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

Abstract

The present invention provides a liquid crystal alignment agent that forms a liquid crystal alignment film having a high refractive index and a high light transmittance due to non-colorability, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film. A liquid crystal alignment agent, characterized in that it contains the following (A) components and (B) components. (A) component: at least one polymer (A) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (a), and a polyimide that is an imide product of the polyimide precursor, wherein the diamine (a) has at least one selected from the group consisting of structures represented by the following formulas (S1) to (S3). (B) component: at least one polymer (B) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (b) represented by the following formula (2), and a polyimide that is an imide product of the polyimide precursor. (X 1 , X 2 Represents a single bond, ‑(CH2) a ‑(a is an integer from 1 to 15), etc. 1 and G 2 represents a divalent aromatic group having 6 to 12 carbon atoms, etc. m and n are 0 to 3. 1 represents an alkyl group having 1 to 20 carbon atoms. )(X 3 Represents a single bond, ‑CONH‑, etc. R 2 represents an alkyl group having 1 to 20 carbon atoms. )(X 4 Indicates ‑CONH‑, ‑NHCO‑, etc. R 3 It represents a structure having a steroid skeleton. )(A1 and A2 represent a divalent monocyclic group or a condensed ring group, and at least one of A1 and A2 represents a divalent condensed ring group. L represents a single bond or a divalent organic group. m and n are 1 to 3.)#imgabs0# ‑X 3 ‑R 2 (S2) ‑X 4 ‑R 3 (S3)#imgabs1#

Description

Technical Field

[0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal aligning film obtained from the liquid crystal aligning agent, and a liquid crystal display element including the liquid crystal aligning film. Background Art

[0002] Conventionally, various driving methods have been developed as liquid crystal display elements, with different electrode structures, physical properties of the liquid crystal molecules used, etc. For example, 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.

[0003] Liquid crystal display elements are usually configured as follows: a pair of electrode substrates are arranged in a manner that they are opposed to each other with a predetermined gap (several μm), and liquid crystal is sealed between the electrode substrates. In addition, the display in the liquid crystal display element is performed by applying a voltage between the transparent conductive films of the electrodes constituting the electrode substrates. In addition, these liquid crystal display elements have a liquid crystal alignment film for orienting the liquid crystal molecules. As materials for the liquid crystal alignment film, for example, polyamic acid, polyamic acid ester, polyimide, polyamide, etc. are known (see Patent Document 1, etc.).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2016 / 080458 Summary of the invention

[0007] Problems to be solved by the invention

[0008] Furthermore, the above-mentioned transparent conductive film in the liquid crystal display element is usually formed by a composition (ITO) in which indium oxide is mainly composed and several percent of tin oxide is doped therein, but its refractive index is different from that of the liquid crystal alignment film and has a high value. Therefore, when trying to make the light from the display light source pass through the electrode substrate, the light will be reflected at the boundary surface between the transparent conductive film and the liquid crystal alignment film in each electrode substrate. As a result, the transmittance of the electrode substrate cannot be fully obtained, resulting in the undesirable situation of reduced display brightness.

[0009] In particular, in recent years, ultra-high-definition panels such as 4K and 8K are being developed, but in these panels, the occupancy rate of the black matrix (BM), TFT, etc. increases, the aperture ratio of the panel decreases, and attention is paid to improving the transmittance of the display part.

[0010] Therefore, the inventors of the present invention have conducted various studies on the materials for forming the liquid crystal alignment film in order to improve the refractive index of the liquid crystal alignment film, considering that the above-mentioned undesirable situation can be eliminated by reducing the difference between the refractive index of the transparent conductive film and the refractive index of the liquid crystal alignment film. Specifically, the inventors have explored the types of polymers contained in the liquid crystal alignment agents for forming the liquid crystal alignment film in order to improve the refractive index of the liquid crystal alignment film.

[0011] As a result, it was found that a liquid crystal alignment film having a high refractive index close to that of a transparent conductive film can be obtained by selecting a specific polymer, but on the other hand, when there are many polymers forming a liquid crystal alignment film having a high refractive index, the liquid crystal alignment film has coloration. Due to this, the light transmittance of the liquid crystal alignment film formed by the liquid crystal alignment agent containing the coloration polymer is reduced, resulting in a reduction in display brightness, and as a result, the above-mentioned purpose cannot be achieved.

[0012] In view of the above situation, an object of the present invention is to provide a liquid crystal alignment agent for forming a liquid crystal alignment film having a high refractive index and a high light transmittance due to lack of coloration, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film.

[0013] Solutions for solving problems

[0014] The present inventors have conducted intensive studies to achieve the above problems and have found that a liquid crystal aligning agent containing a part of a novel polymer and two or more polymers having a specific structure is effective for achieving the above purpose, thereby completing the present invention.

[0015] The present invention provides a liquid crystal aligning agent, a liquid crystal aligning film obtained from the liquid crystal aligning agent, and a liquid crystal display element having the liquid crystal aligning film. The liquid crystal aligning agent is characterized by containing the following (A) component and (B) component.

[0016] Component (A): at least one polymer (A) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (a) having at least one selected from the group consisting of structures represented by the following formulae (S1) to (S3), and a polyimide which is an imidate of the polyimide precursor.

[0017] (B) Component: at least one polymer (B) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (b) represented by the following formula (2) and a polyimide which is an imidation product of the polyimide precursor.

[0018]

[0019] (X1 and X 2 Each independently represents 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, a plurality of a1s and A1s each independently have the above definition). 1 and G 2 Each 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 is optionally substituted by an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. m and n are each independently 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, forming R 1 Any hydrogen atom of is optionally substituted by a fluorine atom. )

[0020] -X 3 -R 2 (S2)

[0021] (X 3 R represents a single bond, -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2O-, -COO- or -OCO-. 2 represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, forming R 2 Any hydrogen atom of the compound may be substituted by a fluorine atom.

[0022] -X 4 -R 3 (S3)

[0023] (X 4 Represents -CONH-, -NHCO-, -O-, -CH2O-, -OCH2-, -COO- or -OCO-. 3 Indicates a structure with a steroidal skeleton.)

[0024]

[0025] (A1 and A2 each independently represent a divalent monocyclic group or condensed ring group optionally having a substituent, and at least one of A1 and A2 represents a divalent condensed ring group optionally having a substituent. L represents a single bond, -COO-, -CO-S-, -CO-, -CONR- (wherein R is 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.)

[0026] Effects of the Invention

[0027] According to the present invention, a liquid crystal alignment agent can be obtained that forms a liquid crystal alignment film having a high refractive index and having a high light transmittance due to lack of coloring. The liquid crystal alignment film formed by the liquid crystal alignment agent can reduce the difference between the refractive index of the transparent conductive film in the liquid crystal display element and the refractive index of the liquid crystal alignment film, and further, because it has no coloring, it is possible to obtain a liquid crystal display element having a high light transmittance and a high display brightness. DETAILED DESCRIPTION

[0028] The liquid crystal aligning agent of this invention contains the following (A) component and (B) component, as mentioned above, It is characterized by the above-mentioned.

[0029] (Component A: polymer (A))

[0030] The component (A) in the present invention is at least one polymer (A) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (a) having at least one selected from the group consisting of structures represented by the following formulae (S1) to (S3), and a polyimide which is an imide product of the polyimide precursor.

[0031]

[0032] X in formula (S1) 1 , X 2 , G 1 , G 2 , R 1 The definitions of , m, and n are as described above.

[0033] It should be noted that as G 1 , G 2 The divalent cyclic group in the formula (a) includes, for example, cyclopropylene, cyclohexylene, and phenylene. 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 fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms, or a fluorine atom.

[0034] -X 3 -R 2 (S2)

[0035] In formula (S2), X 3 , R 2 The definition of is as described above. It should be noted that, from the perspective of improving the liquid crystal orientation, R 2 An alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms is preferred.

[0036] -X 4 -R 3 (S3)

[0037] In formula (S3), X 4 , R 3 The definition of is as above. In addition, R 3 A structure containing a cholesteryl group, a cholesterol group or a lanostanyl group is preferred.

[0038] Preferred embodiments of the formula (S1) include the following formulas [S1-x1] to [S1-x7].

[0039]

[0040] 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 For -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-. A1 is an oxygen atom or -COO-* (wherein the bond with "*" is the bond with (CH2) a2 bonding), A2 is an oxygen atom or *-COO- (wherein, the bonding with "*" is bonded to (CH2) a2 bond), a3 is 0 or 1, a1 and a2 are each independently an integer of 1 to 10, Cy is 1,4-cyclohexylene or 1,4-phenylene

[0041] As a preferred embodiment of formula (S2), X 3 is any of -O-, -CH2O-, -COO- or -OCO-, preferably R 2 In the case of an alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, R 2 In the case of an alkyl group having 3 to 20 carbon atoms, R 2 Any hydrogen atom of is optionally substituted by a fluorine atom.

[0042] As a preferred embodiment of the above formula (S3), the following formula [S3-x] can be cited. It should be noted that 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.

[0043]

[0044] As the diamine (a) having the structure represented by the above formulae (S1) to (S3), preferably, there is mentioned a diamine represented by the following formula [1] or [2].

[0045]

[0046] In the above formulas [1] and [2], Y represents a side chain structure represented by the above formulas (S1) to (S3), and the two Ys in formula [2] are optionally the same or different. In addition, X represents 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-, -COO-(CH2) m -OCO-, -COO-, -CONH-, -NH-(CH2) m -NH- or -SO2-(CH2) m -SO2-. m is an integer from 1 to 8.

[0047] Preferred examples of the diamine represented by the above formula [1] include the following formulas [S-1] to [S-18].

[0048]

[0049] (n is an integer from 1 to 20.)

[0050]

[0051] Preferred examples of the diamine represented by the above formula [2] include structures selected from the group consisting of the following formulae [W-1] to [W-6].

[0052]

[0053] In the above formula, X p1 ~X p8 Each independently of X in the formula [S1-x1] to [S1-x6] p Synonymous. s1 ~X s4 Each independently represents -O-, -CH2O-, -OCH2-, -COO- or -OCO-. a ~X f Indicates -O-, -NH-, -O-(CH2) m -O-, -C(CH3)2-, -CO-, -COO-, -CONH-, -(CH2) m -, -SO2-, -O-C(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-,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.

[0054] (Component B: polymer (B))

[0055] The component (B) in the present invention is at least one polymer (B) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a part of the novel diamine (b) represented by the following formula (2) and a polyimide which is an imidation product of the polyimide precursor.

[0056]

[0057] In the above formula (2), A1, A2, L, m and n are as defined above.

[0058] The monocyclic group in A1 and A2 refers to a divalent group formed by removing two hydrogen atoms from a monocyclic ring. Examples of the monocyclic ring include benzene; five-membered heterocyclic rings such as furan, thiophene, pyrrole, oxazole, thiazole, imidazole, and pyrazole; and six-membered heterocyclic rings such as pyran, pyrone, pyridine, pyridazine, pyrimidine, and pyrazine. The monocyclic ring is preferably benzene or pyridine. It should be noted that when the monocyclic ring is benzene, the monocyclic group is phenylene.

[0059] The condensed ring group in A1 and A2 refers to a divalent group formed by removing two hydrogen atoms from a condensed ring. As the condensed ring, for example, there can be listed: condensed polycyclic aromatic hydrocarbons such as naphthalene, tetralin, indene, fluorene, anthracene, phenanthrene, and pyrene; condensed polycyclic heterocyclic rings such as benzofuran, benzothiophene, indole, carbazole, coumarin, benzopyrone, quinoline, isoquinoline, acridine, phthalazine, quinazoline, and quinoxaline. The condensed ring is preferably any of naphthalene, anthracene, pyrene, indole, carbazole, coumarin, benzopyrone, quinoline, or isoquinoline.

[0060] The monocyclic group and condensed ring group in A1 and A2 may have a substituent. Examples of the substituent in the monocyclic group and condensed ring group include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom.

[0061] Examples of the divalent organic group in L include: a divalent chain hydrocarbon group having 1 to 20 carbon atoms; a group in which at least one methylene group of the chain hydrocarbon group is substituted by -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 straight, and may be saturated or unsaturated. Examples of the divalent chain hydrocarbon group having 1 to 20 carbon atoms include alkylene groups 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 1 to 20, more preferably 1 to 10, and further preferably an integer of 1 to 6), -O-(CH2) n -O- (n is 1 to 20, more preferably 1 to 10, and further preferably an integer of 1 to 6), -O-(CH2) n -(n is 1 to 20, more preferably 1 to 10, and even more preferably an integer of 1 to 6), -S-(CH2) n -S- (n is 1 to 20, more preferably 1 to 10, and even more preferably an integer of 1 to 6), or -S-(CH2) n - (n is 1 to 20, more preferably 1 to 10, and even more preferably an integer of 1 to 6). m and n related to A1 and A2 in the above formula (2) are preferably 1 or 2.

[0062] Among them, the diamine (b) is preferably a diamine represented by the following formula (2-1) to (2-25).

[0063]

[0064]

[0065] (Production of polymer (A) and polymer (B))

[0066] The polymer (A) and polymer (B) contained in the liquid crystal aligning agent of the present invention are polyimide precursors (A) and (B) obtained using a diamine component containing the diamine (a) and a diamine component containing the diamine (b), or polyimides (A) and (B) as imides of the polyimide precursors. Here, the polyimide precursor is a polymer that can obtain a polyimide by imidization of polyamic acid, polyamic acid ester, etc.

[0067] The polyamic acid (A) which is a polyimide precursor of the above-mentioned polymer (A) can be obtained by a polymerization reaction of a diamine component containing the above-mentioned diamine (a) and a tetracarboxylic acid component.

[0068] In this case, the amount of diamine (a) used is preferably 1 mol% or more, more preferably 5 mol% or more relative to the diamine component 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.

[0069] The polyamic acid (B) which is a polyimide precursor of the above-mentioned polymer (B) can be obtained by a polymerization reaction of a diamine component containing the above-mentioned diamine (b) and a tetracarboxylic acid component.

[0070] In this case, the amount of diamine (b) used is preferably 1 mol% or more, more preferably 2 mol% or more relative to 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.

[0071] The diamine component used in the production of the polyamic acids (A) and (B) may include diamines other than diamine (a) and diamines other than diamine (b) (hereinafter also referred to as other diamines). Examples of other diamines are given below, but the present invention is not limited thereto.

[0072] p-phenylenediamine, m-phenylenediamine, 4-(2-(methylamino)ethyl)aniline, diamines having a carboxyl group such as 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 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, bis(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 benzene, 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-aminophenyl)propane, a diamine having a urea bond such as 1,3-bis(4-aminophenethyl)urea, a diamine represented by the following formulas (a-1) to (a-6), preferably a diamine having a photopolymerizable group at the terminal such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline, a diamine having a photopolymerizable group at the terminal such as the following formula (R1 ) to (R5) and the like having a radical initiating function, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, diamines having a heterocyclic ring such as the following formula (z-1) to (z-18), diamines having a diphenylamine skeleton such as the following formula (Dp-1) to (Dp-3), diamines having an oxazoline structure such as the following formula (Ox-1) to (Ox-2), diamines containing an organosiloxane such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and diamines described in International Publication No. 2016 / 125870.

[0073]

[0074]

[0075] (d1 represents an integer from 2 to 10.)

[0076]

[0077] (n represents an integer from 2 to 10.)

[0078]

[0079] From the perspective of improving the response speed of liquid crystal display elements using the PSA (Polymer Sustained Alignment) method and the SC-PVA (Patterned Vertical Alignment) mode, the 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, the diamine having a photopolymerizable group at the end, the diamine represented by the above formulas (R1) to (R5), and the diamine represented by the above formulas (z-1) to (z-18) can be used alone or in combination when producing polyamic acids (A) and (B).

[0080] As other diamines, among the above, from the viewpoint of preferably obtaining the effect 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 formulae (R1) to (R5), diamines represented by the above formulae (z-1) to (z-18), diamines represented by the above formulae (Dp-1) to (Dp-3), and diamines represented by the above formulae (Ox-1) to (Ox-2) are preferred.

[0081] When producing polyamic acid (A), the amount of the other diamines is preferably 1 to 99 mol%, more preferably 1 to 95 mol%, and further preferably 5 to 95 mol% relative to the total diamine components used. When producing polyamic acid (B), the amount of the other diamines is preferably 1 to 99 mol%, more preferably 2 to 99 mol%, and further preferably 2 to 98 mol% relative to the total diamine components used.

[0082] Moreover, when manufacturing polyamic acid (A) and (B), from the viewpoint of improving the solvent solubility of the polymer in a liquid crystal aligning agent and improving the voltage holding ratio of the obtained liquid crystal aligning film, at least one diamine represented by the following formula (5) can be used.

[0083] H2N-Y1-NH2 (5)

[0084] Here, Y1 represents a divalent organic group having a structure represented by the following formula (6).

[0085]

[0086] In formula (6), D represents a protecting group that is detached by heating and replaced by a hydrogen atom, and * represents a linking site to another structure. Preferred structures of D include tert-butoxycarbonyl.

[0087] Preferred specific examples of the diamine represented by formula (5) are listed below. In addition, Boc in the following description represents a tert-butoxycarbonyl group.

[0088]

[0089] When the diamine represented by formula (5) is used, the amount of the diamine represented by formula (5) is preferably 1 to 50 mol%, more preferably 5 to 40 mol%, based on the total diamine components used when producing either polyamic acid (A) or (B).

[0090] (Tetracarboxylic acid component)

[0091] When producing the polyamic acids (A) and (B), the tetracarboxylic acid component to be reacted with the diamines (a) and (b) is not limited to tetracarboxylic dianhydride but may be a derivative of tetracarboxylic dianhydride such as tetracarboxylic acid, tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl ester dihalide.

[0092] The above-mentioned tetracarboxylic dianhydride or its derivatives can be listed as: aromatic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, or their derivatives. Here, aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group with an aromatic ring. Aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. Among them, it is not necessary to be composed only of a chain hydrocarbon structure, and alicyclic structure and aromatic ring structure may be present in a part thereof. Alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an alicyclic structure. Among them, none of these four carboxyl groups are bonded to an aromatic ring. In addition, it is not necessary to be composed only of an alicyclic structure, and a chain hydrocarbon structure and aromatic ring structure may be present in a part thereof. With regard to the above-mentioned tetracarboxylic dianhydride or its derivatives, the tetracarboxylic dianhydride or its derivatives shown in the following formula (3) is preferred.

[0093]

[0094] However, in formula (3), X represents a structure selected from the group consisting of the following (x-1) to (x-13).

[0095]

[0096] In the above formula (x-1), R1 ~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 independently represents a hydrogen atom or a methyl group. j and k are each independently 0 or 1, A1 and A2 are each independently a single bond, ether (-O-), carbonyl (-CO-), ester (-COO-), phenylene, sulfonyl (-SO2-) or amide (-CONH-), and two A2s are optionally the same or different. *1 is a bond to the anhydride group of one side, and *2 is a bond to the anhydride group of the other side.

[0097] Preferred specific examples of the above formulae (x-12) and (x-13) include the following formulae (x-14) to (x-29). * represents a bonding bond.

[0098]

[0099] Preferred examples of the tetracarboxylic dianhydride or its derivative represented by the above formula (3) include tetracarboxylic dianhydride or its derivative represented by the formula (3) wherein X is the above formula (x-1) to (x-7) and (x-11) to (x-13).

[0100] The proportion of tetracarboxylic dianhydride or its derivative represented by the formula (3) is preferably 1 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, based on 1 mol of the tetracarboxylic acid component used, in either polyamic acid (A) or (B).

[0101] The tetracarboxylic acid component used for producing the polyamic acids (A) and (B) may contain tetracarboxylic dianhydride or a derivative thereof other than the above formula (3).

[0102] The production of polyamic acid (A) and (B) is carried out by reacting a diamine component containing diamine (a) or diamine (b) with a tetracarboxylic acid component in a solvent (polycondensation). The solvent is not particularly limited as long as it dissolves the generated polymer.

[0103] Specific examples of the above-mentioned solvent include: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone. In addition, when the polymer has high solvent solubility, 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.

[0104]

[0105] (In formula [D-1], D 1 represents an alkyl group having 1 to 3 carbon atoms, wherein D 2 represents an alkyl group having 1 to 3 carbon atoms, wherein D 3 represents an alkyl group having 1 to 4 carbon atoms).

[0106] These solvents may be used alone or in combination. Furthermore, even if the solvent does not dissolve the polymer, it may be used in combination with the above-mentioned solvents within a range in which the generated polymer does not precipitate.

[0107] When the diamine component and the tetracarboxylic acid component are reacted in a solvent, the reaction can be carried out at any concentration, and the concentration of the diamine component and the tetracarboxylic acid component relative to 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 initial stage, and then the solvent can be added.

[0108] In the reaction, the total molar ratio of the diamine components to the tetracarboxylic acid components (total molar ratio of diamine components / total molar ratio of tetracarboxylic acid components) is preferably 0.8 to 1.2. As in a normal polycondensation reaction, the closer this molar ratio is to 1.0, the greater the molecular weight of the generated specific polymer.

[0109] The polyamic acid ester as a polyimide precursor can be obtained by, for example, a known method such as [I] a method of reacting a 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.

[0110] [Polyimide]

[0111] The polyimide contained in the liquid crystal aligning agent of the present invention is a polyimide (A) or (B) obtained by ring-closing the polyimide precursor. In the polyimide, the ring-closure ratio (also referred to as imidization ratio) of the amic acid group is not necessarily required to be 100% and can be adjusted arbitrarily.

[0112] As a method for imidizing a polyimide precursor to obtain polyimides (A) and (B), there can be mentioned: thermal imidization in which a solution of a polyimide precursor is directly heated, or catalytic imidization in which a catalyst is added to a solution of a polyimide precursor. The temperature when the polyimide precursor is thermally imidized in a solution is 100 to 400° C., preferably 120 to 250° C., and it is preferably carried out while removing water generated by the imidization reaction to the outside of the system.

[0113] The catalytic imidization of the polyimide precursor is carried out as follows: a basic catalyst and an acid anhydride are added to a solution of the polyimide precursor, and stirred at -20 to 250°C, preferably at 0 to 180°C. The amount of the basic catalyst is 0.5 to 30 times the molar amount of the amic acid group, preferably 2 to 20 times the molar amount, and the amount of the acid anhydride is 1 to 50 times the molar amount of the amic acid group, preferably 3 to 30 times the molar amount. As a basic catalyst, pyridine, triethylamine, trimethylamine, tributylamine trioctylamine, etc. can be listed, among which pyridine has a moderate alkalinity for the reaction to proceed, so it is preferred. As an acid anhydride, acetic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. can be listed, among which, if acetic anhydride is used, purification after the reaction is completed becomes easy, so it is preferred. The imidization rate based on the catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[0114] In the case of recovering the generated polyimide from the imidization reaction solution of the polyimide precursor, the reaction solution is put into a solvent to precipitate it. As the solvent used for precipitation, there can be listed: methanol, ethanol, isopropanol, acetone, hexane, butyl cellulose, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, water, etc. After the polymer precipitated by the solvent is filtered and recovered, it can be dried at normal pressure or reduced pressure, at room temperature or by heating. In addition, when the polymer recovered by precipitation is redissolved in a solvent and the operation of reprecipitation recovery is repeated 2 to 10 times, the impurities in the polymer can be reduced. As the solvent at this time, for example, alcohols, ketone hydrocarbons, etc. can be listed. When three or more solvents selected from them are used, the efficiency of purification is further improved, so it is preferred.

[0115] The polyimide precursor and the polyimide preferably have a polystyrene-converted weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of 1,000 to 500,000, and more preferably 2,000 to 300,000. In addition, the molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the polystyrene-converted number average molecular weight (Mn) measured by GPC is preferably 15 or less, and more preferably 10 or less. Within this molecular weight range, good orientation of the liquid crystal display element can be ensured.

[0116] (Liquid Crystal Alignment Agent)

[0117] The liquid crystal aligning agent of the present invention is a liquid composition in which the polymer (A), the polymer (B), and other components used as needed are preferably dispersed or dissolved in an appropriate solvent.

[0118] With respect to the polymer (A) and the polymer (B) contained in the liquid crystal aligning agent of the present invention, the mass ratio of the content of the component (A) to the content of the component (B) ((A) / (B)) is preferably 5 / 95 to 80 / 20, and more preferably 10 / 90 to 60 / 40. In this way, a liquid crystal aligning film having a higher light transmittance can be provided while maintaining the surface characteristics such as the liquid crystal orientation required by the liquid crystal aligning film.

[0119] The liquid crystal aligning agent of the present invention may contain other polymers (hereinafter also referred to as other polymers) in addition to the polymers (A) and (B) for the purpose of improving electrical properties, solution properties, and the like.

[0120] The main skeleton of other polymers is not particularly limited, and examples thereof include: main skeletons such as polyimide precursors, polyimides, polysiloxanes, polyesters, polyamides, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-phenylmaleimide) derivatives, and poly(meth)acrylates. Among them, at least one selected from the group consisting of polyimide precursors, polyimides, polyamides, polyorganosiloxanes, poly(meth)acrylates, and polyesters is preferred, and at least one selected from the group consisting of polyimide precursors, polyimides, and polysiloxanes is more preferred. It should be noted that other polymers may also be used in combination of two or more.

[0121] The liquid crystal alignment agent of the present invention may also contain other components other than the above as required. As such components, for example, at least one compound selected from the group consisting of a cross-linking compound having the following substituents and a cross-linking compound having a polymerizable unsaturated group, a functional silane compound, a metal chelate compound, a curing accelerator, a surfactant, an antioxidant, a sensitizer, a preservative, a compound for adjusting the dielectric constant and resistance of the liquid crystal alignment film, etc., wherein the substituent is selected from at least one of an epoxy group, an isocyanate group, an oxetane group, a cyclocarbonate group, a blocked isocyanate group, a hydroxyl group and an alkoxy group. As specific examples of preferred cross-linking compounds, compounds shown in the following formulas (CL-1) to (CL-11) can be cited. As compounds for adjusting the dielectric constant and resistance of the liquid crystal alignment film, monoamines having nitrogen-containing aromatic heterocycles such as 3-aminomethylpyridine can be cited.

[0122]

[0123] 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, N-cyclohexyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropaneamide, 3-butoxy-N,N-dimethylpropaneamide, 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, ethylene glycol monoethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl 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, isopentyl propionate, isopentyl isobutyrate, diisoamyl ether, ethylene carbonate, propylene carbonate, etc. These may be used in combination of two or more.

[0124] The solid content concentration in the liquid crystal aligning agent (the ratio of the total mass of the components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc., and is preferably 1 to 10% by mass. From the perspective of forming a uniform and defect-free coating film, it is preferably 1% by mass or more, and from the perspective of the storage stability of the solution, it is preferably 10% by mass or less, and particularly preferably 2 to 8% by mass.

[0125] <Liquid crystal alignment film>

[0126] The liquid crystal alignment film for vertical alignment using the liquid crystal alignment agent of the present invention can be produced by applying the liquid crystal alignment agent on a substrate, sequentially performing drying and firing steps, and, if necessary, performing a brushing treatment, an alignment treatment by light irradiation, etc.

[0127] As the substrate used at this time, as long as it is a substrate with high transparency, there is no particular limitation. Except using a glass substrate, plastic substrates such as acrylic substrates and polycarbonate substrates can also be used. From the viewpoint of process simplification, it is preferred to use a substrate formed with an ITO electrode for liquid crystal drive, etc. In addition, in a reflective liquid crystal display element, if only a single-sided substrate, opaque substrates such as silicon wafers can also be used. As an electrode in this case, a material of reflected light such as aluminum can also be used.

[0128] Examples of the method for applying the liquid crystal alignment agent include screen printing, offset printing, flexographic printing, inkjet, dipping, roll coater, slit coating, spin coating, and spray coating. From the perspective of improving the production efficiency of the liquid crystal alignment film, a method of applying the liquid crystal alignment agent by flexographic printing or inkjet is preferred.

[0129] After the liquid crystal alignment agent is coated on the substrate, it is dried by a heating unit such as a heating plate, a thermal circulation oven, an IR (infrared) oven, etc., preferably at 40 to 150°C, depending on the solvent used in the liquid crystal alignment agent, and then preferably sintered at a temperature of 150 to 300°C, more preferably at 180 to 250°C, to form a liquid crystal alignment film.

[0130] If the thickness of the liquid crystal alignment film after baking is too thick, it is disadvantageous in the power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may decrease. Therefore, it is preferably 5 to 300 nm, more preferably 10 to 100 nm.

[0131] <Liquid crystal display device>

[0132] The liquid crystal display element of this invention comprises the said liquid crystal aligning film.

[0133] When the display mode of the manufactured liquid crystal display element is VA type, the coating film formed as described above can be used directly as a liquid crystal alignment film, or can be subjected to a brushing treatment or a PSA treatment described later as needed. On the other hand, when the display mode of the manufactured liquid crystal display element is a vertical electric field mode other than VA type and a horizontal electric field mode, the formed coating film surface is subjected to a brushing treatment or an alignment treatment by treatment such as polarized ultraviolet irradiation.

[0134] The liquid crystal alignment agent of the present invention is also preferably used for a liquid crystal display element manufactured by the following process: a liquid crystal layer is provided between a pair of substrates having electrodes, a liquid crystal composition containing a polymerizable compound polymerized by at least one of active energy rays and heat is arranged between the pair of substrates, a voltage is applied between the electrodes, and the polymerizable compound is polymerized by at least one of irradiation with active energy rays and heating. Here, the applied voltage can be set to, for example, a direct current or alternating current of 5 to 50 V. In addition, as active energy rays, ultraviolet rays are preferred. As ultraviolet rays, ultraviolet rays containing light with a wavelength of 300 to 400 nm are preferred, and ultraviolet rays containing light with a wavelength of 310 to 360 nm are preferred. As the irradiation amount of light, 0.1 to 20 J / cm 2 , more preferably 1 to 20 J / cm 2 .

[0135] As a method for manufacturing a liquid crystal display element using the liquid crystal alignment agent of the present invention, for example, the following method can be listed: the liquid crystal alignment agent is applied to a pair of substrates having a conductive film to form a coating film, the coating films are arranged opposite to each other with a layer of liquid crystal molecules therebetween to form a liquid crystal box, and the liquid crystal box is irradiated with light while a voltage is applied between the conductive films of the pair of substrates.

[0136] The above-mentioned liquid crystal display element controls the pre-tilt angle of the liquid crystal molecules through the PSA (Polymer Sustained Alignment) method. In the PSA method, a small amount of photopolymerizable compound, such as a photopolymerizable monomer, is mixed into the liquid crystal material in advance. After the liquid crystal box is assembled, the photopolymerizable compound is irradiated with ultraviolet rays or the like while a specified voltage is applied to the liquid crystal layer, and the pre-tilt angle of the liquid crystal molecules is controlled by the generated polymer. The alignment state of the liquid crystal molecules when the polymer is generated is also stored after the voltage is removed, so the pre-tilt angle of the liquid crystal molecules can be adjusted by controlling the electric field formed in the liquid crystal layer. In addition, in the PSA method, there is no need for brushing treatment, so it is suitable for the formation of a vertically oriented liquid crystal layer whose pre-tilt angle is difficult to control by brushing treatment.

[0137] 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 preparing a liquid crystal cell by a known method to produce a liquid crystal display element.

[0138] As a method for making a liquid crystal box, there can be given as an example: preparing a pair of substrates with liquid crystal orientation films formed thereon, scattering spacers on the liquid crystal orientation film of one substrate, bonding the other substrate with the liquid crystal orientation film surface facing inside, and sealing by injecting liquid crystal under reduced pressure; a method of sealing by bonding the substrates after dropping liquid crystal on the surface of the liquid crystal orientation film on which the spacers are scattered, etc.

[0139] Liquid crystals may also be mixed with polymerizable compounds that polymerize by ultraviolet irradiation or heat as described above. Examples of polymerizable compounds include compounds having one or more polymerizable unsaturated groups such as acrylate groups or methacrylate groups in the molecule, such as polymerizable compounds represented by the following formulas (M-1) to (M-3).

[0140]

[0141] At this time, 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 polymerizable compound is less than 0.01 parts by mass, the polymerizable compound does not polymerize, and the orientation control of the liquid crystal cannot be performed. If the polymerizable compound becomes more than 10 parts by mass, the unreacted polymerizable compound becomes more, and the residual image characteristics of the liquid crystal display element are reduced. After the liquid crystal box is made, while applying an AC and DC voltage to the liquid crystal box, the polymerizable compound is polymerized by heat and ultraviolet irradiation. Thus, the orientation of the liquid crystal molecules can be controlled.

[0142] The liquid crystal alignment agent of the present invention can also be used in a liquid crystal display element manufactured by the following process, that is, it can also be used in the SC-PVA mode: a liquid crystal layer is provided between a pair of substrates having electrodes, a liquid crystal alignment film containing a polymerizable group polymerized by at least one of active energy rays and heat is arranged between the above pair of substrates, and a voltage is applied between the electrodes. Here, as the active energy ray, ultraviolet rays are preferred. As ultraviolet rays, including the preferred scheme, ultraviolet rays used in the above-mentioned PSA method are applied. In the case of polymerization by heating, the heating temperature is 40 to 120°C, preferably 60 to 80°C. In addition, ultraviolet rays and heating can also be performed simultaneously.

[0143] 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, there can be cited a method of adding a compound containing the polymerizable group to a liquid crystal alignment agent, and a method of using a polymer component containing a polymerizable group. As a specific example of a polymer containing a polymerizable group, there can be cited a polymer obtained by using a diamine having a function of being polymerized by the above-mentioned light irradiation.

[0144] Example

[0145] The present invention will be described in more detail below with reference to Examples, but the present invention is not to be construed as being limited to these Examples.

[0146] The abbreviations of the following compounds, the methods for measuring the properties, and the methods for preparing the measurement samples used therefor are as follows. In addition, unless otherwise specified, the numerical values ​​and the ratios of the numerical values ​​are based on mass.

[0147] <Diamine (a)>

[0148]

[0149] <Diamine (b)>

[0150]

[0151] <Other diamines>

[0152]

[0153] (Boc represents tert-butoxycarbonyl.)

[0154] (Tetracarboxylic dianhydride)

[0155]

[0156] NMP: N-methyl-2-pyrrolidone, BCS: butyl cellosolve.

[0157] THF: tetrahydrofuran.

[0158] [Viscosity]

[0159] The viscosity of the polyamic acid solution was measured at 25° C. using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample amount of 1.1 mL (milliliter) and a conical rotor TE-1 (1°34′, R24).

[0160] [Determination of molecular weight]

[0161] The molecular weights of the polyimide precursor and polyimide were measured as follows 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 Corporation).

[0162] Column temperature: 50°C.

[0163] Eluent: N,N-dimethylformamide (as additives, lithium bromide monohydrate (LiBr·H2O) 30 mmol / L (liter), phosphoric acid / anhydrous crystals (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 ml / L).

[0164] Flow rate: 1.0 ml / min.

[0165] Standard samples for preparing the calibration curve: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000 and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight; about 12,000, 4,000 and 1,000) (manufactured by Polymer Laboratory).

[0166] [Determination of Imidization Ratio]

[0167] Add polyimide powder (20 mg) to an NMR (nuclear magnetic resonance) sample tube (NMR standard sampling tube, φ5 (manufactured by Kusano Scientific Co., Ltd.)), add deuterated dimethyl sulfoxide (DMSO-d6, 0.05 mass% TMS (tetramethylsilane) mixture) (0.53 ml), and apply ultrasound to completely dissolve it. The solution was measured by 500 MHz proton NMR in an NMR measuring machine (JNW-ECA500) (manufactured by JEOL DATUM Co., Ltd.). The imidization rate was calculated as follows: the proton derived from the structure that does not change before and after imidization is determined as the reference proton, and the peak integral value of the proton derived from the NH group of the amic acid appearing near 9.5 to 10.0 ppm is used to calculate it using the following formula.

[0168] Imidization rate (%) = (1-α·x / y) × 100

[0169] In the above formula, x is the peak integral value of protons derived from NH groups of amic acid, y is the peak integral value of reference protons, and α is the ratio of the number of reference protons to protons of one NH group of amic acid in the case of polyamic acid (imidation ratio 0%).

[0170] <Synthesis of diamine DA-v-7>

[0171] Compound [DA-v-7] was synthesized according to the following scheme. "MeO" represents a methoxy group.

[0172]

[0173] (Synthesis of Compound 3 (Mixture of 3a and 3b))

[0174] Magnesium (15.39 g, 63.3 mmol, 1.5 eq.) was added to a four-necked flask, and after vacuum drying for 1 hour in a vacuum pump, THF (100 g) was added using a syringe and stirred at room temperature. Next, a solution of compound 1 (100 g, 42.2 mmol) in THF (300 g) was slowly added dropwise at a rate of about stable reflux. Then, the reaction solution was 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 addition was completed, the temperature of the reaction solution was returned to room temperature, and stirring was carried out at room temperature for 3 hours. Then, toluene (1 L) was added to dilute the reaction solution, and the reaction solution was cooled to 0°C again, and a 10% acetic acid solution (500 g) was slowly added dropwise.

[0175] Next, the water layer was removed by liquid separation, and the organic layer was washed with saturated saline (1 L), saturated sodium bicarbonate aqueous solution (1 L), and saturated saline (1 L), and the organic layer was dried with anhydrous magnesium sulfate. Then, the mixture was filtered and distilled off using an evaporator to obtain crude crystals (172 g) of compound 3. The obtained crude crystals were directly used for the following reaction.

[0176] (Synthesis of Compound 4)

[0177] 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 toluene used was distilled off in an evaporator, and the solution was stirred at room temperature to precipitate solids. The obtained solids were filtered to obtain crystals of compound 4 (yield 150 g, yield 91%).

[0178] (Synthesis of Compound 5 (5a, 5b mixture))

[0179] A mixture of compound 4 (108 g, 276 mmol), 5% palladium carbon (water-containing 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 using celite, and the celite was washed with 1 L of toluene. The filtrate was concentrated under reduced pressure, and as a result, the target compound 5 (yield 103.3 g, yield 95%) was obtained.

[0180] (Synthesis of Compound 6)

[0181] At 0°C, under nitrogen substitution, BBr3 (1.0M-CH2Cl2, 243mL, 1.01mol) was added dropwise to a dichloromethane (800mL) solution of compound 5 (95.4g, 243mmol). After the addition, stir at 0°C for 2 hours. After the reaction is completed, add a small amount of the reaction solution to distilled water each time. Extract with ethyl acetate (1L), and wash the extract twice with 500mL of distilled water. After drying the organic layer with magnesium sulfate, the solvent was distilled off under reduced pressure. The obtained crude product was recrystallized in ethanol, filtered, and washed with ethanol. As a result, the target compound 6 (yield 18.6g, yield 21%) was obtained.

[0182] (Synthesis of Compound 8)

[0183] 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), a toluene (20 g) solution of compound 7 (5.35 g, 26.4 mmol) was added dropwise under reflux. After the addition, the mixture was stirred overnight under 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. After the organic layer was dried with anhydrous magnesium sulfate, the solvent was distilled off 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%).

[0184] (Synthesis of DA-v-7)

[0185] A mixture of compound 8 (12.2 g, 22.4 mmol), 5% palladium carbon (water-containing product, 1.22 g, 10 wt%), and dioxane (120 g) was stirred at 60°C for 4 hours in the presence of hydrogen. After the reaction was completed, nitrogen substitution was performed and the mixture was filtered using diatomaceous earth while maintaining the temperature at 60°C. The filtrate was distilled under reduced pressure to remove the solvent, and as a result, a crude product was obtained. The crude product was recrystallized from 2-propanol / ethyl acetate (2:1) to obtain the target DA-v-7 (yield 8.0 g, yield 74%).

[0186] 1H-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).

[0187] <Synthesis of diamine [DA-n-10]>

[0188] Compound [DA-n-10] was synthesized according to the following scheme.

[0189]

[0190] (Synthesis of Compound [1])

[0191] N, N-dimethylformamide (216 g) and potassium carbonate (33 g, 239 mmol) were added to tert-butyl (5-hydroxy-1-naphthyl) carbamate (27.0 g, 104 mmol) and stirred at 80°C. Then, a solution of 1, 2-bis (4-methylbenzenesulfonate) -1, 2-ethylene glycol (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 mixed solution was filtered using a Buchner funnel to obtain sticky black purple crystals (93 g). N,N-dimethylformamide was added to the obtained crude product, heated at 80°C to dissolve, and crystallized from methanol while cooling to room temperature, followed by filtration and drying to obtain compound [1] (yield: 28.0 g, 51.4 mmol, yield 67%).

[0192] 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).

[0193] (Synthesis of Compound [DA-n-10])

[0194] 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. Then, trifluoroacetic acid (31.0 g, 313 mmol) was slowly added dropwise using a dropping funnel, and the mixture was heated and stirred at 50°C for 6 hours. As a result, gray crystals were precipitated in the reaction system. After cooling to 25°C, the reaction solution was poured into water (374 g) and filtered. Triethylamine and water were added to the obtained crystals and stirred to release the diamine from the trifluoroacetate. The crystals were filtered again, washed with methanol and then with hexane, and dried to obtain compound [DA-n-10] (yield: 9.30 g, 27.0 mmol, yield 86%).

[0195] 1 H-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).

[0196] [Synthesis of polyamic acid]

[0197] <Synthesis example 1>

[0198] DA-4 (1.66 g, 7.00 mmol), DA-5 (2.89 g, 8.75 mmol), DA-v-6 (5.30 g, 7.00 mmol) and DA-13 (2.43 g, 12.3 mmol) were weighed into a 100 mL four-necked flask equipped with a stirring device, and NMP (49.1 g) was added and stirred to dissolve. DC-3 (7.53 g, 33.6 mmol) was added while stirring the diamine solution, and NMP (30.1 g) was further added, and stirred at 60° C. for 15 hours to obtain a solution of a polyamic acid (A-a-1, viscosity: 649 mPa·s, Mn: 14231).

[0199] <Synthesis Examples 2 to 7>

[0200] Except that the diamine component and the acid dianhydride component were changed as shown in the following Table 1, the same operation as in Synthesis Example 1 was carried out to obtain polymer (polyamic acid) solutions (A-a-2), (A-a-3), (A-b-4), (A-b-5), (A-r-6), and (A-r-7) shown in the following Table 1.

[0201] The viscosity and molecular weight of the polyamic acid obtained in Synthesis Examples 1 to 7 are shown in Table 1 below.

[0202] [Table 1]

[0203]

[0204] [Preparation of Liquid Crystal Alignment Agent]

[0205] <Comparative Example 1>

[0206] NMP (6.0 g) and BCS (8.0 g) were added to the solution (6.0 g) of the polyamic acid (A-a-1) obtained above, and the mixture was stirred at room temperature for 10 hours to prepare a liquid crystal aligning agent (R-1) containing 6% by mass of polyamic acid (A-a-1), 54% by mass of NMP, and 40% by mass of BCS.

[0207] <Comparative Examples 2 and 3>

[0208] Liquid crystal aligning agents (R-2) and (R-3) shown in the following Table 2 were obtained in the same manner as in Comparative Example 1 except that the polyamic acid (A-a-2) and (A-a-3) were respectively changed in place of the polyamic acid (A-a-1).

[0209] <Example 1>

[0210] The polyamic acid (A-a-1) and polyamic acid (A-b-4) prepared above were used to replace the polyamic acid (A-a-1). As shown in Table 2 below, a liquid crystal aligning agent (1) was obtained in which the component ratio (solid content conversion mass ratio) of the polyamic acid (A-a-1) to the polyamic acid (A-b-4) was (A-a-1) / (A-b-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.

[0211] <Examples 2 to 4, Comparative Examples 4 to 9>

[0212] Except having changed the polyamic acid solution into the one shown in the following Table 2, it implemented similarly to Example 1, and obtained the liquid crystal aligning agent (2) to (4) of Example 2 to 4 and the liquid crystal aligning agent (R-4) to (R-9) of Comparative Examples 4 to 9 shown in the following Table 2, respectively.

[0213] In Table 2, the values ​​in parentheses in the polymer composition represent the mixing ratio (mass parts) of each polymer component relative to a total of 100 parts by mass of the polymer components used in the preparation of the liquid crystal aligning agent. For the solid content ratio and the solvent composition ratio, the mixing ratio (mass parts) of the polymer solid component and each organic solvent relative to a total of 100 parts by mass of the polymer solid component and each organic solvent used in the preparation of the liquid crystal aligning agent is represented.

[0214] [Table 2]

[0215]

[0216] [Production of Liquid Crystal Alignment Film]

[0217] The liquid crystal alignment agents prepared in the above-mentioned embodiments were used to prepare a liquid crystal alignment film as described below.

[0218] The liquid crystal alignment agent prepared in the above embodiments was spin-coated on a quartz substrate or a silicon wafer, dried on a hot plate at 70°C for 90 seconds, and then fired in a hot air circulation oven (MB1-1G3030X manufactured by Denko) at 230°C for 20 minutes to form a liquid crystal alignment film with a film thickness of 100 nm.

[0219] [Measurement of Refractive Index of Liquid Crystal Alignment Film]

[0220] Using a spectroscopic ellipsometer (M-2000) (manufactured by JA Woollam), fitting based on the CAUCHY model was performed to measure the refractive index at 250 to 800 nm. The results are shown in Table 3. The refractive index at 550 nm is recorded in Table 3. The case where the refractive index is greater than 1.62 is defined as "good", and the case where the refractive index is less than 1.62 is defined as "poor".

[0221] [Measurement of Transmittance of Liquid Crystal Alignment Film]

[0222] The transmittance at 380 to 800 nm was measured using an ultraviolet visible spectrophotometer (manufactured by Shimadzu Corporation) (UV-2600). The results are shown in Table 3. Table 3 shows the average value of the transmittance at 380 to 800 nm.

[0223] A measuring box was made using two quartz substrates. A liquid crystal alignment film was formed on one of the two substrates, and the surface on which the liquid crystal alignment film was formed was placed inside, and a quartz substrate without a liquid crystal alignment film was attached. A refractive liquid (contact liquid, manufactured by Shimadzu Equipment Manufacturing Co., Ltd.) was inserted between them using a pipette to make a measuring box. The refractive liquid was used from 11 types with a 0.01 scale from 1.60 to 1.70 according to their respective refractive indices.

[0224] The case where the transmittance was more than 99.0% was evaluated as "good", and the case where the transmittance was 99.0% or less was evaluated as "poor".

[0225] [Table 3]

[0226]

[0227] It should be noted that all the contents of the specification, claims, and abstract of Japanese Patent Application No. 2019-173298 filed on September 24, 2019 are cited herein and introduced as a disclosure of the specification of the present invention.

Claims

1. A liquid crystal alignment agent, characterized in that: Contains the following components (A) and (B), (A) component: at least one polymer (A) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (a), and a polyimide which is an imide product of the polyimide precursor, wherein the diamine (a) has at least one selected from the group consisting of structures represented by the following formulae (S1) to (S3), (B) component: at least one polymer (B) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (b) represented by the following formula (2), and a polyimide which is an imidation product of the polyimide precursor, X 1 and X 2 Each independently represents a single bond, -(CH2) a -, -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -COO-, -OCO- or -((CH2) a1 -A1) m1 -, said -(CH2) a -, a is an integer of 1 to 15, and the -((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, a plurality of a1s and A1s each independently have the above definition; G 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 is optionally substituted by an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms, or a fluorine atom; m and n are each independently integers 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, forming R 1 Any hydrogen atom of is optionally substituted by a fluorine atom, -X 3 -R 2 (S2) X 3 represents a single bond, -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2O-, -COO- or -OCO-; R 2 represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, forming R 2 Any hydrogen atom of is optionally substituted by a fluorine atom, -X 4 -X 3 (S3) X 4 Represents -CONH-, -NHCO-, -O-, -CH2O-, -OCH2-, -COO- or -OCO-; R 3 It indicates a structure with a steroidal skeleton, A1 and A2 each independently represent a divalent condensed ring group optionally having a substituent, wherein the condensed ring group is a divalent group formed by removing two hydrogen atoms from a naphthalene ring; L represents a single bond, -(CH2) n -、-O-(CH2) n -O-, -O-(CH2) n -、-S-(CH2) n -S- or -S-(CH2) n -, of which (CH2) n wherein n is an integer of 1 to 20; and m and n are each independently an integer of 1 to 3.

2. The liquid crystal alignment agent according to claim 1, wherein The diamine (a) is a diamine represented by the following formula [1] or formula [2], X represents a single bond, -O-, -C(CH3)2-, -NH-, -CO-, -(CH2) m -, -SO2-, -O-(CH2) m -O-, -O-C(CH3) m -、-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 -SO2-; m is an integer of 1 to 8; Y represents any structure in the formulae (S1) to (S3), and the two Ys in the formula [2] are optionally the same or different.

3. The liquid crystal alignment agent according to claim 2, wherein: The diamine represented by the formula [1] is the following formula [S-1] to [S-18], n is an integer from 1 to 20, 4. The liquid crystal alignment agent according to claim 2, wherein: The diamine represented by the formula [2] is the following formula [W-1] to [W-6], X p1 ~X p8 Each independently is -(CH2) a -, -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-, the -(CH2) a -, a is an integer from 1 to 15; X s1 ~X s4 Each independently represents -O-, -CH2O-, -OCH2-, -COO- or -OCO-; X a ~X f Indicates -O-, -NH-, -O-(CH2) m -O-, -C(CH3)2-, -CO-, -COO-, -CONH-, -(CH2) m -, -SO2-, -O-C(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-;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; and m is an integer of 1 to 8.

5. The liquid crystal aligning agent according to claim 1 or 2, wherein In the formula (2), m and n are 1 or 2.

6. The liquid crystal aligning agent according to claim 1 or 2, wherein: The polyimide precursor of at least one of the polymer (A) and the polymer (B) is obtained by a polymerization reaction of a diamine component and a tetracarboxylic acid component, wherein the diamine component contains the diamine (a) or the diamine (b), and the tetracarboxylic acid component contains tetracarboxylic dianhydride represented by the following formula (3) or a derivative thereof, X represents a structure selected from the group consisting of the following (x-1) to (x-13), R 1 ~R 4 Each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom or a phenyl group; R 5 and R 6 Each independently represents a hydrogen atom or a methyl group; j and k each independently represent an integer of 0 or 1; A1 and A2 each independently represent a single bond, -O-, -CO-, -COO-, a phenylene group, a sulfonyl group, or an amide group; and the two A2s are optionally the same or different; *1 is a bond bonded to the anhydride group of one side, and *2 is a bond bonded to the anhydride group of the other side.

7. The liquid crystal alignment agent according to claim 6, 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).

8. The liquid crystal aligning agent according to claim 1 or 2, wherein The content of the component (A) and the component (B) is contained so that the mass ratio (A) / (B) is 5 / 95 to 80 / 20. 9 . A liquid crystal alignment film formed using the liquid crystal aligning agent according to claim 1 . 10 . A liquid crystal display element comprising the liquid crystal alignment film according to claim 9 .

11. A method for manufacturing a liquid crystal display element, which is the following method: The liquid crystal alignment agent described in any one of claims 1 to 8 is applied on a pair of substrates having a conductive film to form a coating film, and the coating films are arranged opposite to each other with a layer of liquid crystal molecules therebetween to form a liquid crystal box, and the liquid crystal box is irradiated with light while a voltage is applied between the conductive films of the pair of substrates.

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