Novel diamine, polymer, liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element using the same

Abstract

The present invention provides a liquid crystal aligning agent which is capable of producing a liquid crystal alignment film by means of a photo-alignment method and which gives a liquid crystal alignment film having a good voltage retention rate even when a backlight is continuously illuminated for a long period of time.　The present invention provides a liquid crystal aligning agent characterized by containing an organic solvent and at least one type of 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 formula (1); and imidized products of the polymers. (The definitions of the substituent groups are as stated in the description.)

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] Conventionally, liquid crystal display devices have been widely used as display units for personal computers, smartphones, mobile phones, television receivers, and the like. A liquid crystal display device includes, for example, a liquid crystal layer sandwiched between an element substrate and a color filter substrate, a pixel electrode 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, a thin film transistor (TFT) for switching an electric signal supplied to the pixel electrode, and the like. As driving methods of liquid crystal molecules, vertical electric field methods such as TN method and VA method, and horizontal electric field methods such as IPS method and FFS (fringe field switching) method are known.

[0003] Currently, the most industrially widespread liquid crystal alignment film is produced by performing a so-called rubbing treatment in which the surface of a film made of polyamic acid and / or polyimide imidized therefrom formed on an electrode substrate is rubbed in one direction with a cloth such as cotton, nylon, or polyester. The rubbing treatment is a simple and industrially useful method with excellent productivity. However, with the high performance, high definition, and large size of liquid crystal display elements, various problems such as scratches on the surface of the alignment film generated by the rubbing treatment, dust generation, the influence of mechanical force and static electricity, and further non-uniformity within the alignment treatment surface have become apparent. As an alignment treatment method alternative to the rubbing treatment, an optical alignment method for imparting liquid crystal alignment ability by irradiating polarized radiation is known. As the optical alignment method, those using a photo-isomerization reaction, those using a photocrosslinking reaction, those using a photodegradation reaction, etc. have been proposed (see Non-Patent Document 1, Patent Document 1, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] [Non-Patent Document 1] "Liquid Crystal Photoalignment Film", Kido, Ichimura, Functional Materials, November 1997, Vol. 17, No. 11, pp. 13-22 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] In recent years, with the change in the usage form of liquid crystal display elements, there has been a growing demand for liquid crystal display elements that can withstand long-term use. In order to be able to be used for a long time, it is required that the characteristics do not change even when irradiated with light from the backlight unit for a long time. Therefore, there has been a growing demand for a liquid crystal alignment film whose display characteristics do not change significantly when irradiated with backlight light. In addition, there has been a problem that the liquid crystal alignment film produced by a process of applying and drying a polyimide-based liquid crystal aligning agent on a substrate, irradiating it with polarized ultraviolet light, and then baking it does not always have sufficient stability of liquid crystal alignment.

[0007] For the above reasons, the first object of the present invention is to provide a liquid crystal aligning agent capable of producing a liquid crystal alignment film by a photoalignment method and having a good voltage holding ratio even when continuously irradiated with backlight light for a long time, and further to provide a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film with little decrease in the voltage holding ratio even when irradiated with backlight light for a long time. The second object of the present invention is to provide a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film with good liquid crystal alignment even when produced by a process of irradiating with polarized ultraviolet light and then baking, in addition to the first object. [Means for Solving the Problems]

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a specific diamine, and have completed the present invention. Thus, the present invention is based on the above findings and has the following gist.

[0009] At least one polymer (A) selected from the group consisting of a polymer obtained by 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 a liquid crystal aligning agent characterized by containing an organic solvent.

Chemical formula

Chemical formula

Advantages of the Invention

[0010] The liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention by the photo-alignment method has a good voltage holding ratio even when irradiated with backlight light for a long time. Further, the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention by the photo-alignment method has good liquid crystal alignment properties even in the case of a liquid crystal alignment film produced by a process of irradiating with polarized ultraviolet rays and then baking. Although the mechanism by which the above effects of the present invention are obtained is not necessarily clear, it is considered to be partly due to the following. That is, since the polymer of the present invention has a cyclobutane ring and an imide ring structure in the molecule, photodegradation occurs even when polarized ultraviolet light is irradiated without thermal imidization. Therefore, it is considered that a liquid crystal alignment film produced by a process of irradiating polarized ultraviolet light and then baking also has good liquid crystal alignment properties. Furthermore, due to the heterocyclic structure, impurities in the liquid crystal layer are trapped, and it is considered that good voltage holding ratio is maintained even when backlight light is continuously irradiated for a long time.

Embodiments for Carrying Out the Invention

[0011] In the present specification, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Further, in the present specification, Boc represents a tert-butoxycarbonyl group. * represents a bond.

[0012] 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 a polymer obtained by 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 an imidized polymer thereof, and an organic solvent. Hereinafter, each condition will be described in detail.

[0013] <Polymer (A)> The polymer (A) used in the present invention is at least one polymer selected from the group consisting of a polymer obtained by using a tetracarboxylic acid derivative component and a diamine component containing a diamine represented by the following formula (1), and an imidized polymer thereof. Specific examples of such polymers include, for example, polyimide precursors having an imide precursor structure such as amic acid or amic acid ester, polyimides obtained by imidizing the polyimide precursors, polyureas having an imide structure, polyamides having an imide structure, and the like. From the viewpoint of use as a liquid crystal aligning agent, the polymer is preferably at least one selected from a polyimide precursor and a polyimide obtained by imidizing the polyimide precursor. Examples of the polyimide precursor include polyamic acid and polyamic acid ester. The polymer (A) may be used alone or in combination of two or more.

[0014] <Specific diamine> 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.

[0015]

Chemical formula

[0016]

Chemical formula

[0017] The divalent nitrogen atom-containing heterocyclic ring is a divalent group formed by removing any two hydrogen atoms of the nitrogen atom-containing heterocyclic ring. Examples of the nitrogen atom-containing heterocyclic ring include 5-membered aromatic heterocyclic rings such as pyrrole ring, imidazole ring, pyrazole ring, oxazole ring, isoxazole ring, thiazole ring, and isothiazole ring; 6-membered aromatic heterocyclic rings such as pyridine ring, pyrimidine ring, pyridazine ring, and pyrazine ring; and polycyclic aromatic heterocyclic rings such as indole ring and benzimidazole ring. From the viewpoint of enhancing the liquid crystal alignment property, Ar is preferably a divalent pyridine ring, pyrimidine ring, pyridazine ring, or pyrazine ring. Any hydrogen atom of the nitrogen atom-containing heterocyclic ring may be substituted with a monovalent substituent. Examples of the substituent include halogen atom, alkyl group having 1 to 10 carbon atoms, alkenyl group having 2 to 10 carbon atoms, alkoxy group having 1 to 10 carbon atoms, fluoroalkyl group having 1 to 10 carbon atoms, fluoroalkenyl group having 2 to 10 carbon atoms, fluoroalkoxy group having 1 to 10 carbon atoms, carboxyl group, hydroxy group, alkyloxycarbonyl group having 1 to 10 carbon atoms, cyano group, nitro group, and the like.

[0018] From the viewpoint of enhancing the liquid crystal alignment property, the tetravalent organic group represented by the above (g) preferably has any of the structures of the following formulas (X1-1) to (X1-6).

[0019]

Chemical formula

[0020] Preferred specific examples of the specific diamine include, but are not limited to, diamines represented by the following formulas (1-1) or (1-2). The diamines represented by the following formulas (1-1) or (1-2) are novel diamines.

[0021]

Chemical formula

[0022] <Diamine component> The diamine component for obtaining the polymer (A) contains at least one diamine represented by the above formula (1), and may consist of one type of diamine or may consist of two or more types of diamines. When the diamine component consists of two or more types of diamines, it may contain a diamine other than the diamine represented by the formula (1) together with the diamine represented by the formula (1). The proportion of the diamine represented by the formula (1) in the diamine component for obtaining the polymer (A) is preferably 5 to 100 mol%, more preferably 10 to 100 mol%, based on 1 mol of the diamine component.

[0023] As the diamine component for obtaining the polymer (A), it may contain a diamine represented by the following formula (2) or a diamine represented by the formula (2i) together with the diamine represented by the formula (1). The diamine represented by the following formula (2) or the diamine represented by the formula (2i) may be used alone or in combination of two or more.

[0024]

Chemical formula

[0025]

Chemical formula

[0026] Examples of the substituent on 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 hydroxy group, an alkyloxycarbonyl group having 1 to 10 carbon atoms, a cyano group, a nitro group, and the like.

[0027] From the viewpoint of enhancing the liquid crystal alignment property, the divalent organic group represented by the above formula (O) is preferably a divalent organic group represented by the following formulas (o-1) to (o-16).

[0028] [Chemical formula]

[0029] [Chemical formula] (In formula (o-14), two m's may be the same or different.)

[0030] [Chemical formula]

[0031] From the viewpoint of enhancing the liquid crystal alignment property, the divalent organic group represented by the above formula (O') is preferably a divalent organic group represented by the above formulas (o-7) to (o-16).

[0032] Preferable specific examples of the diamine represented by the above formula (2i) include compounds represented by the following formulas (2i-1) to (2i-5).

[0033]

Chemical formula

[0034] From the viewpoint of obtaining the effects of the present invention, the total proportion of the diamine represented by the formula (2) and the diamine represented by the 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% with respect to 1 mol of the diamine component. In this case, the upper limit of the content of the diamine represented by the formula (1) is preferably 99 mol% or less, and more preferably 95 mol% or less.

[0035] As the diamine component for obtaining the polymer (A), other diamines other than the diamine represented by the above formula (1), the diamines represented by the above formulas (2) and (2i) may be used. Examples of other diamines include diamines having 6 to 30 carbon atoms having a group “-N(D)-(D represents a carbamate-based protecting group)” in the molecule; 4,4'-diaminoazobenzene and the following formula (d T -1) to (d TDiamines having a photo-orienting group such as the diamine represented by -3); diamines represented by the following formulas (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, 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 other aromatic diamines, and the diamines used in the polymer (B) described later. As the diamines used in the polymer (B) described later, among others, diamines having at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocyclic ring, a secondary amino group and a tertiary amino group (hereinafter also referred to as a specific nitrogen atom-containing structure) (however, excluding the above specific diamines) can be preferably used. Examples of the carbamate-based protecting group include a tert-butoxycarbonyl group and a 9-fluorenylmethoxycarbonyl group.

[0036]

Chemical formula

[0037]

Chemical formula

[0038] Examples of the diamine having 6 to 30 carbon atoms and having the group "-N(D)- (where D represents a carbamate-based protecting group)" in the molecule include compounds represented by the following formulas (5-1) to (5-10).

[0039]

Chemical formula

[0040] From the viewpoint of obtaining the effects of the present invention, the proportion 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% with respect to 1 mol of the diamine component.

[0041] (Tetracarboxylic acid derivative component) When producing the above polymer (A), the tetracarboxylic acid derivative component to be reacted with the diamine component can be not only a tetracarboxylic dianhydride, but also derivatives of tetracarboxylic dianhydrides such as tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters, or tetracarboxylic acid dialkyl ester dihalides. The tetracarboxylic acid derivative component may be used alone with one kind of tetracarboxylic dianhydride or its derivative, or may be used in combination of two or more kinds.

[0042] Examples of the above tetracarboxylic dianhydride or its derivative include aromatic, acyclic aliphatic or alicyclic tetracarboxylic dianhydrides, or derivatives thereof. 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. The 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 only of a chain hydrocarbon structure, and a part thereof may have an alicyclic structure or an aromatic ring structure.

[0043] The alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an alicyclic structure. However, none of these four carboxyl groups are bonded to an aromatic ring. Also, it is not necessary to be composed only of an alicyclic structure, and a part thereof may have a chain hydrocarbon structure or an aromatic ring structure.

[0044] 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.

[0045]

Chemical formula

[0046]

Chemical formula

[0047] More preferable specific examples of the above formula (x-1) include the following formulas (X1-1) to (X1-6).

[0048]

Chemical formula

[0049] Preferable specific examples of the above formulas (x-12) and (x-13) include the following formulas (x-14) to (x-29).

[0050]

Chemical formula

[0051] [Chem.]

[0052] Preferred specific examples of the tetracarboxylic dianhydride represented by the above formula (3) or its derivative include those in which X is selected from the above formulas (x-1) to (x-8), (x-10) to (x-13). The above X may further be selected from any one of (x-12) to (x-13).

[0053] When two or more types of the polymer (A) are used, the tetracarboxylic acid derivative components for obtaining each polymer may be different. For example, the polymer (A) may be a mixture of a polymer (A1) obtained from a tetracarboxylic acid derivative component containing 50 mol% or more of any one of an acyclic tetracarboxylic dianhydride, an alicyclic tetracarboxylic acid derivative, or a derivative thereof, and a polymer (A2) obtained from a tetracarboxylic acid derivative component containing 50 mol% or more of any one of an aromatic tetracarboxylic acid derivative or a derivative thereof. The proportion of the tetracarboxylic dianhydride represented by the formula (3) and its derivative in the tetracarboxylic acid derivative component for obtaining the polymer (A) is preferably 1 mol% or more, more preferably 5 mol% or more, and still more preferably 10 mol% or more with respect to 1 mol of the tetracarboxylic acid derivative component. The tetracarboxylic acid derivative component used in the production of the polymer (A) may contain a tetracarboxylic dianhydride or its derivative other than the above formula (3) (hereinafter, other tetracarboxylic dianhydride or its derivative). Examples of other tetracarboxylic dianhydride or its derivative include a tetracarboxylic dianhydride or its derivative 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.

[0054] [Chem.] (XT represents a structure selected from the group consisting of the following (t-1) to (t-26).)

[0055]

Chemical formula

[0056]

Chemical formula

[0057]

Chemical formula

[0058]

Chemical formula

[0059] <Polymer (B)> From the viewpoint of reducing the afterimage derived from residual DC, the liquid crystal aligning agent of the present invention may contain a polymer other than the polymer (A). Specific examples of such a polymer include at least one polymer selected from the group consisting of a polymer obtained by using a tetracarboxylic acid derivative component and a diamine component not containing the above specific diamine, and an imidized polymer thereof. Specific examples of such a polymer include the above polyimide precursor or a polyimide which is an imidized polymer thereof. From the viewpoint of use as a liquid crystal aligning agent, it is preferably at least one selected from a polyimide precursor and a polyimide which is an imidized polymer thereof. The polymer (B) may be used alone or in combination of two or more kinds.

[0060] Examples of the tetracarboxylic acid derivative component for obtaining the polymer (B) include acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, or derivatives thereof. Specific examples of the acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aromatic tetracarboxylic dianhydrides include the tetracarboxylic dianhydrides exemplified in the polymer (A). Among them, as the preferred tetracarboxylic acid derivative component, the compound represented by the above formula (3) or its derivative is preferred. The above tetracarboxylic acid derivative component may be used alone or in combination of two or more kinds.

[0061] In the polymer (B), more preferred specific examples of the tetracarboxylic dianhydride represented by the above formula (3) or its derivative include the tetracarboxylic dianhydride represented by the formula (3) in which X is selected from the above formulas (x-1) to (x-8), (x-10) to (x-13) or its derivative.

[0062] As the diamine component for obtaining the polymer (B), the diamines exemplified for the above polymer (A) (however, excluding the above specific diamines); at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocyclic ring, a secondary amino group, and a tertiary amino group (hereinafter, also referred to as a specific nitrogen atom-containing structure).Diamines having (provided that the 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, and diamines having a carboxy group such as diamine compounds represented by the following formulas (3b-1) to (3b-4); 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 such as diamines represented by the above formulas (h-1) to (h-3); diamines having an amide bond such as diamines represented by the above formulas (h-4) to (h-6); diamines having a photopolymerizable group at the terminal such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline; diamines having a steroid skeleton such as cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate, lanostanyl 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 the following formulas (Ox-1) to (Ox-2); diamines in which two amino groups are bonded to a group represented by any of the formulas (Y-1) to (Y-167) described in International Publication No. 2018 / 117239. The above diamine component may be used alone or in combination of two or more.

[0063] [Chemical formula] (In formula (3b-1), A 1 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-. 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 from 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-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)- or -N(CH3)CO-, and m6 represents an integer from 1 to 4.)

[0064] [Chemical formula] (X v1 ~ X v4 , X p1 ~ X p2 each independently represents -(CH2) a - (where a is an integer from 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- (where m is an integer from 1 to 6). R v1 ~ R v4 , R 1a ~ R 1bEach 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), the two k's may be the same or different.)

[0065]

Chemical formula

[0066] Examples of the nitrogen atom-containing heterocyclic ring that the diamine having the above specific nitrogen atom-containing structure may have include pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, isoquinoline, naphthyridine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, hexamethyleneimine, etc. Among them, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole or acridine is preferable.)

[0067] The secondary amino group and tertiary amino group that the diamine having the above specific nitrogen atom-containing structure may have are represented by, for example, the following formula (n).

[0068]

Chemical formula

[0069] Examples of the monovalent hydrocarbon group of R in the above formula (n) include alkyl groups such as methyl group, ethyl group, and propyl group; cycloalkyl groups such as cyclohexyl group; aryl groups such as phenyl group and methylphenyl group, etc. R is preferably a hydrogen atom or a methyl group.)

[0070] Specific examples of the diamine having a specific nitrogen atom-containing structure include, 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 formulas (Dp-1) to (Dp-9), and compounds represented by the following formulas (z-1) to (z-18).

[0071] [Chemical formula]

[0072] [Chemical formula]

[0073] [Chemical formula]

[0074] From the viewpoint of having less afterimage derived 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 atom-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 diamine compounds having a carboxy group such as the diamines represented by the above formulas (3b-1) to (3b-4) or diamines having the above urea bond (these are also collectively referred to as diamine (b)).

[0075] The proportion of 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.

[0076] From the viewpoint of having less residual image derived from residual DC, the content ratio of polymer (A) and polymer (B) may be 10 / 90 to 90 / 10, may be 20 / 80 to 90 / 10, or may be 20 / 80 to 80 / 20 in terms of the mass ratio of [polymer (A)] / [polymer (B)].

[0077] The ratio of the tetracarboxylic dianhydride represented by the above formula (3) and its derivative in the tetracarboxylic dianhydride component for obtaining polymer (B) is preferably 1 to 100 mol%, more preferably 5 to 70 mol%, and still more preferably 10 to 50 mol% with respect to 1 mol of the tetracarboxylic acid derivative component. <Method for producing polymer (A) and polymer (B)>

[0078] [Polyimide precursor] The polyamic acid which is the polyimide precursor used in the present invention is carried out, for example, by reacting the above diamine component and the above tetracarboxylic acid derivative component in a solvent (polycondensation). When the above tetracarboxylic acid derivative component contains a tetracarboxylic dianhydride, a polymer containing an amic acid structure is obtained. The solvent is not particularly limited as long as the produced polymer is soluble therein. Specific examples of the above solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone. Further, when the solvent solubility of the polymer is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a solvent represented by the following formulas [D-1] to [D-3] can be used.

[0079] [Chemical formula] (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 3represents an alkyl group having 1 to 4 carbon atoms.).

[0080] These solvents may be used alone or in combination. Furthermore, even if it is a solvent that does not dissolve the polymer, it may be used by mixing with the above solvent as long as the produced polymer does not precipitate. When reacting the diamine component and the tetracarboxylic acid derivative component in a solvent, the reaction can be carried out at any concentration, but preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration at the initial stage of the reaction, and then the solvent can be added. 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. Similar to a normal polycondensation reaction, the closer this molar ratio is to 1.0, the larger the molecular weights of the produced polymers (A) and (B) become.

[0081] The polyamic acid ester (polymer containing an amic acid ester structure), which is a polyimide precursor used in the present invention, can be obtained, for example, by [I] a method of reacting a polymer containing an amic acid structure obtained by the above 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.

[0082] [Imidized polymer] The imidized polymer contained in the liquid crystal aligning agent of the present invention is obtained by ring-closing a polymer containing the above amic acid structure or amic acid ester structure. In the imidized polymer, the ring-closing rate (also referred to as the imidization rate) of the functional group of the amic acid group or amic acid ester does not necessarily have to be 100%, and can be arbitrarily adjusted according to the use and purpose.

[0083] As a method for imidizing a polymer containing the above amic acid structure or amic acid ester structure to obtain an imidized polymer, there are thermal imidization in which a solution of the polymer containing the above amic acid structure or amic acid ester structure is directly heated, or catalytic imidization in which a catalyst is added to a solution of the polymer containing the above amic acid structure or amic acid ester structure. The temperature in the case of thermal imidization is preferably 100 to 400 °C, more preferably 120 to 250 °C, and it is preferable to carry out the process while removing the water generated by the imidization reaction out of the system.

[0084] Catalytic imidization can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polymer and stirring preferably at -20 to 250 °C, more preferably at 0 to 180 °C. The amount of the basic catalyst is preferably 0.5 to 30 molar times, more preferably 2 to 20 molar times, of the amic acid group, and the amount of the acid anhydride is preferably 1 to 50 molar times, more preferably 3 to 30 molar times, of the amic acid group. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, etc. Among them, pyridine is preferable because it has an appropriate basicity to promote the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. Among them, acetic anhydride is preferable because purification after the reaction becomes easy when it is used. The imidization rate by catalytic imidization can be controlled by adjusting the catalyst amount, reaction temperature, and reaction time.

[0085] When recovering the imidized polymer produced from the reaction solution for catalyst imidization, the reaction solution may be poured into a solvent for precipitation. Examples of the solvent used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, water, etc. The polymer precipitated by pouring into the solvent can be recovered by filtration and then dried at normal pressure or reduced pressure, at room temperature or by heating. Also, if the operation of redissolving the polymer recovered by precipitation in a solvent and recovering it by reprecipitation is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the solvent at this time include alcohols, ketones, hydrocarbons, etc. Using three or more solvents selected from these is preferable because the purification efficiency is further improved.

[0086] <Solution viscosity and molecular weight of the polymer> The polymers (A) and (B) used in the present invention preferably have a solution viscosity of, for example, 10 to 1000 mPa·s when made into a solution with a concentration of 10 to 15% by weight from the viewpoint of workability, but are not particularly limited. The solution viscosity (mPa·s) of the above polymer is a value measured at 25°C using an E-type rotational viscometer for a polymer solution with a concentration of 10 to 15% by mass prepared using a good solvent (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) of the polymer.

[0087] The weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of the above polymers (A) and (B) is preferably 1,000 to 500,000, more preferably 2,000 to 500,000. Also, the molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 15 or less, more preferably 10 or less. Being in such a molecular weight range can ensure good alignment and stability of the liquid crystal display element.

[0088] <Polymer obtained from a diamine component containing a diamine represented by formula (1-1) or (1-2)> Examples of the polymer 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 ester, polyimides obtained by imidizing the polyimide precursors, polyureas having an imide structure, and polyamides having an imide structure. The above polymer is preferably a polymer obtained by polycondensation reaction of a diamine component containing a diamine represented by the above 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 polycondensation reaction of a diamine component containing a diamine represented by the above formula (1-1) or (1-2) and a tetracarboxylic acid derivative component, or a polyimide obtained by imidizing the polyimide precursor. Note that the polycondensation reaction between the diamine component and the tetracarboxylic acid derivative component is as described in the above <Production method of polymer (A) and polymer (B)>.

[0089] <Liquid crystal aligning agent> The liquid crystal aligning agent of the present invention contains polymer (A) and, if necessary, polymer (B). The liquid crystal aligning agent of the present invention may contain other polymers in addition to polymer (A) and polymer (B). Examples of the types of other polymers include polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or its derivative, poly(styrene-phenylmaleimide) derivative, poly(meth)acrylate, and the like.

[0090] The liquid crystal aligning agent is used to produce a liquid crystal alignment film and takes the form of a coating solution from the viewpoint of forming a uniform thin film. Also in the liquid crystal aligning agent of the present invention, it is preferably a coating solution containing the above-described polymer component and an organic solvent. At that time, the concentration of the polymer component in the liquid crystal aligning agent can be appropriately changed according to the setting of the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, 1% by mass or more is preferable, and from the viewpoint of the storage stability of the solution, 10% by mass or less is preferable. A particularly preferable concentration of the polymer component is 2 to 8% by mass. 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 with respect 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, and more preferably 20 to 80% by mass.

[0091] The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as the polymer component is uniformly dissolved. 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-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, 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 collectively also referred to as "good solvents"), and the like. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, or γ-butyrolactone is preferable. The content of the good solvent is preferably 20 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass of the total solvent contained in the liquid crystal aligning agent.

[0092] In addition, as the organic solvent contained in the liquid crystal aligning agent, it is preferable to use a mixed solvent in which a solvent (also referred to as a poor solvent) that improves the coatability and the surface smoothness of the coating film when applying the liquid crystal aligning agent is used in combination with the above solvent. Specific examples of the organic solvent to be used in combination are described below, but are not limited thereto.

[0093] 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 monoisoamyl 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, 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), and the like can be mentioned.

[0094] 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 is preferable.

[0095] Preferable combinations of the good solvent and the 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 and γ-butyrolactone and propylene glycol monobutyl ether and diisobutyl ketone, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisopropyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisobutyl carbinol, N-methyl-2-pyrrolidone and γ-butyrolactone and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone and 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 solvent contained in the liquid crystal aligning agent. The type and content of the poor solvent are appropriately selected according to the coating apparatus, coating conditions, coating environment, etc. of the liquid crystal aligning agent.

[0096] The liquid crystal aligning agent of the present invention may additionally contain components other than the polymer component and the organic solvent (hereinafter also referred to as additive components). Examples of such additive components include adhesion aids for enhancing the adhesion between the liquid crystal alignment film and the substrate and between the liquid crystal alignment film and the sealing material, compounds for enhancing the strength of the liquid crystal alignment film (hereinafter also referred to as crosslinkable compounds), dielectrics and conductive substances for adjusting the dielectric constant and electrical resistance of the liquid crystal alignment film, and the like.

[0097] As the above crosslinkable compound, from the viewpoint of exhibiting good resistance to AC residual images and having a high improvement in film strength, a compound having at least one group selected from the group consisting of an oxiranyl group, an oxetanyl group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Meldrum's acid structure, a cyclocarbonate group, a group represented by the following formula (d), and a group represented by the following formula (d1), or a compound selected from compounds represented by the following formula (e) (hereinafter, these are also collectively referred to as compound (C)) may be used.

[0098]

Chemical formula

[0099] Specific examples of the compound having an oxiranyl group include compounds having two or more oxiranyl groups such as the compounds described in paragraph

[0037] of JP-A-10-338880 and compounds having a triazine ring as a skeleton described in International Publication No. 2017 / 170483. Among these, nitrogen atom-containing compounds such as N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, and compounds represented by the following formulas (r-1) to (r-3) may also be used.

[0100] [Chemical formula]

[0101] Specific examples of the compound having an oxetanyl group include compounds having two or more oxetanyl groups described in paragraphs

[0170] to

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

[0102] Specific examples of the compound having a protected isocyanate group include compounds having two or more protected isocyanate groups described in paragraphs

[0046] to

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

[0119] to

[0120] of International Publication No. 2015 / 141598, and compounds represented by the following formulas (bi-1) to (bi-3) may also be used.

[0103] [Chemical formula]

[0104] 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.

[0105] Specific examples of the compound having a group containing an oxazoline ring structure include compounds containing two or more oxazoline structures described in paragraph

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

[0106] Specific examples of the compound having a group containing a Meldrum's acid structure include compounds having two or more Meldrum's acid structures described in International Publication No. 2012 / 091088.

[0107] Specific examples of the compound having a cyclocarbonate group include the compounds described in International Publication No. 2011 / 155577.

[0108] Examples of the alkyl group having 1 to 3 carbon atoms for R2 and R3 in the group represented by the above formula (d) include a methyl group, an ethyl group, a propyl group and the like.

[0109] Specific examples of the compound having the group represented by the above formula (d) include compounds having two or more groups represented by the above formula (d) described in International Publication No. 2015 / 072554 and paragraph

[0058] of JP-A-2016-118753, compounds described in JP-A-2016-200798, and the like, and may also be compounds represented by the following formulas (hd-1) to (hd-8).

[0110]

Chemical formula

[0111] Specific examples of the compound having the group represented by the above (d1) include the compounds described in International Publication No. 2019 / 142927, and more preferably may be compounds represented by the following formulas (hd1-1) to (hd1-4).

Chemical formula

[0112] Examples of the (m + n)-valent organic group having an aromatic ring in A of the above formula (e) include (m + n)-valent aromatic hydrocarbon groups having 6 to 30 carbon atoms, (m + n)-valent organic groups in which an aromatic hydrocarbon group having 6 to 30 carbon atoms is bonded directly or via a linking group, and (m + n)-valent groups having an aromatic heterocyclic ring. Examples of the above aromatic hydrocarbon include benzene, naphthalene, etc. Examples of the aromatic heterocyclic ring include pyrrole ring, imidazole ring, pyrazole ring, pyridine ring, pyrimidine ring, quinoline ring, isoquinoline ring, carbazole ring, pyridazine ring, pyrazine ring, benzimidazole ring, indole ring, quinoxaline ring, acridine ring, etc. Examples of the above linking group include alkylene groups having 1 to 10 carbon atoms, -NR- (R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), alkylene groups having 1 to 10 carbon atoms having a fluorine atom, or a group obtained by removing one hydrogen atom from the above alkylene group, divalent or trivalent cyclohexane rings, etc. Incidentally, 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 the compound having the group represented by the above formula (e) include the compounds described in International Publication No. 2010 / 074269 and the compounds represented by the following formulas (e-1) to (e-10).

[0113]

Chemical formula

[0114] The above compounds are an example of crosslinkable compounds and are not limited thereto. For example, components other than the above disclosed on pages 53

[0105] to 55

[0116] of International Publication No. 2015 / 060357 can be mentioned. Also, two or more crosslinkable compounds may be combined.

[0115] In the liquid crystal aligning agent of the present invention, the content of the crosslinkable compound is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent, and more preferably 1 to 15 parts by mass from the viewpoint that the crosslinking reaction proceeds and good resistance to AC residual images is exhibited.

[0116] Examples of the above adhesion aids 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-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,Silane coupling agents such as (4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, etc. are included. When using a silane coupling agent, from the viewpoint of exhibiting good resistance to AC afterimages, it is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, based on 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.,

[0117] <Method for manufacturing liquid crystal alignment film> The method for manufacturing a liquid crystal alignment film using the liquid crystal aligning agent of the present invention includes a step of applying the above liquid crystal aligning agent (step (1)), a step of baking the applied liquid crystal aligning agent (step (2)), a step of irradiating the film obtained in step (2) with polarized ultraviolet rays (step (3)), and a step of baking the film obtained in step (3) at 100°C or higher and at a temperature higher than that in step (2) (step (4)) in sequence. By including the step of baking the film obtained in step (3) at 100°C or higher and at a temperature higher than that in step (2) (step (4)), the effect that the liquid crystal alignment film is reoriented along the alignment direction axis generated by the irradiation with polarized ultraviolet rays and the liquid crystal alignment property is exhibited can be obtained.

[0118] <Step (1)> The substrate on which the liquid crystal aligning agent used in the present invention is applied is not particularly limited as long as it has high transparency, and glass substrates, silicon nitride substrates, plastic substrates such as acrylic substrates and polycarbonate substrates can also be used. In that case, it is preferable to use a substrate on which an ITO electrode or the like for driving the liquid crystal is formed from the viewpoint of simplifying the process. In a reflective liquid crystal display element, an opaque material such as a silicon wafer can be used as long as it is only on one side of the substrate, and a material that reflects light such as aluminum can also be used for the electrode in this case.

[0119] The method of applying the liquid crystal aligning agent is not particularly limited, but industrially, methods such as screen printing, offset printing, flexographic printing or inkjet printing are generally used. Other coating methods include dip coating, roll coating, slit coating, spinner coating or spray coating, etc., and these may be used according to the purpose.

[0120] <Step (2)> Step (2) is a step of baking the liquid crystal aligning agent applied on the substrate to form a film. After applying the liquid crystal aligning agent on the substrate, the solvent can be evaporated or the thermal imidization of the amic acid or amic acid ester in the polymer can be carried out by heating means such as a hot plate, a heat circulation type oven or an IR (infrared) type oven. For the drying and baking steps after applying the liquid crystal aligning agent of the present invention, any temperature and time can be selected, and they may be carried out multiple times. The baking temperature of the liquid crystal aligning agent can be, for example, 40 to 150 °C. From the viewpoint of shortening the process, it may be carried out at 40 to 120 °C. The baking time is not particularly limited, but examples include 1 to 10 minutes or 1 to 5 minutes. When performing the thermal imidization of the amic acid or amic acid ester in the polymer, after the above baking step, a baking step can be carried out in a temperature range of, for example, 190 to 250 °C, or 200 to 240 °C. The baking time is not particularly limited, but examples include a baking time of 5 to 40 minutes or 5 to 30 minutes.

[0121] <Step (3)> Step (3) is a step of irradiating the film obtained in step (2) with polarized ultraviolet light. As the wavelength of the ultraviolet light, 200 to 400 nm is preferable, and among them, ultraviolet light having a wavelength of 200 to 300 nm is more preferable. In order to improve the liquid crystal alignment property, ultraviolet light may be irradiated while heating the substrate coated with the liquid crystal alignment film at 50 to 250 °C. Further, the irradiation dose of the above radiation is preferably 1 to 10,000 mJ / cm 2 is preferable, and 100 to 5,000 mJ / cm 2 is more preferable. The liquid crystal alignment film produced in this way can stably align liquid crystal molecules in a certain direction.

[0122] The higher the extinction ratio of the polarized ultraviolet light, the higher the anisotropy that can be imparted, which is preferable. Specifically, the extinction ratio of the linearly polarized ultraviolet light is preferably 10:1 or more, and more preferably 20:1 or more.

[0123] <Step (4)> Step (4) is a step of firing the film obtained in step (3) at 100 °C or higher and at a temperature higher than that in step (2). The firing temperature is not particularly limited as long as it is 100 °C or higher and higher than the firing temperature in step (2), but 150 to 300 °C is preferable, 150 to 250 °C is more preferable, and 200 to 250 °C is even more preferable. Further, the above firing temperature is preferably 100 °C or higher and 70 °C or more higher than the firing temperature in step (2), more preferably 100 °C or higher and 100 °C or more higher than the firing temperature in step (2), and even more preferably 100 °C or higher and 150 °C or more higher than the firing temperature in step (2). The firing time is preferably 5 to 120 minutes, more preferably 5 to 60 minutes, and even more preferably 5 to 30 minutes.

[0124] If the thickness of the liquid crystal alignment film after firing is too thin, the reliability of the liquid crystal display element may decrease, so 5 to 300 nm is preferable, and 10 to 200 nm is more preferable.

[0125] Furthermore, after performing either step (3) or (4) above, the obtained liquid crystal alignment film can also be subjected to a contact treatment using water or a solvent.

[0126] The solvent used for the above contact treatment is not particularly limited as long as it can dissolve the decomposition products generated from the liquid crystal alignment film by 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, or cyclohexyl acetate. Among them, from the viewpoints of versatility and solvent safety, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate is preferred. More preferably, water, 1-methoxy-2-propanol, or ethyl lactate. The solvent may be used alone or in combination of two or more.

[0127] Examples of the above contact treatment, that is, the method of treating the liquid crystal alignment film irradiated with polarized ultraviolet rays with water or a solvent include immersion treatment and spray treatment (also referred to as spray treatment). The treatment time in these treatments is preferably 10 seconds to 1 hour from the viewpoint of efficiently dissolving the decomposition products generated from the liquid crystal alignment film by ultraviolet rays. Among them, it is preferable to perform an immersion treatment for 1 to 30 minutes. Also, the solvent during the above contact treatment may be at room temperature or heated, but preferably it is 10 to 80°C, and more preferably 20 to 50°C. In addition, from the viewpoint of the solubility of the decomposition products, ultrasonic treatment or the like may be performed as necessary.

[0128] After the above contact treatment, it is preferable to perform rinsing (also referred to as rinsing) with a low-boiling solvent such as water, methanol, ethanol, 2-propanol, acetone or methyl ethyl ketone, or baking of the liquid crystal alignment film. At this time, either one of rinsing and baking may be performed, or both may be performed. The baking temperature is preferably 150 to 300 °C. Among them, 180 to 250 °C is preferable. More preferably, it is 200 to 230 °C. Also, the baking time is preferably 10 seconds to 30 minutes. Among them, 1 to 10 minutes is preferable.

[0129] The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for a horizontal electric field type liquid crystal display element such as an IPS system or an FFS system, and is particularly useful as a liquid crystal alignment film for an FFS system liquid crystal display element. The liquid crystal display element is obtained by preparing a substrate with a liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention, then manufacturing a liquid crystal cell by a known method, and using the liquid crystal cell.

[0130] As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. Note that an active matrix structure liquid crystal display element in which switching elements such as TFTs (Thin Film Transistors) are provided in each pixel portion constituting the image display may also be used.

[0131] Specifically, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segment electrode is provided on the other substrate. These electrodes can be, for example, ITO electrodes, and are patterned so that a desired image display can be performed. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film can be, for example, a SiO2-TiO2 film formed by the sol-gel method.

[0132] Next, a liquid crystal alignment film is formed on each substrate. One substrate is overlaid on the other substrate such that the liquid crystal alignment film surfaces face each other, and the periphery is adhered with a sealant. To control the substrate gap, spacers are usually mixed into the sealant. Also, it is preferable to scatter spacers for controlling the substrate gap in the in-plane portion where no sealant is provided. An opening through which liquid crystal can be filled from the outside is 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 this opening is sealed with an adhesive. For the injection, a vacuum injection method may be used, or a method utilizing capillary action in the atmosphere may be used. As the liquid crystal material, either a positive-type liquid crystal material or a negative-type liquid crystal material may be used. Next, polarizing plates are installed. Specifically, a pair of polarizing plates are attached to the surfaces of the two substrates on the side opposite to the liquid crystal layer.

[0133] By using the manufacturing method of the present invention, afterimages caused by long-term AC driving occurring in liquid crystal display elements of the IPS driving method or the FFS driving method can be suppressed. Also, in step (2), after removing the organic solvent in the temperature range of 40 to 150 °C and then performing step (3), a liquid crystal alignment film can be obtained with a smaller number of steps than before. The liquid crystal aligning agent of the present invention can be particularly preferably used in a method for manufacturing a liquid crystal alignment film including a step of performing step (3) after removing the organic solvent in the temperature range of 40 to 150 °C in step (2).

Examples

[0134] Examples are given below to explain the present invention more specifically, but the present invention is not limited thereto. The abbreviations of the compounds and the measurement methods of each property in the following are as follows. (Specific diamine) WA-1: A compound represented by the following formula [WA-1]

[0135]

Chemical formula

[0136]

Chemical formula

[0137]

Chemical formula

[0138] < 1 <Measurement of 1H - NMR> Apparatus: Fourier transform superconducting nuclear magnetic resonance apparatus (FT - NMR) “AVANCE III” (manufactured by BRUKER), 500 MHz. Solvent: Deuterated dimethyl sulfoxide ([D6] - DMSO). Standard substance: Tetramethylsilane (TMS). <Measurement of molecular weight> The molecular weight of the polymer was measured as follows using a normal - temperature gel permeation chromatography (GPC) apparatus (GPC - 101) (manufactured by Showa Denko K.K.) and columns (in series of KD - 803 and KD - 805) (manufactured by Showa Denko K.K.). Column temperature: 50 °C Eluent: N,N - Dimethylformamide (as additives, lithium bromide monohydrate (LiBr·H2O) is 30 mmol / L (liter), ortho - phosphoric acid (anhydrous crystal) is 30 mmol / L, tetrahydrofuran (THF) is 10 mL / L) Flow rate: 1.0 ml / min Standard samples for calibration curve preparation: TSK standard polyethylene oxide (molecular weights: approximately 900,000, 150,000, 100,000, and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weights: approximately 12,000, 4,000, and 1,000) (manufactured by Polymer Laboratories). <Viscosity measurement> 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 cone rotor TE-1 (1°34’, R24).

[0139] [Synthesis of compound (WA-1)] <Monomer synthesis example 1> Diamine (WA-1) was synthesized according to the following route.

[0140] (Synthesis of WA-1-1) [Chemical formula]

[0141] To 2,5-diaminopyridine hydrochloride (18.6 g, 102 mmol), water (92.8 g) was added and dissolved, and then methanol (93.2 g) was added to make a mixed solution. To this, triethylamine (25.9 g, 255 mmol) and Boc2O (21.2 g, 102 mmol) were added to carry out the reaction. After completion of the reaction, liquid separation was performed with chloroform (748 g) and water (500 g) to separate the organic layer and the aqueous layer. The obtained organic layer was washed twice with water (300 g) to obtain organic layer 1. The obtained aqueous layer was extracted twice with chloroform (374 g) to obtain organic layer 2. After mixing organic layers 1 and 2, they were concentrated and dried to obtain WA-1-1 (yield: 16.5 g, 79.1 mmol, yield rate: 77.6%).

[0142] (Synthesis of WA-1-2) [Chemical formula]

[0143] To WA-1-1 (15.2 g, 72.4 mmol), NMP (152 g) and the tetracarboxylic dianhydride represented by (B1) (8.11 g, 36.2 mmol) were added, and the mixture was stirred at 60 °C for 16 hours. Then, pyridine (17.2 g, 217 mmol) and acetic anhydride (11.2 g, 109 mmol) were added, NMP (80 g) was further added, and the mixture was stirred at 65 °C for 18 hours. Then, the mixture was 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 rate: 64.6%).

[0144] (Synthesis of WA-1-3) [Chemical formula]

[0145] To WA-1-2 (14.2 g, 23.4 mmol), ethyl acetate (143 g) was added, and after the temperature was raised to 60 °C, 36% hydrochloric acid (3.86 g) was added. After heating for 54 hours, concentrated hydrochloric acid (1.18 g) was further added, and heating was continued for 48 hours to complete 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 rate: 92.3%).

[0146] (Synthesis of WA-1) [Chemical formula]

[0147] To WA-1-3 (11.1 g, 20.1 mmol), water (66.9 g) and triethylamine (12.0 g, 119 mmol) were added, and the mixture was stirred at room temperature for 19 hours. Then, 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 rate: 48.7%). As shown below 1 From the results of 1H-NMR, it was confirmed that this solid was WA-1. 1H-NMR (500 MHz, [D6]-DMSO): δ 7.90 (d, 2H), 7.09 - 7.08 (m, 4H), 5.68 - 5.64 (br, 4H), 3.40 (s, 2H), 1.38 (s, 6H)

[0148] (Polymer Synthesis Example 1) B1 (0.784 g, 4.00 mmol) was stirred in NMP (5.80 g) at room temperature for 30 minutes, 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 the mixture was 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 this polymer was 6,320, and the weight average molecular weight was 20,400.

[0149] (Polymer Synthesis Example 2) B1 (0.784 g, 4.00 mmol) was stirred in NMP (5.80 g) at room temperature for 30 minutes, 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 the mixture was reacted at room temperature for 15 hours to obtain a polymer solution [2] with a resin solid content concentration of 12% by mass (viscosity: 142 mPa·s). The number average molecular weight of this polymer was 10,300, and the weight average molecular weight was 39,100. (Polymer Synthesis Example 3) B2 (2.283 g, 7.76 mmol) was stirred in NMP (22.45 g) at room temperature for 30 minutes, then WA-1 (0.975 g, 2.40 mmol), A3 (1.116 g, 5.60 mmol), and NMP (9.62 g) were added, and 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 this polymer was 11,500, and the weight average molecular weight was 41,300. (Polymer Synthesis Example 4) B2 (2.283 g, 7.76 mmol) was stirred in NMP (22.43 g) at room temperature for 30 minutes, then C1 (0.971 g, 2.40 mmol), A3 (1.116 g, 5.60 mmol), and NMP (9.61 g) were added, and the mixture was reacted at 50 °C for 15 hours to obtain a polymer solution [4] with a resin solid content concentration of 12% by mass (viscosity: 442 mPa·s). The number average molecular weight of this polymer was 10,500, and the weight average molecular weight was 40,300.

[0150] <Preparation of Liquid Crystal Alignment Agent> (Example 1) To the polymer solution [1] (4.17 g) obtained in Polymer Synthesis Example 1, NMP (0.833 g), GBL (3.00 g), and BCS (2.00 g) were added, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (V-1). No abnormalities such as turbidity or precipitation were observed in this liquid crystal alignment agent, and it was confirmed to be a uniform solution. (Example 2) 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, NMP (0.833 g), GBL (3.00 g), and BCS (2.00 g) were added, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (V-2). No abnormalities such as turbidity or precipitation were observed in this liquid crystal alignment agent, and it was confirmed to be a uniform solution. (Example 3) 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, NMP (0.833 g), GBL (3.00 g), and BCS (2.00 g) were added, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (V-3). No abnormalities such as turbidity or precipitation were observed in this liquid crystal alignment agent, and it was confirmed to be a uniform solution.

[0151] (Comparative Example 1) To the polymer solution [2] (4.17 g) obtained in Polymer Synthesis Example 2, NMP (0.833 g), GBL (3.00 g), and BCS (2.00 g) were added, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (W-1). No abnormalities such as turbidity or precipitation were observed in this liquid crystal alignment agent, and it was confirmed to be a uniform solution.

[0152] <Fabrication of a Liquid Crystal Cell for Evaluating Liquid Crystal Alignment> The following shows a method for fabricating a liquid crystal cell for evaluating liquid crystal alignment. First, a substrate with electrodes was 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, an IZO electrode forming a counter electrode was formed over the entire surface as the first layer. On the first-layer counter electrode, as the second layer, a SiN (silicon nitride) film formed by CVD (chemical vapor deposition) was formed. The film thickness of the second-layer SiN film is 500 nm, which functions as an interlayer insulating film. On the second-layer SiN film, as the third layer, comb-shaped pixel electrodes formed by patterning an IZO film were arranged to form two pixels, namely a first pixel and a second pixel. The size of each pixel is 10 mm in length and approximately 5 mm in width. At this time, the first-layer counter electrode and the third-layer pixel electrode are electrically insulated by the action of the second-layer SiN film. The third-layer pixel electrode has a comb shape in which a plurality of electrode elements with a width of 3 μm and a central portion bent at an inner angle of 160° are arranged in parallel with a spacing of 6 μm. One pixel has a first region and a second region with a line connecting the bent portions of the plurality of electrode elements as a boundary. When comparing the first region and the second region of each pixel, the formation directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the direction of a line segment obtained by projecting the polarization plane of polarized ultraviolet light, which will be described later, onto the substrate is used as a reference, in the first region of the pixel, the electrode elements of the pixel electrode are formed at an angle of +80° (clockwise), and in the second region of the pixel, the electrode elements of the pixel electrode are formed at an angle of -80° (clockwise). That is, in the first region and the second region of each pixel, the directions of the in-plane switching operations of the liquid crystal induced by applying a voltage between the pixel electrode and the counter electrode are configured to be opposite to each other.

[0153] Next, the liquid crystal alignment agents obtained in Examples 1 to 3 and Comparative Example 1 were filtered through 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 for 120 seconds on a hot plate set at 80°C. Next, using an exposure apparatus (manufactured by USHIO INC., APL-L050121S1S-APW01), linearly polarized ultraviolet light was irradiated onto the substrate from the vertical direction through a wavelength selection filter and a polarizing plate. At this time, the polarization plane direction was set so that the direction of the line segment obtained by projecting the polarization plane of the polarized ultraviolet light onto the substrate was inclined by 80° with respect to the third-layer IZO comb electrode. Next, baking was performed 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 subjected to an alignment treatment. Also, as a counter substrate, a glass substrate having columnar spacers with a height of 4 μm and an ITO electrode formed on the back surface was similarly obtained with a substrate with a polyimide liquid crystal alignment film subjected to an alignment treatment. These two substrates with liquid crystal alignment films were made into a set. A sealant (manufactured by Mitsui Chemicals, Inc., XN-1500T) was printed in a form leaving a liquid crystal injection port on one substrate, and the other substrate was bonded and pressure-bonded so that the liquid crystal alignment film surfaces faced each other and the directions of the line segments obtained by projecting the polarization plane of the polarized ultraviolet light onto the substrates were parallel. Then, the sealant was cured to produce an empty cell with a cell gap of 4 μm. Liquid crystal MLC-7026 (manufactured by Merck KGaA, negative-type liquid crystal) was injected into this empty cell by a vacuum injection method, and the injection port was sealed to obtain a liquid crystal cell of the FFS mode. Then, the obtained liquid crystal cell was heated at 120°C for 60 minutes, left standing overnight at 23°C, and then used for the evaluation of liquid crystal alignment properties.

[0154] <Evaluation of Liquid Crystal Alignment Properties> The liquid crystal alignment state in the liquid crystal cell prepared by the above procedure was observed using a polarizing microscope (manufactured by Nikon Corporation, ECLIPSE E600 POL). Those in which the liquid crystal alignment could be confirmed and there was no flow alignment were rated as "good", and those in which the alignment could not be confirmed and those with flow alignment were judged as "bad". The results are shown in Table 1.

[0155] After aging the liquid crystal cell fabricated by the above procedure on a backlight for 5 days, a voltage of 1 V was applied for 60 μs at a temperature of 60°C, and the voltage after 500 ms was measured. The voltage holding ratio, which indicates how well the voltage can be maintained, was calculated. For the measurement of the voltage holding ratio, VHR-1 manufactured by Toyo Technica Co., Ltd. was used. The results are shown in Table 1. Note that a higher value of the voltage holding ratio indicates better performance.

[0156]

Table 1

[0157] As can be seen from the above results, it was found that the liquid crystal alignment films obtained from the liquid crystal alignment agents (V-1) to (V-3) using diamine (WA-1) exhibit the same liquid crystal alignment properties as the liquid crystal alignment film obtained from the liquid crystal alignment agent (W-1) using diamine (C1). On the other hand, it was found that the liquid crystal alignment films obtained from the liquid crystal alignment agents (V-1) to (V-3) using diamine (WA-1) have good voltage holding ratios even after being placed on the backlight for 5 days, as compared with the liquid crystal alignment film obtained from the liquid crystal alignment agent (W-1) using diamine (C1). Specifically, this is shown in the comparison between Examples 1 to 3 and Comparative Example 1 shown in Table 1. From the above, by using a diamine having an imide ring skeleton and a nitrogen atom-containing heterocyclic ring, a liquid crystal alignment film having high liquid crystal alignment properties and a high voltage holding ratio after long-term irradiation with backlight light can be obtained.

Industrial Applicability

[0158] The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can be suitably used for various liquid crystal display elements typified by liquid crystal display elements using the IPS driving method or the FFS driving method. And these display elements are not limited to liquid crystal displays for display purposes, and are further useful in light control windows and optical shutters that control the transmission and blocking of light.

[0159] The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2020-074709, filed on April 20, 2020, are hereby incorporated by reference herein and made a part of the disclosure of the specification of the present invention.

Claims

1. At least one polymer (A) selected from the group consisting of a polymer obtained by 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 a liquid crystal aligning agent containing an organic solvent. 【Chemical Formula 1】 (In the formula, X １ represents a tetravalent organic group represented by the following formula (g), and Ar represents a divalent nitrogen atom-containing heterocyclic ring. The two Ars may be the same or different.) 【Chemical Formula 2】 (R １ to R ４ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, provided that R １ to R ４ all represent hydrogen atoms, or at least two of R １ to R ４ represent groups other than the hydrogen atom in the above definition.)

2. The liquid crystal aligning agent according to claim 1, wherein the tetravalent organic group represented by (g) is any one of the following formulas (X1-1) to (X1-6). 【Chemical Formula 3】

3. The liquid crystal aligning agent according to claim 1 or 2, wherein the nitrogen atom-containing heterocyclic ring is a 5-membered aromatic heterocyclic ring 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 6-membered aromatic heterocyclic ring selected from a pyridine ring, a pyrimidine ring, a pyridazine ring, and a pyrazine ring, provided that any hydrogen atom of the nitrogen atom-containing heterocyclic ring may be substituted with a monovalent substituent.

4. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein the diamine represented by formula (1) is any one of the diamines represented by the following formulas (1-1) to (1-2). 【Chemical Formula 4】

5. The liquid crystal aligning agent according to any one of claims 1 to 4, wherein 10 to 100 mol% of the diamine component is a diamine represented by the formula (1).

6. The liquid crystal aligning agent according to any one of claims 1 to 5, wherein the diamine component further contains a diamine represented by the following formula (2) or (2i). 【Chemical Formula 5】 (Y ２ 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'). Two Rs and Y ２ｉ each independently have the above definitions.) 【Chemical Formula 6】 (Ar represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring. Two Ars may be the same or different, and any hydrogen atom on the benzene ring, biphenyl structure, or naphthalene ring may be substituted with a monovalent substituent. p is an integer of 0 or 1. Q ２ is -(CH ２ ) ｎ -(n is an integer of 2 to 18), or a group in which at least a part of the -CH ２ - of the -(CH ｎ ) ２ - is replaced with any one of -O-, -C(=O)-, or -O-C(=O)-. * represents a bond.) 【Chemical Formula 7】 (Ar' represents a divalent benzene ring or a biphenyl structure. Two Ar's may be the same or different, and any hydrogen atom on the benzene ring or biphenyl structure may be substituted with a monovalent substituent. p' is an integer of 0 or 1. Q ２’ is -(CH ２ ) ｎ -(n is an integer of 2 to 18), or a group in which at least a part of the -CH ２ ) ｎ - of the -(CH ２- represents a group in which at least a part of - is replaced by any one of -O-, -C(=O)-, or -O-C(=O)-. * represents a bond. ) **Claim 7**: The liquid crystal aligning agent according to claim 6, wherein the diamine component contains a diamine represented by the formula (2), and the divalent organic group represented by the formula (O) is any one of the following formulas (o-1) to (o-16). 【Chemical Formula 8】 【Chemical Formula 9】 (In the formula (o-14), the two m's may be the same or different.) 【Chemical Formula 10】 **Claim 8** The liquid crystal aligning agent according to any one of claims 1 to 7, wherein the tetracarboxylic acid derivative component contains a compound represented by the following formula (3) or a derivative thereof. 【Chemical Formula 11】 (X represents a structure selected from the group consisting of the following (x-1) to (x-13).) 【Chemical Formula 12】 (R １ ~R ４ each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a monovalent organic group having 1 to 6 carbon atoms containing a chlorine atom or 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 A １ and A ２ each independently represents a single bond, -O-, -CO-, -COO-, a phenylene group, a sulfonyl group, or an amide group. *1 is a bond connecting to one acid anhydride group, and *2 is a bond connecting to the other acid anhydride group. The two A ２ may be the same or different. ) **Claim 9** The liquid crystal aligning agent according to any one of claims 1 to 8, wherein the diamine component contains a diamine having at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocyclic ring, a secondary amino group, and a tertiary amino group (however, the diamine represented by the above formula (1) is excluded).

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

11. The liquid crystal aligning agent according to any one of claims 1 to 10, further containing at least one polymer (B) selected from the group consisting of a polymer obtained by using a tetracarboxylic acid derivative component and a diamine component not containing the diamine represented by the above formula (1) and an imidized polymer thereof.

12. A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 11.

13. A liquid crystal display element including the liquid crystal alignment film according to claim 12.

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

15. The method for manufacturing a liquid crystal alignment film according to claim 14, further including the following step (4). Step (4): A step of baking 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 manufacturing a liquid crystal alignment film according to claim 14 or 15, wherein step (2) is a step of heating in a temperature range of 40 to 180°C to obtain a film.

17. A diamine represented by the following formula (1-1) or (1-2). [Chemical Formula 13]

18. A polymer obtained from a diamine component containing the diamine represented by the formula (1-1) or (1-2) according to claim 17.

19. A polymer obtained by polycondensation reaction of a diamine component containing the diamine represented by the formula (1-1) or (1-2) according to claim 17 and a tetracarboxylic acid derivative component, or an imidized polymer thereof.

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