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

Abstract

The present application relates to a liquid crystal alignment agent containing a polymer (A) which is at least one selected from the group consisting of a polyimide precursor having a repeating unit (al) represented by the following formula (1) and a polyimide which is an imidized product of the polyimide precursor. (At least one of R1 to R4 is a group other than a hydrogen atom, for example, an alkyl group having 1 to 6 carbon atoms.) (R a1 ~R a3 For example, a monovalent organic group having 1 to 3 carbon atoms. L1 represents, for example, 1-O-C(=O)-2. L2 represents, for example, 2-C(=O)-O-3. al to a3 satisfy al+a2+a3≥1.

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] Previously, liquid crystal displays (LCDs) were widely used as display units in personal computers, smartphones, mobile phones, television receivers, and the like. An LCD typically includes: a liquid crystal layer sandwiched between a component 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 switches the electrical signals supplied to the pixel electrodes. 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] Currently, the most widely used liquid crystal alignment film in industry is manufactured by brushing 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. Brushing is a simple and highly productive method useful in industry. However, with the increasing performance, resolution, and size of liquid crystal display elements, various problems have become apparent during brushing, such as damage to the alignment film surface, dust generation, mechanical stress, effects caused by static electricity, and inhomogeneities within the alignment surface. As an alternative to brushing, photoalignment, which imparts alignment energy to the liquid crystal by irradiating it with polarized radiation, is known. Regarding photoalignment, methods utilizing photoisomerization reactions, photocrosslinking reactions, and photodecomposition reactions have been proposed (see, for example, Non-Patent Literature 1, Patent Literature 1, and Patent Literature 2).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 9-297313

[0007] Patent Document 2: WO2016 / 152928

[0008] Non-patent literature

[0009] Non-Patent Literature 1: "Liquid Crystal Optical Alignment Film" by Kido Waki ​​and Ichimura Functional Materials, November 1997, Vol. 17, No. 1113-22 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] For liquid crystal alignment films used in IPS and FFS driving liquid crystal display elements, a high alignment constraint force is required to suppress image retention (hereinafter also referred to as AC image retention) caused by long-term AC driving. Furthermore, when performing alignment processing using photo-alignment, the amount of light irradiation is a factor affecting energy consumption and production speed, so it is preferable to perform alignment processing with a low amount of light irradiation.

[0012] However, the inventors conducted research and determined that, for liquid crystal alignment films that can achieve liquid crystal alignment with low light irradiation and suppress AC image retention, the polymer components used are sensitive to light irradiation, resulting in a narrow range of light irradiation required to obtain a liquid crystal alignment film that suppresses AC image retention. Therefore, when pursuing larger screen sizes for liquid crystal display elements, the liquid crystal alignment becomes incomplete in a portion of the obtained liquid crystal alignment film. During prolonged image display, in-plane brightness deviations may occur, reducing the display quality level.

[0013] Therefore, the object of the present invention is to provide a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film, wherein the liquid crystal alignment agent can expand the range of light irradiation amount for obtaining a liquid crystal alignment film that can suppress AC image retention, and efficiently obtain a liquid crystal alignment film of good quality.

[0014] Solution for solving the problem

[0015] The inventors conducted in-depth research and discovered that by using a liquid crystal alignment agent containing specific components, the above-mentioned problems can be solved, thus completing this invention. Specifically, the following is the main content.

[0016] A liquid crystal alignment agent, characterized in that it contains a polymer (A), which is at least one selected from the group consisting of a polyimide precursor having a repeating unit (a1) as shown in the following formula (1) and a polyimide as an imide derivative of the polyimide precursor.

[0017]

[0018] (In formula (1), R1 to R4 each 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 with 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. At least one of R1 to R4 represents a group other than a hydrogen atom as defined above. R and Z each independently represent a hydrogen atom or an alkyl group with 1 to 6 carbon atoms. Y1 represents a divalent organic group as shown in formula (H) below.)

[0019]

[0020] (In formula (H), R) a1 ~R a3 Each can independently represent a hydroxyl group, a halogen atom, or a monovalent organic group having 1 to 3 carbon atoms. Furthermore, the presence of multiple R groups... a1 ~R a3 In this case, they may be optionally the same or different. L1 represents *1-O-C(=O)-*2 or *1-C(=O)-O-*2. Wherein, *1 and optionally have substituent R... a1 The benzene ring is bonded, *2 with R which optionally has a substituent. a2 The benzene ring is bonded. L2 represents *2-O-C(=O)-*3 or *2-C(=O)-O-*3. Wherein, *2 is bonded to an optional substituent R. a2 The benzene ring is bonded, *3 with optional substituent R a3 The benzene ring is bonded. a1 to a3 are each independent integers from 0 to 4, and satisfy a1 + a2 + a3 ≥ 1. * indicates a bond.

[0021] It should be noted that in this specification, * denotes a bond in all cases. Examples of halogen atoms include: fluorine, chlorine, bromine, and iodine.

[0022] Invention Effects

[0023] According to the present invention, a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film can be provided. The liquid crystal alignment agent can expand the range of light irradiation amount for obtaining a liquid crystal alignment film that can suppress AC image retention, and efficiently obtain a liquid crystal alignment film of good quality. Attached Figure Description

[0024] Figure 1 This is a schematic cross-sectional view illustrating an example of a transverse electric field liquid crystal display element of the present invention.

[0025] Figure 2 This is a schematic cross-sectional view showing another example of the transverse electric field liquid crystal display element of the present invention. Detailed Implementation

[0026] <Polymer (A)>

[0027] The liquid crystal alignment agent of the present invention contains a polymer (A), which is selected from at least one group consisting of a polyimide precursor having a repeating unit (a1) as shown in the following formula (1) and a polyimide as an imide derivative of the polyimide precursor.

[0028]

[0029] (In formula (1), R1 to R4 each 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 with 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. At least one of R1 to R4 represents a group other than hydrogen atoms as defined above. R and Z each independently represent a hydrogen atom or an alkyl group with 1 to 6 carbon atoms. Y1 represents a divalent organic group as shown in formula (H) below.) It should be noted that the groups other than hydrogen atoms as defined above refer to halogen atoms, alkyl groups with 1 to 6 carbon atoms, alkenyl groups with 2 to 6 carbon atoms, alkynyl groups with 2 to 6 carbon atoms, monovalent organic groups with 1 to 6 carbon atoms containing a fluorine atom, and phenyl groups.

[0030]

[0031] (In formula (H), R) a1 ~R a3 Each can independently represent a hydroxyl group, a halogen atom, or a monovalent organic group having 1 to 3 carbon atoms. Furthermore, the presence of multiple R groups... a1 ~R a3 In this case, they may be optionally the same or different. L1 represents *1-O-C(=O)-*2 or *1-C(=O)-O-*2. Wherein, *1 and optionally have substituent R... a1 The benzene ring is bonded, *2 with R which optionally has a substituent. a2 The benzene ring is bonded. L2 represents *2-O-C(=O)-*3 or *2-C(=O)-O-*3. Wherein, *2 is bonded to an optional substituent R. a2 The benzene ring is bonded, *3 with optional substituent R a3 The benzene ring is bonded. a1 to a3 are each independent integers from 0 to 4, and satisfy a1 + a2 + a3 ≥ 1. * indicates a bond.

[0032] From the viewpoint of efficiently obtaining the effects of the present invention, the divalent organic group represented by the above formula (H) is preferably the divalent organic group represented by the following formula (H').

[0033]

[0034] (R a1 ~R a3 L1, L2, and a1 to a3 have the same meaning as in equation (H) above. * indicates a bond.

[0035] Specific examples of alkyl groups having 1 to 6 carbon atoms in R1 to R4 include: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, etc. Specific examples of alkenyl groups having 2 to 6 carbon atoms in R1 to R4 include: vinyl, propenyl, butynyl, etc., which may optionally be linear or branched. Specific examples of alkynyl groups having 2 to 6 carbon atoms in R1 to R4 include, for example: ethynyl, 1-propynyl, 2-propynyl, etc. Specific examples of monovalent organic groups having 1 to 6 carbon atoms containing fluorine atoms in R1 to R4 include: fluoromethyl, trifluoromethyl, pentafluoroethyl, pentafluoropropyl, etc. Regarding more preferred combinations of R1 to R4, from the viewpoint of high photoreactivity, R1 to R4 are either hydrogen atoms or methyl groups; preferably, at least one of R1 to R4 is methyl, and more preferably, at least two of R1 to R4 are methyl groups. Further preferred cases are those where R1 and R4 are methyl groups and R2 and R3 are hydrogen atoms.

[0036] Examples of monovalent organic groups in formula (H) above include: alkyl groups with 1 to 3 carbon atoms, haloalkyl groups formed by replacing at least a portion of the hydrogen atoms on alkyl groups with halogen atoms, alkoxy groups with 1 to 3 carbon atoms, haloalkoxy groups formed by replacing at least a portion of the hydrogen atoms on alkoxy groups with halogen atoms, and alkenyl groups with 2 to 3 carbon atoms. Examples of alkyl groups with 1 to 3 carbon atoms include the structures exemplified in R1 to R4 above. Examples of haloalkyl groups include: fluoromethyl, trifluoromethyl, pentafluoroethyl, pentafluoropropyl, etc. Among these, methyl or methoxy groups are preferred as monovalent organic groups.

[0037] From the viewpoint of efficiently obtaining the effects of the present invention, the divalent organic group represented by the above formula (H) is preferably any of the following formulas (h-1) to (h-14) as the divalent organic group.

[0038]

[0039]

[0040] From the viewpoint of efficiently obtaining the effects of the present invention, the polymer (A) described above may also be at least one polymer selected from the group consisting of a polyimide precursor having a repeating unit (a2) shown in formula (2) and a polyimide as an imide derivative of the polyimide precursor. That is, polymer (A) may also be at least one polymer selected from the group consisting of a polyimide precursor having a repeating unit (a1) shown in formula (1) and a repeating unit (a2) shown in formula (2) and a polyimide as an imide derivative of the polyimide precursor.

[0041]

[0042] (In formula (2), R1 to R4, R, and Z have the same meaning as in formula (1) above. Y2 represents the divalent organic group shown in formula (O) below.)

[0043] *——Ar——Q2——Ar——* (O)

[0044] In formula (O), each Ar independently represents a benzene ring, a biphenyl structure, or a naphthalene ring. Any hydrogen atom on the benzene or naphthalene ring of Ar may optionally be replaced by a halogen atom or a monovalent organic group. Q2 represents –(CH2). n - (n is an integer from 2 to 18), or the above - (CH2) n A group formed by replacing a portion of a component with any one of -O-, -C(=O)-, and -O-C(=O)-.

[0045] In the above formula (O), any hydrogen atom on the benzene ring or naphthalene ring of Ar is optionally replaced by a halogen atom or a monovalent organic group (e.g., 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 with 1 to 6 carbon atoms containing a fluorine atom, etc.). Specific examples of these monovalent organic groups are the structures illustrated in R1 to R4 above.

[0046] From the viewpoint of improving liquid crystal orientation, the divalent organic group represented by any of the following formulas (o-1) to (o-14) is preferred as the divalent organic group shown in formula (o-1) to (o-14). It should be noted that in formulas (o-1) to (o-14), n is more preferably 2 to 4, and even more preferably 2 or 4. In formula (o-10), m is preferably 2. In (o-14), m is more preferably 0 or 2.

[0047]

[0048] (In equation (o-14), the two m's are independent.)

[0049] From the viewpoint of efficiently obtaining the effects of the present invention, the polymer (A) described above may be at least one polymer selected from the group consisting of a polyimide precursor and a polyimide as an imide derivative of the polyimide precursor, wherein the polyimide precursor further has at least one selected from the group consisting of a repeating unit (a2') shown in formula (2') and a repeating unit (a3) ​​shown in formula (3). That is, polymer (A) may be at least one polymer selected from the group consisting of a polyimide precursor and a polyimide as an imide derivative of the polyimide precursor, wherein the polyimide precursor has at least one repeating unit (a1) shown in formula (1) and a repeating unit (a2') shown in formula (2') and a repeating unit (a3) ​​shown in formula (3).

[0050]

[0051] In equations (2') and (3), X 2’ X3 represents a tetravalent organic group, Y 2’ Y2 represents the divalent organic group shown in the following formula (O2), and Y3 represents a divalent organic group with 6 to 30 carbon atoms other than D, containing the group "-N(D)-" (D represents a carbamate protecting group). R and Z have the same meaning as in formula (1) above.

[0052]

[0053] (In formula (O2), Ar) 2’ Each element independently represents a benzene ring, wherein any hydrogen atom on the benzene ring is optionally replaced by a halogen atom, an alkyl group having 1 to 3 carbon atoms, or a haloalkyl group having 1 to 3 carbon atoms. Q 2’ Indicates a single bond or -O-. m represents an integer from 0 to 2.

[0054] From the viewpoint of minimizing the generation of AC residuals, divalent organic groups represented by the above formula (O2) are preferred as divalent organic groups represented by any of the following formulas (o2-1) to (o2-12).

[0055]

[0056] The D in Y3 above represents a urethane-based protecting group. Examples of urethane-based protecting groups include tert-butoxycarbonyl or 9-fluorenylmethoxycarbonyl.

[0057] As a specific example of Y3 mentioned above, divalent organic groups represented by the following formula (Dx) can be listed.

[0058]

[0059] In the formula, Q5 is a single bond; -(CH2) n -(n is an integer from 1 to 20); or -(CH2) n Any -CH2- can be replaced by -O-, -COO-, -OCO-, -NQ9-, -NQ9CO-, -CONQ9-, -NQ9-CO-NQ 10 A group formed by substituting -, -NQ9-COO- or -OCOO-, Q9 and Q 10 Each of the groups independently represents a hydrogen atom or a monovalent organic group; Q6 and Q7 each independently represent -H, a group having -NHD (preferably -NHD), or a group having -N(D)2 (preferably -N(D)2). Wherein, when m=0, Q6 has a urethane-based protecting group; when m=1, at least one of Q5, Q6, and Q7 has a urethane-based protecting group in its group. Furthermore, in Q6 and Q7, when representing groups other than hydrogen atoms, the preferred number of carbon atoms is 1 to 8.

[0060] As mentioned above, Q9 and Q 10 Monovalent organic groups can be listed as: alkyl groups with 1 to 6 carbon atoms, alkenyl groups with 2 to 6 carbon atoms, alkynyl groups with 2 to 6 carbon atoms, and monovalent organic groups with 1 to 6 carbon atoms containing fluorine atoms. As specific examples, the structures shown in R1 to R4 above can be listed.

[0061] As a preferred specific example of Y3, from the viewpoint of having fewer AC residuals, any of the following formulas (Y3-1) to (Y3-5) can be listed as divalent organic groups. “Boc” represents tert-butoxycarbonyl.

[0062]

[0063] As X 2’ In addition to the tetravalent organic groups shown in formula (g) below, X3 can also include: tetravalent organic groups shown in any of the formulas (X-1) to (X-25) below, tetravalent organic groups derived from aromatic tetracarboxylic acid dianhydrides, etc. From the viewpoint of efficiently obtaining the effects of the present invention, X 2’ X3 is more preferably a tetravalent organic group as shown in the following formula (g).

[0064]

[0065] (R1, R2, R3, and R4 have the same meaning as R1, R2, R3, and R4 in equation (1) above. * indicates a bond.)

[0066]

[0067] Aromatic tetracarboxylic acid dianhydrides refer to acid dianhydrides obtained by intramolecular dehydration of carboxyl groups bonded to aromatic rings such as benzene and naphthalene rings. Specific examples of tetravalent organic groups derived from aromatic tetracarboxylic acid dianhydrides include: tetravalent organic groups represented by any of the following formulas (Xa-1) to (Xa-2), and tetravalent organic groups represented by any of the following formulas (Xr-1) to (Xr-7).

[0068]

[0069] (x and y are each independently a single bond, ether bond, carbonyl group, ester bond, alkylene group with 1 to 10 carbon atoms, 1,4-phenylene group, sulfonyl group, or amide group. j and k are integers of 0 or 1.)

[0070]

[0071] The tetravalent organic group shown in formula (Xa-1) or (Xa-2) above can also be any of the structures shown in formulas (Xa-3) to (Xa-19) below.

[0072]

[0073] The polymer (A) described above may be at least one polymer selected from the group consisting of a polyimide precursor having a repeating unit (a4) as shown in the following formula (4) in addition to having the repeating unit (a1), repeating unit (a2), repeating unit (a2'), and repeating unit (a3) ​​described above, and a polyimide as an imide derivative of the polyimide precursor.

[0074]

[0075] In the formula, X4 represents a tetravalent organic group, and Y4 represents a divalent organic group. R and Z have the same meaning as R and Z in the above formula (1). Among them, Y4 represents a divalent organic group with 6 to 30 carbon atoms other than D, except for the group "-N(D)- (D represents a carbamate protecting group)" in the molecule, and a structure other than the divalent organic group shown in the above formula (O2). Furthermore, when X4 has the same meaning as the tetravalent organic group shown in the above formula (g), Y4 represents a structure other than the divalent organic group shown in the above formula (H) and the divalent organic group shown in the above formula (O). As a specific example of X4, X can be listed. 2’ The structure illustrated in X3.

[0076] As a specific example of X4, the above X can be listed. 2’The example shown is a tetravalent organic group. From the viewpoint of efficiently obtaining the effects of the present invention, X4 is more preferably a tetravalent organic group shown in formula (g) above, or a tetravalent organic group shown in any of the formulas (X-1) to (X-25) above, and even more preferably a tetravalent organic group shown in formula (g) above.

[0077] Specific examples of divalent organic groups of Y4 include: divalent organic groups represented by formula (H), divalent organic groups represented by formula (O), divalent organic groups represented by formula (O2), divalent organic groups with the group "-N(D)- (D represents a urethane protecting group)" in the molecule, and divalent organic groups with 6 to 30 carbon atoms other than D. Divalent organic groups obtained by removing two amino groups from the following diamines can also be listed.

[0078] Organic groups formed by removing two amino groups from the following diamines can be listed: groups represented by any of the formulas (Y-1) to (Y-167) as described in WO2018 / 117239: 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane; diamines having photo-oriented groups, such as the diamines represented by formulas (g-1) to (g-9) below; diamines having urea bonds, such as the diamines represented by formulas (u-1) to (u-3) below; diamines having amide bonds, such as the diamines represented by formulas (u-4) to (u-6) below; and heterocycles having nitrogen atoms selected from them. Diamines comprising at least one nitrogen-containing structure (hereinafter also referred to as nitrogen-containing structures) from the group consisting of secondary and tertiary amino groups; 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol; 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, and diamines having a carboxyl group, such as diamine compounds represented by formulas (3b-1) to (3b-4); 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 4,4'-diaminobenzophenone, 1-(4-aminophenyl)- 1,3,3-Trimethyl-1H-indane-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indane-6-amine; diamines with photopolymerizable groups at the ends, such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline; cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanostane 3,6-bis(4-aminophenyl) Diamines with a steroidal skeleton, such as benzoyloxy)cholestane; diamines shown in formulas (V-1) to (V-6) below; diamines with siloxane bonds, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; diamines with an oxazoline ring structure, such as formulas (Ox-1) to (Ox-2) below; 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 of 3,5-diaminobenzoic acid, 4,4'-diaminobenzophenone, and 3,3'-diaminobenzophenone.

[0079]

[0080]

[0081] (In (3b-1) above, A)1 The following symbols represent single bonds: -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -O-CH2-, -COO-, -OCO-, -CO-N(CH3)-, or -N(CH3)-CO-. m1 and m2 each independently represent integers from 0 to 4, and m1+m2 represents integers from 1 to 4. In equation (3b-2), m3 and m4 each independently represent integers from 1 to 5. In equation (3b-3), A... 2 m5 represents a straight-chain or branched alkyl group with 1 to 5 carbon atoms, where m5 represents an integer from 1 to 5. In formula (3b-4), A 3 and A 4 Each of these characters independently represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -O-CH2-, -COO-, -OCO-, -CO-N(CH3)-, or -N(CH3)-CO-, where m6 represents an integer from 1 to 4.

[0082]

[0083] (In the above formulas (V-1)~(V-6), X v1 ~X v4 and X p1 ~X p2 Each can be represented independently as -(CH2) a - (a is an integer from 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2-O-, -CH2-OCO-, -COO-, or -OCO-, X v5 This represents -O-, -CH2-O-, -CH2-OCO-, -COO-, or -OCO-. X a Represents single bonds, -O-, -NH-, -O-(CH2). m -O- (m represents an integer from 1 to 6), -C(CH3)2-, -CO-, -(CH2) m -, -SO2-, -O-C(CH3)2-, -CO-(CH2) m -(m represents an integer from 1 to 6), -NH-(CH2) m (m represents an integer from 1 to 6) -, -SO2-(CH2) m -(m represents an integer from 1 to 6), -CONH-(CH2) m-(m represents an integer from 1 to 6), -CONH-(CH2) m -NHCO- (m represents an integer from 1 to 6), -COO- (CH2) m -OCO- (m represents an integer from 1 to 6), -CONH-, -NH- (CH2) m -NH- (m represents an integer from 1 to 6), or -SO2-(CH2) m -SO2- (m represents an integer from 1 to 6), R v1 ~R v4 and R 1a ~R 1b Each of the two k groups independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. In formula (V-6), the two k groups may optionally be the same or different.

[0084]

[0085] Examples of nitrogen-containing heterocycles include: pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, isoquinoline, naphthidine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, hexamethyleneimine, etc. Among these, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, or acridine are preferred.

[0086] The secondary and tertiary amino groups optionally present in a diamine having a nitrogen-containing structure are represented, for example, by the following formula (n).

[0087]

[0088] In the above formula (n), R represents a hydrogen atom or a monovalent hydrocarbon group with 1 to 10 carbon atoms. "*1" represents a bond bonded to the hydrocarbon group.

[0089] Examples of monovalent hydrocarbon groups that can be represented by R in formula (n) above include: alkyl groups such as methyl, ethyl, and propyl; cycloalkyl groups such as cyclohexyl; and aryl groups such as phenyl and methylphenyl. R is preferably a hydrogen atom or a methyl group.

[0090] Specific examples of diamines having a nitrogen-containing structure include: 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, compounds represented by formulas (Dp-1) to (Dp-8), or compounds represented by formulas (z-1) to (z-28).

[0091]

[0092]

[0093]

[0094] (In the formula, Py represents a pyridine ring or a pyrimidine ring.)

[0095] From the viewpoint of efficiently obtaining the effects of the present invention, polymer (A) preferably contains the repeating unit (a1) and the imidized structure of the repeating unit (a1) in a manner that totals 10 to 100 mol% of all repeating units, and more preferably contains the repeating unit (a1) and the imidized structure of the repeating unit (a1) in a manner that totals 20 to 100 mol% of all repeating units. It should be noted that the total here also includes cases where any one of the repeating unit (a1) and the imidized structure of the repeating unit (a1) is 0 mol%. When total is mentioned again below, it also includes cases where one or more of the constituent elements are 0 mol%.

[0096] When polymer (A) contains repeating units other than repeating unit (a1) and imidized structure of repeating unit (a1), polymer (A) preferably contains repeating unit (a1) and imidized structure of repeating unit (a1) in a manner totaling 5 to 95 mol% of all repeating units, more preferably contains repeating unit (a1) and imidized structure of repeating unit (a1) in a manner totaling 5 to 90 mol% of all repeating units, and even more preferably contains repeating unit (a1) and imidized structure of repeating unit (a1) in a manner totaling 5 to 80 mol% of all repeating units.

[0097] From the viewpoint of efficiently obtaining the effects of the present invention, polymer (A) preferably contains the imidized structure of repeating unit (a2) and repeating unit (a2) in a manner that totals 5 to 95 mol% of all repeating units, more preferably contains the imidized structure of repeating unit (a2) and repeating unit (a2) in a manner that totals 10 to 95 mol% of all repeating units, and even more preferably contains the imidized structure of repeating unit (a2) and repeating unit (a2) in a manner that totals 20 to 95 mol% of all repeating units.

[0098] From the viewpoint of efficiently obtaining the effects of the present invention, polymer (A) preferably contains repeating units (a1) and (a2) and their imidized structures in a manner that totals at least 10 mol% of all repeating units, more preferably in a manner that totals at least 20 mol% of all repeating units. When polymer (A) contains repeating units other than repeating units (a1) and (a2) and their imidized structures, polymer (A) preferably contains repeating units (a1) and (a2) and their imidized structures in a manner that totals at least 95 mol% of all repeating units, more preferably in a manner that totals at least 90 mol% of all repeating units.

[0099] In cases where polymer (A) comprises at least any one of the imidized structures of repeating unit (a2') and repeating unit (a2'), from the viewpoint of efficiently obtaining the effects of the present invention, polymer (A) preferably comprises the imidized structure of repeating unit (a2') and repeating unit (a2') in a manner totaling 1 to 50 mol% of all repeating units, more preferably in a manner totaling 1 to 40 mol% of all repeating units, and even more preferably in a manner totaling 1 to 30 mol% of all repeating units.

[0100] From the viewpoint of efficiently obtaining the effects of the present invention, it is preferred that the polymer (A) comprises: at least any one of repeating units (a1) and their imidized structures, at least any one of repeating units (a2) and their imidized structures, and at least any one of repeating units (a2') and their imidized structures, wherein the total of repeating units (a1), repeating units (a2), and repeating units (a2') and their imidized structures is 30 mol% or more of all repeating units, more preferably 40 mol% or more of all repeating units. When polymer (A) contains repeating units other than repeating units (a1), repeating units (a2) and repeating units (a2') and their imidized structures, polymer (A) preferably contains repeating units (a1), repeating units (a2) and repeating units (a2') and their imidized structures in a manner that totals less than 95 mol% of all repeating units, and more preferably contains repeating units (a1), repeating units (a2) and repeating units (a2') and their imidized structures in a manner that totals less than 90 mol% of all repeating units.

[0101] From the viewpoint of properly obtaining the effects of the present invention, relative to 1 mole of all structural units derived from tetracarboxylic acid derivatives in polymer (A), polymer (A) more preferably contains 50 mol% or more of structural units derived from tetracarboxylic acid derivatives having the tetravalent organic group shown in formula (g) above, more preferably contains 70 mol% or more of structural units derived from tetracarboxylic acid derivatives having the tetravalent organic group shown in formula (g) above, and particularly preferably contains 90 mol% or more of structural units derived from tetracarboxylic acid derivatives having the tetravalent organic group shown in formula (g) above.

[0102] In cases where the polymer (A) comprises at least any one of the repeating unit (a3) ​​and the imidized structure of the repeating unit (a3), from the viewpoint of efficiently obtaining the effects of the present invention, the polymer (A) preferably comprises the repeating unit (a3) ​​and the imidized structure of the repeating unit (a3) ​​in a manner totaling 1 to 40 mol% of all repeating units, more preferably in a manner totaling 1 to 30 mol% of all repeating units, and even more preferably in a manner totaling 1 to 25 mol% of all repeating units.

[0103] The polymer (A) may also contain repeating units (a2') and repeating units (a3) ​​and their imidized structures.

[0104] <Polymer (B)>

[0105] In addition to the polymer (A) described above, the liquid crystal alignment agent of the present invention may also contain a polymer (B) that does not have the repeating unit (a1) described above in its molecule. From the viewpoint of efficiently obtaining the effects of the present invention, polymer (B) can be listed as at least one polymer selected from the group consisting of a polyimide precursor having the repeating unit shown in the following formula (5) and a polyimide as an imide derivative of the polyimide precursor.

[0106]

[0107] (In the formula, X5 is a tetravalent organic group, and Y5 is a divalent organic group. Z independently represents a hydrogen atom, an alkyl group with 1 to 10 carbon atoms optionally having a substituent, an alkenyl group with 2 to 10 carbon atoms optionally having a substituent, an alkynyl group with 2 to 10 carbon atoms optionally having a substituent, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group. R independently represents a hydrogen atom or an alkyl group with 1 to 4 carbon atoms.)

[0108] As examples of the tetravalent organic groups in X5 above, the following can be listed: tetravalent organic groups derived from aliphatic tetracarboxylic dianhydrides, tetravalent organic groups derived from alicyclic tetracarboxylic dianhydrides, or tetravalent organic groups derived from aromatic tetracarboxylic dianhydrides. Specific examples include the aforementioned X... 2’ And the tetravalent organic group exemplified in X3. From the viewpoint of efficiently obtaining the effects of the present invention, X5 is preferably the tetravalent organic group shown in formula (g) above, the tetravalent organic group shown in any of the formulas (X-1) to (X-25) above, the tetravalent organic group shown in formulas (Xa-1) to (Xa-2) above, or the tetravalent organic group shown in formulas (Xr-1) to (Xr-7) above (also collectively referred to as specific tetravalent organic groups).

[0109] From the viewpoint of efficiently obtaining the effects of the present invention, polymer (B) preferably contains repeating units in which X5 is the aforementioned specific tetravalent organic group in a manner that comprises 5 mol% or more of all repeating units contained in polymer (B), and more preferably contains repeating units in which X5 is the aforementioned specific tetravalent organic group in a manner that comprises 10 mol% or more of all repeating units contained in polymer (B).

[0110] As divalent organic groups in Y5 above, examples of divalent organic groups shown in Y4 above can be cited. From the viewpoint of minimizing residual DC residues, polymer (B) is preferably a polymer containing repeating units in which Y5 is a divalent organic group obtained by removing two amino groups from the above-mentioned diamines having urea bonds, diamines having amide bonds, diamines having nitrogen-containing structures, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, and diamines having carboxyl groups (these are also collectively referred to as specific divalent organic groups).

[0111] From the viewpoint of having few residual images originating from residual DC, polymer (B) may contain repeating units in which Y5 is the aforementioned specific divalent organic group in a manner that comprises more than 1 mol% of all repeating units contained in polymer (B), or may contain repeating units in which Y5 is the aforementioned specific divalent organic group in a manner that comprises more than 5 mol% of all repeating units contained in polymer (B).

[0112] From the perspective of minimizing residual images originating from residual DC, the content ratio of polymer (A) to polymer (B), expressed as the mass ratio of [polymer (A)] / [polymer (B)], can be 10 / 90 to 90 / 10, 20 / 80 to 90 / 10, or 20 / 80 to 80 / 20.

[0113] <Methods for manufacturing polyamic acid, polyamic acid esters and polyimide>

[0114] The polyamic acid esters and polyamic acids used as polyimide precursors in this invention, as well as the polyimides as their imide derivatives, can be synthesized, for example, by known methods as described in WO2013 / 157586.

[0115] More specifically, this is carried out by reacting the diamine component with the tetracarboxylic acid derivative component in a solvent (condensation). If a portion of polymer (A) or (B) contains an ammonium acid structure, for example, by reacting the tetracarboxylic acid dianhydride component with the diamine component, a polymer (polyamic acid) having an ammonium acid structure is obtained. The solvent is not particularly limited as long as it dissolves the resulting polymer.

[0116] Specific examples of the solvents mentioned above include: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolinone. Furthermore, where the polymer has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or solvents represented by formulas [D-1] to [D-3] below can be used.

[0117]

[0118] (In formula [D-1], D) 1 In formula [D-2], D represents an alkyl group with 1 to 3 carbon atoms. 2 In formula [D-3], D represents an alkyl group having 1 to 3 carbon atoms. 3 (This refers to alkyl groups having 1 to 4 carbon atoms.)

[0119] These solvents can be used alone or in combination. Moreover, even solvents that do not dissolve polymers can be mixed with the aforementioned solvents as long as the resulting polymer does not precipitate.

[0120] When the diamine component reacts with the tetracarboxylic acid derivative component in a solvent, the reaction can be carried out at any concentration, preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration initially, followed by the addition of solvent.

[0121] In the reaction, the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic acid derivative component is preferably 0.8 to 1.2. Similar to conventional polycondensation reactions, the closer this molar ratio is to 1.0, the larger the molecular weight of the resulting polymers (A) and (B).

[0122] Polyamates can be obtained, for example, by known methods such as: [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.

[0123] Methods for obtaining polyimide include: thermal imidization by heating a solution of the polymer obtained by the above reaction while maintaining it in this state; or catalytic imidization by adding a catalyst to the polymer solution. In the case of thermal imidization in solution, the temperature is 100–400°C, preferably 120–250°C, and preferably the process is carried out while removing water generated by the imidization reaction from the system.

[0124] The above-mentioned catalyst imidization can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polymer obtained in the reaction, preferably at -20 to 250°C, more preferably at 0 to 180°C. The amount of basic catalyst is preferably 0.5 to 30 molar times that of the amic acid group, more preferably 2 to 20 molar times, and the amount of acid anhydride is preferably 1 to 50 molar times that of the amic acid group, more preferably 3 to 30 molar times. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, etc., among which pyridine has a suitable basicity to promote the reaction and is therefore preferred. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, etc., among which acetic anhydride facilitates purification after the reaction and is therefore preferred. The imidization rate (the ratio of the repeating unit of the closed ring to all repeating units possessed by the polyimide precursor, also known as the ring closure rate) based on the catalyst imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[0125] In recovering the generated imide from the above-mentioned imidization reaction solution, the reaction solution can be precipitated simply 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 in the solvent can be recovered by filtration and then dried at room temperature or under normal or reduced pressure, or by heating.

[0126] With regard to the polyimide in the polymer (A) of the present invention, some or all of the repeating units of the aforementioned polyimide precursor are closed-ringed. In the aforementioned polyimide, the imidization rate is preferably 20-95%, more preferably 30-95%, and even more preferably 50-95%.

[0127] <Polymer solution viscosity / molecular weight>

[0128] Regarding the polyamic acid, polyamic acid ester, and polyimide used in this invention, from an operational point of view, when preparing a solution with a concentration of 10-15% by mass, a solution viscosity of 10-1000 mPa·s is preferred, for example, but not particularly limited. It should be noted that the solution viscosity (mPa·s) of the aforementioned polymers is a value measured at 25°C using an E-type rotational viscometer for a polymer solution with a concentration of 10-15% by mass prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0129] The weight-average molecular weight (Mw) of the polyamic acid, polyamic acid ester, and polyimide, as determined by gel permeation chromatography (GPC), converted from polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. Furthermore, the molecular weight distribution (Mw / Mn) shown by the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC is preferably 15 or less, more preferably 10 or less. Within this molecular weight range, good orientation and stability of the liquid crystal display element can be ensured.

[0130] <End-capping agent>

[0131] When synthesizing polymers (A) and (B) of this invention, they can also be synthesized using a suitable capping agent together with the tetracarboxylic acid derivative component and the diamine component as described above. The capped polymers have the effect of increasing the film hardness of the liquid crystal alignment film obtained by coating and improving the adhesion properties between the sealant and the liquid crystal alignment film.

[0132] Examples of the ends of polymers (A) and (B) in this invention include amino, carboxyl, anhydride, or derivatives thereof. The amino, carboxyl, anhydride, or terminal groups derived from these groups can be obtained by conventional condensation reactions; or by end-capping the ends using end-capping agents, for example, the derivatives of which can also be obtained using end-capping agents.

[0133] 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.; di-tert-butyl dicarbonate, diallyl dicarbonate, etc. Dicarbonate compounds; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinyl chloride; monoamine compounds such as aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate, and naphthyl isocyanate.

[0134] 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.

[0135] <Liquid Crystal Alignment Agent>

[0136] The liquid crystal alignment agent of the present invention contains polymer (A) and, if necessary, polymer (B). In addition to polymer (A) and polymer (B), the liquid crystal alignment agent of the present invention may also contain other polymers. Examples of other polymers include: polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivatives, poly(meth)acrylates, etc.

[0137] Liquid crystal alignment agents are used to produce liquid crystal alignment films, and from the viewpoint of forming a uniform thin film, they are preferably in the form of a coating liquid. In the liquid crystal alignment agent of the present invention, a coating liquid containing the aforementioned polymer component and organic solvent is preferred. In this case, the concentration of the polymer in the liquid crystal alignment agent can be appropriately varied according to the desired thickness of the coating film. From the viewpoint of forming a uniform and defect-free coating film, it is preferably 1% by mass or more, and from the viewpoint of the storage stability of the solution, it is preferably 10% by mass or less. A particularly preferred polymer concentration is 2 to 8% by mass.

[0138] The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as it uniformly dissolves the polymer components. Specific examples include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactic acid, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-... Dimethylpropionamide, N-n-propyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-n-butyl-2-pyrrolidone, N-tert-butyl-2-pyrrolidone, N-n-pentyl-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone (also collectively referred to as "good solvents"), etc. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, or γ-butyrolactone are preferred. The content of the good solvent is preferably 20-99% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 20-90% by mass, and particularly preferably 30-80% by mass.

[0139] 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). 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 can be appropriately selected according to the coating apparatus, coating conditions, coating environment, etc. of the liquid crystal alignment agent. Specific examples of the poor solvents used are described below, but are not limited thereto.

[0140] Examples include: diisopropyl ether, diisobutyl ether, diisobutylmethanol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxyethyl acetate, 1-methylpentyl acetate, 2-ethylethyl butyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)- 2-Propanol, 2-(2-Butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0141] 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.

[0142] Preferred combinations of solvents, representing good and poor solvents, include: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-dimethyllacticamide and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone and ethylene glycol... Monobutyl ether acetate; N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether; N,N-dimethyl lactamide and ethylene glycol monobutyl ether; N,N-dimethyl lactamide and propylene glycol diacetate; N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether; N,N-dimethyl lactamide and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy 4-Methyl-2-pentanone and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether Ethers and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutylmethanol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and propylene glycol diacetate; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and diisobutyl ketone; N-ethyl-2-pyrrolidone, γ-butyrolactone and diisobutyl ketone; N-ethyl-2-pyrrolidone, N,N-dimethyllactic acid and diisobutyl ketone, etc.

[0143] The liquid crystal alignment agent of the present invention may also contain additional components (hereinafter also referred to as additive components) other than polymer components and organic solvents. Examples of such additive components include: adhesion promoters for improving the adhesion between the liquid crystal alignment film and the substrate, and the adhesion between the liquid crystal alignment film and the sealant; compounds for improving the strength of the liquid crystal alignment film (hereinafter also referred to as crosslinking compounds); and dielectrics and conductive materials for adjusting the dielectric constant and resistance of the liquid crystal alignment film.

[0144] From the viewpoint of exhibiting good resistance to AC remnants and significantly improving film strength, the aforementioned crosslinking compound may be at least one compound selected from the group consisting of: compounds having at least one group selected from the group consisting of ethylene oxide, oxetane, protected isocyanate group, protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Michaelis acid structure, a cyclic carbonate group, and a group represented by formula (d) below; and compounds represented by formula (e) below.

[0145]

[0146] (In formula (d), R2 and R3 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH". In formula (e), A represents an (m+n) valence organic group having an aromatic ring, R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, m represents an integer from 1 to 6, and n represents an integer from 0 to 4. Any hydrogen atom on the above aromatic ring may optionally be replaced by a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkenyl group having 2 to 10 carbon atoms, or a fluoroalkoxy group having 1 to 10 carbon atoms.)

[0147] Specific examples of compounds containing ethylene oxide include compounds described in paragraph 0037 of Japanese Patent Application Publication No. 10-338880 and compounds with a triazine ring in their skeleton as described in WO2017 / 170483, as well as compounds containing two or more ethylene oxide groups. These may include compounds containing nitrogen atoms, such as N,N,N',N'-tetraglycidyl-m-phenylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, and compounds shown in formulas (r-1) to (r-3) below.

[0148]

[0149] Specific examples of compounds having oxetane groups include compounds having two or more oxetane groups as described in paragraphs 0170 to 0175 of WO2011 / 132751.

[0150] Specific examples of compounds having protected isocyanate groups include compounds having two or more protected isocyanate groups as described in paragraphs 0046 to 0047 of Japanese Patent Application Publication No. 2014-224978, and compounds having three or more protected isocyanate groups as described in paragraphs 0119 to 0120 of WO2015 / 141598, which can be compounds represented by the formulas (bi-1) to (bi-3) below.

[0151]

[0152] Specific examples of compounds having protected isothiocyanate groups include compounds having two or more protected isothiocyanate groups as described in Japanese Patent Application Publication No. 2016-200798.

[0153] Specific examples of compounds having groups containing an oxazoline ring structure include compounds containing two or more oxazoline ring structures as described in paragraph 0115 of Japanese Patent Application Publication No. 2007-286597.

[0154] As a specific example of a compound having a group containing a Michaelis acid structure, compounds having two or more Michaelis acid structures as described in WO2012 / 091088 can be cited.

[0155] Specific examples of compounds having cyclic carbonate groups include the compounds described in WO2011 / 155577.

[0156] Examples of alkyl groups with 1 to 3 carbon atoms in R2 and R3, which are groups shown in formula (d) above, include: methyl, ethyl, propyl, and isopropyl.

[0157] Specific examples of compounds having the groups shown in formula (d) above include: compounds having two or more groups shown in formula (d) above as described in paragraph 0058 of Japanese Patent Application Publication No. WO2015 / 072554 and Japanese Patent Application Publication No. 2016-118753, and compounds described in Japanese Patent Application Publication No. 2016-200798, which can be compounds shown in formulas (hd-1) to (hd-8) below.

[0158]

[0159] Examples of (m+n) valence organic groups having aromatic rings in A of formula (e) above include: (m+n) valence aromatic hydrocarbon groups with 6 to 30 carbon atoms; (m+n) valence organic groups formed by direct or via linking groups of aromatic hydrocarbon groups with 6 to 30 carbon atoms; and (m+n) valence groups having aromatic heterocycles. Examples of the aforementioned aromatic hydrocarbon groups include benzene and naphthalene. Examples of aromatic heterocycles include: pyrrole rings, imidazole rings, pyrazole rings, pyridine rings, pyrimidine rings, quinoline rings, isoquinoline rings, carbazole rings, pyridazine rings, pyrazine rings, benzimidazole rings, indole rings, quinoxaline rings, and acridine rings. Examples of the aforementioned linking groups include: alkylene groups with 1 to 10 carbon atoms, -NR- (where R is a hydrogen atom or an alkyl group with 1 to 6 carbon atoms), or groups formed by removing one hydrogen atom from the aforementioned alkylene groups, and divalent or trivalent cyclohexane rings. It should be noted that any hydrogen atom of the aforementioned alkylene group may optionally be replaced by an alkyl group having 1 to 6 carbon atoms, a fluorine atom, or an organic group such as trifluoromethyl. Specific examples of alkyl groups having 1 to 5 carbon atoms in R of the above formula (e) can be listed, including those exemplified in R1 to R4 of the above formula (1).

[0160] If specific examples of the above formula (e) are given, the compounds described in WO2010 / 074269 and the compounds shown in the following formulas (e-1) to (e-10) can be listed.

[0161]

[0162] The above-described compound is an example of a cross-linking compound, but is not limited thereto. For example, other components not described above may be listed in paragraphs 0105 on page 53 to 0116 on page 55 of WO2015 / 060357. Furthermore, two or more cross-linking compounds may be combined.

[0163] The content of the crosslinking compound in the liquid crystal alignment agent of the present invention is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent. From the viewpoint of promoting the progress of the crosslinking reaction and exhibiting good resistance to AC image retention, it is more preferably 1 to 15 parts by mass.

[0164] Examples of such sealing agents include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, etc. oxysilanes, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-(3-triethoxysilylpropyl)triethylenetetramine, N-(3-trimethoxysilylpropyl)triethylenetetramine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonylacetate, 9-triethoxysilyl-3,6-diazanonylacetate, N-benzyl-3- Aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane The silane coupling agents include styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris(3-trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane. When using silane coupling agents, from the viewpoint of exhibiting good resistance to AC image retention, the polymer content 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.

[0165] <Liquid crystal alignment film / liquid crystal display element>

[0166] The liquid crystal alignment film of the present invention is obtained from the above-described liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used for horizontally aligned or vertically aligned (VA type) liquid crystal alignment films, wherein the liquid crystal alignment film of the present invention is suitable for horizontally aligned liquid crystal display elements such as IPS or FFS types. Furthermore, it is more preferably used for liquid crystal alignment films for photo-alignment processing. The liquid crystal display element of the present invention includes the above-described liquid crystal alignment film. The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following steps (1) to (3) and (5) or steps (1) to (2) and (5). It is more preferably manufactured by a method including steps (1) to (5).

[0167] <Process (1): The process of coating the liquid crystal alignment agent onto the substrate>

[0168] 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 roller coating, spin coating, printing, or inkjet coating. Here, the substrate is not particularly limited as long as it has high transparency; it can also be used in conjunction with glass substrates, silicon nitride substrates, or plastic substrates such as acrylic substrates or polycarbonate substrates. Furthermore, in reflective liquid crystal display elements, if the substrate is only on one side, an opaque material such as a silicon wafer can be used, and the electrodes can be made of light-reflecting materials such as aluminum. In addition, when manufacturing IPS or FFS type liquid crystal elements, a substrate having electrodes composed of a patterned comb-shaped transparent conductive film or metal film and an opposing substrate without electrodes are used.

[0169] 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.

[0170] <Process (2): The process of firing the coated liquid crystal alignment agent>

[0171] Step (2) is a process of firing the liquid crystal alignment agent coated on the substrate to form a film. After the liquid crystal alignment agent is coated on the substrate, the solvent can be evaporated by 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 process after coating the liquid crystal alignment agent of the present invention can be performed at any temperature and time, and can be performed multiple times. For example, the firing temperature of the liquid crystal alignment agent can be performed at 40 to 180°C. From the viewpoint of shortening the process, it can be performed at 40 to 150°C. The firing time is not particularly limited, 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, the firing process can also be performed after the above firing process, for example, at a temperature range of 150 to 300°C or 150 to 250°C. The firing time is not particularly limited, and examples include 5 to 40 minutes or 5 to 30 minutes.

[0172] If the film after firing is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, 5 to 300 nm is preferred, and 10 to 200 nm is more preferred.

[0173] <Step (3): The step of oriented treatment of the film obtained in step (2)>

[0174] Step (3) is a step of aligning the film obtained in step (2) depending on the situation. That is, in horizontally aligned liquid crystal display elements such as IPS or FFS, the coating is subjected to an alignment capability imparting treatment. On the other hand, in vertically aligned liquid crystal display elements such as VA or PSA, 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, brushing treatment and photo-alignment treatment can be listed, and photo-alignment treatment is more preferred. As a photo-alignment treatment method, the following method can be listed: irradiating the surface of the above-mentioned film with radiation biased in a certain direction, and, depending on the situation, preferably performing a heat treatment at a temperature of 150 to 250°C to impart liquid crystal alignment (also known as liquid crystal alignment capability). As radiation, ultraviolet light or visible light with a wavelength of 100 to 800 nm can be used. Among them, ultraviolet light with a wavelength of 100 to 400 nm is preferred, and ultraviolet light with a wavelength of 200 to 400 nm is more preferred.

[0175] The preferred radiation dose is 1–10,000 mJ / cm². 2 More preferably, it is 100–5000 mJ / cm². 2 More preferably, it is 100–1500 mJ / cm 2 The preferred value is 100–1000 mJ / cm³.2 More preferably, it is 100–400 mJ / cm 2 When using conventional liquid crystal alignment agents, the light irradiation dose during the alignment process is 100–5000 mJ / cm². 2 However, in the liquid crystal alignment agent of the present invention, even if the amount of light irradiation during the alignment process is reduced, a liquid crystal alignment film that suppresses the deviation (non-uniformity) of liquid crystal alignment within the liquid crystal alignment film surface can be obtained.

[0176] Furthermore, to improve liquid crystal alignment when irradiated with radiation, the substrate having the above-mentioned film can be irradiated while being heated at 50–250°C. The liquid crystal alignment film produced in this way allows the liquid crystal molecules to be stably aligned in a specific direction.

[0177] Furthermore, in the above methods, water or solvents can be used to contact the liquid crystal alignment film irradiated with polarized radiation; or the liquid crystal alignment film irradiated with radiation can be heated.

[0178] The solvent used in the above-mentioned contact treatment is not particularly limited as long as it dissolves the decomposition products generated by the film-like material through radiation irradiation. 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, considering versatility and solvent safety, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred. 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.

[0179] <Step (4): A step of heat-treating the film that has undergone orientation treatment in step (3) at 50-300°C>

[0180] The coating that has been irradiated with the above-mentioned radiation can also be heat-treated.

[0181] The preferred temperature for heat treatment of the coating irradiated with the aforementioned radiation is 50–300°C, more preferably 120–250°C. The preferred heat treatment time is 1–30 minutes.

[0182] <Process (5): Process of manufacturing LCD cell>

[0183] Prepare two substrates with liquid crystal alignment films formed thereon as described above, and place liquid crystal between the two substrates arranged opposite each other. Specifically, the following two methods can be listed. In the first method, firstly, the two substrates are arranged opposite each other with a gap (cell gap) between them, with each liquid crystal alignment film facing each other. Next, the peripheral portions of the two substrates are bonded together using a sealant, and a liquid crystal filling composition is injected into the cell gap defined by the substrate surfaces and the sealant. After contacting the film surface, the injection hole is sealed.

[0184] In addition, a second method is known as the ODF (One Drop Fill) method. For example, a UV-curable sealant is applied to a predetermined area on one of the two substrates forming the liquid crystal alignment film, and then a liquid crystal composition is dropped onto several predetermined points on the surface of the alignment film. The other substrate is then bonded with the alignment films facing each other, and the liquid crystal composition is spread across the entire surface of the substrate, contacting the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. Regardless of the method used, it is ideal to further heat the liquid crystal composition to a temperature at which it becomes an isotropic phase, and then slowly cool it to room temperature, thereby removing the flow alignment during liquid crystal filling.

[0185] It should be noted that when the coating is brushed, the two substrates are arranged at a predetermined angle to each other with the brushing direction of each coating, for example, in an orthogonal or antiparallel manner.

[0186] As a sealant, epoxy resin containing a curing agent and alumina spheres as spacers can be used, for example. Nematic liquid crystals and smectic liquid crystals can be cited as examples, with nematic liquid crystals being preferred.

[0187] 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.

[0188] The IPS substrate, which is a comb-electrode substrate used in IPS (In-Plane Switching) mode, includes: a substrate; a plurality of linear electrodes formed on the substrate and configured in a comb-like shape; and a liquid crystal alignment film formed on the substrate in such a way as to cover the linear electrodes.

[0189] It should be noted that the FFS substrate, which is used as a comb electrode substrate in the FFS (Frindge Field Switching) mode, has: a substrate; a surface electrode formed on the substrate; an insulating film formed on the surface electrode; a plurality of linear electrodes formed on the insulating film and configured in a comb shape; and a liquid crystal alignment film formed on the insulating film in a manner that covers the linear electrodes.

[0190] Figure 1 This is a schematic cross-sectional view showing an example of a lateral electric field liquid crystal display element of the present invention, which is an example of an IPS mode liquid crystal display element.

[0191] exist Figure 1 In the lateral electric field liquid crystal display element 1 illustrated in the example, liquid crystal 3 is held between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2c and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 includes: a substrate 2a; a plurality of linear electrodes 2b formed on the substrate 2a and arranged in a comb-like shape; and a liquid crystal alignment film 2c formed on the substrate 2a to cover the linear electrodes 2b. The opposing substrate 4 includes: a substrate 4b and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2c is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4c is also, similarly, the liquid crystal alignment film of the present invention.

[0192] In this transverse electric field liquid crystal display element 1, when a voltage is applied to the linear electrode 2b, an electric field is generated between the linear electrodes 2b as shown by the electric field line L.

[0193] Figure 2 This is a schematic cross-sectional view showing another example of the transverse electric field liquid crystal display element of the present invention, which is an example of an FFS mode liquid crystal display element.

[0194] exist Figure 2 In the lateral electric field liquid crystal display element 1 illustrated in the example, liquid crystal 3 is held between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2h and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 includes: a substrate 2d; a surface electrode 2e formed on the substrate 2d; an insulating film 2f formed on the surface electrode 2e; a plurality of linear electrodes 2g arranged in a comb-like pattern formed on the insulating film 2f; and a liquid crystal alignment film 2h formed on the insulating film 2f to cover the linear electrodes 2g. The opposing substrate 4 includes: a substrate 4b and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2h is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4a is also, similarly, the liquid crystal alignment film of the present invention.

[0195] 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.

[0196] Example

[0197] The following examples illustrate the invention in further detail, but the invention is not limited thereto. The abbreviations of the compounds and the methods for determining their properties are described below.

[0198] (solvent)

[0199] NMP: N-methyl-2-pyrrolidone.

[0200] BCS: Butyl cellosolve.

[0201] (Diamine)

[0202] DA-1: p-phenylenediamine.

[0203] DA-2: 1,2-bis(4-aminophenoxy)ethane.

[0204] DA-3: Refer to the following formula (DA-3).

[0205] DA-4: Refer to the following formula (DA-4).

[0206] DA-5: Refer to the following formula (DA-5).

[0207] DA-6: Refer to the following formula (DA-6).

[0208] DA-7: 1,3-bis(4-aminophenylethyl)urea.

[0209] DA-8: 4-(2-methylaminoethyl)aniline.

[0210] (Tetracarboxylic acid dianhydride)

[0211] TA-1: 1,3-Dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride. TA-2: 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride.

[0212]

[0213] “Boc” represents tert-butoxycarbonyl. “Me” represents methyl.

[0214] [Viscosity]

[0215] The viscosity of the solution was measured using a TVE-22H type E viscometer (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL, a conical rotor TE-1 (1°34', R24), at a temperature of 25°C.

[0216] [Examples of polymer synthesis]

[0217] <Synthesis example 1>

[0218] 0.173 g (1.60 mmol) of DA-1, 0.586 g (2.40 mmol) of DA-2, 0.836 g (2.40 mmol) of DA-4, and 0.638 g (1.60 mmol) of DA-3 were measured into a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. 28.9 g of NMP was added, and the solution was stirred while adding nitrogen to dissolve the diamine. While stirring the solution, 1.704 g (7.60 mmol) of TA-1 was added, and the mixture was stirred at 50 °C for 20 hours to obtain a polyamic acid solution (PAA-1). The viscosity of this polyamic acid solution was 840 mPa·s.

[0219] <Synthesis example 2>

[0220] 0.130 g (1.20 mmol) of DA-1, 0.440 g (1.80 mmol) of DA-2, 0.678 g (1.80 mmol) of DA-5, and 0.478 g (1.20 mmol) of DA-3 were measured into a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. 21.9 g of NMP was added, and the solution was stirred while adding nitrogen to dissolve the diamine. While stirring the solution, 1.264 g (5.64 mmol) of TA-1 was added, and the mixture was stirred at 50 °C for 20 hours to obtain a polyamic acid solution (PAA-2). The viscosity of this polyamic acid solution was 394 mPa·s.

[0221] <Synthesis Example 3>

[0222] 0.076 g (0.70 mmol) of DA-1, 0.257 g (1.05 mmol) of DA-2, 0.429 g (1.05 mmol) of DA-6, and 0.279 g (0.70 mmol) of DA-3 were measured into a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. 13.3 g of NMP was added, and the mixture was stirred while adding nitrogen to dissolve the diamine solution. While stirring the solution, 0.738 g (3.29 mmol) of TA-1 was added, and the mixture was stirred at 50 °C for 20 hours to obtain a polyamic acid solution (PAA-3). The viscosity of this polyamic acid solution was 374 mPa·s.

[0223] <Synthesis Example 4>

[0224] 9.01 g (60.0 mmol) of DA-8 and 26.8 g (89.8 mmol) of DA-7 were added to a 500 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. 290 g of NMP was added, and the mixture was stirred while adding nitrogen to dissolve the diamine solution. While stirring the solution under water cooling, 27.9 g (142 mmol) of TA-2 and 71.4 g of NMP were added. The mixture was stirred at 23 °C for 2 hours to obtain a polyamic acid solution (PAA-4).

[0225] The viscosity of the polyamic acid solution is 750 mPa·s.

[0226] <Synthesis example 5>

[0227] 0.108 g (1.00 mmol) of DA-1, 0.366 g (1.50 mmol) of DA-2, 0.565 g (1.50 mmol) of DA-5, and 0.399 g (1.00 mmol) of DA-3 were measured into a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. 17.2 g of NMP was added, and the solution was stirred while adding nitrogen to dissolve the diamine. While stirring the solution, 0.912 g (4.65 mmol) of TA-2 was added, and the mixture was stirred at 40 °C for 24 hours to obtain a polyamic acid solution (PAA-5). The viscosity of this polyamic acid solution was 373 mPa·s.

[0228] [Preparation of Liquid Crystal Alignment Agent]

[0229] <Example 1>

[0230] 5.00 g of the 12% by mass polyamic acid solution (PAA-2) obtained in Synthesis Example 2 was transferred to a 20 mL Erlenmeyer flask, and 3.40 g of NMP and 3.60 g of BCS were added. The mixture was stirred at 25 °C for 2 hours to obtain the liquid crystal alignment agent (A1). It was confirmed that no abnormalities such as turbidity or precipitation were found in the liquid crystal alignment agent, and it was a homogeneous solution.

[0231] <Example 2>

[0232] 5.00 g of the 12% by mass polyamic acid solution (PAA-3) obtained in Synthesis Example 3 was transferred to a 20 mL Erlenmeyer flask, and 3.40 g of NMP and 3.60 g of BCS were added. The mixture was stirred at 25 °C for 2 hours to obtain the liquid crystal alignment agent (A2). It was confirmed that no abnormalities such as turbidity or precipitation were found in the liquid crystal alignment agent, and it was a homogeneous solution.

[0233] <Example 3>

[0234] 0.83 g of the 12% by mass polyamic acid solution (PAA-2) obtained in Synthesis Example 2 and 2.67 g of the 15% by mass polyamic acid solution (PAA-4) obtained in Synthesis Example 4 were transferred to a 20 mL Erlenmeyer flask. 4.50 g of NMP and 2.00 g of BCS were added, and the mixture was stirred at 25°C for 2 hours to obtain the liquid crystal alignment agent (A3). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0235] <Example 4>

[0236] 0.83 g of the 12% by mass polyamic acid solution (PAA-3) obtained in Synthesis Example 3 and 2.67 g of the 15% by mass polyamic acid solution (PAA-4) obtained in Synthesis Example 4 were transferred to a 20 mL Erlenmeyer flask. 4.50 g of NMP and 2.00 g of BCS were added, and the mixture was stirred at 25°C for 2 hours to obtain the liquid crystal alignment agent (A4). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0237] <Comparative Example 1>

[0238] 5.00 g of the 12% by mass polyamic acid solution (PAA-1) obtained in Synthesis Example 1 was transferred to a 20 mL Erlenmeyer flask, and 3.40 g of NMP and 3.60 g of BCS were added. The mixture was stirred at 25 °C for 2 hours to obtain the liquid crystal alignment agent (B1). It was confirmed that no abnormalities such as turbidity or precipitation were found in the liquid crystal alignment agent, and it was a homogeneous solution.

[0239] <Comparative Example 2>

[0240] 0.83 g of the 12% by mass polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 2.67 g of the 15% by mass polyamic acid solution (PAA-4) obtained in Synthesis Example 4 were transferred to a 20 mL Erlenmeyer flask. 4.50 g of NMP and 2.00 g of BCS were added, and the mixture was stirred at 25°C for 2 hours to obtain the liquid crystal alignment agent (B2). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0241] <Comparative Example 3>

[0242] 5.00 g of the 12% by mass polyamic acid solution (PAA-5) obtained in Synthesis Example 5 was transferred to a 20 mL Erlenmeyer flask, and 3.40 g of NMP and 3.60 g of BCS were added. The mixture was stirred at 25 °C for 2 hours to obtain the liquid crystal alignment agent (B3). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0243] <Comparative Example 4>

[0244] 0.83 g of the 12% by mass polyamic acid solution (PAA-5) obtained in Synthesis Example 5 and 2.67 g of the 15% by mass polyamic acid solution (PAA-4) obtained in Synthesis Example 4 were placed in a 20 mL Erlenmeyer flask. 4.50 g of NMP and 2.00 g of BCS were added, and the mixture was stirred at 25°C for 2 hours to obtain the liquid crystal alignment agent (B4). It was confirmed that the liquid crystal alignment agent was a homogeneous solution without any abnormalities such as turbidity or precipitation.

[0245] [Table 1]

[0246]

[0247] Using the liquid crystal alignment agent obtained as described above, an FFS-driven liquid crystal cell was fabricated in the order shown below, and its characteristics were evaluated.

[0248] [Making of LCD Cells]

[0249] A liquid crystal cell with a fringe field switching (FFS) mode liquid crystal display element was manufactured.

[0250] First, a substrate with electrodes was prepared. The substrate was a glass substrate with a size of 30mm x 335mm and a thickness of 0.7mm. On the substrate, an ITO electrode with a dense pattern, constituting the counter electrode, was formed as a first layer. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by CVD was formed as a second layer. The thickness of the second SiN film was 500nm, which served as an interlayer insulating film. On the second SiN film, a comb-shaped pixel electrode formed by patterning the ITO film was disposed as a third layer, forming two types of pixels: a first pixel and a second pixel. Each pixel was approximately 6mm long and 5mm wide. At this point, the counter electrode of the first layer and the pixel electrode of the third layer were electrically insulated by the SiN film of the second layer.

[0251] The pixel electrodes of the third layer have a comb-like shape formed by arranging multiple electrode elements with a central portion bent at an interior angle of 160° in a "<" shape. The width of each electrode element in the short dimension is 3 μm, and the spacing between the electrode elements is 6 μm. Since the pixel electrodes forming each pixel are composed of multiple electrode elements with a central portion bent in a "<" shape, the shape of each pixel is not rectangular, but rather has a shape resembling a bold "<" shape, similar to the electrode elements, with a central portion bent. Furthermore, each pixel is divided into upper and lower regions by its central bent portion, having a first region above the bent portion and a second region below the bent portion.

[0252] Next, after filtering the liquid crystal alignment agent using a 1.0 μm filter, it was spin-coated onto the prepared electrode substrate (first glass substrate) and a glass substrate with an ITO film on the back side and columnar spacers with a height of 4 μm (second glass substrate). After drying on a heating plate at 80°C for 2 minutes, it was fired in a hot air circulating 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 pressure of 250–550 mJ / cm². 2 The exposure level is irradiated with linearly polarized ultraviolet light of wavelength 254nm, which has an extinction ratio of 10:1 or higher, through a polarizing plate. It should be noted that the liquid crystal alignment film formed on the first glass substrate is aligned such that the direction dividing the inner angle of the pixel bend is orthogonal to the alignment direction of the liquid crystal. The liquid crystal alignment film formed on the second glass substrate is aligned such that the alignment direction of the liquid crystal on the first glass substrate is consistent with the alignment direction of the liquid crystal on the second glass substrate when the liquid crystal cell is manufactured. The substrate is further fired in a hot air circulating oven at 230°C for 30 minutes to obtain a substrate with a liquid crystal alignment film. Using the two substrates as a group, a sealant is printed on the substrates. Another substrate is then bonded together with the liquid crystal alignment film surfaces facing each other and the alignment direction at 0°. The sealant is then cured to produce an empty cell. Liquid crystal MLC-3019 (manufactured by MERCK) is injected into the empty cell using a depressurized injection method, and the injection port is sealed to obtain an FFS-driven liquid crystal cell. Then, the obtained liquid crystal cell was heated at 110°C for 1 hour, left overnight, and then used for various evaluations.

[0253] [Evaluation of afterimages caused by long-term communication]

[0254] Using the aforementioned liquid crystal cell, an AC voltage of ±5V was applied at a frequency of 60Hz for 120 hours under a constant temperature environment of 60°C. Then, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited, and this state was maintained at room temperature for one day.

[0255] After one day, a liquid crystal cell is placed between two polarizing plates orthogonally aligned with their polarization axes. The backlight is then turned on without applying voltage, and the cell's orientation is adjusted to minimize the transmitted light brightness. The rotation angle Δ is calculated to determine when the liquid crystal cell rotates from the darkest angle in the second region of the first pixel to the darkest angle in the first region of the first pixel. The same angle Δ is calculated for the second pixel by comparing the second and first regions. The average angle Δ is then calculated using the angle Δ calculated for the first pixel and the angle Δ calculated for the second pixel.

[0256] <Evaluation Results>

[0257] The evaluation results related to the liquid crystal display elements obtained using the liquid crystal alignment agents (A1) to (A4) obtained in Examples 1 to 4 above and the liquid crystal display elements obtained using the liquid crystal alignment agents (B1) to (B4) obtained in Comparative Examples 1 to 4 above are shown in Table 2.

[0258] [Table 2]

[0259]

[0260] The liquid crystal alignment agents (A1) to (A2) obtained in Examples 1 and 2 showed less image retention due to long-term AC driving compared to the liquid crystal alignment agents (B1) and (B3) obtained in Comparative Examples 1 and 3. Furthermore, the liquid crystal alignment agents (A3) to (A4) obtained in Examples 3 and 4 showed less image retention due to long-term AC driving compared to the liquid crystal alignment agents (B2) and (B4) obtained in Comparative Examples 2 and 4.

[0261] Industrial availability

[0262] By using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film that suppresses image retention caused by long-term AC driving can be obtained in liquid crystal display elements using IPS and FFS driving methods. Therefore, its application in liquid crystal display elements requiring high display quality is expected.

[0263] Explanation of reference numerals in the attached figures:

[0264] 1: Lateral electric field liquid crystal display element; 2: Comb electrode substrate; 2a: Substrate; 2b: Linear electrode; 2c: Liquid crystal alignment film; 2d: Substrate; 2e: Surface electrode; 2f: Insulating film; 2g: Linear electrode; 2h: Liquid crystal alignment film; 3: Liquid crystal; 4: Opposite substrate; 4a: Liquid crystal alignment film; 4b: Substrate; L: Electric field line.

Claims

1. A liquid crystal aligning agent, characterized by, contains a polymer (A) which is at least one selected from the group consisting of a polyimide precursor having a repeating unit (a1) represented by the following formula (1) and a polyimide which is an imidized product of the polyimide precursor, in the formula (1), R1to R4each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, at least one of R1to R4represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group; R and Z each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Y1represents a divalent organic group represented by the following formula (H'), In formula (H'), R a1 ~R a3 each independently represents a hydroxyl group, a halogen atom, or a monovalent organic group having 1 to 3 carbon atoms, and in the case where a plurality of R a1 ~R a3 are present, each optionally is the same or different; L1 represents *1-O-C(=O)-*2 or *1-C(=O)-O-*2, in which *1 is bonded to a benzene ring optionally having a substituent R a1 , and *2 is bonded to a benzene ring optionally having a substituent R a2 ; L2 represents *2-O-C(=O)-*3 or *2-C(=O)-O-*3, in which *2 is bonded to a benzene ring optionally having a substituent R a2 in a para position to L1, and *3 is bonded to a benzene ring optionally having a substituent R a3 ; a1 to a3 are each independently an integer of 0 to 4, and satisfy a1+a2+a3≥1; * represents a bond.

2. The liquid crystal aligning agent according to claim 1, wherein the monovalent organic group in the formula (H') is an alkyl group having 1 to 3 carbon atoms, a haloalkyl group in which at least a part of hydrogen atoms in an alkyl group having 1 to 3 carbon atoms is substituted with a halogen atom, an alkoxy group having 1 to 3 carbon atoms, a haloalkoxy group in which at least a part of hydrogen atoms in an alkoxy group having 1 to 3 carbon atoms is substituted with a halogen atom, or an alkenyl group having 2 to 3 carbon atoms.

3. The liquid crystal aligning agent according to claim 1 or 2, wherein the divalent organic group represented by the formula (H') is a divalent organic group represented by any one of the following formulae (h-1) to (h-14), in the formulae (h-1) to (h-2) and (h-4) to (h-14), * represents a bonding bond.

4. The liquid crystal aligning agent according to claim 1 or 2, wherein the polymer (A) is at least one polymer selected from the group consisting of a polyimide precursor further having a repeating unit (a2) represented by the following formula (2) and a polyimide which is an imidized product of the polyimide precursor, in the formula (2), R1to R4, R, and Z have the same meanings as in the formula (1); Y2represents a divalent organic group represented by the following formula (O), *-Ar-Q2-Ar-* (O) In formula (O), each Ar independently represents a benzene ring, a biphenyl structure, or a naphthalene ring; any hydrogen atom on the benzene ring or naphthalene ring possessed by the Ar is optionally substituted with a halogen atom or a monovalent organic group; Q2 represents a group in which a part of a -(CH2) n - group is substituted with any of -0-, -C(=0)-, and -0-C(=0)-, the - (CH2) n - group, n is an integer of 2 to 18; and * represents a bond. n - group, n is an integer of 2 to 18; and * represents a bond.

5. The liquid crystal aligning agent according to claim 4, wherein the divalent organic group represented by the formula (O) is a divalent organic group represented by any one of the following formulae (o-1) to (o-14), in the formulae (o-1) to (o-14), * represents a bonding bond; in the formula (o-14), two m's are each independent.

6. The liquid crystal aligning agent according to claim 1 or 2, wherein the polymer (A) is at least one polymer selected from the group consisting of a polyimide precursor further having at least one selected from the group consisting of a repeating unit (a2') represented by the following formula (2') and a repeating unit (a3) represented by the following formula (3), and a polyimide which is an imidized product of the polyimide precursor, In formula (2') and formula (3), X 2’ and X3represents a tetravalent organic group, Y 2’ represents a divalent organic group represented by the following formula (02), Y3represents a divalent organic group having a group "-N(D)-" in the molecule, the number of carbon atoms other than D being 6 to 30, in the group "-N(D)-", D represents a carbamate-based protecting group; R and Z have the same meanings as in the formula (1), In formula (O2), Ar2' each independently represents a benzene ring, and any hydrogen atom on the benzene ring is optionally substituted with a halogen atom, an alkyl group having 1 to 3 carbon atoms, or a haloalkyl group having 1 to 3 carbon atoms; Q 2’ represents a single bond or -O-, and m represents an integer of 0 to 2; * represents a bond.

7. The liquid crystal aligning agent according to claim 6, wherein The polymer (A) contains the repeating unit (a1), the repeating unit (a2), and the repeating unit (a2') and their imidized structures in a total of 30 mol% or more of all repeating units.

8. The liquid crystal aligning agent according to claim 6, wherein The bivalent organic group represented by the formula (O2) is a bivalent organic group represented by any of the following formulas (o2-1) to (o2-12), In the formulas (o2-1) to (o2-12), * represents a bonding bond.

9. The liquid crystal aligning agent according to claim 1 or 2, wherein The polymer (A) contains the repeating unit (a1) and the imidized structure of the repeating unit (a1) in a total of 5 to 95 mol% of all repeating units.

10. The liquid crystal aligning agent according to claim 1 or 2, wherein The liquid crystal aligning agent is used for a liquid crystal aligning film for a photo-alignment process.

11. A liquid crystal aligning film obtained from the liquid crystal aligning agent according to any one of claims 1 to 10.

12. A liquid crystal display element comprising the liquid crystal aligning film according to claim 11.

13. A manufacturing method of a liquid crystal display element, comprising the following steps (1) to (3): Step (1): a step of applying the liquid crystal aligning agent according to any one of claims 1 to 10 to a substrate; Step (2): a step of baking the applied liquid crystal aligning agent; Step (3): a step of performing an alignment treatment on the film obtained in step (2).

14. The manufacturing method of a liquid crystal display element according to claim 13, wherein The alignment treatment is a photo-alignment treatment.

15. The manufacturing method of a liquid crystal display element according to claim 14, wherein The radiation exposure amount in the photo-alignment treatment is 100 to 1500 mJ / cm 2 .

16. The manufacturing method of a liquid crystal display element according to any one of claims 13 to 15, wherein The manufacturing method of a liquid crystal display element further comprises the following step (4), Step (4): a step of further performing a heat treatment at 50 to 300°C on the film subjected to the alignment treatment in step (3).

17. A liquid crystal display element obtained by the manufacturing method of a liquid crystal display element according to any one of claims 13 to 16.

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