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

Abstract

The present application provides a liquid crystal alignment agent containing a polymer (P) comprising at least one selected from the group consisting of a polyimide precursor obtained by using a diamine component comprising a diamine (1) represented by the following formula (1), and a polyimide. (Ar represents a phenylene group, Q represents a divalent organic group comprising at least one naphthalene ring, Q is bonded to two oxygen atoms at benzene rings constituting the at least one naphthalene ring, respectively, and the benzene ring bonded to one of the oxygen atoms is different from the benzene ring bonded to the other of the oxygen atoms. Any hydrogen atom on the above phenylene group is optionally substituted with at least one selected from the group consisting of 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, and a fluorine atom.)

Description

Technical Field

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

[0002] Liquid crystal display (LCD) elements are widely used in applications ranging from small devices like mobile phones and smartphones to larger applications such as televisions and monitors. An LCD element is typically configured by arranging a pair of electrode substrates opposite each other with a predetermined gap (a few μm), and sealing liquid crystal between the electrode substrates. A display is achieved by applying a voltage to the transparent conductive films constituting the electrodes of the electrode substrates. These LCD elements possess a liquid crystal alignment film, essential for controlling the alignment of the liquid crystal molecules.

[0003] On the other hand, various driving methods are being developed for liquid crystal display elements, including different electrode structures and the physical properties of the liquid crystal molecules used. For example, various modes are known, such as TN (Twisted Nematic), STN (Super Twisted Nematic), VA (Vertical Alignment), IPS (In-Plane Switching), and FFS (fringe field switching).

[0004] Among them, VA (vertical alignment) liquid crystal display elements have a wide viewing angle, fast response speed, and high contrast. In addition, the manufacturing process does not require brushing and polishing. Therefore, they are widely used, especially in televisions and monitors where large-scale applications are required.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2008 / 117615

[0008] Patent Document 2: Japanese Patent Application Publication No. 2008-76950 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] Furthermore, the aforementioned transparent conductive film in liquid crystal display elements is typically formed as a composition (ITO) with indium oxide as the main component and a few percent tin oxide doped into it. However, its refractive index differs from that of the liquid crystal alignment film, exhibiting a higher value. Therefore, when attempting to transmit light from the display light source through the electrode substrate, the light is reflected at the boundary 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 adequately obtained, leading to a decrease in display brightness.

[0011] In particular, in recent years, ultra-high-definition panels such as 4K and 8K have been developed. However, the proportion of black matrix (BM) and TFT (Thin Film Transistor) in these panels is increasing, which will reduce the aperture ratio of the panel. Therefore, improving the transmittance of the display is receiving attention.

[0012] Therefore, considering that the aforementioned undesirable situation could be eliminated simply by reducing the difference between the refractive index of the transparent conductive film and the refractive index of the liquid crystal alignment film, the inventors conducted various studies on the forming materials of the liquid crystal alignment film in order to improve its refractive index. Specifically, in order to improve the refractive index of the liquid crystal alignment film, the types of polymers contained in various liquid crystal alignment agents that form the liquid crystal alignment film were explored.

[0013] As a result, it was clarified that by selecting specific polymers, liquid crystal alignment films with refractive indices similar to those of transparent conductive films can be obtained. However, on the other hand, the polymers that form liquid crystal alignment films with high refractive indices do not have very good solubility in the solvent components of liquid crystal alignment agents. Therefore, there is a tendency for poor storage stability of liquid crystal alignment agents and poor coating (printability) of substrates, indicating that there is room for further improvement.

[0014] The object of the present invention is, in view of the above, to provide a liquid crystal alignment agent containing components with good solubility and capable of forming a liquid crystal alignment film with a high refractive index, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film.

[0015] Solution for solving the problem

[0016] In order to solve the above problems, the inventors conducted in-depth research and found that liquid crystal alignment agents containing polymers with specific structures are effective in achieving the above objectives, thus completing the present invention.

[0017] The present invention provides a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film. The liquid crystal alignment agent is characterized in that it contains a polymer (P), the polymer (P) comprising at least one selected from the group consisting of a polyimide precursor obtained by using a diamine component comprising a diamine (1) (hereinafter also referred to as a specific diamine) as shown in formula (1) below and a polyimide.

[0018] H2N-Ar-OQO-Ar-NH2 (1)

[0019] (Ar represents phenylene, Q represents a divalent organic group containing at least one naphthalene ring, Q is bonded to two oxygen atoms respectively on the benzene ring constituting the at least one naphthalene ring, and the benzene ring bonded to one oxygen atom is different from the benzene ring bonded to the other oxygen atom. Any hydrogen atom on the phenylene ring is optionally substituted with at least one of the following groups: alkyl group having 1 to 3 carbon atoms, alkoxy group having 1 to 3 carbon atoms, fluoroalkyl group having 1 to 3 carbon atoms, fluoroalkoxy group having 1 to 3 carbon atoms, and fluorine atom.)

[0020] Invention Effects

[0021] According to the present invention, a liquid crystal alignment agent is obtained that has good solubility of its constituent components and can form a liquid crystal alignment film with a high refractive index. The liquid crystal alignment film formed by this liquid crystal alignment agent has a high refractive index, thus reducing the difference between the refractive index of the transparent conductive film and the refractive index of the liquid crystal alignment film in the liquid crystal display element, and resulting in a liquid crystal display element with excellent display quality.

[0022] The mechanism by which the above-mentioned effects of the present invention are obtained may not be clear, but the following description may be considered as one of the reasons. That is, it can be considered that in the polymer of the present invention, the naphthalene ring is not placed at the bonding position of the amino group but at the center of the diamine molecule, thus reducing the packing property of the polymer, increasing its solubility, and increasing the refractive index of the liquid crystal alignment film obtained by introducing the naphthalene ring. Detailed Implementation

[0023] Hereinafter, the liquid crystal alignment agent of the present invention, the liquid crystal alignment film obtained from the liquid crystal alignment agent, and the liquid crystal display element having the liquid crystal alignment film will be described in detail. The description of the necessary conditions for the construction described below is an example of an embodiment of the present invention and is not specific to these contents.

[0024] In the following explanation, Boc represents tert-butoxycarbonyl. Furthermore, examples of "halogen atoms" include: fluorine, chlorine, bromine, iodine, etc.

[0025] (Liquid crystal alignment agent)

[0026] The liquid crystal alignment agent of the present invention contains a polymer (P) and may also contain other components as needed.

[0027] (Polymer (P))

[0028] The polymer (P) comprises at least one selected from the group consisting of a polyimide precursor obtained using a diamine component and a polyimide.

[0029] The polymer (P) is at least one selected from the group consisting of polyimide precursors and polyimides, and may be one component or two or more components.

[0030] (Diamine component)

[0031] The diamine component comprises the diamine (1) shown in the following formula (1).

[0032] H2N-Ar-OQO-Ar-NH2 (1)

[0033] (In equation (1) above, Ar and Q are the contents as defined above.)

[0034] From the viewpoint of achieving the effects of the present invention, the number of carbon atoms in Q is preferably 10 to 40, and Q is more preferably a divalent organic group with 10 to 40 carbon atoms as shown in the following formula (f).

[0035]

[0036] (A1 and A2 are each independently a naphthalene ring optionally having a substituent. X1 and X2 are each independently a single bond, an oxygen atom, or a sulfur atom. Y is an alkylene group having 1 to 8 carbon atoms, or a divalent organic group containing an oxygen atom or a sulfur atom between carbon-carbon bonds of an alkylene group having 1 to 8 carbon atoms. m is an integer from 0 to 2, and n is an integer 0 or 1. * indicates a bonded bond.)

[0037] The naphthalene ring may optionally have substituents. Examples of substituents that may optionally be present in the naphthalene ring include alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, and halogen atoms. X1 and X2 are preferably oxygen atoms.

[0038] As a preferred specific example of the diamine (1) shown in the above formula (1), the following formulas (d-1) to (d-2) can be listed.

[0039]

[0040] When the polymer (P) contained in the liquid crystal alignment agent of the present invention is applied to a liquid crystal alignment agent for liquid crystal display elements in TN, STN, VA, PSA (Polymer Sustained Alignment), and SC-PVA (Patterned Vertical Alignment) modes, in addition to containing the diamine shown in formula (1) above, it is preferable to also contain a diamine (s) as a constituent component, wherein the diamine (s) has at least one of the following groups of partial structures formed by formulas (S1) to (S3). In the polymer (P), the diamine (s) may be a constituent component selected from at least one of the following groups of polyimide precursors containing diamine (1) as a constituent component and polyimides, or it may be a constituent component selected from at least one of the following groups of polyimide precursors containing diamine (1) as a constituent component, which is different from at least one of the following groups of polyimide precursors containing diamine (1) as a constituent component.

[0041]

[0042] In equation (S1), X 1 and X 2 Each can be used independently to represent a single bond and -(CH2). a -(a is an integer from 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -N(CH3)CO-, -NH-, -O-, -COO-, -OCO-, -((CH2) a1 -A1) m1 - or - (A1-(CH2)) a1 ) m1 — [a1 is an integer from 1 to 15, A1 represents an oxygen atom, -COO-, or -OCO-, and m1 is an integer from 1 to 2. When m1 is 2, the multiple a1s are independent, and the multiple A1s are independent.] G 1 and G 2 Each group independently represents a divalent cyclic group selected from divalent aromatic groups having 6 to 12 carbon atoms and divalent alicyclic groups having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group is optionally substituted with at least one group selected from the group consisting of alkyl groups having 1 to 3 carbon atoms, alkoxy groups having 1 to 3 carbon atoms, fluorinated alkyl groups having 1 to 3 carbon atoms, fluorinated alkoxy groups having 1 to 3 carbon atoms, and fluorine atoms. m and n are each independently integers from 0 to 3, and the sum of m and n is 1 to 6. From the viewpoint of improving liquid crystal alignment, the sum of m and n is preferably 2 to 6, more preferably 2 to 4. R 1 Representing 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 R1 Any hydrogen atom may be optionally replaced by a fluorine atom.

[0043] Furthermore, as G 1 G 2 Examples of divalent cyclic groups in cyclohexene include cyclopropylene, cyclohexene, and phenylene. Any hydrogen atom on these cyclic groups may be optionally replaced 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.

[0044] -X 3 -R 2 (S2)

[0045] In equation (S2), X 3 Represents a single bond, -CONH-, -NHCO-, -CON(CH3)-, -N(CH3)CO-, -NH-, -O-, -CH2O-, -COO-, or -OCO-. R 2 Representing 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 may be optionally replaced by a fluorine atom.

[0046] Furthermore, from the perspective of improving liquid crystal alignment, R 2 Preferably, the alkyl group has 3 to 20 carbon atoms or the alkoxyalkyl group has 2 to 20 carbon atoms.

[0047] -X 4 -R 3 (S3)

[0048] In equation (S3), X 4 This represents -CONH-, -NHCO-, -O-, -COO-, -OCO-, and -((CH2)-. a1 -A1) m1 - or - (A1-(CH2)) a1 ) m1 — [a1 is an integer from 1 to 15, A1 represents an oxygen atom, -COO-, or -OCO-, and m1 is an integer from 1 to 2. When m1 is 2, the multiple a1s are independent, and the multiple A1s are independent.] R 3 This indicates a structure with a steroidal framework. Furthermore, R... 3 Preferably, the structure contains cholesteryl, cholesterol, or lanostane.

[0049] As a preferred example of formula (S1), the following formulas [S1-x1]~[S1-x7] can be listed.

[0050]

[0051] In the above formula, R 1 This refers to 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. X p It represents -(CH2) a - (a is an integer from 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-. A1 represents an oxygen atom or -COO-* (where the bond marked with "*" is with (CH2). a2 (bonding), A2 represents an oxygen atom or *-COO- (where the bond marked with "*" is bonded to (CH2). a2 (bonding), a1 and a3 are independent integers 0 or 1, a2 is an integer from 1 to 10, and Cy represents 1,4-cyclohexene or 1,4-phenylene.

[0052] As a preferred specific example of the above formula (S3), the following formula [S3-x] can be listed. It should be noted that in formula [S3-x], X represents formula [X1], formula [X2], or -CH2-O-, Col represents formula [Col1], formula [Col2], or formula [Col3], and G represents formula [G1], formula [G2], formula [G3], or formula [G4]. In the formula, "Me" represents a methyl group. * represents a bond.

[0053]

[0054] As a preferred diamine(s) having the partial structures shown in formulas (S1) to (S3) above, it is preferable to have a diamine having the partial structures shown in formulas (S1) to (S3) above and having at least one benzene ring. As diamine(s), diamines shown in formula (d1) or formula (d2) below can be listed.

[0055]

[0056] In equations (d1) and (d2), Y represents the side chain structure shown in equations (S1) to (S3) above. Furthermore, X represents a single bond, -O-, -C(CH3)2-, -NH-, -CO-, -COO-, -CONH-, or -(CH2). m -, -SO2-, -O-(CH2) m -O-, -O-C(CH3)2-, -CO-(CH2) m -、-CO-(CH2) m -CO-, -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-. m is an integer from 1 to 8. In the above formula (d2), the two Ys can be either the same or different from each other.

[0057] As preferred examples of the diamine of the above formula (d1), the following formulas (d1-1) to (d1-18) can be listed.

[0058]

[0059] (n is an integer from 1 to 20.)

[0060]

[0061] As the diamine represented by the above formula (d2), structures selected from the group consisting of the following formulas (d2-1) to (d2-6) can be listed.

[0062]

[0063] In the above formula, X p1 ~X p8 It represents -(CH2) a - (a is an integer from 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-. X s1 ~X s4 Each can be represented independently as -O-, -COO-, or -OCO-. X a ~X f This indicates a single bond, -O-, -NH-, or -O-(CH2). m -O- (m is an integer from 1 to 8). R 1a ~R 1h Each can be independently represented as 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.

[0064] (Manufacturing of polymer (P))

[0065] The polymer (P) contained in the liquid crystal alignment agent of the present invention may also be composed of one or more components of a polyimide precursor and a polyimide as an imide derivative of the polyimide precursor. Here, the polyimide precursor is a polymer such as polyamic acid or polyamic acid ester that can be imidized to obtain a polyimide. More preferred embodiments of the polymer (P) are listed below, but the present invention is not limited thereto.

[0066] The polymer (hereinafter also referred to as a copolymer) is selected from at least one polymer (p-1) and polymer (p-2) consisting of a polyimide precursor obtained by using a diamine component containing the diamine (1) and the diamine (s) described above, and a polyimide as an imide derivative of the polyimide precursor; the polymer (p-1) is selected from at least one polymer (p-2) consisting of a polyimide precursor obtained by using a diamine component containing the diamine (1) described above, and a polyimide as an imide derivative of the polyimide precursor; the polymer (p-2) is selected from at least one polymer (p-2) consisting of a polyimide precursor obtained by using a diamine component containing the diamine (s) described above, and a polyimide as an imide derivative of the polyimide precursor.

[0067] The copolymers or blends mentioned above can be used alone or in combination.

[0068] Polyamic acid (P), which is the polyimide precursor of the above polymer (P), can be obtained by polymerization of a diamine component containing the above diamine (1) (preferably a diamine component containing diamine (s) in addition to the above diamine (1)) and a tetracarboxylic acid component.

[0069] In this case, the amount of diamine (1) used relative to the diamine component reacting with the tetracarboxylic acid component is preferably 1 to 100 mol%, more preferably 1 to 99 mol%, and even more preferably 5 to 95 mol%.

[0070] When diamine(s) is used in addition to the diamine(1) mentioned above, the amount of diamine(s) used is preferably 1 to 99 mol% relative to the diamine component that reacts with the tetracarboxylic acid component, and more preferably 1 to 95 mol%.

[0071] The diamine component used in the manufacture of the above-mentioned polyamic acid (P) may also include diamines other than diamine (1) and diamine (s) (hereinafter also referred to as other diamines). Examples of other diamines are listed below, but the present invention is not limited thereto.

[0072] p-Phenylidene diamine, m-phenylene diamine, 4-(2-(methylamino)ethyl)aniline, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, and diamine compounds of formulas (3b-1) to (3b-4) below, including carboxyl-containing diamines; 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether; 1,2-bis(4-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,2-bis(4-) 1,2-bis(4-amino-2-methylphenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 4-(2-(4-aminophenoxy)ethoxy)-3-fluoroaniline, di(2-(4-aminophenoxy)ethyl) ether, 4-amino-4'-(2-(4-aminophenoxy)ethoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 1,4-diaminonaphthalene, 1 5-Diaminonaphthalene, 2,6-Diaminonaphthalene, 2,7-Diaminonaphthalene, diamines represented by formulas (nh-1) to (nh-6), diamines with urea bonds such as 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2'-bis(4-aminophenyl)propane, and 1,3-bis(4-aminophenylethyl)urea, diamines with photopolymerizable groups at the ends such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallyl aniline, diamines with free radical initiation functions such as formulas (R1) to (R5), 4,4'-diaminobenzophenone, and 3,3'-diaminonaphthalene Diamines with photosensitizing properties, such as benzophenone and 9,9-bis(4-aminophenyl)fluorene, exhibit photosensitizing effects upon light irradiation; 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole; heterocyclic diamines of formulas (z-1) to (z-18); diamines with a diphenylamine skeleton of formulas (Dp-1) to (Dp-9); diamines with the group "-N(Boc)" of formulas (5-1) to (5-10); diamines with an oxazoline structure of formulas (Ox-1) to (Ox-2); and diamines described in International Publication No. 2016 / 125870.

[0073]

[0074] (In equation (3b-1), A) 1 The following symbols represent single bonds: -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)-, or -N(CH3)CO-. m1 and m2 independently represent integers 0 to 4, and m1 + m2 represents integers 1 to 4. In equation (3b-2), m3 and m4 independently represent integers 1 to 5. In equation (3b-3), A... 2 m5 represents a straight-chain or branched alkyl group with 1 to 5 carbon atoms, where m5 represents an integer from 1 to 5. In formula (3b-4), A 3 and A 4 Each of these can independently represent a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)-, or -N(CH3)CO-, where m6 represents an integer from 1 to 4.

[0075]

[0076]

[0077] (n is an integer from 1 to 6.)

[0078]

[0079] Among these, from the viewpoint of obtaining the desired effects of the present invention, the preferred diamines are p-phenylene diamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,N-diallyl aniline, the diamines represented by formulas (R1) to (R5) above, the diamines represented by formulas (z-1) to (z-18) above, the diamines represented by formulas (5-1) to (5-10) above, and the diamines represented by formulas (Ox-1) to (Ox-2) above.

[0080] When other diamines are used in addition to the diamine (1) mentioned above, the amount of the other diamine used is preferably 1 to 99 mol% relative to the total diamine component used, and more preferably 5 to 95 mol%.

[0081] When other diamines are used in addition to the diamines (1) and (s) mentioned above, the amount of diamine (s) used is preferably 98 mol% or less, more preferably 94 mol% or less, relative to the diamine component that reacts with the tetracarboxylic acid component.

[0082] The amount of diamine used as shown in formulas (5-1) to (5-10) above is preferably 5 to 40 mol% relative to the total diamine content used in the manufacture of polyamic acid (P), and more preferably 10 to 40 mol%.

[0083] For liquid crystal display elements using PSA and SC-PVA modes, from the perspective of improving response speed, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, diamines having photopolymerizable groups at the ends, diamines shown in formulas (R1) to (R5) above, and diamines shown in formulas (z-1) to (z-18) above can be used in the manufacture of polyamic acid (P), and the amount used is preferably 1 to 40 mol% relative to the total diamine content used in the manufacture of polyamic acid (P), more preferably 5 to 40 mol%.

[0084] (Tetracarboxylic acid component)

[0085] In the manufacture of the above-mentioned polyamic acid (P), the tetracarboxylic acid component that reacts with the diamine component is not only tetracarboxylic dianhydride, but may also be a derivative of tetracarboxylic dianhydride such as tetracarboxylic acid, tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters, or tetracarboxylic acid dialkyl ester dihalides.

[0086] The aforementioned tetracarboxylic dianhydrides or their derivatives can be categorized as aromatic, aliphatic, or alicyclic tetracarboxylic dianhydrides, or their derivatives. Here, aromatic tetracarboxylic dianhydrides are acid dianhydrides obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to an aromatic ring. Aliphatic tetracarboxylic dianhydrides are acid dianhydrides obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. It is not necessary for the structure to consist solely of a chain hydrocarbon; a portion of the structure may also have an alicyclic or aromatic ring structure.

[0087] Furthermore, alicyclic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to the alicyclic structure. None of these four carboxyl groups are bonded to an aromatic ring. Moreover, it is not necessary for the structure to consist solely of an alicyclic structure; it can also have a chain hydrocarbon structure or an aromatic ring structure in a portion thereof.

[0088] The aforementioned tetracarboxylic dianhydride or its derivative is preferably represented by the following formula (T). That is, the polymer (P) preferably contains a tetracarboxylic acid component containing the tetracarboxylic dianhydride shown in formula (T) as a constituent component.

[0089]

[0090] In equation (T), X represents the structure selected from the group consisting of (x-1)~(x-13) below.

[0091]

[0092] R 1 ~R 4 Each of the following can be independently represented: a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, an alkynyl group with 2 to 6 carbon atoms, a monovalent organic group containing a fluorine atom with 1 to 6 carbon atoms, or a phenyl group. 5 and R 6 Each A1 and A2 independently represents a hydrogen atom or a methyl group. j and k are integers 0 or 1. A1 and A2 independently represent a single bond, an ether bond (-O-), a carbonyl group (-CO-), an ester bond (-COO- or -OCO-), a phenylene group, a sulfonyl group (-SO2-), or an amide group (-CONH- or -NHCO-). *1 represents a bond bonded to the anhydride group of one party, and *2 represents a bond bonded to the anhydride group of the other party. In formula (x-13), the two A2 groups may be optionally the same or different from each other.

[0093] As a more preferred specific example of the above formula (x-1), the following formulas (X1-1) to (X1-6) can be listed. In the formulas, * represents a bond.

[0094]

[0095] As preferred examples of the above equations (x-12) and (x-13), equations (x-14) to (x-29) can be listed below. In the equations, * represents a bond.

[0096]

[0097]

[0098] As a preferred specific example of the tetracarboxylic dianhydride or its derivative shown in the above formula (T), X can be selected from the tetracarboxylic dianhydride or its derivative selected from the above formulas (x-1) to (x-7) and formulas (x-11) to (x-13).

[0099] The proportion of tetracarboxylic acid dianhydride or its derivatives shown in the above formula (T) is preferably 1 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, relative to 1 mole of the total tetracarboxylic acid component used.

[0100] The tetracarboxylic dianhydride and its derivatives used in the manufacture of polyamic acid (P) may also contain tetracarboxylic dianhydrides or their derivatives other than those in formula (T) above.

[0101] The production of polyamic acid (P) is carried out by reacting the aforementioned diamine component with the tetracarboxylic acid component in a solvent via a (condensation) reaction. There are no particular limitations on the solvent used, as long as it dissolves the resulting polymer.

[0102] Specific examples of the solvents mentioned above include: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolinone, etc. Furthermore, when the polymer has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or solvents shown in formulas [D-1] to [D-3] below can be used.

[0103]

[0104] (In formula [D-1], D) 1 In formula [D-2], D represents an alkyl group with 1 to 3 carbon atoms. 2 In formula [D-3], D represents an alkyl group having 1 to 3 carbon atoms. 3 (Refers to alkyl groups with 1 to 4 carbon atoms).

[0105] These solvents can be used alone or in combination. Moreover, even solvents that do not dissolve polymers can be mixed with the aforementioned solvents as long as the resulting polymer does not precipitate.

[0106] When the diamine component and the tetracarboxylic acid component react in a solvent, the reaction can be carried out at any concentration. The total mass percentage of the diamine component and the tetracarboxylic acid component relative to the reaction solution is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration initially, and then additional solvent is added.

[0107] In the reaction, the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic acid component is preferably 0.8 to 1.2. Similar to typical polycondensation reactions, the closer this molar ratio is to 1.0, the larger the molecular weight of the resulting polymer.

[0108] Polyamates, as precursors of polyimides, can be obtained, for example, by the following known methods: [I] reacting the polyamic acid obtained by the above-described synthesis reaction with an esterifying agent; [II] reacting a tetracarboxylic acid diester with a diamine; [III] reacting a tetracarboxylic acid diester dihalide with a diamine, etc.

[0109] [Polyimide]

[0110] The polyimide contained in the liquid crystal alignment agent of the present invention is a polyimide obtained by cyclizing the aforementioned polyimide precursor. In the polyimide, the cyclization rate of the ammonium acid group (also known as the imidization rate) does not necessarily need to be 100%, and can be arbitrarily adjusted according to the application and purpose.

[0111] Methods for obtaining polyimide by imidizing a polyimide precursor include: thermal imidization by directly heating a solution of the polyimide precursor, and catalytic imidization by adding a catalyst to the solution of the polyimide precursor. When thermally imidizing the polyimide precursor in solution, the temperature is 100–400°C, preferably 120–250°C, and preferably the process is carried out while removing water generated by the imidization reaction from the system.

[0112] Catalytic imidization of the polyimide precursor is 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 basic catalyst is 0.5 to 30 molar times, preferably 2 to 20 molar times, of the amide group, and the amount of acid anhydride is 1 to 50 molar times, preferably 3 to 30 molar times, of the amide group. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine, among which pyridine is preferred due to its moderate basicity in promoting the reaction. Examples of acid anhydrides include acetic anhydride, phenyltriglyceridate anhydride, and pyromellitic anhydride, among which acetic anhydride is preferred because it facilitates purification after the reaction. The imidization rate based on catalyst imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[0113] In the case of recovering the generated polyimide from the reaction solution of the imidization of the polyimide precursor, the reaction solution can be precipitated by adding a solvent. Examples of solvents for precipitation include methanol, ethanol, isopropanol, acetone, hexane, butyl cellulose, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer obtained by precipitation in the solvent can be recovered by filtration and then dried at room temperature or under reduced pressure. Furthermore, by repeatedly re-precipitating and recovering the precipitated polymer in a solvent 2 to 10 times, impurities in the polymer can be reduced. Examples of solvents used in this process include alcohols, ketones, and hydrocarbons. Using three or more solvents selected from these sources further improves the purification efficiency and is therefore preferred.

[0114] The weight-average molecular weight (Mw) of the polyimide precursor and polyimide, as determined by gel permeation chromatography (GPC) based on polystyrene, is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC, is preferably 15 or less, more preferably 10 or less. Within this molecular weight range, good orientation of the liquid crystal display element can be ensured.

[0115] <End-capping agent>

[0116] When synthesizing the polymer (P) of this invention, it can also be synthesized by using a suitable capping agent together with the tetracarboxylic acid component and the diamine component as described above. The capped polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by coating and improving the adhesion properties between the sealant and the liquid crystal alignment film.

[0117] Examples of the ends of the polymer (P) in this invention include: amino, carboxyl, anhydride, isocyanate, or derivatives thereof. These ends can be obtained by conventional condensation reactions or by capping the ends using end-capping agents.

[0118] Examples of capping agents include: acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, benzotriac anhydride, compounds shown in formulas (m-1) to (m-6) below, 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynyl phthalic anhydride, etc.; di-tert-butyl dicarbonate, dicarbonate, etc. Dicarbonate compounds such as diallyl ester; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinyl chloride; monoamine compounds such as aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate, and naphthyl isocyanate.

[0119]

[0120] The proportion of the capping agent used relative to 100 moles of the total diamine components used is preferably 0.01 to 20 moles, more preferably 0.01 to 10 moles.

[0121] The proportion of polymer (P) in the liquid crystal alignment agent of the present invention is preferably 30 parts by mass or more, more preferably 30 to 100 parts by mass, and even more preferably 50 to 100 parts by mass, relative to 100 parts by mass of the total polymer contained in the liquid crystal alignment agent.

[0122] (Other ingredients)

[0123] The liquid crystal alignment agent of the present invention is, for example, a liquid composition of a polymer (P) and other components used as needed, preferably dispersed or dissolved in a suitable solvent.

[0124] In the liquid crystal alignment agent of the present invention, for example for the purpose of improving electrical properties, vertical alignment, solution properties, etc., in addition to polymer (P), other polymers (hereinafter also referred to as other polymers) may be contained.

[0125] The proportion of other polymers is preferably 90 parts by mass or less, more preferably 10 to 90 parts by mass, and even more preferably 20 to 80 parts by mass, relative to 100 parts by mass of the total polymers contained in the liquid crystal alignment agent.

[0126] Other polymers are not particularly limited, and examples include: polysiloxanes, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-phenylmaleimide) derivatives, and poly(meth)acrylates as the main backbone. Preferably, at least one polymer is selected from the group consisting of polyamides, polyureas, polyorganosiloxanes, poly(meth)acrylates, and polyesters. It should be noted that two or more other polymers can also be used in combination.

[0127] The liquid crystal alignment agent of the present invention may also contain other components other than those described above as needed. Examples of such components include, for instance, at least one compound selected from the group consisting of crosslinking compounds having substituents and crosslinking compounds having polymerizable unsaturated groups, functional silane compounds, metal chelating compounds, curing accelerators, surfactants, antioxidants, sensitizers, preservatives, and compounds for adjusting the dielectric constant or resistance of the liquid crystal alignment film, wherein the substituents are at least one selected from epoxy groups, isocyanate groups, oxetyl groups, cyclic carbonate groups, block isocyanate groups, hydroxyl groups, and alkoxy groups.

[0128] Preferred specific examples of crosslinking compounds include compounds represented by formulas (CL-1) to (CL-11).

[0129]

[0130] Compounds used to adjust the dielectric constant and resistance of liquid crystal alignment films include monoamines such as 3-aminomethylpyridine, which have nitrogen-containing aromatic heterocycles. When using monoamines with nitrogen-containing aromatic heterocycles, the amount is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, more preferably 0.1 to 20 parts by mass.

[0131] Preferred specific examples of functional silane compounds include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane. Silane compounds include oxy-based silanes, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, tri-(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatepropyltriethoxysilane. When using functional silane compounds, the amount is preferably 0.1 to 30 parts by weight, more preferably 0.1 to 20 parts by weight, relative to 100 parts by weight of the polymer component contained in the liquid crystal alignment agent.

[0132] The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as it uniformly dissolves the polymer components. Specific examples include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactic acid, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide. Amides, 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 (also collectively referred to as "good solvents"), etc. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, or γ-butyrolactone are preferred. The content of the good solvent is preferably 20-99% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 20-90% by mass, and particularly preferably 30-80% by mass.

[0133] Furthermore, the organic solvent contained in the liquid crystal alignment agent is preferably a mixed solvent that, in addition to the solvents mentioned above, also uses a solvent that improves the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent (also known as a poor solvent). Specific examples of the organic solvents used are described below, but are not limited thereto.

[0134] For example, diisopropyl ether, diisobutyl ether, diisobutylmethanol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-Butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0135] Among them, diisobutylmethanol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, or diisobutyl ketone.

[0136] The content of the undesirable solvent is preferably 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. The type and content of the undesirable solvent are appropriately selected according to the coating apparatus, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

[0137] Preferred combinations of solvents, representing good and poor solvents, include: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-dimethyllacticamide and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether. Monobutyl ether acetate; N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether; N,N-dimethyl lactamide and ethylene glycol monobutyl ether; N,N-dimethyl lactamide and propylene glycol diacetate; N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether; N,N-dimethyl lactamide and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4- Hydroxy-4-methyl-2-pentanone and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; Monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutylmethanol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and propylene glycol diacetate; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and diisobutyl ketone; N-ethyl-2-pyrrolidone, γ-butyrolactone and diisobutyl ketone; N-ethyl-2-pyrrolidone, N,N-dimethyllactic acid and diisobutyl ketone, etc.

[0138] The concentration of solid components in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent in the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected considering factors such as viscosity and volatility, and is preferably in the range of 1 to 10% by mass. Particularly preferred ranges of solid component concentration vary depending on the method used to coat the liquid crystal alignment agent onto the substrate. For example, in the case of spin coating, a solid component concentration is particularly preferably in the range of 1.5 to 4.5% by mass. In the case of printing, a solid component concentration of 3 to 9% by mass is particularly preferred, thereby setting the solution viscosity in the range of 12 to 50 mPa·s. In the case of inkjet printing, a solid component concentration of 1 to 5% by mass is particularly preferred, thereby setting the solution viscosity in the range of 3 to 15 mPa·s.

[0139] (Liquid crystal alignment film / Liquid crystal display element)

[0140] The liquid crystal alignment film of the present invention is obtained from the above-described liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used in horizontally aligned or vertically aligned liquid crystal alignment films, and is particularly suitable for vertically aligned liquid crystal display elements such as VA mode or PSA mode (described later). The liquid crystal display element of the present invention includes the above-described liquid crystal alignment film.

[0141] The liquid crystal display element of the present invention includes the liquid crystal alignment film of the present invention.

[0142] An example of a method for manufacturing a liquid crystal display element according to the present invention includes steps (A), (B) and (C).

[0143] Step (A): A step of coating a pair of substrates having a conductive film with the liquid crystal alignment agent of the present invention to form a coating film.

[0144] Process (B): A process in which liquid crystal cells are formed by arranging layers of coating separated by liquid crystal molecules.

[0145] Process (C): A process of irradiating a liquid crystal cell with light while applying a voltage between the conductive films of a pair of substrates.

[0146] The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following steps (1) to (3) or steps (1) to (4).

[0147] (1) Process of coating liquid crystal alignment agent onto substrate

[0148] The liquid crystal alignment agent of the present invention is coated onto one side of a substrate having a patterned transparent conductive film using a suitable coating method such as a roller coater, spin coater, printing, or inkjet printer. As for the substrate, there are no particular limitations as long as it is a highly transparent substrate; it can be used in conjunction with glass substrates, silicon nitride substrates, or plastic substrates such as acrylic substrates or polycarbonate substrates. Furthermore, in reflective liquid crystal display elements, if only a single-sided substrate is used, an opaque material such as a silicon wafer can be used, and in this case, the electrodes can be made of light-reflecting materials such as aluminum.

[0149] (2) The process of firing the coating film

[0150] After the liquid crystal alignment agent is coated, a preheating (pre-baking) process is preferably performed first to prevent liquid sagging of the alignment agent. The pre-baking temperature is preferably 30–200°C, more preferably 40–150°C, and particularly preferably 40–100°C. The pre-baking time is preferably 0.25–10 minutes, more preferably 0.5–5 minutes. Furthermore, to allow the solvent to evaporate, a further heating (post-baking) process is preferably performed. The post-baking temperature is preferably 80–300°C, more preferably 120–250°C. The post-baking time is preferably 5–200 minutes, more preferably 10–100 minutes. The film thickness thus formed is preferably 5–300 nm, more preferably 10–200 nm.

[0151] The coating formed in step (1) above can be used directly as a liquid crystal alignment film, or the coating can be subjected to an alignment capability imparting treatment. Examples of alignment capability imparting treatments include: brushing treatment by rubbing the coating in a certain direction with a roll of cloth made of fibers such as nylon, rayon, or cotton; and light alignment treatment by irradiating the coating with polarized or unpolarized radiation.

[0152] In photoalignment processing, the radiation used to irradiate the coating can be, for example, ultraviolet light and visible light with wavelengths ranging from 150 to 800 nm. The radiation can be linearly polarized or partially polarized. Furthermore, when using linearly or partially polarized radiation, irradiation of the substrate surface can be performed vertically, obliquely, or a combination thereof. When irradiating unpolarized radiation, the irradiation direction is set to an oblique direction.

[0153] (3) Process of forming liquid crystal layer

[0154] (3-1) Case of VA type liquid crystal display element

[0155] As described above, two substrates with liquid crystal alignment films are prepared, and liquid crystal is disposed between the two opposing substrates. Specifically, two methods can be listed below. The first method is a known method. First, the two substrates are arranged opposite each other with a gap (cell gap) between them, with each liquid crystal alignment film facing each other. Next, the peripheral portions of the two substrates are bonded together using a sealant, and a liquid crystal composition is injected into the cell gap defined by the substrate surface and the sealant until it contacts the film surface, and then the injection hole is sealed.

[0156] Furthermore, the second method is called the ODF (One Drop Fill) method. In this method, a UV-curable sealant is applied, for example, to a predetermined location on one of two substrates on which a liquid crystal alignment film has been formed. Then, a liquid crystal composition is dropped onto several predetermined locations on the surface of the liquid crystal alignment film. Next, the other substrate is bonded with the liquid crystal alignment films facing each other, and the liquid crystal composition is spread across the entire surface of the substrate, contacting the film surface. Then, the entire surface of the substrate is irradiated with UV light to cure the sealant. Ideally, in any method, the liquid crystal composition used is further heated to an isotropic temperature and then slowly cooled to room temperature, thereby removing the flow alignment during liquid crystal filling.

[0157] The liquid crystal alignment agent of the present invention is also preferably used in liquid crystal display elements (hereinafter also referred to as PSA type liquid crystal display elements) manufactured by the following process: having a liquid crystal layer between a pair of substrates having electrodes, disposing a liquid crystal composition containing a polymerizable compound that is polymerized by at least one of active energy rays and heat between the pair of substrates, applying a voltage between the electrodes, and polymerizing the polymerizable compound by at least one of irradiation by active energy rays and heat.

[0158] Furthermore, the liquid crystal alignment agent of the present invention can also be used in liquid crystal display elements (hereinafter also referred to as SC-PVA type liquid crystal display elements) manufactured by the following process: a liquid crystal layer is provided between a pair of substrates having electrodes, a liquid crystal alignment film containing polymeric groups polymerized by at least one of active energy rays and heat is disposed between the pair of substrates, and a voltage is applied between the electrodes.

[0159] (3-2) Manufacturing of PSA-type liquid crystal display elements

[0160] The same applies as described above (3-1) except that a liquid crystal composition containing a polymerizable compound may be injected or dropped. Examples of polymerizable compounds include those shown in formulas (M-1) to (M-7).

[0161]

[0162] (3-3) Manufacturing of SC-PVA type liquid crystal display elements

[0163] Following the same procedure as described in (3-1), the liquid crystal display element can also be manufactured using the ultraviolet irradiation process described later. According to this method, similar to the manufacture of the PSA-type liquid crystal display element, a liquid crystal display element with excellent response speed can be obtained with a small amount of light irradiation. The compound having polymerizable groups can be a compound having one or more polymerizable unsaturated groups such as acrylate or methacrylate groups within its molecule, as shown in formulas (M-1) to (M-7) above. Its content relative to 100 parts by mass of the total polymer component is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass. Furthermore, the aforementioned polymerizable groups can also be present in polymers used as liquid crystal alignment agents. Examples of such polymers include polymers obtained by reacting a diamine component containing a diamine terminally having the aforementioned photopolymerizable groups.

[0164] (4) Process of irradiating with ultraviolet light

[0165] The liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates obtained in (3-2) or (3-3) above. The applied voltage can be, for example, DC or AC of 5-50V. Furthermore, the irradiation light can be, for example, ultraviolet light or visible light with wavelengths of 150-800nm, preferably ultraviolet light with wavelengths of 300-400nm. The light source can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. The irradiation intensity is preferably 1000-200000 J / m². 2 More preferably, it is 1000 to 100000 J / m 2 .

[0166] Furthermore, a liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include: a polarizing plate made by sandwiching a polarizing film called an "H film" between a cellulose acetate protective film; or a polarizing plate made of the H film itself, wherein the H film is formed by absorbing iodine while extending and oriented polyvinyl alcohol.

[0167] The liquid crystal display element of the present invention can be effectively used in various devices, such as clocks, portable game consoles, word processors, laptops, car navigation systems, portable camcorders, PDAs (Personal Digital Assistants), digital cameras, mobile phones, smartphones, various monitors, LCD TVs, information displays, and other display devices. Furthermore, the polymer composition contained in the aforementioned liquid crystal alignment agent can also be used for liquid crystal alignment films for retardation films, liquid crystal alignment films for scanning antennas, liquid crystal array antennas, or liquid crystal alignment films for transmission-scattering type liquid crystal dimming elements, or for other applications, such as protective films for color filters, gate insulating films for flexible displays, and substrate materials.

[0168] Example

[0169] The following examples illustrate the invention in detail, but the invention is not to be construed as being limited to these examples. The abbreviations of the compounds and the methods for determining their properties are described below.

[0170] (Tetracarboxylic acid dianhydride)

[0171] DC-1 to DC-3: Compounds represented by the formulas (DC-1) to (DC-3) below.

[0172]

[0173] (Diamine)

[0174] DA-1 to DA-11: Compounds represented by the following formulas (DA-1) to (DA-11).

[0175]

[0176] The compound represented by formula (DA-1) was synthesized by the synthetic method described in the non-patent literature (High Performance Polymers, vol.31(9-10), p1043-1053(2019)).

[0177] The compound represented by formula (DA-2) was synthesized by the synthetic method described in the non-patent literature (Separation and Purification Technology, vol. 235, 116218 (2020)).

[0178] The compound represented by formula (DA-3) was synthesized by the synthetic method described in non-patent literature (Polymer Science, Series B: PolymerChemistry, vol.60(3), 273-282(2018)).

[0179] (solvent)

[0180] NMP: N-methyl-2-pyrrolidone.

[0181] BCS: Butyl cellosolve (ethylene glycol monobutyl ether).

[0182] [Viscosity]

[0183] The measurement was performed using a TVE-22H type E viscometer (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL and a conical rotor TE-1 (1°34', R24), at a temperature of 25°C.

[0184] [Determination of molecular weight]

[0185] The determination was performed using a room-temperature gel permeation chromatography (GPC) apparatus (GPC-101, manufactured by Showa Denko Corporation) and chromatographic columns (GPCKD-803, GPC KD-805, manufactured by Showa Denko Corporation), as described below.

[0186] Column temperature: 50℃.

[0187] Eluent: N,N-dimethylformamide (as additives, lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, anhydrous phosphoric acid (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L).

[0188] Flow rate: 1.0 mL / min.

[0189] Standard samples used for calibration curve preparation: TSK standard polyethylene oxide (molecular weight; approximately 900,000, 150,000, 100,000 and 30,000) (manufactured by Tosoh) and polyethylene glycol (molecular weight; approximately 12,000, 4,000 and 1,000) (manufactured by Polymer Laboratory).

[0190] Synthesis of polyamic acid

[0191] <Synthesis example 1>

[0192] DA-1 (2.05 g, 6.0 mmol) and DA-7 (2.80 g, 14.0 mmol), the diamine components, were measured into a 100 mL four-necked flask equipped with a stirrer. NMP (19.4 g) was added and stirred until dissolved. While stirring the diamine solution, DC-1 (4.26 g, 19.0 mmol), the tetracarboxylic dianhydride component, was added, followed by NMP (17.0 g). The mixture was stirred at 60 °C for 15 hours to obtain a solution of polyamic acid (A-1, viscosity: 625 mPa·s, number average molecular weight: 7094).

[0193] <Synthetic Examples 2 to 7>

[0194] The diamine and tetracarboxylic dianhydride components were changed as shown in Table 1 below, and the process was carried out in the same manner as in Synthesis Example 1, thereby obtaining solutions of polyamic acids (A-2) to (A-7) as shown in Table 1 below. The viscosity and molecular weight of the obtained polyamic acids are shown in Table 1 below.

[0195] [Table 1]

[0196]

[0197] [Preparation of Liquid Crystal Alignment Agent]

[0198] <Example 1>

[0199] NMP (6.0 g) and BCS (8.0 g) were added to the polyamic acid (A-1) solution (6.0 g) obtained above, and the mixture was stirred at room temperature for 10 hours to obtain a liquid crystal alignment agent (PAA-1) with a polyamic acid (A-1) concentration of 6% by mass, an NMP concentration of 54% by mass, and a BCS concentration of 40% by mass.

[0200] <Examples 2-3, Comparative Examples 1-3, and Preparation Example 1>

[0201] The polyamic acid solution was changed to the form shown in Table 2 below, and otherwise carried out in the same manner as in Example 1, thereby obtaining the liquid crystal alignment agents (PAA-2) to (PAA-7) shown in Table 2 below.

[0202] [Table 2]

[0203] Example 1 PAA-1 A-1 Polyamic acid (A-1)[6], NMP

[54] , BCS

[40] Example 2 PAA-2 A-2 Polyamic acid (A-2)[6], NMP

[54] , BCS

[40] Example 3 PAA-3 A-3 Polyamic acid (A-3)[6], NMP

[54] , BCS

[40] Comparative Example 1 PAA-4 A-4 Polyamic acid (A-4)[6], NMP

[54] , BCS

[40] Comparative Example 2 PAA-5 A-5 Polyamic acid (A-5)[6], NMP

[54] , BCS

[40] Comparative Example 3 PAA-6 A-6 Polyamic acid (A-6)[6], NMP

[54] , BCS

[40] Preparation Example 1 PAA-7 A-7 Polyamic acid (A-7)[6], NMP

[54] , BCS

[40]

[0204] <Example 4>

[0205] NMP (0.6 g) and BCS (1.4 g) were added to the liquid crystal alignment agent (PAA-1) (4.0 g) obtained above, and the mixture was stirred at room temperature for 10 hours to obtain a liquid crystal alignment agent (PAA-r-1) with a concentration of 4% by mass of polyamic acid (A-1), 46% by mass of NMP, and 50% by mass of BCS.

[0206] <Examples 5-6 and Comparative Examples 4-6>

[0207] The polyamic acid solution was changed to the form shown in Table 3 below, and the same procedure as in Example 4 was followed, thereby obtaining the liquid crystal alignment agents (PAA-r-2) to (PAA-r-6) shown in Table 3 below.

[0208] [Table 3]

[0209] Example 4 PAA-r-1 A-1 Polyamic acid (A-1)[4], NMP

[46] , BCS

[50] Example 5 PAA-r-2 A-2 Polyamic acid (A-2)[4], NMP

[46] , BCS

[50] Example 6 PAA-r-3 A-3 Polyamic acid (A-3)[4], NMP

[46] , BCS

[50] Comparative Example 4 PAA-r-4 A-4 Polyamic acid (A-4)[4], NMP

[46] , BCS

[50] Comparative Example 5 PAA-r-5 A-5 Polyamic acid (A-5)[4], NMP

[46] , BCS

[50] Comparative Example 6 PAA-r-6 A-6 Polyamic acid (A-6)[4], NMP

[46] , BCS

[50]

[0210] <Examples 7-9 and Comparative Examples 7-9>

[0211] The liquid crystal alignment agent (PAA-1) obtained in Example 1 and the liquid crystal alignment agent (PAA-7) obtained in Preparation Example 1 were mixed in a mass ratio of 3:7 (PAA-7:PAA-1) and stirred at room temperature for 3 hours to prepare the liquid crystal alignment agent (PAA-b-1) of Example 7.

[0212] In addition, the combination of liquid crystal alignment agents used was changed as shown in Table 4 below. Otherwise, the same procedure was followed as in Example 7 to prepare the liquid crystal alignment agents (PAA-b-2) to (PAA-b-6) of Examples 8 to 9 and Comparative Examples 7 to 9 shown in Table 4 below.

[0213] [Table 4]

[0214]

[0215] [Solubility of liquid crystal alignment agents in poor solvents]

[0216] The liquid crystal alignment agents prepared in Examples 4-6 and Comparative Examples 4-6 were placed in a freezer at -20°C for 14 hours. Then, they were removed at room temperature, and the precipitation of the polymer solid component was visually confirmed. The results are shown in Table 5. Polymer dissolution is marked as "○", and polymer precipitation is marked as "×".

[0217] [Table 5]

[0218] Example 4 PAA-r-1 ○ Example 5 PAA-r-2 ○ Example 6 PAA-r-3 ○ Comparative Example 4 PAA-r-4 × Comparative Example 5 PAA-r-5 × Comparative Example 6 PAA-r-6 ○

[0219] [Determination of the refractive index of liquid crystal alignment films]

[0220] The liquid crystal alignment agents prepared in Examples 1-3 and Comparative Examples 1-3 were spin-coated onto silicon wafers, dried on a heating plate at 70°C for 90 seconds, and then fired in a hot air circulating oven at 230°C for 20 minutes to form a liquid crystal alignment film with a thickness of 100 nm. Next, a spectroscopic ellipsometry (M-2000, JAWoollam) was used to perform fitting based on the CAUCHY model to measure the refractive index at wavelengths of 250–800 nm. The results are shown in Table 6. Table 6 records the refractive index at a wavelength of 550 nm. A refractive index of 1.630 or higher was designated as "excellent," and a refractive index less than 1.630 was designated as "unacceptable."

[0221] [Table 6]

[0222]

[0223] [Fabrication of liquid crystal alignment film and liquid crystal cell]

[0224] Using the liquid crystal alignment agents prepared in Examples 7-9 and Comparative Examples 7-9 above, liquid crystal cells were fabricated as described below.

[0225] Each liquid crystal alignment agent was spin-coated onto the ITO surface of an ITO electrode substrate having an ITO electrode pattern with pixel size of 100μm × 300μm and line width / space of 5μm. After drying on a heating plate at 70°C for 90 seconds, the substrate was fired in a hot air circulating oven at 230°C for 30 minutes to form a liquid crystal alignment film with a thickness of 100nm.

[0226] In addition, a liquid crystal alignment agent was spin-coated onto the ITO surface without an electrode pattern, dried on a heating plate at 70°C for 90 seconds, and then fired in a hot air circulating oven at 230°C for 20 minutes to form a liquid crystal alignment film with a thickness of 100 nm.

[0227] For the two substrates described above, after dispersing 4μm bead-like spacers on the liquid crystal alignment film of one substrate, a sealant (solvent-based thermosetting epoxy resin) was printed on top of it. Next, the side of the other substrate with the liquid crystal alignment film was used as the inner side and bonded to the previous substrate. The sealant was then thermosetting to create a blank cell. Liquid crystal containing a polymeric compound (MLC-3023, manufactured by MERCK) was injected into this blank cell using a depressurized injection method to create a liquid crystal cell.

[0228] Then, while applying a DC voltage of 15V to the liquid crystal cell, irradiate it with 10J / cm² of light from the outside of the liquid crystal cell. 2Ultraviolet light passed through a filter that cut off wavelengths below 325 nm. It should be noted that the illuminance of the ultraviolet light was measured using an ORC UV-MO3A. Then, to deactivate unreacted polymeric compounds remaining in the liquid crystal cell, the device was irradiated with ultraviolet light (UV lamp: FLR40SUV32 / A-1) for 30 minutes without applied voltage using a UV-FL irradiation device (Toshiba Lighting & Technology).

[0229] [Evaluation of vertical orientation]

[0230] The evaluation of the vertical alignment of each liquid crystal cell fabricated as described above is shown in Table 7. The evaluation method is as follows. With each liquid crystal cell held between polarizers using crossed Nicol lenses and backlighting from the rear, the cells were rotated, and the vertical alignment of the liquid crystals was observed visually by observing changes in brightness. For the evaluation criteria, vertical alignment was marked as "○", and non-vertical alignment was marked as "×". The results are shown in Table 7.

[0231] [Table 7]

[0232] Example 7 PAA-b-1 ○ Example 8 PAA-b-2 ○ Example 9 PAA-b-3 ○ Comparative Example 7 PAA-b-4 ○ Comparative Example 8 PAA-b-5 ○ Comparative Example 9 PAA-b-6 ○

Claims

1. A liquid crystal alignment agent, characterized in that, Contains a polymer (P), said polymer (P) comprising at least one selected from the group consisting of a polyimide precursor obtained by using a diamine component comprising a diamine (1) as shown in formula (1) below, and a polyimide. In the formula, Ar represents phenylene, Q represents a divalent organic group with 10 to 40 carbon atoms as shown in formula (f) below, Q is bonded to two oxygen atoms respectively on the benzene ring constituting the at least one naphthalene ring, and the benzene ring bonded to one oxygen atom is different from the benzene ring bonded to the other oxygen atom; any hydrogen atom on the phenylene is optionally substituted with at least one selected from the group consisting of an alkyl group with 1 to 3 carbon atoms, an alkoxy group with 1 to 3 carbon atoms, a fluorinated alkyl group with 1 to 3 carbon atoms, a fluorinated alkoxy group with 1 to 3 carbon atoms, and a fluorine atom. In the formula, A1 and A2 are naphthalene rings that are optionally substituents; X1 and X2 are single bonds, oxygen atoms, or sulfur atoms, respectively; Y is an alkylene group with 1 to 8 carbon atoms, or a divalent organic group containing oxygen or sulfur atoms between carbon-carbon bonds of an alkylene group with 1 to 8 carbon atoms; m is an integer from 0 to 2, and n is an integer 1; * indicates a bond.

2. The liquid crystal alignment agent according to claim 1, wherein, The diamine (1) is a diamine represented by the following formula (d-2). 。 3. The liquid crystal alignment agent according to claim 1 or 2, wherein, The polymer (P) comprises a diamine (s) as a constituent component, said diamine (s) having at least one of the following groups of partial structures selected from those shown in formulas (S1) to (S3). In formula (S1), X 1 and X 2 Each can be used independently to represent a single bond and -(CH2). a -, -CONH-, -NHCO-, -CON(CH3)-, -N(CH3)CO-, -NH-, -O-, -COO-, -OCO-, -((CH2) a1 -A1) m1 - or - (A1-(CH2)) a1 ) m1 -, the - (CH2) a In the given information, a is an integer from 1 to 15, and the term - ((CH2)) a1 -A1) m1 - and - (A1-(CH2)) a1 ) m1 In the given text, a1 is an integer from 1 to 15, A1 represents an oxygen atom, -COO-, or -OCO-, and m1 is an integer from 1 to 2; when m1 is 2, multiple a1s are independent, and multiple A1s are independent; G 1 and G 2 Each of the following independently represents a divalent cyclic group selected from divalent aromatic groups having 6 to 12 carbon atoms and divalent alicyclic groups having 3 to 8 carbon atoms; any hydrogen atom on the cyclic group is optionally substituted with at least one of the following groups: alkyl group having 1 to 3 carbon atoms, alkoxy group having 1 to 3 carbon atoms, fluorinated alkyl group having 1 to 3 carbon atoms, fluorinated alkoxy group having 1 to 3 carbon atoms, and fluorine atom; m and n are each independently integers from 0 to 3, and the sum of m and n is 1 to 6; R 1 Representing 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 may be optionally replaced by a fluorine atom. In formula (S2), X 3 Represents single bonds, -CONH-, -NHCO-, -CON(CH3)-, -N(CH3)CO-, -NH-, -O-, -CH2O-, -COO-, or -OCO-; R 2 Representing 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 may be optionally replaced by a fluorine atom. In formula (S3), X 4 This represents -CONH-, -NHCO-, -O-, -COO-, -OCO-, and -((CH2)). a1 -A1) m1 - or - (A1-(CH2)) a1 ) m1 - where a1 is an integer from 1 to 15, A1 represents an oxygen atom, -COO-, or -OCO-, and m1 is an integer from 1 to 2; when m1 is 2, the multiple a1s are independent, and the multiple A1s are independent; R 3 This indicates a structure with a steroidal framework.

4. The liquid crystal alignment agent according to claim 3, wherein, The diamine (s) is a diamine represented by formula (d1) or formula (d2) below. In the formula, X represents a single bond, -O-, -C(CH3)2-, -NH-, -CO-, -COO-, -CONH-, or -(CH2). m -, -SO2-, -O- (CH2) m -O-, -O-C(CH3)2-, -CO-(CH2) m -、-CO-(CH2) m -CO-, -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-; m is an integer from 1 to 8; Y independently represents a portion of the structure of any of the expressions (S1) to (S3).

5. The liquid crystal alignment agent according to claim 4, wherein, The diamine represented by formula (d1) is any diamine selected from the group consisting of formulas (d1-1) to (d1-18) below. In the formula, n is an integer from 1 to 20. 。 6. The liquid crystal alignment agent according to claim 4, wherein, The diamine represented by formula (d2) is any diamine selected from the group consisting of formulas (d2-1) to (d2-6) below. In the formula, X p1 ~X p8 It represents - (CH2) a -, -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2O-, -CH2OCO-, -COO- or -OCO-, wherein -(CH2)- a In the equation, a is an integer from 1 to 15; X s1 ~X s4 Each can be represented independently as -O-, -COO-, or -OCO-; X a ~X f It represents a single bond, -O-, -NH-, or -O- (CH2). m -O-, the -O-(CH2) m In -O-, m is an integer from 1 to 8; R 1a ~R 1h Each can be independently represented as 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.

7. The liquid crystal alignment agent according to claim 1 or 2, wherein, The polymer (P) comprises a tetracarboxylic acid component containing a tetracarboxylic acid dianhydride as shown in the following formula (T) as a constituent component. In equation (T), X represents a structure selected from (x-1) to (x-13) below. In (x-1)~(x-13), R 1 ~R 4 Each of the following can independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, an alkynyl group with 2 to 6 carbon atoms, a monovalent organic group containing a fluorine atom with 1 to 6 carbon atoms, or a phenyl group; R 5 and R 6 Each of the following groups independently represents a hydrogen atom or a methyl group; j and k are integers 0 or 1; A1 and A2 independently represent a single bond, an ether bond -O-, a carbonyl bond -CO-, an ester bond -COO- or -OCO-, a phenylene bond, a sulfonyl bond -SO2-, or an amide bond -CONH- or -NHCO-; *1 is a bond bonded to the anhydride group of one party, and *2 is a bond bonded to the anhydride group of the other party; in the formula (x-13), the two A2 groups are optionally the same or different from each other.

8. The liquid crystal alignment agent according to claim 7, wherein, In the given formula (T), X is any one of (x-1) to (x-7) and (x-11) to (x-13).

9. The liquid crystal alignment agent according to claim 1 or 2, wherein, The polymer (P) contains 1 to 100 mol% of the diamine (1) in its entire diamine component.

10. The liquid crystal alignment agent according to claim 3, wherein, The polymer (P) contains 1 to 99 mol% of the diamine (s) in its total diamine composition.

11. A liquid crystal alignment film formed using a liquid crystal alignment agent as described in any one of claims 1 to 10.

12. The liquid crystal alignment film according to claim 11, wherein, The liquid crystal alignment film is for vertical alignment.

13. A liquid crystal display element comprising a liquid crystal alignment film as described in claim 11 or 12.

14. A method for manufacturing a liquid crystal display element, comprising the following steps (A), (B) and (C). Step (A): A step of coating a liquid crystal alignment agent as described in any one of claims 1 to 10 onto a pair of substrates having a conductive film to form a coating film; Step (B): A step of forming a liquid crystal cell by arranging the coating layers opposite each other with liquid crystal molecules separated by layers; and Step (C): A step of irradiating the liquid crystal cell with light while applying a voltage between the conductive films of the pair of substrates.

Images