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

Abstract

The present invention provides: a liquid crystal aligning agent which enables the formation of a liquid crystal alignment film that has high refractive index but does not have coloring properties, thereby having high light transmittance; a liquid crystal alignment film which is obtained from this liquid crystal aligning agent; and a liquid crystal display element which comprises this liquid crystal alignment film.　A liquid crystal aligning agent which is characterized by containing the component (A) and the component (B) described below.　Component (A): At least one polymer (A) that is selected from the group consisting of polyimide precursors which are obtained using a diamine component that contains a diamine (a) having at least one structure selected from the group consisting of structures represented by formulae (S1) to (S3) and polyimides which are imidized products of the polyimide precursors.　Component (B): At least one polymer (B) that is selected from the group consisting of polyimide precursors which are obtained using a diamine component that contains a diamine (b) represented by formula (2) and polyimides which are imidized products of the polyimide precursors. (In the formula (S1), each of X1 and X2 represents a single bond, -(CH2)a- (wherein a represents an integer from 1 to 15), or the like; each of G1 and G2 represents a divalent aromatic group having from 6 to 12 carbon atoms, or the like; each of m and n represents a number from 0 to 3; and R1 represents an alkyl group having from 1 to 20 carbon atoms, or the like.) (In the formula (S2), X3 represents a single bond, -CONH- or the like; and R2 represents an alkyl group having from 1 to 20 carbon atoms, or the like.) (In the formulae (S3), X4 represents –CONH-, -NHCO- or the like; and R3 represents a structure having a steroid skeleton.) (In the formula (2), each of A1 and A2 represents a divalent monocyclic group or fused ring group, and at least one of the A1 and A2 represents a divalent fused ring group; L represents a single bond or a divalent organic group; and each of m and n represents a number from 1 to 3.)

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 the liquid crystal molecules used, and various display elements such as TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, VA (Vertical Alignment) type, IPS type (In-Plane Switching), and FFS (fringe field switching) type are known. A liquid crystal display element is generally constructed by arranging a pair of electrode substrates facing each other with a predetermined gap (several μm) and sealing liquid crystal between the electrode substrates. Display on the liquid crystal display element is performed by applying a voltage between the transparent conductive films constituting the electrodes of the electrode substrates. In addition, these liquid crystal display elements have a liquid crystal alignment film for orienting the liquid crystal molecules. Known materials for the liquid crystal alignment film include, for example, polyamic acid, polyamic acid ester, polyimide, polyamide, etc. (see Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 080458 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the above-mentioned transparent conductive film in a liquid crystal display element is usually formed of a composition (ITO) in which indium oxide is the main component and is doped with a few percent of tin oxide, and the refractive index of the film is different from that of the liquid crystal alignment film and has a high value. Therefore, when light from a display light source is transmitted through the electrode substrate, the light is reflected at the interface between the transparent conductive film and the liquid crystal alignment film in each electrode substrate. As a result, the light transmittance of the electrode substrate cannot be sufficiently obtained, leading to a problem of a decrease in display brightness. In particular, ultra-high definition panels such as 4K and 8K have been developed in recent years, but these panels require a large occupancy rate of black matrix (BM) and TFT, etc., which reduces the aperture ratio of the panel, so improving the transmittance of the display area is becoming important.

[0005] Therefore, the present inventors have investigated various materials for forming the liquid crystal alignment film in order to increase the refractive index of the liquid crystal alignment film, from the viewpoint that the above-mentioned problems can be solved by reducing the difference between the refractive index of the transparent conductive film and the refractive index of the liquid crystal alignment film. Specifically, in order to increase the refractive index of the liquid crystal alignment film, various types of polymers to be contained in the liquid crystal alignment agent forming the liquid crystal alignment film have been searched for.

[0006] As a result, by selecting a specific polymer, it was possible to obtain a liquid crystal alignment film having a high refractive index close to that of the transparent conductive film, but on the other hand, it was revealed that the polymer forming the liquid crystal alignment film having a high refractive index is often colored. The liquid crystal alignment film formed from the liquid crystal alignment agent containing the colored polymer has a low light transmittance, which leads to a decrease in display brightness, and as a result, the above-mentioned object is not achieved.

[0007] In view of the above circumstances, an object of the present invention is to provide a liquid crystal alignment agent that forms a liquid crystal alignment film having a high refractive index while not being colored and therefore having high light transmittance, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film. [Means for solving the problem]

[0008] As a result of intensive research into achieving the above object, the present inventors have found that a liquid crystal aligning agent containing two or more polymers having specific structures, some of which include a novel polymer, is effective for achieving the above object, and have thus completed the present invention.

[0009] The present invention relates to a liquid crystal aligning agent characterized by containing the following components (A) and (B), a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display device having the liquid crystal alignment film. Component (A): At least one polymer (A) selected from the group consisting of polyimide precursors obtained using a diamine component containing at least one diamine (a) selected from the group consisting of structures represented by the following formulae (S1) to (S3), and polyimides which are imidized products of the polyimide precursors: Component (B): at least one polymer (B) selected from the group consisting of polyimide precursors obtained by using a diamine component containing diamine (b) represented by the following formula (2) and polyimides which are imidized products of the polyimide precursors: [ka] (X 1 and X 2 are each independently a single bond, -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -COO-, -OCO- or -((CH2) a1 -A1) m1 - (a1 is an integer of 1 to 15, A1 represents an oxygen atom or -COO-, and m1 is an integer of 1 to 2. When m1 is 2, a1 and A1 each independently have the above definition). 1 and G 2each independently represents a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms or a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. m and n each independently represent 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 the formula (I) may be substituted with a fluorine atom. [ka] (X 3 represents a single bond, -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CHO-, -COO- or -OCO-. 2 represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms; R 2 Any hydrogen atom forming the formula (I) may be replaced with a fluorine atom. [ka] (X 4 represents -CONH-, -NHCO-, -O-, -CH2O-, -OCH2-, -COO- or -OCO-. 3 represents a structure having a steroid skeleton.) [ka] (A1 and A2 each independently represent a divalent monocyclic group or fused ring group which may have a substituent, and at least one of A1 and A2 represents a divalent fused ring group which may have a substituent. L represents a single bond, -COO-, -CO-S-, -CO-, -CONR- (wherein R represents a hydrogen atom or a monovalent alkyl group having 1 to 6 carbon atoms), -O-, -S- or a divalent organic group. m and n each independently represent an integer of 1 to 3.) Effect of the Invention

[0010] According to the present invention, a liquid crystal aligning agent is obtained that has a high refractive index but is not colored, and therefore forms a liquid crystal alignment film with high light transmittance. The liquid crystal alignment film on which such a liquid crystal aligning agent is formed can reduce the difference between the refractive index of the transparent conductive film in a liquid crystal display element and the refractive index of the liquid crystal alignment film, and since it is not colored, a liquid crystal display element with high light transmittance and high display brightness can be obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] As described above, the liquid crystal aligning agent of the present invention is characterized by containing the following components (A) and (B). (Component A: Polymer (A)) The component (A) in the present invention is at least one polymer (A) selected from the group consisting of polyimide precursors obtained by using a diamine component containing at least one diamine (a) selected from the group consisting of structures represented by the following formulae (S1) to (S3), and polyimides which are imidized products of the polyimide precursors. [ka]

[0012] In formula [S1], X 1 , X 2、 G 1 , G 2 , R 1 , m, and n are as defined above. In addition, G 1 , G 2 Examples of the divalent cyclic group in the formula (I) include a cyclopropylene group, a cyclohexylene group, and a phenylene group. Any hydrogen atom on these cyclic groups may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom.

[0013] [ka] In formula [S2], X 3 , R 2 The definition of is as described above. 2 From the viewpoint of improving the liquid crystal alignment property, the alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms is preferable.

[0014] [ka] In formula [S3], X 4 , R 3 The definition of is as described above. 3 is preferably a structure containing a cholestanyl group, a cholesteryl group or a lanostannyl group.

[0015] Preferred embodiments of formula [S1] include the following formulae [S1-x1] to [S1-x7]. [ka]

[0016] In the above formula, R 1 X is 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 is an oxygen atom or -COO-* (wherein the bond marked with "*" is (CH2)), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CHO-, -CHOCO-, -COO-, or -OCO-). A1 is an oxygen atom or -COO-* (wherein the bond marked with "*" is (CH2)). a2 A2 is an oxygen atom or *-COO- (where the bond marked with "*" is (CH2) a2 a3 is 0 or 1, a1 and a2 each independently represents an integer of 1 to 10, and Cy is 1,4-cyclohexylene or a 1,4-phenylene group. As a preferred embodiment of the formula [S2], X 3is any one of -O-, -CHO-, -COO-, or -OCO-, and R 2 is preferably an alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, and R 2 is more preferably an alkyl group having 3 to 20 carbon atoms, and R 2 Any hydrogen atom forming the formula (I) may be substituted with a fluorine atom.

[0017] A preferred embodiment of the above formula [S3] is the following formula [S3-x]. In the formula [S3-x], X is the formula [X1], the formula [X2] or the formula [X3], Col is the formula [Col1], the formula [Col2] or the formula [Col3], and G is the formula [G1], the formula [G2], the formula [G3] or the formula [G4]. Me represents a methyl group.

[0018] [ka]

[0019] As the diamine (a) having the structure represented by the above formulas (S1) to (S3), preferably, the diamine represented by the following formula [1] or formula [2] can be mentioned. [ka]

[0020] In the above formulas [1] and [2], Y represents a side chain structure represented by the above formulas [S1] to [S3], and the two Y's in the formula [2] may be the same or different. X represents 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-, -COO-(CH2) m-OCO-, -COO-, -CONH-, -NH-(CH2) m -NH- or -SO2-(CH2) m represents -SO2-, and m is an integer of 1 to 8.

[0021] Preferred examples of the diamine represented by the above formula [1] include the following formulae [S-1] to [S-18]. [ka] (n is an integer from 1 to 20.)

[0022] [ka]

[0023] Preferred examples of the diamine represented by the above formula [2] include structures selected from the group consisting of the following formulas [W-1] to [W-6]. [ka]

[0024] In the above formula, X p1 ~X p8 each independently represents X in the formulas [S1-x1] to [S1-x6] p X s1 ~X s4 Each independently represents -O-, -CH2O-, -OCH2-, -COO- or -OCO-. X a ~X f -O-, -NH-, -O-(CH2) m -O-, -C(CH3)2-, -CO-, -COO-, -CONH-, -(CH2) m -, -SO2-, -OC(CH3)2-, -CO-(CH2) m -, -NH-(CH2) m -, -NH-(CH2) m -NH-, -SO2-(CH2) m -, -SO2-(CH2) m -SO2-, -CONH-(CH2)m -, -CONH-(CH2) m -NHCO- or -COO-(CH2) m -OCO- indicates R 1a ~R 1h each independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. m is an integer of 1 to 8.

[0025] (B component: Polymer (B)) The component (B) in the present invention is at least one polymer (B) selected from the group consisting of polyimide precursors obtained by using a diamine component containing a novel diamine (b) represented by the following formula (2) and polyimides which are imidized products of the polyimide precursors: [ka] In the above formula (2), A1, A2, L, m and n are as defined above.

[0026] The monocyclic group in A1 and A2 refers to a divalent group obtained by removing two hydrogen atoms from a monocyclic ring. Examples of the monocyclic ring include benzene; 5-membered heterocyclic rings such as furan, thiophene, pyrrole, oxazole, thiazole, imidazole, and pyrazole; and 6-membered heterocyclic rings such as pyran, pyrone, pyridine, pyridazine, pyrimidine, and pyrazine. The monocyclic ring is preferably benzene or pyridine. When the monocyclic ring is benzene, the monocyclic group is a phenylene group.

[0027] The fused ring group in A1 and A2 refers to a divalent group obtained by removing two hydrogen atoms from a fused ring. Examples of the fused ring include fused polycyclic aromatic hydrocarbons such as naphthalene, tetralin, indene, fluorene, anthracene, phenanthrene, and pyrene; and fused polycyclic heterocycles such as benzofuran, thionaphthene, indole, carbazole, coumarin, benzo-pyrone, quinoline, isoquinoline, acridine, phthalazine, quinazoline, and quinoxaline. The fused ring is preferably any one of naphthalene, anthracene, pyrene, indole, carbazole, coumarin, benzo-pyrone, quinoline, and isoquinoline.

[0028] The monocyclic and fused ring groups in A1 and A2 may have a substituent. Examples of the substituent in the monocyclic and fused ring groups include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom.

[0029] Examples of the divalent organic group in L include a divalent chain hydrocarbon group having 1 to 20 carbon atoms, and a group in which at least one methylene group of the chain hydrocarbon group is replaced with -COO-, -COS-, -CO-, -CONR- (wherein R represents a hydrogen atom or a monovalent alkyl group having 1 to 6 carbon atoms), -O-, or -S-. The chain hydrocarbon group may be branched or linear, and may be saturated or unsaturated. Examples of the divalent chain hydrocarbon group having 1 to 20 carbon atoms include an alkanediyl group having 1 to 20 carbon atoms. From the viewpoint of achieving both a high refractive index and a high light transmittance, L is preferably a single bond, -(CH2) n - (n is an integer of 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6), -O-(CH2) n -O- (n is an integer of 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6), -O-(CH2) n - (n is an integer of 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6), -S-(CH2) n -S- (n is an integer of 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6), or -S-(CH2) n- (n is an integer of 1 to 20, more preferably 1 to 10, and further preferably 1 to 6). In the above formula (2), m and n for A1 and A2 are preferably 1 or 2.

[0030] Among them, the diamine (b) is preferably one represented by the following formulas (2-1) to (2-25). [ka] [ka]

[0031] (Production of Polymer (A) and Polymer (B)) The polymer (A) and the polymer (B) contained in the liquid crystal alignment agent of the present invention are polyimide precursors (A) and (B) obtained by using a diamine component containing the diamine (a) and a diamine component containing the diamine (b), respectively, or polyimides (A) and (B) which are imidized products of the polyimide precursors. Here, the polyimide precursor is a polymer from which a polyimide can be obtained by imidizing a polyamic acid, a polyamic acid ester, or the like. The polyamic acid (A), which is a polyimide precursor of the polymer (A), can be obtained by a polymerization reaction between a diamine component containing the diamine (a) and a tetracarboxylic acid component. In this case, the amount of diamine (a) used is preferably 1 mol % or more, more preferably 5 mol % or more, based on the diamine component to be reacted with the tetracarboxylic acid component. When a diamine other than diamine (a) is used in combination, the amount of diamine (a) used is preferably 99 mol % or less, more preferably 95 mol % or less.

[0032] The polyamic acid (B), which is a polyimide precursor of the polymer (B), can be obtained by a polymerization reaction between a diamine component containing the diamine (b) and a tetracarboxylic acid component. In this case, the amount of diamine (b) used is preferably 1 mol % or more, more preferably 2 mol % or more, based on the diamine component reacted with the tetracarboxylic acid component. When a diamine other than diamine (b) is used in combination, the amount of diamine (b) used is preferably 99 mol % or less, more preferably 95 mol % or less.

[0033] The diamine components used in the production of the polyamic acids (A) and (B) may each contain a diamine other than the diamine (a) and a diamine other than the diamine (b) (hereinafter, also referred to as other diamines). Examples of other diamines are given below, but the present invention is not limited thereto.

[0034] Diamines having a carboxy group such as p-phenylenediamine, m-phenylenediamine, 4-(2-(methylamino)ethyl)aniline, and 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylether, 3,3'-diaminodiphenylether, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 1,2-bis(4-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1,4-bis(4-amino phenyl)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)ethoxy) 2,2'-bis[4-(4-aminophenoxy)ethyl]ether, 4-amino-4'-(2-(4-aminophenoxy)ethoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 1,4-diaminonaphthalene, 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-aminophenoxy)ethyl)ether, diamines having a urea bond such as 1,3-bis(4-aminophenethyl)urea, diamines represented by the following formulas (a-1) to (a-6), preferably 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 radical initiation function such as those represented by the following formulas (R1) to (R5), 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, diamines having a heterocycle such as those represented by the following formulas (z-1) to (z-18), diamines having a diphenylamine skeleton such as those represented by the following formulas (Dp-1) to (Dp-3), diamines having an oxazoline structure such as those represented by the following formulas (Ox-1) to (Ox-2), organosiloxane-containing diamines such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and diamines described in WO 2016 / 125870.

[0035] [ka]

[0036] [ka]

[0037] [ka] (d1 represents an integer from 2 to 10.)

[0038] [ka] (n represents an integer from 2 to 10.)

[0039] [ka] [ka]

[0040] The 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 the polyamic acids (A) and (B), in order to increase the response speed of a liquid crystal display element using a PSA mode or an SC-PVA mode.

[0041] As the other 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-3), and diamines represented by the above formulas (Ox-1) to (Ox-2) are preferred.

[0042] The amount of the other diamines used is preferably 1 to 99 mol %, more preferably 1 to 95 mol %, and even more preferably 5 to 95 mol %, based on the total diamine components used when producing polyamic acid (A).The amount of the other diamines used is preferably 1 to 99 mol %, more preferably 2 to 99 mol %, and even more preferably 2 to 98 mol %, based on the total diamine components used when producing polyamic acid (B).

[0043] In addition, when producing the polyamic acids (A) and (B), at least one diamine represented by the following formula (5) can be used in order to improve the solvent solubility of the polymer in the liquid crystal alignment agent and to increase the voltage retention rate of the resulting liquid crystal alignment film. [ka]

[0044] Here, Y1 represents a divalent organic group having a structure represented by the following formula (6). [ka] In formula (6), D represents a protecting group which is eliminated by heating and is replaced with a hydrogen atom, and * represents a connection site with another structure. A preferred structure for D is a tert-butoxycarbonyl group. Preferred specific examples of the diamine represented by formula (5) are given below, in which Boc represents a tert-butoxycarbonyl group.

[0045] [ka]

[0046] When the diamine represented by formula (5) is used, the amount of the diamine represented by formula (5) used is preferably 1 to 50 mol %, more preferably 5 to 40 mol %, based on the total diamine components used, regardless of whether the polyamic acid (A) or (B) is produced.

[0047] (Tetracarboxylic acid component) In producing the above polyamic acids (A) and (B), the tetracarboxylic acid component to be reacted with the diamines (a) and (b) may be not only a tetracarboxylic acid dianhydride but also a derivative of a tetracarboxylic acid dianhydride, such as a tetracarboxylic acid, a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester, or a tetracarboxylic acid dialkyl ester dihalide.

[0048] The tetracarboxylic dianhydride or derivative thereof may be an aromatic tetracarboxylic dianhydride, an aliphatic tetracarboxylic dianhydride, an alicyclic tetracarboxylic dianhydride, or a derivative thereof. Here, the aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to an aromatic ring. The aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups bonded to a chain hydrocarbon structure. However, it is not necessary to be composed of only a chain hydrocarbon structure, and it may have an alicyclic structure or an aromatic ring structure in part. The alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to an alicyclic structure. However, none of these four carboxy groups are bonded to an aromatic ring. In addition, it is not necessary to be composed of only an alicyclic structure, and it may have a chain hydrocarbon structure or an aromatic ring structure in part. Of the above tetracarboxylic dianhydrides or derivatives thereof, tetracarboxylic dianhydrides or derivatives thereof represented by the following formula (3) are preferred. [ka] In the formula (3), X represents a structure selected from the group consisting of the following (x-1) to (x-13):

[0049] [ka]

[0050] In the above formula (x-1), R 1 ~R 4 R each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom, or a phenyl group. 5 and R 6Each of j and k is independently 0 or 1, and A1 and A2 are independently a single bond, an ether (-O-), a carbonyl (-CO-), an ester (-COO-), a phenylene, a sulfonyl group (-SO2-), or an amide group (-CONH-), and two A2 may be the same or different. *1 is a bond bonded to one acid anhydride group, and *2 is a bond bonded to the other acid anhydride group.

[0051] 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]

[0052] 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.

[0053] The proportion of the tetracarboxylic dianhydride represented by the above formula (3) or its derivative used, in either case of the polyamic acid (A) or (B), is preferably 1 mol % or more, more preferably 5 mol % or more, and even more preferably 10 mol % or more, per mol of the tetracarboxylic acid component used. The tetracarboxylic acid component used in the production of the polyamic acids (A) and (B) may contain a tetracarboxylic dianhydride other than that of the above formula (3) or a derivative thereof.

[0054] The polyamic acids (A) and (B) are produced by reacting a diamine component containing a diamine (a) or a diamine (b) with a tetracarboxylic acid component in a solvent (condensation polymerization). The solvent is not particularly limited as long as the produced polymer is soluble in the solvent. Specific examples of the solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, and 1,3-dimethyl-2-imidazolidinone. In addition, when the polymer has high solubility in the solvent, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the solvents represented by the following formulas [D-1] to [D-3] can be used.

[0055] [ka] (In formula [D-1], D 1 represents an alkyl group having 1 to 3 carbon atoms, and in formula [D-2], D 2 represents an alkyl group having 1 to 3 carbon atoms, and in formula [D-3], D 3 represents an alkyl group having 1 to 4 carbon atoms).

[0056] These solvents may be used alone or in combination. Furthermore, even if the solvent does not dissolve the polymer, it may be mixed with the above-mentioned solvent to the extent that the produced polymer does not precipitate.

[0057] When the diamine component and the tetracarboxylic acid component are reacted in a solvent, the reaction can be carried out at any concentration, but the concentration of the diamine component and the tetracarboxylic acid component in the solvent 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 the solvent can be added. In the reaction, the ratio of the total number of moles of the tetracarboxylic acid components to the total number of moles of the diamine components (total number of moles of the diamine components / total number of moles of the tetracarboxylic acid components) is preferably 0.8 to 1.2. As in the case of a normal polycondensation reaction, the closer this molar ratio is to 1.0, the higher the molecular weight of the specific polymer produced.

[0058] The polyamic acid ester, which is a polyimide precursor, can be obtained by a known method such as, for example, [I] a method of reacting the polyamic acid obtained by the above synthesis reaction with an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester with a diamine, or [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine.

[0059] [Polyimide] The polyimide contained in the liquid crystal alignment agent of the present invention is polyimide (A) or (B) obtained by ring-closing the above-mentioned polyimide precursor. In the polyimide, the ring-closing rate of the amic acid group (also called the imidization rate) does not necessarily have to be 100% and can be adjusted arbitrarily.

[0060] Methods for obtaining polyimides (A) and (B) by imidizing the polyimide precursor include thermal imidization in which a solution of the polyimide precursor is heated as is, and catalytic imidization in which a catalyst is added to a solution of the polyimide precursor. When the polyimide precursor is thermally imidized in a solution, the temperature is 100 to 400°C, preferably 120 to 250°C, and it is preferable to carry out the thermal imidization while removing water generated by the imidization reaction from the system.

[0061] The catalytic imidization of the polyimide precursor can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring at -20 to 250°C, preferably 0 to 180°C. The amount of the basic catalyst is 0.5 to 30 times by mole, preferably 2 to 20 times by mole, the amount of the acid anhydride is 1 to 50 times by mole, preferably 3 to 3 ... When recovering the polyimide produced from the reaction solution of imidization of the polyimide precursor, the reaction solution may be poured into a solvent to cause 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 room temperature or by heating under normal or reduced pressure. In addition, the polymer precipitated and recovered can be redissolved in a solvent and the reprecipitation and recovery operation can be repeated 2 to 10 times to reduce impurities in the polymer. Examples of the solvent in this case include alcohols, ketones, and hydrocarbons, and it is preferable to use three or more solvents selected from these because the efficiency of purification is further improved.

[0062] The polystyrene-equivalent weight average molecular weight (Mw) of the polyimide precursor and polyimide measured by gel permeation chromatography (GPC) is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. The molecular weight distribution (Mw / Mn), which is expressed as the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC, is preferably 15 or less, more preferably 10 or less. With the molecular weight in this range, good alignment properties of liquid crystal display elements can be ensured.

[0063] (Liquid crystal alignment agent) The liquid crystal aligning agent of the present invention is a liquid composition obtained by dispersing or dissolving the polymer (A), the polymer (B), and other components used as necessary, preferably in a suitable solvent. The polymer (A) and the polymer (B) contained in the liquid crystal aligning agent of the present invention preferably have a mass ratio ((A) / (B)) of the content of the (A) component to the content of the (B) component of 5 / 95 to 80 / 20, more preferably 10 / 90 to 60 / 40. This makes it possible to provide a liquid crystal alignment film having a higher light transmittance while maintaining the surface properties such as liquid crystal alignment required for the liquid crystal alignment film.

[0064] In the liquid crystal aligning agent of the present invention, in addition to the polymers (A) and (B), other polymers (hereinafter also referred to as other polymers) may be contained, for example, for the purpose of improving electrical properties or solution properties.

[0065] The main skeleton of the other polymer is not particularly limited, and examples thereof include the main skeletons of polyimide precursors, polyimides, polysiloxanes, polyesters, polyamides, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-phenylmaleimide) derivatives, poly(meth)acrylates, etc. Among them, at least one selected from the group consisting of polyimide precursors, polyimides, polyamides, polyorganosiloxanes, poly(meth)acrylates, and polyesters is preferable, and at least one selected from the group consisting of polyimide precursors, polyimides, and polysiloxanes is more preferable. The other polymers may be used in combination of two or more kinds.

[0066] The liquid crystal aligning agent of the present invention may contain other components as necessary. Examples of the components include at least one compound selected from the group consisting of crosslinkable compounds having at least one substituent selected from an epoxy group, an isocyanate group, an oxetanyl group, a cyclocarbonate group, a blocked isocyanate group, a hydroxy group, and an alkoxy group, and crosslinkable compounds having a polymerizable unsaturated group, a functional silane compound, a metal chelate compound, a curing accelerator, a surfactant, an antioxidant, a sensitizer, a preservative, and a compound for adjusting the dielectric constant or electrical resistance of the liquid crystal alignment film. Specific examples of preferred crosslinkable compounds include compounds represented by the following formulas (CL-1) to (CL-11). Examples of compounds for adjusting the dielectric constant or electrical resistance of the liquid crystal alignment film include monoamines having a nitrogen-containing aromatic heterocycle such as 3-picolylamine. [ka]

[0067] Examples of the organic solvent used in the liquid crystal aligning agent of the present invention include N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone. , 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, ethylene glycol monomethyl ether Examples of the ethylene glycol monomethyl ether include ethylene glycol monoethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, diisobutyl carbinol (2,6-dimethyl-4-heptanol), diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, and propylene carbonate. These can be used in a mixture of two or more kinds.

[0068] The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., and is preferably 1 to 10 mass%. From the viewpoint of forming a uniform and defect-free coating film, it is preferably 1 mass% or more, and from the viewpoint of storage stability of the solution, it is preferably 10 mass% or less, and particularly preferably 2 to 8 mass%.

[0069] <Liquid crystal alignment film> A liquid crystal alignment film for vertical alignment using the liquid crystal alignment agent of the present invention can be produced by sequentially carrying out the steps of applying the above-mentioned liquid crystal alignment agent on a substrate, drying and baking, and, if necessary, carrying out an alignment treatment such as a rubbing treatment or light irradiation. The substrate used in this case is not particularly limited as long as it is a highly transparent substrate, and in addition to a glass substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate can also be used. From the viewpoint of simplifying the process, it is preferable to use a substrate on which an ITO electrode or the like for driving the liquid crystal is formed. In addition, in a reflective liquid crystal display element, an opaque substrate such as a silicon wafer can be used for only one substrate, and in this case, a light-reflecting material such as aluminum can also be used for the electrode.

[0070] Examples of the method for applying the liquid crystal alignment agent include screen printing, offset printing, flexographic printing, inkjet method, dip method, roll coater method, slit coater method, spinner method, spray method, etc., but from the viewpoint of improving the production efficiency of the liquid crystal alignment film, a method of applying the agent by flexographic printing or inkjet method is preferred.

[0071] After the liquid crystal alignment agent is applied onto the substrate, it is dried by a heating means such as a hot plate, a heat circulation oven, or an IR (infrared) oven, preferably at 40 to 150°C depending on the solvent used in the liquid crystal alignment agent, and then baked at a temperature of preferably 150 to 300°C, more preferably 180 to 250°C, to achieve liquid crystal alignment. The thickness of the liquid crystal alignment film after baking is preferably 5 to 300 nm, more preferably 10 to 100 nm, since if it is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may decrease.

[0072] <Liquid crystal display element> The liquid crystal display element of the present invention comprises the above-mentioned liquid crystal alignment film.

[0073] When the display mode of the liquid crystal display element to be manufactured is the VA type, the coating film formed as described above can be used as a liquid crystal alignment film as it is, but if necessary, it may be subjected to a rubbing treatment or a PSA treatment described later. On the other hand, when the display mode of the liquid crystal display element to be manufactured is the vertical electric field mode other than the VA type or the horizontal electric field mode, the formed coating surface is subjected to an alignment treatment by rubbing treatment or irradiation with polarized ultraviolet light, etc.

[0074] The liquid crystal aligning agent of the present invention is also preferably used for a liquid crystal display element manufactured through a process in which a liquid crystal layer is provided between a pair of substrates equipped with electrodes, a liquid crystal composition containing a polymerizable compound that is polymerized by at least one of active energy rays and heat is placed between the pair of substrates, and the polymerizable compound is polymerized by at least one of irradiation with active energy rays and heating while applying a voltage between the electrodes. Here, the voltage applied can be, for example, a direct current or alternating current of 5 to 50 V. Moreover, ultraviolet rays are suitable as the active energy rays. The ultraviolet rays include ultraviolet rays having a wavelength of 300 to 400 nm, preferably ultraviolet rays having a wavelength of 310 to 360 nm. The amount of light irradiation is preferably 0.1 to 20 J / cm. 2 and more preferably 1 to 20 J / cm 2 It is.

[0075] A method for manufacturing a liquid crystal display element using the liquid crystal alignment agent of the present invention includes, for example, a method in which the liquid crystal alignment agent is applied to a pair of substrates having conductive films to form coating films, the coating films are arranged facing each other with a layer of liquid crystal molecules interposed therebetween to form a liquid crystal cell, and the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates.

[0076] The above liquid crystal display element controls the pretilt of liquid crystal molecules by the PSA (Polymer Sustained Alignment) method. In the PSA method, a small amount of a photopolymerizable compound, for example, a photopolymerizable monomer, is mixed into the liquid crystal material, and after assembling a liquid crystal cell, the photopolymerizable compound is irradiated with ultraviolet light or the like while a predetermined voltage is applied to the liquid crystal layer, and the pretilt of the liquid crystal molecules is controlled by the generated polymer. Since the alignment state of the liquid crystal molecules when the polymer is generated is stored even after the voltage is removed, the pretilt of the liquid crystal molecules can be adjusted by controlling the electric field formed in the liquid crystal layer. In addition, the PSA method does not require a rubbing process, so it is suitable for forming a vertical alignment type liquid crystal layer in which it is difficult to control the pretilt by a rubbing process.

[0077] The liquid crystal display element of the present invention is obtained by obtaining a substrate with a liquid crystal alignment film from the liquid crystal aligning agent of the present invention by the above-mentioned method, and then producing a liquid crystal cell by a known method to obtain a liquid crystal display element. Examples of methods for producing a liquid crystal cell include a method of preparing a pair of substrates on which a liquid crystal alignment film has been formed, spraying spacers onto the liquid crystal alignment film of one of the substrates, bonding the other substrate to the other substrate with the liquid crystal alignment film surface facing inward, and injecting liquid crystal under reduced pressure to seal the cell, and a method of dropping liquid crystal onto the liquid crystal alignment film surface on which the spacers have been sprayed, and then bonding the substrates together to seal the cell.

[0078] As described above, the liquid crystal may be mixed with a polymerizable compound that is polymerized by ultraviolet irradiation or heat. Examples of the polymerizable compound include compounds having one or more polymerizable unsaturated groups, such as acrylate groups or methacrylate groups, in the molecule, such as the polymerizable compounds represented by the following formulas (M-1) to (M-3).

[0079] [ka]

[0080] In this case, the content of the polymerizable compound is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the liquid crystal component. If the content of the polymerizable compound is less than 0.01 part by mass, the polymerizable compound does not polymerize and the alignment of the liquid crystal cannot be controlled, and if it is more than 10 parts by mass, the amount of unreacted polymerizable compound increases, and the image sticking characteristic of the liquid crystal display element decreases. After the liquid crystal cell is produced, the polymerizable compound is polymerized by applying heat or ultraviolet light to the liquid crystal cell while applying an AC / DC voltage to the liquid crystal cell. This makes it possible to control the alignment of the liquid crystal molecules.

[0081] The liquid crystal alignment agent of the present invention may also be used in a liquid crystal display element, i.e., an SC-PVA mode, which is manufactured by a process of having a liquid crystal layer between a pair of substrates equipped with electrodes, disposing a liquid crystal alignment film containing a polymerizable group that is polymerized by at least one of active energy rays and heat between the pair of substrates, and applying a voltage between the electrodes. Here, ultraviolet rays are suitable as the active energy rays. As the ultraviolet rays, the ultraviolet rays used in the PSA method can be used, including the preferred embodiment. In the case of polymerization by heating, the heating temperature is 40 to 120°C, preferably 60 to 80°C. Moreover, ultraviolet rays and heating may be performed simultaneously.

[0082] In order to obtain a liquid crystal alignment film containing a polymerizable group that is polymerized by at least one of active energy rays and heat, a method of adding a compound containing this polymerizable group to a liquid crystal alignment agent, or a method of using a polymer component containing a polymerizable group can be mentioned. A specific example of a polymer containing a polymerizable group is a polymer obtained by using the above-mentioned diamine having a function of being polymerized by irradiation with light. EXAMPLES

[0083] The present invention will be described in more detail below by way of examples, but the present invention should not be construed as being limited to these examples. In the following, the abbreviations of the compounds, the methods for measuring the respective properties, and the methods for preparing the measurement samples etc. are as follows. Unless otherwise specified, the numerical values ​​and numerical ratios are based on mass.

[0084] <Diamine (a)> [ka]

[0085] <Diamine (b)> [ka]

[0086] <Other diamines> [ka] (Boc represents a tert-butoxycarbonyl group.)

[0087] (Tetracarboxylic acid dianhydride) [ka]

[0088] (Organic solvent) NMP: N-methyl-2-pyrrolidone, BCS: Butyl cellosolve THF: tetrahydrofuran;

[0089] [viscosity] The viscosity of the polyamic acid solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample amount of 1.1 mL (milliliters), a cone rotor TE-1 (1°34', R24), and a temperature of 25°C.

[0090] [Molecular weight measurement] The molecular weights of the polyimide precursor and polyimide were measured using a room temperature gel permeation chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko K.K.) and columns (KD-803, KD-805) (manufactured by Shodex Co., Ltd.) as follows. Column temperature: 50℃ Eluent: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, phosphoric acid anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 ml / L) Flow rate: 1.0ml / min Standard samples for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000, and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: approximately 12,000, 4,000, and 1,000) (manufactured by Polymer Laboratory Co., Ltd.).

[0091] [Measurement of imidization rate] 20 mg of polyimide powder was placed in an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube standard, φ5 (Kusano Scientific Co., Ltd.)), deuterated dimethyl sulfoxide (DMSO-d6, 0.05 mass% TMS (tetramethylsilane) mixture) (0.53 ml) was added, and ultrasonic waves were applied to completely dissolve the powder. This solution was measured by 500 MHz proton NMR using an NMR measurement device (JNW-ECA500) (JEOL Datum Co., Ltd.). The imidization rate was calculated by the following formula using the proton peak integrated value of this proton and the proton peak integrated value of the proton peak derived from the NH group of the amic acid that appears around 9.5 to 10.0 ppm. Imidization rate (%) = (1-α·x / y) × 100 In the above formula, x is the integrated value of the proton peak derived from the NH group of the amic acid, y is the integrated value of the peak of the reference proton, and α is the ratio of the number of reference protons to one NH group proton of the amic acid in the case of polyamic acid (imidization rate 0%).

[0092] <Synthesis of diamine DA-v-7> Compound [DA-v-7] was synthesized according to the following scheme, where "MeO" represents a methoxy group. [ka]

[0093] (Synthesis of compound 3 (mixture of 3a and 3b)) Magnesium (15.39 g, 63.3 mmol, 1.5 eq.) was added to a four-neck flask, and vacuum drying was performed for 1 hour using a vacuum pump. THF (100 g) was then added using a syringe, and the mixture was stirred at room temperature. Next, a solution of compound 1 (100 g, 42.2 mmol) in THF (300 g) was gradually added dropwise at a rate of gentle reflux. The reaction solution was then cooled to 0°C, and a solution of compound 2 (105.60 g, 42.2 mmol, 1.0 eq.) in THF (200 g) was added dropwise. After the dropwise addition was completed, the temperature of the reaction solution was returned to room temperature, and the mixture was stirred at room temperature for 3 hours. Then, toluene (1 L) was added to dilute the reaction solution, and the reaction solution was cooled again to 0°C, and 10% acetic acid solution (500 g) was gradually added dropwise. Next, the aqueous layer was removed by a separation operation, and the organic layer was washed with saturated saline (1 L), saturated aqueous sodium bicarbonate (1 L), and saturated saline (1 L), respectively, and the organic layer was dried over anhydrous magnesium sulfate. Then, filtration and distillation were performed using an evaporator to obtain 172 g of crude crystals of compound 3. The obtained crude crystals were used as they were in the next reaction.

[0094] (Synthesis of compound 4) A mixture of crude crystals of compound 3 (172 g, 422 mmol) and p-toluenesulfonic acid monohydrate (4.82 g, 25.3 mmol, 0.06 eq.) in dehydrated toluene (MS4A dehydrated product, 2 L) was reacted for 2 hours under reflux while removing water. After the reaction was completed, about half of the amount of toluene used was distilled off using an evaporator, and the solution was stirred at room temperature to precipitate a solid. The obtained solid was filtered to obtain crystals of compound 4 (yield 150 g, yield 91%).

[0095] (Synthesis of compound 5 (5a, 5b mixture)) A mixture of compound 4 (108 g, 276 mmol), 5% palladium carbon (wet product, 11 g, 10 wt%), ethyl acetate (1 L), and ethanol (1 L) was stirred at room temperature in the presence of hydrogen. After the reaction was completed, toluene (2 L) was added to dissolve the crystals, and the reaction mixture was filtered through Celite, and the Celite was washed with 1 L of toluene. The filtrate was concentrated under reduced pressure to obtain the target compound 5 (yield: 103.3 g, yield: 95%).

[0096] (Synthesis of compound 6) At 0°C under nitrogen substitution, BBr3 (1.0M-CH2Cl2, 243mL, 1.01mol) was added dropwise to a solution of compound 5 (95.4g, 243mmol) in methylene chloride (800mL). After the addition, the mixture was stirred at 0°C for 2 hours. After the reaction was completed, the reaction solution was added little by little to distilled water. Extraction was performed with ethyl acetate (1L), and the extract was washed twice with 500mL of distilled water. The organic layer was dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The obtained crude product was recrystallized with ethanol, filtered, and washed with ethanol to obtain the target compound 6 (yield 18.6g, yield 21%).

[0097] (Synthesis of compound 8) A solution of compound 7 (5.35 g, 26.4 mmol) in toluene (20 g) was added dropwise to a mixture of compound 6 (10.0 g, 26.4 mmol), potassium carbonate (11.0 g, 79.2 mmol, 3 eq.) and toluene (50 g) under reflux. After the addition, the mixture was stirred overnight at reflux. After the reaction was completed, the reaction solution was cooled to about 60°C, ethyl acetate (500 g) was added, and the mixture was washed three times with distilled water. The organic layer was dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. The obtained crude product was recrystallized in an acetonitrile / ethanol (2:1) solution, filtered, and the filtered crystals were washed with ethanol to obtain crude crystals of compound 8. The crude crystals were purified by column chromatography (SiO2, CHCl3) to obtain crystals of compound 8 (yield 7.1 g, yield 49%).

[0098] (Synthesis of DA-v-7) A mixture of compound 8 (12.2 g, 22.4 mmol), 5% palladium carbon (wet product, 1.22 g, 10 wt%), and dioxane (120 g) was stirred in the presence of hydrogen at 60°C for 4 hours. After the reaction was completed, the mixture was purged with nitrogen and filtered through Celite at 60°C. The filtrate was distilled under reduced pressure to remove the solvent, yielding a crude product. The crude product was recrystallized from 2-propanol / ethyl acetate (2:1) to obtain the target product, DA-v-7 (yield 8.0 g, 74%). 1 H-NMR(500MHz,CDCl3):δ(ppm)=7.725(1H,d),7.577(2H,m),7.272(2H,m),7.102(1H,s),6.79 1(1H,d),6.207(1H,d),6.117(1H,dd),3.621(4H,broad),2.553(1H,m),2.067-0.863(31H,m).

[0099] <Synthesis of diamine [DA-n-10]> Compound [DA-n-10] was synthesized according to the following scheme.

[0100] [ka]

[0101] (Synthesis of compound [1]) tert-Butyl (5-hydroxy-1-naphthalenyl) carbamate (27.0 g, 104 mmol) was charged with N,N-dimethylformamide (216 g) and potassium carbonate (33 g, 239 mmol) and stirred at 80 ° C. Next, a solution of 1,2-bis (4-methylbenzenesulfonate)-1,2-ethanediol (18.0 g, 496 mmol) in N,N-dimethylformamide (162 g) was added dropwise using a dropping funnel, and the mixture was heated and stirred at 80 ° C. overnight. After the reaction was completed, the reaction solution was poured into water (2268 g) to precipitate crystals. The mixture was filtered using a Buchner funnel to obtain sticky black purple crystals (93 g). The crude product was dissolved in N,N-dimethylformamide by heating at 80°C, cooled to room temperature, and crystallized in methanol. The product was filtered and dried to obtain compound [1] (yield: 28.0 g, 51.4 mmol, 67% yield). 1 H-NMR(500MHz,DMSO-d6):δ(ppm)=9.14(s,2H),7.98(d,J=10.0Hz,2H),7.64(d,J=10.0Hz,2H),7.55(d,J=1 0.0Hz,2H),7.46(t,J=7.5Hz,2H),7.39(t,J=7.5Hz,2H),7.13(d,J=10.0Hz,2H),4.65(s,4H),1.49(s,18H).

[0102] (Synthesis of compound [DA-n-10]) Compound [1] (28.0 g, 51.4 mmol) was charged with chloroform (374 g) and potassium carbonate (33 g, 239 mmol) and stirred at 80 ° C. Next, trifluoroacetic acid (31.0 g, 313 mmol) was slowly dropped using a dropping funnel, and the mixture was heated and stirred at 50 ° C. for 6 hours, and gray crystals were precipitated in the reaction system. After cooling to 25 ° C., the reaction liquid was poured into water (374 g) and filtered. Triethylamine and water were added to the obtained crystals and stirred to liberate the diamine from the trifluoroacetate salt, and the mixture was filtered again, washed with methanol and then hexane, and dried to obtain compound [DA-n-10] (yield: 9.30 g, 27.0 mmol, 86% yield). 1H-NMR(500MHz,DMSO-d6):δ(ppm)=7.65(d,J=7.5Hz,2H),7.41(d,J=8.0Hz,2H),7.29(t,J=8.0Hz, 2H),7.12(t,J=8.0Hz,2H),7.00(t,J=7.5Hz,2H),6.67(d,J=7.5Hz,2H),5.62(s,4H),4.56(s,4H).

[0103] [Synthesis of polyamic acid] <Synthesis Example 1> In a 100mL four-necked flask equipped with a stirrer, 1.66g (7.00mmol) of DA-4, 2.89g (8.75mmol) of DA-5, 5.30g (7.00mmol) of DA-v-6, and 2.43g (12.3mmol) of DA-13 were weighed out, 49.1g of NMP was added, and the mixture was stirred to dissolve. While stirring this diamine solution, 7.53g (33.6mmol) of DC-3 was added, and 30.1g of NMP was further added. The mixture was stirred at 60℃ for 15 hours to obtain a solution of polyamic acid (Aa-1, viscosity: 649mPa·s, Mn: 14,231).

[0104] <Synthesis Examples 2 to 7> Except for changing the diamine component and the acid dianhydride component to those shown in Table 1 below, the same procedure as in Synthesis Example 1 was carried out to obtain polymer (polyamic acid) solutions (Aa-2), (Aa-3), (Ab-4), (Ab-5), (Ar-6), and (Ar-7) shown in Table 1 below. The viscosity and molecular weight of the polyamic acids obtained in Synthesis Examples 1 to 7 are shown in Table 1 below.

[0105] [Table 1]

[0106] [Preparation of liquid crystal alignment agent] <Comparative Example 1> NMP (6.0 g) and BCS (8.0 g) were added to the solution (6.0 g) of polyamic acid (Aa-1) obtained above, and the mixture was stirred at room temperature for 10 hours to prepare a liquid crystal alignment agent (R-1) containing 6 mass % of polyamic acid (Aa-1), 54 mass % of NMP, and 40 mass % of BCS.

[0107] <Comparative Examples 2 and 3> The liquid crystal alignment agents (R-2) and (R-3) shown in Table 2 below were obtained by carrying out the same procedure as in Comparative Example 1, except that the polyamic acid (Aa-1) was replaced with polyamic acids (Aa-2) and (Aa-3), respectively.

[0108] <Example 1> Instead of polyamic acid (Aa-1), the polyamic acid (Aa-1) and polyamic acid (Ab-4) prepared above were used to obtain a liquid crystal alignment agent (1) shown in Table 2 below, in which the component ratio (mass ratio calculated as solid content) of polyamic acid (Aa-1) to polyamic acid (Ab-4) was (Aa-1) / (Ab-4)=30 / 70, and the component mass ratio of the solid content of the polymer component to the solvent was (solid content) / NMP / BCS=6 / 54 / 40.

[0109] <Examples 2 to 4 and Comparative Examples 4 to 9> Except for changing the polyamic acid solution to that shown in Table 2 below, the same procedure as in Example 1 was carried out to obtain liquid crystal alignment agents (2) to (4) of Examples 2 to 4 and liquid crystal alignment agents (R-4) to (R-9) of Comparative Examples 4 to 9, respectively, as shown in Table 2 below. In Table 2, the numbers in parentheses in the polymer composition indicate the blending ratio (parts by mass) of each polymer component relative to 100 parts by mass of the total of the polymer components used in the preparation of the liquid crystal alignment agent. The solid content ratio and solvent composition ratio indicate the blending ratio (parts by mass) of the polymer solid content and each organic solvent relative to 100 parts by mass of the total of the polymer solid content and each organic solvent used in the preparation of the liquid crystal alignment agent.

[0110] [Table 2]

[0111] [Preparation of liquid crystal alignment film] Using the liquid crystal alignment agents prepared in the above respective Examples, liquid crystal alignment films were produced as follows. The liquid crystal alignment agent prepared in each of the above examples was spin-coated onto a quartz substrate or a silicon wafer, dried on a hot plate at 70°C for 90 seconds, and then baked in a hot air circulation oven (MB1-1G3030X, manufactured by Denko Corporation) at 230°C for 20 minutes to form a liquid crystal alignment film with a thickness of 100 nm.

[0112] [Measurement of refractive index of liquid crystal alignment film] The refractive index was measured at 250 to 800 nm using a spectroscopic ellipsometer (JA Woollam, Inc.) (M-2000) and fitting with the CAUCHY model. The results are shown in Table 3. Table 3 also shows the refractive index at 550 nm. A refractive index of more than 1.62 was rated as "good," and a refractive index of 1.62 or less was rated as "poor."

[0113] [Measurement of transmittance of liquid crystal alignment film] The transmittance was measured at 380 to 800 nm using an ultraviolet-visible spectrophotometer (Shimadzu Corporation) (UV-2600). The results are shown in Table 3. Table 3 shows the average transmittance at 380 to 800 nm. A measurement cell was made using two quartz substrates. A liquid crystal alignment film was formed on one of the two substrates, and a quartz substrate without a liquid crystal alignment film was attached to it with the side on which the liquid crystal alignment film was formed facing inward. A refractive index liquid (contact liquid, manufactured by Shimadzu Device Mfg. Co., Ltd.) was inserted between the two substrates using a dropper to make a measurement cell. A refractive index liquid was used according to each of the 11 types of refractive index liquids ranging from 1.60 to 1.70 in 0.01 increments. A transmittance of more than 99.0% was rated as "good", and a transmittance of 99.0% or less was rated as "poor".

[0114] [Table 3]

[0115] The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2019-173298, filed on September 24, 2019, 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 components (A) and (B): Component (A): At least one polymer (A) selected from the group consisting of a polyimide precursor obtained by using a diamine component containing diamine (a) represented by the following formula [1] or formula [2] having at least one structure selected from the group consisting of structures represented by the following formulas (S1) to (S3), and a polyimide which is an imidized product of the polyimide precursor. Component (B): At least one polymer (B) selected from the group consisting of a polyimide precursor obtained by using a diamine component containing a diamine (b) represented by the following formula (2) and a polyimide which is an imidized product of the polyimide precursor: 【Chemistry 1】 (X １ -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -O-, -OCO- or -((CH ２ ) ａ１ -A １ ) ｍ１ - (a1 is an integer from 1 to 15, A １ represents an oxygen atom or -COO-; m １ is an integer from 1 to 2. １ When is 2, a plurality of a1 and A １ Each of X independently has the same definition as above. ２ is 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 １ ) ｍ１ - (a1 is an integer from 1 to 15, A １ represents an oxygen atom or -COO-; m １ is an integer from 1 to 2. １ When is 2, a plurality of a1 and A １ Each of the groups independently has the same definition as above. 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 with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. m and n each independently represent an integer of 0 to 3, and m+n is 2 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 the formula (I) may be substituted with a fluorine atom. 【Chemistry 2】 (X ３ -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -CH ２ Represents O- or -OCO-. ２ represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms; R ２ Any hydrogen atom forming the formula (I) may be substituted with a fluorine atom. 【Chemistry 3】 (X ４ is -CONH-, -NHCO-, -O-, -CH ２ O-, -OCH ２ represents - or -OCO-. ３ represents a structure having a steroid skeleton.) 【Chemistry 4】 (A １ and A ２ each independently represents a divalent monocyclic or condensed ring group which may have a substituent; A １ and A ２ At least one of the groups represents a divalent fused ring group which may have a substituent, and the fused ring group is a divalent group obtained by removing two hydrogen atoms from a fused ring which is any one of naphthalene, anthracene, pyrene, carbazole, coumarin, benzo-pyrone, quinoline, and isoquinoline. L represents a single bond, -COO-, -CO-S-, -CO-, -CONR- (wherein R represents a hydrogen atom or a monovalent alkyl group having 1 to 6 carbon atoms), -O-, -S-, or a divalent organic group. m and n each independently represent an integer of 1 to 3. 【Chemistry 5】 (X is a single bond, -O-, -C(CH ３ ) ２ -, -NH-, -CO-, -(CH ２ ) ｍ -, -SO ２ -, -O-(CH ２ ) ｍ -O-, -OC(CH ３ ) ｍ --, --CO-(CH ２ ) ｍ -, -NH-(CH ２ ) ｍ -, -SO ２ - (CH ２ ) ｍ -, -CONH-(CH ２ ) ｍ -, -CONH-(CH ２ ) ｍ -NHCO-, -COO-(CH ２ ) ｍ -OCO-, -COO-, -CONH-, -NH-(CH ２ ) ｍ -NH- or -SO ２ - (CH ２ ) ｍ -SO ２ -. m is an integer of 1 to 8. Y represents any of the structures of the formulas (S1) to (S3), and the two Y's in the formula [2] may be the same or different.

2. The diamine represented by the formula [1] is the following formulas [S-1] to [S-6], [S-11], [S-13], [S-14], [S-16], and [S-17]. The liquid crystal aligning agent according to claim 1. 【Chemistry 6】 (n is an integer from 1 to 20.) 【Chemistry 7】

3. The liquid crystal aligning agent according to claim 1, wherein the diamine represented by the formula [2] is one of the following formulas [W-1] to [W-6]. 【Chemistry 8】 (X ｐ１ ~X ｐ８ Each independently represents -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -O-, -CH ２ O-, -CH ２ It is OCO- or -OCO-. ｓ１ ~X ｓ４ are each independently -O-, -CH ２ O-, -OCH ２ represents - or -OCO-. ａ ~X ｆ is -O-, -NH-, -O-(CH ２ ) ｍ -O-, -C(CH ３ ) ２ -, -CO-, -COO-, -CONH-, -(CH ２ ) ｍ -, -SO ２ -, -O-C(CH ３ ) ２ --, --CO-(CH ２ ) ｍ -, -NH-(CH ２ ) ｍ -, -NH-(CH ２ ) ｍ -NH-, -SO ２ - (CH ２ ) ｍ -, -SO ２ - (CH ２ ) ｍ -SO ２ -, -CONH-(CH ２ ) ｍ -, -CONH-(CH ２ ) ｍ -NHCO- or -COO-(CH ２ ) ｍ represents —OCO—. １ａ ~R １ｈ each independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms; and m is an integer of 1 to 8.

4. A in the formula (2) １ , A ２ The liquid crystal aligning agent according to any one of claims 1 to 3, wherein the monocyclic group in the formula (I) is a divalent group in which two hydrogen atoms have been removed from a monocyclic ring which is either benzene or pyridine.

5. In the formula (2), L is a single bond, -(CH ２ ) ｎ -(n is an integer from 1 to 20), -O-(CH ２ ) ｎ -O- (n is an integer from 1 to 20), -O-(CH ２ ) ｎ -(n is an integer from 1 to 20), -S-(CH ２ ) ｎ -S- (n is an integer from 1 to 20), or -S-(CH ２ ) ｎ The liquid crystal aligning agent according to any one of claims 1 to 4, wherein n is an integer of 1 to 20.

6. The liquid crystal aligning agent according to any one of claims 1 to 5, wherein m and n in the formula (2) are 1 or 2.

7. The liquid crystal aligning agent according to any one of claims 1 to 6, wherein at least one of the polyimide precursors of the polymer (A) and the polymer (B) is obtained by a polymerization reaction of a diamine component containing the diamine (a) or a diamine component containing the diamine (b) and a tetracarboxylic acid component containing a tetracarboxylic acid dianhydride represented by the following formula (3) or a derivative thereof: 【Chemistry 9】 (X represents a structure selected from the group consisting of the following (x-1) to (x-13).) 【Chemistry 10】 (R １ ~R ４ R each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom, or a phenyl group. ５ and R ６ Each of j and k independently represents an integer of 0 or 1; １ and A ２ each independently represents a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or an amide group; ２ may be the same or different. *1 is a bond bonded to one acid anhydride group, and *2 is a bond bonded to the other acid anhydride group.)

8. The liquid crystal aligning agent according to claim 7, wherein X in the formula (3) is a structure selected from the group consisting of the formulas (x-1) to (x-7) and (x-11) to (x-13).

9. The liquid crystal aligning agent according to any one of claims 1 to 8, wherein the mass ratio ((A) / (B)) of the content of the (A) component to the content of the (B) component is 5 / 95 to 80 / 20.

10. A liquid crystal alignment film formed by using the liquid crystal aligning agent according to any one of claims 1 to 9.

11. A liquid crystal display device comprising the liquid crystal alignment film according to claim 10.

12. A method for manufacturing a liquid crystal display element, comprising: applying the liquid crystal alignment agent according to any one of claims 1 to 9 onto a pair of substrates having conductive films to form coating films; arranging the coating films so as to face each other via a layer of liquid crystal molecules to form a liquid crystal cell; and irradiating the liquid crystal cell with light while applying a voltage between the conductive films of the pair of substrates.

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