Diamine, polymer, liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element using the same

Abstract

The present invention provides a liquid crystal alignment agent capable of producing a liquid crystal alignment film by a photo-alignment method, and capable of producing a liquid crystal alignment film having a good voltage holding ratio even when irradiated with backlight for a long period of time. The liquid crystal alignment agent comprises: at least one polymer (A) selected from the group consisting of a polymer obtained using a tetracarboxylic acid derivative component and a diamine component containing a diamine represented by the following formula (1), and an imidized polymer thereof; and an organic solvent.

Description

Technical Field

[0001] The present invention relates to a novel diamine, a polymer, a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element using the same. Background Art

[0002] Liquid crystal display devices have been widely used as display units in personal computers, smartphones, mobile phones, televisions, and the like. These devices include, for example, a liquid crystal layer sandwiched between an element substrate and a color filter substrate; pixel electrodes and a common electrode for applying an electric field to the liquid crystal layer; an alignment film for controlling the alignment of liquid crystal molecules in the liquid crystal layer; and thin-film transistors (TFTs) for switching the electrical signals supplied to the pixel electrodes. Known methods for driving liquid crystal molecules include longitudinal electric field methods such as TN and VA, and transverse electric field methods such as IPS and FFS (fringe field switching).

[0003] At present, the most popular liquid crystal alignment film in the industry is made by performing so-called rubbing treatment, wherein the rubbing treatment is to utilize cloth such as cotton, nylon, polyester, etc. to perform unidirectional friction on the surface of the film of the polyimide formed on the electrode substrate, comprising polyamic acid and / or imidized therein. Rubbing treatment is a simple and industrially useful method with excellent productivity. However, with the high performance, high refinement and large-scale development of liquid crystal display elements, there are various problems as follows: damage to the surface of the alignment film produced by rubbing treatment, dusting, the influence caused by mechanical force and static electricity, and then, the unevenness in the alignment treatment surface. As an orientation treatment method replacing rubbing treatment, it is known to impart liquid crystal orientation ability by irradiating polarized radiation. With regard to the light orientation method, it is proposed to utilize a method for photoisomerization reaction, a method for photocrosslinking reaction, a method for photodecomposition reaction, etc. (with reference to non-patent literature 1, patent literature 1, patent literature 2).

[0004] Prior art literature

[0005] Patent Literature

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

[0007] Patent Document 2: Japanese Patent Application No. 2018-526675

[0008] Non-patent literature

[0009] Non-Patent Document 1: “Liquid Crystal Photo-Alignment Film”, Kidowaki, Ichimura Functional Materials, November 1997, Vol. 17, No. 1113-22. Summary of the Invention

[0010] Problems to be solved by the invention

[0011] In recent years, as the use of liquid crystal display devices has changed, there has been a demand for liquid crystal display devices that can withstand long-term use. To ensure long-term use, it is required that the characteristics of the display remain unchanged even when exposed to light from a backlight unit for a long time. Therefore, there is a demand for liquid crystal alignment films whose display characteristics do not change significantly due to exposure to backlight.

[0012] Moreover, the liquid crystal aligning film manufactured by the process of applying a polyimide-type liquid crystal aligning agent on a board|substrate, drying, irradiating polarized ultraviolet-ray, and then baking has a problem that the stability of a liquid crystal alignment is not necessarily sufficient.

[0013] In summary, the first object of the present invention is to provide a liquid crystal alignment agent that can be used to produce a liquid crystal alignment film by a photo-alignment method, and can produce a liquid crystal alignment film that has a good voltage holding ratio even when irradiated with backlight for a long time, and can produce a liquid crystal alignment film that has a small decrease in voltage holding ratio even when irradiated with backlight for a long time. The second object of the present invention is to provide a liquid crystal alignment agent that, in addition to the first object, can produce a liquid crystal alignment film that has good liquid crystal orientation even when produced by a process of irradiating polarized ultraviolet rays and then firing.

[0014] Solutions for solving problems

[0015] The present inventors have conducted intensive studies to solve the above-mentioned problems and, as a result, have found that the above-mentioned problems can be solved by using specific diamines, thereby completing the present invention.

[0016] Thus, the present invention is based on the above findings and has the following gist.

[0017] A liquid crystal aligning agent comprising at least one polymer (A) selected from the group consisting of polymers obtained using a tetracarboxylic acid derivative component and a diamine component containing a diamine represented by the following formula (1), and imidized polymers thereof, and an organic solvent.

[0018]

[0019] (In the formula, X1 represents a tetravalent organic group represented by the following formula (g), and Ar represents a divalent nitrogen-containing heterocyclic ring. Two Ars may be the same or different.)

[0020]

[0021] (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, wherein all of R1 to R4 represent hydrogen atoms, or at least two of R1 to R4 represent groups other than hydrogen atoms as defined above.)

[0022] Effects of the Invention

[0023] The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention using a photo-alignment method has a good voltage holding ratio even when continuously irradiated with backlight for a long period of time. In addition, the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention using a photo-alignment method has good liquid crystal orientation even when the liquid crystal alignment film is manufactured by a process of irradiating polarized ultraviolet rays and then firing.

[0024] The mechanism for achieving the aforementioned effects of the present invention is not necessarily clear, but the following is one possible reason. Specifically, it is believed that the polymer of the present invention has a cyclobutane ring and an imide ring structure within the molecule. Therefore, even without thermal imidization, it undergoes photodecomposition upon exposure to polarized ultraviolet light. Therefore, even liquid crystal alignment films manufactured using a process involving irradiation with polarized ultraviolet light followed by calcination exhibit excellent liquid crystal alignment properties. Furthermore, it is believed that the heterocyclic structure traps impurities in the liquid crystal layer, resulting in excellent voltage holding ratio even when exposed to backlight for extended periods of time. DETAILED DESCRIPTION

[0025] In this specification, examples of halogen atoms include fluorine, chlorine, bromine, and iodine. Furthermore, in this specification, Boc represents a tert-butyloxycarbonyl group. * represents a bonding bond.

[0026] The liquid crystal aligning agent of the present invention is a liquid crystal aligning agent containing at least one polymer (A) selected from the group consisting of polymers obtained using a tetracarboxylic acid derivative component and a diamine component containing a diamine represented by the following formula (1) (hereinafter also referred to as a specific diamine), and imidized polymers thereof, and an organic solvent. The various conditions are described in detail below.

[0027] <Polymer (A)>

[0028] The polymer (A) used in the present invention is at least one polymer selected from the group consisting of polymers obtained using a tetracarboxylic acid derivative component and a diamine component containing a diamine represented by the following formula (1), and imidized polymers thereof.

[0029] As the specific example of such polymer, for example, can be listed: polyimide precursor with imide precursor structure such as amic acid or amic acid ester, polyimide obtained by imidizing the polyimide precursor, polyurea with imide structure, polyamide with imide structure etc..From the viewpoint of use as liquid crystal aligning agent, the above-mentioned polymer is preferably selected from at least one of polyimide precursor and the polyimide obtained by imidizing the polyimide precursor. It should be noted that, as polyimide precursor, for example, can be listed polyamic acid, polyamic acid ester.

[0030] The polymer (A) may be used alone or in combination of two or more.

[0031] <Specific diamine>

[0032] The specific diamine used in the present invention is a diamine represented by the following formula (1). The diamine represented by the following formula (1) may be used alone or in combination of two or more.

[0033]

[0034] (In the formula, X1 represents a tetravalent organic group represented by the following formula (g), and Ar represents a divalent nitrogen-containing heterocyclic ring. Two Ars may be the same or different.)

[0035]

[0036] (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, wherein all of R1 to R4 represent hydrogen atoms, or at least two of R1 to R4 represent groups other than hydrogen atoms as defined above.)

[0037] The divalent nitrogen-containing heterocycle is a divalent group generated by removing any two hydrogen atoms from the nitrogen-containing heterocycle.

[0038] Examples of the nitrogen-containing heterocycle include five-membered aromatic heterocycles such as pyrrole, imidazole, pyrazole, oxazole, isoxazole, thiazole, and isothiazole; six-membered aromatic heterocycles such as pyridine, pyrimidine, pyridazine, and pyrazine; and polycyclic aromatic heterocycles such as indole and benzimidazole. From the perspective of improving liquid crystal orientation, Ar is preferably a divalent pyridine, pyrimidine, pyridazine, or pyrazine ring.

[0039] Any hydrogen atom of the nitrogen-containing heterocyclic ring may be optionally substituted with a monovalent substituent. Examples of such substituents 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 carboxyl group, a hydroxyl group, an alkyloxycarbonyl group having 1 to 10 carbon atoms, a cyano group, and a nitro group.

[0040] From the viewpoint of improving the liquid crystal orientation, the tetravalent organic group represented by the above-mentioned (g) is preferably any one of the structures of the following formulae (X1-1) to (X1-6).

[0041]

[0042] Preferred specific examples of the specific diamine include, but are not limited to, diamines represented by the following formula (1-1) or (1-2).

[0043]

[0044] <Diamine component>

[0045] The diamine component used to obtain the polymer (A) contains at least one diamine represented by the above formula (1), and may be composed of a single diamine or two or more diamines. When the diamine component is composed of two or more diamines, it may also contain the diamine represented by the formula (1) and a diamine other than the diamine represented by the formula (1). The proportion of the diamine represented by the formula (1) in the diamine component used to obtain the polymer (A) is preferably 5 to 100 mol%, more preferably 10 to 100 mol%, relative to 1 mol of the diamine component.

[0046] The diamine component for obtaining the polymer (A) may contain a diamine represented by formula (1) and a diamine represented by the following formula (2) or a diamine represented by formula (2i). The diamine represented by the following formula (2) or the diamine represented by formula (2i) may be used alone or in combination of two or more.

[0047]

[0048] (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. 2i represents a divalent organic group represented by the following formula (O'). 2i Each independently has the above definition.)

[0049]

[0050] (In formula (O), Ar represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring. Two Ars are optionally the same or different, and any hydrogen atom on the benzene ring, biphenyl structure, or naphthalene 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 -(CH2) n A group in which at least a portion of -CH2- in - is substituted by any of -O-, -C(=O)-, or -O-C(=O)-.

[0051]

[0052] (Ar' represents a divalent benzene ring or a biphenyl structure. Two Ar's are optionally the same or different, and any hydrogen atom on the benzene ring or biphenyl structure is optionally substituted by a monovalent substituent. p' is an integer of 0 or 1. Q 2’ Indicates -(CH2) n -(n is an integer of 2 to 18), or -(CH2) n A group in which at least a portion of the -CH2- of - is substituted by any of -O-, -C(=O)-, or -O-C(=O)-.

[0053] Examples of the substituents of the benzene ring or biphenyl structure 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 carboxyl group, a hydroxyl group, an alkyloxycarbonyl group having 1 to 10 carbon atoms, a cyano group, and a nitro group.

[0054] From the viewpoint of improving the liquid crystal orientation, the divalent organic group represented by the above formula (O) is preferably a divalent organic group represented by the following formulae (o-1) to (o-16).

[0055]

[0056] (In formula (o-14), two m's are optionally the same or different.)

[0057]

[0058] From the viewpoint of improving the liquid crystal orientation, the divalent organic group represented by the above formula (O′) is preferably a divalent organic group represented by the above formulae (o-7) to (o-16).

[0059] Preferred specific examples of the diamine represented by the above formula (2i) include compounds represented by the following formulas (2i-1) to (2i-5).

[0060]

[0061] From the viewpoint of achieving the effects of the present invention, the total proportion of the diamine represented by formula (2) and the diamine represented by formula (2i) in the diamine component for obtaining the polymer (A) is preferably 1 to 95 mol%, more preferably 1 to 90 mol%, and even more preferably 5 to 90 mol%, per 1 mol of the diamine component. In this case, the upper limit of the content of the diamine represented by formula (1) is preferably 99 mol% or less, more preferably 95 mol% or less.

[0062] As the diamine component for obtaining the polymer (A), other diamines other than the diamine represented by the above formula (1), the diamine represented by the above formula (2) and the diamine represented by the formula (2i) can be used. Examples of other diamines include: diamines having 6 to 30 carbon atoms and having a group "-N(D)- (D represents a carbamate-based protective group)" in the molecule; 4,4'-diaminoazobenzene and the following formula (d T -1)~(d T diamines having a photo-aligning group, such as the diamine represented by the following formula (h-3); diamines represented by the following formulas (h-1) to (h-6); aromatic diamines such as 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, and 1,4-bis(4-aminobenzyl)benzene. In addition, diamines used in the polymer (B) described below can be mentioned. As the diamine used in the polymer (B) described below, diamines having at least one nitrogen-containing structure (hereinafter also referred to as a specific nitrogen-containing structure) selected from the group consisting of nitrogen-containing heterocycles, secondary amino groups, and tertiary amino groups are preferably used (excluding the specific diamines described above). Examples of the carbamate-based protecting groups include tert-butyloxycarbonyl and 9-fluorenylmethoxycarbonyl.

[0063]

[0064] Examples of the diamine having 6 to 30 carbon atoms and having the group "-N(D)- (D represents a carbamate-based protecting group)" in the molecule include compounds represented by the following formulas (5-1) to (5-10).

[0065]

[0066] From the viewpoint of achieving the effects of the present invention, the ratio of other diamines in the diamine component for obtaining the polymer (A) is preferably 1 to 40 mol%, more preferably 1 to 30 mol%, and even more preferably 1 to 25 mol%, based on 1 mol of the diamine component.

[0067] (Tetracarboxylic acid derivative component)

[0068] When producing the polymer (A), the tetracarboxylic acid derivative component to be reacted with the diamine component may be not only tetracarboxylic dianhydride but also derivatives of tetracarboxylic dianhydride such as tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl ester dihalide. As the tetracarboxylic acid derivative component, one tetracarboxylic dianhydride or its derivative may be used alone or in combination of two or more.

[0069] The tetracarboxylic dianhydride or its derivatives include aromatic, acyclic aliphatic or alicyclic tetracarboxylic dianhydrides or their derivatives. Here, the aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an aromatic ring.

[0070] Acyclic aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. However, it is not necessary to be composed solely of a chain hydrocarbon structure, and may also partially have an alicyclic structure or an aromatic ring structure.

[0071] Alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to an alicyclic structure. However, none of these four carboxyl groups is bonded to an aromatic ring. Furthermore, it need not consist solely of an alicyclic structure and may also partially contain a chain hydrocarbon structure or an aromatic ring structure.

[0072] Among them, the 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 may be used alone or in combination of two or more.

[0073]

[0074] (X represents a structure selected from the group consisting of the following (x-1) to (x-13).)

[0075]

[0076] (R 1 ~R 4 R each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. 5 and R 6Each independently represents a hydrogen atom or a methyl group. j and k are integers of 0 or 1. A1 and A2 each independently represent a single bond, -O-, -CO-, -COO-, a phenylene group, a sulfonyl group, or an amide group. *1 is a bond to one acid anhydride group, and *2 is a bond to another acid anhydride group. The two A2s may be the same or different.

[0077] More preferable specific examples of the above formula (x-1) include the following formulas (X1-1) to (X1-6).

[0078]

[0079] Preferred specific examples of the above formulae (x-12) and (x-13) include the following formulae (x-14) to (x-29).

[0080]

[0081] Preferred specific examples of the tetracarboxylic dianhydride or its derivative represented by formula (3) include those in which X is selected from the group consisting of formulas (x-1) to (x-8) and (x-10) to (x-13). X may also be selected from the group consisting of (x-12) to (x-13).

[0082] When two or more polymers (A) are used, the tetracarboxylic acid derivative components used to obtain the polymers may be different. For example, polymer (A) may be a mixture of polymer (A1) and polymer (A2), wherein polymer (A1) is obtained from a tetracarboxylic acid derivative component containing 50 mol% or more of acyclic tetracarboxylic dianhydride, alicyclic tetracarboxylic acid derivative, or any one of their derivatives, and polymer (A2) is obtained from a tetracarboxylic acid derivative component containing 50 mol% or more of aromatic tetracarboxylic acid derivative or any one of its derivatives.

[0083] The proportion of tetracarboxylic dianhydride and its derivative represented by formula (3) in the tetracarboxylic acid derivative component for obtaining the polymer (A) is preferably 1 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, based on 1 mol of the tetracarboxylic acid derivative component.

[0084] The tetracarboxylic acid derivative component used in the production of the polymer (A) may contain tetracarboxylic dianhydride or its derivatives other than the above-mentioned formula (3) (hereinafter referred to as other tetracarboxylic dianhydride or its derivatives). Examples of other tetracarboxylic dianhydride or its derivatives include tetracarboxylic dianhydride or its derivatives represented by the following formula (3T). The tetracarboxylic dianhydride or its derivative represented by the following formula (3T) may be used alone or in combination of two or more.

[0085]

[0086] (X T It represents a structure selected from the group consisting of the following (t-1) to (t-26).

[0087]

[0088] R 8 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. 8 A hydrogen atom, a halogen atom, a methyl group, or an ethyl group is preferred, and a hydrogen atom or a methyl group is more preferred.

[0089] <Polymer (B)>

[0090] From the perspective of reducing image sticking caused by residual DC, the liquid crystal aligning agent of the present invention may contain a polymer other than the polymer (A). Specific examples of such polymers include at least one polymer selected from the group consisting of polymers obtained using a tetracarboxylic acid derivative component and a diamine component that does not contain the above-mentioned specific diamine, and imidized polymers thereof.

[0091] Specific examples of such polymers include the aforementioned polyimide precursors and polyimides as imidized polymers thereof. From the perspective of use as a liquid crystal aligning agent, the aforementioned polymer is preferably at least one selected from polyimide precursors and polyimides as imidized polymers thereof.

[0092] The polymer (B) may be used alone or in combination of two or more.

[0093] As the tetracarboxylic acid derivative component for obtaining polymer (B), non-cyclic aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride or their derivatives can be cited. As specific examples of non-cyclic aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride, the tetracarboxylic dianhydride exemplified in polymer (A) can be cited. Among them, as a preferred tetracarboxylic acid derivative component, the compound represented by the above formula (3) or its derivative is preferred. The above-mentioned tetracarboxylic acid derivative component can use one tetracarboxylic dianhydride or its derivative alone, or can use two or more in combination.

[0094] In the polymer (B), further preferred specific examples of the tetracarboxylic dianhydride or its derivative represented by the above formula (3) include tetracarboxylic dianhydride or its derivative represented by the formula (3) wherein X is selected from the above formulas (x-1) to (x-8) and (x-10) to (x-13).

[0095] Examples of the diamine component for obtaining the polymer (B) include the diamines exemplified in the polymer (A) (excluding the specific diamines); diamines having at least one nitrogen-containing structure selected from the group consisting of a nitrogen-containing heterocyclic ring, a secondary amino group, and a tertiary amino group (hereinafter also referred to as a specific nitrogen-containing structure) (excluding the specific diamines); 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol; 2,4-diaminobenzoic acid, 2,5-diaminobenzyl alcohol; Acid, 3,5-diaminobenzoic acid and diamine compounds represented by the following formula (3b-1) to (3b-4) such as diamines having a carboxyl group; 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-indene-6-amine; diamines having a urea bond, such as the diamines represented by the above formulas (h-1) to (h-3); diamines having an amide bond, such as the diamines represented by the above formulas (h-4) to (h-6); diamines having a photopolymerizable group at the end, such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline; cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, 3,5-diamino Diamines having a steroidal skeleton, such as cholesteryl benzoate, lanosteryl 3,5-diaminobenzoate, and 3,6-bis(4-aminobenzoyloxy)cholestane; diamines represented by the following formulas (V-1) to (V-6); diamines having a siloxane bond, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; diamines having an oxazoline structure, such as those represented by the following formulas (Ox-1) to (Ox-2); and diamines having two amino groups bonded to a group represented by any of the formulas (Y-1) to (Y-167) described in International Publication No. 2018 / 117239. These diamine components may be used singly or in combination of two or more.

[0096]

[0097] (In formula (3b-1), A 1represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)- or -N(CH3)CO-, m1 and m2 each independently represent an integer from 0 to 4, and m1+m2 represents an integer from 1 to 4. In formula (3b-2), m3 and m4 each independently represent an integer from 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 represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -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.)

[0098]

[0099] (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-, -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-, X v5 Represents -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-. X a Represents a single bond, -O-, -NH-, or -O-(CH2) m -O-(m is an integer from 1 to 6), R v1 ~R v4 、R 1a ~R 1b Each independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. In formula (V-6), two k are optionally the same or different.

[0100]

[0101] Examples of the nitrogen-containing heterocyclic ring that the diamine having a specific nitrogen-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, tetrahydropyrrole, and hexamethyleneimine. Among them, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, and acridine are preferred.

[0102] The secondary amino group and the tertiary amino group which the diamine having the specific nitrogen atom-containing structure may have are represented by, for example, the following formula (n).

[0103]

[0104] In the above formula (n), R represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. "*1" represents a bond to the hydrocarbon group.

[0105] Examples of the monovalent hydrocarbon group R in the formula (n) include alkyl groups such as methyl, ethyl, and propyl; cycloalkyl groups such as cyclohexyl; and aryl groups such as phenyl and methylphenyl. R is preferably a hydrogen atom or a methyl group.

[0106] Specific examples of the diamine having a specific nitrogen atom-containing structure include 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, compounds represented by the following formulas (Dp-1) to (Dp-9), and compounds represented by the following formulas (z-1) to (z-18).

[0107]

[0108]

[0109] From the viewpoint of less afterimages resulting from residual DC, the polymer (B) is preferably a polymer obtained by using a diamine selected from the group consisting of a diamine having a specific 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 and the diamine compounds represented by the above formulas (3b-1) to (3b-4) or the above-mentioned diamine having a urea bond (these are also collectively referred to as diamine (b)).

[0110] The ratio of the diamine (b) in the diamine component for obtaining the polymer (B) is preferably 1 to 50 mol%, more preferably 5 to 30 mol%, based on 1 mol of the diamine component.

[0111] From the viewpoint of reducing image sticking due to residual DC, the content ratio of polymer (A) to polymer (B) can be 10 / 90 to 90 / 10, 20 / 80 to 90 / 10, or 20 / 80 to 80 / 20 in terms of the mass ratio of [polymer (A)] / [polymer (B)].

[0112] The ratio of the tetracarboxylic dianhydride represented by the above formula (3) and its derivatives in the tetracarboxylic dianhydride component for obtaining the polymer (B) is preferably 1 to 100 mol%, more preferably 5 to 70 mol%, and even more preferably 10 to 50 mol%, based on 1 mol of the tetracarboxylic dianhydride component.

[0113] <Methods for producing polymers (A) and (B)>

[0114] [Polyimide precursor]

[0115] The polyamic acid as a polyimide precursor used in the present invention is carried out, for example, by reacting the above-mentioned diamine component with the above-mentioned tetracarboxylic acid derivative component in a solvent (polycondensation). When the above-mentioned tetracarboxylic acid derivative component includes tetracarboxylic dianhydride, a polymer comprising an amic acid structure can be obtained. As a solvent, as long as it is a solvent that dissolves the generated polymer, there is no particular limitation.

[0116] Specific examples of the above-mentioned solvent include 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 solubility in the solvent, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or solvents represented by the following formulas [D-1] to [D-3] may be used.

[0117]

[0118] (In formula [D-1], D 1 represents an alkyl group having 1 to 3 carbon atoms, wherein D 2 represents an alkyl group having 1 to 3 carbon atoms, wherein D 3 represents an alkyl group having 1 to 4 carbon atoms).

[0119] These solvents may be used alone or in combination. Furthermore, even solvents that do not dissolve the polymer may be mixed with the above solvents to the extent that the generated polymer does not precipitate.

[0120] 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 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction may be carried out at a high concentration initially, and then the solvent may be added.

[0121] In the reaction, the total molar ratio of the diamine components to the tetracarboxylic acid derivative components is preferably 0.8 to 1.2. As in a normal polycondensation reaction, the closer this molar ratio is to 1.0, the greater the molecular weight of the produced polymer (A) and polymer (B).

[0122] The polyamic acid ester (polymer containing an amic acid ester structure) used as a polyimide precursor in the present invention can be obtained, for example, by the following methods: [I] a method of reacting a polymer containing an amic acid structure obtained by the above-mentioned synthesis reaction with an esterifying 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 other known methods.

[0123] [Imidized polymer]

[0124] The imidized polymer contained in the liquid crystal aligning agent of the present invention is obtained by ring-closing a polymer containing the above-mentioned amic acid structure or amic acid ester structure. In the imidized polymer, the ring closure rate (also referred to as the imidization rate) of the functional group possessed by the amic acid group or amic acid ester does not necessarily need to be 100% and can be arbitrarily adjusted according to the application and purpose.

[0125] Examples of methods for imidizing a polymer containing an amic acid structure or an amic acid ester structure to obtain an imidized polymer include thermal imidization in which a solution of the polymer containing an amic acid structure or an amic acid ester structure is directly heated, and catalytic imidization in which a catalyst is added to a solution of the polymer containing an amic acid structure or an amic acid ester structure. The temperature for thermal imidization is preferably 100 to 400°C, more preferably 120 to 250°C. Thermal imidization is preferably performed while removing water generated by the imidization reaction from the system.

[0126] Catalytic imidization can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polymer, preferably stirring at -20 to 250°C, more preferably at 0 to 180°C. The amount of the basic catalyst is preferably 0.5 to 30 times the amide group, more preferably 2 to 20 times, and the amount of the acid anhydride is preferably 1 to 50 times the amide group, more preferably 3 to 30 times. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine and trioctylamine, among which pyridine is preferred because it has a moderate alkalinity for the reaction. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride and pyromellitic anhydride, among which acetic anhydride is preferred because purification after the reaction is easy. The imidization rate based on catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature and reaction time.

[0127] When the imidized polymer generated is recovered from the reaction solution of catalytic imidization, it is sufficient to put the reaction solution into a solvent and precipitate it. Examples of solvents used for precipitation include methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, water, and the like. After the polymer put into the solvent and precipitated is filtered and recovered, it can be dried under normal pressure or reduced pressure, at room temperature, or by heating. In addition, when the polymer recovered by precipitation is repeatedly redissolved in a solvent and reprecipitated and recovered 2 to 10 times, impurities in the polymer can be reduced. As solvents at this time, for example, alcohols, ketone hydrocarbons, and the like can be mentioned. If three or more solvents selected from these are used, the efficiency of purification is further improved, and therefore it is preferred.

[0128] <Polymer Solution Viscosity / Molecular Weight>

[0129] The polymers (A) and (B) used in the present invention preferably have a solution viscosity of, for example, 10 to 1000 mPa·s when prepared as a 10 to 15 wt% solution from the perspective of workability, but are not particularly limited. The solution viscosity (mPa·s) of the polymers described above is measured using an E-type rotational viscometer at 25°C on a 10 to 15 wt% solution of the polymer prepared in a good solvent (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0130] The weight average molecular weight (Mw) of the polymer (A) and the polymer (B) as measured by gel permeation chromatography (GPC) is preferably 1,000 to 500,000, more preferably 2,000 to 500,000. Furthermore, the molecular weight distribution (Mw / Mn), which is the ratio of Mw to the number average molecular weight (Mn) as measured by GPC as polystyrene, is preferably 15 or less, more preferably 10 or less. By having a molecular weight within this range, good orientation and stability of the liquid crystal display element can be ensured.

[0131] <Polymer obtained from a diamine component containing a diamine represented by formula (1-1) or (1-2)>

[0132] Examples of polymers obtained from a diamine component containing a diamine represented by the above formula (1-1) or (1-2) include polyimide precursors having an imide precursor structure such as amic acid and amic acid esters, polyimides obtained by imidating the polyimide precursors, polyureas having an imide structure, and polyamides having an imide structure.

[0133] The polymer is preferably a polymer obtained by a polycondensation reaction of a diamine component comprising a diamine represented by formula (1-1) or (1-2) and a tetracarboxylic acid derivative component, or an imidized polymer thereof. More preferably, it is a polyimide precursor obtained by a polycondensation reaction of a diamine component comprising a diamine represented by formula (1-1) or (1-2) and a tetracarboxylic acid derivative component, or a polyimide obtained by imidating the polyimide precursor. The polycondensation reaction of the diamine component and the tetracarboxylic acid derivative component is as described above in the "Method for Producing Polymers (A) and (B)".

[0134] Liquid crystal alignment agent

[0135] The liquid crystal aligning agent of the present invention contains a polymer (A) and, if necessary, a polymer (B). In addition to polymer (A) and polymer (B), the liquid crystal aligning agent of the present invention may contain other polymers. Examples of other polymers include polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivatives, and poly(meth)acrylates.

[0136] The liquid crystal alignment agent is used to make a liquid crystal alignment film. From the perspective of forming a uniform thin film, it is in the form of a coating liquid. The liquid crystal alignment agent of the present invention is also preferably a coating liquid containing the above-mentioned polymer component and an organic solvent. In this case, the concentration of the polymer component in the liquid crystal alignment agent can be appropriately changed according to the thickness of the coating film to be formed. From the perspective of forming a uniform and defect-free coating film, it is preferably 1% by mass or more, and from the perspective of the storage stability of the solution, it is preferably 10% by mass or less. The concentration of the polymer component is particularly preferably 2 to 8% by mass.

[0137] The content of the polymer (A) used in the present invention is preferably 1 to 100% by mass, more preferably 10 to 100% by mass, and particularly preferably 20 to 100% by mass relative to the polymer component contained in the liquid crystal aligning agent. When the polymer (B) is contained, the content of the polymer (A) is preferably 20 to 90% by mass, more preferably 20 to 80% by mass.

[0138] The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as it is a solvent that uniformly dissolves the polymer component. Specific examples thereof include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, 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-dimethylpropionyl Amine, 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, N-cyclohexyl-2-pyrrolidone (these are also collectively referred to as "good solvents") and the like. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide or γ-butyrolactone are preferred. The content of the good solvent is preferably 20 to 99% by mass of the total solvent contained in the liquid crystal aligning agent, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass.

[0139] In addition, the organic solvent contained in the liquid crystal aligning agent is preferably a mixed solvent containing a solvent (also called a poor solvent) that improves the coating properties and surface smoothness of the coating film when the liquid crystal aligning agent is applied in addition to the above-mentioned solvents. Specific examples of the organic solvents used in combination are described below, but are not limited thereto.

[0140] For example, 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-propyl alcohol, 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, 2-(2-ethoxyethoxy)ethyl 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), etc.

[0141] Among them, 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.

[0142] 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 and γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and 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 carbinol, N-methyl-2-pyrrolidone, γ-butyrolactone, and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, and dipropylene glycol dimethyl ether, etc. The content of the poor solvent is preferably 1 to 80% by mass of the total solvent contained in the liquid crystal aligning agent, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. The type and content of the poor solvent can be appropriately selected according to the coating device, coating conditions, coating environment, etc. of the liquid crystal aligning agent.

[0143] The liquid crystal aligning agent of the present invention may contain additional components other than the polymer component and the organic solvent (hereinafter referred to as additive components). Such additive components include adhesion aids for improving the adhesion between the liquid crystal alignment film and the substrate, the adhesion between the liquid crystal alignment film and the sealing material, compounds for improving the strength of the liquid crystal alignment film (hereinafter referred to as cross-linking compounds), dielectrics for adjusting the dielectric constant and resistance of the liquid crystal alignment film, conductive substances, etc.

[0144] As the above-mentioned cross-linking compound, from the viewpoint of showing good resistance to AC ghosting and high improvement in film strength, it 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 containing an oxazoline ring structure, a group containing a Michaelis acid 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 represented by the following formula (e) (hereinafter, they are also collectively referred to as compound (C)).

[0145]

[0146] (R2 and R3 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH". R represents 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 represents 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 represents an (m+n)-valent organic group having an aromatic ring. m represents an integer of 1 to 6, and n represents an integer of 0 to 4. R e 、R f Each independently represents 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.

[0147] Specific examples of compounds having an oxiranyl group include compounds described in paragraph

[0037] of Japanese Patent Application Laid-Open No. 10-338880 and compounds having a triazine ring skeleton described in International Publication No. 2017 / 170483, and compounds having two or more oxiranyl groups. Among these compounds, nitrogen-containing compounds such as N,N,N',N'-tetracycloxypropyl-m-xylenediamine, 1,3-bis(N,N-dicycloxypropylaminomethyl)cyclohexane, N,N,N',N'-tetracycloxypropyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetracycloxypropyl-p-phenylenediamine, and compounds represented by the following formulas (r-1) to (r-3) may be mentioned.

[0148]

[0149] Specific examples of the compound having an oxetane group include compounds having two or more oxetane groups described in paragraphs

[0170] to

[0175] of International Publication No. 2011 / 132751.

[0150] Specific examples of the compound having a protected isocyanate group include the compounds having two or more protected isocyanate groups described in paragraphs

[0046] to

[0047] of JP-A-2014-224978, and the compounds having three or more protected isocyanate groups described in paragraphs

[0119] to

[0120] of WO-2015 / 141598. Compounds represented by the following formulas (bi-1) to (bi-3) are also acceptable.

[0151]

[0152] Specific examples of the compound having a protected isothiocyanate group include compounds having two or more protected isothiocyanate groups described in JP-A-2016-200798.

[0153] Specific examples of the compound having a group containing an oxazoline ring structure include compounds containing two or more oxazoline ring structures described in paragraph

[0115] of JP-A-2007-286597.

[0154] Specific examples of the compound having a group containing a Michaelis acid structure include compounds having two or more Michaelis acid structures described in International Publication No. 2012 / 091088.

[0155] Specific examples of the compound having a cyclic carbonate group include compounds described in International Publication No. 2011 / 155577.

[0156] Examples of the alkyl group having 1 to 3 carbon atoms represented by R2 and R3 in the group represented by the above formula (d) include methyl, ethyl, and propyl groups.

[0157] Specific examples of the compound having a group represented by the above formula (d) include compounds having two or more groups represented by the above formula (d) described in paragraph

[0058] of International Publication No. 2015 / 072554 and JP-A-2016-118753, compounds described in JP-A-2016-200798, and compounds represented by the following formulas (hd-1) to (hd-8) are also possible.

[0158]

[0159] Specific examples of the compound having the group represented by (d1) include compounds described in International Publication No. 2019 / 142927, and more preferably, compounds represented by the following formulas (hd1-1) to (hd1-4).

[0160]

[0161] Examples of the (m+n)-valent organic group having an aromatic ring in A of the above formula (e) include: an (m+n)-valent aromatic hydrocarbon group having 6 to 30 carbon atoms, an (m+n)-valent organic group formed by directly or via a linking group linking aromatic hydrocarbon groups having 6 to 30 carbon atoms, and an (m+n)-valent group having an aromatic heterocyclic ring. Examples of the above aromatic hydrocarbons include benzene and naphthalene. Examples of the aromatic heterocyclic ring include: 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, and an acridine ring. Examples of the linking group include 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 and having a fluorine atom, or a group obtained by removing one hydrogen atom from the above alkylene group, a divalent or trivalent cyclohexane ring, and the like. It should be noted that any hydrogen atom of the above alkylene group may be substituted with an organic group such as a fluorine atom or a trifluoromethyl group. Specific examples of compounds having a group represented by the above formula (e) include compounds described in International Publication No. 2010 / 074269 and compounds represented by the following formulas (e-1) to (e-10).

[0162]

[0163] The above compounds are examples of crosslinking compounds and are not limited thereto. For example, components other than those disclosed in WO 2015 / 060357, pages 53

[0105] to 55

[0116] , etc. may be mentioned. In addition, two or more crosslinking compounds may be combined.

[0164] The content of the crosslinkable compound in the liquid crystal aligning agent of the present invention 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 allowing a crosslinking reaction to proceed and exhibiting good resistance to AC image sticking, it is more preferably 1 to 15 parts by mass.

[0165] Examples of the adhesion promoter 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, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Benzylcarbonyl-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-aminopropyltriethoxy Silane, 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-glycidoxypropyl Silane coupling agents such as oxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatepropyltriethoxysilane. When using a silane coupling agent, from the viewpoint of exhibiting good resistance to AC image sticking, the amount thereof is preferably 0.1 to 30 parts by mass, and more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0166] <Method for producing a liquid crystal alignment film>

[0167] The method for manufacturing a liquid crystal alignment film using the liquid crystal alignment agent of the present invention is characterized in that the following steps are performed in sequence: a step of applying the above-mentioned liquid crystal alignment agent (step (1)); a step of firing the applied liquid crystal alignment agent (step (2)); a step of irradiating the film obtained in step (2) with polarized ultraviolet rays (step (3)); and a step of firing the film obtained in step (3) at a temperature above 100°C and higher than that of step (2) (step (4)).

[0168] By including a step (step (4)) of firing the film obtained in step (3) at a temperature above 100°C and higher than that of step (2), the following effect can be obtained: the liquid crystal orientation film is re-oriented along the orientation axis generated by polarized ultraviolet irradiation to exhibit liquid crystal orientation.

[0169] <Process (1)>

[0170] As the substrate to be coated with the liquid crystal alignment agent used in the present invention, there is no particular limitation as long as it is a substrate with high transparency, and plastic substrates such as glass substrates, silicon nitride substrates, acrylic substrates, and polycarbonate substrates may also be used. In this case, it is preferred to use a substrate having an ITO electrode or the like for driving the liquid crystal, from the perspective of simplifying the process. In addition, in a reflective liquid crystal display element, if only a single-sided substrate is used, an opaque material such as a silicon wafer may also be used, and in this case, the electrode may also use a light-reflecting material such as aluminum.

[0171] The coating method of the liquid crystal aligning agent is not particularly limited, and is generally performed industrially by screen printing, offset printing, flexographic printing, or inkjet printing. Other coating methods include dipping, roll coating, slit coating, spin coating, and spray coating, and these methods can be used according to the purpose.

[0172] <Process (2)>

[0173] Step (2) is a step of firing the liquid crystal alignment agent applied on the substrate to form a film. After the liquid crystal alignment agent is applied on the substrate, a heating unit such as a hot plate, a heat circulation oven or an IR (infrared) oven can be used to evaporate the solvent, or thermal imidization of the amic acid or amic acid ester in the polymer can be performed. The drying and firing steps after applying the liquid crystal alignment agent of the present invention can be selected at any temperature and time, and can also be performed multiple times. The firing temperature of the liquid crystal alignment agent can be, for example, 40 to 150°C. From the perspective of shortening the process, it can be performed at 40 to 120°C. The firing time is not particularly limited, and 1 to 10 minutes or 1 to 5 minutes can be mentioned. When thermal imidization of the amic acid or amic acid ester in the polymer is performed, after the above-mentioned firing step, a firing step can be performed, for example, at a temperature range of 190 to 250°C or 200 to 240°C. The firing time is not particularly limited, and 5 to 40 minutes or 5 to 30 minutes can be mentioned.

[0174] <Process (3)>

[0175] Step (3) is a step of irradiating the film obtained in step (2) with polarized ultraviolet rays. The wavelength of the ultraviolet rays is preferably 200 to 400 nm, and more preferably 200 to 300 nm. In order to improve the liquid crystal orientation, the substrate coated with the liquid crystal alignment film may be heated at 50 to 250°C while being irradiated with ultraviolet rays. In addition, the irradiation amount of the above-mentioned radiation is preferably 1 to 10,000 mJ / cm 2 , more preferably 100 to 5000 mJ / cm 2 The liquid crystal alignment film produced in this way can stably align the liquid crystal molecules in a fixed direction.

[0176] The higher the extinction ratio of the polarized ultraviolet light, the higher the anisotropy can be imparted, which is preferred. Specifically, the extinction ratio of the linearly polarized ultraviolet light is preferably 10:1 or higher, and more preferably 20:1 or higher.

[0177] <Step (4)>

[0178] Step (4) is a step of calcining the film obtained in step (3) at a temperature of 100°C or higher and higher than that in step (2). The calcination temperature is not particularly limited as long as it is 100°C or higher and higher than the calcination temperature in step (2), but is preferably 150 to 300°C, more preferably 150 to 250°C, and even more preferably 200 to 250°C.

[0179] In addition, the above-mentioned calcination temperature is preferably 100°C or higher and 70°C or higher than the calcination temperature in step (2), more preferably 100°C or higher and 100°C or higher than the calcination temperature in step (2), and further preferably 100°C or higher and 150°C or higher than the calcination temperature in step (2).

[0180] The firing time is preferably 5 to 120 minutes, more preferably 5 to 60 minutes, and even more preferably 5 to 30 minutes.

[0181] Since the reliability of a liquid crystal display element may fall when the thickness of the liquid crystal aligning film after baking is too thin, it is preferably 5-300 nm, and more preferably 10-200 nm.

[0182] Furthermore, after performing any one of the above-mentioned steps (3) and (4), the obtained liquid crystal alignment film may be subjected to a contact treatment using water or a solvent.

[0183] The solvent used in the contact treatment is not particularly limited as long as it dissolves the decomposition products generated by the liquid crystal alignment film due to ultraviolet irradiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, and cyclohexyl acetate. Among these, water, 2-propanol, 1-methoxy-2-propanol, and ethyl lactate are preferred due to their versatility and safety. Water, 1-methoxy-2-propanol, and ethyl lactate are more preferred. The solvent may be a single solvent or a combination of two or more.

[0184] As the above-mentioned contact treatment, that is, a method for treating the liquid crystal alignment film irradiated with polarized ultraviolet rays using water or a solvent, immersion treatment and spray treatment (also referred to as spray treatment) can be cited. From the perspective of efficiently dissolving the decomposition products generated by the liquid crystal alignment film due to ultraviolet rays, the treatment time in these treatments is preferably 10 seconds to 1 hour. Among them, immersion treatment is preferably performed for 1 to 30 minutes. In addition, the solvent during the above-mentioned contact treatment may be room temperature or heated, preferably 10 to 80°C, more preferably 20 to 50°C. In addition, from the perspective of the solubility of the decomposition products, ultrasonic treatment or the like may be performed as needed.

[0185] After the above-mentioned contact treatment, it is preferred to rinse (also referred to as flushing) with a low-boiling-point solvent such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone, and then calcine the liquid crystal alignment film. At this time, either rinsing or calcining may be performed, or both may be performed. The calcining temperature is preferably 150 to 300°C. Among them, 180 to 250°C is preferred. 200 to 230°C is more preferred. In addition, the calcining time is preferably 10 seconds to 30 minutes. Among them, 1 to 10 minutes is preferred.

[0186] The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for liquid crystal display elements of a transverse electric field mode such as an IPS mode or an FFS mode, and is particularly useful as a liquid crystal alignment film for FFS mode liquid crystal display elements. A liquid crystal display element can be obtained by preparing a liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention, preparing a liquid crystal cell by a known method, and using the liquid crystal cell.

[0187] As an example of a method for manufacturing a liquid crystal cell, a passive matrix liquid crystal display element is used as an example. It should be noted that an active matrix liquid crystal display element in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting the image display may also be used.

[0188] Specifically, transparent glass substrates are prepared, with a common electrode provided on one substrate and segment electrodes provided on the other. These electrodes, for example, can be ITO electrodes, patterned to enable the desired image display. Next, an insulating film is provided on each substrate to cover the common electrode and segment electrodes. For example, the insulating film can be a SiO2-TiO2 film formed using a sol-gel method.

[0189] Next, a liquid crystal alignment film is formed on each substrate, and another substrate is superimposed on one substrate in a manner that the liquid crystal alignment film surfaces face each other, and the periphery is bonded with a sealant. In order to control the gap between the substrates, spacers are usually pre-mixed in the sealant. In addition, spacers for controlling the gap between the substrates are preferably also scattered in the surface portion where the sealant is not provided. An opening that can be filled with liquid crystal from the outside is pre-provided in a part of the sealant. Next, a liquid crystal material is injected into the space surrounded by the two substrates and the sealant through the opening provided in the sealant, and then the opening is sealed with an adhesive. The injection can be performed using a vacuum injection method or a method that utilizes capillary action in the atmosphere. The liquid crystal material can be either a positive liquid crystal material or a negative liquid crystal material. Next, a polarizer is set. Specifically, a pair of polarizers are attached to the surface of the two substrates on the opposite side of the liquid crystal layer.

[0190] By using the manufacturing method of the present invention, it is possible to suppress the image sticking caused by long-term AC driving in liquid crystal display elements of IPS drive mode and FFS drive mode. In addition, by performing step (3) after removing the organic solvent in the temperature range of 40 to 150°C in step (2), a liquid crystal alignment film can be obtained with fewer steps than before. The liquid crystal alignment agent of the present invention can be particularly preferably used in a method for manufacturing a liquid crystal alignment film comprising the following steps: performing step (3) after removing the organic solvent in the temperature range of 40 to 150°C in step (2).

[0191] Example

[0192] The present invention will be further described in detail with reference to the following examples, but the present invention is not limited thereto. The abbreviations of the following compounds and the methods for measuring the various properties are as follows.

[0193] (Specific diamine)

[0194] WA-1: A compound represented by the following formula [WA-1]

[0195]

[0196] (Other diamines)

[0197] A1 to A3: Compounds represented by the following formulas [A1] to [A3]

[0198] C1: Compound represented by the following formula [C1]

[0199]

[0200] (Tetracarboxylic dianhydride)

[0201] B1-B2: Compounds represented by the following formulas [B1]-[B2]

[0202]

[0203] (Organic Solvent)

[0204] EA: ethyl acetate

[0205] NMP: N-methyl-2-pyrrolidone

[0206] GBL: gamma-butyrolactone

[0207] BCS: Ethylene glycol monobutyl ether (butyl cellosolve)

[0208] (Reaction Reagent)

[0209] Et3N: triethylamine

[0210] Boc2O: di-tert-butyl dicarbonate

[0211] Ac2O: acetic anhydride

[0212] < 1 H-NMR measurement>

[0213] Apparatus: Fourier transform superconducting nuclear magnetic resonance apparatus (FT-NMR) "AVANCE III" (manufactured by BRUKER), 500 MHz.

[0214] Solvent: Deuterated dimethyl sulfoxide ([D6]-DMSO). Standard substance: Tetramethylsilane (TMS).

[0215] <Molecular weight determination>

[0216] The molecular weight of the polymer was measured as follows using a room temperature gel permeation chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko K.K.) and a column (KD-803 and KD-805 connected in series) (manufactured by Showa Denko K.K.).

[0217] Column temperature: 50°C

[0218] Eluent: N,N-dimethylformamide (as additives, lithium bromide monohydrate (LiBr·H2O) at 30 mmol / L, phosphoric acid anhydrous crystals (o-phosphoric acid) at 30 mmol / L, tetrahydrofuran (THF) at 10 mL / L)

[0219] Flow rate: 1.0 ml / min

[0220] Standard samples for preparing the calibration curve: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000, and 30,000) (manufactured by TOSOH) and polyethylene glycol (molecular weight: approximately 12,000, 4,000, and 1,000) (manufactured by Polymer Laboratories).

[0221] <Viscosity measurement>

[0222] The viscosity was measured 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 conical rotor TE-1 (1°34′, R24).

[0223] [Synthesis of Compound (WA-1)]

[0224] <Monomer Synthesis Example 1>

[0225] Diamine (WA-1) was synthesized according to the route shown below.

[0226] (Synthesis of WA-1-1)

[0227]

[0228] Water (92.8 g) was added to 2,5-diaminopyridine hydrochloride (18.6 g, 102 mmol) to dissolve the mixture. Methanol (93.2 g) was then added to form a mixed solution. Triethylamine (25.9 g, 255 mmol) and Boc2O (21.2 g, 102 mmol) were then added to allow the reaction to proceed. After completion of the reaction, the mixture was separated into an organic layer and an aqueous layer using chloroform (748 g) and water (500 g). The resulting organic layer was washed twice with water (300 g) to form organic layer 1. The resulting aqueous layer was extracted twice with chloroform (374 g) to form organic layer 2. Organic layers 1 and 2 were combined, concentrated, and dried to obtain WA-1-1 (yield: 16.5 g, 79.1 mmol, yield: 77.6%).

[0229] (Synthesis of WA-1-2)

[0230]

[0231] To WA-1-1 (15.2 g, 72.4 mmol) were added NMP (152 g) and tetracarboxylic dianhydride (8.11 g, 36.2 mmol) represented by (B1), and the mixture was stirred at 60°C for 16 hours. Pyridine (17.2 g, 217 mmol) and acetic anhydride (11.2 g, 109 mmol) were then added, and NMP (80 g) was added, followed by stirring at 65°C for 18 hours. The mixture was then returned to room temperature, and the precipitated crystals were filtered and washed three times with acetonitrile (70 g) to obtain WA-1-2 (yield: 14.2 g, 23.4 mmol, yield: 64.6%).

[0232] (Synthesis of WA-1-3)

[0233]

[0234] To WA-1-2 (14.2 g, 23.4 mmol) was added ethyl acetate (143 g). The temperature was raised to 60°C, followed by the addition of 36% hydrochloric acid (3.86 g). After heating for 54 hours, concentrated hydrochloric acid (1.18 g) was further added, and the mixture was heated for 48 hours to complete the deprotection. The precipitated target product was filtered and washed twice with ethyl acetate (45 g) to obtain the hydrochloride salt of WA-1-3 (yield: 11.9 g, 21.6 mmol, yield: 92.3%).

[0235] (Synthesis of WA-1)

[0236]

[0237] To WA-1-3 (11.1 g, 20.1 mmol) were added water (66.9 g) and triethylamine (12.0 g, 119 mmol), and the mixture was stirred at room temperature for 19 hours. The precipitated solid was filtered, washed five times with water (22 g), washed twice with ethanol (89 g), and dried to obtain diamine (WA-1) (yield: 3.97 g, 9.78 mmol, yield: 48.7%).

[0238] According to the following 1 As a result of H-NMR, the solid was confirmed to be WA-1. 1 H-NMR (500MHz, [D6]-DMSO): δ7.90 (d, 2H), 7.09-7.08 (m, 4H), 5.68-5.64 (br, 4H), 3.40 (s, 2H), 1.38 (s, 6H).

[0239] (Polymer Synthesis Example 1)

[0240] B1 (0.784 g, 4.00 mmol) was stirred in NMP (5.80 g) at room temperature for 30 minutes, and then WA-1 (0.650 g, 1.60 mmol), A1 (0.361 g, 1.48 mmol), A2 (0.142 g, 0.600 mmol), and NMP (8.50 g) were added and reacted at room temperature for 15 hours to obtain a polymer solution [1] with a resin solid content concentration of 12% by mass (viscosity: 84 mPa·s). The number average molecular weight of the polymer was 6320, and the weight average molecular weight was 20400.

[0241] (Polymer Synthesis Example 2)

[0242] B1 (0.784 g, 4.00 mmol) was stirred in NMP (5.80 g) at room temperature for 30 minutes, and then C1 (0.647 g, 1.60 mmol), A1 (0.361 g, 1.48 mmol), A2 (0.142 g, 0.600 mmol), and NMP (8.50 g) were added and reacted at room temperature for 15 hours to obtain a polymer solution [2] having a resin solid content concentration of 12% by mass (viscosity: 142 mPa·s). The number average molecular weight of the polymer was 10,300, and the weight average molecular weight was 39,100.

[0243] (Polymer Synthesis Example 3)

[0244] B2 (2.283 g, 7.76 mmol) was stirred in NMP (22.45 g) at room temperature for 30 minutes, and then WA-1 (0.975 g, 2.40 mmol), A3 (1.116 g, 5.60 mmol), and NMP (9.62 g) were added. The mixture was reacted at 50°C for 15 hours to obtain a polymer solution [3] with a resin solid content concentration of 12% by mass (viscosity: 442 mPa·s). The number average molecular weight of the polymer was 11,500, and the weight average molecular weight was 41,300.

[0245] (Polymer Synthesis Example 4)

[0246] B2 (2.283 g, 7.76 mmol) was stirred in NMP (22.43 g) at room temperature for 30 minutes, and then C1 (0.971 g, 2.40 mmol), A3 (1.116 g, 5.60 mmol), and NMP (9.61 g) were added. The mixture was reacted at 50°C for 15 hours to obtain a polymer solution [4] having a resin solids concentration of 12% by mass (viscosity: 442 mPa·s). The number average molecular weight of the polymer was 10,500, and the weight average molecular weight was 40,300.

[0247] <Preparation of Liquid Crystal Alignment Agent>

[0248] (Example 1)

[0249] NMP (0.833 g), GBL (3.00 g), and BCS (2.00 g) were added to the polymer solution [1] (4.17 g) obtained in Polymer Synthesis Example 1, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (V-1). No abnormalities such as turbidity or precipitation were observed in the liquid crystal aligning agent, and it was confirmed to be a uniform solution.

[0250] (Example 2)

[0251] NMP (0.833 g), GBL (3.00 g), and BCS (2.00 g) were added to the polymer solution [1] (2.09 g) obtained in Polymer Synthesis Example 1 and the polymer solution [3] (2.09 g) obtained in Polymer Synthesis Example 3, and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (V-2). No abnormalities such as turbidity or precipitation were observed in the liquid crystal aligning agent, and it was confirmed to be a uniform solution.

[0252] (Example 3)

[0253] NMP (0.833 g), GBL (3.00 g), and BCS (2.00 g) were added to the polymer solution [1] (2.09 g) obtained in Polymer Synthesis Example 1 and the polymer solution [4] (2.09 g) obtained in Polymer Synthesis Example 4, and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (V-3). No abnormalities such as turbidity and precipitation were observed in the liquid crystal aligning agent, and it was confirmed to be a uniform solution.

[0254] (Comparative Example 1)

[0255] NMP (0.833 g), GBL (3.00 g), and BCS (2.00 g) were added to the polymer solution [2] (4.17 g) obtained in Polymer Synthesis Example 2, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (W-1). No abnormalities such as turbidity or precipitation were observed in the liquid crystal aligning agent, and it was confirmed to be a uniform solution.

[0256] <Preparation of a Liquid Crystal Cell for Liquid Crystal Orientation Evaluation>

[0257] The following is a method for producing a liquid crystal box for evaluating the orientation of liquid crystals. First, a substrate with electrodes is prepared. The substrate is a glass substrate with a size of 30 mm × 35 mm and a thickness of 0.7 mm. On the substrate, as the first layer, an IZO electrode constituting a counter electrode is formed on the entire surface. On the counter electrode of the first layer, as the second layer, a SiN (silicon nitride) film formed by a CVD (chemical vapor deposition) method is formed. The second layer of SiN film has a thickness of 500 nm and functions as an interlayer insulating film. On the second layer of SiN film, as the third layer, a comb-shaped pixel electrode formed by patterning the IZO film is arranged to form two pixels, a first pixel and a second pixel. The size of each pixel is 10 mm long and about 5 mm wide. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated due to the action of the second layer of SiN film.

[0258] The pixel electrode of the third layer has a comb-tooth shape in which multiple electrode elements with a width of 3 μm are arranged in parallel at intervals of 6 μm, and the central part is bent at an internal angle of 160°. A pixel has a first area and a second area with the line connecting the bent parts of the multiple electrode elements as the boundary.

[0259] Comparing the first and second regions of each pixel reveals that the electrode elements constituting their pixel electrodes are formed in different directions. Specifically, with reference to the direction of the polarization plane of polarized ultraviolet light (described later) projected onto a line segment of the substrate, in the first region of the pixel, the electrode elements of the pixel electrode are formed at an angle of +80° (clockwise), while in the second region of the pixel, the electrode elements of the pixel electrode are formed at an angle of -80° (clockwise). In other words, in the first and second regions of each pixel, the directions of the liquid crystal rotation within the substrate plane (in-plane switching), induced by the application of a voltage between the pixel electrode and the opposing electrode, are configured to be opposite to each other.

[0260] Next, the liquid crystal alignment agent obtained in Examples 1 to 3 and Comparative Example 1 was filtered using a filter with a pore size of 1.0 μm, and then applied to the prepared substrate with electrodes by spin coating. Then, it was dried on a hot plate set at 80°C for 120 seconds. Next, an exposure device (manufactured by USHIO Electric Co., Ltd., APL-L050121S1S-APW01) was used to irradiate linearly polarized ultraviolet light from a direction perpendicular to the substrate through a wavelength selection filter and a polarizer. At this time, the polarization plane direction was set in such a way that the direction of the polarization plane of the polarized ultraviolet light projected onto the line segment of the substrate became a direction inclined 80° relative to the third layer of IZO comb electrodes. Next, it was calcined at 230°C for 30 minutes in an IR (infrared) type oven to obtain a substrate with a polyimide liquid crystal alignment film having a film thickness of 100 nm that had been subjected to an orientation treatment. In addition, as a counter substrate, a glass substrate with a columnar spacer having an ITO electrode formed on the back and a height of 4μm was also obtained in the same manner as above with a substrate having a polyimide liquid crystal alignment film that had been subjected to an orientation treatment. The two substrates with liquid crystal alignment films were set as a group, and a sealant (Mitsui Chemicals, Inc., XN-1500T) was printed in the form of a liquid crystal injection port remaining on one substrate. The other substrate was placed with the liquid crystal alignment film surface facing each other, and the polarization plane of the polarized ultraviolet rays was projected onto the direction of the line segment of the substrate in parallel and pressed together. Then, the sealant was cured to produce an empty box with a cell gap of 4μm. Liquid crystal MLC-7026 (negative liquid crystal made by MERCK) was injected into the empty box by a reduced pressure injection method, and the injection port was sealed to obtain an FFS liquid crystal box. Then, the obtained liquid crystal box was heated at 120°C for 60 minutes, left at 23°C overnight, and used for the evaluation of liquid crystal orientation.

[0261] <Evaluation of Liquid Crystal Orientation>

[0262] The liquid crystal alignment in the liquid crystal cell produced according to the above steps was observed using a polarizing microscope (Nikon ECLIPSE E600 POL). A determination of "good" was made if the liquid crystal alignment was confirmed and no flow alignment was observed, while a determination of "poor" was made if no alignment was confirmed or if some flow alignment was observed. The results are shown in Table 1.

[0263] The liquid crystal cell produced according to the above steps was placed on a backlight for 5 days for aging. A voltage of 1V was then applied at 60°C for 60μs. The voltage after 500ms was measured, and the voltage retained was calculated as the voltage holding ratio. The voltage holding ratio was measured using a VHR-1 manufactured by Toyo Technica. The results are shown in Table 1. It should be noted that a higher voltage holding ratio indicates a better performance.

[0264] [Table 1]

[0265]

[0266] From the above results, it is understood that the liquid crystal aligning films obtained from the liquid crystal aligning agents (V-1) to (V-3) using the diamine (WA-1) exhibit liquid crystal orientation equivalent to that of the liquid crystal aligning film obtained from the liquid crystal aligning agent (W-1) using the diamine (C1).

[0267] On the other hand, it was found that the liquid crystal aligning films obtained from the liquid crystal aligning agents (V-1) to (V-3) using the diamine (WA-1) had better voltage retention than the liquid crystal aligning film obtained from the liquid crystal aligning agent (W-1) using the diamine (C1) even after being left on a backlight for 5 days.

[0268] Specifically, it is shown in the comparison between Examples 1 to 3 and Comparative Example 1 shown in Table 1.

[0269] As described above, by using a diamine having an imide ring skeleton and a nitrogen-containing heterocyclic ring, a liquid crystal alignment film having high liquid crystal orientation and high voltage retention after long-term irradiation with backlight can be obtained.

[0270] Industrial applicability

[0271] The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can be applied to various liquid crystal display elements represented by IPS drive mode and FFS drive mode liquid crystal display elements. Moreover, these display elements are not limited to liquid crystal displays for display purposes, and are also useful in dimming windows and optical shutters that control the transmission and interception of light.

[0272] Note that the entire contents of Japanese Patent Application No. 2020-074709 filed on April 20, 2020 including specification, claims, drawings, and abstract are incorporated herein by reference in their entirety and are incorporated as a disclosure of the specification of the present invention.

Claims

1. A liquid crystal alignment agent, characterized in that: Containing at least one polymer (A) selected from the group consisting of polyamic acid obtained using a tetracarboxylic acid derivative component and a diamine component containing a diamine represented by the following formula (1), and imidized polymers thereof, and an organic solvent, In the formula, X1 is any one of the following formulas (X1-1) to (X1-6), Ar represents a divalent nitrogen-containing heterocycle, the nitrogen-containing heterocycle is a five-membered aromatic heterocycle selected from a pyrrole ring, an imidazole ring, a pyrazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, and an isothiazole ring, or a six-membered aromatic heterocycle selected from a pyridine ring, a pyrimidine ring, a pyridazine ring, and a pyrazine ring, wherein any hydrogen atom of the nitrogen-containing heterocycle is optionally substituted with a monovalent substituent, and two Ars are optionally the same or different, 2. The liquid crystal aligning agent according to claim 1, wherein Ar in the formula (1) is a pyridine ring.

3. The liquid crystal aligning agent according to claim 1, wherein In the formula (1), X1 is the formula (X1-1) or (X1-2), and Ar is a pyridine ring.

4. The liquid crystal aligning agent according to claim 1 or 2, wherein The diamine represented by formula (1) is any one of the diamines represented by the following formulas (1-1) to (1-2), 5. The liquid crystal aligning agent according to claim 1 or 2, wherein 10 to 100 mol% of the diamine component is the diamine represented by formula (1). The liquid crystal aligning agent according to claim 1 or 2, wherein The diamine component further contains a diamine represented by the following formula (2) or formula (2i), 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, and Y 2i represents a divalent organic group represented by the following formula (O'), two R and Y 2i Each independently has the above definition, Ar represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring, two Ars are optionally the same or different, any hydrogen atom on the benzene ring, biphenyl structure, or naphthalene ring is optionally substituted by a monovalent substituent, p is an integer of 0 or 1, and Q2 represents -(CH2) n -, or the -(CH2) n -a group in which at least a portion of -CH2- is substituted by any of -O-, -C(=O)- or -O-C(=O)-, wherein the -(CH2) n - where n is an integer from 2 to 18, * represents a bond, Ar' represents a divalent benzene ring or a biphenyl structure, two Ar's are optionally the same or different, any hydrogen atom on the benzene ring or biphenyl structure is optionally substituted by a monovalent substituent, p' is an integer of 0 or 1, Q 2’ Indicates -(CH2) n -, or the -(CH2) n -a group in which at least a portion of -CH2- is substituted by any of -O-, -C(=O)- or -O-C(=O)-, wherein the -(CH2) n In -, n is an integer from 2 to 18, and * represents a bonding key.

7. The liquid crystal alignment agent according to claim 6, wherein The divalent organic group represented by the formula (O) is any one of the following formulas (o-1) to (o-16), In formula (o-14), two m are optionally the same or different, 8. The liquid crystal aligning agent according to claim 1 or 2, wherein The tetracarboxylic acid derivative component includes a compound represented by the following formula (3) or a derivative thereof, X represents a structure selected from the group consisting of the following (x-1) to (x-13), R 1 ~R 4 Each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, and R 5 and R 6 Each independently represents a hydrogen atom or a methyl group, j and k are integers of 0 or 1, A1 and A2 each independently represent a single bond, -O-, -CO-, -COO-, a phenylene group, a sulfonyl group, or an amide group, *1 is a bond to one acid anhydride group, *2 is a bond to another acid anhydride group, and two A2s are optionally the same or different.

9. The liquid crystal aligning agent according to claim 1 or 2, wherein The diamine component contains a diamine having at least one nitrogen-containing structure selected from the group consisting of a nitrogen-containing heterocycle, a secondary amino group, and a tertiary amino group, excluding the diamine represented by the formula (1).

10. The liquid crystal alignment agent according to claim 8, wherein The tetracarboxylic acid derivative component contains the compound represented by the formula (3) or a derivative thereof, wherein X is any one of (x-12) to (x-13).

11. The liquid crystal aligning agent according to claim 1 or 2, further comprising: At least one polymer (B) selected from the group consisting of polymers obtained using a tetracarboxylic acid derivative component and a diamine component not containing the diamine represented by the above formula (1), and imidized polymers thereof. 12 . A liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 1 . 13 . A liquid crystal display element comprising the liquid crystal alignment film according to claim 12 .

14. A method for producing a liquid crystal alignment film, comprising the following steps (1) to (3): Step (1): a step of applying the liquid crystal alignment agent according to any one of claims 1 to 11 onto a substrate; Step (2): a step of heating the applied liquid crystal alignment agent to obtain a film; Step (3): A step of irradiating the film obtained in step (2) with polarized ultraviolet rays.

15. The method for producing a liquid crystal alignment film according to claim 14, further comprising the following step (4): Step (4): a step of calcining the film obtained in step (3) at a temperature of 100° C. or higher and higher than that in step (2).

16. The method for producing a liquid crystal alignment film according to claim 14 or 15, wherein: The step (2) is a step of heating the liquid crystal aligning agent in a temperature range of 40 to 180° C. to obtain a film. 17 . A liquid crystal display element comprising a liquid crystal alignment film obtained by the method for producing a liquid crystal alignment film according to claim 14 .

18. A diamine represented by the following formula (1-1) or formula (1-2), 19 . A polyamic acid obtained from a diamine component, wherein the diamine component comprises the diamine represented by the formula (1-1) or (1-2) according to claim 18 .

20. A polyamic acid or an imidized polymer thereof, obtained by a polycondensation reaction of a diamine component comprising the diamine represented by the formula (1-1) or (1-2) according to claim 18 and a tetracarboxylic acid derivative component.

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