystals were precipitated by adding methanol (632 g), and the crystals were filtered. The crystals were washed twice with a mixture of NMP:methanol = (15 g):(35 g), once with acetonitrile (120 g), and dried to obtain 37 g of a crude of No. 2. Then, to the crude of No. 2 (37 g) and DMF (740 g) was added, and the mixture was heated to 100°C, and the crystals obtained by cooling to room temperature were filtered, washed once with acetonitrile (120 g), and dried to obtain No. 2 (24.5 g, 25.1 mmol, 76.1% yield).

[0241] <DA-I> Synthesis of

[0242]

[0243] To No. 2 (24.5 g, 25.1 mmol) was added ethyl acetate (195 g), 35% hydrochloric acid (9.92 g), and the mixture was heated at 60°C for 28 hours. After the reaction was completed, triethylamine (15.2 g, 150 mmol) was added to neutralize the mixture, and then water (100 g) was added, and the crystals precipitated were filtered, the filter cake was washed once with water (50 g), twice with methanol (40 g), and dried to obtain DA-I (18.9 g, 24.3 mmol, 96.8% yield).

[0244] The results of H-NMR confirmed that the solid was DA-I. 1 The results of H-NMR confirmed that the solid was DA-I.

[0245] 1 H-NMR (500MHz, [D6] -DMSO): δ 7.97-7.94 (m, 6H), 7.50-7.48 (m, 4H), 7.30 (dd, 2H, J=8.9, 2.3 Hz), 6.73 (d, 4H, J=8.8 Hz), 6.53 (d, 4H, J=8.8 Hz), 4.64 (br, 4H), 4.42 (t, 4H, J=3.9 Hz,), 4.25 (t, 4H, J=4.5 Hz), 3.64 (s, 2H), 1.50 (s, 6H).

[0246] (Synthesis of polymer)

[0247] <SYNTHESIS EXAMPLE 1>

[0248] Into a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (4.29 g, 5.52 mmol) and DA-2 (0.23 g, 0.97 mmol) were charged, and NMP was added so as to have a concentration of 10 mass%, and stirred while supplying nitrogen, to obtain a diamine suspension. While stirring the diamine suspension, CA-1 (1.24 g, 5.52 mmol) was added, NMP was added so as to have a concentration of 12 mass%, and stirred at 40°C for 24 hours, to obtain a polyamic acid solution (PAA-1). No abnormality such as turbidity, precipitation, etc. was observed in the polyamic acid solution, and it was confirmed to be a uniform solution.

[0249] <SYNTHESIS EXAMPLES 2 to 5>

[0250] The kind and amount of the monomers used were changed as shown in Table 1 below, and otherwise, polyamic acid solutions (PAA-2) to (PAA-5) were obtained by the same method as in Synthesis Example 1. Note that, in Table 1, as for the values in parentheses, as for the tetracarboxylic acid component, the blending ratio (mole) of each compound with respect to the total amount of the tetracarboxylic acid derivatives used for the synthesis (100 mole) is indicated, and as for the diamine component, the blending ratio (mole) of each compound with respect to the total amount of the diamine used for the synthesis (100 mole) is indicated. As for the organic solvent, the blending ratio (mass) of each organic solvent with respect to the total amount of the organic solvent used for the preparation of the polyimide solution (100 mass) is indicated.

[0251] [Table 1]

[0252]

[0253] (Example 1)

[0254] To a sample tube to which a stirrer was added was added the polyamide solution (PAA-1) obtained in Synthesis Example 1, and further diluted with NMP, GBL, and BCS in such a manner that the solid content concentration was 4 mass%, and the solvent composition was NMP:GBL:BCS = 50:30:20 by mass ratio. This solution was stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (1).

[0255] The constituent components of the liquid crystal alignment agent (1) are shown in Table 2 below.

[0256] In Table 2, the values in parentheses for the organic solvents indicate the blending ratio (mass parts) of each organic solvent contained in the liquid crystal alignment agent with respect to the total amount of the organic solvents, 100 mass parts.

[0257] Using the liquid crystal alignment agent (1), an FFS drive liquid crystal cell was produced in the order shown below, and a property evaluation was performed.

[0258] <Production of Liquid Crystal Display Element>

[0259] In the case of a liquid crystal cell for a fringe field switching (FFS) mode, a first glass substrate and a second glass substrate were set as one set, the first glass substrate had a FOP (Finger on Plate) electrode layer composed of a common electrode-insulating layer-pixel electrode of comb shape formed on the surface, and the second glass substrate had a columnar spacer with a height of 3.5 μm on the surface and an ITO film for preventing electrification formed on the back surface. The above-mentioned pixel electrode had a comb shape in which a plurality of electrode elements were arranged in parallel with a width of 3 μm with a bend of 160° inside angle within the central portion spaced by 6 μm, and one pixel had a first region and a second region with a line connecting the bends of the plurality of electrode elements as a boundary.

[0260] Note that the liquid crystal alignment film formed on the first glass substrate was subjected to alignment treatment in such a manner that the direction bisecting the inside angle of the pixel bend was orthogonal to the alignment direction of the liquid crystal, and the liquid crystal alignment film formed on the second glass substrate was subjected to alignment treatment in such a manner that the alignment direction of the liquid crystal on the first substrate and the alignment direction of the liquid crystal on the second substrate were coincident when the liquid crystal cell was produced.

[0261] The liquid crystal alignment agent was filtered using a filter with an aperture of 1.0 μm, and spin-coated on the above-mentioned substrate with electrodes and the counter substrate, respectively. Subsequently, after drying on a hot plate at 80°C for 2 minutes, the coated film surface was irradiated with ultraviolet rays of a wavelength of 254 nm of linearly polarized light with an extinction ratio of 26:1 at 150 mJ / cm 2 . Further, the substrates were baked at 230°C for 30 minutes to obtain substrates with a liquid crystal alignment film of a film thickness of 100 nm.

[0262] Next, the sealant was printed on one of the substrates of the above set of substrates with the liquid crystal alignment film, and the other substrate was attached to the one with the liquid crystal alignment film face-to-face, and the sealant was cured to produce a cell. The cell was vacuum-injected with liquid crystal (MLC-3019 manufactured by MERCK, at room temperature by the reduced pressure injection method, and the injection port was sealed. An FFS-driven liquid crystal cell was obtained.

[0263] Evaluation of in-plane uniformity of liquid crystal alignment

[0264] The twist angle of the liquid crystal display element was evaluated using OPTIPRO-micro manufactured by SHINTECH. The produced liquid crystal cell was set on a measurement stage, and 20 points were measured in the first pixel plane in a state where no voltage was applied, and the standard deviation was calculated. In the evaluation, a case where the twist angle standard deviation was 1.6 or more was defined as "X", and a case where it was less than 1.6 was defined as "O" and evaluated.

[0265] The results of the evaluation of the liquid crystal display element using the liquid crystal alignment agent (1) are shown in Table 3 below.

[0266] (Example 2)

[0267] The polymer component used in Example 1 was changed as shown in Table 2 below, and otherwise, the liquid crystal alignment agent (2) was obtained by the same method as in Example 1.

[0268] The liquid crystal display element was produced using the liquid crystal alignment agent (2) by the same method as in Example 1, and the property evaluation was performed.

[0269] The results of the evaluation of the liquid crystal display element using the liquid crystal alignment agent (2) are shown in Table 3 below.

[0270] (Comparative Examples 1 to 3)

[0271] The polymer component used in Example 1 was changed as shown in Table 2 below, and otherwise, the liquid crystal alignment agent (R1) to (R3) were obtained by the same method as in Example 1.

[0272] The liquid crystal display element was produced using the liquid crystal alignment agent (R1) to (R3) by the same method as in Example 1, and the property evaluation was performed.

[0273] The results of the evaluation of the liquid crystal display element using the liquid crystal alignment agent (R1) to (R3) are shown in Table 3 below.

[0274] [Table 2]

[0275]

[0276] [Table 3]

[0277]

[0278] As shown in Table 3, it was confirmed that the in-plane uniformity of liquid crystal alignment of Examples 1 to 2 containing the diamine DA-1 was improved as compared with Comparative Examples 1 to 3 not containing the diamine DA-1.

Claims

1. A liquid crystal alignment agent, characterized in that, A polymer (A) comprising at least one polymer selected from the group consisting of a polyimide precursor and an imide compound as the polyimide precursor, wherein the polyimide precursor is obtained using a tetracarboxylic acid derivative component and a diamine component comprising a diamine represented by the following formula (1). In formula (1), X1 represents the tetravalent organic group shown in formula (g) below, and Ar represents the divalent organic group with 7 to 40 carbon atoms having a condensed ring in the main molecular chain. In formula (g), R1 to R4 independently represent 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. All of R1 to R4 are hydrogen atoms, or at least one of R1 to R4 represents any group other than hydrogen atoms among the groups specified above.

2. The liquid crystal alignment agent according to claim 1, wherein, In formula (1), Ar is a divalent organic group with 7 to 40 carbon atoms having the group shown in the following formula (Rn). In equation (Rn), *1 and *2 represent bonding bonds.

3. The liquid crystal alignment agent according to claim 2, wherein, The bonding bond "*1" in formula (Rn) is bonded to the nitrogen atom of the imide ring in formula (1).

4. The liquid crystal alignment agent according to any one of claims 1 to 3, wherein, The tetravalent organic group represented by formula (g) is any one of the following formulas (X1-1) to (X1-6). In equations (X1-1)~(X1-6), * represents a bond.

5. The liquid crystal alignment agent according to claim 4, wherein, The diamine represented by formula (1) is any of the diamines represented by formulas (1-1) to (1-5) below.

6. The liquid crystal alignment agent according to any one of claims 1 to 3, wherein, The diamine component comprises 10 to 100 mol% of the diamine represented by formula (1).

7. The liquid crystal alignment agent according to any one of claims 1 to 3, wherein, The diamine component also contains a diamine represented by formula (2) or formula (2i). In formulas (2) and (2i), Y2 represents a divalent organic group as shown in formula (O); R represents an alkyl group with 1 to 6 carbon atoms; Y 2i This represents the divalent organic group represented by the following formula (O'). In formula (O), Ar represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring; the two Ars may be the same or different, and any hydrogen atom of the ring may be substituted with a monovalent substituent; p is an integer 0 or 1; Q2 represents -(CH2). n - or -(CH2) n A group formed by replacing at least a portion of -CH2- with any one of -O-, -C(=O)-, or -O-C(=O)-, wherein -(CH2-) n In the diagram, n is an integer from 2 to 18; * represents a bond. In formula (O'), Ar' represents a divalent benzene ring or a biphenyl structure; the two Ar's may be the same or different, and any hydrogen atom of the ring may be substituted with a monovalent substituent; p' is an integer 0 or 1; Q2' represents -(CH2). n - or -(CH2) n A group formed by replacing at least a portion of -CH2- with any one of -O-, -C(=O)-, or -O-C(=O)-, wherein -(CH2-) n In the symbol -, n is an integer from 2 to 18; * represents a bond.

8. The liquid crystal alignment agent according to claim 7, wherein, The divalent organic group represented by formula (O) has the structure of any of the following formulas (o-1) to (o-16).

9. The liquid crystal alignment agent according to any one of claims 1 to 3, wherein, The tetracarboxylic acid derivative component comprises a compound or a derivative thereof represented by the following formula (3). In equation (3), X represents the structure selected from the group consisting of (x-1) to (x-13) below. In equations (x-1)~(x-13), R 1 ~R 4 Each of these can independently represent a hydrogen atom, methyl, ethyl, propyl, chlorine atom, fluorine atom, a monovalent organic group containing fluorine atoms with 1 to 6 carbon atoms, or a benzene ring; R 5 and R 6 Each of the following groups represents a hydrogen atom or a methyl group independently; j and k are integers 0 or 1; A1 and A2 independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or amide bond, respectively; *1 is a bond bonded to the anhydride group of one of the groups, and *2 is a bond bonded to the anhydride group of the other group.

10. A liquid crystal alignment film obtained from a liquid crystal alignment agent as described in any one of claims 1 to 9.

11. A liquid crystal display element comprising the liquid crystal alignment film as described in claim 10.

12. A method for manufacturing a liquid crystal alignment film, comprising the following steps (1) to (3), Step (1): A step of coating a liquid crystal alignment agent as described in any one of claims 1 to 9 onto a substrate; Step (2): A step of heating the coated liquid crystal alignment agent to obtain a film; and Step (3): The process of irradiating the film obtained in step (2) with polarized ultraviolet light.

13. The method for manufacturing a liquid crystal alignment film according to claim 12, wherein, It further includes the following process (4), Step (4): A process of firing the film obtained in step (3) at a temperature above 100°C and higher than that of step (2).

14. The method for manufacturing a liquid crystal alignment film according to claim 12 or 13, wherein, The process (2) is a process of heating in a temperature range of 40 to 180°C to obtain a membrane.

15. A method for manufacturing a liquid crystal display element, comprising the method for manufacturing a liquid crystal alignment film as described in any one of claims 12 to 14.

16. A liquid crystal display element comprising a liquid crystal alignment film obtained by the manufacturing method of a liquid crystal alignment film as described in any one of claims 12 to 14.

Images