Liquid crystal alignment agent, liquid crystal alignment film, liquid crystal display element, and method for manufacturing liquid crystal display element

Abstract

A liquid crystal alignment agent characterized by containing a polymer (A), the polymer (A) being selected from at least one of the group consisting of a polyimide precursor having a repeating unit (a1) represented by the following formula (1) and a polyimide that is a polyimide derivative of the polyimide precursor. In formula (1), X1 represents a tetravalent organogroup; Y1 is a divalent organogroup represented by the following formula (H) and having three or more benzene rings; *-Ar1-L1-A-L1'-Ar1'-* (H) In formula (H), A represents an alkyl group with 4 to 10 carbon atoms. Ar1 and Ar1' each independently represent a benzene ring, a biphenyl structure, or a naphthalene ring. Any hydrogen atom on the ring of Ar1 and Ar1' can also be substituted with a monovalent group.

Description

[Technical Field]

[0001] This invention relates to liquid crystal alignment agents, liquid crystal alignment films, and liquid crystal display elements. [Previous Technology]

[0002] Liquid crystal display devices have historically been widely used as display units in personal computers, smartphones, mobile phones, television receivers, and the like. A liquid crystal display device typically includes: a liquid crystal layer sandwiched between a display element substrate and a color filter substrate; pixel electrodes and a common electrode that apply an electric field to the liquid crystal layer; an alignment film that controls the alignment of the liquid crystal molecules in the liquid crystal layer; and thin-film transistors (TFTs) that switch the electrical signals supplied to the pixel electrodes. Known driving methods for liquid crystal molecules include: longitudinal electric field methods such as TN and VA methods; transverse 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 produced by a so-called tribological process, which involves rubbing the surface of a film made of polyamide and / or polyimide obtained by amide-modifying polyamide on an electrode substrate in one direction with a cloth such as cotton, nylon, or polyester. Tribological processing is a simple and highly productive industrially useful method. However, with the increasing performance, precision, and size of liquid crystal display elements, various problems such as surface scratches, dust generation, mechanical stress, and static electricity caused by tribological processing, as well as inhomogeneities within the alignment surface, have become apparent. As an alternative to tribological processing, photoalignment methods, which impart alignment capabilities to liquid crystals by irradiating them with polarized radiation, are known. Regarding photoalignment methods, methods utilizing photoisomerization reactions, photocrosslinking reactions, and photodecomposition reactions have been proposed (e.g., see Non-Patent Literature 1, Patent Literature 1, and Patent Literature 2). [Previous Technical Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. Hei 9-297313 [Patent Document 2] Japanese Patent Application Publication No. 2004-206091 [Non-Patent Document]

[0005] [Non-Patent Literature 1] "Liquid Crystal Photoalignment Film" Kitowaki, Ichimura, Functional Materials, November 1997, Vol.17, No.11, pp.13-22 [Summary of the Invention]

[0006] (The problem the invention aims to solve)

[0007] The liquid crystal alignment film used in the aforementioned IPS and FFS driving liquid crystal display elements requires high alignment control to suppress image retention (hereinafter also referred to as AC image retention) caused by long-term AC driving. Furthermore, when performing alignment processing using photoalignment, the amount of light irradiation becomes a factor affecting energy costs and production speed; therefore, it is preferable to perform alignment processing with a low amount of light irradiation. However, after review, the inventors of this invention discovered that the range of light irradiation for liquid crystal alignment films that achieve liquid crystal alignment with a low amount of light irradiation is narrow, resulting in a small variation (non-uniformity) in the torsion angle of the liquid crystal within the liquid crystal alignment film surface. Therefore, when achieving large-screen display of the liquid crystal display element, a portion of the obtained liquid crystal alignment film may become incompletely aligned. During long-term image display, there is a concern that the in-plane brightness may vary, leading to a decrease in display quality.

[0008] The object of the present invention is to provide a liquid crystal alignment agent that expands the range of light irradiation for obtaining a liquid crystal alignment film with small variation (non-uniformity) in the torsion angle of the liquid crystal within the liquid crystal alignment film surface, thereby enabling the efficient acquisition of a high-quality liquid crystal alignment film; the liquid crystal alignment film obtained by the liquid crystal alignment agent; and a liquid crystal display element using the liquid crystal alignment film. Furthermore, the object is to provide a liquid crystal alignment agent that expands the range of light irradiation for obtaining a liquid crystal alignment film that suppresses AC image retention, thereby enabling the efficient acquisition of a high-quality liquid crystal alignment film; the liquid crystal alignment film obtained by the liquid crystal alignment agent; and a liquid crystal display element using the liquid crystal alignment film. (Solution to the problem)

[0009] The inventors of this invention have made great efforts in research and have found that the above-mentioned problems can be solved by using a liquid crystal alignment agent containing specific components, thus completing the present invention. Specifically, the main points are as follows.

[0010] A liquid crystal alignment agent, characterized in that it contains a polymer (A), which is selected from at least one of the group consisting of a polyimide precursor having a repeating unit (a1) represented by the following formula (1) and a polyimide that is an imide derivative of the polyimide precursor.

[0011] [Chemical 1] In formula (1), X1 represents a tetravalent organogroup. Y1 is a divalent organogroup having three or more benzene rings, represented by the following formula (H). R and Z each independently represent a hydrogen atom or a monovalent organogroup. [Chemical 2] In formula (H), L1 and L1' each independently represent a single bond, -O-, -S-, -C(=O)-, -OC(=O)-, or -C(=O)-NR- (R represents a hydrogen atom or a monovalent organogroup). A represents an alkyl group having 4 to 10 carbon atoms. Ar1 and Ar1' each independently represent a benzene ring, a biphenyl structure, or a naphthalene ring. Any hydrogen atom on the rings of Ar1 and Ar1' can also be replaced by a monovalent group. Furthermore, throughout this specification, halogen atoms may include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc., and * indicates an atomic bond. (Effects of the Invention)

[0012] According to the present invention, a liquid crystal alignment agent that expands the range of light irradiation for obtaining a liquid crystal alignment film with small variation (non-uniformity) of the torsion angle of the liquid crystal within the liquid crystal alignment film surface, thereby enabling the efficient acquisition of a high-quality liquid crystal alignment film, the 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 obtained. Furthermore, a liquid crystal alignment agent that expands the range of light irradiation for obtaining a liquid crystal alignment film capable of suppressing AC image retention, thereby enabling the efficient acquisition of a high-quality liquid crystal alignment film, the 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 obtained.

Implementation Method

[0014] <Polymer (A)> The liquid crystal alignment agent of the present invention contains at least one polymer (A) selected from the group consisting of a polyimide precursor having a repeating unit (a1) represented by the following formula (1) and a polyimide that is a polyimide derivative of the polyimide precursor. Furthermore, the polymer (A) may be composed of one or more polymers.

[0015] [Chemical 3] In formula (1), X1 represents a tetravalent organogroup. Y1 is a divalent organogroup represented by the following formula (H) and having three or more benzene rings. R and Z each independently represent a hydrogen atom or a monovalent organogroup.

[0016] The polymer (A) preferably has a divalent organic group represented by the above formula (H) in the main chain direction of the polymer (A). Furthermore, the polymer (A) is more preferably equipped with a benzene ring possessed by Y1 in the main chain direction of the polymer (A). The main chain of the polymer refers to the portion composed of the longest atomic chain in the polymer. Moreover, "the polymer (A) has a divalent organic group represented by the above formula (H) in the main chain direction of the polymer (A)" means that the longest atomic chain of the divalent organic group represented by formula (H) constitutes the main chain of the polymer (A). In other words, "the polymer (A) has a divalent organic group represented by the above formula (H) in the main chain direction of the polymer (A)" means that the two ends of the longest atomic chain of the divalent organic group represented by formula (H) are respectively bonded to two nitrogen atoms bonded by Y1 in formula (1). Furthermore, it means that at least two carbon atoms of each benzene ring in all the benzene rings possessed by Y1 constitute the main chain of the polymer (A).

[0017] Here, the benzene ring "a divalent organogroup having three or more benzene rings" also includes the benzene ring constituting a condensation ring. When counting the number of benzene rings in formula (H), it is counted as follows: A naphthalene ring has two benzene rings. A biphenyl structure has two benzene rings. The number of benzene rings in Y1 is not particularly limited if it is three or more; for example, it can be three or more but less than eight, or three or more but less than six. From the viewpoint of ideally obtaining the effects of the present invention, it can also be four or more but less than six.

[0018] [Chemical 4] In formula (H), L1 and L1' each independently represent a single bond, -O-, -S-, -C(=O)-, -OC(=O)-, or -C(=O)-NR- (R represents a hydrogen atom or a monovalent organic group). A represents an alkyl group having 4 to 10 carbon atoms, more preferably an alkyl group having 4, 6, 8, or 10 carbon atoms, and even more preferably an alkyl group having 4 or 6 carbon atoms. Ar1 and Ar1' each independently represent a benzene ring, a biphenyl structure, or a naphthalene ring. Any hydrogen atom on the ring of Ar1 and Ar1' can also be replaced by a monovalent group.

[0019] The monovalent organic group of the "-C(=O)-NR-" group in L1 and L1' above can be an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, a cellulose group having 2 to 3 carbon atoms, an alkylsilyl group having 1 to 3 carbon atoms, an alkoxysilyl group having 1 to 3 carbon atoms, a tributoxycarbonyl group, or a monovalent organic group obtained by substituting a portion of the hydrogen atoms of such groups with at least one of a halogen atom and a hydroxyl group.

[0020] The substituents on any hydrogen atom of the rings of Ar1 and Ar1' in the above formula (H) are monovalent groups, which may include alkyl groups with halogen atoms, alkyl groups having 1 to 3 carbon atoms, and alkyl groups having 1 to 3 carbon atoms in which at least a portion of the hydrogen atoms are replaced by at least one of the above-mentioned halogen atoms and hydroxyl groups; alkoxy groups having 1 to 3 carbon atoms and alkoxy groups having 1 to 3 carbon atoms in which at least a portion of the hydrogen atoms are replaced by at least one of the above-mentioned halogen atoms and hydroxyl groups; alkenyl groups having 2 to 3 carbon atoms; acetylated groups having 2 to 3 carbon atoms; alkylsilyl groups having 1 to 3 carbon atoms; alkoxysilyl groups having 1 to 3 carbon atoms; hydroxyl groups; nitrile groups; etc.

[0021] If we take an ideal concrete example of the basis "*-L1-A-L1'-*" in the above formula (H), we can list: basis "*-(CH2)n-*", basis "*-O-(CH2)nO-*", basis "*-C(=O)-(CH2)nC(=O)-*", basis "*-C(=O)-NR-(CH2)nO-*", basis "*-OC(=O)-(CH2)nO-*", basis "*-OC(=O)-(CH2)nOC(=O)-*", basis "*-OC(=O)-(CH2)nC(=O)-O-*" The radicals "*-S-(CH2)nS-*", "*-C(=O)-NR-(CH2)n-NR-C(=O)-*", "*-C(=O)-O-(CH2)nOC(=O)-*", "*-O-(CH2)n-*", "*-S-(CH2)n-*", or "*-NR-C(=O)-(CH2)nC(=O)-NR-*" (R represents a hydrogen atom or a monovalent organic group, which can be exemplified by the structures shown by R in the radicals "-C(=O)-NR-" of L1 and L1' above.) Among these, from the viewpoint of ideally obtaining the effects of the present invention, the base "*-L1-A-L1'-*" is preferably "*-(CH2)n-*", "*-O-(CH2)nO-*", or "*-O-(CH2)n-*". n is an integer from 4 to 10, preferably an integer of 4, 6, 8, or 10, and more preferably an integer of 4 or 6.

[0022] Regarding Y1 in the above formula (1), from the viewpoint of ideally obtaining the effect of the present invention, it is preferable to use any of the following formulas (h-1) to (h-4) to represent a divalent organic group. [Chemical 5] In formulas (h-1) to (h-4), Ra1 to Ra4 represent monovalent organic groups. Specific examples can be listed as structures exemplified by substituents on the hydrogen atoms of the rings of Ar1 and Ar1' in the above formula (H). L represents the base "*-L1-A-L1'-*" in the above formula (H) (* represents an atomic bond). m are each an independent integer from 0 to 6, and n are each an independent integer from 0 to 4. When multiple Ra1 to Ra4 exist, they can be the same or different.

[0023] In the above formula (1), the monovalent organic groups of R and Z can be listed as: monovalent hydrocarbon groups with 1 to 20 carbon atoms, monovalent groups A formed by replacing the methylene group of the hydrocarbon group with -O-, -S-, -CO-, -COO-, -COS-, -NR3-, -CO-NR3-, -Si(R3)2- (where R3 is a hydrogen atom or a monovalent hydrocarbon group with 1 to 10 carbon atoms), -SO2-, etc., at least one of the hydrogen atoms bonded to the carbon atoms of the above monovalent hydrocarbon group or the above monovalent group A is replaced with a halogen atom, hydroxyl, alkoxy, nitro, amino, mercapto, nitroso, alkylsilyl, alkoxysilyl, silyl alcohol, sulfinic acid, phosphin, carboxyl, cyano, sulfonyl, acetyl, etc., and monovalent groups having heterocycles. In formula (1) above, the monovalent organic groups of R and Z are preferably alkyl groups with 1 to 10 carbon atoms, alkenyl groups with 2 to 10 carbon atoms, alkynyl groups with 2 to 10 carbon atoms, terbutoxycarbonyl groups, or 9-pyromethoxycarbonyl groups, with alkyl groups with 1 to 3 carbon atoms being more preferred, and methyl groups being even more preferred. Regarding R and Z, from the viewpoint of ideally obtaining the effects of the present invention, it is more ideal for each to be a hydrogen atom or an alkyl group with 1 to 3 carbon atoms, with hydrogen atoms or methyl groups being even more preferred.

[0024] Regarding the polymer (A) described above, from the viewpoint of ideally obtaining the effects of the present invention, at least one polymer may be selected from the group consisting of a polyimide precursor having a repeating unit (a2) represented by the following formula (2) and a polyimide consisting of a amide of the polyimide precursor. In other words, the polymer (A) described above may also have at least one of the repeating unit (a2) represented by the following formula (2) and the amide structure of the repeating unit (a2) represented by the following formula (2). Furthermore, the repeating unit (a2) may be composed of one or more types.

[0025] [Chemical 6] In formula (2), X2 represents a tetravalent organic group. Y2 represents a divalent organic group represented by the following formulas (o-1)~(o-14). R and Z are synonyms with R and Z in the above formula (1).

[0026] [Chemical 7][Chemical 8] In formulas (o-13) to (o-14), the two m are independent. Any hydrogen atom on the benzene ring, biphenyl structure, or naphthalene ring in formulas (o-1) to (o-14) can also be replaced by a monovalent group.

[0027] A substituent on any hydrogen atom of the benzene ring, biphenyl structure, or naphthalene ring in formulas (o-1) to (o-14) is a monovalent group, which can be listed as: alkyl groups in which at least a portion of the halogen atom, alkyl group with 1 to 3 carbon atoms, and hydrogen atoms are replaced by at least one of the above-mentioned halogen atom and hydroxyl group; alkoxy group with 1 to 3 carbon atoms and hydrogen atoms are replaced by at least one of the above-mentioned halogen atom and hydroxyl group; alkenyl group with 2 to 3 carbon atoms; acetylated group with 2 to 3 carbon atoms; alkylsilyl group with 1 to 3 carbon atoms, alkoxysilyl group with 1 to 3 carbon atoms, hydroxyl group, nitrile group, etc.

[0028] Regarding the polymer (A) described above, from the viewpoint of ideally obtaining the effects of the present invention, it is also possible to select at least one polymer from the group consisting of a polyimide precursor composed of at least one of a repeating unit (a2') represented by formula (2') and a repeating unit (a3) ​​represented by formula (3), and a polyimide composed of a amide of the polyimide precursor. In other words, the polymer (A) described above may also have at least one of the repeating unit (a2') represented by formula (2'), the amide structure of the repeating unit (a2') represented by formula (2'), the repeating unit (a3) ​​represented by formula (3), and the amide structure of the repeating unit (a3) ​​represented by formula (3). [Chemical Engineering 9] In formulas (2') and (3), X2' and X3 represent tetravalent organic groups, Y2' represents a divalent organic group represented by formula (O2), and Y3 represents a divalent organic group with 6 to 30 carbon atoms containing the group "-N(D)- (D represents a carbamate protecting group)". R and Z are synonyms with R and Z in formula (1) above. [Chemical Engineering 10] In formula (O2), m represents an integer from 0 to 2. When m is 0, Ar2' represents a benzene ring or a naphthalene ring. When m is 1 to 2, Ar2' independently represents a benzene ring. Any hydrogen atom on the ring of Ar2' can also be replaced by a monovalent group. The substituent can be listed in the structures exemplified by any hydrogen atom substituent of the benzene ring, biphenyl structure, or naphthalene ring in formulas (o-1) to (o-14). Q2' represents a single bond or -O-. When multiple Ar2' and Q2' exist, each Ar2' and Q2' can be the same or different.

[0029] Regarding the divalent organic group represented by (O2) in the above formula, considering the low occurrence of AC residue, the following are selected: p-phenylenediamine, m-phenylenediamine, 2,5-diaminotoluene, 2,5-diaminop-xylene, 1,4-diaminotrimethylbenzene, 1,4-diaminotetramethylbenzene, 1,4-diamino-2,5-methoxybenzene, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 2,2'-dimethoxy-4,4'-diaminobiphenyl, In the group consisting of biphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 2,2'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3-trifluoromethyl-4,4'-diaminobiphenyl, 2-trifluoromethyl-4,4'-diaminobiphenyl, 3-fluoro-4,4'-diaminobiphenyl, 2-fluoro-4,4'-diaminobiphenyl, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 2,6-diaminonaphthalene, and 1,5-diaminonaphthalene, the diamines are preferably divalent organogroups with two amino groups removed.

[0030] The D in Y3 above represents a carbamate protecting group, such as a tributoxycarbonyl or 9-pyromethoxycarbonyl. Specific examples of Y3 above can be listed below, represented by a divalent organic group as shown in formula (Dx).

[0031] [Chemical 11]

[0032] In formula (Dx), Q5 represents a single bond, -(CH2)n- (n is an integer from 1 to 20), or any -CH2- of -(CH2)n- is substituted by -O-, -Si(CH3)2-, -COO-, -OCO-, -NQ9-, -NQ9CO-, -CONQ9-, -NQ9CONQ10-, -NQ9COO-, or -OCOO-, where Q9 and Q10 each independently represent a hydrogen atom or a monovalent organic group; Q6 and Q7 each independently represent -H, -NHD, -N(D)2, a group having -NHD, or a group having -N(D)2 (D represents a carbamate protecting group). However, when m = 0, Q6 has a carbamate protecting group, and when m = 1, at least one of Q5, Q6, and Q7 has a carbamate protecting group in its radical. Furthermore, Q6 and Q7 represent groups other than hydrogen atoms, with an ideal carbon number of 1 to 8. Examples of monovalent organogroups in Q9 and Q10 include alkyl groups with 1 to 3 carbon atoms, alkenyl groups with 2 to 3 carbon atoms, alkynyl groups with 2 to 3 carbon atoms, and monovalent organogroups with 1 to 3 carbon atoms containing fluorine atoms.

[0033] For an ideal concrete example of Y3, considering the viewpoint of minimal AC afterimage, any of the following formulas (Y3-1) to (Y3-9) can be used to represent a divalent organic group. "Boc" represents a third butoxycarbonyl group.

[0034] [Chemical 12]

[0035] For X1, X2, X2', and X3 mentioned above, examples of tetravalent organic groups derived from acyclic aliphatic tetracarboxylic dianhydrides or their derivatives, alicyclic tetracarboxylic dianhydrides or their derivatives, or aromatic tetracarboxylic dianhydrides or their derivatives can be listed. Examples of tetracarboxylic dianhydride derivatives include tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters, and tetracarboxylic acid dialkyl ester dihalides. It is more desirable for tetravalent organic groups derived from tetracarboxylic dianhydrides or their derivatives to have at least one substructure selected from the group consisting of cyclobutane ring structures, cyclopentane ring structures, and cyclohexane ring structures. Ideal specific examples of X1, X2, X2', and X3 include, in addition to the tetravalent organic group represented by formula (g) below, any of the tetravalent organic groups represented by formulas (X-1) to (X-25) below, and tetravalent organic groups derived from aromatic tetracarboxylic dianhydrides. From the viewpoint of ideally obtaining the effects of the present invention, it is preferable that X1, X2, X2' and X3 are tetravalent organic groups represented by the following formulas (g), (X-1)~(X-5), (X-11), (X-21)~(X-23), and it is even more preferable that the tetravalent organic group is represented by the following formula (g).

[0036] [Chemical 13] In formula (g), R1 to R4 each 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, and at least one of R1 to R4 represents a group other than a hydrogen atom as defined above.

[0037] [Chemistry 14][Chemistry 15]

[0038] Specific examples of alkyl groups having 1 to 6 carbon atoms in R1 to R4 of the above formula (g) include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, etc. Specific examples of alkenyl groups having 2 to 6 carbon atoms in R1 to R4 include vinyl, propenyl, butynyl, etc., which can be linear or branched. Specific examples of alkynyl groups having 2 to 6 carbon atoms in R1 to R4 include 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. A more ideal combination of R1 to R4, considering high photoreactivity, would be where R1 to R4 are hydrogen atoms or methyl atoms, with at least one of R1 to R4 being methyl, and at least two of R1 to R4 being methyl. Even more desirable is a configuration where R1 and R4 are methyl atoms and R2 and R3 are hydrogen atoms.

[0039] Here, aromatic tetracarboxylic acid dianhydrides refer to acid dianhydrides obtained by intramolecular dehydration of the carboxyl groups bonded to aromatic rings such as benzene rings and naphthalene rings. For specific examples, any one of the following formulas (Xa-1) to (Xa-2) can be listed as a tetravalent organic group, and any one of the following formulas (Xr-1) to (Xr-7) can be listed as a tetravalent organic group.

[0040] [Chemical 16] In formulas (Xa-1) and (Xa-2), x and y are each independently a single bond, ether, carbonyl, ester, alkyldiyl with 1 to 10 carbon atoms, 1,4-phenylene, sulfonyl or amide bond. j and k are integers of 0 or 1.

[0041] [Chemical 17]

[0042] The tetravalent organic group represented by the above formula (Xa-1) or (Xa-2) can also be represented by any of the following formulas (Xa-3) to (Xa-19).

[0043] [Chemical 18]

[0044] [Chemical 19]

[0045] 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 (a1), repeating unit (a2), repeating unit (a2'), and repeating unit (a3) ​​and having a repeating unit (a4) represented by the following formula (4) and a polyimide consisting of a polyimide of the polyimide precursor.

[0046] [Chemical 20]

[0047] In formula (4), X4 represents a tetravalent organic group, Y4 represents a divalent organic group represented by formula (H) above, a divalent organic group represented by formulas (o-1) to (o-14) above, a divalent organic group with 6 to 30 carbons having the above-mentioned group "-N(D)- (D represents a carbamate protecting group)", and a divalent organic group other than the divalent organic group represented by formula (O2) above. R and Z are synonyms with R and Z in formula (1) above.

[0048] Specific examples of X4 can be listed in the descriptions of X1, X2, X2', and X3 above, which illustrate the tetravalent organic groups. From the viewpoint of ideally obtaining the effects of the present invention, it is more ideal for X4 to be a tetravalent organic group represented by formula (g) above, or a tetravalent organic group represented by any of formulas (X-1) to (X-25) above, and even more preferred are tetravalent organic groups represented by formulas (g), (X-1) to (X-5), (X-11), and (X-21) to (X-23) above, with the tetravalent organic group represented by formula (g) above being even more preferred.

[0049] Y4 represents the divalent organic group represented by formula (H) above, the divalent organic group represented by formulas (o-1) to (o-14) above, the divalent organic group with 6 to 30 carbons having the above-mentioned group "-N(D)- (D represents a carbamate protecting group)", and the divalent organic group other than the divalent organic group represented by formula (O2) above (hereinafter also referred to as other divalent organic groups). The other divalent organic groups can be listed as divalent organic groups from which two amino groups have been removed from the following diamines. Examples include diamines with photoalignment groups, such as 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, and 3,3'-dimethyl-4,4'-diaminodiphenylmethane; diamines represented by formulas (g-1) to (g-10) with photoalignment groups; diamines represented by formulas (u-1) to (u-3) with urea bonds (but these diamines do not have carbamate protecting groups in the molecule); and diamines represented by formulas (u-4) to (u-8) with amide bonds (but these diamines do not have carbamate protecting groups in the molecule). Amines do not have intramolecular carbamate protecting groups. They are structures consisting of at least one nitrogen-containing group from the group consisting of a nitrogen-containing heterocycle and an amino group represented by the radical "*21-NR-*22" (*21 and *22 represent atomic bonds to the carbon atoms constituting the aromatic ring. However, the carbon atom does not form a ring with the nitrogen atom bonded to R. R represents a hydrogen atom or a monovalent organic group, wherein the monovalent organic group is bonded to the nitrogen atom by a carbon atom other than the carbonyl carbon). (Hereinafter also referred to as nitrogen-containing structures.)) of diamines; 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol; 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 4,4'-diaminodiphenylethane-3-carboxylic acid, 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid, 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, 3,3'-diaminobiphenyl-4,4'-dicarboxylic acid, 3,3'-diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid Diamines containing carboxyl groups, such as phenylmethane-3,3'-dicarboxylic acid, 4,4'-diaminodiphenylethane-3,3'-dicarboxylic acid, and 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid; 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 4,4'-diaminodiphenyl ketone, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-dihydroindene-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4- Diamines with photopolymerizable groups at the end, such as diamino-N,N-diallylaniline; diamines with a steroid skeleton, such as cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanosterol 3,5-diaminobenzoate, and 3,6-bis(4-aminobenzoyloxycholestan); diamines represented by formulas (V-1) to (V-6); and diamines with siloxane bonds, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane. The following are diamines having an acezoline ring structure, such as (Ox-1) to (Ox-2); diamines having free radical polymerization initiator functions, such as 1-(4-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone, 2-(4-(2-hydroxy-2-methylpropionic)phenoxy)ethyl-3,5-diaminobenzoate, 4,4'-diaminodiphenyl ketone, 3,3'-diaminodiphenyl ketone, etc., with the removal of two amino groups, and a divalent organic group represented by any one of the formulas (Y-1) to (Y-167) as described in WO2018 / 117239.

[0050] [Chemistry 21][Chemistry 22][Chemistry 23]

[0051] In the above formulas (V-1) to (V-6), Xv1 to Xv4 and Xp1 to Xp2 each independently represent -(CH2)a- (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-, and Xv5 represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. Xa represents single bonds, -O-, -NH-, -O-(CH2)mO- (m represents an integer from 1 to 6), -C(CH3)2-, -CO-, -(CH2)m- (m represents an integer from 1 to 6), -SO2-, -OC(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). The following are integers: -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). Rv1 to Rv4 and R1a to R1b each independently represent an alkyl group with 1 to 20 carbon atoms, an alkoxy group with 1 to 20 carbon atoms, or an alkoxyalkyl group with 2 to 20 carbon atoms.

[0052] [Chemical 24]

[0053] The above-mentioned nitrogen-containing heterocycles include, for example: pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyrazine, pyridine, indole, benzimidazole, purine, quinoline, isoquinoline, acetidine, quinoline, phthaloline, triazine, carbazole, acridine, piperidine, piperidine, pyrrolidine, hexamethyleneimine, etc. Among them, pyridine, pyrimidine, pyridine, piperidine, piperidine, quinoline, carbazole, or acridine are preferred.

[0054] The monovalent organogroup R in the above-mentioned group "*21-NR-*22" represents a monovalent hydrocarbon group with 1 to 10 carbon atoms, a monovalent group formed by inserting -O- or -C(=O)- between carbon-carbon bonds of the hydrocarbon group, or a monovalent organogroup in which a portion of the hydrogen atoms of the above-mentioned hydrocarbon group and the above-mentioned monovalent group are replaced by halogen atoms or hydroxyl groups. R is preferably a hydrogen atom or a methyl group.

[0055] 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-13). [Chemical 25][Chemical 26][Chemical 27]

[0056] From the viewpoint of ideally obtaining the effects of the present invention, it is preferable that the aforementioned other divalent organogroups are divalent organogroups without a side chain structure having 4 or more carbon atoms. Examples of divalent organogroups without a side chain structure having 4 or more carbon atoms include: divalent organogroups from which two amino groups have been removed from the following diamines, namely, 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,N-diallyl aniline, and the above-mentioned diamines having a steroidal structure. The diamines in the group consisting of diamines with the alcohol skeleton, diamines represented by formulas (V-1) to (V-6), 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone, 2-(4-(2-hydroxy-2-methylpropionic)phenoxy)ethyl-3,5-diaminobenzoate, N-phenyl-3,6-diaminocarbazole, and diamines represented by (z-4) and (z-6) are divalent organic groups with two amino groups removed.

[0057] From the viewpoint of ideally obtaining the effects of the present invention, in polymer (A), the total content of the repeating unit (a1) and the amide structure of the repeating unit (a1) is preferably 5 to 100 mol%, and more preferably 10 to 100 mol%, of all repeating units. Furthermore, this total also includes the case where either the repeating unit (a1) or the amide structure of the repeating unit (a1) is 0 mol%. The term "total" here also includes the case where one or more constituent elements are 0 mol%. When polymer (A) contains repeating units other than the repeating unit (a1) and the amide structure of the repeating unit (a1), in polymer (A), the total content of the repeating unit (a1) and the amide structure of the repeating unit (a1) is preferably 95 mol% or less of all repeating units, more preferably 90 mol% or less, and even more preferably 80 mol% or less.

[0058] From the viewpoint of ideally obtaining the effects of the present invention, in polymer (A), the total content of the repeating unit (a2) and the amide structure of the repeating unit (a2) is preferably 5 mol% or more of all repeating units, more preferably 10 mol% or more, and even more preferably 20 mol% or more. Furthermore, the upper limit is preferably 90 mol% and more preferably 85 mol%.

[0059] From the viewpoint of ideally obtaining the effects of the present invention, in polymer (A), the total content of repeating units (a1) and repeating units (a2) and their amide structures is preferably 10 mol% or more of all repeating units, and more preferably 20 mol% or more. When polymer (A) contains repeating units other than repeating units (a1) and repeating units (a2) and their amide structures, the upper limit of the total content of repeating units (a1) and repeating units (a2) and their amide structures is preferably 95 mol%, and more preferably 90 mol%.

[0060] When polymer (A) contains at least one of repeating unit (a2') and amide-imide structures of repeating unit (a2'), from the viewpoint of ideally obtaining the effects of the present invention, the total content of repeating unit (a2') and amide-imide structures of repeating unit (a2') in polymer (A) is preferably 1 to 50 mol% of all repeating units, more preferably 1 to 40 mol%, and even more preferably 1 to 30 mol%. When polymer (A) contains at least one of repeating unit (a1) and its amide-imide structure, and at least one of repeating unit (a2') and its amide-imide structure, the lower limit of the total content of repeating unit (a1) and repeating unit (a2') and their amide-imide structures is preferably 5 mol%, and more preferably 10 mol%. From the viewpoint of ideally achieving the effects of the present invention, the polymer (A) contains at least one of repeating units (a1) and their amide structures, at least one of repeating units (a2) and their amide structures, and at least one of repeating units (a2') and their amide structures, and the total content of repeating units (a1), (a2), and (a2') and their amide structures is preferably 30 mol% or more, and more preferably 40 mol% or more of all repeating units. When the polymer (A) contains repeating units other than repeating units (a1), (a2), and (a2') and their amide structures, the maximum total content of repeating units (a1), (a2), and (a2') and their amide structures is preferably 95 mol%, and more preferably 90 mol%.

[0061] When the polymer (A) contains at least one of the repeating unit (a3) ​​and the amide structure of the repeating unit (a3), from the viewpoint of ideally obtaining the effects of the present invention, the total content of the repeating unit (a3) ​​and the amide structure of the repeating unit (a3) ​​in the polymer (A) is preferably 1 to 40 mol% of all repeating units, more preferably 1 to 30 mol%, and even more preferably 1 to 25 mol%.

[0062] The polymer (A) may also contain at least one of repeating units (a2') and repeating units (a3) ​​and their amide structures.

[0063] <Polymer (B)> 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) and its amide structure in the molecule. Furthermore, the polymer (B) may be composed of one or more types. From the viewpoint of ideally obtaining the effects of the present invention, polymers (B) may include polymers having repeating units or their amide structures represented by the following formula (5). Furthermore, the repeating units or their amide structures constituting the polymer (B) may be composed of one type or two or more types. [Chemical 28] In formula (5), X5 is a tetravalent organic group and Y5 is a divalent organic group. R and Z are synonyms with R and Z in the above formula (1).

[0064] The tetravalent organogroup of X5 mentioned above can be exemplified by a tetravalent organogroup derived from acyclic aliphatic tetracarboxylic dianhydrides or their derivatives, a tetravalent organogroup derived from alicyclic tetracarboxylic dianhydrides or their derivatives, or a tetravalent organogroup derived from aromatic tetracarboxylic dianhydrides or their derivatives. Specific examples include the tetravalent organogroup exemplified in X1 above. From the viewpoint of ideally achieving the effects of the present invention, among the aforementioned acyclic aliphatic or alicyclic tetracarboxylic dianhydrides or their derivatives, those having at least one substructure selected from the group consisting of cyclobutane ring structures, cyclopentane ring structures, and cyclohexane ring structures are preferred, considering their high effect on improving liquid crystal alignment. More ideally, X5 can be a tetravalent organogroup represented by formula (g) above, a tetravalent organogroup represented by any of formulas (X-1) to (X-25) above, a tetravalent organogroup represented by formulas (Xa-1) to (Xa-2) above, or a tetravalent organogroup represented by formulas (Xr-1) to (Xr-7) above (these are also collectively referred to as specific tetravalent organogroups.)

[0065] Regarding polymer (B), from the viewpoint of ideally obtaining the effects of the present invention, the content of the repeating unit or its amide structure represented by formula (5) of the specific tetravalent organic group described above is preferably 5 mol% or more of all repeating units contained in polymer (B), and more preferably 10 mol% or more.

[0066] The divalent organic groups of Y5 mentioned above can be exemplified by the divalent organic groups of Y4 mentioned above. Considering the viewpoint of minimal residual DC, polymer (B) is preferably a polymer containing the repeating unit or its amide-modified structure of Y5, derived from the above-mentioned diamines having urea bonds, the above-mentioned diamines having amide bonds, the above-mentioned diamines having nitrogen-containing structures, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, the above-mentioned diamines having carboxyl groups, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, p-phenylenediamine, and m-phenylenediamine, after removing two amine groups (these are also collectively referred to as specific divalent organic groups).

[0067] Regarding the polymer (B), from the viewpoint of improving transmittance, it is preferable to have two or more repeating units or their amide-imide structures represented by the above formula (5), and to contain at least one of the repeating units and their amide-imide structures represented by formula (5) which are divalent organic groups (i.e., Y5) from the above-mentioned diamine with urea bonds, diamine with amide bonds, or diamine with nitrogen-containing structures, having removed two amino groups, and to have at least one of the repeating units and their amide-imide structures represented by formula (5) which are divalent organic groups (i.e., Y5) from other diamines, having removed two amino groups.

[0068] Regarding polymer (B), considering the minimal residual DC, Y5 is the total content of the repeating unit represented by formula (5) of the specific divalent organic group mentioned above and its amide structure, which may be 1 mol% or more of all repeating units contained in polymer (B), or 5 mol% or more. More preferably, it is 10 mol% or more, and even more preferably 20 mol% or more.

[0069] Considering the view that there is less residual image from residual DC, the content ratio of polymer (A) and polymer (B) in the liquid crystal alignment agent can be 10 / 90~90 / 10, 20 / 80~90 / 10, or 20 / 80~80 / 20 by mass ratio of [polymer (A)] / [polymer (B)].

[0070] <Method for manufacturing polyamide, polyamide ester and polyimide> The polyamide ester, which is a polyimide precursor, and the polyamide and polyimide, which are polyimide derivatives, used in this invention can be synthesized, for example, by a known method as described in WO2013 / 157586.

[0071] More specifically, this is carried out by reacting the diamine component and the tetracarboxylic acid derivative component in a solvent via a (condensation polymerization) reaction. Examples of the aforementioned tetracarboxylic acid derivative component include tetracarboxylic dianhydride and its derivatives (tetracarboxylic acid dihalides, tetracarboxylic acid diesters, or tetracarboxylic acid diester dihalides). When one part of polymer (A) or (B) contains an acetic acid structure, for example, a polymer having an acetic acid structure (polyacetic acid) is obtained by reacting the tetracarboxylic acid dianhydride component with the diamine component. There are no particular limitations on the solvent, as long as it is a solvent that the resulting polymer can dissolve. Specific examples of the aforementioned solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolidinedione. Furthermore, when the polymer has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or solvents represented by the following formulas [D-1] to [D-3] can be used. [Chemical 29] In formula [D-1], D1 represents an alkyl group having 1 to 3 carbon atoms; in formula [D-2], D2 represents an alkyl group having 1 to 3 carbon atoms; and in formula [D-3], D3 represents an alkyl group having 1 to 4 carbon atoms.

[0072] These solvents can be used alone or in combination. Furthermore, even solvents insoluble in the polymer can be mixed with the above solvents and used as long as the resulting polymer does not precipitate. When the diamine component reacts with the tetracarboxylic acid derivative component in the solvent, the reaction can be carried out at any concentration, preferably 1-50% by mass, more preferably 5-30% by mass. The reaction can initially proceed at a high concentration, followed by the addition of solvent. During the reaction, the ratio of the total moles of the diamine component to the total moles of the tetracarboxylic acid derivative component is preferably 0.8-1.2. Similar to conventional condensation polymerization reactions, the closer this mole ratio is to 1.0, the larger the molecular weight of the resulting polymers (A) and (B).

[0073] Polyamide esters can be obtained by known methods such as: [I] reacting polyamide obtained by the above method with an esterifying agent, [II] reacting tetracarboxylic acid diester with diamine, [III] reacting tetracarboxylic acid diester dihalide with diamine, etc.

[0074] Methods for obtaining polyimide include known methods such as thermal amide formation by directly heating a solution of the polymer obtained by the above reaction, or catalytic amide formation by adding a catalyst to a solution of the polymer.

[0075] The polyimide in polymers (A) and (B) of the present invention is a partially or completely closed-ring repeating unit of the aforementioned polyimide precursor. The polyimide has a preferred imidization rate of 20-95%, more preferably 30-95%, and even more preferably 50-95%.

[0076] <Solution Viscosity and Molecular Weight of Polymers> The polyamides, polyamide esters, and polyimides used in this invention are ideal from a workability point of view when prepared as solutions with a concentration of 10-15% by mass, for example, having a solution viscosity of 10-1000 mPa·s, but there are no particular limitations. Furthermore, the solution viscosity (mPa·s) of the aforementioned polymers is the value measured at 25°C using an E-type rotational viscometer when a polymer solution with a concentration of 10-15% by mass is prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). The weight-average molecular weight (Mw) of the aforementioned polyamides, polyamide esters, and polyimides, as determined by gel permeation chromatography (GPC), converted from polystyrene, is preferably 1,000-500,000, more preferably 2,000-300,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number average molecular weight (Mn) of polystyrene measured using GPC, is preferably 15 or less, and more preferably 10 or less. Within this molecular weight range, good alignment and stability of the liquid crystal display element can be ensured.

[0077] <End-capping agent> When synthesizing the polymers (A) and (B) of the present invention, the tetracarboxylic acid derivative component and the diamine component as described above, as well as a suitable end-capping agent, can be used to synthesize end-sealed polymers. End-sealed polymers have the effect of increasing the film hardness of the liquid crystal alignment film obtained from the coating and improving the adhesion properties between the sealant and the liquid crystal alignment film. The ends of the polymers (A) and (B) of the present invention are, for example, amino groups, carboxyl groups, anhydride groups, or groups derived from the end-capping agent described later. Amine groups, carboxyl groups, and anhydride groups can be obtained by conventional condensation reactions or by sealing the ends using the end-capping agent described below.

[0078] End-capping agents, such as: acetic anhydride, maleic anhydride, naphthalic anhydride, phthalic anhydride, itaconic anhydride, 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.; dibutyl dicarbonate, diallyl dicarbonate, etc.; chlorocarbonyl compounds such as acrylonitrile chloride, methacrylamide chloride, nicotinamide chloride, etc.; benzene Monoamine compounds such as amines, 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, naphthyl isocyanate, 2-acryloyloxyethyl isocyanate, and 2-methacryloyloxyethyl isocyanate; and isothiocyanate compounds such as ethyl isothiocyanate and allyl isothiocyanate.

[0079] The ideal ratio of the capping agent to the total 100 moles of diamine used is 0.01 to 20 moles, and even more ideal is 0.01 to 10 moles.

[0080] <Liquid Crystal Orientation Agent> The liquid crystal orientation agent of the present invention contains polymer (A) and, if necessary, polymer (B). In addition to polymer (A) and polymer (B), the liquid crystal orientation agent of the present invention may also contain other polymers. Specific examples of other polymers include polymers selected from the group consisting of polysiloxanes, polyesters, polyamides, polyureas, polyurethanes, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-maleic anhydride) copolymers, poly(isobutylene-maleic anhydride) copolymers, poly(vinyl ether-maleic anhydride) copolymers, poly(styrene-phenylmaleimide) derivatives, and poly(meth)acrylates. Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, 2000, 3000 (manufactured by Cray Valley), and GSM301 (manufactured by GIFUSHELLAC). Specific examples of poly(isobutylene-maleic anhydride) copolymers include ISOBAM-600 (manufactured by Kuraray). Specific examples of poly(vinyl ether-maleic anhydride) copolymers include Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by ASHLAND). Other polymers can be used alone or in combination. Ideally, the proportion of other polymers relative to the total polymer content in the liquid crystal alignment agent should be less than 90 parts by weight, 10-90 parts by weight is better, and 20-80 parts by weight is even better.

[0081] The liquid crystal alignment agent is used to produce a liquid crystal alignment film. Considering the formation of a uniform thin film, it is preferably in the form of a coating solution. The liquid crystal alignment agent of this invention is also preferably a coating solution containing the aforementioned polymer component and organic solvent. In this case, the concentration of the polymer in the liquid crystal alignment agent can be appropriately varied depending on the desired coating thickness. Considering the formation of a uniform and defect-free coating, a polymer concentration of 1% by mass or more in the liquid crystal alignment agent is ideal; considering the storage stability of the solution, 10% by mass or less is preferred. Particularly, an ideal polymer concentration is 2 to 8% by mass.

[0082] The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as the polymer components can be uniformly dissolved. Specific examples include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N,N-dimethylpropionic acid, tetramethylurea, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinedione, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropanediamide, 3-butoxy 3-methyl-N,N-dimethylpropanediolamine, 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, and N-cyclohexyl-2-pyrrolidone (these are also collectively referred to as "good solvents"). Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanediolamine, 3-butoxy-N,N-dimethylpropanediolamine, or γ-butyrolactone are preferred. The content of 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 especially preferably 30-80% by mass.

[0083] Furthermore, the organic solvent contained in the liquid crystal alignment agent should preferably be a mixed solvent, in addition to the solvents mentioned above, that improves the coatability and surface smoothness of the coating film during liquid crystal alignment agent application (also known as a poor solvent). The content of the poor solvent is ideally 1-80% by mass of the total solvents contained in the liquid crystal alignment agent, more preferably 10-80% by mass, and especially preferably 20-70% by mass. The type and content of the poor solvent can be appropriately selected according to the coating equipment, coating conditions, and coating environment of the liquid crystal alignment agent. Specific examples of the poor solvents used are as follows, but are not limited to these. Examples include: diisopropyl ether, diisobutyl ether, diisobutylmethanol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propyl carbonate, ethyl carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy) 1-Propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, cyclohexyl acetate, 4-methyl-2-pentyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0084] Among them, it is preferable to use 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.

[0085] Ideal solvent combinations of good and bad solvents include: N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone with propylene glycol diacetate, N,N-dimethyllactamine with diisobutyl ketone, N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate, N-ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate, N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate and dipropylene glycol monobutyl ether. Methyl ether, N-ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether acetate, N-ethyl-2-pyrrolidone with dipropylene glycol dimethyl ether, N,N-dimethyllactamine with ethylene glycol monobutyl ether, N,N-dimethyllactamine with propylene glycol diacetate, N-ethyl-2-pyrrolidone with diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone with diethylene glycol monoethyl ether and butyl ceroxose acetate, N-methyl-2-pyrrolidone with diethylene glycol monomethyl ether and butyl ceroxose acetate, N,N-Dimethyllactic acid with diethylene glycol diethyl ether, N-Methyl-2-pyrrolidone with γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with diethylene glycol diethyl ether, N-Ethyl-2-pyrrolidone with N-Methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone, N-Ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol monobutyl ether, N-Methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with diisobutyl ketone, N-Methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with dipropylene glycol monomethyl ether, N-Methyl-2-pyrrolidone with 4-Hydroxy-4-methyl-2-pentanone with propylene glycol monobutyl ether, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol diacetate, N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with dipropylene glycol dimethyl ether, γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with diisobutyl ketone, γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol diacetate, N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether with diisobutyl ketone, N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether with diisopropyl ether, N-methyl N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether and diisobutylmethanol, N-methyl-2-pyrrolidone with γ-butyrolactone with dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone with propylene glycol monobutyl ether and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone with diethylene glycol diethyl ether and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether and propylene glycol diacetate, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether and diisobutyl ketone, N-ethyl-2-pyrrolidone with γ-butyrolactone and diisobutyl ketone Ketones, N-ethyl-2-pyrrolidone and N,N-dimethyllactamine and diisobutyl ketone, N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate, γ-butyrolactone and ethylene glycol monobutyl ether acetate and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate and propylene glycol dimethyl ether, N-methyl-2-pyrrolidone and 4-methyl-2-pentyl acetate and ethylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and cyclohexyl acetate and diacetone alcohol cyclohexanone and propylene glycol monomethyl ether, cyclopentanone and propylene glycol monomethyl ether, N-methyl-2-pyrrolidone and cyclohexanone and propylene glycol monomethyl ether, etc.

[0086] The liquid crystal alignment agent of the present invention may also additionally contain components other than polymer components and organic solvents (hereinafter also referred to as additive components). 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); compounds for promoting amide imidization; dielectrics and conductive materials for adjusting the dielectric constant and resistance of the liquid crystal alignment film.

[0087] Regarding the above-mentioned crosslinking compounds, considering the viewpoint that they exhibit good resistance to AC image retention and high film strength improvement, at least one compound selected from the group consisting of: compounds having at least one group selected from the group consisting of ethylene oxide, propylene oxide, protected isocyanate group, protected isothiocyanate group, group containing acezoline ring structure, group containing Meldrum's acid structure, cyclic carbonate group and hydroxyalkylamide bond, and phenolic compounds having at least one of alkoxymethyl and hydroxymethyl.

[0088] Specific examples of compounds containing ethylene oxide include: ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromonepentyl glycol diglycidyl ether, 1,3,5,6-tetracyclooxypropyl-2,4-hexanediol, bisphenol A type epoxy resins such as EPIKOTE 828 (manufactured by Mitsubishi Chemical Corporation), and EPIKOTE 8... 07 (Mitsubishi Chemical Corporation) and other bisphenol F type epoxy resins, YX-8000 (Mitsubishi Chemical Corporation) and other hydrogenated bisphenol A type epoxy resins, YX6954BH30 (Mitsubishi Chemical Corporation) and other epoxy resins containing a biphenyl backbone, EPPN-201 (Nippon Kayaku Co., Ltd.) and other phenolic varnish type epoxy resins, EOCN-102S (Nippon Kayaku Co., Ltd.) and other (ortho, meta, para) cresol varnish type epoxy resins, TEPIC (Nissan Chemical Co., Ltd.) and other trichloropropylene isocyanate, CELLOXIDE 2021P (made by Daicel Chemical Industry Co., Ltd.) and other alicyclic epoxy resins, N,N,N',N'-tetracyclooxypropylmethylenediamine, 1,3-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane, tetra(epoxypropoxymethyl)methane.

[0089] Specific examples of compounds containing propylene oxide include compounds containing two or more propylene oxide molecules as described in paragraphs

[0170] to

[0175] of WO2011 / 132751.

[0090] 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, compounds having three or more protected isocyanate groups as described in paragraphs

[0119] to

[0120] of WO2015 / 141598, and commercially available products such as CORONATE AP Stable M, CORONATE2503, 2515, 2507, 2513, 2555, MILLIONATE MS-50 (all manufactured by Tosoh Corporation), TAKENATE B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals Corporation), etc.

[0091] 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. Specific examples of compounds having a group containing an acezoline ring structure include compounds having two or more acezoline ring structures as described in paragraph

[0115] of Japanese Patent Application Publication No. 2007-286597. Specific examples of compounds having a group containing a Michaelis acid structure include compounds having two or more Michaelis acid structures as described in Publication No. WO2012 / 091088. Specific examples of compounds having cyclic carbonate groups include compounds described in Publication No. WO2011 / 155577.

[0092] Specific examples of the compounds having hydroxyalkylamide bonds mentioned above can be cited as compounds having two or more groups represented by the following formula (d) as described in paragraph

[0058] of Japanese Patent Application Publication No. WO2015 / 072554, Japanese Patent Application Publication No. 2016-118753, and compounds described in Japanese Patent Application Publication No. 2016-200798. [Chemical 30] R2 and R3 are each independently hydrogen atoms, alkyl groups having 1 to 3 carbon atoms, or "*-CH2-OH".

[0093] Specific examples of the phenolic compounds having at least one of alkoxyalkyl and hydroxymethyl can be cited as compounds disclosed in WO2010 / 074269.

[0094] The above-mentioned compounds are examples of cross-linking compounds, and are not limited to these. For example, the components other than those mentioned above disclosed on pages 53

[0105] to 55

[0116] of WO2015 / 060357. Furthermore, cross-linking compounds may also be a combination of two or more.

[0095] Among the above-mentioned crosslinking compounds, N,N,N',N'-tetracyclooxypropylmethylenediamine, 1,3-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane, and TAKENATE B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N, 1,3,5-tris(2-hydroxyethyl)isocyanurate, trichloroisocyanurate, N,N,N',N'-tetra(2-hydroxyethyl)hexamethylenediamine, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxymethylphenyl)propane, and 2,2-bis(4-hydroxy-3,5-dimethoxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane are preferred.

[0096] In the liquid crystal alignment agent of the present invention, the content of the crosslinking compound 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. Considering the crosslinking reaction proceeds and exhibits good resistance to AC image retention, it is more preferably 1 to 15 parts by mass.

[0097] The above-mentioned sealing aids include, for example, 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, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropyl Silicon coupling agents including methyl dimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyl dimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-propenyloxypropyltrimethoxysilane, tris(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyl dimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanate propyltriethoxysilane. When using a silane coupling agent, considering its good resistance to AC image retention, it is preferable to use 0.1 to 30 parts by mass relative to 100 parts by mass of polymer content in the liquid crystal alignment agent, and even better to use 0.1 to 20 parts by mass.

[0098] The compounds used to promote amide imidization mentioned above may include: compounds having a basic site (e.g., primary amino group, aliphatic heterocycle (e.g., pyrrolidine skeleton), aromatic heterocycle (e.g., imidazole ring, indole ring), or guanidine group, etc.) (excluding the above-mentioned crosslinking compounds and binding aids.), or compounds that produce the above-mentioned basic site upon calcination are preferred. More preferably, compounds that produce the above-mentioned basic site upon calcination are preferred. For specific examples, compounds represented by the following formulas (B-1) to (B-17) are listed. The content of the compound used to promote amide imidization is preferably 2 mol or less, more preferably 1 mol or less, and even more preferably 0.5 mol or less, relative to 1 mol of amide or amide ester site possessed by polymer (A). [Chemical 31] D represents an organic group that is released upon heating, preferably a terbutoxycarbonyl or 9-pyromethoxycarbonyl.

[0099] The concentration of solid components in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent in the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) can be appropriately selected taking into account viscosity, volatility, etc., and is preferably in the range of 1 to 10% by mass.

[0100] The ideal range of solid component concentration depends on the method used when coating the liquid crystal alignment agent onto the substrate. For example, when using spin coating, a solid component concentration of 1.5 to 4.5% by mass is particularly preferred. When using printing, a solid component concentration of 3 to 9% by mass is preferred, thereby achieving a solution viscosity of 12 to 50 mPa·s. When using inkjet printing, a solid component concentration of 1 to 5% by mass is preferred, thereby achieving a solution viscosity of 3 to 15 mPa·s. The temperature for preparing the polymer composition is preferably 10 to 50°C, more preferably 20 to 30°C.

[0101] <Liquid Crystal Alignment Film, Liquid Crystal Display Element> The liquid crystal alignment film of the present invention is obtained from the above-mentioned liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used in horizontal alignment type or vertical alignment type (VA type) liquid crystal alignment film, wherein it is suitable for liquid crystal alignment film of horizontal alignment type liquid crystal display element such as IPS or FFS type. Furthermore, the liquid crystal alignment film of the present invention is more suitable for use in the photoalignment processing method. In addition, the liquid crystal alignment film of the present invention can be effectively used in various technical applications, such as liquid crystal alignment films other than the above-mentioned applications (liquid crystal alignment films for phase difference films, liquid crystal alignment films for scanning antennas, liquid crystal array antennas, or liquid crystal alignment films for transmission and scattering type liquid crystal dimming elements), or other applications, such as: protective films (e.g., protective films for color filters), spacer films, interlayer insulating films, anti-reflective films, wiring coating films, antistatic films, motor insulating films (gate insulating films for flexible displays), etc. The liquid crystal display element of the present invention includes the above-mentioned liquid crystal alignment film. The liquid crystal display element of the present invention can be manufactured by, for example, a method including the following steps (1) to (3). The liquid crystal display element of the present invention can be manufactured by, for example, 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).

[0102] <Step (1): Step of coating the liquid crystal alignment agent on the substrate> Step (1) is the step of coating the liquid crystal alignment agent of the present invention on the substrate. The specific example of step (1) is as follows. The liquid crystal alignment agent of the present invention is coated on one side of a substrate having a patterned transparent conductive film using a suitable coating method such as roll coating, spin coating, printing, inkjet coating, etc. Here, the substrate is not particularly limited as long as it is a substrate with high transparency, and glass substrates, silicon nitride substrates, acrylic substrates, polycarbonate substrates, etc., can also be used together. In addition, if the reflective liquid crystal display element is only a single-sided substrate, an opaque material such as a silicon wafer can also be used, and the electrode can also be a material that reflects light, such as aluminum. In addition, when manufacturing IPS or FFS type liquid crystal display elements, a substrate having electrodes made of a patterned comb-shaped transparent conductive film or metal film and a counter substrate without electrodes are used.

[0103] Methods for coating a liquid crystal alignment agent onto a substrate and forming a film include screen printing, offset printing, flexographic printing, inkjet printing, and spraying. Among these, inkjet printing is preferred for coating and forming a film.

[0104] <Step (2): Calcination of the coated liquid crystal alignment agent> Step (2) is the step of calcining the liquid crystal alignment agent coated on the substrate to form a film. Specific examples of step (2) are as follows. After coating the liquid crystal alignment agent onto the substrate in step (1), the solvent can be evaporated or the polyamide or polyamide ester can be thermally imidized by heating means such as a hot plate, a thermally circulating oven, or an IR (infrared) oven. The drying and calcination steps after coating the liquid crystal alignment agent of the present invention can be performed at any temperature and time, and can be repeated multiple times. The calcination temperature can be, for example, 40~180°C. Considering the need to shorten the processing time, it can also be performed at 40~150°C. The calcination time is not particularly limited at this time, for example, 1~10 minutes or 1~5 minutes. When performing thermal amide formation of polyamide or polyamide ester, a calcination step can be added after the above-mentioned organic solvent removal step, for example, at a temperature range of 150~300°C or 150~250°C. The calcination time is not particularly limited, but can be 5~40 minutes or 5~30 minutes. If the film after calcination is too thin, the reliability of the liquid crystal display element may decrease; therefore, 5~300 nm is ideal, and 10~200 nm is even more ideal.

[0105] <Step (3): Alignment Processing Step> Step (3) is a step of aligning the calcined film (coating) obtained in step (2) as appropriate. That is, in horizontal alignment type liquid crystal display elements such as IPS or FFS, alignment capability imparting processing is applied to the coating. On the other hand, in vertical alignment type liquid crystal display elements such as VA or PSA, the formed coating can be used directly as a liquid crystal alignment film, but alignment capability imparting processing can also be applied to the coating. Alignment processing methods for liquid crystal alignment films include rubbing processing and photoalignment processing, with photoalignment processing being more ideal. Photoalignment processing methods include irradiating the surface of the above-mentioned film with radiation deflected in a certain direction, and, as appropriate, heating the film at a temperature of 150~250°C to impart liquid crystal alignment properties (also known as liquid crystal alignment capability). The radiation can be ultraviolet light or visible light with a wavelength of 100~800nm. The preferred ultraviolet light is ultraviolet light with a wavelength of 100~400nm, and more preferably ultraviolet light with a wavelength of 200~400nm.

[0106] The radiation dose is ideally 1~10,000 mJ / cm2, more preferably 100~5,000 mJ / cm2, even more preferably 100~1,500 mJ / cm2, particularly preferably 100~1,000 mJ / cm2, and even more preferably 100~400 mJ / cm2. When using conventional liquid crystal alignment agents, the light irradiation dose for alignment treatment is 100~5,000 mJ / cm2. However, the liquid crystal alignment agent of the present invention can obtain a liquid crystal alignment film with suppressed variation (non-uniformity) of liquid crystal alignment properties within the liquid crystal alignment film surface, even if the light irradiation dose for alignment treatment is reduced.

[0107] Furthermore, when irradiated with radiation, in order to improve the alignment of the liquid crystal, the substrate having the film can be heated at 50 to 250°C while being irradiated. The liquid crystal alignment film prepared in this manner can stably align the liquid crystal molecules in a certain direction. Also, the liquid crystal alignment film irradiated with polarized radiation using the above method can be subjected to contact treatment with water or solvent, or the irradiated liquid crystal alignment film can be subjected to heat treatment.

[0108] The solvent used in the above-mentioned contact treatment is not particularly limited as long as it can dissolve the decomposition products generated from the film due to radiation irradiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl ceroxysulfate, 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. The solvent may be one type or a combination of two or more types.

[0109] <Step (4): Step of performing heat treatment> Step (4) is a step of performing heat treatment on the liquid crystal alignment film that has undergone alignment treatment in step (3). The heat treatment can also be performed on the irradiated film (coating) that has been irradiated by radiation. The ideal temperature for heat treatment of the irradiated coating is 50~300℃, and 120~250℃ is more ideal. The heat treatment time is preferably 1~30 minutes.

[0110] <Step (5): Steps for fabricating liquid crystal cells> Prepare two substrates with liquid crystal alignment films formed as described above, and place liquid crystal between the two substrates facing each other. Specifically, the following two methods can be listed. The first method is to first arrange the two substrates facing each other with their respective liquid crystal alignment film faces facing each other, with a gap (cell gap) between them. Then, the peripheral portions of the two substrates are bonded together with a sealant, and the liquid crystal composition is injected into the cell gap separated by the substrate surface and the sealant until it contacts the film surface, and then the injection hole is sealed.

[0111] Furthermore, the second method is called the ODF (One Drop Fill) method. On one of the two substrates on which the liquid crystal alignment film has been formed, a UV-curable sealant is applied to a predetermined location. Then, liquid crystal composition is dropped onto a predetermined number of locations on the surface of the liquid crystal alignment film. Next, the other substrate is bonded with the liquid crystal alignment film facing each other, pushing the liquid crystal composition across the entire substrate and bringing it into contact with the film surface. Then, the entire substrate is irradiated with UV light to harden the sealant. In either method, it is more ideal to heat the liquid crystal composition until it reaches a temperature of isotropic phase, and then slowly cool it to room temperature to remove flow alignment issues during liquid crystal filling. Furthermore, when rubbing the coating, the two substrates are arranged facing each other at a predetermined angle, for example, orthogonal or antiparallel, with the rubbing direction of each coating. The sealant can be, for example, epoxy resin containing a hardener and alumina balls as spacers. There are no particular limitations on the liquid crystal composition described above. Various liquid crystal compositions containing at least one liquid crystal compound (liquid crystal molecule) and exhibiting positive or negative dielectric anisotropy can be used. Furthermore, liquid crystal compositions with positive dielectric anisotropy are also referred to as positive liquid crystals, and liquid crystal compositions with negative dielectric anisotropy are also referred to as negative liquid crystals. Examples of liquid crystal compositions include nematic liquid crystal compositions, smectic liquid crystal compositions, and cholesterol liquid crystal compositions, with nematic liquid crystal compositions being preferred. The liquid crystal compositions described above may also contain liquid crystal compounds having fluorine atoms, hydroxyl groups, amino groups, fluorine-containing groups (e.g., trifluoromethyl), cyano groups, alkyl groups, alkoxy groups, alkenyl groups, isothiocyanate groups, heterocyclic rings, cycloalkanes, cycloalkenes, steroid skeletons, benzene rings, or naphthyl rings. They may also contain compounds with two or more rigid sites exhibiting liquid crystal properties (mesogen skeletons) within the molecule (e.g., rigid biphenyl structures, or biphenyl structures linked by alkyl groups forming a double mesogenous liquid crystal compound). In the aforementioned liquid crystal compositions, additives may be added to improve the alignment of the liquid crystal. Examples of such additives include photopolymerizable monomers such as compounds with polymerizable groups; optically active compounds (e.g., Merck S-811); antioxidants; ultraviolet absorbers; pigments; defoamers; polymerization initiators; or polymerization inhibitors. Positive liquid crystals include, for example, Merck's ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, or MLC-7081. Negative liquid crystals include, for example, Merck's MLC-6608, MLC-6609, MLC-6610, or MLC-7026-100. Furthermore, liquid crystals containing compounds with polymerizable groups include, for example, Merck's MLC-3023.

[0112] 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 of a polarizing film called "H film" by extending polyvinyl alcohol to absorb iodine through a cellulose acetate protective film clamping edge, or a polarizing plate composed of the H film itself.

[0113] An IPS substrate using a comb-tooth electrode substrate in an IPS mode has: a substrate; a plurality of linear electrodes formed on the substrate and arranged in a comb-tooth shape; and a liquid crystal alignment film formed on the substrate in such a way as to cover the linear electrodes. Furthermore, an FFS substrate using a comb-tooth electrode substrate in an FFS 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 arranged in a comb-tooth shape; and a liquid crystal alignment film formed on the insulating film in such a way as to cover the linear electrodes.

[0114] FIG1 is a schematic cross-sectional view showing an example of a horizontal electric field liquid crystal display element of the present invention, which is an example of an IPS mode liquid crystal display element. In the horizontal electric field liquid crystal display element 1 illustrated in FIG1, liquid crystal 3 is sandwiched between a comb electrode substrate 2 having a liquid crystal alignment film 2c and a counter substrate 4 having a liquid crystal alignment film 4a. The comb electrode substrate 2 has: a substrate 2a; a plurality of linear electrodes 2b formed on the substrate 2a and arranged in a comb shape; and a liquid crystal alignment film 2c formed on the substrate 2a in such a way as to cover the linear electrodes 2b. The counter substrate 4 has a substrate 4b and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2c is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4c is also the liquid crystal alignment film of the present invention. In this horizontal electric field liquid crystal display element 1, if a voltage is applied to the linear electrodes 2b, an electric field will be generated between the linear electrodes 2b as shown by the electric field line L.

[0115] FIG2 is a schematic cross-sectional view showing another example of the horizontal electric field liquid crystal display element of the present invention, which is an example of an FFS mode liquid crystal display element. In the horizontal electric field liquid crystal display element 1 illustrated in FIG2, liquid crystal 3 is sandwiched between a comb electrode substrate 2 having a liquid crystal alignment film 2h and a counter substrate 4 having a liquid crystal alignment film 4a. The comb electrode substrate 2 has: a substrate 2d; a surface electrode 2e formed on the substrate 2d; an insulating film 2f formed on the surface electrode 2e; and a plurality of linear electrodes 2g formed on the insulating film 2f and arranged in a comb shape; and a liquid crystal alignment film 2h formed on the insulating film 2f in such a way as to cover the linear electrodes 2g. The counter substrate 4 has: a substrate 4b and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2h is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4a is also the liquid crystal alignment film of the present invention. In this horizontal electric field liquid crystal display element 1, if a voltage is applied to the surface electrode 2e and the linear electrode 2g, an electric field will be generated between the surface electrode 2e and the linear electrode 2g, as shown by the electric field line L. [Example]

[0116] The following examples illustrate the invention in more detail, but the invention is not limited thereto. The abbreviations of the compounds used and the methods for determining their properties are as follows. Also, "Boc" represents the third butoxycarbonyl group.

[0117] (Specific diamine) WA-1~WA-2: Each is a compound represented by the formula (WA-1)~(WA-2) [Chemistry 32]

[0118] (Other diamines) A1~A8: Each is a compound represented by the following formulas (A1)~(A8) [Chemical 33] The compounds represented by formulas A4 and A5 are synthesized according to the synthesis method described in WO2020 / 080477.

[0119] (Tetracarboxylic acid dianhydride) B1~B2: Each is a compound represented by the formulas (B1)~(B2) [Chemistry 34]

[0120] (Additives) AD-1~AD-2: Each is a compound represented by the formula (AD-1)~(AD-2) [Chemistry 35]

[0121] (Solvent) NMP: N-methyl-2-pyrrolidone; BCS: ethylene glycol monobutyl ether; DMF: dimethylformamide; DMAc: dimethylacetamide; THF: tetrahydrofuran

[0122] (Viscosity Measurement) The viscosity of the solution was measured using a TVE-22H type E viscometer (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL, using a conical rotor TE-1 (1°34', R24), at a temperature of 25°C.

[0123] (Determination of molecular weight) The molecular weight of polyamide was determined using a room temperature gel permeation chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko Corporation) and a column (KD-803 and KD-805 in series) (manufactured by Showa Denko Corporation) in the following manner. Column temperature: 50℃ Solution: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, anhydrous phosphoric acid crystals (orthophosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L) Flow rate: 1.0 mL / min Standard samples used for the test line: TSK standard polyethylene oxide (molecular weight; approx. 900,000, 150,000, 100,000 and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight; approx. 12,000, 4,000 and 1,000) (manufactured by Polymer Laboratory Corporation).

[0124] <Synthesis of Specific Diamines (WA-1)~(WA-2)> The synthesis of specific diamines (WA-1)~(WA-2) is detailed below. Furthermore, diamine (WA-2) is a novel compound not disclosed in the literature.

[0125] (1H-NMR determination) Apparatus: Fourier transform superconducting nuclear magnetic resonance spectrometer (FT-NMR) "AVANCE III" (BRUKER) 500MHz. Solvent: Deuterated dimethyl monoxide (DMSO-d6, standard substance: tetramethylsilane).

[0126] (Single Synthesis Example 1: Synthesis of (WA-1)) The diamine (WA-1) was synthesized according to the following route. [Chemical 36] 6-bromo-2-naphthol (31.1 g, 140 mmol), potassium carbonate (38.7 g, 280 mmol), and potassium iodide (1.16 g, 7 mmol) were dissolved in DMF (249 g) in a 1 L 4-necked flask, heated to 100 °C and stirred. A solution of 1,4-dichlorobutane (8.8 g, 70 mmol) dissolved in DMF (63 g) was slowly added, and the mixture was stirred for 15 hours. After confirming the completion of the reaction by HPLC, the mixture was cooled to room temperature, and pure water (620 g) was added and stirred for 1 hour. The precipitated crystals were filtered off, and the obtained solid was washed with methanol and dried under reduced pressure to obtain WA-1-1 (yield 28.7 g, 57.4 mmol, yield 82%, white solid). 1H-NMR (500MHz, DMSO-d6); δ (ppm) = 8.10 (2H, s), 7.83-7.75 (4H, m), 7.56-7 .54(2H,m)、7.38(2H,s)、7.23-7.22(2H,m)、4.19(4H,t)、1.99-1.95(4H,m)

[0127] In a 1L 4-necked flask, add WA-1-1 (20.0 g, 40 mmol), diphenyl ketone imine (15.9 g, 88 mmol), triphenylacetone dipalladium (Pd2(dba)3) (0.7 g, 0.8 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl (XPhos) (1.52 g, 3.2 mmol), sodium tributoxide (10.8 g, 112 mmol), and THF (400 g). Heat to 70°C and stir for 1 hour. Concentrate the reaction solution to 200 g, add pure water (200 g), and stir for 1 hour. Collect the precipitated crystals by vacuum filtration, transfer to a 4-necked flask, dissolve in DMAc (256 g), slowly add trifluoroacetic acid (12.5 g, 110 mmol), and heat to 50°C. After stirring for 30 minutes, the solution was brought back to room temperature, and N,N,N',N'-tetramethylethylenediamine (TMEDA) (16.9 g, 146 mmol) was added for neutralization. The reaction solution was concentrated to 128 g, and methanol (256 g) was added, followed by stirring for 1 hour. The precipitated crystals were filtered off, and the obtained solid was washed with methanol and dried under reduced pressure to obtain WA-1 (yield 13.0 g, 34.9 mmol, 88% yield, light brown solid). The 1H-NMR results shown below confirmed that this solid was a diamine (WA-1). 1H-NMR (500MHz, DMSO-d6); δ (ppm) = 7.49-7.47(2H,m), 7.44-7.42(2H,m), 7.10(2H,d), 6.99-6 .97(2H,m)、6.90-6.88(2H,m)、6.79(2H,d)、5.08-5.06(4H,m)、4.08(4H,t)、1.96-1.92(4H,m)

[0128] (Monomer Synthesis Example 2: Synthesis of (WA-2)) The diamine (WA-2) was synthesized according to the following pathway. [Chem. 37]

[0129] In a 300 mL four-necked flask, 1,4-dichlorobutane (63.5 g, 500 mmol) was dissolved in DMF (86 g), and potassium carbonate (13.8 g, 100 mmol) was added. The mixture was heated to 100 °C and stirred. A solution of 4-bromo-4'-hydroxybiphenyl (12.4 g, 50 mmol) dissolved in DMF (38 g) was added, and the mixture was stirred for 2 hours. After confirming the reaction was complete by HPLC, the mixture was cooled to room temperature, and the precipitated salt was removed. The solution was concentrated to 64 g, and methanol (180 g) and pure water (180 g) were added. The mixture was stirred for 1 hour. The precipitated crystals were filtered off, and the obtained solid was washed with methanol and dried under reduced pressure to obtain WA-2-1 (yield 14.6 g, 43.0 mmol, 86% yield, white solid). 1H-NMR (500MHz, DMSO-d6); δ(ppm)=7.61-7.58(6H,m), 7.02(2H,d), 4.05(2H,t), 3.72(2H,t), 1.88-1.87(4H,m)

[0130] Add WA-2-1 (13.6 g, 40 mmol), 6-bromo-2-naphthol (8.9 g, 40 mmol), potassium carbonate (13.8 g, 100 mmol), and DMF (135 g) to a 500 mL four-necked flask, heat to 100 °C, and stir for 18 hours. After confirming the completion of the reaction by HPLC, return the solution to room temperature, add pure water (202 g), and stir for 1 hour. Filter the precipitated crystals, wash the obtained solid with acetonitrile, and dry under reduced pressure to obtain WA-2-2 (yield 19.5 g, 37.1 mmol, yield 93%, white solid). 1H-NMR (500MHz, DMSO-d6); δ (ppm) = 8.11 (1H,m), 7.83-7.75 (2H,m), 7.61-7.55 (7H,m ), 7.37(1H,m), 7.23(1H,m), 7.04-7.03(2H,m), 4.17-4.11(4H,m), 1.04-1.03(4H,m)

[0131] Add WA-2-2 (19.4 g, 37 mmol), diphenyl ketone imine (14.7 g, 81 mmol), triphenylacetone dipalladium (Pd2(dba)3) (0.6 g, 0.7 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl (XPhos) (1.41 g, 2.9 mmol), sodium tributoxide (9.9 g, 103 mmol), and THF (389 g) to a 1 L 4-necked flask. Heat to 70 °C and stir for 1 hour. Concentrate the reaction solution to 190 g, add pure water (200 g), and stir for 1 hour. Collect the precipitated crystals by vacuum filtration, transfer to a 4-necked flask, dissolve in THF (537 g), slowly add trifluoroacetic acid (12.6 g, 111 mmol), and heat to 50 °C. After stirring for 30 minutes, the solution was brought back to room temperature, and N,N,N',N'-tetramethylethylenediamine (TMEDA) (17.2 g, 148 mmol) was added and neutralized. The reaction solution was concentrated to 260 g, and methanol (260 g) was added, followed by stirring for 1 hour. The precipitated crystals were filtered off, and the obtained solid was washed with methanol and dried under reduced pressure to obtain WA-2 (yield 13.3 g, 33.4 mmol, 90% yield, light brown solid). The 1H-NMR results shown below confirmed that this solid was a diamine (WA-2). 1H-NMR (500MHz, DMSO-d6); δ (ppm) = 7.49-7.42 (4H, m), 7.28-7.27 (2H, m), 7.09 (1H, d), 6.99-6.88 (4H,m), 6.79(1H,d), 6.622-6.60(2H,m), 5.11-5.10(4H,m), 4.07-4.05(4H,m), 1.98-1.90(4H,m)

[0132] <Synthesis of Polymers> (Synthesis Example 1) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), WA-1 (2.23 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.39 g, 28.5 mmol), and NMP (104 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyacrylic acid (A-1) solution with a solid content concentration of 12% by mass (viscosity: 379 mPa·s). The number average molecular weight (Mn) of this polyacrylic acid was 13,242, and the weight average molecular weight (Mw) was 34,231.

[0133] (Synthesis Example 2) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), WA-2 (2.39 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.42 g, 28.7 mmol), and NMP (105 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyacrylic acid (A-2) solution with a solid content concentration of 12% by mass (viscosity: 398 mPa·s). The Mn of this polyacrylic acid was 12,019, and the Mw was 33,291.

[0134] (Synthesis Example 3) A1 (0.649 g, 6.00 mmol), A8 (4.78 g, 24.0 mmol), B2 (5.59 g, 28.5 mmol), and NMP (99.2 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature for 5 hours to obtain a polyacrylic acid (B-1) solution with a solid content of 10% by mass (viscosity: 338 mPa·s). The Mn of this polyacrylic acid was 15,932, and the Mw was 39,013.

[0135] (Synthesis Example 4 (Comparative)) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), A3 (1.92 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.42 g, 28.7 mmol), and NMP (101 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyacrylic acid (RA-1) solution with a solid content of 12% by mass (viscosity: 382 mPa·s). The Mn of this polyacrylic acid was 11,912, and the Mw was 33,413.

[0136] (Synthesis Example 5 (Comparative)) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.07 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.38 g, 28.4 mmol), and NMP (102 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyacrylic acid (RA-2) solution with a solid content of 12% by mass (viscosity: 411 mPa·s). The Mn of this polyacrylic acid was 12,018, and the Mw was 37,021.

[0137] (Synthesis Example 6 (Comparative)) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), A5 (2.22 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.38 g, 28.4 mmol), and NMP (103 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyacrylic acid (RA-3) solution with a solid content concentration of 12% by mass (viscosity: 404 mPa·s). The Mn of this polyacrylic acid was 10,383, and the Mw was 36,113.

[0138] (Synthesis Example 7 (Comparative)) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), A6 (2.15 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.46 g, 28.8 mmol), and NMP (103 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyacrylic acid (RA-4) solution with a solid content of 12% by mass (viscosity: 401 mPa·s). The Mn of this polyacrylic acid was 10,099, and the Mw was 36,030.

[0139] The types and amounts of diamine and tetracarboxylic acid components used in Synthetic Examples 1-7 are summarized in Table 1. In the table, the values ​​in parentheses represent the amount of monomer used relative to a total of 100 moles of each component (moles).

[0140] [Table 1] Synthesis example polyamide Tetracarboxylic acid components diamine component Specific diamine Other diamines 1 A-1 B1(100) WA-1(20) A1(30)A2(30)A7(20) 2 A-2 B1(100) WA-2(20) A1(30)A2(30)A7(20) 3 B-1 B2(100) - A1(20)A8(80) 4 RA-1 B1(100) - A1(30)A2(30)A3(20)A7(20) 5 RA-2 B1(100) - A1(30)A2(30)A4(20)A7(20) 6 RA-3 B1(100) - A1(30)A2(30)A5(20)A7(20) 7 RA-4 B1(100) - A1(30)A2(30)A6(20)A7(20)

[0141] <Preparation of liquid crystal alignment agent> (Example 1) NMP (9.33g) and BCS (4.00g) were added to the polyacrylic acid (A-1) solution (6.67g) obtained in Synthesis Example 1, and stirred at room temperature for 2 hours to obtain liquid crystal alignment agent (V-1).

[0142] (Example 2) To the polyacrylic acid (A-1) solution (5.30 g) obtained in Synthesis Example 1, add the polyacrylic acid (B-1) solution (9.54 g), NMP (3.78 g), BCS (9.00 g), a 10% mass dilution of NMP in AD-1 (0.800 g), and a 1% mass dilution of NMP in AD-2 (1.59 g), and stir at room temperature for 2 hours to obtain liquid crystal alignment agent (V-2).

[0143] (Example 3) The polyacrylic acid solution used was changed from solution (A-1) to solution (A-2), and the same procedure as in Example 2 was followed to obtain liquid crystal alignment agent (V-3).

[0144] (Comparative Example 1) to (Comparative Example 4) The polyacrylic acid solution used was changed from solution (A-1) to solution (RA-1) to (RA-4), and the same procedure as in Example 1 was followed to obtain liquid crystal alignment agents (RV-1) to (RV-4).

[0145] (Comparative Example 5)~(Comparative Example 6) The polyacrylic acid solution used was changed from solution (A-1) to solution (RA-2)~(RA-3), and the same procedure as in Example 2 was followed to obtain liquid crystal alignment agents (RV-5)~(RV-6).

[0146] The specifications of the liquid crystal alignment agents obtained in Examples 1-3 and Comparative Examples 1-6 above are shown in Table 2. The values ​​in parentheses of the polymer components represent the proportion (parts by mass) of each polymer component relative to the total 100 parts by mass of the polymer components.

[0147] [Table 2] Liquid crystal alignment agent polymer components Additive ingredients 1st ingredient 2nd ingredient Example 1 V-1 A-1(100) - - Example 2 V-2 A-1(40) B-1(60) AD-1, AD-2 Example 3 V-3 A-2(40) B-1(60) AD-1, AD-2 Comparative Example 1 RV-1 RA-1(100) - - Comparative Example 2 RV-2 RA-2(100) - - Comparative Example 3 RV-3 RA-3(100) - - Comparative Example 4 RV-4 RA-4(100) - - Comparative Example 5 RV-5 RA-2(40) B-1(60) AD-1, AD-2 Comparative Example 6 RV-6 RA-3(40) B-1(60) AD-1, AD-2

[0148] Using the liquid crystal alignment agent obtained above, an FFS-driven liquid crystal cell was fabricated according to the procedure shown below, and various evaluations were performed.

[0149] <Structure of FFS-Driven Liquid Crystal Cell> A liquid crystal cell with an FFS mode liquid crystal display element is fabricated. First, a substrate with electrodes is prepared. The substrate is a rectangular glass substrate of 30mm × 50mm and 0.7mm thick. An ITO electrode with a solid pattern, constituting the first opposing electrode, is formed on the substrate. A SiN (silicon nitride) film, formed by CVD (chemical vapor deposition), is formed on the first opposing electrode as the second layer. The SiN film of the second layer has a thickness of 500nm and serves as an interlayer insulating film. On the second SiN film, a comb-shaped pixel electrode, formed by patterning the ITO film, is disposed as the third layer, forming two pixels, the first pixel and the second pixel. The dimensions of each pixel are 10mm in length and 5mm in width. At this time, the first layer's opposing electrode and the third layer's pixel electrode are electrically insulated by the SiN film of the second layer. The third layer's pixel electrode has a comb-like shape with multiple 3μm wide electrode elements arranged in parallel at 6μm intervals, each element having an inner angle of 160°. Each pixel has a first region and a second region, with the lines connecting the multiple electrode elements serving as the boundary. Then, the liquid crystal alignment agents (V-1) to (V-3) and (RV-1) to (RV-6) obtained in Examples 1 to 3 and Comparative Examples 1 to 6 are filtered through a 1.0μm pore size filter and then spin-coated onto the prepared electrode substrate (first glass substrate) and a glass substrate (second glass substrate) with a 4μm high columnar spacer on the back side where an ITO film has been formed. After drying on a hot plate at 80°C for 2 minutes, the film is calcined in a hot air circulating oven at 230°C for 30 minutes to form a coating with a thickness of 100 nm. This coating surface is then irradiated with linearly polarized ultraviolet light of 254 nm wavelength with an extinction ratio of 26:1 through a polarizing plate according to the irradiation amounts shown in Table 3 to perform alignment treatment, thereby obtaining a substrate with a liquid crystal alignment film. Furthermore, the liquid crystal alignment film formed on the aforementioned electrode substrate undergoes alignment treatment so that the direction of equal division of the inner angles of the pixel bends is perpendicular to the alignment direction of the liquid crystal. The liquid crystal alignment film formed on the second glass substrate undergoes alignment treatment so 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 fabricating the liquid crystal cells. Using the two substrates as a set, a sealant (Mitsui Chemicals XN-1500T) is printed on the substrate, and another substrate is bonded together so that the alignment directions of the liquid crystal alignment film surfaces facing each other are 0°. The sealant was then hardened by heating at 150°C for 60 minutes, creating a hollow cell. Liquid crystal MLC-3019 (manufactured by Merck) was injected into this hollow cell using a reduced-pressure injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour, left to stand overnight, and then used for evaluation.

[0150] <Evaluation of In-Plane Uniformity of Contrast Ratio> The variation in the torsion angle of liquid crystal cells was evaluated using AxoStep manufactured by AXOMETRICS. The liquid crystal cells fabricated above were placed on a measurement stage, and the distribution of the circular phase difference within the pixel plane was measured without applied voltage. Three times the standard deviation σ was calculated, i.e., 3σ. For in-plane uniformity, a smaller value of 3σ is considered better. Based on the evaluation criteria, a value less than 1.00 was rated as "Excellent," 1.00 or higher but less than 1.10 was rated as "Good," and a value greater than 1.10 was rated as "Poor." The results of the evaluation of liquid crystal display elements using the liquid crystal alignment agents of the above examples and comparative examples are shown in Table 3.

[0151] <Evaluation of the Stability of Liquid Crystal Alignment> This evaluation assesses the image retention (also known as AC image retention) caused by the deterioration of the alignment performance of the liquid crystal alignment film under long-term AC driving. For the FFS-driven liquid crystal cell fabricated above, an AC voltage of 60Hz ±4V was applied for 120 hours at a constant temperature of 60°C. Afterwards, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited, and the cell was left at room temperature for one day. For the liquid crystal cell that underwent the above treatment, the deviation between the alignment direction of the liquid crystal in region 1 and region 2 of the pixel under the unapplied voltage condition was calculated by angle. Specifically, the liquid crystal cell was placed between two polarizing plates arranged with their polarization axes orthogonal. The backlight was turned on, and the arrangement angle of the liquid crystal cell was adjusted to minimize the transmitted light intensity in region 1 of the pixel. Then, the rotation angle required to rotate the liquid crystal cell in a manner that minimizes the transmitted light intensity in region 2 of the pixel was determined. The stability of liquid crystal alignment is considered better the smaller the value of this rotation angle. In terms of evaluation criteria, less than 0.05 degrees is rated as "excellent", more than 0.05 degrees and less than 0.10 degrees is rated as "good", and more than 0.10 degrees is rated as "poor".

[0152] The evaluation results of liquid crystal display elements implemented using the liquid crystal alignment agents of the above embodiments and comparative examples are shown in Table 3.

[0153] [Table 3]

[0154] As shown in Table 3, the liquid crystal alignment film obtained by using a liquid crystal alignment agent containing specific diamines WA-1 to WA-2 exhibits higher in-plane uniformity with less light irradiation compared to a liquid crystal alignment film obtained by using a liquid crystal alignment agent containing a diamine component that does not contain the specific diamine. Furthermore, it demonstrates liquid crystal alignment stability equal to or higher than that of conventional liquid crystal alignment films.

[0155] The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can be applied to liquid crystal display elements. Furthermore, these elements are useful in liquid crystal displays for display purposes, and also in dimming windows, shutters, etc., for controlling light transmission and blocking. [Industrial Applicability]

[0156] By using the liquid crystal alignment agent of the present invention, the variation (non-uniformity) of the torsion angle of the liquid crystal within the liquid crystal alignment film is small, and the range of light irradiation for obtaining the liquid crystal alignment film is expanded, enabling the efficient acquisition of high-quality liquid crystal alignment films. Therefore, its application in liquid crystal display elements requiring high display quality is expected. Furthermore, these elements are also useful in liquid crystal displays for display purposes, and further in dimming windows, shutters, etc., for controlling light transmission and blocking. [Simplified Explanation of the Diagram]

[0013] FIG1 shows a schematic cross-sectional view of one example of the horizontal electric field liquid crystal display element of the present invention. FIG2 shows a schematic cross-sectional view of another example of the horizontal electric field liquid crystal display element of the present invention.

Claims

1. A liquid crystal alignment agent, characterized in that it contains a polymer (A), which is selected from at least one of the group consisting of a polyimide precursor having a repeating unit (a1) represented by the following formula (1) and a polyimide that is an imide derivative of the polyimide precursor, wherein in formula (1), X1 represents a tetravalent organic group, Y1 is a divalent organic group represented by any one of the following formulas (h-1), (h-2), and (h-4), R and Z each independently represent a hydrogen atom or a monovalent organic group, wherein in formulas (h-1), (h-2), and (h-4), Ra1, Ra2, and Ra4 represent monovalent organic groups, L represents a base represented by the following formula (H1), m is each independently an integer from 0 to 6, n is each independently an integer from 0 to 4, when multiple Ra1, Ra2, and Ra4 are present, they may be the same or different, and * represents an atomic bond. In formula (H1), L1 and L1' each independently represent a single bond, -O-, -S-, -C(=O)-, -OC(=O)-, or -C(=O)-NR-; R represents a hydrogen atom or a monovalent organic group, A represents an alkyl group with 4 to 10 carbon atoms, and * represents an atomic bond.

2. The liquid crystal alignment agent as claimed in claim 1, wherein, The formula (H1) is based on the following bases: "*-(CH2)n-*", "*-O-(CH2)nO-*", "*-C(=O)-(CH2)nC(=O)-*", "*-C(=O)-NR-(CH2)nO-*", "*-OC(=O)-(CH2)nO-*", "*-OC(=O)-(CH2)nOC(=O)-*", "*-OC(=O)-(CH2)nC(=O)-O-*", and "*-S". The radicals represented by "-(CH2)nS-*", "*-C(=O)-NR-(CH2)n-NR-C(=O)-*", "*-C(=O)-O-(CH2)nOC(=O)-*", "*-O-(CH2)n-*", "*-S-(CH2)n-*", or "*-NR-C(=O)-(CH2)nC(=O)-NR-*", where R represents a hydrogen atom or a monovalent organic radical, n is an integer from 4 to 10, and * represents an atomic bond.

3. The liquid crystal alignment agent as claimed in claim 1, wherein, The polymer (A) is selected from at least one polymer in the group consisting of polyimide precursors having repeating units (a2) represented by the following formula (2) and polyimides of polyimides which are polyimides of the polyimide precursors. In formula (2), X2 represents a tetravalent organic group, Y2 represents a divalent organic group represented by the following formulas (o-1) to (o-14), and R and Z are synonyms with R and Z in the above formula (1). In formulas (o-1) to (o-14), * represents an atomic bond. In formulas (o-13) to (o-14), the two m are independent. Any hydrogen atom on the ring of benzene, biphenyl structure or naphthalene ring in formulas (o-1) to (o-14) can also be replaced by a monovalent group.

4. The liquid crystal alignment agent as claimed in claim 1, wherein, The polymer (A) is a polymer selected from at least one of the following groups: a polyimide precursor composed of at least one repeating unit (a2') and a repeating unit (a3) ​​composed of the following formula (2') and the following formula (3); and a polyimide composed of the polyimide of the polyimide precursor. In formulas (2') and (3), X2' and X3 represent tetravalent organic groups, Y2' represents a divalent organic group represented by the following formula (O2), Y3 represents a divalent organic group with 6 to 30 carbon atoms having the group "-N(D)- (D represents a carbamate protecting group)", and R and Z are synonyms with R and Z in formula (1) above. In formula (O2), m represents an integer from 0 to 2. When m is 0, Ar2' represents a benzene ring or a naphthalene ring. When m is 1 to 2, each Ar2' independently represents a benzene ring. Any hydrogen atom on the ring of Ar2' can also be replaced by a monovalent group. Q2' represents a single bond or -O-. * represents an atomic bond. When there are multiple Ar2' and Q2', they can be the same or different.

5. The liquid crystal alignment agent as claimed in claim 1, wherein, X1 is a tetravalent organic group derived from acyclic aliphatic tetracarboxylic dianhydride or its derivatives, alicyclic tetracarboxylic dianhydride or its derivatives, or aromatic tetracarboxylic dianhydride or its derivatives, and is a tetravalent organic group derived from tetracarboxylic dianhydride or its derivatives having at least one substructure selected from the group consisting of cyclobutane ring structure, cyclopentane ring structure and cyclohexane ring structure.

6. The liquid crystal alignment agent as claimed in claim 1, wherein, In the polymer (A), the total content of the repeating unit (a1) and the amide structure of the repeating unit (a1) is 5 to 100 mol of all repeating units.

7. The liquid crystal alignment agent as claimed in claim 1, wherein, In the polymer (A), the total content of the repeating unit (a1) and the amide structure of the repeating unit (a1) is more than 5 mol% and less than 95 mol% of all repeating units.

8. The liquid crystal alignment agent as claimed in claim 3, wherein, In the polymer (A), the total content of the repeating unit (a1), the repeating unit (a2), and their aceiminated structures is more than 10 mol% of all repeating units.

9. The liquid crystal alignment agent as claimed in claim 1 is used in the formation of a liquid crystal alignment film for photoalignment processing.

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

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

12. A method for manufacturing a liquid crystal display element, comprising the following steps (1) to (3): Step (1): applying a liquid crystal alignment agent as claimed in any one of claims 1 to 9 onto a substrate; Step (2): calcining the applied liquid crystal alignment agent; Step (3): performing alignment treatment on the calcined film obtained in step (2).

13. A method for manufacturing a liquid crystal display element as described in claim 12, wherein, This alignment process is a photoalignment process.

14. A method for manufacturing a liquid crystal display element as described in claim 13, wherein, The radiation dose during this photoalignment process is 100~1,500 mJ / cm2.

15. The method for manufacturing a liquid crystal display element as claimed in claim 12 further includes the following step (4): Step (4): The calcined film that has undergone alignment treatment in step (3) is subjected to a heat treatment of 50 to 300°C.

16. A liquid crystal display element obtained by a method of manufacturing a liquid crystal display element as claimed in any one of claims 12 to 15.

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