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

Abstract

The present application relates to a liquid crystal alignment agent which satisfies at least one selected from the group consisting of (I) and (II). (I): contains a polymer (A) having a repeating unit selected from the group consisting of a repeating unit represented by the following formula (1-a) and a repeating unit represented by the following formula (1-i), and an epoxy compound (B) represented by the following formula (2). (II): contains a reaction product of the polymer (A) and the epoxy compound (B).

Description

Technical Field

[0001] This invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element. Background Technology

[0002] Liquid crystal display (LCD) elements are widely used in the display components of personal computers, mobile phones, smartphones, televisions, etc. An LCD element typically includes: a liquid crystal layer sandwiched between an element substrate and a color filter substrate; pixel electrodes and a common electrode that apply an electric field to the liquid crystal layer; an alignment film that controls the orientation of the liquid crystal molecules in the liquid crystal layer; a thin-film transistor (TFT) that switches the electrical signals supplied to the pixel electrodes; and so on. Known driving methods for liquid crystal molecules include vertical electric field methods such as TN (Twisted Nematic) and VA (Vertical Alignment); and lateral electric field methods such as IPS (In-Plane Switching) and FFS (Fringe Field Switching). In lateral electric field methods where electrodes are formed only on one side of the substrate and an electric field is applied in a direction parallel to the substrate, LCD elements are known to have a wider viewing angle and can achieve higher quality displays compared to conventional vertical electric field methods that apply voltage to electrodes formed on both upper and lower substrates to drive the liquid crystal.

[0003] For liquid crystal cells using a lateral electric field, if the alignment stability of the liquid crystal is low, the liquid crystal cannot return to its initial state after prolonged driving, leading to reduced contrast and image retention. Therefore, the stability of liquid crystal alignment is crucial. Furthermore, static electricity easily accumulates within the liquid crystal cell. Due to the application of asymmetrical positive and negative voltages generated during driving, charges accumulate within the cell. These accumulated charges affect the display in the form of liquid crystal alignment disorder and image retention, significantly reducing the display quality of the liquid crystal element. Moreover, because backlight illumination on the liquid crystal cell immediately after driving causes charge accumulation, image retention occurs even with short-term driving. In addition, flickering (flickering) and other problems also occur during driving.

[0004] As a liquid crystal alignment agent to reduce charge accumulation, Patent Document 1 discloses a liquid crystal alignment agent containing a polymer obtained by polycondensation of a specific diamine with an aliphatic tetracarboxylic acid derivative.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2004 / 021076 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The inventors conducted research and found that when diamines with intramolecular nitrogen-containing structures, represented by the aforementioned specific diamines, are used as raw material components of polymers, although the rate of charge accumulation is accelerated, the absolute value of the charge increases. Especially in recent high-brightness liquid crystal display elements, the backlight brightness is increasing, and the visual certainty of afterimages caused by accumulated charge is also increasing. Therefore, there is a need for liquid crystal alignment films that can reduce the absolute value of accumulated charge and reduce the generated charge in a short time. Furthermore, there is a greater need than ever before for liquid crystal alignment films that reduce charge accumulation and flicker caused by backlight.

[0010] The object of the present invention is to provide a liquid crystal alignment agent that can reduce the absolute value of accumulated charge and reduce the generated charge in a short time; and a liquid crystal alignment film that reduces charge accumulation and flicker caused by backlight.

[0011] Solution for solving the problem

[0012] To achieve the above objectives, the inventors conducted various studies and found that reducing the carboxyl and imide ring structures in the liquid crystal alignment film is effective in achieving these objectives. Furthermore, they discovered that a liquid crystal alignment agent based on the following configuration is optimal for achieving these objectives, thus completing this invention.

[0013] Therefore, based on the above insights, the present invention has the following main points.

[0014] One aspect of the present invention is a liquid crystal alignment agent that satisfies at least one selected from the group consisting of (I) and (II) below.

[0015] (I): Contains a polymer (A) and an epoxy compound (B) as shown in formula (2) below, wherein the polymer (A) has repeating units selected from the group consisting of repeating units shown in formula (1-a) below and repeating units shown in formula (1-i) below.

[0016] (II): The reaction product containing the polymer (A) and the epoxy compound (B) (hereinafter also referred to as "modified polymer (2mp)").

[0017]

[0018] (In formulas (1-a) and (1-i), X1 represents a tetravalent organic group. Y1 represents a divalent organic group. Each of the two R1 and Z1 independently represents a monovalent organic group formed by replacing at least one hydrogen 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 tert-butoxycarbonyl group, a 9-fluorenylmethoxycarbonyl group, an alkylsilyl group with 1 to 6 carbon atoms, or a hydrogen atom of the alkyl, alkenyl, or alkynyl group with a halogen atom or a nitro group. R1 and Z1 may optionally be the same or different.)

[0019]

[0020] (In formula (2), R1 to R4 each independently represent a hydrogen atom, hydroxyl group, halogen atom, nitro group, cyano group, alkyl group with 1 to 5 carbon atoms, alkenyl group with 2 to 5 carbon atoms, alkynyl group with 2 to 5 carbon atoms, or a monovalent organic group formed by replacing at least one of the hydrogen atoms of the alkyl group, alkenyl group, or alkynyl group with a hydroxyl group, halogen atom, nitro group, or cyano group. At least one of R1 to R4 represents a group other than a hydrogen atom.)

[0021] Another aspect of the present invention is a liquid crystal alignment agent that satisfies at least one selected from the group consisting of (I') and (II') and (III').

[0022] (I'): Contains a polymer (A') and an epoxy compound (B') as shown in formula (2'), wherein the polymer (A') has repeating units selected from the group consisting of repeating units shown in formula (1'-a) and repeating units shown in formula (1'-i).

[0023] (II'): The reaction product containing the polymer (A') and the epoxy compound (B') (hereinafter also referred to as "modified polymer (2mp')").

[0024] (III'): The amount of the epoxy compound represented by formula (2') is 0.1 to 50 parts by mass relative to a total of 100 parts by mass of the polymer (A') and other polymers besides the polymer (A').

[0025]

[0026] In equations (1'-a) and (1'-i), X 1’ Y represents a tetravalent organic group. 1’ This indicates that the following formula (d) is used to select the option. Y’ -1) shows a partial structure, and the following formula (d) Y’-2) represents a partial structure and at least one divalent organic group from the group consisting of a nitrogen-containing heterocycle and the partial structure shown. Two R 1’ and Z 1’ Each of the following independently represents a monovalent organic group formed by replacing at least one of the hydrogen atoms in a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a tert-butoxycarbonyl group, a 9-fluorenylmethoxycarbonyl group, an alkylsilyl group having 1 to 6 carbon atoms, or a halogen atom or a nitro group. 1’ and Z 1’ (Optional: same or different)

[0027]

[0028] (Formula (d) Y’ In formula (d), R represents a hydrogen atom or a monovalent organic group. Y’ -1)~(d Y’ In (-2), any hydrogen atom on the benzene ring is optionally substituted with a monovalent substituent. * indicates a bond.

[0029]

[0030] (In equation (2'), R) o The term "(q)" refers to a monovalent organic group (q) consisting of an alkyl group (1-5 carbon atoms), an alkenyl group (2-5 carbon atoms), an alkynyl group (2-5 carbon atoms), a phenyl group, a monovalent organic group (q) formed by introducing an -O- group between carbon-carbon bonds in the alkyl group, or a monovalent organic group (q) formed by substituting at least one hydrogen atom of the alkyl group, alkenyl group, alkynyl group, phenyl group, or monovalent organic group (q) with a hydroxyl group, a halogen atom, a nitro group, or a cyano group.

[0031] It should be noted that, in this specification as a whole, the following can be listed as halogen atoms: fluorine atom, chlorine atom, bromine atom, iodine atom, etc., and * indicates a bond.

[0032] Invention Effects

[0033] By using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film that can reduce the absolute value of accumulated charge and reduce the generated charge in a short time can be obtained; as well as a liquid crystal alignment film that reduces charge accumulation and flicker caused by backlight. Attached Figure Description

[0034] Figure 1 This is a schematic cross-sectional view illustrating an example of a transverse electric field liquid crystal display element of the present invention.

[0035] Figure 2 This is a schematic cross-sectional view showing another example of the transverse electric field liquid crystal display element of the present invention. Detailed Implementation

[0036] <Polymer (A)>

[0037] Polymer (A) is a polymer having repeating units selected from the group consisting of repeating units shown in formula (1-a) and repeating units shown in formula (1-i).

[0038] <The repeating unit shown in equation (1-a)>

[0039] In formula (1-a) above, X1 represents a tetravalent organic group. Examples of such a tetravalent organic group include: a tetravalent organic group derived from aliphatic tetracarboxylic dianhydride or its derivatives; a tetravalent organic group derived from alicyclic tetracarboxylic dianhydride or its derivatives; or a tetravalent organic group derived from aromatic tetracarboxylic dianhydride or its derivatives. Examples of derivatives of tetracarboxylic dianhydride include: tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters, and tetracarboxylic acid dialkyl ester dihalides.

[0040] Here, the aromatic tetracarboxylic acid dianhydride is obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to the aromatic ring.

[0041] Aliphatic tetracarboxylic dianhydrides are obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. The structure need not consist solely of a chain hydrocarbon; it can also have alicyclic or aromatic ring structures in some parts.

[0042] Furthermore, alicyclic tetracarboxylic dianhydrides are 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.

[0043] The X1 mentioned above is preferably a tetravalent organic group derived from the tetracarboxylic acid dianhydride or its derivatives shown in the following formula (t).

[0044]

[0045] In formula (t), X T The structure is selected from the following formulas (X1-1) to (X1-25). * indicates a bond.

[0046]

[0047]

[0048] In equations (X1-1)~(X1-4), R1~R 21Each of these groups independently represents 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. From the perspective of liquid crystal orientation, R1 to R2... 21 Preferably, hydrogen atoms, halogen atoms, methyl or ethyl groups are used, and more preferably hydrogen atoms or methyl groups are used.

[0049] In formulas (X1-24) to (X1-25), j and k are integers of 0 or 1, and A1 and A2 independently represent single bonds, -O-, -CO-, -COO-, phenylene, sulfonyl, or amide groups. Multiple A2 groups may optionally be the same or different.

[0050] As a specific example of formula (X1-1), formulas (1-1) to (1-6) can be listed below. From the viewpoint of improving liquid crystal alignment, (1-1) is particularly preferred. *The meaning is the same as above*.

[0051]

[0052] As preferred examples of the above formulas (X1-24) and (X1-25), the following formulas (X1-26) to (X1-41) can be listed. *The meaning is the same as above*.

[0053]

[0054] From the perspective of improving liquid crystal alignment, the above X T Preferably, the above formulas (X1-1) to (X1-10), (X1-18) to (X1-23), or (X1-24) to (X1-25) are preferred, more preferably the above formulas (X1-1), (X1-5), (X1-7) to (X1-10), (X1-21), (X1-23), or (X1-24) to (X1-25) are preferred, and even more preferably the above formulas (1-1), (1-2), (X1-5), (X1-7), (X1-8), (X1-9), or (X1-26) to (X1-30) are preferred.

[0055] Formula (1-a) can also be a tetravalent organic group derived from a tetracarboxylic dianhydride or its derivative other than the above formula (t).

[0056] In the above formula (1-a), Y1 represents a divalent organic group. Specific examples of divalent organic groups of Y1 include divalent organic groups formed by removing two amino groups from diamines.

[0057] Diamines represented by the following formula (O); diamines having photo-oriented groups such as 4,4'-diaminoazobenzene or diaminodiphenylacetylene; diamines having amide or urea bonds such as the following formulas (h-1) to (h-8); 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, and the following formula (d oThe diamine shown in the figure; a diamine having at least one nitrogen-containing structure (hereinafter also referred to as a nitrogen-containing structure) selected from the group consisting of heterocycles, secondary amino groups, and tertiary amino groups containing a nitrogen atom (wherein, the molecule does not have an amino group bonded to a protecting group that is removed by heating and replaced with a hydrogen atom); 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol; 4,4'-diamino-3,3'-dihydroxybiphenyl, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzyl alcohol Acids and diamines having carboxyl groups, such as those shown in formulas (3b-1) to (3b-4); 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indane-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indane-6-amine; diamines having photopolymerizable groups at the ends, such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallyl aniline; cholesteryloxy-3,5-diaminobenzene, Diamines having a steroidal skeleton, such as cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanostane 3,5-diaminobenzoate, and 3,6-bis(4-aminobenzoyloxy)cholestan; diamines shown in formulas (V-1) to (V-6) below; diamines having the group "-N(D)-" (D represents a protecting group that is removed by heating and replaced with a hydrogen atom, preferably tert-butoxycarbonyl) such as formulas (5-1) to (5-11) below; 1,3-bis( Diamines having a siloxane bond, such as 3-aminopropyl)-tetramethyldisiloxane and diamines represented by the following formula (Ds-1); diamines having an oxazoline structure, such as those represented by the following formulas (Ox-1) to (Ox-2); m-phenylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and diamines formed by bonding two amino groups to any group represented by any of the formulas (Y-1) to (Y-167) as described in International Publication No. 2018 / 117239.

[0058]

[0059] In formula (O), Ar represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring. The two Ars may be identical or different, and any hydrogen atom on the aforementioned ring in Ar may be substituted with a monovalent substituent. p is an integer of 0 or 1. Q2 represents -(CH2). n -(n is an integer from 2 to 18), or -(CH2)n A group formed by replacing at least a portion of -CH2- with any one of -O-, -C(=O)-, and -O-C(=O)-.

[0060] Examples of monovalent substituents include: halogen atoms, hydroxyl groups, alkyl groups with 1 to 6 carbon atoms, alkenyl groups with 2 to 6 carbon atoms, alkoxy groups with 1 to 6 carbon atoms, fluoroalkyl groups with 1 to 6 carbon atoms, fluoroalkenyl groups with 2 to 6 carbon atoms, fluoroalkoxy groups with 1 to 6 carbon atoms, carboxyl groups, alkoxycarbonyl groups with 2 to 6 carbon atoms, cyano groups, nitro groups, etc.

[0061]

[0062] (Formula (d) O In the case of multiple m, each m can be arbitrarily identical or different.

[0063]

[0064] (In equation (3b-1), A) 1 The values ​​represent single bonds, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CO-N(CH3)-, or -N(CH3)-CO-. m1 and m2 are each independent integers from 0 to 4, and m1+m2 is an integer from 1 to 4.

[0065] In equation (3b-2), m3 and m4 are each an independent integer from 1 to 5.

[0066] In equation (3b-3), A 2 It represents a straight-chain or branched alkyl group with 1 to 5 carbon atoms, where m5 is an integer from 1 to 5.

[0067] In equation (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-, -CO-N(CH3)-, or -N(CH3)-CO-, where m6 is an integer from 1 to 4.

[0068]

[0069] (In formulas (V-1)~(V-6), X) v1~X v4 and X p1 ~X p2 Each can be represented independently as -(CH2) a - (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CH2O-, -CH2-OCO-, -COO- or -OCO-, X v5 This represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. X a Represents single bonds, -O-, -NH-, -O-(CH2). m -O- (m represents an integer from 1 to 6), -C(CH3)2-, -CO-, -(CH2) m - (m represents an integer from 1 to 6), -SO2-, -O-C(CH3)2-, -CO-(CH2) m -(m represents an integer from 1 to 6), -NH-(CH2) m -(m represents an integer from 1 to 6), -SO2-(CH2) m -(m represents an integer from 1 to 6), -CONH-(CH2) m -(m represents an integer from 1 to 6), -CONH-(CH2) m -NHCO- (m represents an integer from 1 to 6), -COO- (CH2) m -OCO- (m represents an integer from 1 to 6), -CONH-, -NH- (CH2) m -NH- (m represents an integer from 1 to 6) or -SO2-(CH2) m -SO2- (m represents an integer from 1 to 6), R v1 ~R v4 and R 1a ~R 1b Each of the two k's 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. The two k's may optionally be the same or different.

[0070]

[0071] (Boc represents tert-butoxycarbonyl.)

[0072]

[0073] As the above formula (d) o From the viewpoint of improving liquid crystal alignment, the diamine shown in the following formula (d) is preferred. o -1)~(d oThe diamines, 3,3'-diaminodiphenyl ethers, 3,4'-diaminodiphenyl ethers, and 4,4'-diaminodiphenyl ethers shown in (-6)

[0074]

[0075] In the diamine represented by formula (O) above, any hydrogen atom of the benzene ring, biphenyl structure, or naphthalene ring may optionally be substituted with a monovalent substituent. Examples of substituents for the above ring include: halogen atoms, alkyl groups having 1 to 10 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, alkoxy groups having 1 to 10 carbon atoms, fluoroalkyl groups having 1 to 10 carbon atoms, fluoroalkenyl groups having 2 to 10 carbon atoms, fluoroalkoxy groups having 1 to 10 carbon atoms, alkoxycarbonyl groups having 1 to 10 carbon atoms, cyano groups, nitro groups, etc.

[0076] From the viewpoint of improving liquid crystal orientation, the diamine represented by the above formula (O) is preferably any of the following formulas (o-1) to (o-16) as the diamine.

[0077]

[0078] Examples of nitrogen-containing heterocycles that can be present in diamines with the aforementioned nitrogen-containing structure include: pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, isoquinoline, naphthidine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, and hexamethyleneimine. Pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, or acridine are preferred.

[0079] The diamines with nitrogen-containing structures described above may have secondary and tertiary amino groups, for example, represented by the following formula (n).

[0080]

[0081] In the above formula (n), R represents a hydrogen atom or a monovalent hydrocarbon group with 1 to 10 carbon atoms. "*" represents a bond bonded to a hydrocarbon group, at least one of which is bonded to an aromatic hydrocarbon group.

[0082] Examples of monovalent hydrocarbon groups that can be represented by R in formula (n) above include: alkyl groups such as methyl, ethyl, and propyl; cycloalkyl groups such as cyclohexyl; and aryl groups such as phenyl and methylphenyl. R is preferably a hydrogen atom or a methyl group.

[0083] Specific examples of diamines having a nitrogen-containing structure include: 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, diamines represented by formulas (Dp-1) to (Dp-8) below, and diamines represented by formulas (z-1) to (z-13) below.

[0084]

[0085]

[0086] From the viewpoint of improving liquid crystal orientation, Y1 can be a divalent organic group obtained by removing two amino groups from a diamine, wherein the diamine is selected from the diamine shown in the above formula (O), a diamine having an amide bond or a urea bond, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, and the above formula (d o The group consisting of diamines shown in the figure, 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, and diamines having the group "-N(D)-" (D represents a protecting group that is removed by heating and replaced with a hydrogen atom, preferably tert-butoxycarbonyl).

[0087] From the viewpoint of reducing the absolute value of accumulated charge and reducing the generated charge in a short period of time, Y1 in formula (1-a) can be a divalent organic group formed by removing two amino groups from the following diamines, wherein the diamine is selected from the group consisting of diamines having a nitrogen-containing structure, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, and diamines having a carboxyl group.

[0088] In formula (1-a) above, specific examples of alkyl groups having 1 to 6 carbon atoms in R1 and Z1 include: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, cyclopentyl, hexyl, and cyclohexyl. Specific examples of alkenyl groups having 2 to 6 carbon atoms in R1 and Z1 include: vinyl, allyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, isobutenyl, 1,3-butadienyl, 2-pentenyl, hexenyl, and cyclohexenyl. Specific examples of alkynyl groups having 2 to 6 carbon atoms in R1 and Z1 include: ethynyl, 1-propynyl, and 2-propynyl. Examples of alkylsilyl groups with 1 to 6 carbon atoms in R1 and Z1 include: trimethylsilyl, triethylsilyl, dimethylethylsilyl, isopropyl dimethylsilyl, and tert-butyl dimethylsilyl.

[0089] From the viewpoint of achieving the effects of the present invention, R1 and Z1 are each independently preferred to be hydrogen atoms or alkyl groups having 1 to 3 carbon atoms, more preferably hydrogen atoms or methyl groups. R1 and Z1 are each optionally one or more of the same.

[0090] <The repeating unit shown in equation (1-i)>

[0091] In the above formula (1-i), X1 represents a tetravalent organic group and Y1 represents a divalent organic group. Specific examples and preferred embodiments of X1 and Y1 are the same as those of X1 and Y1 in the above formula (1-a).

[0092] <Polymer (A')>

[0093] Polymer (A') is a polymer having repeating units selected from the group consisting of repeating units shown in formula (1'-a) and repeating units shown in formula (1'-i).

[0094] <The repeating unit shown in equation (1'-a)>

[0095] In the above equation (1'-a), X 1’ This represents a tetravalent organic group. As a specific example of such a tetravalent organic group, the tetravalent organic group illustrated in X1 of the above formula (1'-a) can be listed.

[0096] In the above equation (1'-a), Y 1’ This indicates that the following formula (d) is used to select the option. Y’ -1) shows a partial structure, and the following formula (d) Y’ -2) is a divalent organic group consisting of at least one partial structure of the group consisting of the partial structure shown and the nitrogen-containing heterocycle.

[0097]

[0098] (Formula (d) Y’ In formula (d), R represents a hydrogen atom or a monovalent organic group. Y’ -1)~(d Y’ In (-2), any hydrogen atom on the benzene ring is optionally substituted with a monovalent substituent. * indicates a bond.

[0099] As the above formula (d) Y’ -1)~(d Y’ The monovalent substituents of the benzene ring in -2) can be, for example, halogen atoms, hydroxyl groups, alkyl groups with 1 to 6 carbon atoms, alkenyl groups with 2 to 6 carbon atoms, alkoxy groups with 1 to 6 carbon atoms, fluoroalkyl groups with 1 to 6 carbon atoms, fluoroalkenyl groups with 2 to 6 carbon atoms, fluoroalkoxy groups with 1 to 6 carbon atoms, carboxyl groups, alkoxycarbonyl groups with 2 to 6 carbon atoms, cyano groups, nitro groups, etc.

[0100] As the above formula (d) Y’ The monovalent organic groups of R in -1) can be listed as: monovalent hydrocarbon groups with 1 to 10 carbon atoms; monovalent groups formed by introducing functional groups such as -O-, -COO-, -CO-, -NHCO-, -S-, and -NH- between the carbon-carbon bonds in the hydrocarbon group; monovalent aromatic heterocyclic groups; and protecting groups of amino groups. The above formula (d) Y’ In -1), the monovalent organic group of R is preferably a monovalent hydrocarbon group with 1 to 10 carbon atoms, more preferably an alkyl group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, an alkynyl group with 2 to 5 carbon atoms, or a phenyl group.

[0101] In the above formula (1'-a), Y 1’ The polymer (A') has at least any two directions selected from the above formula (d) in the main chain direction and side chain direction. Y’ -1) shows a partial structure, (d Y’ -2) shows a partial structure and at least one partial structure from the group consisting of nitrogen-containing heterocycles. Furthermore, Y 1’ It may also have one, two, or three or more of the above-mentioned structural components. Preferably, Y... 1’ Preferably, the above-mentioned partial structure is present in the main chain direction of the polymer (A').

[0102] As a specific example of the nitrogen-containing heterocycles mentioned above, the nitrogen-containing heterocycles illustrated in the diamines having nitrogen-containing structures described above can be listed.

[0103] Y 1’ Preferably, it is a divalent organic group formed by removing two amino groups from a diamine having a nitrogen-containing structure, as exemplified in the polymer (A) above, or a group of the above formula (d) Y’ -2) shows a divalent organic group. Having the above formula (dY’ -2) The divalent organic group shown is Y 1’ The polymer (A') can be obtained, for example, by using a diamine, which has amino groups bonded to its respective bonding bonds, as a raw material for the polymer (A').

[0104] As the above formula (d) Y’ A more preferred structure of the divalent organic group shown in -2) can be listed as follows (2d) Y’ -1)~(2d Y’ -3) shows the divalent organic group.

[0105]

[0106] (Any hydrogen atom on the benzene ring may be optionally replaced by a monovalent substituent. * indicates a bond.)

[0107] As the above equation (2d) Y’ -1)~(2d Y’ Specific examples of monovalent substituents in -3) can be listed in the above formula (d) Y’ -1)~(d Y’ The structure is illustrated by the monovalent substituent in -2).

[0108] In the above equation (1'-a), as R 1’ and Z 1’ Specific examples of alkyl groups having 1 to 6 carbon atoms include: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, cyclopentyl, hexyl, and cyclohexyl. As R 1’ and Z 1’ Specific examples of alkenyl groups with 2 to 6 carbon atoms include: vinyl, allyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, isobutenyl, 1,3-butadienyl, 2-pentenyl, hexenyl, cyclohexenyl, etc. As R 1’ and Z 1’ Specific examples of alkynyl groups with 2 to 6 carbon atoms include: ethynyl, 1-propynyl, 2-propynyl, etc. As R 1’ and Z 1’ Alkyl silyl groups with 1 to 6 carbon atoms include: trimethylsilyl, triethylsilyl, dimethylethylsilyl, isopropyl dimethylsilyl, and tert-butyl dimethylsilyl.

[0109] From the viewpoint of achieving the effects of the present invention, R 1’ and Z 1’ Each is independently preferred to have a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group. 1’ and Z1’ Each may choose one or more of the following.

[0110] <Repeating unit shown in equation (1'-i)>

[0111] In the above equation (1'-i), X 1’ Y represents a tetravalent organic group. 1’ This indicates a divalent organic group. X 1’ and Y 1’ Specific examples, preferred solutions, and X in the above formula (1'-a) 1’ and Y 1’ same.

[0112] <Compound (B) shown in formula (2)>

[0113] The epoxy compound (B) shown in formula (2) is the compound shown in formula (2) above. By using the epoxy compound with a specific structure shown in formula (2) in combination with the polymer (A), or as a raw material for modifying the polymer (2mp), the resulting liquid crystal alignment film can be endowed with the function of reducing the absolute value of accumulated charge and reducing the generated charge in a short time. In addition, the liquid crystal alignment film is endowed with the function of reducing charge accumulation and flicker caused by backlight. Moreover, the epoxy compound shown in formula (2) of the present invention has the special effect of suppressing the change in pretilt angle of liquid crystal and the decrease in voltage retention rate caused by addition.

[0114] Specific examples of alkyl groups with 1 to 5 carbon atoms in R1 to R4 of the above formula (2) include: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, cyclopentyl, etc.

[0115] Specific examples of alkenyl groups with 2 to 5 carbon atoms in R1 to R4 of the above formula (2) include: vinyl, allyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, isobutenyl, 1,3-butadienyl, 2-pentenyl, etc.

[0116] Specific examples of alkynyl groups with 2 to 5 carbon atoms in R1 to R4 of the above formula (2) include: ethynyl, 1-propynyl, 2-propynyl, etc.

[0117] As preferred specific examples of the epoxy compounds shown in formula (2) above, compounds shown in formulas (e2-1) to (e2-25) below can be listed, but are not limited thereto. The above epoxy compounds can be used alone or in combination of two or more.

[0118]

[0119] <Compound (B') shown in formula (2')>

[0120] The epoxy compound (B') shown in formula (2') is the compound shown in formula (2') above. By using the epoxy compound with a specific structure shown in formula (2') in combination with the polymer (A'), or as a raw material for the modified polymer (2mp'), the resulting liquid crystal alignment film can be endowed with the function of reducing the absolute value of accumulated charge and reducing the generated charge in a short time. In addition, the liquid crystal alignment film is endowed with the function of reducing charge accumulation and flicker caused by backlight. Moreover, the epoxy compound shown in formula (2') of the present invention has the special effect of suppressing the change in pretilt angle of liquid crystal and the decrease in voltage retention rate caused by addition.

[0121] As specific examples of alkyl groups with 1 to 5 carbon atoms in R0 of the above formula (2'), the structures shown in R1 to R4 of the above formula (2) can be listed.

[0122] As specific examples of alkenyl groups with 2 to 5 carbon atoms in R0 of the above formula (2'), the structures illustrated in R1 to R4 of the above formula (2) can be listed.

[0123] As specific examples of alkynyl groups with 2 to 5 carbon atoms in R0 of the above formula (2'), the structures shown in R1 to R4 of the above formula (2) can be listed.

[0124] Preferred examples of the epoxy compounds shown in formula (2') above include compounds shown in formulas (e2'-1) to (e2'-11) below, but are not limited thereto. The above epoxy compounds can be used alone or in combination of two or more.

[0125]

[0126] One embodiment of the liquid crystal alignment agent of the present invention satisfies at least one selected from the group consisting of (I) and (II) below.

[0127] (I): Contains polymer (A) and epoxy compound (B) as shown in formula (2).

[0128] (II): Contains the reaction product of polymer (A) and epoxy compound (B) [modified polymer (2mp)].

[0129] Furthermore, in the liquid crystal alignment agent, the amount of the epoxy compound shown in formula (2) is not particularly limited, and is preferably 0.1 to 50 parts by mass relative to a total of 100 parts by mass of polymer (A) and other polymers other than polymer (A), more preferably 1 to 30 parts by mass, and even more preferably 5 to 30 parts by mass.

[0130] Here, "the amount of epoxy compound shown in formula (2)" refers to the total amount of epoxy compound shown in formula (2) in the liquid crystal alignment agent and the total amount of epoxy compound shown in formula (2) constituting the modified polymer (2mp).

[0131] In addition, the polymer (A) in “total of 100 parts by mass of polymer (A) and other polymers besides polymer (A)” refers to polymer (A) in the liquid crystal alignment agent and polymer (A) constituting the modified polymer (2mp).

[0132] Therefore, for example, in the case where the liquid crystal alignment agent contains only 100 parts by mass of polymer (A), 10 parts by mass of epoxy compound (B), and 2000 parts by mass of solvent, the amount of epoxy compound represented by formula (2) in the liquid crystal alignment agent is 10 parts by mass relative to the total of 100 parts by mass of polymer (A) and other polymers besides polymer (B).

[0133] Furthermore, for example, in the case where the liquid crystal alignment agent contains only 120 parts by mass of modified polymer (2mp), 100 parts by mass of other polymers (excluding polymer (A) and modified polymer (2mp)), and 4000 parts by mass of solvent, and the modified polymer (2mp) is the reaction product of 100 parts by mass of polymer (A) and 20 parts by mass of epoxy compound (B), the amount of epoxy compound represented by formula (2) in the liquid crystal alignment agent is 10 parts by mass relative to the total of 100 parts by mass of polymer (A) and other polymers besides polymer (B).

[0134] One embodiment of the liquid crystal alignment agent of the present invention satisfies at least one selected from the group consisting of (I') and (II') below and (III' below).

[0135] (I'): Contains polymer (A') and epoxy compound (B') as shown in formula (2').

[0136] (II'): Contains the reaction product of polymer (A') and epoxy compound (B') [modified polymer (2mp')].

[0137] (III'): The amount of the epoxy compound shown in formula (2') is 0.1 to 50 parts by mass relative to the total of 100 parts by mass of polymer (A') and other polymers besides polymer (A').

[0138] Here, "the amount of epoxy compound shown in formula (2')" refers to the total amount of epoxy compound shown in formula (2') in the liquid crystal alignment agent and the total amount of epoxy compound shown in formula (2') constituting the modified polymer (2mp').

[0139] In addition, the polymer (A') in "total of 100 parts by mass of polymer (A') and other polymers besides polymer (A')" refers to the polymer (A') in the liquid crystal alignment agent and the polymer (A') constituting the modified polymer (2mp').

[0140] Therefore, for example, in the case where the liquid crystal alignment agent contains only 100 parts by mass of polymer (A'), 10 parts by mass of epoxy compound (B'), and 2000 parts by mass of solvent, the amount of epoxy compound represented by formula (2') in the liquid crystal alignment agent is 10 parts by mass relative to the total of 100 parts by mass of polymer (A') and other polymers besides polymer (A').

[0141] Furthermore, for example, in the case where the liquid crystal alignment agent contains only 120 parts by mass of modified polymer (2mp'), 100 parts by mass of other polymers (excluding polymer (A') and modified polymer (2mp')), and 4000 parts by mass of solvent, and the modified polymer (2mp') is the reaction product of 100 parts by mass of polymer (A') and 20 parts by mass of epoxy compound (B'), the amount of epoxy compound represented by formula (2') in the liquid crystal alignment agent is 10 parts by mass relative to the total of 100 parts by mass of polymer (A') and other polymers besides polymer (A').

[0142] In (III') above, the amount of the epoxy compound shown in formula (2') is 0.1 to 50 parts by mass relative to the total of 100 parts by mass of polymer (A') and other polymers other than polymer (A'), preferably 5 to 50 parts by mass, and more preferably 10 to 50 parts by mass.

[0143] <Polymers blended with or modified with epoxy compounds>

[0144] One embodiment of the liquid crystal alignment agent of the present invention satisfies at least one selected from the group consisting of (I) and (II) below.

[0145] (I): Contains polymer (A) and epoxy compound (B) as shown in formula (2).

[0146] (II): Contains the reaction product of polymer (A) and epoxy compound (B) [modified polymer (2mp)].

[0147] One embodiment of the liquid crystal alignment agent of the present invention satisfies at least one selected from the group consisting of (I') and (II') below and (III' below).

[0148] (I'): Contains polymer (A') and epoxy compound (B') as shown in formula (2').

[0149] (II'): Contains the reaction product of polymer (A') and epoxy compound (B') [modified polymer (2mp')].

[0150] (III'): The amount of the epoxy compound shown in formula (2') is 0.1 to 50 parts by mass relative to the total of 100 parts by mass of polymer (A') and other polymers besides polymer (A').

[0151] By configuring the liquid crystal alignment agent in various embodiments of the present invention in this way, the effect of reducing the accumulated charge of the obtained liquid crystal alignment film is increased. The reason for obtaining the above effect is uncertain, but it is believed that the reason is that a specific epoxy compound reacts with the carboxylic acid or amide group of polymer (A) or polymer (A'), thereby hindering the thermal imidization that occurs during the calcination of the liquid crystal alignment agent and reducing the imide ring.

[0152] Furthermore, compared to the form in which the polymer and epoxy compound are used together, the specific epoxy compound in the modified polymer form reacts efficiently with the carboxylic acid or amide group of polymer (A) or polymer (A'), thus further suppressing thermal imidization and increasing the effect of reducing charge accumulation, and is therefore preferred.

[0153] In this specification, "modified polymer (2mp)" also includes substances obtained by reacting the active hydrogen-containing groups (carboxyl, amino, hydroxyl, amide, etc.) of polymer (A) with the epoxy group of the epoxy compound shown in formula (2). Here, "partial reaction" means the state in which the reaction between the epoxy group and all the active hydrogen-containing groups proceeds and stops before becoming a modified polymer, and also includes a portion of the modified polymer that is not modified, a portion of the modified polymer that is partially modified, polymer (A), and / or the residual epoxy compound shown in formula (2).

[0154] For example, the "modified polymer (2mp)" in the liquid crystal composition of the present invention also includes substances such as the following.

[0155] (1): Polymer (A) and a partially modified polymer of the epoxy compound shown in formula (2).

[0156] (2): A mixture of polymer (A) and a partially modified polymer of the epoxy compound shown in formula (2), the remaining polymer (A) and the remaining epoxy compound shown in formula (2).

[0157] (3): A mixture of polymer (A) with a partially modified polymer of the epoxy compound shown in formula (2) and the remaining polymer (A).

[0158] (4): A mixture of polymer (A) and a partially modified polymer of the epoxy compound shown in formula (2) and the remaining epoxy compound shown in formula (2).

[0159] Furthermore, "modified polymer (2mp')" refers to the content in the above description of "modified polymer (2mp)" after replacing polymer (A) with polymer (A') and replacing the epoxy compound shown in formula (2) with the epoxy compound shown in formula (2').

[0160] The modified polymer (2mp) is obtained by reacting polymer (A) with the epoxy compound shown in formula (2). The same method can also be used to obtain the modified polymer (2mp'), which is the reaction product of a mixture of polymer (A') and the epoxy compound shown in formula (2').

[0161] In the mixture of polymer (A) and epoxy compound shown in formula (2) when the modified polymer (2mp) is obtained, the mixing ratio of polymer (A) and epoxy compound shown in formula (2) is not particularly limited. The epoxy compound shown in formula (2) is preferably 0.05 to 2 moles of 1 mole of amic acid group of polymer (A), more preferably 0.1 to 1.5 moles, and even more preferably 0.2 to 1.2 moles.

[0162] In the mixture of polymer (A') and epoxy compound of formula (2') when the modified polymer (2mp') is obtained, the mixing ratio of polymer (A') and epoxy compound of formula (2') is not particularly limited. The epoxy compound of formula (2') is preferably 0.05 to 2 moles of 1 mole of amic acid group of polymer (A'), more preferably 0.1 to 1.5 moles, and even more preferably 0.2 to 1.2 moles.

[0163] The reaction of polymer (A) used to obtain the modified polymer (2mp) with the epoxy compound shown in formula (2) can be carried out by stirring a mixture of polymer (A) and the epoxy compound shown in formula (2) at 20–120°C, preferably at 20–100°C, for 0.5–120 hours, and more preferably for 1–72 hours. The same method can be used to obtain the reaction product of polymer (A') and the epoxy compound shown in formula (2'), i.e., the modified polymer (2mp').

[0164] <Methods for manufacturing polymers (A) and (A')>

[0165] In the case where the polymer (A) (or (A')) used in this invention is a polyimide precursor having repeating units as shown in the above formula (1-a) (or (1'-a)), it can be synthesized, for example, by a known method as described in International Publication 2013 / 157586. Taking polymer (A) as an example, in the case of a polyamic acid having repeating units as shown in the above formula (1-a) where R1 is a hydrogen atom, it can be obtained by reacting the above-mentioned diamine with a tetracarboxylic acid dianhydride in a solvent (condensation). Furthermore, in the case of a polyamic acid ester having repeating units as shown in the above formula (1-a) where R1 is a group other than a hydrogen atom, it can be obtained, for example, by methods such as: [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.

[0166] Furthermore, by cyclizing (imidizing) the aforementioned polyimide precursor, a polyimide having repeating units as shown in formula (1-i) (or (1'-i)) can be obtained. It should be noted that the imidization rate referred to in this specification refers to, for example, the proportion of imide groups in the total amount of imide groups (i.e., repeating units as shown in formula (1-i)) and carboxyl groups (or their derivatives) (i.e., repeating units as shown in formula (1-a)) derived from tetracarboxylic dianhydride or its derivatives. In polyimides, the imidization rate does not necessarily have to be 100%, and can be adjusted arbitrarily according to the application and purpose. From the viewpoint of reducing the incidence of display defects, the imidization rate of the polyimide (A) (or polyimide (A')) of the specific polymer used in this invention is preferably 20-100%, more preferably 50-99%, and even more preferably 70-99%.

[0167] Methods for imidizing polyimide precursors include: thermal imidization, which involves heating a solution of the polyimide precursor while maintaining it in that state, and catalytic imidization (also known as chemical imidization), which involves adding a catalyst to a solution of the polyimide precursor.

[0168] The temperature at which the polyimide precursor is thermally imidized in solution is typically 100–400°C, preferably 120–250°C, and preferably carried out while removing water generated by the imidization reaction from the system.

[0169] Catalytic imidization of polyimide precursors can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor, typically at -20 to 250°C, preferably at 0 to 180°C, with stirring. The amount of basic catalyst is typically 0.5 to 30 molar times that of the amide acid groups, preferably 2 to 20 molar times, and the amount of acid anhydride is typically 1 to 50 molar times that of the amide acid groups, preferably 3 to 30 molar times. 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, trimellitic anhydride, and pyromellitic anhydride, among which acetic anhydride is preferred because it facilitates purification after the reaction. The imidization rate based on catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[0170] In the case of recovering the generated polyimide precursor or polyimide from the reaction solution of polyimide precursor or polyimide, the reaction solution can simply be precipitated by adding it to a solvent. Examples of solvents for precipitation include: methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer precipitated by adding it to the solvent can be recovered by filtration and then dried at room temperature or under normal or reduced pressure, or by heating. Furthermore, by repeatedly re-dissolving and re-precipitating the recovered polymer in an organic solvent 2 to 10 times, impurities in the polymer can be reduced. Examples of solvents for this process include: alcohols, ketones, or hydrocarbons. Using three or more solvents selected from these sources further improves the purification efficiency and is therefore preferred.

[0171] With regard to the molecular weight of the polymer used in this invention, taking into account the strength of the resulting liquid crystal alignment film, workability during film formation, and coating properties, the weight-average molecular weight determined by GPC (Gel Permeation Chromatography) is preferably set to 5,000 to 1,000,000, more preferably 10,000 to 150,000.

[0172] <Terminal Modifiers>

[0173] Alternatively, when synthesizing polymer (A) or polymer (A') of the present invention, a suitable end-modifying agent can be used together with the tetracarboxylic acid derivative component and the diamine component as described above to synthesize an end-modified polymer. The end-modified polymer has the effects of increased film hardness of the liquid crystal alignment film obtained by coating and improved adhesion properties between the sealant and the liquid crystal alignment film.

[0174] Examples of the ends of the polymer (A) or polymer (A') in this invention include: amino, carboxyl, anhydride, isocyanate, thioisocyanate, or derivatives thereof. The amino, carboxyl, anhydride, isocyanate, and thioisocyanate groups are obtained through conventional condensation reactions, and the aforementioned derivatives can be obtained, for example, by modifying the ends with the following end-modifying agents.

[0175] Examples of end-modifying agents include: acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic 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.; ditert-butyl dicarbonate, diallyl dicarbonate, etc. Dicarbonate compounds; 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, and n-octylamine; monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate, and naphthyl isocyanate; and thioisocyanate compounds such as ethyl isothiocyanate and allyl isothiocyanate.

[0176]

[0177] The proportion of the terminal modifier used relative to 100 moles of the total diamine component used is preferably 0.01 to 20 moles, more preferably 0.01 to 10 moles.

[0178] <Liquid Crystal Alignment Agent>

[0179] One embodiment of the liquid crystal alignment agent of the present invention satisfies at least one selected from the group consisting of (I) and (II) below.

[0180] (I): Contains polymer (A) and epoxy compound (B) as shown in formula (2).

[0181] (II): Contains the reaction product of polymer (A) and epoxy compound (B) [modified polymer (2mp)].

[0182] Furthermore, one embodiment of the liquid crystal alignment agent of the present invention satisfies at least one selected from the group consisting of (I') and (II') below.

[0183] (I'): Contains polymer (A') and epoxy compound (B') as shown in formula (2').

[0184] (II'): Contains the reaction product of polymer (A') and epoxy compound (B') [modified polymer (2mp')].

[0185] In addition to polymer (A), modified polymer (2mp), polymer (A'), or modified polymer (2mp'), the liquid crystal alignment agent of the present invention may also contain other polymers. Examples of other polymers include: polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivatives, polyacetal, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivatives, poly(meth)acrylate, etc.

[0186] Liquid crystal alignment agents are used to manufacture liquid crystal alignment films, and from the viewpoint of forming a uniform thin film, they are preferably in the form of a coating liquid. In the liquid crystal alignment agent of the present invention, a coating liquid containing the aforementioned polymer component and organic solvent is also preferred.

[0187] 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, 3-butoxy-N,N-... Dimethylpropionamide, 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.

[0188] 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 poor solvents used are described below, but are not limited thereto.

[0189] Examples include: diisopropyl ether, diisobutyl ether, diisobutylmethanol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxyethyl acetate, 1-methylpentyl acetate, 2-ethylethyl butyl 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-propanediol. Alcohols, 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.

[0190] 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 are preferred.

[0191] 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-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diethylene glycol diethyl ether; N-methyl- 2-Pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and 2,6-dimethyl-4-heptanone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and 2,6-dimethyl-4-heptanol; N-methyl-2-pyrrolidone, γ-butyrolactone, and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol dimethyl ether, etc. The 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.

[0192] The liquid crystal alignment agent of the present invention may also contain additional components (hereinafter also referred to as additive components) other than polymer components, epoxy compounds, and organic solvents. Examples of such additive components include: adhesion promoters for improving the adhesion between the liquid crystal alignment film and the substrate, and the adhesion between the liquid crystal alignment film and the sealant; compounds for improving the strength of the liquid crystal alignment film (hereinafter also referred to as crosslinking compounds); dielectrics, conductive substances, imidization promoters, etc., for adjusting the dielectric constant and resistance of the liquid crystal alignment film.

[0193] From the viewpoint of exhibiting good liquid crystal orientation and high film strength, the aforementioned crosslinking compound may be a compound having at least one group selected from the group consisting of ethylene oxide, oxetyl, protected isocyanate group, protected isothiocyanate group, group containing an oxazoline ring structure, group containing a Michaelis acid structure, cyclic carbonate group, and the group shown in formula (d) below; or a compound selected from the compound shown in formula (e) below.

[0194]

[0195] (R2 and R3 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH". * indicates a bonded bond. A indicates an (m+n) valence organic group having an aromatic ring. m represents an integer from 1 to 6, and n represents an integer from 0 to 4. R and R' each independently represent an alkyl group having 1 to 5 carbon atoms. Any hydrogen atom in the above aromatic ring may optionally be replaced by a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, or a fluoroalkenyl group having 2 to 10 carbon atoms.)

[0196] Specific examples of compounds having two or more ethylene oxide groups include compounds described in paragraph 0037 of Japanese Patent Application Publication No. 10-338880 and compounds with a triazine ring in their skeleton as described in International Patent Publication No. 2017 / 170483. These may include compounds containing nitrogen atoms, such as N,N,N',N'-tetraglycidyl-m-phenylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, and compounds shown in formulas (r-1) to (r-3) below.

[0197]

[0198] Specific examples of compounds having two or more oxetane groups include compounds having two or more oxetane groups as described in paragraphs 0170 to 0175 of International Publication No. 2011 / 132751.

[0199] Specific examples of compounds having two or more protected isocyanate groups include compounds having two or more protected isocyanate groups as described in paragraphs 0046 to 0047 of Japanese Patent Application Publication No. 2014-224978, and compounds having three or more protected isocyanate groups as described in paragraphs 0119 to 0120 of International Patent Application Publication No. 2015 / 141598, which can be compounds represented by the formulas (bi-1) to (bi-3) below.

[0200]

[0201] As a specific example of a compound having two protected isothiocyanate groups, the compounds having two or more protected isothiocyanate groups disclosed in Japanese Patent Application Publication No. 2016-200798 can be cited.

[0202] Specific examples of compounds having two or more groups containing an oxazoline ring structure include the compounds containing two or more oxazoline structures described in paragraph 0115 of Japanese Patent Application Publication No. 2007-286597.

[0203] As a specific example of a compound having two or more groups containing a Michaelis acid structure, the compound having two or more Michaelis acid structures described in International Publication No. 2012 / 091088 can be cited.

[0204] As a specific example of a compound having two or more cyclic carbonate groups, the compound described in International Publication No. 2011 / 155577 can be cited.

[0205] Examples of alkyl groups with 1 to 3 carbon atoms in R2 and R3, which are groups shown in formula (d) above, include methyl, ethyl, propyl, etc.

[0206] Specific examples of compounds having two or more groups shown in formula (d) above include: compounds having two or more groups shown in formula (d) above as described in International Publication No. 2015 / 072554, Japanese Patent Application Publication No. 2016-118753, and Japanese Patent Application Publication No. 2016-200798, etc., which can be compounds shown in formulas (hd-1) to (hd-8) below.

[0207]

[0208] Examples of (m+n) valence organic groups having an aromatic ring in A of formula (e) above include: (m+n) valence aromatic hydrocarbon groups with 6 to 30 carbon atoms, (m+n) valence organic groups formed by direct or linked groups of aromatic hydrocarbon groups with 6 to 30 carbon atoms, and (m+n) valence groups having aromatic heterocycles. Examples of such aromatic hydrocarbons include benzene and naphthalene. Examples of such aromatic heterocycles include the structures shown in the examples of nitrogen-containing heterocycles above. Examples of such linked groups include: -NR- (R represents a hydrogen atom or a monovalent organic group), alkylene groups with 1 to 10 carbon atoms, or groups formed by removing one hydrogen atom from the aforementioned alkylene groups, divalent or trivalent cyclohexane rings, etc. It should be noted that any hydrogen atom of the aforementioned alkylene group may optionally be replaced by an alkyl group with 1 to 6 carbon atoms, a fluorine atom, or an organic group such as trifluoromethyl. Examples of such alkyl groups as R in formula (e) above include: methyl, ethyl, propyl, etc. Specific examples include the compounds described in International Publication No. 2010 / 074269 and the compounds shown in formulas (e-1) to (e-10).

[0209]

[0210] The above-described compound is an example of a cross-linking compound, but is not limited thereto. Examples include, for instance, components other than those described above, disclosed on page 53, paragraph 0105 to page 55, paragraph 0116 of International Publication No. 2015 / 060357. Furthermore, two or more cross-linking compounds may be combined.

[0211] The content of the crosslinking compound in the liquid crystal alignment agent of the present invention is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent. From the viewpoint of promoting the progress of the crosslinking reaction and exhibiting good liquid crystal alignment, it is more preferably 1 to 15 parts by mass.

[0212] Examples of such sealing agents 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, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy 3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonylacetate, 9-triethoxysilyl-3,6-diazanonylacetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane Silane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxoethylidene)-3-aminopropyltrimethoxysilane, N-bis(oxoethylidene)-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyl Silane coupling agents include oxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane. When using silane coupling agents, from the viewpoint of exhibiting good liquid crystal alignment, the amount of polymer component contained in the liquid crystal alignment agent is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the polymer component.

[0213] 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 viscosity, volatility, etc., and is preferably 0.5 to 15% by mass, more preferably in the range of 1 to 10% by mass.

[0214] The particularly preferred range of solid component concentration varies depending on the method used to coat the liquid crystal alignment agent onto the substrate. For example, when using spin coating, the solid component concentration is particularly preferably in the range of 1.5 to 4.5% by mass. When using printing, the solid component concentration is particularly preferably in the range of 3 to 9% by mass, thereby setting the solution viscosity in the range of 12 to 50 mPa·s. When using inkjet printing, the solid component concentration is particularly preferably in the range of 1 to 5% by mass, thereby setting the solution viscosity in the range of 3 to 15 mPa·s.

[0215] <Liquid crystal alignment film / liquid crystal display element>

[0216] 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 for horizontally aligned or vertically aligned (VA type) liquid crystal alignment films, wherein the liquid crystal alignment film of the present invention is suitable for horizontally aligned liquid crystal display elements such as IPS or FFS types. The liquid crystal display element of the present invention includes the above-described liquid crystal alignment film. The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following steps (1) to (3).

[0217] (1) Process of coating liquid crystal alignment agent onto substrate

[0218] For example, 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. Here, the substrate is not particularly limited as long as it is highly transparent; it can also 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 the substrate is only on one side, an opaque material such as a silicon wafer can be used, and the electrodes can be made of light-reflecting materials such as aluminum. In addition, when manufacturing IPS or FFS type liquid crystal display elements, a substrate having electrodes composed of a patterned comb-shaped transparent conductive film or metal film and an opposing substrate without electrodes are used.

[0219] (2) The process of firing the coating film

[0220] After coating the liquid crystal alignment agent, preheating (pre-baking) is preferably performed first to prevent the alignment agent liquid from dripping. 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. A further heating (post-baking) process is then 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.

[0221] The coating formed in step (2) above can be kept in this state and used 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, which involves rubbing the coating in a certain direction with a roller made of cloth made of fibers such as nylon, rayon, or cotton; and light alignment treatment, which involves irradiating the coating with polarized or unpolarized radiation.

[0222] In photo-alignment 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. In the case of radiation polarization, it can be linearly polarized or partially polarized. Furthermore, when using linearly polarized or partially polarized radiation, irradiation can be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination thereof. When irradiating unpolarized radiation, the irradiation direction is set to an oblique direction.

[0223] (3) Manufacturing process of LCD cell

[0224] Prepare two substrates with liquid crystal alignment films formed thereon as described above, and place liquid crystal between the two substrates arranged opposite each other. Specifically, the following two methods can be listed. In the first method, firstly, 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 two substrates are bonded together at the periphery using a sealant, and a liquid crystal filling composition is injected into the cell gap defined by the substrate surface and the sealant. After contact with the film surface, the injection hole is sealed.

[0225] In addition, a second method is known as the ODF (One Drop Fill) method. For example, a UV-curable sealant is applied to a predetermined area on one of the two substrates forming the liquid crystal alignment film, and then a liquid crystal composition is dropped onto several predetermined points on the surface of the alignment film. The other substrate is then bonded with the alignment films facing each other, and the liquid crystal composition is spread across the entire surface of the substrate, contacting the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. Regardless of the method used, it is ideal to further heat the liquid crystal composition to a temperature at which it becomes an isotropic phase, and then slowly cool it to room temperature, thereby removing the flow alignment during liquid crystal filling.

[0226] There are no particular limitations on the liquid crystal composition described above; various liquid crystal compositions containing at least one liquid crystal compound (liquid crystal molecule) and having positive or negative dielectric anisotropy can be used. It should be noted that, hereinafter, liquid crystal compositions with positive dielectric anisotropy will be referred to as positive liquid crystals, and liquid crystal compositions with negative dielectric anisotropy will be referred to as negative liquid crystals.

[0227] The liquid crystal composition described above may contain liquid crystal compounds having fluorine atoms, hydroxyl groups, amino groups, fluorine-containing groups (e.g., trifluoromethyl), cyano groups, alkyl groups, alkoxy groups, alkenyl groups, isothiocyanate groups, heterocyclic groups, cycloalkanes, cycloolefins, steroidal skeletons, benzene rings, or naphthalene rings. It may also contain compounds having two or more rigid sites (mesocrystalline skeletons) that exhibit liquid crystal properties within the molecule (e.g., bimesocrystalline compounds formed by two rigid biphenyl structures or terphenyl structures linked by alkyl groups).

[0228] The liquid crystal composition may also be a nematic liquid crystal composition, a smectic liquid crystal composition, or a cholesteric liquid crystal composition.

[0229] Furthermore, from the viewpoint of improving liquid crystal orientation, the above-mentioned liquid crystal composition may further contain additives. Examples of such additives include: photopolymerizable monomers such as compounds with polymerizable groups; optically active compounds (e.g., S-811 manufactured by MERCK Co., Ltd.); antioxidants; ultraviolet absorbers; pigments; defoamers; polymerization initiators; or polymerization inhibitors, etc.

[0230] Examples of positive liquid crystal displays include: ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, and MLC-7081 manufactured by MERCK.

[0231] Examples of negative liquid crystals include MLC-6608, MLC-6609, MLC-6610, and MLC-7026-100 manufactured by MERCK.

[0232] In addition, MLC-3023 manufactured by MERCK is an example of a liquid crystal containing compounds with polymerizable groups.

[0233] It should be noted that when the coating has been brushed, the two substrates are arranged at a specified angle to each other with the brushing direction of each coating, such as being orthogonal or antiparallel.

[0234] As a sealant, epoxy resin containing a curing agent and alumina spheres as spacers can be used, for example. Nematic liquid crystals and smectic liquid crystals can be cited as examples, with nematic liquid crystals being preferred.

[0235] Furthermore, a liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell as needed. 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 composed of the H film itself, wherein the H film is formed by absorbing iodine while extending and oriented polyvinyl alcohol.

[0236] The IPS substrate, which is a comb-electrode substrate used in IPS (In-Plane Switching) mode, includes: a substrate; a plurality of linear electrodes formed on the substrate and configured in a comb-like shape; and a liquid crystal alignment film formed on the substrate in such a way as to cover the linear electrodes.

[0237] It should be noted that the FFS substrate, which is used as a comb electrode substrate in the FFS (Frindge Field Switching) mode, has: a substrate; a surface electrode formed on the substrate; an insulating film formed on the surface electrode; a plurality of linear electrodes formed on the insulating film and configured in a comb shape; and a liquid crystal alignment film formed on the insulating film in a manner that covers the linear electrodes.

[0238] Figure 1 This is a schematic cross-sectional view showing an example of a lateral electric field liquid crystal display element of the present invention, which is an example of an IPS mode liquid crystal display element.

[0239] exist Figure 1 In the lateral electric field liquid crystal display element 1 illustrated in the example, liquid crystal 3 is held between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2c and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 includes: a substrate 2a; a plurality of linear electrodes 2b formed on the substrate 2a and arranged in a comb-like shape; and a liquid crystal alignment film 2c formed on the substrate 2a to cover the linear electrodes 2b. The opposing substrate 4 includes: a substrate 4b and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2c is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4c is also, similarly, the liquid crystal alignment film of the present invention.

[0240] In this transverse electric field liquid crystal display element 1, when a voltage is applied to the linear electrode 2b, an electric field is generated between the linear electrodes 2b as shown by the electric field line L.

[0241] Figure 2 This is a schematic cross-sectional view showing another example of the transverse electric field liquid crystal display element of the present invention, which is an example of an FFS mode liquid crystal display element.

[0242] exist Figure 2 In the lateral electric field liquid crystal display element 1 illustrated in the example, liquid crystal 3 is held between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2h and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 includes: a substrate 2d; a surface electrode 2e formed on the substrate 2d; an insulating film 2f formed on the surface electrode 2e; a plurality of linear electrodes 2g arranged in a comb-like pattern formed on the insulating film 2f; and a liquid crystal alignment film 2h formed on the insulating film 2f to cover the linear electrodes 2g. The opposing substrate 4 includes: a substrate 4b and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2h is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4a is also, similarly, the liquid crystal alignment film of the present invention.

[0243] In this transverse electric field liquid crystal display element 1, when a voltage is applied to the surface electrode 2e and the linear electrode 2g, an electric field is generated between the surface electrode 2e and the linear electrode 2g as shown by the electric field line L.

[0244] In addition to the liquid crystal alignment film used for the purposes described above, the liquid crystal alignment film of the present invention can also be used for various other applications, such as liquid crystal alignment films for retardation films; liquid crystal alignment films for scanning antennas and liquid crystal array antennas; and liquid crystal alignment films for transmission-scattering type liquid crystal dimming elements. Furthermore, it can also be used for applications other than liquid crystal alignment films, such as protective films (e.g., protective films for color filters), spacer films, interlayer insulating films, anti-reflective films, wiring coating films, anti-static films, and motor insulating films (gate insulating films for flexible displays).

[0245] The liquid crystal display element of the present invention can be effectively applied to various devices, such as clocks, portable game consoles, word processors, laptops, car navigation systems, portable camcorders, PDAs (Personal Digital Assistants), digital cameras, portable telephones, smartphones, various monitors, LCD TVs, information displays, and other display devices.

[0246] Example

[0247] The present invention will be described in detail below with examples, but the invention is not to be construed as limited thereto. The abbreviations of the compounds used and the methods for determining their properties are described below.

[0248] (Organic solvents)

[0249] NMP: N-methyl-2-pyrrolidone.

[0250] GBL: γ-Butyrolactone.

[0251] BCS: Butyl cellosolve.

[0252] BCA: Butyl cellolytic acetate.

[0253] (acid dianhydride)

[0254] CA-1 to CA-4: These are compounds represented by the formulas (CA-1) to (CA-4) below.

[0255] (Diamine)

[0256] DA-1 to DA-5: These are compounds represented by the formulas (DA-1) to (DA-5) below.

[0257] (Terminal Modifier)

[0258] Boc2O: Di-tert-butyl dicarbonate.

[0259] (Epoxy compounds)

[0260] EP-1 to EP-3: These are compounds represented by the formulas (EP-1) to (EP-3) below.

[0261] (additive)

[0262] C-1: The compound represented by the following formula (C-1).

[0263] S-1:3-Epoxypropoxypropyltriethoxysilane.

[0264]

[0265] <Viscosity Measurement>

[0266] The viscosity of the solution was measured using a TVE-22H type E viscometer (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL, using a conical rotor TE-1 (1°34', R24), at a temperature of 25°C.

[0267] <Determination of imidization rate>

[0268] To NMR sample tubes (NMR standard sampling tubes, 20 mg of polyimide powder was added to a solution containing (Kusano Scientific Co., Ltd.), followed by 1.0 mL of a mixture of deuterated dimethyl sulfoxide ([D6]-DMSO and 0.05% tetramethylsilane (TMS)). The solution was then sonicated until completely dissolved. Proton NMR was measured at 500 MHz using an AVANCE III Fourier transform superconducting nuclear magnetic resonance (FT-NMR) device (manufactured by BRUKER Corporation).

[0269] Regarding the (chemical) imidization rate, the proton originating from the structure that remains unchanged before and after imidization is determined as the reference proton. The peak integral value of this proton, along with the peak integral value of the proton originating from the NH group of the amic acid appearing around 9.5–10.0 ppm, is calculated using the following formula. It should be noted that in the following formula, x represents the proton peak integral value originating from the NH group of the amic acid, y represents the peak integral value of the reference proton, and α represents the ratio of the reference proton to the number of protons in one NH group of the amic acid in the case of polyamic acid (imidization rate of 0%).

[0270] Imidification rate (%) = (1 - α·x / y) × 100

[0271] [Polymer Synthesis]

[0272] <Synthesis example 1>

[0273] DA-1 (8.04 g, 40.2 mmol), DA-2 (4.36 g, 10.9 mmol), DA-3 (12.2 g, 21.9 mmol), and NMP (98.4 g) were added to a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature while nitrogen was being introduced, allowing it to dissolve. Then, under ice-cold conditions, CA-1 (9.40 g, 47.4 mmol) and NMP (37.6 g) were added, and the mixture was stirred at 50 °C for 2 hours. After cooling to room temperature, CA-2 (4.65 g, 23.7 mmol) and NMP (18.6 g) were added, and the mixture was stirred at room temperature for 2 hours to obtain a 20% by mass solution of polyamic acid (PAA-1) (viscosity: 1320 mPa·s).

[0274] Measure 100 g of the obtained polyamic acid (PAA-1) solution into a 200 mL Erlenmeyer flask with a stir bar, add Boc2O (1.24 g, 5.68 mmol), and stir at 40 °C for 15 hours to obtain a solution of end-modified polyamic acid.

[0275] The obtained end-modified polyamic acid solution (100 g) was measured into a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. NMP (66.7 g), acetic anhydride (14.2 g), and pyridine (4.70 g) were added. After stirring at room temperature for 30 minutes, the mixture was reacted at 60 °C for 4 hours. The reaction solution was then added to methanol (650 g), and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 80 °C to obtain polyimide (SPI-1) powder. The imidization rate of this polyimide powder was 90%.

[0276] NMP (70.4 g) was added to the obtained polyimide powder (9.60 g), and the mixture was stirred at 70 °C for 24 hours to dissolve it, thus obtaining a polyimide (SPI-1) solution.

[0277] <Synthesis example 2>

[0278] DA-4 (1.99 g, 10.00 mmol), DA-5 (1.98 g, 10.0 mmol), and NMP (29.2 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred at room temperature until dissolved. CA-3 (2.50 g, 10.0 mmol) and NMP (7.55 g) were then added to the diamine solution, and the mixture was stirred at 50 °C for 2 hours. Then, under ice-cold conditions, CA-4 (2.71 g, 9.20 mmol) and NMP (14.8 g) were added, and the mixture was stirred at 50 °C for 6 hours, thus obtaining a 15% polyamic acid (PAA-2) solution (viscosity: 532 mPa·s).

[0279] Synthesis of Modified Polymers

[0280] <Synthesis Example 3>

[0281] A solution (30.0 g) of polyamic acid (PAA-2) obtained in Synthesis Example 2 was measured into a 50 mL flask equipped with a stirrer and a nitrogen inlet tube. EP-1 (0.44 g, 5.87 mmol, 0.3 mol parts per mole of the amic acid portion of polyamic acid (PAA-2)) was added, and the mixture was stirred at 70 °C for 18 hours to obtain a solution of modified polyamic acid (PAA-2-1).

[0282] <Synthesis Examples 4 to 10>

[0283] As shown in Table 1, the type, amount, and stirring time of the epoxy compound in the reaction were changed, and the same operation as in Synthesis Example 3 was performed to obtain solutions of modified polyamic acid (PAA-2-2) to (PAA-2-8).

[0284] [Table 1]

[0285]

[0286] [Preparation of Liquid Crystal Alignment Agent]

[0287] <Example 1>

[0288] Using a solution of polyimide (SPI-1) obtained in Synthesis Example 1 and a solution of modified polyamic acid (PAA-2-1) obtained in Synthesis Example 3, the solutions were diluted with NMP, GBL, BCS, and BCA. Additive (C-1) was added at a ratio of 3 parts by mass relative to 100 parts by mass of the total polymer. The mixture was stirred at room temperature for 2 hours, resulting in a liquid crystal alignment agent (1) with a polymer composition ratio of (SPI-1):(PAA-2-1) = 30:70 (converted mass ratio of solid components), a polymer solid component concentration of 4% by mass, and a solvent composition ratio of NMP:GBL:BCS:BCA = 30:46:15:5 (mass ratio). No abnormalities such as turbidity or precipitation were found in this liquid crystal alignment agent; it was a homogeneous solution.

[0289] <Examples 2-9, Comparative Example 1>

[0290] The polymers and additives used were changed as shown in Table 2 below, and the same procedure as in Example 1 was followed to obtain liquid crystal alignment agents (2) to (9) and (R1).

[0291] <Example 10>

[0292] Using the polyimide (SPI-1) solution obtained in Synthesis Example 1 and the polyamic acid (PAA-2) solution obtained in Synthesis Example 2, the solutions were diluted with NMP, GBL, BCS, and BCA. Epoxy compound (EP-1) and additive (C-1) were added in amounts of 5 parts by mass and 3 parts by mass relative to 100 parts by mass of the total polymer, respectively. The mixture was stirred at room temperature for 2 hours, resulting in a liquid crystal alignment agent (10) with a polymer composition ratio of (SPI-1):(PAA-2) = 30:70 (converted mass ratio of solid components), a polymer solid component concentration of 4% by mass, and a solvent composition ratio of NMP:GBL:BCS:BCA = 30:46:15:5 (mass ratio). No abnormalities such as turbidity or precipitation were found in this liquid crystal alignment agent; it was a homogeneous solution.

[0293] <Examples 11-13>

[0294] The types and amounts of additives used were changed as shown in Table 2 below. Otherwise, the operation was the same as in Example 10, thereby obtaining liquid crystal alignment agents (11) to (13).

[0295] <Example 14>

[0296] Using the polyamic acid (PAA-2) solution obtained in Synthesis Example 2, the solution was diluted with NMP, GBL, BCS, and BCA. An epoxy compound (EP-3) was added at a ratio of 15 parts by mass relative to 100 parts by mass of the total polymer, and the mixture was stirred at room temperature for 2 hours. The resulting solution was then filtered using a 0.5 μm filter, yielding a liquid crystal alignment agent (14) with a solvent composition ratio of NMP:GBL:BCS:BCA = 30:46:15:5 (mass ratio) and a polymer solids concentration of 4% by mass (Table 2 below). No abnormalities such as turbidity or precipitation were observed in this liquid crystal alignment agent; it was a homogeneous solution.

[0297] <Comparative Examples 2-4>

[0298] The polymers and additives used were changed as shown in Table 2 below, and the same procedure as in Example 14 was followed to obtain liquid crystal alignment agents (R2) to (R4).

[0299] [Table 2]

[0300]

[0301] Table 2 shows the amount (parts by mass) of epoxy compounds. * () indicates the amount of 100 parts by mass of the epoxy compound (B) relative to the polymer (A) and other polymers.

[0302] Table 2 shows the amount (parts by mass) of epoxy compounds. ** () represents the amount of 100 parts by mass of the epoxy compound (B') relative to the polymer (A') and other polymers.

[0303] In Table 2, the amount (molar parts) of the epoxy compound represents the amount of 1 molar part of the epoxy compound relative to the amic acid group of the polymer (A').

[0304] In Comparative Example 4, ※ indicates the amount (mole parts) of 1 mole part of amic acid groups of the epoxy compound relative to the polymer (SPI-1).

[0305] [Fabrication of an FFS-driven LCD cell]

[0306] A liquid crystal cell with a fringe field switching (FFS) mode liquid crystal display element was manufactured.

[0307] First, a substrate with electrodes was prepared. The substrate used was a 30mm × 35mm glass substrate with a thickness of 0.7mm. On the substrate, an ITO electrode with a dense pattern constituting the counter electrode was formed as the first layer. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by CVD (chemical vapor deposition) was formed as the second layer. The SiN film of the second layer had a thickness of 500nm and functioned as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning the ITO film was disposed as the third layer, forming two types of pixels: a first pixel and a second pixel. Each pixel was 10mm long and approximately 5mm wide. At this point, the counter electrode of the first layer and the pixel electrode of the third layer were electrically insulated by the SiN film of the second layer.

[0308] The pixel electrode of the third layer has a comb-like shape in which multiple central portions are arranged in parallel with a width of 3μm and an inner angle of 160°, and are separated by a 6μm interval. A pixel has a first region and a second region bounded by the line connecting the curved portions of the multiple electrode elements.

[0309] When comparing the first and second regions of each pixel, the electrode elements constituting their pixel electrodes are formed in different directions. Specifically, based on the brushing direction of the liquid crystal alignment film (described later), the electrode elements forming the pixel electrodes in the first region of the pixel are at a clockwise angle of 10°, and the electrode elements forming the pixel electrodes in the second region of the pixel are at a counterclockwise angle of 10°. In other words, in the first and second regions of each pixel, the directions of the rotational movement (in-plane transition) of the liquid crystal within the substrate surface caused by the voltage applied between the pixel electrode and the counter electrode are opposite to each other.

[0310] Next, the liquid crystal alignment agent obtained above was filtered using a 1.0 μm pore size filter and then spin-coated onto the prepared electrode substrate and a glass substrate with ITO film on the back side and columnar spacers with a height of 4 μm. After drying on a heating plate at 80°C for 5 minutes, it was fired in a hot air circulating oven at 230°C for 20 minutes to obtain a polyimide film with a thickness of 60 nm. The polyimide film was brushed using rayon cloth (Yoshikawa Chemical YA-20R) (roller diameter: 120 mm, roller speed: 1000 rpm, moving speed: 30 mm / sec, pressing length: 0.3 mm, brushing direction: tilted at 10° relative to the third layer IZO comb electrode), and then ultrasonically irradiated in pure water for 1 minute to clean it. Water droplets were removed using a blower. Then, it was dried at 80°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. Using two substrates with liquid crystal alignment films as a group, a sealant (Mitsui Chemicals XN-1500T) was printed on the substrate to leave a liquid crystal injection port. Another substrate was then bonded together with the liquid crystal alignment film surfaces facing each other and the brushing direction antiparallel. The sealant was then cured by heat treatment at 150°C for 60 minutes, creating an empty cell with a cell gap of 4 μm. Negative liquid crystal MLC-7026-100 (MERCK) was injected into this empty cell using a reduced-pressure injection method, and the injection port was sealed, resulting in an FFS-type liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour and placed at 23°C overnight for evaluation.

[0311] [Evaluation of DC Charge Accumulation]

[0312] The FFS-driven liquid crystal cell fabricated above is placed between two polarizing plates arranged orthogonally with polarization axes. The pixel electrode and the counter electrode are short-circuited and at the same potential. LED backlight is shone from under the two polarizing plates. The angle of the liquid crystal cell is adjusted so that the brightness of the LED backlight transmitted light measured on the two polarizing plates is minimized.

[0313] Next, while applying an AC voltage of 30Hz to the liquid crystal cell, the V-T curve (voltage-transmittance curve) was measured, and the AC voltage at which the relative transmittance became 23% or 100% was calculated as the driving voltage.

[0314] In evaluating the amount of accumulated charge, AC drive with 100% relative transmittance is applied for 45 minutes. During this time, the minimum offset voltage value is measured every 3 minutes, and the change from the start of the measurement to 45 minutes later is calculated as the amount of DC accumulated charge. The accumulated charge affects the display in the form of liquid crystal alignment disorder and image retention, significantly reducing the display quality level of the liquid crystal display element. Therefore, it can be said that the less DC accumulated charge generated during driving, the better.

[0315] In this invention, the accumulated charge of the liquid crystal alignment agent without epoxy modification or the addition of epoxy compounds was evaluated as 100%. Specifically, the values ​​in Examples 1-13 were evaluated as the value when the accumulated charge of Comparative Example 1 was 100%, the value in Example 14 was evaluated as the value when the accumulated charge of Comparative Example 3 was 100%, and the value in Comparative Example 4 was evaluated as the value when the accumulated charge of Comparative Example 2 was 100%. The smaller the value, the better.

[0316] It should be noted that the DC charge accumulation evaluation according to the above method was performed under the temperature condition that the liquid crystal cell temperature was 23°C.

[0317] [Determination of the rate of charge easing]

[0318] The FFS-driven liquid crystal cell fabricated above is placed between two polarizing plates arranged orthogonally with polarization axes. The pixel electrode and the counter electrode are short-circuited and at the same potential. LED backlight is shone from under the two polarizing plates. The angle of the liquid crystal cell is adjusted so that the brightness of the LED backlight transmitted light measured on the two polarizing plates is minimized.

[0319] Next, while applying an AC voltage of 30Hz to the liquid crystal cell, the V-T curve (voltage-transmittance curve) was measured, and the AC voltage at which the relative transmittance became 23% or 100% was calculated as the driving voltage.

[0320] In the image retention evaluation, the liquid crystal cell was driven by an AC voltage of 30 Hz at a relative transmittance of 23% while simultaneously driven by a DC voltage of 1 V for 45 minutes. Then, the application of the DC voltage was stopped, and the cell was driven for another 15 minutes solely under the AC voltage.

[0321] The evaluation criteria were as follows: if the relative transmittance gradually decreased to below 25% before 10 minutes had elapsed from the point when the DC voltage was stopped, it was defined as "0"; if it took more than 10 minutes for the relative transmittance to decrease to below 25%, it was defined as "×".

[0322] It should be noted that the image retention evaluation according to the above method is performed under the temperature condition that the liquid crystal cell temperature is 23°C.

[0323] [Afterimage Evaluation Based on Long-Term Communication]

[0324] The image retention evaluation based on long-term AC drive in this review evaluates image retention caused by the deterioration of the alignment performance of the liquid crystal alignment film (also known as AC image retention), which is different from the image retention caused by accumulated charge (also known as DC image retention) mentioned above. The distinction between AC and DC image retention is disclosed, for example, in paragraph 0037 of Japanese Patent Application Publication No. 2016-106281.

[0325] Using the FFS-driven liquid crystal cell fabricated above, an AC voltage of ±5V at a frequency of 60Hz was applied for 120 hours at a constant temperature of 60°C. Then, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left at room temperature for one day.

[0326] After placement, the liquid crystal cell is positioned between two polarizing plates orthogonally arranged with their polarization axes aligned. The backlight is then illuminated without applied voltage, and the cell's orientation angle is adjusted to minimize the transmitted light brightness. The rotation angle Δ is then calculated to determine when the liquid crystal cell rotates from the darkest angle in the second region of the first pixel to the darkest angle in the first region. The same angle Δ is calculated for the second pixel by comparing the second and first regions.

[0327] Regarding the afterimage characteristics based on long-term AC drive, a smaller angle Δ is better. An angle Δ less than 0.3° is rated as "〇", Δ greater than 0.3° but less than 0.6° is rated as "△", and Δ greater than 0.6° is rated as "×".

[0328] [Evaluation of flickering during operation]

[0329] The FFS-driven liquid crystal cell fabricated above is placed between two polarizing plates orthogonally arranged with polarization axes, and the LED backlight is lit without applying voltage (light source: LED, luminance: 20000 cd / m²). 2 The configuration angle of the liquid crystal cell was adjusted to minimize the brightness of the transmitted light. Then, while applying an AC voltage of 30 Hz to the liquid crystal cell, the V-T curve (voltage-transmittance curve) was measured, and the AC voltage at which the relative transmittance reached 23% was calculated as the driving voltage.

[0330] In the flicker measurement, the pre-lit LED backlight was temporarily turned off and left in the dark for 72 hours. Then, the LED backlight was turned on again. Simultaneously with the backlight illuminating, an AC voltage of 30Hz with a relative transmittance of 23% was applied to drive the liquid crystal cell for 30 minutes, and the flicker amplitude was tracked. Regarding the flicker amplitude, the transmitted light from the LED backlight passing through the two polarizers and the liquid crystal cell was read using a 34970A data logger switch unit (manufactured by Agilent Technologies) connected via a photodiode and an I-V conversion amplifier. The value calculated based on this data using the following formula was taken as the flicker level.

[0331] Scintillation level (%) = {scintillation amplitude / (2 × z)} × 100

[0332] In the above formula, z is the brightness value read by the data collection / data recorder switch unit 34970A when driven by an AC voltage with a frequency of 30Hz and a relative transmittance of 23%.

[0333] Regarding the evaluation of flicker, a flicker level of less than 1.5% was defined as "○" 30 minutes after the start of LED backlighting and AC voltage application, and a flicker level of more than 1.5% was defined as "×" within 30 minutes.

[0334] The evaluation of the flicker level according to the above method was carried out under temperature conditions where the temperature of the liquid crystal cell was 23°C.

[0335] Fabrication of a liquid crystal cell for evaluating pretilt angle and voltage retention rate.

[0336] First, a substrate with electrodes was prepared. The substrate was a glass substrate measuring 30mm × 40mm and 0.7mm thick. On the substrate, an ITO electrode with a film thickness of 35nm was formed, and the electrode was a stripe pattern with a length of 40mm and a width of 10mm.

[0337] Next, the liquid crystal alignment agent obtained above was filtered using a filter with a pore size of 1.0 μm and then coated onto the prepared substrate with electrodes using a spin-coating method. After drying on a heating plate at 80°C for 2 minutes, it was fired in an infrared heating furnace at 230°C for 20 minutes to form a coating film with a thickness of 60 nm, thus obtaining a substrate with a liquid crystal alignment film. After brushing the liquid crystal alignment film using rayon cloth (Yoshikawa Chemical YA-20R) (roller diameter: 120 mm, roller speed: 1000 rpm, moving speed: 20 mm / sec, pressing length: 0.4 mm), it was cleaned by ultrasonic irradiation in pure water for 1 minute. After removing water droplets using a blower, it was dried at 80°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. Two substrates with liquid crystal alignment films were prepared. On one substrate, 4μm spacers were dispersed on the surface of the liquid crystal alignment film. A sealant (Mitsui Chemicals XN-1500T) was then printed onto it. The other substrate was then bonded together with the film surfaces facing each other, in the opposite direction of the brushing. The substrate was then heated at 150°C for 60 minutes to cure the sealant, creating a blank cell. Negative liquid crystal MLC-7026 (MERCK) was injected into the blank cell using a reduced-pressure injection method. The injection port was then sealed to obtain the liquid crystal cell. The resulting liquid crystal cell was then heated at 120°C for 1 hour and placed at 23°C overnight before evaluation.

[0338] [Determination of pretilt angle]

[0339] The pretilt angle within the liquid crystal cell was measured using the AxoScan Mueller Matrix Polarimeter manufactured by Optometrics. A lower pretilt angle is better. A pretilt angle below 2.0° is rated "0", and a pretilt angle above 2.0° is rated "×".

[0340] [Evaluation of voltage retention rate after backlight tolerance test]

[0341] The aforementioned liquid crystal cell was subjected to a high-brightness backlight (20000 cd / m²) with a surface temperature of 50°C. 2 The cells were placed under light for 120 hours. After placement, a voltage of 1V was applied to the liquid crystal cell at 60°C for 60μsec, and the voltage was measured after 16.7ms. The voltage retention rate was calculated and used as the voltage retention rate after the backlight resistance test.

[0342] A voltage retention rate of 95% or higher after the backlight resistance test is rated as "◎", less than 95% but more than 85% is rated as "〇", less than 85% but more than 75% is rated as "△", and less than 75% is rated as "×".

[0343] [result]

[0344] Regarding the liquid crystal display elements using the liquid crystal alignment agents of Examples 1 to 14 and Comparative Examples 1 to 4 described above, the evaluation results of the DC charge accumulation amount, charge accumulation mitigation speed, afterimage based on long-term AC drive, flicker generated during drive, pretilt angle, and voltage retention rate after backlight tolerance test are shown in Table 3 below.

[0345] [Table 3]

[0346]

[0347] Explanation of reference numerals in the attached figures

[0348] 1: Lateral electric field liquid crystal display element; 2: Comb electrode substrate; 2a: Substrate; 2b: Linear electrode; 2c: Liquid crystal alignment film; 2d: Substrate; 2e: Surface electrode; 2f: Insulating film; 2g: Linear electrode; 2h: Liquid crystal alignment film; 3: Liquid crystal; 4: Opposite substrate; 4a: Liquid crystal alignment film; 4b: Substrate; L: Electric field line.

Claims

1. A liquid crystal alignment agent, characterized in that, Satisfying at least one of the following groups I and II, I: containing a polymer (A) and an epoxy compound (B) as shown in formula (2) below, said polymer (A) having repeating units selected from the group consisting of repeating units shown in formula (1-a) below and repeating units shown in formula (1-i) below. II: The reaction product comprising polymer (A) and epoxy compound (B) as shown in formula (2) below, wherein the polymer (A) has repeating units selected from the group consisting of repeating units shown in formula (1-a) below and repeating units shown in formula (1-i) below. In formulas (1-a) and (1-i), X1 represents a tetravalent organic group; Y1 represents a divalent organic group; each of R1 and Z1 independently represents a hydrogen 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 tert-butoxycarbonyl group, a 9-fluorenylmethoxycarbonyl group, an alkylsilyl group with 1 to 6 carbon atoms, or a monovalent organic group formed by replacing at least one of the hydrogen atoms of the alkyl, alkenyl, or alkynyl groups with a halogen atom or a nitro group; R1 and Z1 may optionally be the same or different, wherein X1 in II is a tetravalent organic group derived from an aromatic tetracarboxylic acid dianhydride or a derivative thereof. In formula (2), R1 to R4 each independently represent a hydrogen atom, hydroxyl group, halogen atom, nitro group, cyano group, alkyl group with 1 to 5 carbon atoms, alkenyl group with 2 to 5 carbon atoms, alkynyl group with 2 to 5 carbon atoms, or a monovalent organic group formed by replacing at least one of the hydrogen atoms of the alkyl group, alkenyl group or alkynyl group with a hydroxyl group, halogen atom, nitro group or cyano group; wherein at least one of R1 to R4 represents a group other than a hydrogen atom.

2. The liquid crystal alignment agent according to claim 1, wherein, The amount of the epoxy compound represented by formula (2) is 0.1 to 50 parts by mass relative to a total of 100 parts by mass of the polymer (A) and other polymers besides polymer (A).

3. The liquid crystal alignment agent according to claim 1 or 2, wherein, The epoxy compound represented by formula (2) contains at least one of the epoxy compounds represented by formula (e2-1) to formula (e2-25).

4. The liquid crystal alignment agent according to claim 1 or 2, wherein, X1 in I is a tetravalent organic group derived from aliphatic tetracarboxylic dianhydride or its derivatives, a tetravalent organic group derived from alicyclic tetracarboxylic dianhydride or its derivatives, or a tetravalent organic group derived from aromatic tetracarboxylic dianhydride or its derivatives.

5. The liquid crystal alignment agent according to claim 1 or 2, wherein, Y1 is a divalent organic group formed by removing two amino groups from a diamine, wherein the diamine is selected from diamines represented by the following formula (O), diamines having amide or urea bonds, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, and the following formula (d o In the group consisting of diamines, 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, and diamines having the group "-N(D)-", D in the group "-N(D)-" represents a protecting group that is removed by heating and replaced by a hydrogen atom. In formula (O), Ar represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring; the two Ars may be identical or different, and any hydrogen atom on the ring in Ar may be substituted with a monovalent substituent; P is an integer of 0 or 1; Q2 represents -(CH2). n - or - (CH2) n A group formed by replacing at least a portion of -CH2- with any one of -O-, -C(=O)-, and -O-C(=O)-, wherein -(CH2-) n In this context, n is an integer from 2 to 18. Formula (d) O In the case of multiple m, each m can be arbitrarily the same or different.

6. The liquid crystal alignment agent according to claim 1 or 2, wherein, Y1 is a divalent organic group formed by removing two amino groups from a diamine selected from the group consisting of diamines having a nitrogen-containing structure, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, and diamines having a carboxyl group.

7. A liquid crystal alignment agent, characterized in that, It satisfies the condition of being selected from at least one of the following groups consisting of I' and II', and the following III'. I': Contains a polymer (A') and an epoxy compound (B') as shown in formula (2'), wherein the polymer (A') has repeating units selected from the group consisting of repeating units shown in formula (1'-a) and repeating units shown in formula (1'-i); II': Contains the reaction product of the polymer (A') and the epoxy compound (B'); III': The amount of the epoxy compound represented by formula (2') is 0.1 to 50 parts by mass relative to a total of 100 parts by mass of the polymer (A') and other polymers besides the polymer (A'). In formulas (1'-a) and (1'-i), X1' represents a tetravalent organic group; Y1' represents a group selected from the following formula (d) Y The partial structure shown in '-1) and the following formula (d) Y The divalent organic group consisting of at least one partial structure of the structure shown in '-2) and a nitrogen-containing heterocycle, wherein the nitrogen-containing heterocycle is pyrrole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, purine, quinoline, isoquinoline, naphthidine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, or hexamethyleneimine; each of the two R1' and Z1' independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a tert-butoxycarbonyl group, a 9-fluorenemethoxycarbonyl group, an alkylsilyl group having 1 to 6 carbon atoms, or a monovalent organic group formed by replacing at least one of the hydrogen atoms of the alkyl group, the alkenyl group, or the alkynyl group with a halogen atom or a nitro group; R1' and Z1' may optionally be the same or different. Formula (d) Y In formula '-1), R represents a hydrogen atom or a monovalent organic group; Y '-1)~(d Y In '-2), any hydrogen atom on the benzene ring is optionally substituted with a monovalent substituent; * indicates a bond. In equation (2'), R o The term refers to an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, a phenyl group, a monovalent organic group q formed by introducing -O- between carbon-carbon bonds in the alkyl group, or a monovalent organic group q formed by replacing at least one hydrogen atom in the alkyl group, the alkenyl group, the alkynyl group, the phenyl group, or the monovalent organic group q with a hydroxyl group, a halogen atom, a nitro group, or a cyano group.

8. The liquid crystal alignment agent according to claim 7, wherein, The polymer (A') is a polymer having more than 5 mol% of the repeating units shown in formula (1'-a) of all repeating units.

9. The liquid crystal alignment agent according to claim 7 or 8, wherein, The epoxy compound represented by formula (2') is a compound represented by formulas (e2'-1) to (e2'-11) below, and one or more epoxy compounds represented by formula (2') are used in combination.

10. The liquid crystal alignment agent according to claim 1 or 7, wherein, The liquid crystal alignment agent further contains crosslinking compounds and / or binding agents.

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

12. A liquid crystal display element comprising the liquid crystal alignment film as described in claim 11.

Images