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

Abstract

Provided is a liquid crystal alignment agent capable of obtaining a liquid crystal alignment film having high adhesion between the liquid crystal alignment film and a sealant and high in-plane uniformity of liquid crystal alignment restriction force, the liquid crystal alignment film, and a liquid crystal display element using the liquid crystal alignment film. A liquid crystal alignment agent containing a polymer (P) which is at least one selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic acid component containing at least one selected from the group consisting of tetracarboxylic dianhydride and derivatives thereof and a diamine component containing a diamine represented by the following formula (2), and a polyimide which is an imidization product of the polyimide precursor. (The meanings of the symbols in the above formula are defined in the description.)

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 displays (LCDs) are widely used as display units in personal computers, smartphones, mobile phones, televisions, and other devices. An LCD typically includes: a liquid crystal layer sandwiched between a display 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; and a thin-film transistor (TFT) that converts the electrical signals supplied to the pixel electrodes; etc. 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).

[0003] The most commonly used liquid crystal alignment film in industry is manufactured by rubbing the surface of a film formed on an electrode substrate, which is composed of polyamic acid and / or polyimide formed by imidizing it, in one direction using a cloth such as cotton, nylon, or polyester. Rubbing is a simple and highly productive method useful in industry. As an alternative to rubbing, photoalignment methods are known, which impart alignment capabilities to liquid crystals by irradiating them with polarized radiation. Regarding photoalignment methods, methods utilizing photoisomerization reactions, photocrosslinking reactions, and photodecomposition reactions have been proposed (see, for example, Non-Patent Literature 1, Patent Literature 1, 2, and 3).

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 9-297313 Patent Document 2: Japanese Patent Application Publication No. 2004-206091 Patent Document 3: WO2017 / 047596 Non-patent literature Non-patent literature 1: "Functional Materials", November 1997, Vol. 17, No. 11, pp. 13-22 Summary of the Invention

[0005] The problem that the invention aims to solve In recent years, large-screen and high-definition liquid crystal display elements have become the mainstream. In addition, small display terminals such as smartphones, tablets, and car navigation systems have become increasingly popular, further raising the requirements for high-quality liquid crystal display elements.

[0006] For example, in the aforementioned small display terminals, to ensure as many display surfaces as possible, the width of the sealant used between the substrates bonding the liquid crystal display elements needs to be narrower than before. In such cases, to prevent damage to the liquid crystal display elements, the adhesion (also known as sealing) between the liquid crystal alignment film and the sealant needs to be higher than before.

[0007] Furthermore, from the perspective of improving the quality of liquid crystal display elements, it is necessary to improve the in-plane uniformity of liquid crystal alignment constraint.

[0008] Therefore, in view of the above, the object of the present invention is to provide a liquid crystal alignment agent that can produce a liquid crystal alignment film with high adhesion between the liquid crystal alignment film and the sealant and high in-plane uniformity of liquid crystal alignment constraint force.

[0009] Solution for solving the problem The inventors conducted in-depth research and discovered that the above-mentioned technical problems can be solved by using a liquid crystal alignment agent containing specific components, thereby completing the present invention.

[0010] Specifically, the present invention has the following solution.

[0011] A liquid crystal alignment agent comprising a polymer (P) selected from at least one polyimide precursor obtained using a tetracarboxylic acid component and a diamine component, and a polyimide of an imide derivative thereof, wherein the tetracarboxylic acid component comprises at least one selected from the group consisting of tetracarboxylic dianhydrides and their derivatives, and the diamine component comprises a diamine represented by the following formula (2). (In equation (2), R) 21 ~R 24 Independently representing hydrogen atoms or *-CO2R, R 21 ~R 24 At least one of them represents *-CO2R. R represents a protecting group (DO) that is thermally substituted with a hydrogen atom. One or more hydrogen atoms on the benzene ring bonded to the amino group are optionally substituted with a monovalent group other than *-CO2R. L represents a single bond or a divalent linking group. It should be noted that, throughout this specification, the following can be listed as halogen atoms: fluorine, chlorine, bromine, iodine, etc., with * indicating a bond. Boc represents tert-butyloxycarbonyl. Furthermore, "tert-" is also called "t-".

[0012] Invention Effects By using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film with high adhesion to the liquid crystal alignment film and sealant and high in-plane uniformity of liquid crystal alignment constraint force can be obtained. Attached Figure Description

[0013] Figure 1 This is a schematic cross-sectional view illustrating an example of a liquid crystal display element with a lateral electric field mode according to the present invention.

[0014] Figure 2 This is a schematic cross-sectional view illustrating another example of a liquid crystal display element with a lateral electric field mode according to the present invention.

[0015] Figure 3 It is a simplified diagram of the test sample substrate used in the evaluation of the adhesion between the sealant and the substrate. Detailed Implementation

[0016] <Polymer (P)> The liquid crystal alignment agent of the present invention contains a polymer (P), which is at least one selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic acid component and a diamine component, and a polyimide as an imide derivative of the polyimide precursor. The tetracarboxylic acid component includes at least one selected from the group consisting of tetracarboxylic dianhydrides and their derivatives, and the diamine component includes the diamine shown in formula (2) above (also referred to as a specific diamine (p) in the present invention). The polymer (P) may be one or more of the following.

[0017] Here, the polyimide precursor is a polymer such as polyamic acid or polyamic acid ester that can be imidized to obtain polyimide.

[0018] (Tetracarboxylic acid component) Polyamic acid (P'), a polyimide precursor of polymer (P), can be obtained, for example, by polymerization of the aforementioned specific diamine component with a tetracarboxylic dianhydride component.

[0019] In the case of manufacturing polymer (P), the tetracarboxylic acid component that reacts with the diamine component can be not only tetracarboxylic dianhydride, but also derivatives of tetracarboxylic dianhydride such as tetracarboxylic acid, tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters or tetracarboxylic acid dialkyl ester dihalides.

[0020] For example, tetracarboxylic dianhydrides or their derivatives that can be used to manufacture polymers (P') include, for instance, acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, or their derivatives (hereinafter also referred to as specific tetracarboxylic acid components). More preferably, they comprise tetracarboxylic dianhydrides or their derivatives having at least one partial structure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring. In particular, it is even more preferable that they comprise tetracarboxylic dianhydrides or their derivatives having at least one structure selected from the group consisting of a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring.

[0021] It should be noted that aromatic tetracarboxylic dianhydrides are obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to the aromatic ring.

[0022] Acyclic 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.

[0023] Alicyclic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to the alicyclic structure. None of these four carboxyl groups are bonded to an aromatic ring. Furthermore, 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.

[0024] As a specific example of a tetracarboxylic acid dianhydride or its derivatives that can be used to manufacture polymers (P'), the following schemes can be listed.

[0025] 1,2,3,4-Butanetetracarboxylic dianhydride or (Q)2-A (Q represents a monovalent succinic anhydride structure, A represents a divalent organic group formed by substituting at least any of the following groups: -CH2-, an alkylene group having 2 to 18 carbon atoms, or a portion thereof having -CH2- substituted by a phenylene group, -O-, -NR- (R represents a hydrogen atom or a methyl group), -C(=O)-NR- (R represents a hydrogen atom or a methyl group), -C(=O)-O-, and -O-C(=O)-)-, etc.) acyclic aliphatic tetracarboxylic dianhydrides; tetracarboxylic dianhydrides, 1,2,3,4-butanetetracarboxylic dianhydride ... Cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic acid dianhydride, 2,3,5-tricarboxylated cyclopentylacetic acid dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)tetrahydronaphthyl-1,2-dicarboxylic acid anhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, bis Alicyclic tetracarboxylic dianhydrides include: cyclo[2.2.2]octyl-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclic[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, 2,4,6,8-tetracarboxylic bicyclic[3.3.0]octane-2:4,6:8-dianhydride; pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-diphenyl sulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4... Aromatic tetracarboxylic acid dianhydrides such as 4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)-2,2-diphenylpropane dianhydride, ethylene glycol bis(triphenylene oxide), 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 4,4'-carbonyldiphthalic anhydride, 4,4'-(1,4-phenylenedioxy)bis(phthalic anhydride) or 4,4'-(1,4-phenylenedimethyl)bis(phthalic anhydride); and tetracarboxylic acid dianhydrides as described in Japanese Patent Application Publication No. 2010-97188. (In equation (1), R) 1 ~R 4 Each can independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, an alkynyl group with 2 to 6 carbon atoms, a monovalent organic group containing a fluorine atom with 1 to 6 carbon atoms, or a phenyl group. From the viewpoint of high photoreactivity, the tetracarboxylic dianhydride or its derivatives that can be used to manufacture polymers (P') are preferably the tetracarboxylic dianhydride or its derivatives shown in the above formula (1).

[0026] R is the expression in equation (1) above. 1 ~R 4 Specific examples of alkyl groups having 1 to 6 carbon atoms include: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, etc. As for the aforementioned R... 1 ~R 4 Specific examples of alkenyl groups with 2 to 6 carbon atoms include vinyl, propenyl, and butenyl groups, which can be linear or branched. 1 ~R 4 Specific examples of alkynyl groups with 2 to 6 carbon atoms include: ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, etc. As for the aforementioned R... 1 ~R 4 Examples of monovalent organic groups containing fluorine atoms with 1 to 6 carbon atoms include: fluoromethyl, trifluoromethyl, pentafluoroethyl, pentafluoropropyl, trifluoromethoxy, 2,2,2-trifluoroethyl, 2,2,2-trifluoroethoxy, etc.

[0027] From the perspective of high photoreactivity, R is preferred. 1 ~R 4 At least two of them represent groups other than hydrogen atoms as defined above. Furthermore, from the viewpoint of high photoreactivity, R is more preferred. 1 and R 4 R represents a group other than a hydrogen atom. 2 and R 3 This refers to the case of hydrogen atoms.

[0028] From the perspective of high photoreactivity, R 1 ~R 4 Each is independently a hydrogen atom or a methyl group, more preferably R. 1 ~R 4 At least one of them is methyl, and R is more preferably methyl. 1 ~R 4 At least two of them are methyl groups. R is the most preferred. 1 and R 4 For methyl, R 2 and R 3 The case where the atom is hydrogen.

[0029] Preferred specific examples of the tetracarboxylic dianhydride or its derivatives shown in formula (1) above include: 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-difluoro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic dianhydride, etc.

[0030] The proportion of the specific tetracarboxylic acid component used relative to 1 mole of the total tetracarboxylic acid component used in the polymer (P) is more preferably 10 mol% or more, further preferably 20 mol% or more, and most preferably 50 mol% or more.

[0031] The tetracarboxylic acid component used to manufacture polymer (P) may also include other tetracarboxylic acid components besides the specific tetracarboxylic acid components mentioned above.

[0032] Specifically, tetracarboxylic acid dianhydrides and their derivatives of formulas [CA-1] to [CA-26] can be listed. When other tetracarboxylic acid components are used in addition to the specific tetracarboxylic acid component mentioned above, the content of the specific tetracarboxylic acid component is more preferably 95 mol% or less, and more preferably 90 mol% or less, relative to 1 mole of all tetracarboxylic acid components used in the polymer (P).

[0033] Furthermore, the content of other tetracarboxylic acid components relative to 1 mole of all tetracarboxylic acid components used in polymer (P) is more preferably 5 mol% to 90 mol%, more preferably 10 to 80 mol%, and most preferably 10 to 50 mol%.

[0034] (Specific diamine (p)) The specific diamine (p) of the present invention is the diamine shown in formula (2) above. The specific diamine (p) above can be used alone or in combination of two or more.

[0035] R in equation (2) above 21 ~R 24 The hydrogen atom or *-CO2R is represented independently, where R represents the protecting group (D0) that is replaced by a hydrogen atom by heat.

[0036] The protective base (DO) is preferably a protective base that detaches from heat at 80°C or higher, more preferably a protective base that detaches from heat at 100°C or higher. Furthermore, from the viewpoint of properly obtaining the effects of the present invention, the protective base (DO) is preferably a protective base that detaches from heat at 300°C or lower, more preferably a protective base that detaches from heat at 250°C or lower, and even more preferably a protective base that detaches from heat at 200°C or lower.

[0037] As a preferred example of the protecting base (D0), structures selected from the group consisting of the following formulas (a-1) to (a-6) can be listed. (In formula (a-2), R) 2a R 2b Each can independently represent an alkyl group having 1 to 3 hydrogen atoms or carbon atoms. R 2c (This refers to alkyl groups with 1 to 5 carbon atoms.) In formula (2) above, one or more hydrogen atoms on the benzene ring bonded to the amino group are optionally replaced by a monovalent group other than *-CO2R. Examples of such monovalent groups include: halogen atoms, alkyl groups with 1 to 3 carbon atoms, alkenyl groups with 2 to 3 carbon atoms, alkoxy groups with 1 to 3 carbon atoms, fluoroalkyl groups with 1 to 3 carbon atoms, fluoroalkenyl groups with 2 to 3 carbon atoms, fluoroalkoxy groups with 1 to 3 carbon atoms, cyano groups, nitro groups, etc.

[0038] In formula (2) above, L represents a single bond or a divalent linking group. Preferred specific examples of the divalent linking group in L include: -CH2-, -O-, -O-C(=O)-, -C(=O)-, -N(R)- (R represents a hydrogen atom, methyl or Boc), -N(R)-C(=O)-N(R)- (R represents a hydrogen atom, methyl or Boc. The two Rs may optionally be the same or different), cyclohexene, or alkylene groups having 2 to 18 carbon atoms.

[0039] In this embodiment, any -CH2- group of the alkylene group is optionally replaced by -O-, -O-C(=O)-, -C(=O)-, -N(R)- (R represents a hydrogen atom, methyl group, or Boc group), -N(R)-C(=O)- (R represents a hydrogen atom, methyl group, or Boc group), cyclohexene, or phenylene (wherein the oxygen atom is not adjacent to the oxygen atom). Furthermore, any hydrogen atom on the cyclohexene or phenylene group is optionally replaced by a halogen atom or an alkyl or alkoxy group having 1 to 5 carbon atoms.

[0040] More preferred examples of the divalent linking groups in L mentioned above include: -O-, -O-C(=O)-, -C(=O)-, -N(R)- (R represents a hydrogen atom, methyl group, or Boc), -N(R)-C(=O)- (R represents a hydrogen atom, methyl group, or Boc), -N(R)-C(=O)-N(R)- (R represents a hydrogen atom, methyl group, or Boc. The two Rs may optionally be the same or different), and -(CH2). p -、-O-(CH2) p -O-, -(CH2) p -O-C(=O)-(CH2) q -、-(CH2) p -N(R)-(CH2) q - (R represents a hydrogen atom, methyl group, or Boc), - (CH2) p -N(R)-C(=O)-N(R)-(CH2) q - (R represents a hydrogen atom, a methyl group, or a Boc. The two Rs may be the same or different), -O- (CH2) p -O-(CH2) q -O-, -(CH2) p’ -O-C(=O)-(CH2) q -C(=O)-O-(CH2) r’ -、-(CH2) p’ -C(=O)-O-(CH2) q -O-C(=O)-(CH2) r’ -、-(CH2) p’ -O-C (=O) -Q-C (=O) -O- (CH2) q’ - (Q represents phenylene or cyclohexene), - (CH2) p’ -C(=O)-O-Q-O-C(=O)-(CH2) q’ - (Q represents phenylene or cyclohexene).

[0041] In the above, p is an integer from 1 to 6, preferably an integer from 2 to 6. q is an integer from 1 to 6, more preferably an integer from 2 to 6, and even more preferably an integer from 2 to 4.

[0042] p', q', and r' are each an independent integer from 0 to 6. Furthermore, 0 ≤ p' + q' ≤ 10 and 2 ≤ p' + q + r' ≤ 16 are satisfied.

[0043] From the viewpoint of improving liquid crystal orientation, it is preferable that the two amino groups in the above formula (2) are bonded together at the para position relative to the linking group L.

[0044] R 21 ~R24 At least two of them represent *-CO2R, preferably R. 21 ~R 24 The two symbols in the text represent *-CO2R.

[0045] Furthermore, regarding the content of a specific diamine (p) relative to the diamine component, it is preferably 5 mol% or more, more preferably 30 mol% or more, and even more preferably 50 mol% or more, relative to 1 mole of the diamine component used to manufacture the polymer (P).

[0046] As a more preferred specific example of the diamine shown in formula (2) above, the following formulas (2-1) to (2-4) can be listed. (In the formula, t-Bu represents tert-butyl.) The diamine component used to manufacture the polymer (P) may also include diamines other than the specific diamine (p) (hereinafter also referred to as other diamines). When other diamines are used in addition to the specific diamine (p), the content of the specific diamine (p) relative to 1 mole of the diamine component used to manufacture the polymer (P) is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less.

[0047] Examples of other diamines are listed below, but they are not limited to these. The aforementioned other diamines can be used alone, in combination of two or more, or in combination of three or more.

[0048] p-Phenylenediamine, 2,3,5,6-tetramethylp-phenylenediamine, 2,5-dimethylp-phenylenediamine, m-phenylenediamine, 2,4-dimethylm-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, and other phenylenediamines; 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl and other diaminobiphenyl compounds; the following formula (d AL The diamine shown (preferably the following formula (d)) represents a diamine. AL -1) ~ (d) AL-8) shows the following diamines: 1,7-bis(4-aminophenoxy)heptane, 1,7-bis(3-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1,8-bis(3-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,9-bis(3-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, and 1,10-bis(3-aminophenoxy)decane. , 1,11-bis(4-aminophenoxy)undecane, 1,11-bis(3-aminophenoxy)undecane, 1,12-bis(4-aminophenoxy)dodecane, 1,12-bis(3-aminophenoxy)dodecane, 1,2-bis(6-amino-2-naphthoxy)ethane, 1,2-bis(6-amino-2-naphthyl)ethane or 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine), and the following formula (d BZ -1) ~ (d) BZ-2) The diamines shown, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene and other diamines with diphenyl ether structures (hereinafter, they are also collectively referred to as first diamines); N,N'-bis(4-aminophenyl)-cyclobutane-(1,2,3,4)-tetracarboxylic acid diimide, N,N'-bis(4-aminophenyl)-1,3-dimethylcyclobutane-(1,2,3,4)-tetracarboxylic acid diimide, N,N'-bis( Diamines with a tetracarboxylic acid diimide structure, such as 2,2'-bis(trifluoromethyl)-4'-amino-1,1'-biphenyl-4-yl)-cyclobutane-(1,2,3,4)-tetracarboxylic acid diimide; aromatic diamines with an azobenzene structure, such as 4,4'-diaminoazobenzene; aromatic diamines with a stilbene structure, such as 4,4'-diaminostilbene; aromatic diamines with a toluene structure, such as diaminotoluene; aromatic diamines with a chalcone structure, such as 4,4'-diaminochalcone; 1,4-phenylenebis(4-aminobenzoate), 1,4-phenylenebis(3-aminobenzoate), 1,3-phenylenebis(4-aminobenzoate), 1,3-phenylenebis(3-aminobenzoate); bis(4-aminophenyl)-p-phenylene Aromatic diamines with phenylbenzoate structures, such as dicarboxylate, bis(3-aminophenyl) terephthalate, bis(4-aminophenyl) isophthalate, and bis(3-aminophenyl) isophthalate; or (E)-4-aminophenyl 3-(4-aminophenyl)acrylate, (E)-4-amino-2-methylphenyl 3-(4-aminophenyl)acrylate, (E)-4-aminophenylethyl 3-(4-aminophenyl)acrylate, (E,E)-bis-(4'-aminophenyl)1,3-phenylenediacrylate, (E,E)-bis-(4'-aminophenyl)1,4-phenylenediacrylate, or 4-aminophenyl(2E)-3-(4-aminophenyl)-2-methyl-2-acrylate, etc., with cinnamic acid ester structures. Aromatic diamines with photooriented groups include those with aromatic groups; diamines with photopolymerizable groups at the ends, such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallyl aniline; diamines with free radical polymerization initiator functions, such as 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylacetone, 2-(4-(2-hydroxy-2-methylpropionyl)phenoxy)ethyl ester, and 3,5-diaminobenzoic acid; diamines with amide bonds, such as 4,4'-diaminobenzoylaniline; and diamines with urea bonds, such as 1,3-bis(4-aminophenyl)urea, 1,3-bis(4-aminobenzyl)urea, and 1,3-bis(4-aminophenylethyl)urea.2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(3-amino-4-methylphenyl)propane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3- Bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene; 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, N-[3-(1H-imidazol-1-yl)propyl]3,5-diaminobenzamide, 4-[4-[(4-aminophenoxy)methyl]-4,5 [-dihydro-4-methyl-2-oxazolyl]-aniline, or heterocyclic diamines such as those shown in formulas (z-1) to (z-13), or diamines with a diphenylamine structure such as 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, diamines shown in formula (z-14), N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-phenylenediamine, which are diamines with a diphenylamine structure and have the ability to be selected freely The structure of at least one nitrogen-containing atom (hereinafter also referred to as a specific nitrogen-containing atom structure, wherein the specific nitrogen-containing atom structure is a diamine (wherein, the molecule does not have an amino group bonded to a protecting group that is thermally removed and substituted with a hydrogen atom) of at least one nitrogen-containing atom structure from the group consisting of nitrogen-containing heterocycles, secondary amino groups, and tertiary amino groups; 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-Diaminobenzoic acid, 4,4'-Diaminobiphenyl-3-carboxylic acid, 4,4'-Diaminodiphenylmethane-3-carboxylic acid, 1,2-bis(4-aminophenyl)ethane-3-carboxylic acid, 4,4'-Diaminobiphenyl-3,3'-dicarboxylic acid, 4,4'-Diaminobiphenyl-2,2'-dicarboxylic acid, 3,3'-Diaminobiphenyl-4,4'-dicarboxylic acid, 3,3'-Diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-Diaminodiphenylmethane-3,3'-dicarboxylic acid, 1,2-bis(4-aminophenyl)ethane-3-carboxylic acid Diamines containing carboxyl groups, such as ethane-3,3'-dicarboxylic acid and 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid; 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; and those containing the group "-N(D)-" (where D represents a protecting group that is removed and replaced by a hydrogen atom by heat, preferably a carbamate protecting group, more preferably) of the following formulas (5-1) to (5-9). The tert-butyloxycarbonyl group is selected. This excludes diamines with a steroidal skeleton, such as the specific diamines (p) mentioned above, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl ester of 3,5-diaminobenzoate, cholesteryl ester of 3,5-diaminobenzoate, cholesteryl ester of 3,5-diaminobenzoate, and lanosteryl ester of 3,6-bis(4-aminobenzoyloxy)cholestan, and diamines with a steroidal skeleton as shown in formulas (V-1) to (V-2) below; 2,7-diaminofluorene or 9,9-bis(4-aminophenyl)fluorene, etc. Aromatic diamines, such as those with a siloxane bond, are included; diamines with a siloxane bond, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; acyclic aliphatic diamines, such as m-phenylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, and hexamethylenediamine, are included; alicyclic diamines, such as 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, and 4,4'-methylenebis(cyclohexylamine), are included; and diamines formed by bonding two amino groups to any of the formulas (Y-1) to (Y-167) described in WO2018 / 117239, are included. (Ar1 and Ar 1’ Each represents a benzene ring, a biphenyl structure, or a naphthalene ring, wherein one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring are optionally substituted with monovalent groups. L1 and L 1’Each represents a single bond, -O-, -C(=O)-, or -O-C(=O)-. A represents a divalent organic group consisting of -CH2-, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group formed by inserting at least any group selected from -O-, -C(=O)-O-, and -O-C(=O)- between the carbon-carbon bonds of the alkylene group. Any hydrogen atom in A may optionally be replaced by a halogen atom.

[0049] One or more hydrogen atoms on the aforementioned benzene ring, biphenyl structure, or naphthalene ring are optionally replaced by a monovalent group. Examples of such monovalent groups include: halogen atoms, alkyl groups with 1 to 3 carbon atoms, alkenyl groups with 2 to 3 carbon atoms, alkoxy groups with 1 to 3 carbon atoms, fluoroalkyl groups with 1 to 3 carbon atoms, fluoroalkenyl groups with 2 to 3 carbon atoms, fluoroalkoxy groups with 1 to 3 carbon atoms, alkoxycarbonyl groups with 2 to 3 carbon atoms, cyano groups, nitro groups, etc. (in formula (d) AL In (-1), k is an integer from 1 to 2.

[0050] In formula (d) AL In -2), the total of l, m and n is 1 to 12.

[0051] In formula (d) AL In (-5), the sum of m1, m2 and n is 1 to 12.

[0052] In formula (d) AL In (-7), the total of m1, m2 and n is 3 to 12.

[0053] In formula (d) AL In (-8), the total of l, m and n is 3 to 12.

[0054] The above formula (d) AL -1) ~ (d) AL In (-8), one or more hydrogen atoms on the benzene ring are optionally replaced by a monovalent group. Specific examples of such monovalent groups include Ar1 and Ar mentioned above. 1’ (The example shown is a monovalent group.) In the above equation (V-1), m and n are integers from 0 to 3, satisfying 1 ≤ m + n ≤ 4. j is an integer of 0 or 1. X 1 It represents - (CH2) a- (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. R 1 Monovalent groups include fluorine atoms, alkyl groups containing fluorine atoms with 1 to 10 carbon atoms, alkoxy groups containing fluorine atoms with 1 to 10 carbon atoms, alkyl groups with 1 to 10 carbon atoms, alkoxy groups with 1 to 10 carbon atoms, and alkoxyalkyl groups with 2 to 10 carbon atoms.

[0055] In the above formula (V-2), X 2 Represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. In the presence of two m, n, X... 1 R 1 In each case, they each have the above definitions independently.

[0056] The nitrogen-containing heterocycles that a diamine with the aforementioned specific nitrogen-containing structure can possess include, for example: 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.

[0057] From the viewpoint of improving liquid crystal orientation, the aforementioned other diamines may be selected from the group consisting of the aforementioned first diamine, diamines having a tetracarboxylic acid diimide structure, diamines having an amide bond, diamines having a urea bond, and diamines having a group "-N(D)-".

[0058] In addition, the diamines of the following formulas [DA-1] to [DA-103] can also be used as other diamines. The content of the aforementioned other diamines relative to 1 mole of the diamine component used to manufacture the polymer (P) is more preferably 5 to 85 mol%, more preferably 10 to 80 mol%, and even more preferably 15 to 80 mol%. Furthermore, when two or more other diamines are included, the content of each diamine constituting each other diamine may be 30 mol% or less.

[0059] (Liquid crystal alignment agent) The liquid crystal alignment agent of the present invention is a liquid composition of a polymer (P) and other components used as needed, preferably dispersed or dissolved in a suitable solvent.

[0060] The liquid crystal alignment agent of the present invention may also contain polymers other than polymer (P). Specific examples of other polymers include polymers selected from the group consisting of: at least one polymer (also referred to as polymer (B) in the present invention) selected from the group consisting of a polyimide precursor obtained using a diamine component that does not contain the specific diamine (p) described above and a polyimide as an imide derivative of the polyimide precursor; polysiloxanes; polyesters; polyamides; polyureas; polyorganosiloxanes; cellulose derivatives; polyacetals; polystyrene derivatives; poly(styrene-maleic anhydride) copolymers; poly(isobutylene-maleic anhydride) copolymers; poly(vinyl ether-maleic anhydride) copolymers; poly(styrene-phenylmaleimide) derivatives; and poly(meth)acrylates.

[0061] Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley), and GSM301 (manufactured by Gifu Shellac Manufacturing). Specific examples of poly(isobutylene-maleic anhydride) copolymers include ISOBAM-600 (manufactured by Kuraray). Specific examples of poly(vinyl ether-maleic anhydride) copolymers include Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland).

[0062] Among these, polymer (B) is preferred in terms of reducing the residual image from residual DC.

[0063] The other polymers mentioned above can be used alone, or in combination of two or more. The proportion of the other polymers relative to 100 parts by mass of the total polymers contained in the liquid crystal alignment agent is preferably 90 parts by mass or less, more preferably 10 to 90 parts by mass, and even more preferably 20 to 80 parts by mass.

[0064] (Polymer (B)) Specific examples of the tetracarboxylic acid component used to manufacture the above-described polymer (B) include, among preferred examples, compounds identical to those exemplified in polymer (P), such as: acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, or derivatives thereof. More preferably, the tetracarboxylic acid component used to manufacture polymer (B) comprises a tetracarboxylic dianhydride or derivatives thereof having at least one partial structure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring (hereinafter also referred to as the specific tetracarboxylic acid component (B)).

[0065] Furthermore, the content of the aforementioned specific tetracarboxylic acid component (B) is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 50 mol% or more, relative to 1 mole of all tetracarboxylic acid components used to manufacture polymer (B).

[0066] As a diamine component for obtaining polymer (B), examples of diamines exemplified in the polymer (P) described above can be included. Preferably, at least one diamine selected from the group consisting of the following diamines (also referred to as diamine (b) in this invention): the aforementioned first diamine, a diamine having a urea bond, a diamine having an amide bond, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl) Hexafluoropropane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(3-amino-4-methylphenyl)propane, 4,4'-benzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, diamines having specific nitrogen-containing structures as described above, diamines having carboxyl groups as described above, 4-(2-(methylamino)ethyl)aniline, and 4-(2-aminoethyl)aniline. The diamine components described above can be used alone or in combination of two or more.

[0067] When using the specific diamine (b) described above, its content is preferably 10 mol% or more of the total diamine component used to manufacture the polymer (B), more preferably 20 mol% or more. When using a diamine other than the specific diamine (b), the content of the specific diamine (b) is preferably 90 mol% or less of 1 mol of the total diamine component used to manufacture the polymer (B), more preferably 80 mol% or less.

[0068] (Manufacturing of polyamic acid) The production of polyamic acid is carried out by reacting a diamine component with a tetracarboxylic acid component in an organic solvent. Regarding the ratio of the tetracarboxylic acid component to the diamine component used in the polyamic acid production reaction, the anhydride group of the tetracarboxylic acid component is preferably in a ratio of 0.5 to 2 equivalents to the amino group of the diamine component, more preferably 0.8 to 1.2 equivalents. Similar to conventional polycondensation reactions, the closer the equivalent of the anhydride group of the tetracarboxylic acid component is to 1 equivalent, the larger the molecular weight of the resulting polyamic acid.

[0069] The reaction temperature for manufacturing polyamic acid is preferably -20 to 150°C, more preferably 0 to 100°C. Furthermore, the reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours. Polyamic acid can be manufactured at any concentration, but the concentration is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. Alternatively, the reaction can be carried out at a high concentration initially, followed by the addition of solvent.

[0070] Specific examples of the aforementioned organic solvents include: cyclohexanone, cyclopentanone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolinone. Furthermore, when the polymer has high solvent solubility, solvents such as methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, or diethylene glycol monoethyl ether can be used.

[0071] (Manufacturing of polyamic acid esters) Polyamates can be obtained, for example, by the following known methods: [I] reacting the polyamic acid obtained by the above method with an esterifying agent, [II] reacting a tetracarboxylic acid diester with a diamine, [III] reacting a tetracarboxylic acid diester dihalide with a diamine, etc.

[0072] (Manufacturing of polyimide) Regarding polyimides, they can be obtained by cyclizing (imidizing) the aforementioned polyimide precursors such as polyamic acid or polyamic ester. It should be noted that the imidization rate mentioned in this specification refers to the proportion of imide groups in the total amount of imide groups and carboxyl groups (or their derivatives) derived from tetracarboxylic dianhydride or its derivatives. The imidization rate does not necessarily have to be 100% and can be adjusted arbitrarily according to the application and purpose.

[0073] Methods for imidizing polyimide precursors include: thermal imidization by heating a solution of the polyimide precursor while maintaining it in that state, and catalytic imidization by adding a catalyst to a solution of the polyimide precursor.

[0074] The temperature at which the polyimide precursor is thermally imidized in solution is preferably 100–400°C, more preferably 120–250°C, and preferably the process is carried out while removing the water generated by the imidization reaction from the system.

[0075] The 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, preferably at -20 to 250°C, more preferably at 0 to 180°C. The amount of the basic catalyst is preferably 0.5 to 30 molar times that of the ammonium acid groups, more preferably 2 to 20 molar times, and the amount of the acid anhydride is preferably 1 to 50 molar times that of the ammonium acid groups, more preferably 3 to 30 molar times. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, or trioctylamine, among which pyridine is preferred due to its moderate basicity in promoting the reaction. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, or pyromellitic anhydride, among which acetic anhydride is preferred because it facilitates purification after the reaction. The imidization rate based on the catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[0076] In recovering the generated polyimide precursor or polyimide from the reaction solution of the polyimide precursor or polyimide, the reaction solution can be simply 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.

[0077] When manufacturing the polyimide precursor and polyimide of this invention, a suitable capping agent can also be used together with a tetracarboxylic acid component containing tetracarboxylic dianhydride or its derivative and a diamine component containing a diamine to manufacture a capped polymer. The capped polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained from the coating and improving the adhesion properties between the sealant and the liquid crystal alignment film.

[0078] Examples of polyimide precursors and ends of polyimides in this invention include: amino, carboxyl, anhydride, or groups derived from the capping agents described below. Amino, carboxyl, and anhydride groups can be obtained through conventional condensation reactions or by capping with the following capping agents.

[0079] Examples of capping agents include: acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynyl phthalic anhydride, etc.; dicarbonate diester compounds such as ditert-butyl dicarbonate and diallyl dicarbonate; acryloyl chloride, methyl... Chlorocarbonyl compounds such as acryloyl chloride and nicotinyl chloride; monoamine compounds such as aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; and isocyanates with unsaturated bonds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, 2-acryloyloxyethyl isocyanate, and 2-methacryloyloxyethyl isocyanate.

[0080] The proportion of the capping agent used relative to 100 moles of the total diamine components used is preferably 0.01 to 20 moles, more preferably 0.01 to 10 moles.

[0081] The weight-average molecular weight (Mw) of the polyimide precursor and polyimide, as determined by gel permeation chromatography (GPC) based on polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC, is preferably 15 or less, more preferably 10 or less, and even more preferably 5 or less. By being within this molecular weight range, good liquid crystal alignment of the liquid crystal display element can be ensured.

[0082] The organic solvent contained in the liquid crystal alignment agent of the present invention is not particularly limited as long as it uniformly dissolves the polymer (P), and other polymers may be added as needed. Examples include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactic acid, N,N-dimethylpropionamide, tetramethylurea, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, and 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.

[0083] 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 poor solvents are described below, but are not limited thereto. The content of the poor 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 poor solvent are appropriately selected according to the coating apparatus, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

[0084] Examples of unsuitable solvents 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-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol. 2-(2-Butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, 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, cyclohexyl acetate, 4-methyl-2-pentyl 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.

[0085] 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.

[0086] Preferred combinations of good and bad solvents include: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-dimethyllactic acid and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone, ethyl 3-ethoxypropionate, and... and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, ethyl 3-ethoxypropionate and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether; N-ethyl-2-pyrrolidone, ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether; N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate; N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether; N,N-dimethyl lactamide and ethylene glycol monobutyl ether; N,N-dimethyl lactamide and propylene glycol diacetate; N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, diethylene glycol monoethyl ether and butyl cellosolve acetate; N-methyl-2-pyrrolidone Ketones, diethylene glycol monomethyl ethers, and butyl cellosolve acetate; N,N-dimethyl lactamide and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone; N-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol dimethyl ether; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutylmethanol;N-Methyl-2-pyrrolidone, γ-butyrolactone, and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, diethylene glycol diethyl ether, and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and propylene glycol diacetate; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and diisobutyl ketone; N-ethyl-2-pyrrolidone, γ-butyrolactone, and diisobutyl ketone; N-ethyl-2-pyrrolidone, N,N-dimethyl Lactic acid and diisobutyl ketone; N-methyl-2-pyrrolidone, ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate; γ-butyrolactone, ethylene glycol monobutyl ether acetate and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, ethylene glycol monobutyl ether acetate and propylene glycol dimethyl ether; N-methyl-2-pyrrolidone, 4-methyl-2-pentyl acetate and ethylene glycol monobutyl ether; N-ethyl-2-pyrrolidone, cyclohexyl acetate and 4-hydroxy-4-methyl-2-pentanone; cyclohexanone and propylene glycol monomethyl ether; cyclopentanone and propylene glycol monomethyl ether; N-methyl-2-pyrrolidone, cyclohexanone and propylene glycol monomethyl ether, etc.

[0087] (Liquid crystal alignment agent) The liquid crystal alignment agent of the present invention contains the above-mentioned polymer (P) and, as needed, the above-mentioned other polymers and the above-mentioned organic solvent.

[0088] The total content of polymers in the liquid crystal alignment agent of the present invention can be appropriately varied according to the desired coating thickness. From the perspective of forming a uniform and defect-free coating, it is preferably 1% by mass or more; from the perspective of solution storage stability, it is preferably 10% by mass or less. A particularly preferred total polymer content is 2 to 8% by mass.

[0089] The content of polymer (P) used in this invention is preferably 1 to 100% by mass relative to the total amount of polymers contained in the liquid crystal alignment agent, more preferably 10 to 100% by mass, and particularly preferably 20 to 100% by mass.

[0090] In addition to the polymer (P), the other polymers, and the organic solvent described above, the liquid crystal alignment agent of the present invention may also contain other components (hereinafter also referred to as additive components). Examples of such additive components include: at least one crosslinking compound selected from the group consisting of crosslinking compounds having the following substituents and crosslinking compounds having polymerizable unsaturated groups; functional silane compounds; metal chelating compounds; curing accelerators; surfactants; antioxidants; sensitizers; preservatives; compounds for adjusting the dielectric constant and resistance of the obtained liquid crystal alignment film, wherein the substituents are selected from at least one of ethylene oxide, oxetyl, terminal isocyanate, oxazoline, cyclic carbonate, hydroxyalkyl, and alkoxy.

[0091] Preferred specific examples of the aforementioned crosslinking compounds include: ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, dibromonepentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, bisphenol A type epoxy resins such as EPIKOTE 828 (manufactured by MITSUBISHI CHEMICAL), bisphenol F type epoxy resins such as EPIKOTE 807 (manufactured by MITSUBISHI CHEMICAL), hydrogenated bisphenol A type epoxy resins such as YX-8000 (manufactured by MITSUBISHI CHEMICAL), and YX6954BH30 (manufactured by MITSUBISHI CHEMICAL). Epoxy resins containing a biphenyl backbone, such as CHEMICAL (manufactured by CHEMICAL Corporation); phenol-formaldehyde varnish-type epoxy resins, such as EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.); (ortho-, meta-, and para-)cresol-formaldehyde varnish-type epoxy resins, such as EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.); triglycidyl isocyanurate, such as TEPIC (manufactured by Nissan Chemical Co., Ltd.); alicyclic epoxy resins, such as CELLOXIDE2021P (manufactured by Daicel Corporation); and N,N,N',N'-tetraglycidyl isocyanate. Compounds containing tertiary nitrogen atoms, such as methyl-m-phenylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane or N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane; compounds containing two or more ethylene oxides, such as tetra(glycidyloxymethyl)methane; compounds containing two or more oxobutanes as described in paragraphs 0170 to 0175 of WO2011 / 132751; CORONATE AP stable M, CORONATE 2503, 2515, 2507, 2513, 2555, MILLIONATE MS-50 (and above, manufactured by TOSOH), TAKENATE Compounds with capped isocyanate groups, such as B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, and B-882N (all manufactured by Mitsui Chemicals); compounds with oxazoline groups, such as 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), 2,2'-bis(5-methyl-2-oxazoline), 1,2,4-tris(2-oxazoline)-benzene, and compounds with oxazoline groups, such as EPOCROS (manufactured by Nippon Shokubai Co., Ltd.); compounds with cyclic carbonate groups described in paragraphs 0025 to 0030 and 0032 of WO2011 / 155577.Compounds containing hydroxyl or alkoxy groups, such as N,N,N',N'-tetra(2-hydroxyethyl)hexamethylenediamine, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxyphenyl)propane, and 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane; and compounds containing hydroxyl or alkoxy groups, such as glyceryl mono(meth)acrylate, glyceryl di(meth)acrylate (a mixture of 1,2- and 1,3-types), glyceryl tri(meth)acrylate, glyceryl 1,3-diglyceryl alcohol di(meth)acrylate, pentaerythritol tri(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate, and hexaethylene glycol mono(meth)acrylate.

[0092] The content of the crosslinking compound is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, more preferably 0.1 to 20 parts by mass.

[0093] Examples of compounds used to adjust dielectric constant and resistance include monoamines such as 3-aminomethylpyridine, which have aromatic heterocyclic rings containing nitrogen atoms. The content of the monoamine with the aromatic heterocyclic ring containing nitrogen atoms is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, more preferably 0.1 to 20 parts by mass.

[0094] Preferred specific examples of the aforementioned functional silane compounds include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane. The silanes include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris[3-(trimethoxysilyl)propyl]isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane. The content of the functional silane compound is preferably 0.1 to 30 parts by weight, more preferably 0.1 to 20 parts by weight, relative to 100 parts by weight of the polymer component contained in the liquid crystal alignment agent.

[0095] 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 total mass of the liquid crystal alignment agent) should be appropriately selected considering factors such as viscosity and volatility, and is preferably 1 to 10 by mass.

[0096] 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 1.5 to 4.5% by mass. When using printing, the solid component concentration is particularly preferably 3 to 9% by mass, thereby setting the solution viscosity to 12 to 50 mPa·s. When using inkjet printing, the solid component concentration is particularly preferably 1 to 5% by mass, thereby setting the solution viscosity to 3 to 15 mPa·s. The temperature for preparing the liquid crystal alignment agent is preferably 10 to 50°C, more preferably 20 to 30°C.

[0097] <Liquid crystal alignment film / liquid crystal display element> By using the aforementioned liquid crystal alignment agent, a liquid crystal alignment film can be manufactured. The liquid crystal display element of the present invention includes the aforementioned liquid crystal alignment film. The operating mode of the liquid crystal display element of the present invention is not particularly limited, and it can be applied to various operating modes such as TN mode, STN (Super Twisted Nematic) mode, vertical alignment mode (including VA-MVA (Multi-domain Vertical Alignment) mode, VA-PVA (Patterned Vertical Alignment) mode, IPS mode, FFS mode, and Optically Compensated Birefringence mode (OCB). The liquid crystal alignment film of the present invention is suitable for liquid crystal display elements with horizontal alignment modes such as IPS or FFS mode.

[0098] The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following steps (1) to (3); a method including steps (1) to (4); a method including steps (1) to (3), (3b) and (4); a method including steps (1) to (3), (3a), (3b) and (4); a method including steps (1) to (2) and (4); a method including steps (1) to (3), (4) and (5); or a method including steps (1) to (3), (4) and (6).

[0099] <Step (1): Step of applying liquid crystal alignment agent to at least one of the first substrate and the second substrate> Step (1) is the process of coating the liquid crystal alignment agent of the present invention onto the substrate. A specific example of step (1) is described below.

[0100] 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. As for the substrate, there are no particular limitations as long as it is a highly transparent substrate; it can also be used in conjunction with a glass substrate, a silicon nitride substrate, or a plastic substrate such as an acrylic substrate or a polycarbonate substrate. 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. Moreover, in the manufacture of IPS or FFS type liquid crystal display elements, a substrate having electrodes composed of a patterned comb-shaped transparent conductive film or a metal film and a counter substrate without electrodes are used. The transparent conductive film can be, for example, indium tin oxide (ITO), indium zinc oxide (IZO), or mixtures thereof, formed using known methods.

[0101] Methods for coating a liquid crystal alignment agent onto a substrate to form a film include screen printing, offset printing, flexographic printing, inkjet printing, and spraying. Among these, inkjet printing is preferred.

[0102] <Process (2): The process of firing the coated liquid crystal alignment agent> Step (2) is a process of firing the liquid crystal alignment agent coated on the substrate to form a film. A specific example of step (2) is described below.

[0103] After the liquid crystal alignment agent is coated onto the substrate in step (1), the solvent can be evaporated using a heating unit such as a heating plate, a thermal cycling oven, or an IR (infrared) oven; or thermal imidization of polyamic acid or polyamic acid ester can be performed. The drying and firing steps after coating the liquid crystal alignment agent of the present invention can be performed at any temperature and time, and can be repeated multiple times. As a temperature to reduce the solvent of the liquid crystal alignment agent, it can be performed at, for example, 40 to 180°C. From the viewpoint of shortening the process, it can be performed at 40 to 150°C. As for the firing time, there is no particular limitation, and examples include 1 to 10 minutes or 1 to 5 minutes. In the case of thermal imidization of polyamic acid or polyamic acid ester, a firing step can be added after the above steps, for example, at a temperature range of 150 to 300°C or 150 to 250°C. As for the firing time, there is no particular limitation, and examples include 5 to 40 minutes or 5 to 30 minutes.

[0104] If the film thickness of the fired film is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, it is preferred to be 5 to 300 nm, and more preferably 10 to 200 nm.

[0105] <Step (3): The step of oriented treatment of the film obtained in step (2)> Step (3) is a step of aligning the film obtained in step (2) depending on the situation. That is, in liquid crystal display elements with horizontal alignment such as IPS or FFS, the coating is subjected to an alignment capability imparting treatment. On the other hand, in liquid crystal display elements with vertical alignment such as VA or PSA (Polymer-Sustained Alignment), the formed coating 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. As an alignment treatment method for liquid crystal alignment films, rubbing treatment and photo-alignment treatment can be listed, and photo-alignment treatment is more preferred.

[0106] As a photo-alignment treatment method, the following methods can be listed: irradiating the surface of the above-mentioned film with radiation (more preferably radiation in a polarized state) to impart liquid crystal alignment properties (also known as liquid crystal alignment capability).

[0107] As radiation, ultraviolet light or visible light with wavelengths of 100–800 nm can be used. Among these, ultraviolet light with wavelengths of 100–400 nm is preferred, and ultraviolet light with wavelengths of 200–400 nm is more preferred.

[0108] As an example of the above-mentioned friction treatment method, one can refer to the treatment of rubbing the coating film in a certain direction using a roller made of a cloth made of fibers such as nylon, rayon, or cotton.

[0109] In the above-described optical alignment process, when the radiation is polarized, it can be linearly polarized or partially polarized. Furthermore, when the radiation used is linearly polarized or partially polarized, irradiation can be performed from a direction perpendicular to the substrate surface, from an inclined direction, or a combination of both. When irradiating unpolarized radiation, the irradiation direction is preferably set to an inclined direction.

[0110] The preferred radiation dose is 1–10,000 mJ / cm². 2 More preferably, it is 100–1000 mJ / cm 2 The optimal value is 100–500 mJ / cm. 2 .

[0111] Furthermore, in the above-described photoalignment process, when irradiated with radiation, to improve the alignment of the liquid crystal, the substrate having the film can be heated at 50–250°C while being irradiated. The liquid crystal alignment film produced in this way allows the liquid crystal molecules to be stably aligned in a specific direction.

[0112] The liquid crystal alignment film obtained by the above method can be further subjected to a contact treatment process using a solvent (hereinafter also referred to as process (3a)). The solvent used in the contact treatment of process (3a) is not particularly limited as long as it dissolves the decomposition products generated by irradiation of the film. Specific examples include: water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, etc. Among these, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred from the perspective of versatility and solvent safety. Water, 1-methoxy-2-propanol, or ethyl lactate are more preferred. One solvent may be used, or a combination of two or more may be used.

[0113] The liquid crystal alignment film used in the liquid crystal display element of the present invention can also be manufactured by performing the following process (3b) after the above-described process (3). In addition to performing the alignment process on the film in process (3), process (3b) can also be performed on the film that has undergone the above-described process (3a).

[0114] <Process (3b): Process involving heat treatment> The coating irradiated with the above-mentioned radiation can also be subjected to heat treatment. The temperature of the heat treatment is preferably 50 to 300°C, more preferably 120 to 250°C. The heat treatment time is preferably set to 1 to 30 minutes for each of the above.

[0115] <Step (4): The process of fabricating a liquid crystal cell by disposing a liquid crystal layer adjacent to the film that has undergone the alignment treatment between the first substrate and the second substrate> Step (4) is a step of fabricating a liquid crystal cell by disposing a liquid crystal layer adjacent to the alignment-treated film between the first substrate and the second substrate. It should be noted that the following examples illustrate cases where liquid crystal alignment films are formed on the first substrate and the second substrate, respectively. Specifically, the following two methods can be listed.

[0116] In the first method, two substrates are first arranged opposite each other with their respective liquid crystal alignment films facing each other, separated by a gap (cell gap). Next, the peripheries of the two substrates are bonded together using a sealant, and a liquid crystal composition is injected into the cell gap defined by the substrate surfaces and the sealant. After contact with the film surface, the injection hole is sealed.

[0117] In addition, a second method is known as the ODF (One Drop Fill) method. For example, an ultraviolet-curable resin composition (hereinafter also referred to as a sealant) is applied to a predetermined area on one of two substrates on which a liquid crystal alignment film has been formed. Then, the liquid crystal composition is dropped onto several predetermined locations on the surface of the liquid crystal alignment film. Next, the other substrate is bonded with the liquid crystal alignment film facing each other, and the liquid crystal composition is spread across the entire surface of the substrate, contacting the film surface. Then, the entire surface of the substrate is irradiated with ultraviolet 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.

[0118] It should be noted that when the coating has been rubbed, the two substrates are arranged at a specified angle to each other with the rubbing direction of each coating, for example, in an orthogonal or antiparallel manner.

[0119] As a sealant, epoxy resin containing a curing agent and alumina balls as spacers can be used, for example.

[0120] 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.

[0121] 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, alkyl, alkoxy, alkenyl, isothiocyanate groups, heterocycles, 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 (e.g., bimesocrystalline compounds formed by two rigid biphenyl structures or terphenyl structures linked by alkylene groups).

[0122] The liquid crystal composition can be a nematic liquid crystal composition, a smectic liquid crystal composition, or a cholesteric liquid crystal composition.

[0123] 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.

[0124] Examples of positive liquid crystal displays include: Merck's ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081.

[0125] Examples of negative liquid crystals include MLC-6608, MLC-6609, MLC-6610, and MLC-7026-100 manufactured by Merck.

[0126] In addition, as a liquid crystal containing compounds with polymerizable groups, Merck's MLC-3023 can be cited as an example.

[0127] The liquid crystal alignment agent of the present invention is also preferably used in a liquid crystal display element (PSA type liquid crystal display element) having a liquid crystal layer between a pair of substrates having electrodes and manufactured by the following steps: a liquid crystal composition comprising a polymerizable compound that is polymerized by at least one of active energy rays and heat is disposed between a pair of substrates, a voltage is applied between the electrodes, and the polymerizable compound is polymerized by at least one of active energy ray irradiation and heating (hereinafter, this step is also referred to as step (5)).

[0128] Furthermore, the liquid crystal alignment agent of the present invention is also preferably used in a liquid crystal display element (SC-PVA type liquid crystal display element) having a liquid crystal layer between a pair of substrates having electrodes and manufactured by the following steps: a liquid crystal alignment film containing polymeric groups polymerized by at least one of active energy rays and heat is disposed between the pair of substrates, and a voltage is applied between the electrodes (hereinafter, this step will also be referred to as step (6)).

[0129] 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.

[0130] The IPS substrate, which is a comb electrode substrate used in the IPS method, has: a substrate; a plurality of linear electrodes formed on the substrate and arranged in a comb shape; and a liquid crystal alignment film formed on the substrate to cover the linear electrodes.

[0131] It should be noted that the FFS substrate, which is the comb electrode substrate used in the FFS method, 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 arranged in a comb shape; and a liquid crystal alignment film formed on the insulating film to cover the linear electrodes.

[0132] Figure 1 This is a schematic cross-sectional view illustrating an example of a liquid crystal display element using the lateral electric field method of the present invention, which is an example of an IPS-type liquid crystal display element.

[0133] exist Figure 1 In the liquid crystal display element 1 of the lateral electric field method illustrated in the example, liquid crystal 3 is held between a comb electrode substrate 2 having a liquid crystal alignment film 2c and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb electrode substrate 2 has: a substrate 2a; a plurality of linear electrodes 2b formed on the substrate 2a and arranged in a comb-like configuration; and a liquid crystal alignment film 2c formed on the substrate 2a to cover the linear electrodes 2b. The opposing substrate 4 has: 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.

[0134] In the liquid crystal display element 1 with this lateral electric field mode, 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.

[0135] Figure 2 This is a schematic cross-sectional view illustrating another example of a liquid crystal display element with a lateral electric field mode according to the present invention, which is an example of a liquid crystal display element with an FFS mode.

[0136] exist Figure 2 In the liquid crystal display element 1 of the lateral electric field method illustrated in the example, liquid crystal 3 is sandwiched between a comb electrode substrate 2 having a liquid crystal alignment film 2h and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb electrode substrate 2 has: 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 formed on the insulating film 2f and arranged in a comb-like configuration; and a liquid crystal alignment film 2h formed on the insulating film 2f to cover the linear electrodes 2g. The opposing substrate 4 has: 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, like the liquid crystal alignment film of the present invention.

[0137] 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.

[0138] 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 applied to various other applications, such as liquid crystal alignment films for retardation films; liquid crystal alignment films for scanning antennas and liquid crystal array antennas; or 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).

[0139] 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.

[0140] Example The present invention will be further described in detail below with reference to examples, but the invention is not limited to these examples. The abbreviations of the compounds used and the methods for determining their properties are described below.

[0141] (Organic solvent) THF: Tetrahydrofuran.

[0142] IPA: 2-propanol.

[0143] NMP: N-methyl-2-pyrrolidone.

[0144] BCS: Ethylene glycol monobutyl ether.

[0145] DMAc: Dimethylacetamide.

[0146] (Tetracarboxylic acid dianhydride) CA-1: The compound represented by the following formula (CA-1).

[0147] CA-2: The compound represented by the following formula (CA-2). (Diamine) DA-1 to DA-7: These are compounds represented by the formulas (DA-1) to (DA-7) below.

[0148] Boc: tert-Butoxycarbonyl. The diamines DA-4, DA-5, and DA-6 mentioned above are included in the range of specific diamines (p).

[0149] <Viscosity Measurement> The measurement was performed using a TVE-22H type E viscometer (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL, using a conical rotor TE-1 (1°34', R24), at a temperature of 25°C.

[0150] <Determination of molecular weight> The determination was performed using the following room-temperature GPC (gel permeation chromatography) apparatus, and Mn (number average molecular weight) and Mw (weight average molecular weight) were calculated using the conversion values ​​of polyethylene glycol and polyethylene oxide.

[0151] GPC device: GPC-101 (manufactured by RESONAC (formerly Showa Denko) Co., Ltd.).

[0152] Chromatographic columns: GPC KD-803 and GPC KD-805 (manufactured by RESONAC (formerly Showa Denko) Co., Ltd.) in series.

[0153] Column temperature: 50℃.

[0154] Eluent: N,N-dimethylformamide (as additives, lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, phosphoric acid anhydrous crystals (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L).

[0155] Flow rate: 1.0 mL / min.

[0156] Standard samples used for calibration curve preparation: TSK standard polyethylene oxide (molecular weight; approx. 900,000, approx. 150,000, approx. 100,000 and approx. 30,000) (manufactured by TOSOH) and polyethylene glycol (molecular weight; approx. 12,000, approx. 4,000 and approx. 1,000) (manufactured by Polymer Laboratories).

[0157] [Synthesis of monomers] DA-4, DA-5, and DA-6 are novel compounds not disclosed in the literature. The synthesis methods are described in detail below.

[0158] The products described in the following monomer synthesis examples 1-3 were obtained by... 1 H-NMR analysis was used for identification (analytical conditions are described below).

[0159] Apparatus: Fourier transform superconducting nuclear magnetic resonance (FT-NMR) device "AVANCE III" (BRUKER) 500MHz.

[0160] Solvent: Deuterated dimethyl sulfoxide (DMSO-d6, standard substance: tetramethylsilane).

[0161] (Single synthesis example 1; Synthesis of DA-4) DA-4 is synthesized according to the path shown below. Add 20.0 g (60.2 mmol) of 4,4'-dinitro-[1,1'-biphenyl]-2,2'-dicarboxylic acid, 4-dimethylaminopyridine (DMAP, 1.47 g, 12.0 mmol), and 100 g of THF to a 500 mL four-necked flask to dissolve them, and heat to 70 °C. Using a dropping funnel, slowly add a solution obtained by dissolving di-tert-butyl dicarbonate (Boc₂O, 46.0 g, 210.7 mmol) in THF (15.0 g). After the addition is complete, stir at 70 °C for 2 hours. Concentrate the reaction solution to 50 g, add 120 g of IPA, and stir at 5 °C for 30 minutes to precipitate crystals. The obtained crystals were filtered out, and the filter cake was washed with IPA and then dried under reduced pressure at 40°C to obtain DA-4-1 (yield: 21.0 g, 47.2 mmol, yield: 78%, white crystals).

[0162] The DA-4-1 (20.0 g, 45.0 mmol) obtained above was added to THF (160 g) for nitrogen replacement. Then, carbon-supported palladium (5% by mass Pd carbon powder (50% aqueous content) K type, manufactured by NECHEMCAT) (2.0 g) and activated carbon (specially made White Heron, manufactured by Osaka Gas Chemicals) (2.0 g) were added, and nitrogen replacement was performed again. The mixture was stirred at 50°C for 12 hours under hydrogen pressure (0.3 MPa). After the reaction was completed, the catalyst was filtered and concentrated to 50 g. IPA (240 g) was added, and the mixture was stirred at 5°C for 30 minutes. The precipitated crystals were filtered under reduced pressure, washed with IPA (40 g), and dried under reduced pressure at 40°C to obtain powdered crystals (DA-4) (yield: 14.4 g, 37.5 mmol, yield 83%, white crystals).

[0163] In DMSO-d6 1 H-NMR (500MHz): δ (ppm) = 6.95 (2H, d), 6.74 (2H, d), 6.64-6.67 (2H, dd), 5.18 (4H, s), 1.14 (18H, s).

[0164] (Single synthesis example 2; Synthesis of DA-5) Synthesize DA-5 according to the path shown below. Add 26.6 g (80.0 mmol) of 4,4'-dinitro-[1,1'-biphenyl]-2,2'-dicarboxylic acid, chloromethyl methyl ether (MOMCl, 19.3 g, 240 mmol), and THF (186 g) to a 1 L four-necked flask and dissolve them. Stir at room temperature. Using a dropping funnel, slowly add a solution of N,N-diisopropylethylamine (DIPEA, 31.0 g, 240 mmol) dissolved in THF (80.0 g). After the addition is complete, stir at room temperature for 1 hour. Add 750 g of ethyl acetate to the reaction solution and wash separately with 1 equivalent of hydrochloric acid (260 g) and water (260 g). Concentrate the organic layer to 75 g, add 500 g of methanol, and stir at room temperature for 30 minutes to precipitate crystals. The obtained crystals were filtered out, and the filter cake was washed with methanol (60 g) and then dried under reduced pressure at 40 °C to obtain DA-5-1 (yield: 20.8 g, 49.6 mmol, yield: 62%, white crystals).

[0165] The DA-5-1 obtained above (20.0 g, 47.5 mmol) was added to THF (420 g) for nitrogen replacement, followed by the addition of carbon-supported palladium (5% by mass Pd carbon powder (50% aqueous content) K type, manufactured by NECHEMCAT) (2.0 g), and nitrogen replacement was performed again. A Tedlar bag filled with hydrogen was then installed, and the mixture was stirred at room temperature (23 °C) for 24 hours. After the reaction was complete, the catalyst was filtered and then concentrated to obtain DA-5 (yield: 16.8 g, 46.6 mmol, yield: 98%, yellow oil).

[0166] In DMSO-d6 1 H-NMR (500MHz): δ (ppm) = 7.07 (2H, d), 6.80 (2H, d), 6.69-6.72 (2H, dd), 5.29 (4H, s), 5.09 (4H, s), 3.17 (6H, s).

[0167] (Synthesis Example 3: Synthesis of DA-6) Synthesize DA-6 according to the path shown below. 2-hydroxy-5-nitrobenzene methyl ester (24.8 g, 126.0 mmol), 1,2-bis(tolueneoxyethane) (22.2 g, 60.0 mmol), and DMAc (200 g) were added to a 1 L four-necked flask and dissolved. Potassium carbonate (24.9 g, 180.0 mmol) was then added, and the mixture was stirred at 100 °C for 3 hours. The resulting reaction solution was cooled to room temperature and then added to pure water (870 g). The precipitated crystals were filtered off. The crystals were washed with a filter cake in the order of pure water and methanol, and then dried under reduced pressure to obtain DA-6-1 (yield: 20.6 g, 48.9 mmol, 82%).

[0168] DA-6-1 (15.0 g, 35.8 mmol), methanol (105 g), and DMAc (105 g) were added to a 1 L four-necked flask and dissolved. Then, 2 equivalents of sodium hydroxide aqueous solution (105 g) were added, and the mixture was stirred at 60 °C for 1 hour. After cooling to room temperature, the precipitated salt was filtered off, and the filter cake was washed with methanol. The resulting salt was dissolved in pure water (500 g), and concentrated hydrochloric acid (7.5 g) was added for neutralization. The precipitated crystals were then filtered off. The crystals were washed with pure water and methanol in that order, and then dried under reduced pressure to obtain DA-6-2 (yield 8.8 g, 22.4 mmol, yield: 63%).

[0169] To a 500 mL four-necked flask, DA-6-2 (8.8 g, 22.4 mmol), 4,4'-dimethylaminopyridine (DMAP, 0.54 g, 4.5 mmol), and THF (88 g) obtained above were added and dissolved, and the mixture was heated to 60 °C. Using a dropping funnel, a solution obtained by dissolving di-tert-butyl dicarbonate (Boc₂O, 21.4 g, 98.6 mmol) in THF (20.0 g) was slowly added dropwise. After the addition was complete, the mixture was stirred at 60 °C for 2 hours. The reaction solution was concentrated to 70 g, and IPA (88.0 g) was added. The mixture was stirred at room temperature for 30 minutes to induce crystal precipitation. The resulting crystals were filtered, washed with IPA, and dried under reduced pressure at 40 °C to obtain DA-6-3 (yield: 7.4 g, 14.6 mmol, yield: 66%).

[0170] The DA-6-3 (7.4 g, 14.7 mmol) obtained above was added to THF (110 g) for nitrogen replacement, followed by the addition of carbon-supported palladium (5% by mass Pd carbon powder (50% aqueous content) K type, manufactured by NECHEMCAT) (0.74 g), and nitrogen replacement was performed again. A hydrogen-Tydra sampling bag was then installed, and the mixture was stirred at room temperature (23 °C) for 19 hours. After the reaction was complete, the catalyst was filtered and concentrated to 15 g. IPA (60 g) was added, and the mixture was stirred at room temperature for 30 minutes. The precipitated crystals were filtered under reduced pressure, washed with IPA, and dried under reduced pressure at 40 °C to obtain powdered crystals (DA-6) (yield: 5.4 g, 12.1 mmol, 83% yield, white crystals).

[0171] In DMSO-d6 1 H-NMR (500MHz): 6.85 (2H, d), 6.78 (2H, d), 6.66 (2H, dd), 4.86 (4H, s), 4.11 (4H, s), 1.45 (18H, s).

[0172] [Polymer Synthesis] <Synthesis example 1> DA-1 (1.34 g, 5.5 mmol), DA-3 (1.65 g, 5.5 mmol) (manufactured by Beijing Pure Chem. Co., Ltd.), and NMP (30.30 g) were added to a 50 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 to dissolve the substances. Then, under ice-cold conditions, CA-1 (2.34 g, 10.4 mmol) and NMP (8.86 g) were added, and the mixture was stirred at 40 °C for 12 hours to obtain a 12% by mass solution of polyamic acid (PAA-1) (viscosity: 553 mPa·s). The polyamic acid had a Mn of 12800 and a Mw of 32700.

[0173] <Synthesis example 2> DA-2 (2.00 g, 4.5 mmol), DA-3 (1.35 g, 4.5 mmol), and NMP (30.17 g) were added to a 50 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 to dissolve the substances. Then, under ice-cold conditions, CA-1 (1.94 g, 8.6 mmol) and NMP (8.62 g) were added, and the mixture was stirred at 40 °C for 12 hours to obtain a 12% by mass solution of polyamic acid (PAA-2) (viscosity: 219 mPa·s). The polyamic acid had a Mn of 10150 and a Mw of 23910.

[0174] <Synthesis Example 3> DA-1 (1.47 g, 6.0 mmol), DA-7 (1.63 g, 6.0 mmol), and NMP (31.3 g) were added to a 50 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 (2.47 g, 11.0 mmol) and NMP (9.54 g) were added, and the mixture was stirred at 40 °C for 12 hours, thus obtaining a 12% by mass solution of polyamic acid (PAA-3) (viscosity: 69 mPa·s). The polyamic acid had a Mn of 5500 and a Mw of 10900.

[0175] <Synthesis example 4> DA-1 (1.22 g, 5.0 mmol), DA-4 (1.92 g, 5.0 mmol), and NMP (23.00 g) were added to a 50 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 to dissolve the substances. Then, under ice-cold conditions, CA-1 (2.06 g, 9.2 mmol) and NMP (15.10 g) were added, and the mixture was stirred at 40 °C for 12 hours to obtain a 12% by mass solution of polyamic acid (PAA-4) (viscosity: 383 mPa·s). The Mn of this polyamic acid was 16100, and the Mw was 36700.

[0176] <Synthesis example 5> DA-1 (1.53 g, 6.3 mmol), DA-5 (2.25 g, 6.2 mmol), and NMP (38.20 g) were added to a 50 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 to dissolve the substances. Then, under ice-cold conditions, CA-1 (2.63 g, 11.7 mmol) and NMP (8.82 g) were added, and the mixture was stirred at 40 °C for 12 hours to obtain a 12% by mass solution of polyamic acid (PAA-5) (viscosity: 472 mPa·s). The Mn of this polyamic acid was 14620, and the Mw was 37850.

[0177] <Synthesis Example 6> DA-1 (1.10 g, 4.5 mmol), DA-6 (2.00 g, 4.5 mmol), and NMP (27.90 g) were added to a 50 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 to dissolve the substances. Then, under ice-cold conditions, CA-1 (1.91 g, 8.5 mmol) and NMP (8.82 g) were added, and the mixture was stirred at 40 °C for 12 hours to obtain a 12% by mass solution of polyamic acid (PAA-6) (viscosity: 310 mPa·s). The Mn of this polyamic acid was 15144, and the Mw was 31580.

[0178] <Synthesis Example 7> DA-6 (4.01 g, 9.0 mmol) and NMP (36.01 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. Then, under ice-cold conditions, CA-1 (1.94 g, 8.6 mmol) and NMP (7.54 g) were added, and the mixture was stirred at 40 °C for 12 hours to obtain a 12% by mass solution of polyamic acid (PAA-7) (viscosity: 145 mPa·s). The polyamic acid had a Mn of 10900 and a Mw of 26800.

[0179] <Synthesis example 8> DA-2 (2.00 g, 4.5 mmol), DA-4 (1.73 g, 4.5 mmol), and NMP (33.58 g) were added to a 50 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 (1.94 g, 8.6 mmol) and NMP (7.99 g) were added, and the mixture was stirred at 40 °C for 12 hours, thus obtaining a 12% by mass solution of polyamic acid (PAA-8) (viscosity: 285 mPa·s). The polyamic acid had a Mn of 12680 and a Mw of 31130.

[0180] <Synthesis Example 9> DA-1 (1.10 g, 4.5 mmol), DA-4 (1.73 g, 4.5 mmol), and NMP (25.47 g) were added to a 50 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 to dissolve the substances. Then, under ice-cold conditions, CA-2 (1.83 g, 8.4 mmol) and NMP (8.53 g) were added, and the mixture was stirred at 40 °C for 12 hours to obtain a 12% by mass solution of polyamic acid (PAA-9) (viscosity: 389 mPa·s). The Mn of this polyamic acid was 15020, and the Mw was 34190.

[0181] The specifications of the polyamic acids obtained in the above synthesis examples are shown in Table 1. In Table 1, the values ​​in parentheses for the diamine components indicate the amount (mole parts) of each compound used relative to the total amount (100 moles) of the diamine components used in each polymerization step. The values ​​in parentheses for the tetracarboxylic acid components indicate the amount (mole parts) of each compound used relative to the total amount (100 moles) of the tetracarboxylic acid components used in each polymerization step. [Preparation of liquid crystal alignment agent] <Comparative Example 1> A solution of polyamic acid (PAA-1) obtained in Synthesis Example 1 (10.0 g), NMP (6.0 g), and BCS (4.0 g) was added to a sample tube containing a stir bar. The mixture was stirred at 23°C for 30 minutes to obtain a liquid crystal alignment agent (AL-R1) with a polymer solid component to each solvent mass ratio (polymer solid component: NMP: BCS) of 6:74:20.

[0182] <Comparative Example 2, Reference Example 1, Examples 1-6> As shown in Table 2, the type of polyamic acid solution used was changed, and the same method as in Comparative Example 1 was used to obtain liquid crystal alignment agents (AL-R2), (AL-R3), and (AL-1) to (AL-6), respectively. In Table 2, the values ​​in parentheses indicate the proportion (parts by mass) of each polymer component relative to 100 parts by mass of the total polymer component used to prepare the liquid crystal alignment agent for polymers. For organic solvents, the proportion (parts by mass) of each organic solvent relative to 100 parts by mass of the liquid crystal alignment agent is indicated. [Evaluation Example 1: Evaluation of Sealing and Tightness] <Comparative Examples 1-2, Examples 1-6> Using the liquid crystal alignment agents (AL-R1) to (AL-R2) and (AL-1) to (AL-6) obtained in Comparative Examples 1-2 and Examples 1-6 above, liquid crystal alignment agents were coated onto a 30mm × 40mm ITO substrate using a spin coater. Next, after drying on a heated plate at 80°C for 2 minutes, the substrate was fired in an IR oven at 230°C for 30 minutes to form a coating film with a thickness of 100nm. Further, the coating surface was subjected to a polarizing test with a polarizing plate at 50mJ / cm². 2 The substrate was irradiated with linearly polarized ultraviolet light of 254 nm with an extinction ratio of 26:1. Finally, it was fired in an IR oven at 230 °C for 30 minutes to obtain a substrate with a liquid crystal alignment film.

[0183] Prepare two substrates with liquid crystal alignment films obtained in this way. After coating 4μm bead-shaped spacers on the liquid crystal alignment film surface of one substrate, add a sealant (manufactured by Kyoritsu Chemical Industry Co., Ltd., product number 7142T). Then, with the liquid crystal alignment film surface of the other substrate as the inner side, the substrates are bonded together with an overlap width of 1cm. Figure 3 (A schematic diagram is shown below). At this point, adjust the sealant application rate so that the diameter of the sealant after bonding is 3 mm. The two substrates are then secured with clamps. Apply 3.0 J / cm² to the substrate. 2 Irradiate with ultraviolet light of wavelength 365nm to light-cur the seal, and then heat-cur the seal at 120°C for 1 hour.

[0184] The substrate peel test was performed using a small benchtop testing machine, Shimadzu EZ-SX. After fixing the ends of the upper and lower substrates, the center of the substrate was pressed down from above, and the force (N) during peeling was measured. As an evaluation criterion, a peel strength value of 10N or more was designated as "good," and a peel strength value less than 10N was designated as "poor." The results are shown in Table 3. Liquid crystal alignment films obtained using liquid crystal alignment agents with specific diamines exhibit better adhesion to sealants compared to those obtained using liquid crystal alignment agents without specific diamines. This is presumably because the protecting groups in the specific diamine detach during firing, generating carboxyl groups, thus improving the adhesion between the sealant and the liquid crystal alignment film.

[0185] [Fabrication of FFS-driven LCD cell] <Examples 1-5, Reference Example 1> A liquid crystal cell with an FFS mode liquid crystal display element was manufactured.

[0186] First, a substrate with electrodes is prepared. The substrate is a rectangular glass substrate measuring 30mm × 35mm with a thickness of 0.7mm. An ITO electrode with a dense pattern, constituting a common electrode, is formed on the substrate as the first layer. A SiN (silicon nitride) film, deposited by CVD (chemical vapor deposition), is formed on the common electrode of the first layer as the second layer. The SiN film of the second layer has a thickness of 300nm, which functions as an interlayer insulating film. A comb-shaped pixel electrode, formed by patterning the ITO film, is disposed on the SiN film of the second layer as the third layer, forming two types of pixels: a first pixel and a second pixel. Each pixel has dimensions of 10mm in length and 5mm in width. This substrate with electrodes has a structure where the common electrode of the first layer and the pixel electrode of the third layer are insulated by the SiN film of the second layer.

[0187] The third layer of pixel electrodes has a comb-like shape formed by multiple electrode lines arranged in parallel at 6μm intervals, with the central part bent at an inner angle of 160°. Each pixel is formed by multiple electrode lines, and has a first region and a second region with the line connecting the bent part as the boundary.

[0188] Next, the liquid crystal alignment agents (AL-R3) and (AL-1) to (AL-5) obtained in Reference Example 1 and Examples 1 to 5 were filtered using a 1.0 μm pore size filter and then coated onto the electrode substrate (hereinafter referred to as the electrode substrate) and a glass substrate with an ITO film on the back side and columnar spacers with a height of 4 μm (hereinafter referred to as the opposing substrate) by spin coating. After drying on a heating plate at 80°C for 2 minutes, the coating was fired in an IR oven at 230°C for 30 minutes to form a coating film with a thickness of 100 nm. The coating surface was subjected to a 600 mJ / cm² pressure. 2 The substrate was irradiated with 254nm polarized ultraviolet light that had passed through a 240nm low-cutoff filter and a polarizer, and then fired in an IR oven at 230°C for 30 minutes to perform an alignment process, resulting in a substrate with a liquid crystal alignment film. It should be noted that, for the liquid crystal alignment film formed on the electrode substrate, the alignment process was performed such that the direction dividing the inner angle of the pixel bend was orthogonal to the alignment direction of the liquid crystal; for the liquid crystal alignment film formed on the opposing substrate, the alignment process was performed such that the alignment direction of the liquid crystal on the electrode substrate was consistent with the alignment direction of the liquid crystal on the opposing substrate during the fabrication of the liquid crystal cell. Using the two substrates as a group, a sealant (Mitsui Chemicals XN-1500T) was printed onto the substrates using a dispensing machine, and the other substrate was bonded together with the alignment directions of their respective liquid crystal alignment films at 0° and facing each other. Then, the bonded substrates were pressed together and heated in a hot air circulating oven at 150°C for 60 minutes to cure the sealant, producing an empty cell. Positive liquid crystal MLC-3019 (manufactured by Merck) was injected into the empty cell using a depressurized injection method, and the injection port was sealed, thus obtaining an FFS-driven liquid crystal cell. The obtained FFS-driven liquid crystal cell was then heated at 120°C for 1 hour and placed at 23°C overnight for evaluation.

[0189] [Evaluation Example 2: Evaluation of the in-plane uniformity of liquid crystal alignment constraint force] <Examples 1-5, Reference Example 1> By visually observing the FFS-driven liquid crystal cells obtained using the liquid crystal alignment agents (AL-1) to (AL-5) of Examples 1 to 5 above, it was confirmed that there was no disorder in the liquid crystal alignment and that the alignment was uniform in the plane.

[0190] Furthermore, the non-uniformity of the torsion angle of the FFS-driven liquid crystal cells obtained in Reference Example 1 and Example 1 was evaluated using a polarization / phase difference resolution system (AxoStep, manufactured by AXOMETRICS). The liquid crystal cells fabricated above were placed on a measurement stage, and the distribution of circular retardance within the pixel plane was measured without applied voltage. Three times the standard deviation σ, i.e., 3σ, was calculated. It can be said that the smaller the value of 3σ, the better the in-plane uniformity of the orientation constraint force. The results are shown in Table 4. The liquid crystal alignment film obtained using a liquid crystal alignment agent (AL-1) with a carboxyl-protected diamine (DA-4) exhibits less non-uniformity in twist angle compared to the liquid crystal alignment film obtained using a liquid crystal alignment agent (AL-R3) with an unprotected carboxyl-protected diamine (DA-7). From the perspective of improving the alignment uniformity of liquid crystals, it is effective to protect the carboxyl groups present within the diamine molecule using a protecting group that is thermally detached.

[0191] Industrial availability By using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film with high in-plane uniformity of liquid crystal alignment constraint force and high adhesion to the sealant can be obtained. Therefore, its application in liquid crystal display elements requiring high display quality and large display area is expected, especially in liquid crystal display elements using IPS driving method and FFS driving method. Furthermore, these elements are also useful in liquid crystal displays for display purposes, dimming windows for controlling light transmission and blocking, optical shutters, etc.

[0192] Explanation of reference numerals in the attached figures 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.

[0193] It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2023-194652, filed on November 15, 2023, are incorporated herein as a disclosure of the specification of this invention.

Claims

1. A liquid crystal alignment agent comprising a polymer P, wherein the polymer P is at least one selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic acid component and a diamine component, and a polyimide of an imide derivative thereof as the polyimide precursor, wherein the tetracarboxylic acid component comprises at least one selected from the group consisting of tetracarboxylic dianhydrides and their derivatives, and the diamine component comprises a diamine represented by the following formula (2). In equation (2), R 21 ~R 24 Independently representing hydrogen atoms or *-CO2R, R 21 ~R 24 At least two of them represent *-CO2R; R represents a protecting group D0 that is replaced by a hydrogen atom by heat; one or more hydrogen atoms on the benzene ring bonded to the amino group are optionally replaced by a monovalent group other than *-CO2R; L represents a single bond or a divalent linking group; * represents a bonded bond.

2. The liquid crystal alignment agent according to claim 1, wherein, The content of the diamine shown in formula (2) is more than 5 mol% relative to 1 mole of the diamine component used to manufacture polymer P.

3. The liquid crystal alignment agent according to claim 1, wherein, The protective base D0 is a structure selected from the group consisting of the following formulas (a-1) to (a-6). In equation (a-2), R 2a R 2b Each independently represents an alkyl group having 1 to 3 hydrogen atoms or carbon atoms; R 2c * indicates an alkyl group with 1 to 5 carbon atoms; * indicates a bonded bond.

4. The liquid crystal alignment agent according to claim 1, wherein, The divalent linking group is -CH2-, -O-, -O-C(=O)-, -C(=O)-, -N(R)-, -N(R)-C(=O)-N(R)-, cyclohexene, or an alkylene group having 2 to 18 carbon atoms. In -N(R)-, R represents a hydrogen atom, a methyl group, or a Boc atom. In -N(R)-C(=O)-N(R)-, R represents a hydrogen atom, a methyl group, or a Boc atom, and the two R groups may optionally be the same or different. In the alkylene group having 2 to 18 carbon atoms, any - CH2- is optionally substituted with -O-, -O-C(=O)-, -C(=O)-, -N(R)-, -N(R)-C(=O)-, cyclohexene, or phenylene, wherein the oxygen atoms are not adjacent to each other, and in the -N(R)-, R represents a hydrogen atom, a methyl group, or a Boc; in the -N(R)-C(=O)-, R represents a hydrogen atom, a methyl group, or a Boc; furthermore, any hydrogen atom on the cyclohexene or phenylene group is optionally substituted with a halogen atom or an alkyl or alkoxy group having 1 to 5 carbon atoms.

5. The liquid crystal alignment agent according to claim 1, wherein, The diamine represented by formula (2) is any of the diamines represented by formulas (2-1) to (2-4) below. In the formula, t-Bu represents tert-butyl.

6. The liquid crystal alignment agent according to claim 1, wherein, The tetracarboxylic dianhydride and its derivatives are selected from noncyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, or their derivatives.

7. The liquid crystal alignment agent according to claim 6, wherein, The content of acyclic aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, or their derivatives is 10 mol% or more relative to 1 mole of the tetracarboxylic acid component used to manufacture polymer P.

8. The liquid crystal alignment agent according to claim 1, wherein, The diamine component further contains other diamines, which are selected from phenylenediamine, diaminobiphenyl compounds, and compounds of the following formula (d AL The diamine is at least one of the following groups: a diamine having a diphenyl ether structure, a diamine having a tetracarboxylic acid diimide structure, a diamine having an amide bond, a diamine having a urea bond, and a diamine having a "-N(D)-" group, wherein in the "-N(D)-" group, D represents a protecting group that is thermally removed and substituted with a hydrogen atom. In the formula, Ar1 and Ar 1’ Each represents a benzene ring, a biphenyl structure, or a naphthalene ring, wherein one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring are optionally unsubstituted or substituted with monovalent groups; L1 and L 1’ Each represents a single bond, -O-, -C(=O)-, or -O-C(=O)-; A represents -CH2-, an alkylene group with 2 to 12 carbon atoms, or a divalent organic group formed by inserting at least any group from -O-, -C(=O)-O-, and -O-C(=O)- between the carbon-carbon bonds of the alkylene group.

9. The liquid crystal alignment agent according to claim 1, wherein, The liquid crystal alignment agent further contains other polymers besides polymer P.

10. A liquid crystal alignment film obtained from a liquid crystal alignment agent as described in any one of claims 1 to 9.

11. A liquid crystal display element comprising a liquid crystal alignment film as claimed in claim 10.

12. A method for manufacturing a liquid crystal display element, wherein, Including the following processes 1 to 4, Step 1: The step of coating a liquid crystal alignment agent as described in any one of claims 1 to 9 onto at least one of a first substrate and a second substrate; Step 2: The process of firing the coated liquid crystal alignment agent to obtain a film; Step 3: The step of oriented processing of the film obtained in Step 2; Step 4: A step of fabricating a liquid crystal cell by disposing a liquid crystal layer adjacent to the film that has undergone the alignment treatment between the first substrate and the second substrate.

13. The method for manufacturing a liquid crystal display element according to claim 12, wherein, The orientation process is a photo-orientation process.

14. The method for manufacturing a liquid crystal display element according to claim 13, wherein, Between process 3 and process 4, there is a further step: process 3b, which involves heat treatment.

15. The method for manufacturing a liquid crystal display element according to claim 14, wherein, The liquid crystal display element is an IPS or FFS type liquid crystal display element.

16. A diamine, wherein, The diamine is represented by any of the following formulas (2-1) to (2-4). In the formula, t-Bu represents tert-butyl.

17. The diamine according to claim 16, wherein, The diamine is represented by any of the following formulas (2-1) to (2-3). In the formula, t-Bu represents tert-butyl.

Images