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

Abstract

The present invention addresses the problem of providing: a liquid crystal alignment agent which makes it possible to produce a liquid crystal alignment film having excellent film hardness at low cost; and a liquid crystal display element equipped with the liquid crystal alignment film. Further provided is a liquid crystal alignment agent which makes it possible to produce a liquid crystal alignment film and a liquid crystal display element which are superior in various properties other than film hardness.　The liquid crystal alignment agent is characterized by comprising a component (A).　Component (A): at least one polymer (A) selected from the group consisting of a (polyimide precursor)-polyurea copolymer having a repeating unit represented by formula (m1) and a repeating unit represented by formula (1) and an imidized polymer of the copolymer, in which at least one of the repeating unit represented by formula (m1) and the repeating unit represented by formula (1) is derived from an aromatic diamine (a) having any one of the structures respectively represented by formulae (S1) to (S2), and the polymer (A) can be produced without using an aliphatic diamine. (The meaning of each of the substituents is as defined in the description.)

Description

[Technical field]

[0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display device having the liquid crystal alignment film. [Background technology]

[0002] Conventionally, various driving methods have been developed for liquid crystal display elements, which differ in electrode structure and physical properties of liquid crystal molecules used, and various display elements such as TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, VA (Vertical Alignment) type, IPS (In-Plane Switching) type, and FFS (Fringe Field Switching) type are known. These liquid crystal display elements have a liquid crystal alignment film for aligning the liquid crystal molecules. Known materials for the liquid crystal alignment film include, for example, polyamic acid, polyamic acid ester, polyimide, and polyamide. In a VA-type liquid crystal display element, which is one of the driving methods for liquid crystal display elements, a PSA (Polymer Sustained Alignment) type liquid crystal display element has been proposed as a technology for increasing the response speed of liquid crystal, in which a photopolymerizable compound is added to the liquid crystal composition in advance, and ultraviolet light is irradiated while a voltage is applied to a liquid crystal cell equipped with a polyimide liquid crystal alignment film (see, for example, Patent Document 1 and Non-Patent Document 1).

[0003] In recent years, large-screen, high-definition LCD televisions have become mainstream, and small display terminals such as smartphones and tablet PCs have become more widespread, so that the demand for high quality LCD elements is increasing more than ever before. Against this background, various liquid crystal alignment agents have been proposed to improve the performance of liquid crystal alignment films and to improve various characteristics of liquid crystal display elements (e.g., liquid crystal alignment, voltage holding ratio, etc.) (see, for example, Patent Document 2). In addition to the above characteristics, high film hardness is also required. If a liquid crystal alignment film with low film hardness is used in a liquid crystal display element, the film is scraped during the manufacturing process of the liquid crystal display element, causing poor alignment of the liquid crystal at the scraped portion, resulting in the generation of bright spots and a decrease in display quality. In addition to the manufacturing process, touch panel displays have become widespread in recent years, and high film hardness is required to prevent the film from being scraped by touch panel operation. As a means for solving the above problem, Patent Document 3 proposes a polyimide-based liquid crystal alignment agent obtained by using a specific tetracarboxylic dianhydride having a carbon-carbon triple bond. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-307720 A [Patent Document 2] WO2014 / 126102 publication [Patent Document 3] JP 2019-014837 A [Non-patent literature]

[0005] [Non-Patent Document 1] K.Hanaoka,SID 04 DIGEST, P1200-1202 Summary of the Invention [Problem to be solved by the invention]

[0006] When the present inventors produced a liquid crystal alignment film using the method described in Patent Document 2, it became clear that the film hardness of the obtained alignment film was low. In addition, although it is possible to produce a liquid crystal alignment film using the method described in Patent Document 3, there is a disadvantage in that the cost of the liquid crystal alignment agent using this is high because it is necessary to newly synthesize tetracarboxylic dianhydride.

[0007] The present invention aims to provide a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film having excellent film hardness at low cost, and a liquid crystal display element having the liquid crystal alignment film. Another aim of the present invention is to provide a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film and a liquid crystal display element having excellent properties other than film hardness. [Means for solving the problem]

[0008] Means for Solving the Problems The present inventors have conducted intensive research to achieve the above object, and as a result have found that a liquid crystal aligning agent containing a specific component is effective in achieving the above object, thereby completing the present invention.

[0009] The present invention is based on these findings and has the following gist. A liquid crystal aligning agent comprising the following component (A): Component (A): at least one polymer (A) selected from the group consisting of a polyimide precursor-polyurea copolymer having a repeating unit represented by the following formula (m1) and a repeating unit represented by the following formula (1), and an imidized polymer thereof, wherein at least one of the repeating unit represented by the above formula (m1) and the repeating unit represented by the above formula (1) is derived from an aromatic diamine (a) having any of the structures represented by the following formulas (S1) to (S2), and the above polymer (A) is obtained without using an aliphatic diamine. [ka] (X1 represents a tetravalent organic group. Y1 represents a divalent organic group derived from an aromatic diamine. Two R1s each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Two Z1s each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkenyl group having 2 to 10 carbon atoms which may have a substituent, an alkynyl group having 2 to 10 carbon atoms which may have a substituent, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group.) [ka] (A1 is a divalent organic group, A2 is a divalent organic group derived from an aromatic diamine, and C1 and C2 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) [ka] (X 1 and X 2 are each independently a single bond, -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -COO-, -OCO- or -((CH2) a1 -A1) m1 In this, a1 is an integer of 1 to 15, A1 is an oxygen atom or -COO-, and m1 is an integer of 1 to 2. 1 and G 2 Each independently represents a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms and a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted. Each of m and n independently represents an integer of 0 to 3, and m+n is 1 to 6, preferably 1 to 4. R 1 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; R 1 Any hydrogen atom forming X may be substituted with a fluorine atom. 1 , X 2 , G 1 , G 2 , if a1 and A1 exist multiple times, then multiple X 1 , X 2 , G 1 , G 2 , a1 and A1 each independently have the above definition. [ka] (X 2a represents -CONH-, -NHCO-, -O-, -CHO-, -COO- or -OCO-. 2 represents a structure having a steroid skeleton.) Effect of the Invention

[0010] According to the liquid crystal aligning agent of the present invention, a liquid crystal alignment film and a liquid crystal display element having excellent film hardness can be obtained at low cost. Furthermore, according to the liquid crystal aligning agent of the present invention, a liquid crystal alignment film and a liquid crystal display element having excellent properties other than film hardness can be obtained. The mechanism by which the above-mentioned effects of the present invention are obtained is not entirely clear, but one of the reasons is thought to be that by using an aromatic diamine as a constituent component of the above-mentioned polymer, the resulting polymer can form stacking between aromatic rings, and also has urea bonds within the molecule, which allows many hydrogen bonds to be formed in the film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In this specification, the term "aromatic diamine" refers to a diamine in which at least one amino group is directly bonded to an aromatic ring, and which may contain an aliphatic group as part of its structure. The term "aliphatic diamine" refers to a diamine in which two amino groups are directly bonded to an aliphatic group, and which may contain an aromatic group as part of its structure. Aliphatic groups include both acyclic aliphatic groups and cyclic aliphatic groups (alicyclic groups). In this specification, examples of a halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0012] Hereinafter, each component contained in the liquid crystal aligning agent of the present disclosure and other components that are optionally blended as necessary will be described. <Polymer (A)> The liquid crystal aligning agent of the present invention is at least one polymer (A) selected from the group consisting of a polyimide precursor-polyurea copolymer having a repeating unit represented by the above formula (m1) and a repeating unit represented by the above formula (1) and an imidized polymer thereof, wherein at least one of the repeating units possessed by the polymer (A) is derived from an aromatic diamine (a) having a structure represented by the above formulas (S1) to (S2), and the polymer (A) is obtained without using an aliphatic diamine.

[0013] (Aromatic diamine (a)) At least one of the repeating unit represented by formula (m1) and the repeating unit represented by formula (1) is derived from an aromatic diamine (a) having any of the structures represented by formulas (S1) to (S2). The aromatic diamine (a) is preferably an aromatic diamine having the structure represented by formula (S1) to (S2) in its side chain.

[0014] Specific examples of the structures represented by the above formulae (S1) to (S2) include structures represented by the following formulae (S1-1) to (S1-7) and (S2-a). In formula (S2-a), X represents formula (X1), formula (X2) or -CH2O-, Col represents formula (Col-1), formula (Col-2) or formula (Col-3), G represents formula (G1), formula (G2), formula (G3) or formula (G4), and * represents a bond. [ka]

[0015] In the above formula, R 1 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. p is -(CH2) a A1 represents an oxygen atom or -COO-* (wherein the bond marked with "*" is (CH2)), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CHO-, -CHOCO-, -COO-, or -OCO-. a2 A2 is an oxygen atom or *-COO- (where the bond marked with "*" is (CH2) a2 each of a1 and a3 independently represents an integer of 0 or 1, a2 represents an integer of 1 to 10, and Cy represents a 1,4-cyclohexylene group or a 1,4-phenylene group. [ka]

[0016] The aromatic diamine (a) preferably has at least one benzene ring, and more preferably has a carbon number of 6 to 50. Specific examples of the aromatic diamine (a) include diamines represented by the following formula (d1) or formula (d2). [ka] (X is a single bond, -O-, -C(CH3)2-, -NH-, -CO-, -(CH2) m -, -SO2-, -O-(CH2) m -O-, -OC(CH3)2-, -CO-(CH2) m -, -NH-(CH2) m -, -SO2-(CH2) m -, -CONH-(CH2) m -, -CONH-(CH2) m -NHCO- or -COO-(CH2) m represents a divalent organic group of -OCO-. m is an integer of 1 to 8. Y represents any of the structures of the above formulae (S1) to (S2). In the above formula (d2), the two Y's may be the same or different.

[0017] Preferred examples of the diamine represented by the above formula (d1) include the following formulas (d1-1) to (d1-6): Preferred examples of the diamine represented by the above formula (d2) include the following formulas (d2-1) to (d2-6): [ka] [ka] (X v1 ~X v4 , X p1 ~X p8 are each independently -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CHO-, -CH2-OCO-, -COO-, or -OCO-; X V5 ~X V6 , Xs1 ~X s4 Each independently represents -O-, -CH2O-, -COO- or -OCO-. X a ~X f are each independently a single bond, -O-, -NH-, or -O-(CH2) m -O- (m is an integer of 1 to 8), R v1 ~R v4 , R 1a ~R 1h are each independently: -C n H 2n+1 (n is an integer from 1 to 20), -OC n H 2n+1 (n is an integer from 2 to 20).

[0018] The repeating unit of the polymer (A) may be derived from an aromatic diamine other than the aromatic diamine (a) (hereinafter, also referred to as "other aromatic diamine"). Specific examples of other aromatic diamines include p-phenylenediamine, m-phenylenediamine, 4-(2-(methylamino)ethyl)aniline, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, or diamine compounds having a carboxy group such as the diamine compounds represented by the following formulae (3b-1) to (3b-4), 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylether ...methane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane phenyl ether, 1,2-bis(4-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,2-bis(4-aminophenoxy)ethane, 1,2-bis(4-amino-2-methylphenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4 -aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 4-(2-(4-aminophenoxy)ethoxy)-3-fluoroaniline, di(2-(4-aminophenoxy)ethyl)ether, 4-amino-4'-(2-(4-aminophenoxy)ethoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 1,4-di Diamines having a urea bond such as aminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2'-bis(4-aminophenyl)propane, 1,3-bis(4-aminophenethyl)urea, 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,diamines having a photopolymerizable group at the end, such as N-diallylaniline; diamines having a radical initiating function, such as those represented by the following formulas (R1) to (R5); diamines having a photosensitizing function that exhibits a sensitizing effect upon irradiation with light, such as 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, and 9,9-bis(4-aminophenyl)fluorene; 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole; Examples of aromatic diamines having 6 to 30 carbon atoms include, but are not limited to, diamines having a heterocycle such as those represented by formulae (z-1) to (z-18), diamines having a diphenylamine skeleton such as those represented by formulae (Dp-1) to (Dp-9) below, diamines having a group "-N(D)-" (D represents a protecting group which is eliminated by heating and is replaced with a hydrogen atom, preferably a tert-butoxycarbonyl group) such as those represented by formulae (5-1) to (5-10) below, and diamines having an oxazoline structure such as those represented by formulae (Ox-1) to (Ox-2) below. [ka] (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-, -CHO-, -OCH2-, -COO-, -OCO-, -CO-N(CH3)- or -N(CH3)-CO-; m1 and m2 each independently represent an integer of 0 to 4, and m1+m2 represents an integer of 1 to 4. 3 and m 4 Each independently represents an integer of 1 to 5. In formula (3b-3), A 2 represents a linear or branched alkyl group having 1 to 5 carbon atoms, and m5 represents an integer of 1 to 5. 3 and A 4each independently represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CHO-, -OCH2-, -COO-, -OCO-, -CO-N(CH3)- or -N(CH3)-CO-, and m6 represents an integer of 1 to 4. [ka] [ka] [ka] (n is an integer from 1 to 6.) [ka] [ka] (Boc represents a tert-butoxycarbonyl group.) [ka]

[0019] The above 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, diamines having a photopolymerizable group at the terminal, diamines represented by the above formulae (R1) to (R5), and diamines represented by the above formulae (z-1) to (z-18) may be used alone or in combination when producing polymer (A), in order to increase the response speed of a liquid crystal display element using a PSA mode or an SC-PVA mode.

[0020] As the other aromatic diamines, among the above, from the viewpoint of suitably obtaining the effects of the present invention, p-phenylenediamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,N-diallylaniline, diamines represented by the above formulas (R1) to (R5), diamines represented by the above formulas (z-1) to (z-18), diamines represented by the above formulas (Dp-1) to (Dp-9), and diamines represented by the above formulas (Ox-1) to (Ox-2) are preferred.

[0021] (Repeating unit represented by formula (m1)) In the above formula (m1), Y1 represents a divalent organic group derived from an aromatic diamine. Examples of the aromatic diamine include the above aromatic diamine (a) and the other aromatic diamines. At least one of Y1 in the above formula (m1) and A2 in the above formula (1) represents a divalent organic group derived from an aromatic diamine (a).

[0022] In the above formula (m1), X1 represents a tetravalent organic group. X1 is preferably a tetravalent organic group derived from tetracarboxylic dianhydride or a derivative thereof. Examples of the tetravalent organic group include a tetravalent organic group derived from an aliphatic tetracarboxylic dianhydride or a derivative thereof, a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride or a derivative thereof, or a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride or a derivative thereof. X1 is preferably a tetravalent organic group derived from a tetracarboxylic dianhydride or a derivative thereof represented by the following formula (3). [ka] (X represents a structure selected from any one of the following formulas (x-1) to (x-13).) [ka] (R 1 ~R 4R each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. 5 and R 6 Each of A1 and A2 independently represents a hydrogen atom or a methyl group. Each of j and k represents an integer of 0 or 1, and A1 and two A2 independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or an amide group. *1 represents a bond bonded to one acid anhydride group, and *2 represents a bond bonded to the other acid anhydride group. In the above formula (x-13), two A2 may be the same or different from each other.)

[0023] More preferred specific examples of the above formula (x-1) include the following formulae (X1-1) to (X1-6), in which * represents a bond.

[0024] [ka]

[0025] Preferred specific examples of the above formulae (x-12) and (x-13) include the following formulae (x-14) to (x-29), in which * represents a bond. [ka] [ka]

[0026] Preferred examples of the tetracarboxylic dianhydride represented by the above formula (3) or a derivative thereof include tetracarboxylic dianhydrides represented by the formula (3) in which X is any of the above formulae (x-1) to (x-7) and (x-11) to (x-13) or a derivative thereof.

[0027] In the above formula (m1), two R1 each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and preferably represent a hydrogen atom or a methyl group. In the above formula (m1), two Z1 each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkenyl group having 2 to 10 carbon atoms which may have a substituent, an alkynyl group having 2 to 10 carbon atoms which may have a substituent, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group, and preferably represents a hydrogen atom or a methyl group. In the above formula (m1), each of X1, Y1, R1, and Z1 may be one type or two or more types.

[0028] (Repeating unit represented by formula (1)) In the above formula (1), A1 is a divalent organic group. A1 is preferably a divalent organic group derived from a diisocyanate. Examples of A1 include a divalent aromatic group having 6 to 30 carbon atoms and at least one benzene ring, and a divalent aliphatic or alicyclic group having 4 to 30 carbon atoms. Specific examples of A1 include divalent organic groups derived from aromatic diisocyanates such as o-phenylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, toluene diisocyanates (e.g., 2,4-triylene diisocyanate), 1,4-diisocyanate-2-methoxybenzene, 2,5-diisocyanate xylenes, 2,2'-bis(4-phenyl diisocyanate)propane, 4,4'-diisocyanate diphenylmethane, 4,4'-diisocyanate diphenyl ether, 4,4'-diisocyanate diphenyl sulfone, 3,3'-diisocyanate diphenyl sulfone, and 2,2'-diisocyanate benzophenone; and divalent organic groups derived from acyclic aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, and tetramethylene diisocyanate. Among these, A1 is preferably a divalent organic group derived from 2,4-trilen diisocyanate from the viewpoints of availability, polymerization reactivity, and voltage holding ratio.

[0029] In the above formula (1), A2 is a divalent organic group derived from an aromatic diamine. Examples of the aromatic diamine include the above aromatic diamine (a) and the other aromatic diamines.

[0030] At least one of Y1 in the above formula (m1) and A2 in the above formula (1) represents a divalent organic group derived from the above aromatic diamine (a). In the above formula (1), C1 and C2 each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and preferably a hydrogen atom or a methyl group. In the above formula (1), each of A1, A2, C1, and C2 may be one type or two or more types.

[0031] (Repeating units constituting polymer (A)) The polymer (A) in the present invention has a repeating unit represented by the above formula (m1) and a repeating unit represented by the above formula (1). The polymer (A) may have a repeating unit represented by the above formula (m1), a repeating unit represented by the above formula (1), and a terminal group. The polymer (A) may have any repeating unit other than the repeating unit represented by the above formula (m1) and the repeating unit represented by the above formula (1) (hereinafter, also referred to as other repeating units), but is preferably composed of a repeating unit represented by the above formula (m1), a repeating unit represented by the above formula (1), and a terminal group.

[0032] Here, the term "terminal group" refers to a group bonded to the end of the repeating unit constituting the polymer (A). Examples of the terminal group include an amino group, a carboxy group, an acid anhydride group, an isocyanate group, or a derivative thereof. The amino group, the carboxy group, the acid anhydride group, and the isocyanate group can be obtained by a normal condensation reaction, and the derivative can be obtained by modifying the terminal group, for example, using a terminal modifier, as described later.

[0033] The polymer (A) is obtained without using an aliphatic diamine. Therefore, the polymer (A) does not contain a group derived from an aliphatic diamine. That is, the repeating unit represented by the formula (m1) and the repeating unit represented by the formula (1) do not contain a group derived from an aliphatic diamine. Similarly, the other repeating units do not contain a group derived from an aliphatic diamine.

[0034] The content of the repeating unit represented by formula (m1) is preferably from 10 to 90 mol %, and more preferably from 25 to 75 mol %, of all the repeating units constituting the polymer (A). The content of the repeating unit represented by formula (1) is preferably from 10 to 90 mol %, and more preferably from 25 to 75 mol %, of all the repeating units constituting the polymer (A). The sum of the repeating units represented by (m1) in which Y1 is a divalent organic group derived from the aromatic diamine (a) and the repeating units represented by (1) in which A2 is a divalent organic group derived from the aromatic diamine (a) is preferably 10 to 90 mol %, more preferably 10 to 85 mol %, of all the repeating units constituting the polymer (A).

[0035] <Polymer (B)> From the viewpoint of improving electrical properties, the liquid crystal aligning agent of the present invention may further contain at least one polymer (B) selected from the group consisting of polyimide precursors and imidized polymers thereof, which is different from the polymer (A). In particular, by further containing the polymer (B), the liquid crystal alignment property can be improved. The polymer (B) is preferably at least one polymer selected from the group consisting of a polyimide precursor having a repeating unit represented by the following formula (m2) and an imidized polymer thereof.

[0036] [ka] (X2 represents a tetravalent organic group. Y2 represents a divalent organic group. R2 and Z2 have the same meanings as R1 and Z1 in formula (m1), respectively, and two R2s and two Z2s may be the same or different.)

[0037] The polymer (B) preferably does not have a repeating unit represented by the above formula (1). The tetravalent organic group in X2 may be a tetravalent organic group derived from an aliphatic tetracarboxylic dianhydride, a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride, or a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride, and specific examples thereof include the tetravalent organic groups exemplified for X1 in the above formula (m1). From the viewpoint of efficiently obtaining the effects of the present invention, the tetravalent organic groups represented by the above formulas (x-1) to (x-13) (collectively referred to as specific tetravalent organic groups) are preferred.

[0038] From the viewpoint of efficiently obtaining the effects of the present invention, the polymer (B) preferably contains repeating units in which X2 is the specific tetravalent organic group in an amount of 5 mol % or more, and more preferably 10 mol % or more, of all repeating units contained in the polymer (B). It is preferable that the polymer (B) has repeating units in which X2 is any of the above formulae (x-1) to (x-11) and repeating units in which X2 is any of the above formulae (x-12) to (x-13).

[0039] Specific examples of Y2 include divalent organic groups derived from aromatic diamines exemplified in the polymer (A) and divalent organic groups derived from organosiloxane-containing diamines such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane. From the viewpoint of improving electrical properties, the polymer (B) is preferably a polymer containing a repeating unit in which Y2 is a divalent organic group (collectively referred to as a specific divalent organic group) obtained by removing two amino groups from a diamine selected from a diamine having a nitrogen atom-containing structure and a diamine having a carboxy group such as 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).

[0040] From the viewpoint of improving electrical properties, polymer (B) may contain repeating units in which Y2 is the specific divalent organic group in an amount of 1 mol % or more, or 5 mol % or more, of all repeating units contained in polymer (B).

[0041] From the viewpoint of improving electrical properties, the content ratio of the (A) component and the (B) component may be 10 / 90 to 90 / 10, 20 / 80 to 90 / 10, or 20 / 80 to 80 / 20, in terms of the mass ratio of [(A) component] / [(B) component].

[0042] <Production of Polymer (A) and Polymer (B)> The polyimide precursor-polyurea copolymer, which is the above-mentioned polymer (A), can be produced, for example, by reacting a component (a) containing a compound having two isocyanate groups in the molecule, a component (b) containing a compound having two primary or secondary amino groups in the molecule, and a component (c) containing a tetracarboxylic dianhydride or a derivative thereof. Each of the components (a), (b) and (c) may be one type or two or more types.

[0043] An example of the component (a) is a compound represented by O=C=N-A1-N=C=O (A1 is the same as A1 in formula (1)).

[0044] An example of the component (b) is a compound represented by the following formula [b]. [ka] (In formula [b], C1, C2, and A2 are the same as C1, C2, and A2 in formula (1).) Specific examples of the compound represented by the above formula [b] include the above aromatic diamine (a) and the other aromatic diamines.

[0045] The component (b) may contain, for example, an aromatic diamine having at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocycle (excluding imide rings contained in polyimides), a secondary amino group, and a tertiary amino group, but does not contain an aliphatic diamine.

[0046] Examples of the nitrogen atom-containing heterocycle 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 these, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, or acridine is preferred.

[0047] The secondary amino group and tertiary amino group that the diamine having a nitrogen atom-containing structure may have are represented, for example, by the following formula (n). [ka] In the above formula (n), R represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. "*" represents a bond bonded to the hydrocarbon group.

[0048] Examples of the monovalent hydrocarbon group R in the above formula (n) include alkyl groups such as methyl, ethyl, and propyl groups; cycloalkyl groups such as cyclohexyl groups; and aryl groups such as phenyl and methylphenyl groups. R is preferably a hydrogen atom or a methyl group.

[0049] Specific examples of diamines having a nitrogen atom-containing structure include 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, diamines represented by the above formulas (z-1) to (z-18), and diamines represented by the above formulas (Dp-1) to (Dp-9).

[0050] Examples of the tetracarboxylic dianhydride or derivative thereof contained in the component (c) include the tetracarboxylic dianhydride or derivative thereof represented by the above formula (3).

[0051] The tetracarboxylic dianhydride represented by formula (3) or a derivative thereof preferably accounts for 1 mol % or more of the entire component (c), more preferably 5 mol % or more, and particularly preferably 10 mol % or more.

[0052] The reaction of components (a), (b) and (c) is usually carried out in an organic solvent. The organic solvent used in this reaction is not particularly limited as long as it dissolves the resulting polyimide precursor-polyurea copolymer. Specific examples include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene Glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, 1,Examples of the solvent include 4-dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, and 4-hydroxy-4-methyl-2-pentanone. These may be used alone or in combination. Furthermore, even if the solvent does not dissolve the polyimide precursor, it may be mixed with the above solvent and used as long as the generated polyimide precursor does not precipitate. In addition, since moisture in the organic solvent inhibits the polymerization reaction and may cause hydrolysis of the resulting polyimide precursor, it is preferable to use an organic solvent that has been dehydrated and dried.

[0053] The order of reacting the (a), (b) and (c) components may be, for example, to react the (a) and (b) components first, and then add and react the (c) component. This reaction is preferable because the polyimide precursor having the repeating unit represented by formula (m1) obtained by the reaction is a random copolymer in which the repeating unit represented by formula (1) and the repeating unit represented by formula (m1) are randomly bonded.

[0054] On the other hand, in a method including a step of reacting component (a) with component (b) to obtain a urea-based polymer having a repeating unit represented by formula (1), and a step of reacting component (b) with component (c) to obtain a polyimide precursor having a repeating unit represented by formula (m1), and then reacting the obtained urea-based polymer having the repeating unit represented by formula (1) with the polyimide precursor having the repeating unit represented by formula (m1), the obtained polymer having the repeating unit represented by formula (1) has a structure like a block copolymer of polyurea and polyimide precursor, that is, a polymer structure consisting of a urea-based polymer and a polyimide precursor each having a higher degree of polymerization compared to the above-mentioned random copolymer.

[0055] The temperature at which the components (a), (b) and (c) are reacted can be selected from the range of -20 to 150°C, but is preferably in the range of -5 to 100°C. The reaction can be carried out at any concentration. The total concentration of the components (a), (b) and (c) in the reaction liquid is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration in the early stage of the reaction, and then an organic solvent can be added.

[0056] The ratio of the components (a), (b), and (c) to be reacted is, for example, preferably such that the total amount of the components (a) and (c): the component (b) is 0.8:1 to 1.2:1 by mole. The ratio of the component (a) to the total amount of the components (a) and (c) is preferably 20 to 60 mol %.

[0057] Examples of the polyimide precursor that is the polymer (B) include polyamic acid and polyamic acid ester. The polyimide precursor that is the polymer (B) can be synthesized by a known method such as that described in International Publication WO2013 / 157586. The diamine component for producing the polyimide precursor that is the polymer (B) may contain a diamine having at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocycle (excluding the imide ring that the polyimide has), a secondary amino group, and a tertiary amino group. Examples of the nitrogen atom-containing structure are as described in the above description of the polymer (A).

[0058] [Terminal Modifier] In synthesizing the polymers (A) and (B) of the present invention, a terminal-modified polymer may be synthesized using a suitable terminal modifier together with the above-mentioned tetracarboxylic acid derivative component, diamine component, and optionally a diisocyanate component.

[0059] Examples of the terminal modifier include acid monoanhydrides such as acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, compounds represented by the following formulas (m-1) to (m-6), 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, and 4-ethynylphthalic anhydride; [ka] Examples of the dicarbonate diester compounds include di-tert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds include acryloyl chloride, methacryloyl chloride and nicotinic acid chloride; monoamine compounds include aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine and n-octylamine; and monoisocyanate compounds include ethyl isocyanate, phenyl isocyanate and naphthyl isocyanate.

[0060] The proportion of the terminal modifier used is preferably 20 parts by mol or less, and more preferably 10 parts by mol or less, based on 100 parts by mol of the total of the diamine components used.

[0061] Polyimide can be obtained by ring-closing (imidization) the polyimide precursor-polyurea copolymer of polymer (A) or the polyimide precursor of polymer (B) (hereinafter, collectively referred to simply as "polyimide precursor"). Note that the imidization ratio in this specification refers to the ratio of imide groups to the total amount of imide groups derived from tetracarboxylic dianhydride or its derivatives and carboxy groups (or their derivatives).

[0062] Methods for imidizing the polyimide precursor include thermal imidization, in which a solution of the polyimide precursor is heated as is, and catalytic imidization, in which a catalyst is added to a solution of the polyimide precursor.

[0063] The molecular weight of the polymers (A) and (B) used in the present invention is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000, in terms of weight average molecular weight measured by GPC (Gel Permeation Chromatography), taking into consideration the strength of the liquid crystal alignment film obtained therefrom, workability during film formation, and coating properties.

[0064] The blending ratio of the polymer components used in the manufacturing method of the liquid crystal alignment film of the present invention is not particularly limited, but for example, the total amount of the polymer components contained in the liquid crystal alignment agent is 0.1 to 30 mass%, preferably 3 to 10 mass%. The total content of the polymers (A) and (B) contained in the liquid crystal alignment agent is preferably 1 to 9 mass%, more preferably 1.5 to 9 mass%. The total also includes the case where one or more of the constituent unit elements are 0 mass%.

[0065] In addition, the liquid crystal alignment agent used for producing the liquid crystal alignment film may contain other polymers in addition to the polymer (A) and the polymer (B). In this case, the content of the other polymers is 0.5% by mass to 15% by mass, preferably 1% by mass to 10% by mass, of the total amount of the polymer components. Examples of the other polymers include acrylic polymers, methacrylic polymers, polystyrene, polyamide, and polysiloxane.

[0066] The solvent contained in the liquid crystal alignment agent is not particularly limited as long as it can dissolve the polymer (A). Examples of the solvent include lactone solvents such as γ-valerolactone and γ-butyrolactone; γ-butyrolactam, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, and N-(n Lactam solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, etc.;4-Hydroxy-4-methyl-2-pentanone, 2,6-dimethyl-4-heptanone (diisobutyl ketone), methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol Examples of the solvent include ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monobutyl ether, propylene glycol diacetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, isoamyl propionate, isoamyl isobutyrate, diisopropyl ether, and diisopentyl ether; carbonate solvents such as ethylene carbonate and propylene carbonate, 1-hexanol, cyclohexanol, 1,2-ethanediol, and 2,6-dimethyl-4-heptanol (diisobutyl carbinol). These can be used alone or in combination of two or more.

[0067] Preferred solvent combinations include N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, and N-methyl-2-pyrrolidone, γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone. and diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone and N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol diacetate, gamma-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone, gamma-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol diacetate, N-methyl-2-pyrrolidone, gamma-butyrolactone, propylene glycol monobutyl ether, and diisobutyl ketone, N-methyl-2 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, propylene glycol monobutyl ether, and dipropylene glycol dimethyl ether, etc. The type and content of such a solvent are appropriately selected depending on the coating device, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

[0068] <Liquid crystal alignment agent> The liquid crystal aligning agent of the present invention may contain other components other than those described above, such as a crosslinkable compound, a functional silane compound, a surfactant, a compound having a photopolymerizable group, etc., if necessary.

[0069] The crosslinkable compound can be used for the purpose of increasing the strength of the liquid crystal alignment film. Examples of such crosslinkable compounds include compounds having an isocyanate group or a cyclocarbonate group, or compounds having at least one group selected from the group consisting of lower alkoxyalkyl groups, as described in paragraphs

[0109] to

[0113] of International Publication WO2016 / 047771, as well as compounds having a blocked isocyanate group.

[0070] The blocked isocyanate compound is commercially available, and for example, Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (all manufactured by Tosoh Corporation), Takenate B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals, Inc.) and the like can be preferably used.

[0071] Specific examples of preferred crosslinkable compounds include compounds represented by the following formulas (CL-1) to (CL-11). [ka]

[0072] The above are examples of the crosslinkable compound, and the present invention is not limited to these. The crosslinkable compound used in the liquid crystal aligning agent of the present invention may be one type or a combination of two or more types.

[0073] The content of the other crosslinkable compound in the liquid crystal aligning agent of the present invention is 0.1 to 150 parts by mass, or 0.1 to 100 parts by mass, or 1 to 50 parts by mass, based on 100 parts by mass of the polymer component.

[0074] The functional silane compound can be used for the purpose of improving the adhesion between the liquid crystal alignment film and the base substrate. Specific examples include the silane compounds described in paragraph

[0019] of International Publication No. 2014 / 119682. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, based on 100 parts by mass of the polymer component.

[0075] The surfactant can be used for the purpose of improving the uniformity of the thickness and the surface smoothness of the liquid crystal alignment film. Examples of the compound include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. Specific examples of these include the surfactants described in paragraph

[0117] of International Publication WO2016 / 047771. The amount of the surfactant used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, based on 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

[0076] Examples of compounds having a photopolymerizable group include compounds having one or more polymerizable unsaturated groups, such as an acrylate group or a methacrylate group, in the molecule, such as compounds represented by the following formulas (M-1) to (M-7).

[0077] [ka]

[0078] Furthermore, the liquid crystal aligning agent of the present invention can be added with a nitrogen atom-containing heterocyclic amine compound represented by formula [M1] to formula [M156], more preferably 3-picolylamine and 4-picolylamine, as described in paragraphs

[0194] to

[0200] of International Publication WO2011 / 132751 (published on October 27, 2011), as a compound that promotes charge transfer in the liquid crystal alignment film and promotes charge escape from the element. This amine compound may be added directly to the liquid crystal aligning agent, but it is preferable to add it after making it into a solution with a concentration of 0.1 to 10% by mass, preferably 1 to 7% by mass. This solvent is not particularly limited as long as it dissolves the polymer component.

[0079] An imidization promoter or the like may be added to the liquid crystal aligning agent of the present invention for the purpose of efficiently promoting imidization by heating when baking the coating film.

[0080] The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent in the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., but is preferably in the range of 0.5 to 15 mass%, more preferably 1 to 10 mass%. The particularly preferred range of solid content varies depending on the method used to apply the liquid crystal alignment agent to the substrate. For example, in the case of the spin coating method, the solid content is particularly preferably in the range of 1.5 to 4.5 mass%. In the case of the printing method, the solid content is particularly preferably in the range of 3 to 9 mass%, thereby making the solution viscosity in the range of 12 to 50 mPa·s. In the case of the inkjet method, the solid content is particularly preferably in the range of 1 to 5 mass%, thereby making the solution viscosity in the range of 3 to 15 mPa·s.

[0081] <Liquid crystal alignment film / Liquid crystal display element> The liquid crystal alignment film of the present invention is obtained from the above liquid crystal aligning agent. The liquid crystal alignment film of the present invention can be used as a horizontal alignment type or vertical alignment type liquid crystal alignment film, and is particularly suitable for a vertical alignment type liquid crystal display element such as a VA mode or PSA mode. The liquid crystal display element of the present invention is provided with the above liquid crystal alignment film. The liquid crystal display element of the present invention can be produced, for example, by a method including the following steps (1) to (3) or steps (1) to (4). (1) A process of applying a liquid crystal alignment agent onto a substrate The liquid crystal alignment agent of the present invention is applied to one side of a substrate on which a patterned transparent conductive film is provided by an appropriate application method such as a roll coater method, a spin coat method, a printing method, an inkjet method, etc. The substrate is not particularly limited as long as it is a highly transparent substrate, and plastic substrates such as acrylic substrates and polycarbonate substrates can be used in addition to glass substrates and silicon nitride substrates. In addition, in a reflective liquid crystal display element, an opaque material such as a silicon wafer can be used for only one substrate, and in this case, a light-reflecting material such as aluminum can be used for the electrode. (2) The coating is baked After applying the liquid crystal alignment agent, it is preferable to first perform preheating (prebaking) for the purpose of preventing dripping of the applied alignment agent. The prebaking temperature is preferably 30 to 200° C., more preferably 40 to 150° C., and particularly preferably 40 to 100° C. The prebaking time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Then, it is preferable to further perform a heating (postbaking) step. The post-bake temperature is preferably 80 to 300° C., more preferably 120 to 250° C. The post-bake time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The film thus formed has a thickness of preferably 5 to 300 nm, more preferably 10 to 200 nm.

[0082] The coating film formed in the above step (1) can be used as a liquid crystal alignment film as it is, but the coating film may be subjected to an alignment ability imparting treatment, such as a rubbing treatment in which the coating film is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton, or a photoalignment treatment in which the coating film is irradiated with polarized or non-polarized radiation.

[0083] In the photo-alignment treatment, the radiation to be irradiated to the coating film may be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, the radiation may be applied from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When non-polarized radiation is applied, the radiation is applied in an oblique direction. (3) Forming the liquid crystal layer (3-1) VA type LCD element Two substrates on which a liquid crystal alignment film is formed are prepared as described above, and liquid crystal is placed between the two substrates arranged opposite each other. Specifically, the following two methods can be mentioned. The first method is a conventionally known method. First, the two substrates are arranged opposite each other with a gap (cell gap) between them so that the liquid crystal alignment films face each other. Next, the peripheries of the two substrates are bonded together using a sealant, and a liquid crystal composition is injected and filled into the substrate surfaces and the cell gap partitioned by the sealant to come into contact with the film surface, and then the injection hole is sealed.

[0084] The second method is a method called ODF (One Drop Fill) method. For example, a UV-curable sealant is applied to a predetermined location on one of the two substrates on which a liquid crystal alignment film is formed, and a liquid crystal composition is dropped at a predetermined number of locations on the liquid crystal alignment film surface. Thereafter, the other substrate is bonded so that the liquid crystal alignment film faces the other substrate, and the liquid crystal composition is spread over the entire surface of the substrate and contacted with the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. In either method, it is preferable to further remove the flow alignment during liquid crystal filling by heating to a temperature at which the liquid crystal composition used has an isotropic phase and then slowly cooling to room temperature.

[0085] (3-2) Manufacturing of PSA type liquid crystal display elements The procedure is the same as that of (3-1) above, except that a liquid crystal composition containing a polymerizable compound is injected or dropped. Examples of the polymerizable compound include the polymerizable compounds represented by the above formulas (M-1) to (M-7). (3-3) When a coating film is formed on a substrate using a liquid crystal alignment agent containing a compound having a polymerizable group A method of manufacturing a liquid crystal display element may be adopted in which, after the same procedure as in the above (3-1), a step of irradiating ultraviolet light described later is carried out. According to this method, a liquid crystal display element having excellent response speed can be obtained with a small amount of light irradiation, as in the case of manufacturing the above PSA type liquid crystal display element. The compound having a polymerizable group may be a compound having one or more polymerizable unsaturated groups in the molecule, such as acrylate groups or methacrylate groups, as represented by the above formulas (M-1) to (M-7), and the content thereof is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, relative to 100 parts by mass of the polymer component. The polymerizable group may be contained in a polymer used for a liquid crystal alignment agent, and an example of such a polymer is a polymer obtained by using a diamine component containing a diamine having the above photopolymerizable group at its terminal in a reaction.

[0086] (4) UV irradiation process The liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates obtained in (3-2) or (3-3) above. The voltage applied here can be, for example, 5 to 50 V DC or AC. The light to be irradiated can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm, but ultraviolet light containing light with a wavelength of 300 to 400 nm is preferred. The light source for the irradiation light can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like. The light irradiation dose is preferably 1,000 to 200,000 J / m 2 and more preferably 1,000 to 100,000 J / m 2 It is.

[0087] A liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell. Examples of the polarizing plate to be attached to the outer surface of the liquid crystal cell include a polarizing film called an "H film" made by absorbing iodine while stretching and aligning polyvinyl alcohol, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

[0088] The liquid crystal display element of the present invention can be effectively applied to various devices, and can be used in various display devices such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays. EXAMPLES

[0089] The present invention will be described below with reference to examples. However, the present invention is not limited to these examples. The abbreviations used below are as follows.

[0090] (Diisocyanate) A-1: 2,4-trilene diisocyanate

[0091] (Tetracarboxylic acid dianhydride) B-1: 1,2,3,4-cyclobutanetetracarboxylic dianhydride B-2: Pyromellitic anhydride

[0092] (Diamine compounds) C-1: 4,4'-diaminodiphenylmethane C-2: N-(3-picolyl)-3,5-diaminobenzamide C-3: 1,3-diamino-4-{4-(4-n-heptylcyclohexyl)phenoxy}benzene C-4: 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane C-5: 2,2-bis{4-(4-aminophenoxy)phenyl}propane C-1 to C-3 and C-5 are aromatic diamines, and C-4 is an aliphatic diamine.

[0093] (Organic solvent) NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve

[0094] The measurement methods used in this example are described below. (Polymer molecular weight measurement) The molecular weight of the polymer was measured by a GPC (room temperature gel permeation chromatography) device, and the number average molecular weight and weight average molecular weight were calculated as polyethylene glycol and polyethylene oxide equivalent values. GPC equipment: Showa Denko GPC-101, Column: Shodex column (KD-803, KD-805 in series) Column temperature: 50℃ Eluent: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr·H2O) 30mmol / L, phosphoric acid·anhydrous crystal (o-phosphoric acid) 30mmol / L, tetrahydrofuran (THF) 10ml / L) Flow rate: 1.0ml / min Standard samples for creating calibration curves: TSK standard polyethylene oxide (molecular weight: approx. 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol (molecular weight: approx. 12,000, 4,000, 1,000) manufactured by Polymer Laboratory Co., Ltd.

[0095] <Synthesis Example 1> C-1 (1.78 g, 9.00 mmol), C-2 (1.31 g, 5.36 mmol), C-3 (1.37 g, 3.59 mmol) and NMP (25 g) were added to a four-neck flask and stirred to completely dissolve the diamine. Next, A-1 (1.57 g, 9.00 mmol) and NMP (8.9 g) were added and reacted at 25 ° C for 1 hour. Then, B-1 (1.73 g, 8.82 mmol) and NMP (9.4 g) were added and reacted for another 16 hours to obtain a solution with a concentration of polyamic acid-polyurea copolymer (A) of 15 mass%. The number average molecular weight of this polyamic acid-polyurea copolymer (A) was 10,200 and the weight average molecular weight was 34,700.

[0096] <Comparative Synthesis Example 1> According to the method described in Synthesis Example 1 of paragraph

[0167] of WO2014 / 126102, a polyamic acid-polyurea solution containing a diamine other than an aromatic diamine was synthesized. C-4 (1.53 g, 8.98 mmol), C-2 (1.31 g, 5.36 mmol), C-3 (1.37 g, 3.59 mmol) and NMP (24 g) were added to a four-neck flask and stirred to completely dissolve the diamine. Next, A-1 (1.57 g, 9.00 mmol) and NMP (8.9 g) were added and reacted at 40° C. for 15 hours. After that, B-1 (1.66 g, 8.46 mmol) and NMP (9.4 g) were added and reacted for another 10 hours to obtain a solution with a concentration of polyamic acid-polyurea copolymer (B) of 15% by mass. The polyamic acid-polyurea copolymer (B) had a number average molecular weight of 9,500 and a weight average molecular weight of 32,800.

[0097] <Comparative Synthesis Example 2> C-1 (9.12g, 46.0mmol), C-2 (8.36g, 34.5mmol), C-5 (14.3g, 34.8mmol) and NMP (179g) were added to a four-neck flask and stirred to completely dissolve the diamine. Next, B-1 (14.8g, 75.4mmol) and NMP (42.7g) were added and reacted at 25°C for 1.5 hours. Then, B-2 (7.52g, 34.5mmol) and NMP (81.8g) were added and reacted for another 17 hours to obtain a solution with a polyamic acid (C) concentration of 15% by mass. The number average molecular weight of this polyamic acid (C) was 9,600 and the weight average molecular weight was 23,000.

[0098] <Example 1> NMP and BCS were added to the solution of polyamic acid-polyurea copolymer (A) obtained in Synthesis Example 1 and stirred to obtain a liquid crystal alignment agent (1) having a polymer solid content of 3 mass%, NMP of 52 mass%, and BCS of 45 mass%. No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed to be a homogeneous solution.

[0099] <Comparative Examples 1 to 2> Liquid crystal alignment agents (2) and (3) were prepared in the same manner as in Example 1, except that a solution of polyamic acid-polyurea copolymer (B) and a solution of polyamic acid (C) were used instead of the solution of polyamic acid-polyurea copolymer (A).

[0100] <Example 2> The liquid crystal alignment agent (1) was mixed at 30% by mass with the liquid crystal alignment agent (3) at 70% by mass to obtain the liquid crystal alignment agent (4). No abnormalities such as turbidity or precipitation were observed in this liquid crystal alignment agent, and it was confirmed that it was a homogeneous solution.

[0101] <Comparative Example 3> A liquid crystal alignment agent (5) was prepared in the same manner as in Example 2, except that the liquid crystal alignment agent (2) was used instead of the liquid crystal alignment agent (1).

[0102] [Evaluation of pencil hardness] The liquid crystal alignment agent obtained in the examples and comparative examples was applied to a 30 mm x 40 mm ITO substrate by spin coating. It was then dried on a hot plate at 80°C for 1 minute and 30 seconds, and baked in a hot air circulating oven at 230°C for 20 minutes to obtain a substrate with a liquid crystal alignment film having a thickness of 100 nm. This substrate was measured by the pencil hardness test method (JIS K5400). The results are shown in Table 1. The higher the pencil hardness value, the higher the film hardness.

[0103] [Evaluation of surface energy] The contact angles of the liquid crystal alignment film-attached substrates obtained in the same manner as in the pencil hardness evaluation, using water and diiodomethane, were measured using a fully automatic contact angle meter (Kyowa Interface Science Co., Ltd., DMo-701). The surface energy of each liquid crystal alignment film was calculated using the contact angle results. The results are shown in Table 2. The lower the surface energy, the higher the liquid crystal alignment property.

[0104] [Table 1] In the table, the numerical values ​​in parentheses in the polymer composition indicate the blending ratio (parts by mass) of each polymer relative to 100 parts by mass of the total polymer components used in the preparation of the liquid crystal alignment agent.

[0105] [Table 2] In the table, the numerical values ​​in parentheses in the polymer composition indicate the blending ratio (parts by mass) of each polymer relative to 100 parts by mass of the total polymer components used in the preparation of the liquid crystal alignment agent.

[0106] As shown in Tables 1 and 2, the liquid crystal alignment agents of Examples 1 and 2, which contain a polyamic acid-polyurea copolymer obtained by using an aromatic diamine (a) and not using an aliphatic diamine, were able to give liquid crystal alignment films excellent in film hardness and liquid crystal alignment property, compared with the liquid crystal alignment agents of Comparative Examples 1 to 3.

[0107] The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2020-060312, filed on March 30, 2020, are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims

1. A liquid crystal aligning agent comprising the following component (A): Component (A): at least one polymer (A) selected from the group consisting of a polyimide precursor-polyurea copolymer having a repeating unit represented by the following formula (m1) and a repeating unit represented by the following formula (1), and an imidized polymer thereof, wherein at least one of the repeating unit represented by formula (m1) and the repeating unit represented by formula (1) is derived from an aromatic diamine (a) having any of the structures represented by the following formulas (S1) to (S2), the polymer (A) is obtained without using an aliphatic diamine, and the aromatic diamine (a) is a diamine represented by the following formula (d1) or formula (d2): 【Chemistry 1】 (X １ represents a tetravalent organic group. １ represents a divalent organic group derived from an aromatic diamine. １ each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. １ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkenyl group having 2 to 10 carbon atoms which may have a substituent, an alkynyl group having 2 to 10 carbon atoms which may have a substituent, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group. 【Chemistry 2】 (A １ is a divalent organic group derived from an aromatic diisocyanate, A ２ is a divalent organic group derived from an aromatic diamine, C １ and C ２ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 【Chemistry 3】 (X １ and X ２ each independently represents a single bond, -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -O-, -COO-, -OCO- or -((CH ２ ) ａ１ -A １１ ) ｍ１ In this case, a1 is an integer from 1 to 15, and A １１ represents an oxygen atom or -COO-; m １ is an integer from 1 to 2. １ and G ２ each independently represents a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms and a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted. m and n are each independently an integer of 0 to 3, and m+n is 1 to 6. R １ 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; R １ Any hydrogen atom forming X may be substituted with a fluorine atom. １ , X ２ , G １ , G ２ , a1 and A １１ If there are multiple Xs, there are multiple Xs. １ , X ２ , G １ , G ２ , a1 and A １１ are each independently defined as above.) 【Chemistry 4】 (X ２ａ is -CONH-, -NHCO-, -O-, -CH ２ represents -O-, -COO- or -OCO-. ２ represents a structure having a steroid skeleton.) 【Chemistry 5】 (X represents a divalent organic group selected from a single bond, -O-, -C(CH3)2-, -NH-, -CO-, -(CH2)m-, -SO2-, -O-(CH2)m-O-, -O-C(CH3)2-, -CO-(CH2)m-, -NH-(CH2)m-, -SO2-(CH2)m-, -CONH-(CH2)m-, -CONH-(CH2)m-NHCO-, and -COO-(CH2)m-OCO-. m is an integer of 1 to 8. Y represents any of the structures represented by formulae (S1) and (S2). In formula (d2), the two Ys may be the same or different.)

2. The liquid crystal aligning agent according to claim 1 , further comprising a component (B). Component (B): at least one polymer selected from the group consisting of polyimide precursors and imidized polymers thereof, which is different from polymer (A).

3. The formula (S1) to (S2) represent any one of structures selected from structures represented by the following formulas (S1-1) to (S1-7) and (S2-a). The liquid crystal aligning agent according to claim 1 or 2. 【Chemistry 6】 (In the formula, R １ 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. ｐ is -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CO-N(CH ３ )-, -NH-, -O-, -CH ２ O-, -CH ２ represents -OCO-, -COO-, or -OCO-. １１ represents an oxygen atom or -COO-* (wherein the bond marked with "*" is (CH ２ ) ａ２ (combines with), A ２ represents an oxygen atom or *-COO- (where the bond marked with "*" is (CH ２ ) ａ２ and a １ , a ３ are each independently an integer of 0 or 1; ２ is an integer from 1 to 10, and Cy represents a 1,4-cyclohexylene group or a 1,4-phenylene group. 【Chemistry 7】 (wherein X is a group represented by formula (X1), formula (X2) or -CH ２ O-, Col represents the formula (Col-1), the formula (Col-2) or the formula (Col-3), and G represents the formula (G1), the formula (G2), the formula (G3) or the formula (G4).

4. In the formula (1), A １ The liquid crystal aligning agent according to any one of claims 1 to 3, wherein is a divalent aromatic group having 6 to 30 carbon atoms and at least one benzene ring.

5. The polymer (B) is at least one polymer selected from the group consisting of a polyimide precursor having a repeating unit represented by the following formula (m2) and an imidized polymer thereof. The liquid crystal aligning agent according to any one of claims 2 to 4. 【Chemistry 8】 (X ２ represents a tetravalent organic group. ２ represents a divalent organic group. ２ , Z ２ are R in formula (m1), １ , Z １ and two R ２ , Z ２ may be the same or different.)

6. The liquid crystal aligning agent according to any one of claims 2 to 5, wherein the polymer (B) does not have a repeating unit represented by the formula (1).

7. At least one of the polymers (A) and (B) is obtained using a tetracarboxylic acid component containing a tetracarboxylic dianhydride represented by the following formula (3) or a derivative thereof. The liquid crystal aligning agent according to any one of claims 1 to 6. 【Chemistry 9】 (X represents a structure selected from the group consisting of the following (x-1) to (x-13).) 【Chemistry 10】 (R 1 to R 4 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 containing 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. R 5 and R 6 each independently represent a hydrogen atom or a methyl group. j and k are integers of 0 or 1. A 1 and A 2 each independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or an amide group. *1 is a bond bonding to one acid anhydride group, and *2 is a bond bonding to the other acid anhydride group. In formula (x-13), the two A 2 s may be the same or different from each other.)

8. The liquid crystal aligning agent described in any one of claims 1 to 7, wherein the polymer (A) is obtained using an aromatic diamine having at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocycle (excluding imide rings possessed by polyimide), a secondary amino group, and a tertiary amino group.

9. The liquid crystal aligning agent described in any one of claims 2 to 8, wherein the polymer (B) is obtained using a diamine having at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocycle (excluding imide rings possessed by polyimide), a secondary amino group, and a tertiary amino group.

10. A liquid crystal aligning agent described in any one of claims 2 to 9, wherein the content ratio of the (A) component and the (B) component is 10 / 90 to 90 / 10 in terms of a mass ratio of [(A) component] / [(B) component].

11. A liquid crystal alignment film formed using the liquid crystal alignment agent according to any one of claims 1 to 10.

12. A liquid crystal display element having a liquid crystal alignment film as described in claim 11.

13. A method for manufacturing a liquid crystal display element, comprising applying a liquid crystal alignment agent described in any one of claims 1 to 10 onto a pair of substrates having conductive films to form coating films, arranging the coating films opposite each other with a layer of liquid crystal molecules interposed therebetween to form a liquid crystal cell, and irradiating the liquid crystal cell with light while a voltage is applied between the conductive films of the pair of substrates.

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