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

Abstract

This invention provides a liquid crystal alignment agent that exhibits minimal variation (non-uniformity) in the torsion angle of liquid crystal within the liquid crystal alignment film surface and can still form a liquid crystal alignment film with high layer separation even when using two or more polymers, and a liquid crystal display element having the liquid crystal alignment film. A liquid crystal alignment agent is characterized by containing a polymer (P), which is selected from at least one group consisting of a polyimide precursor obtained using a diamine component containing a diamine (O) represented by the following formula (DA) and polyimides that are amides of the polyimide precursor. The definitions of each designation are as described in the specification.

Description

[Technical Field]

[0001] This invention relates to a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, a liquid crystal display element having the liquid crystal alignment film, and novel diamines and polymers suitable for them. [Previous Technology]

[0002] Liquid crystal display (LCD) elements are widely used in applications ranging from small devices such as mobile phones and smartphones to larger applications such as televisions and monitors. Furthermore, various driving methods have been developed, including different electrode structures and the physical properties of the liquid crystal molecules used. Examples of known LCD elements using various modes include TN (Twisted Nematic), STN (Super Twisted Nematic), VA (Vertical Alignment), IPS (In-Plane Switching), and FFS (Fringe Field Switching). These LCD elements generally possess a liquid crystal alignment film, essential for controlling the alignment of liquid crystal molecules. Regarding the material of the liquid crystal alignment film, considering good heat resistance, mechanical strength, and affinity for liquid crystals, polyamide and polyimide are generally used.

[0003] Currently, the most widely used liquid crystal alignment film in industry is manufactured through a so-called friction treatment, which involves rubbing the surface of a resin film such as polyimide formed on an electrode substrate in one direction with a cloth such as cotton, nylon, or polyester. Friction alignment treatment is a simple and highly productive method. As an alternative to friction alignment treatment, photoalignment treatment, which imparts alignment capability to liquid crystals by irradiating them with polarized radiation, is known. Regarding photoalignment treatment, methods utilizing photoisomerization reactions, photocrosslinking reactions, and photodecomposition reactions have been proposed (see, for example, Non-Patent Document 1, Patent Document 1, and Patent Document 2). [Prior Art 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 Document 1] "Liquid Crystal Photoalignment Film", Functional Materials, November 1997, Vol.17, No.11, pp.13-22 [Summary of the Invention]

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

[0007] In recent years, with the increasing performance of liquid crystal display (LCD) elements, in addition to their application in large-screen and high-resolution LCD TVs, applications in automotive applications are also being explored, such as car navigation systems, dashboards, surveillance cameras, and medical camera screens. Therefore, the requirements for LCD elements, especially high resolution and high performance, are even higher, and for liquid crystal alignment films, better characteristics of various LCD elements are required.

[0008] Furthermore, as liquid crystal display elements become larger, slight variations in the twist angle of the liquid crystal within the surface of the liquid crystal display element due to variations in the manufacturing process gradually begin to occur. Such variations result in uneven brightness within the surface of the liquid crystal display element when displaying black, causing a decrease in the quality of the liquid crystal display element.

[0009] Furthermore, considering the viewpoint that simultaneously meets all the above characteristics, some people also consider the method of mixing two or more polymers with different characteristics. However, depending on the type of polymer, there may be a situation where the polymer with high affinity to the substrate moves to the lower layer and other polymers move to the upper layer, which is called insufficient layer separation. This makes it impossible to obtain a liquid crystal display element that fully meets the requirements.

[0010] In view of the above circumstances, the present invention aims to provide a liquid crystal alignment agent that exhibits low variation (non-uniformity) in the torsion angle of the liquid crystal within the liquid crystal alignment film surface, and which can still form a liquid crystal alignment film with high layer separation even when using two or more polymers, and a liquid crystal display element having the liquid crystal alignment film. (Solution to the problem)

[0011] In order to achieve the above-mentioned problem, the inventors of this case have made great efforts to study and found that liquid crystal alignment agents containing polymers of novel diamines with specific structures are effective in achieving the above-mentioned objective, and thus the present invention was completed.

[0012] This invention relates to a liquid crystal alignment agent, characterized by containing a polymer (P), which is selected from at least one group consisting of a polyimide precursor obtained using a diamine component containing a diamine (O) represented by the following formula (DA) and a polyimide that is a polyimide derivative of the polyimide precursor. This invention also relates to a liquid crystal alignment film obtained by the liquid crystal alignment agent and a liquid crystal display element having the liquid crystal alignment film. [Chemical 1] Z 1 independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. The hydrogen atoms possessed by the aforementioned alkyl, alkenyl, or alkynyl groups may also be replaced by a monovalent group. Any hydrogen atom on the benzene ring bonded to the amino groups at both ends may also be replaced by a monovalent group. A represents a divalent organic group (a) of any carbon-carbon bond in an alkyl group having 4 to 10 carbon atoms, satisfying either of the following conditions (1) and (2). Furthermore, in the following conditions (1) and (2), *1 is bonded to a carbon atom of the alkyl group, and this carbon-carbon bond is selected from the carbon-carbon bonds forming the main chain of the polymer (P). (1) "*1-N(Boc)-*1" is inserted between carbon-carbon bonds at positions 2 or more; (2) "*1-N(Boc)-C(=O)-N(R)-*1" is inserted between carbon-carbon bonds at position 1 or more, where R represents a hydrogen atom or a monovalent organic group, and Boc represents a third butoxycarbonyl group. In this invention, halogen atoms may include fluorine, chlorine, bromine, iodine, etc. Boc represents a third butoxycarbonyl group. (Effects of the Invention)

[0013] According to the present invention, a liquid crystal alignment agent can be provided that has small variation (non-uniformity) of the torsion angle of liquid crystal within the liquid crystal alignment film surface and can form a liquid crystal alignment film with high layer separation even when two or more polymers are used; a liquid crystal alignment film obtained by the liquid crystal alignment agent; a high-performance liquid crystal display element having the liquid crystal alignment film; and novel diamines and polymers used in the manufacture of them.

[0014] The mechanism by which the above-mentioned effects of the present invention are obtained may not be clear, but it is generally presumed to be as follows. It is believed that due to the oxyaniline structure contained in the diamine (0) of the present invention, a liquid crystal alignment film with small variation in the torsion angle of the liquid crystal can be obtained. When two or more polymers are used, the polymer containing the diamine (0) is easily concentrated on the film surface due to the hydrophobicity of the Boc group, thus achieving high layer separation performance, and therefore the above-mentioned effects can be obtained.

Implementation Method

[0015] <Specific Diamine> The liquid crystal alignment agent of the present invention, as described above, is characterized by containing a polymer (P), which is selected from at least one of the group consisting of a polyimide precursor obtained by using a diamine component containing a diamine (O) represented by the following formula (DA) (also referred to as a specific diamine in the present invention) and a polyimide of a polyimide precursor. [Chemical 2] In the above formula (DA), A and Z1 are as defined above.

[0016] Considering the viewpoint of obtaining high liquid crystal alignment, the number of carbon atoms in the alkyl group of A in the above formula (DA) is preferably 6 to 10. The alkyl group of A in the above formula (DA) can be either linear or branched, but considering the viewpoint of ideally obtaining the effect of the present invention, linear alkyl groups are preferred.

[0017] The hydrogen atom of the alkyl, alkenyl, or alkynyl group in formula (DA) above may also be replaced by a monovalent group, such as a halogen atom, carboxyl group, hydroxyl group, cyano group, nitro group, etc. Among them, a halogen atom is preferred. In formula (DA) above, Z1 is preferably a hydrogen atom or a methyl group.

[0018] The monovalent organogroup R in the above "*1-N(Boc)-C(=O)-N(R)-*1" may 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 Boc group, or a monovalent organogroup in which one of the hydrogen atoms of such groups is replaced by at least one of a halogen atom and a hydroxyl group. R is preferably a hydrogen atom or a Boc group.

[0019] The hydrogen atoms on the benzene ring bonded by the amino groups at both ends in the above formula (DA) can also be replaced by monovalent groups, such as halogen atoms, methyl, methoxy, carboxyl, hydroxy, cyano, nitro, etc. Among them, halogen atoms, methyl, or methoxy are preferred.

[0020] In the above formula (DA), considering the viewpoint of obtaining high liquid crystal alignment, the two amine groups are preferably para-positioned relative to the divalent organic groups that link the benzene ring.

[0021] From the perspective of ideally obtaining the effect of the present invention, A in the above formula (DA) is preferably in the following form. Furthermore, n1, n1', n1”, n2, n2', n3, n3', and n3” independently represent integers greater than or equal to 1. The sum of n1, n1', and n1” is 4 to 10, the sum of n2 and n2' is 4 to 10, and the sum of n3, n3', and n3” is 4 to 10. Furthermore, in the following forms, R is synonymous with R in the above "*1-N(Boc)-C(=O)-N(R)-*1". When multiple R exist, they are independently defined as described above. *-(CH 2) n1-N(Boc)-(CH 2) n1'-N(Boc)-(CH 2) n1”-*, *-(CH 2) n2-N(Boc)-C(=O)-N(R)-(CH 2) n2'-*, *-(CH 2) n3-N(Boc)-C(=O)-N(R)-(CH 2) n3'-N(R)-C(=O)-N(Boc)-(CH 2) n3”-*.

[0022] Ideal examples of the above formula (DA) can be listed as the following formulas (dA-1) to (dA-2). [Chemical 3] In the above formula, Z1, R, n1, n1', n1”, n2 and n2' are each as defined above. Any hydrogen atom on the benzene ring bonded by the amino groups at both ends can also be replaced by a monovalent group. The aforementioned monovalent groups can be listed as monovalent groups that can replace the hydrogen atoms on the benzene ring bonded by the amino groups at both ends of the above formula (DA).

[0023] (Polymer (P)) The polymer (P) contained in the liquid crystal alignment agent of the present invention is a polyimide precursor obtained using a diamine component containing the above-mentioned diamine (0), or a polyimide of a polyimide precursor. The polyimide precursor is a polymer that can be obtained by amide-modifying polyamides, polyamide esters, etc. Polymer (P) can be used alone or in combination of two or more. The polymer (P) can also be a polymer having at least one repeating unit selected from the group consisting of repeating units (p1) represented by the following formula (1) and amide-modified structural units of the repeating unit (p1). [Chemical 4] In formula (1), X1 represents a tetravalent organic group. Y1 is a divalent organic group from which two amino groups have been removed from the above-mentioned specific diamine. R and Z each independently represent a hydrogen atom or a monovalent organic group. In the above formula (1), the monovalent organic groups of R and Z can be listed as monovalent hydrocarbon groups with 1 to 6 carbon atoms, monovalent groups A formed by replacing the methylene group of the hydrocarbon group with -O-, -S-, -CO-, -COO-, -COS-, -NR 3-, -CO-NR 3-, -Si(R 3) 2- (where R 3 is a hydrogen atom or a monovalent hydrocarbon group with 1 to 6 carbon atoms), -SO 2-, 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 by a halogen atom, hydroxyl, alkoxy, nitro, amino, mercapto, nitrosyl, 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 6 carbon atoms, alkenyl groups with 2 to 6 carbon atoms, alkynyl groups with 2 to 6 carbon atoms, or terbutoxycarbonyl groups, with alkyl groups with 1 to 3 carbon atoms being more preferred, and methyl groups being more desirable. For R and Z, from the viewpoint of ideally obtaining the effects of the present invention, it is more desirable for each to be a hydrogen atom or an alkyl group with 1 to 3 carbon atoms, with hydrogen atoms or methyl groups being more desirable. X1 in formula (1) above, for example, is a tetravalent organic group derived from a tetracarboxylic dianhydride or its derivative described later. An ideal example of a tetracarboxylic dianhydride or its derivative in X1 above can be listed as an ideal example of a tetracarboxylic dianhydride or its derivative that can be used in the synthesis of the polymer (P) described later. Polyamide (P'), which is a polyimide precursor of the polymer (P) above, can be obtained by polymerization of a diamine component containing the diamine (0) above with a tetracarboxylic acid component. The diamine (0) mentioned above can be used alone or in combination of two or more. The amount of diamine (0) used is ideally 5 mol% or more relative to the total diamine content, preferably 10 mol% or more, and even better 20 mol% or more.

[0024] The diamine component used in the manufacture of the above-mentioned polyamide (P') may also contain diamines other than diamine (0) (hereinafter also referred to as other diamines). When other diamines are used in combination with diamines other than diamine (0), it is preferable that the amount of diamine (0) used relative to the diamine component is 90 mol% or less, and even more preferable that it is 80 mol% or less.

[0025] The following are examples of other diamines, but are not limited to these. The aforementioned other diamines may be used alone or in combination of two or more. Examples include p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'- Diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, and the following formulas (dAL-1) to (d AL-10) represents diamines, 1,7-bis(4-aminophenoxy)heptane, 1,7-bis(3-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1,8-bis(3-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,9-bis(3-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, 1, 10-bis(3-aminophenoxy)decane, 1,11-bis(4-aminophenoxy)undecane, 1,11-bis(3-aminophenoxy)undecane, 1,12-bis(4-aminophenoxy)dodecane, 1,12-bis(3-aminophenoxy)dodecane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)benzene Phenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene, 1,2-bis(6-amino-2-naphthoxy)ethane, 1,2-bis(6-amino-2-naphthyl)ethane, 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine, 1,4-epoxyphenylbis(4-aminobenzoate), 1,4-epoxyphenylbis(3-aminobenzoate), 1,3-epoxyphenylbis(4-aminobenzoate), 1,3-epoxyphenylbis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4-aminophenyl)isophthalate, bis(3-aminophenyl)isophthalate (hereinafter, these diamines are also referred to as other diamines (a).Diamines with photoalignment groups, such as 4,4'-diaminoazobenzene or diaminodiphenylacetylene; diamines with photopolymerizable groups at the end, such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallyl aniline; diamines with free radical polymerization initiators, such as 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone and 2-(4-(2-hydroxy-2-methylpropionic acid)phenoxy)ethyl 3,5-diaminobenzoic acid; diamines with amide bonds, such as 4,4'-diaminophenoxyaniline; 1,3-bis(4-aminophenyl)urea; 1,3-bis( Diamines containing urea bonds, such as 4-aminobenzyl urea and 1,3-bis(4-aminophenylethyl)urea; 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(3-amino-4-methylphenyl)propane, 4,4'-diaminodiphenyl urea Phenylacetone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene; 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N-[3-(1H-imidazol-1-yl)propyl]3,5-diaminobenzylamine, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-4-methyl-2-azolyl]-aniline, or the following formula ( Diamines with a diphenylamine structure, such as those represented by formulas (z-1) to (z-13), including heterocyclic diamines, or 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-phenylenediamine, are diamines with a diphenylamine structure. These diamines have at least one nitrogen-containing structure selected from the group consisting of nitrogen-containing heterocycles, secondary amine groups, and tertiary amine groups (hereinafter also referred to as specific nitrogen-containing structures). (However, the molecule does not have an amine group that is bonded to a protecting group that is removed by heating and replaced by a hydrogen atom.)); 2,4-Diaminophenol, 3,5-Diaminophenol, 3,5-Diaminobenzyl alcohol, 2,4-Diaminobenzyl alcohol, 4,6-Diaminoresorcinol, 4,4'-Diamino-3,3'-dihydroxybiphenyl; 2,4-Diaminobenzoic acid, 2,5-Diaminobenzoic acid, 3,5-Diaminobenzoic acid, 4,4'-Diaminobiphenyl-3-carboxylic acid, 4,4'-Diaminodiphenylmethane-3-carboxylic acid, 1,2-bis(4-aminophenyl)ethane-3-carboxylic acid, 4,4'-Diaminobiphenyl-3,3'-dicarboxylic acid, 4,4'-Diaminobiphenyl-2,2'-dicarboxylic acid Acids, 3,3'-diaminobiphenyl-4,4'-dicarboxylic acid, 3,3'-diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid, 1,2-bis(4-aminophenyl)ethane-3,3'-dicarboxylic acid, 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid, and other diamines with carboxyl groups; 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 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; diamines of formulas (5-1) to (5-6) having the radical "-N(D)-" (D represents a protecting group that is removed and replaced by a hydrogen atom upon heating, preferably a carbamate protecting group, and more preferably a tert-butoxycarbonyl group. However, the specific diamines mentioned above are excluded.), cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanosteryl 3,6-bis(4-aminobenzoate) Diamines having a steroid skeleton, such as acetylcholestane; diamines represented by formulas (V-1) to (V-2); diamines having a siloxane bond, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; diamines with two amino groups bonded by any of the formulas (Y-1) to (Y-167) disclosed in International Publication No. 2018 / 117239.

[0026] [Chemical 5] In formulas (d AL-6) and (d AL-8), m1 and m2 are each independently defined as described above.

[0027] [Chemical 6]

[0028] [Chemical 7]

[0029] [Chemical 8]

[0030] [Chemical 9] In the above formula (V-1), m and n are each independent integers from 0 to 3, and satisfy 1≦m+n≦4. j is an integer of 0 or 1. X 1 represents -(CH 2) a- (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH 3)-, -NH-, -O-, -CH 2O-, -CH 2-OCO-, -COO-, or -OCO-. R 1 represents a fluorine atom, an alkyl group containing fluorine atoms with 1 to 10 carbon atoms, an alkoxy group containing fluorine atoms with 1 to 10 carbon atoms, an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, and an alkoxyalkyl group with 2 to 10 carbon atoms, etc., with a monovalent group. In the above equation (V-2), X2 represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. When two of m, n, X1, and R1 exist, each has the above definition independently.

[0031] Regarding the diamine component used in the manufacture of the above-mentioned polyamide (P'), from the viewpoint of ideally obtaining the effect of the present invention, it is preferable to contain at least one diamine selected from the group consisting of the other diamines (a) mentioned above.

[0032] When other diamines are used in addition to the above-mentioned diamine (0), the amount of the other diamine used is preferably 10 to 90 mol% relative to the total diamine content used in the manufacture of polymer (P), and more preferably 20 to 80 mol%.

[0033] (Tetracarboxylic acid component) When manufacturing the above-mentioned polyamide (P'), the tetracarboxylic acid component that reacts with the diamine component can be not only tetracarboxylic dianhydride, but also tetracarboxylic acid, tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters, or tetracarboxylic acid dialkyl ester dihalides and other derivatives of tetracarboxylic dianhydride.

[0034] The aforementioned tetracarboxylic dianhydrides or their derivatives may include acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, or derivatives thereof. It is preferable that the tetracarboxylic dianhydrides or their derivatives contain at least one substructure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring. In particular, it is ideal that the tetracarboxylic dianhydrides or their derivatives contain at least one structure selected from the group consisting of a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring. The aforementioned tetracarboxylic dianhydrides or their derivatives may be used alone or in combination of two or more. Furthermore, acyclic aliphatic tetracarboxylic dianhydrides are acid dianhydrides obtained by intramolecular dehydration of the four carboxyl groups bonded by a chain hydrocarbon structure. However, it is not necessary for them to be composed solely of a chain hydrocarbon structure; a portion of them may also have an alicyclic structure or an aromatic ring structure. Alicyclic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecularly dehydrating four carboxyl groups, including at least one carboxyl group linked by an alicyclic structure. However, none of these four carboxyl groups are bonded to an aromatic ring. Furthermore, they do not need to be composed solely of an alicyclic structure; a portion may also have a chain hydrocarbon structure or an aromatic ring structure. Aromatic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecularly dehydrating four carboxyl groups, including at least one carboxyl group linked by an aromatic ring. However, they do not need to be composed solely of an aromatic ring structure; a portion may also have a chain hydrocarbon structure or an alicyclic structure.

[0035] The tetracarboxylic acid component that can be used in the manufacture of the above-mentioned polyacrylic acid (P') is preferably a tetracarboxylic dianhydride or its derivatives (these are also collectively referred to as specific tetracarboxylic acid derivatives in this invention). Acyclic aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride; 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-difluoro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2, 3,4-Cyclopentanetetracarboxylic anhydride, 1,2,4,5-Cyclohexanetetracarboxylic anhydride, 3,3',4,4'-Dicyclohexyltetracarboxylic anhydride, 2,3,5-Tricarboxycyclopentylacetic anhydride, 4-(2,5-di-side-oxytetrahydrofuran-3-yl)tetrahydronaphthyl-1,2-dicarboxylic anhydride, 5-(2,5-di-side-oxytetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-di-side-oxytetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3 -Diketones, bicyclic [2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydrides, bicyclic [2.2.2]octane-2,3,5,6-tetracarboxylic dianhydrides, 2,4,6,8-tetracarboxylic bicyclic [3.3.0]octane-2:4,6:8-dianhydrides, etc., alicyclic tetracarboxylic dianhydrides; benzopyrene dianhydride, 3,3',4,4'-diphenyl ketone tetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4, Aromatic tetracarboxylic acid dianhydrides include 4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)-2,2-diphenylpropane dianhydride, ethylene glycol bis(triphenylene oxide) anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 4,4'-carbonyldiphthalic anhydride, 4,4'-(1,4-epylphenyldioxy)bis(phthalic anhydride), or 4,4'-(1,4-epylphenyldimethyl)bis(phthalic anhydride); in addition, tetracarboxylic acid dianhydrides described in Japanese Patent Application Publication No. 2010-97188 may be cited.

[0036] Ideal examples of the aforementioned specific tetracarboxylic acid derivatives include 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride. 1,3-Difluoro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5-(2,5-disideloxy) Tetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-disideloxytetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxylic acid bicyclo[3.3.0]octane-2:4,6:8-dianhydride, benzopyrenic acid Dihydric anhydride, 3,3',4,4'-diphenylketone tetracarboxylic anhydride, 3,3',4,4'-diphenylphenone tetracarboxylic anhydride, 1,4,5,8-naphthalene tetracarboxylic anhydride, 2,3,6,7-naphthalene tetracarboxylic anhydride, 3,3',4,4'-diphenyl ether tetracarboxylic anhydride, 3,3',4,4'-biphenyl tetracarboxylic anhydride, 2,2',3,3'-biphenyl tetracarboxylic anhydride, or derivatives thereof.

[0037] The ideal proportion of the above-mentioned specific tetracarboxylic acid derivatives used relative to the total tetracarboxylic acid components used is 10 mol% or more, 20 mol% or more is better, and 50 mol% or more is even better.

[0038] (Liquid Crystal Alignment Agent) The liquid crystal alignment agent of the present invention is a liquid composition consisting of a polymer (P) and other components used as needed, preferably dispersed or dissolved in a suitable solvent. The total content of the polymer component in the liquid crystal alignment agent of the present invention can be appropriately varied depending on the desired coating thickness. From the viewpoint of forming a uniform and defect-free coating, it is ideal to be 1% by mass or more relative to the total mass of the liquid crystal alignment agent; from the viewpoint of the storage stability of the solution, it is preferably 10% by mass or less. The content of the polymer (P) used in the present invention is ideally 1 to 100 parts by mass relative to 100 parts by mass of the total polymer contained in the liquid crystal alignment agent, more preferably 10 to 100 parts by mass, and even more preferably 20 to 100 parts by mass.

[0039] The liquid crystal alignment agent of the present invention may also contain polymers other than polymer (P). Specific examples of other polymers include polymers selected from the group consisting of: at least one polymer (also referred to as polymer (B) in the present invention) selected from the group consisting of a polyimide precursor obtained using a diamine component that does not contain the specific diamine mentioned above and a polyimide that is a polyimide derivative of the polyimide precursor; polysiloxanes; polyesters; polyamides; polyureas; polyorganosiloxanes; cellulose derivatives; polyacetals; polystyrene derivatives; poly(styrene-maleic anhydride) copolymers; poly(isobutylene-maleic anhydride) copolymers; poly(vinyl ether-maleic anhydride) copolymers; poly(styrene-phenylmaleimide) derivatives; and poly(meth)acrylates.

[0040] Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, SMA3000 (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). Among these, polymer (B) is more ideal from the perspective of reducing residual DC. The other polymers mentioned above can be used alone or in combination of two or more. The ideal proportion of the other polymers relative to the total 100 parts by mass of polymers contained in the liquid crystal alignment agent is 90 parts by mass or less, 10 to 90 parts by mass is better, and 20 to 80 parts by mass is more ideal. The content of the aforementioned polymer (P) may be 90 parts by mass or less, or 80 parts by mass or less, relative to the total 100 parts by mass of polymers contained in the liquid crystal alignment agent.

[0041] (Polymer (B)) Specific examples of the tetracarboxylic acid component used in the manufacture of the above-described polymer (B), including ideal examples, are the same compounds as those exemplified in polymer (P). It is preferable that the tetracarboxylic acid component used in the manufacture of polymer (B) contains a tetracarboxylic dianhydride or a derivative thereof having at least one substructure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring. The aforementioned specific tetracarboxylic acid derivative is even more preferable, and the most ideal example of the aforementioned specific tetracarboxylic acid derivative is most desirable. Furthermore, it is preferable that the amount of the aforementioned specific tetracarboxylic acid derivative used is 10 mol% or more relative to the total tetracarboxylic acid component used in the manufacture of polymer (B), more preferably 20 mol% or more, and even more preferably 50 mol% or more.

[0042] The diamine component used to obtain polymer (B) is, for example, the diamine exemplified by the polymer (P) described above. Preferably, it contains at least one diamine selected from the group consisting of: diamines having at least one group selected from the group consisting of urea bonds, amide bonds, carboxyl groups, and hydroxyl groups; 3,3'-diaminodiphenyl ether; 3,4'-diaminodiphenyl ether; 4,4'-diaminodiphenyl ether; diamines represented by formulas (dAL-1) to (dAL-10) above; and diamines having the aforementioned specific nitrogen-containing structure. The aforementioned diamine component may be used alone or in combination of two or more. When using the aforementioned specific diamine (b), it is preferable that its amount is 10 mol% or more of the total diamine component used in the manufacture of polymer (B), and more preferably 20 mol% or more. When using diamines other than specific diamines (b), it is ideal to use less than 90 mol% of all diamine components used in the manufacture of polymer (B), and even more ideal to use less than 80 mol%.

[0043] (Manufacturing of Polyacrylic Acid) Polyacrylic acid is manufactured by reacting a diamine component with a tetracarboxylic acid component in an organic solvent. The ideal ratio of the tetracarboxylic acid component to the diamine component in the polyacrylic acid manufacturing reaction is 0.5 to 2 equivalents of the anhydride group of the tetracarboxylic acid component relative to 1 equivalent of the amino group of the diamine component, more preferably 0.8 to 1.2 equivalents. Similar to conventional polycondensation reactions, the closer the equivalent of the anhydride group of the tetracarboxylic acid component is to 1 equivalent, the larger the molecular weight of the resulting polyacrylic acid becomes. The ideal reaction temperature for manufacturing polyacrylic acid is -20 to 150°C, more preferably 0 to 100°C. Furthermore, the ideal reaction time is 0.1 to 24 hours, more preferably 0.5 to 12 hours. Polyacrylic acid can be manufactured at any concentration. The concentration of polyacrylic acid is preferably 1–50% by mass, more preferably 5–30% by mass. The reaction is initially carried out at a high concentration, and solvent may be added thereafter.

[0044] Specific examples of the above-mentioned organic solvents include cyclohexanone, cyclopentanone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolidineone. Furthermore, when the polymer has high solvent solubility, solvents such as methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, or diethylene glycol monoethyl ether can be used.

[0045] (Manufacturing of polyamide esters) Polyamide esters can be obtained, for example, by the following known methods: [I] a method of reacting polyamide obtained by the above method with an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester with a diamine, [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine, etc.

[0046] (Manufacturing of Polyimide) Polyimide can be obtained by cyclizing (nitroimidizing) the aforementioned polyimide precursors such as polyamide or polyamide ester. Furthermore, the nitroimidization rate referred to in this specification is the proportion of nitroimide groups to the total amount of nitroimide groups and carboxyl groups (or their derivatives) derived from tetracarboxylic dianhydride or its derivatives. The nitroimidization rate does not necessarily have to be 100% and can be adjusted arbitrarily according to the application and purpose.

[0047] Methods for amide-imidizing polyimide precursors include thermal amide-imidization by directly heating a solution of the polyimide precursor, and catalytic amide-imidization by adding a catalyst to a solution of the polyimide precursor. The temperature at which the polyimide precursor is thermally amide-imidized in solution is preferably 100–400°C, more preferably 120–250°C, and it is preferable to drain the water generated during the amide-imidization reaction outside the system.

[0048] Catalytic amide formation of polyimide precursors can be carried out by adding an alkaline catalyst and an acid anhydride to a solution of the polyimide precursor, preferably at -20 to 250°C, more preferably at 0 to 180°C with stirring. The amount of alkaline catalyst is preferably 0.5 to 30 moles of the amide group, more preferably 2 to 20 moles, and the amount of acid anhydride is preferably 1 to 50 moles of the amide group, more preferably 3 to 30 moles. Examples of alkaline catalysts include pyridine, triethylamine, trimethylamine, tributylamine, or trioctylamine, among which pyridine is ideal due to its moderate alkalinity that facilitates the reaction. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, or phenylmethyltetrahydroquinone, among which acetic anhydride is preferred because it facilitates purification after the reaction. The amide ratio obtained by catalytic amide imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[0049] When recovering the polyimide precursor or polyimide generated from the reaction solution of the polyimide precursor or polyimide, the reaction solution is simply added to a solvent and allowed to precipitate. Examples of solvents used for precipitation include methanol, ethanol, isopropanol, acetone, hexane, butylceryl ketone, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. After filtration and recovery of the polymer obtained by adding it to the solvent and allowing it to precipitate, it can be dried at room temperature or under normal or reduced pressure, or by heating. Furthermore, if the recovered polymer is redissolved in an organic solvent and reprecipitated, repeating this operation 2 to 10 times can reduce impurities in the polymer. Ideally, the purification efficiency should be better if three or more solvents selected from alcohols, ketones, or hydrocarbons are used.

[0050] When manufacturing the polyimide precursor and polyimide of the present invention, a tetracarboxylic acid component containing tetracarboxylic acid dianhydride or its derivative, and a diamine component containing the aforementioned diamine, can also be used together with a suitable end-capping agent to manufacture an end-sealed polymer. The end-sealed polymer has 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. In the present invention, examples of the ends of the polyimide precursor and polyimide can be derived from amino groups, carboxyl groups, anhydride groups, or the groups of 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.

[0051] End-capping agents, such as: acetic anhydride, maleic anhydride, naphthalic anhydride, phthalic anhydride, itaconic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynylphthalic anhydride, etc.; dibutyl dicarbonate, diallyl dicarbonate, etc., dicarbonate ester compounds; acrylamide chloride, methyl... The diamines used include chlorocarbonyl compounds such as hydroxypropyl chloride and nicotinic chloride; monoamine compounds such as aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; and isocyanates with unsaturated bonds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, or 2-acryloyloxyethyl isocyanate and 2-methacryloyloxyethyl isocyanate. The preferred ratio of the capping agent to the total 100 moles of the diamine components used is 0.01 to 20 moles, and more preferably 0.01 to 10 moles.

[0052] The weight-average molecular weight (Mw) of the polyimide precursor and polyimide, determined by gel permeation chromatography (GPC) based on polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC, is preferably 15 or less, more preferably 10 or less. Within this molecular weight range, good liquid crystal alignment of the liquid crystal display element can be ensured.

[0053] The organic solvent contained in the liquid crystal alignment agent of the present invention is not particularly limited as long as it can uniformly dissolve the polymer (P) and other polymers added as needed. 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-imidazolidineone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropionic acid, 3-butoxy-N,N-dimethyl... N-methyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-(3-methoxypropyl)-2-pyrrolidone, N-(2-ethoxyethyl)-2-pyrrolidone, N-(4-methoxybutyl)-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone (all collectively referred to as good solvents) are preferred. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionic acid, 3-butoxy-N,N-dimethylpropionic acid, 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, 20-90% by mass is even better, and 30-80% by mass is particularly ideal.

[0054] Furthermore, the organic solvent contained in the liquid crystal alignment agent is preferably a mixed solvent that combines the aforementioned solvent with a solvent (also known as a poor solvent) that improves the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent. Specific examples of the poor solvent used are as follows, but are not limited to these. The content of the poor solvent is ideally 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 80% by mass, and especially preferably 20 to 70% by mass. The type and content of the poor solvent can be appropriately selected according to the coating apparatus, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

[0055] Undesirable solvents, such as: diisopropyl ether, diisobutyl ether, diisobutylmethanol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 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-butoxy) (2-(2-ethoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol diacetate, 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.

[0056] Among them, diisobutylmethanol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, or diisobutyl ketone are preferred.

[0057] As for the ideal combination of good and bad solvents, examples 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, and N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate and dipropylene glycol. Monomethyl 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 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 N-methyl-2-pyrrolidone 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-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether with diisopropyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone 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, N-ethyl-2 - Pyrrolidone with N,N-dimethyllactamine and diisobutyl ketone, N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate, γ-butyrolactone with ethylene glycol monobutyl ether acetate and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone with ethylene glycol monobutyl ether acetate and propylene glycol dimethyl ether, N-methyl-2-pyrrolidone with 4-methyl-2-pentyl acetate and ethylene glycol monobutyl ether, N-ethyl-2-pyrrolidone with cyclohexyl acetate and 4-hydroxy-4-methyl-2-pentanone, cyclohexanone with propylene glycol monomethyl ether, cyclopentanone with propylene glycol monomethyl ether, N-methyl-2-pyrrolidone with cyclohexanone and propylene glycol monomethyl ether, etc.

[0058] (Liquid Crystal Alignment Agent) The liquid crystal alignment agent of the present invention may also contain other components (hereinafter also referred to as additive components) in addition to the above-mentioned polymer (P), the other polymers mentioned above, and the above-mentioned organic solvent. These additive components may include, for example, at least one crosslinking compound selected from the group consisting of crosslinking compounds having at least one substituent selected from ethylene oxide, propylene oxide, terminal isocyanate group, acezolinyl group, cyclocarbonate group, hydroxyl group, and alkoxy group, and crosslinking compounds having polymerizable unsaturated groups; functional silane compounds; metal chelate compounds; curing accelerators; surfactants; antioxidants; sensitizers; preservatives; and compounds used to adjust the dielectric constant and resistance of the obtained liquid crystal alignment film.

[0059] Ideal specific examples of the above-mentioned crosslinking compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetracyclooxypropyl-2,4-hexanediol, and EPIK. OTE828 (manufactured by Mitsubishi Chemical Corporation) and other bisphenol A type epoxy resins, EPIKOTE807 (manufactured by Mitsubishi Chemical Corporation) and other bisphenol F type epoxy resins, YX-8000 (manufactured by Mitsubishi Chemical Corporation) and other hydrogenated bisphenol A type epoxy resins, YX6954BH30 (manufactured by Mitsubishi Chemical Corporation) and other epoxy resins containing a biphenyl backbone, EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.) and other phenolic varnish type epoxy resins. EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.) and other (ortho, meta, para) cresol phenolic varnish epoxy resins; TEPIC (manufactured by Nissan Chemical Co., Ltd.) and other trichloropropylene isocyanate; CELLOXIDE2021P (manufactured by Daicel Chemical Co., Ltd.) and other alicyclic epoxy resins; N,N,N',N'-tetracyclooxypropyl-methylenediamine, 1,3-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, or N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and other compounds containing tertiary nitrogen atoms; tetra(epoxypropoxymethyl)methane and other compounds having two or more ethylene oxide groups; compounds having two or more propylene oxide groups as described in paragraphs

[0170] to

[0175] of WO2011 / 132751; CORONATEAP Stable Compounds containing terminal isocyanate groups, such as M, CORONATE2503, 2515, 2507, 2513, 2555, MILLIONATEMS-50 (all manufactured by Tosoh Corporation), TAKENATEB-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, and B-882N (all manufactured by Mitsui Chemicals Corporation); Compounds containing an acezoline group, such as 2,2'-bis(2-acezoline), 2,2'-bis(4-methyl-2-acezoline), 2,2'-bis(5-methyl-2-acezoline), 1,2,4-tris(2-acezoline)-benzene, and compounds containing an acezoline group, such as those produced by EPOCROS (Nippon Shokubai Co., Ltd.); and compounds containing a cyclic carbonate group, as described in paragraphs

[0025] to

[0030] and

[0032] of WO2011 / 155577.Compounds containing hydroxyl or alkoxy groups, such as N,N,N',N'-tetra(2-hydroxyethyl)hexamethylenediamine, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxyphenyl)propane, and 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane; and compounds represented by glycerol mono(meth)acrylate, glycerol di(meth)acrylate (1,2-, 1,3-component mixture), glycerol tri(meth)acrylate, glycerol 1,3-diglyceric acid di(meth)acrylate, pentaerythritol tri(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate, and hexaethylene glycol mono(meth)acrylate. The content of the aforementioned crosslinking compound is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, and more preferably 0.1 to 20 parts by mass.

[0060] Examples of compounds used to adjust dielectric constant and resistance include monoamines such as 3-pyridinemethylamine, which are aromatic heterocyclic compounds containing nitrogen atoms. The content of the monoamine containing the aromatic heterocyclic compound containing nitrogen atoms is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, and more preferably 0.1 to 20 parts by mass.

[0061] Ideal specific examples of the above-mentioned functional silane compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane. Oxysilanes, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-propenyloxypropyltrimethoxysilane, tris(3-(trimethoxysilyl)propyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, etc. The content of functional silane compounds is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of polymer components contained in the liquid crystal alignment agent, and more preferably 0.1 to 20 parts by mass.

[0062] 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 considering viscosity, volatility, etc., and is preferably 1 to 10% by mass. The particularly 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 particularly preferred, thereby making the solution viscosity 12 to 50 mPa·s particularly preferred. When using inkjet printing, a solid component concentration of 1 to 5% by mass is particularly preferred, thereby making the solution viscosity 3 to 15 mPa·s particularly preferred. The temperature for preparing the liquid crystal alignment agent is preferably 10 to 50°C, more preferably 20 to 30°C.

[0063] (Liquid Crystal Alignment Film and Liquid Crystal Display Element) The liquid crystal display element of the present invention comprises a liquid crystal alignment film formed using the above-described liquid crystal alignment agent. The operating mode of the liquid crystal display element is not particularly limited, and various operating modes can be adopted, such as: TN mode, STN mode, vertical alignment mode (including VA-MVA mode, VA-PVA mode, etc.), in-plane switching mode (IPS mode, FFS mode), optically compensated bending mode (OCB mode), etc.

[0064] The liquid crystal display element of the present invention can be manufactured by, for example, a method including the following steps (1) to (4), a method including steps (1) to (2) and (4), a method including steps (1) to (3), (4-2) and (4-4), or a method including steps (1) to (3), (4-3) and (4-4).

[0065] <Step (1): Step of coating liquid crystal alignment agent on substrate> Step (1) is the step of coating liquid crystal alignment agent on substrate. The specific example of step (1) is as follows. On one side of a substrate with a patterned transparent conductive film, a liquid crystal alignment agent is coated using a suitable coating method such as roll coating, spin coating, printing, inkjet coating, or spray coating. Here, the material of the substrate is not particularly limited as long as it is a substrate with high transparency, and materials such as glass, silicon nitride, acrylic, and polycarbonate can be used together. In addition, in reflective liquid crystal display elements, if it is only a single-sided substrate, an opaque material such as silicon wafer can also be used, and the electrodes can also be made of materials that reflect light, such as aluminum. In addition, when manufacturing liquid crystal display elements of IPS or FFS type, a substrate with electrodes composed of a transparent conductive film or metal film patterned into a comb shape and a counter substrate without electrodes are used. An IPS substrate, used as a comb-electrode substrate in an IPS-type liquid crystal display element, includes, for example: a substrate; a plurality of linear electrodes formed and arranged in a comb-like pattern on the substrate; and a liquid crystal alignment film formed on the substrate in such a way as to cover the linear electrodes. Similarly, an FFS substrate, used as a comb-electrode substrate in an FFS-type liquid crystal display element, includes, for example: a substrate; a surface electrode formed on the substrate; an insulating film formed on the surface electrode; a plurality of linear electrodes formed and arranged in a comb-like pattern on the insulating film; and a liquid crystal alignment film formed on the insulating film in such a way as to cover the linear electrodes.

[0066] More ideal examples of methods for coating liquid crystal alignment agents onto a substrate and forming a film include printing methods such as screen printing, offset printing, or flexographic printing, spin coating, inkjet printing, or spray coating. Among these, coating and film forming methods using flexographic printing, spin coating, or inkjet printing are ideally applicable.

[0067] <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. The specific example of step (2) is as follows. After the liquid crystal alignment agent is coated on the substrate in step (1), the solvent can be evaporated by heating means such as a hot plate, a thermal cycling oven or an IR (infrared) oven, or the thermal imidization of polyimide precursors represented by polyacrylic acid can be performed. The drying and calcination steps after coating the liquid crystal alignment agent can be performed at any temperature and time, and can be performed multiple times. The calcination temperature of the liquid crystal alignment agent can be, for example, 40 to 180°C. Considering the viewpoint of shortening the processing time, it can also be performed at 40 to 150°C. The calcination time is not particularly limited and can be 1 to 10 minutes or 1 to 5 minutes. When performing thermal acetamidization of polyimide precursors, such as polyamide, an additional calcination step at 150–300°C or 150–250°C may be added after the above steps. The calcination time is not particularly limited, for example, 5–40 minutes, but preferably 5–30 minutes. If the film thickness after calcination is too thin, the reliability of the liquid crystal display element may sometimes decrease; therefore, 5–300 nm is ideal, and 10–200 nm is even more ideal.

[0068] <Step (3): Step of aligning the film obtained in step (2)> Step (3) is a step of aligning the film obtained in step (2) as appropriate. That is, in horizontal alignment type liquid crystal display elements such as IPS or FFS, the coating is subjected to alignment capability imparting treatment. On the other hand, in vertical alignment type liquid crystal display elements such as VA or PSA (Polymer Sustained Alignment), the formed coating can be used directly as a liquid crystal alignment film, or the coating can be subjected to alignment capability imparting treatment. Alignment treatment methods for liquid crystal alignment films include rubbing alignment treatment and photoalignment treatment. Photoalignment treatment methods include irradiating the surface of the above-mentioned film with radiation that is polarized in a certain direction, and then heating the film as appropriate to impart liquid crystal alignment properties (also known as liquid crystal alignment capability). As for radiation, ultraviolet light or visible light with wavelengths of 100 to 800 nm can also be used. Preferably, it is ultraviolet light with a wavelength of 100–400 nm, and more preferably, it is ultraviolet light with a wavelength of 200–400 nm.

[0069] The ideal radiation dose is 1 to 10,000 mJ / cm², with 100 to 5,000 mJ / cm² being more ideal. Furthermore, to improve liquid crystal alignment, the substrate with the film can be heated at 50 to 250°C while being irradiated with radiation. The liquid crystal alignment film prepared in this manner enables the liquid crystal molecules to be stably aligned in a specific direction.

[0070] Furthermore, the coating film irradiated with polarized radiation as described above, or the coating film that has undergone friction alignment treatment, may also be subjected to contact treatment using water or a solvent. Also, the film that has undergone the above alignment treatment may be subjected to heat treatment without contact treatment. Furthermore, the film that has undergone the above contact treatment may be further subjected to heat treatment.

[0071] 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. The solvent can be one type or a combination of two or more.

[0072] The temperature for heat treatment of the above-mentioned radiation-irradiated coating is preferably 50-300°C, and even more preferably 120-250°C. The heat treatment time is preferably 1-30 minutes.

[0073] <Step (4): 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 the liquid crystal alignment film systems facing each other, with a gap (cell gap) between them. Next, use a sealant to bond the periphery of the two substrates together, inject the liquid crystal composition to fill the cell gap separated by the substrate surface and the sealant, and after contacting the film surface, seal the injection hole. There are no special restrictions on the liquid crystal composition, and various liquid crystal compositions containing at least one liquid crystal compound (liquid crystal molecule) and having a positive or negative dielectric constant anisotropy can be used. Furthermore, liquid crystal compositions with a positive dielectric constant anisotropy are referred to as positive liquid crystals, and liquid crystal compositions with a negative dielectric constant anisotropy are referred to as negative liquid crystals. The aforementioned liquid crystal composition 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 groups, cycloalkanes, cycloalkenes, steroid skeletons, benzene rings, or naphthyl rings. It may also contain compounds with two or more rigid sites (liquid crystal proto-skeletons) exhibiting liquid crystal properties within the molecule (e.g., rigid biphenyl structures, or biphenyl structures linked by alkyl groups forming a dual liquid crystal proto-skeleton). The liquid crystal composition may be a nematic phase liquid crystal composition, a lamellar phase liquid crystal composition, or a cholesterol phase liquid crystal composition. Furthermore, from the viewpoint of improving liquid crystal alignment, additives may be added to the aforementioned liquid crystal composition. Such additives include photopolymerizable monomers such as compounds with polymerizable groups (e.g., methacrylic acid group); optically active compounds (e.g., Merck S-811); antioxidants; UV absorbers; pigments; defoamers; polymerization initiators; or polymerization inhibitors. Positive liquid crystals include Merck's ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081. Negative liquid crystals include Merck's MLC-6608, MLC-6609, MLC-6610, MLC-6882, MLC-6886, MLC-7026, MLC-7026-000, MLC-7026-100, and MLC-7029. Furthermore, in PSA mode, liquid crystals containing compounds with polymerizable groups can be exemplified by Merck's MLC-3023.

[0074] Furthermore, the second method is called the ODF (One Drop Fill) method. A UV-curable sealant, for example, is applied to a predetermined location on one of the two substrates on which a liquid crystal alignment film has been formed. 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 together with the liquid crystal alignment films facing each other, and then the liquid crystal composition is pressed onto the entire surface of the substrate, making it contact the film surface. Then, the entire surface of the substrate is irradiated with UV light to harden the sealant. When performing either method, it is advisable to further remove the flow alignment during liquid crystal filling by heating the liquid crystal composition to a temperature at which it becomes isotropic and then slowly cooling it to room temperature. Furthermore, when performing a rubbing treatment on the coating, the two substrates are arranged facing each other at a predetermined angle, for example, orthogonal or antiparallel, according to the rubbing directions in each coating. The sealant can be, for example, epoxy resin containing a hardener and alumina balls as spacers. Liquid crystals can be categorized into nematic liquid crystals and lamellar liquid crystals, with nematic liquid crystals being preferred.

[0075] The liquid crystal alignment agent of the present invention is also suitable for use in liquid crystal display elements (PSA-type liquid crystal display elements) manufactured by having a liquid crystal layer between a pair of substrates having electrodes, and by disposing a liquid crystal composition containing a polymeric compound that polymerizes due to at least one of active energy rays and heat between the pair of substrates, applying a voltage between the electrodes, and polymerizing the polymeric compound by irradiation with active energy rays and heating. Furthermore, the liquid crystal alignment agent of the present invention is also suitable for use in liquid crystal display elements (SC-PVA-type liquid crystal display elements) manufactured by having a liquid crystal layer between a pair of substrates having electrodes, and by disposing a liquid crystal alignment film containing a polymeric group that polymerizes due to at least one of active energy rays and heat between the pair of substrates, and applying a voltage between the electrodes.

[0076] <Step (4-2): Case of PSA liquid crystal display element> Except for injecting or dropping dots containing liquid crystal composition containing polymeric compound, the same procedure as described above (4) is performed. Polymeric compound, for example, a polymeric compound having one or more polymeric unsaturated groups such as acrylate group or methacrylate group in its molecule.

[0077] <Step (4-3): Case of SC-PVA liquid crystal display element> After performing the same procedure as above (4), the method of manufacturing liquid crystal display element by ultraviolet irradiation as described later can also be used. According to this method, as in manufacturing the above-mentioned PSA liquid crystal display element, a liquid crystal display element with excellent response speed can be obtained with a small amount of light irradiation. The compound having a polymerizable group can be a compound having one or more of the above-mentioned polymerizable unsaturated groups in the molecule, and its content is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the total polymer component, more preferably 1 to 20 parts by mass. Furthermore, the polymer used in the liquid crystal alignment agent can also have the above-mentioned polymerizable group. Such a polymer is, for example, a polymer obtained by reacting a diamine component containing a diamine with the above-mentioned photopolymerizable group at the end.

[0078] <Step (4-4): Step of irradiating with ultraviolet light> The liquid crystal cells are irradiated with light while applying a voltage between the conductive films on the substrate obtained in (4-2) or (4-3) above. The applied voltage is, for example, DC or AC of 5 to 50V. The irradiated light can be, for example, ultraviolet light containing wavelengths of 150 to 800 nm and visible light, but it is preferable to use ultraviolet light containing wavelengths of 300 to 400 nm. The light source for the irradiation light can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonant lamp, a xenon lamp, an excimer laser, etc. The irradiation intensity is preferably 1,000 to 200,000 J / m², more preferably 1,000 to 100,000 J / m².

[0079] Furthermore, as needed, a liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include polarizing plates made by sandwiching a polarizing film called an "H-film" (which extends and aligns polyvinyl alcohol on one side while absorbing iodine) with a cellulose acetate protective film, or polarizing plates composed of the H-film itself. [Example]

[0080] The following examples illustrate the present invention in more detail, but the present invention is not limited thereto. The abbreviations of the compounds used and the methods for measuring their properties are as follows.

[0081] (Organic solvent) NMP: N-methyl-2-pyrrolidone; BCS: Butylceroxose (ethylene glycol monobutyl ether); THF: Tetrahydrofuran; DMF: N,N-dimethylformamide

[0082] (Acid dianhydrides) CA-1~CA-2: Each is a compound represented by the formula (CA-1)~(CA-2) [Chemistry 10]

[0083] (Diamine) DA-1 to DA-10: Each is a compound represented by the formula (DA-1) to (DA-10). The diamines included in the specific diamine range of the present invention are compounds represented by the formula (DA-1) to (DA-2). [Chemical 11]

[0084] (Reagent) Boc 2O: Dibutyl dicarbonate

[0085] [Determination of molecular weight] The molecular weight was determined using the following room temperature GPC (gel permeation chromatography) apparatus, and Mn and Mw were calculated based on the conversion values ​​of polyethylene glycol and polyethylene oxide. GPC apparatus: GPC-101 (manufactured by Showa Denko Corporation), columns: GPC KD-803 and GPC KD-805 (manufactured by Showa Denko Corporation) in series, column temperature: 50°C, dissolution solution: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr·H₂O) 30 mmol / L, phosphoric acid·anhydrous crystals (orthophosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L), flow rate: 1.0 mL / min. Standard samples used for the measurement 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).

[0086] [Synthesis of Monomers] DA-1 and DA-2 are novel compounds not disclosed in the literature. The synthesis method is described in detail below. -OTMS represents tetramethylsiloxy.

[0087] The products described in the following monomer synthesis examples were identified by 1H-NMR analysis (analytical conditions are as follows). Apparatus: Fourier transform superconducting nuclear magnetic resonance (FT-NMR) device "AVANCE III" (BRUKER) 500MHz. Solvent: Deuterated dimethyl monoxide (DMSO-d6), Standard substance: Tetramethylsilane

[0088] (Synthesis Example 1: Synthesis of DA-1) DA-1 was synthesized according to the following pathway. [Chemistry 12]

[0089] N,N'-bis(2-hydroxyethyl)ethylenediamine (25.0 g, 0.169 mol) was added to THF (200 g) and stirred at 50 °C. A solution of Boc 2O (75.5 g, 0.346 mol) diluted with THF (50 g) was added dropwise, and the mixture was heated and stirred for 20 hours to allow the reaction to proceed. After the reaction was complete, the solution was cooled to room temperature (25 °C), concentrated, and acetonitrile (118 g) was added. The mixture was stirred at room temperature (25 °C) for 30 minutes, and the precipitated crystals were filtered off. The obtained crystals were dried at 40 °C to obtain DA-1-1. Alternatively, the filtrate was concentrated, and acetonitrile (59 g) was added again. The mixture was stirred for 30 minutes, and the precipitated crystals were filtered off to recover the crystals. The obtained crystals were dried to obtain DA-1-1 (total yield: 54.4 g, 0.156 mol, yield: 92%). The solid was confirmed to be DA-1-1 by the following 1H-NMR results. 1H-NMR (500 MHz), in DMSO-d 6: δ (ppm) = 4.65 (br, 2H), 3.45 (s, 4H), 3.28 (s, 4H), 3.18–3.16 (m, 4H), 1.39–1.38 (m, 18H) [Chem. 13]

[0090] Sodium hydride (13.8 g, dispersed in 60%-flowing paraffin) and DMF (200 g) were added to a flask, and the mixture was cooled and stirred in an ice bath at 0°C. A solution of DA-1-1 (50.0 g, 0.143 mol) obtained above, dissolved in DMF (300 g), was added dropwise, and the mixture was stirred for 30 minutes. Next, a solution of 4-fluoronitrobenzene (42.5 g, 0.301 mol) dissolved in DMF (50 g) was added dropwise. After the addition was complete, the mixture was stirred at room temperature (25°C) for 6 hours to allow the reaction to proceed. Methanol (100 g) was added to the reaction mixture to deactivate excess sodium hydride. The reaction mixture was then added to methanol (1550 g) and stirred to allow crystals to precipitate. The crystals were separated by filtration and washed with methanol (150 g). The resulting crystals were dried at 40 °C to obtain DA-1-2 (yield: 66.0 g, 0.112 mol, yield: 78%). The solid was confirmed as DA-1-2 by the following 1H-NMR results. 1H-NMR (500 MHz), in DMSO-d 6: δ (ppm) = 8.18 (d, J = 7.5 Hz, 4H), 7.15 (d, J = 9.0 Hz, 4H), 4.23 (s, 4H), 3.55 (t, 4H), 3.38 (s, 4H), 1.38 (s, 9H), 1.35 (s, 9H) [Chem. 14]

[0091] THF (989g) was added to the DA-1-2 (65.9g, 0.112mol) obtained above for nitrogen substitution. Then, carbon-supported palladium (5% Pd carbon powder (containing water) K type, manufactured by NE Chemcat) (5.27g) was added, and nitrogen substitution was performed again. A hydrogen-filled gas sampling bag (Tedlar bag) was installed, and the mixture was heated and stirred at 45°C for 18 hours to allow the reaction to proceed. As the reaction proceeded, the crystals dissolved, and then a large amount of crystals precipitated again from the solution. Therefore, DMF (1318g) was added to dissolve the crystals. The mixture was filtered using a Kiriyama funnel, and the filtrate was then passed through a membrane filter to remove the carbon-supported palladium. By concentrating the filtrate, crude DA-1 was obtained. Methanol (200g) was added to the crude DA-1, and the mixture was stirred in a slurry state at room temperature (25°C) and filtered. The obtained crystals were dried to obtain DA-1 (yield: 45.2 g, 0.0852 mol, yield: 76%). The solid was confirmed as DA-1 by the following 1H-NMR results: 1H-NMR (500 MHz), in DMSO-d 6: δ (ppm) = 6.64 (d, J = 7.5 Hz, 4H), 6.49 (d, J = 7.5 Hz, 4H), 4.59 (s, 4H), 3.90 (s, 4H), 3.43 (s, 4H), 3.35 (s, 4H), 1.39 (s, 9H), 1.37 (s, 9H)

[0092] (Synthesis Example 2: Synthesis of DA-2) DA-2 was synthesized according to the following pathway. [Chemistry 15]

[0093] In a 1L four-necked flask under nitrogen atmosphere, 3-amino-1-propanol (30.0 g, 399 mmol), dichloromethane (600 g), and triethylamine (60.7 g, 600 mmol) were added. After cooling to 0°C, trimethylsilyl chloride (47.8 g, 440 mmol) was added dropwise over 30 minutes. After the addition was complete, carbonyl diimidazole (31.1 g, 192 mmol) was added after stirring at 0°C for 1 hour to initiate the reaction. After stirring at 0°C for 1 hour, the reaction was further stirred at room temperature for 48 hours to complete the reaction. The reaction mixture was transferred to a separatory funnel and washed twice with water (300 g). The organic layer was dried with magnesium sulfate (40.0 g) and the magnesium sulfate was removed by filtration. The obtained filtrate was concentrated and then dried under vacuum (40°C) to obtain an oily DA-2-1 (60.3 g, 188 mmol, yield 98.0%, colorless and transparent). [Chem. 16]

[0094] DA-2-1 (41.2 g, 129 mmol), 4-nitrofluorobenzene (39.8 g, 282 mmol), potassium hydroxide (17.2 g, 307 mmol), and NMP (380 g) were added to a 1 L four-necked flask under nitrogen atmosphere and stirred at 0 °C for 24 hours to carry out the reaction. After the reaction, water (460 g) cooled to 0 °C was added to the reaction solution. The wet filter cake obtained by filtering the precipitated solid was washed three times with water (300 g) and then three times with acetonitrile (300 g). The obtained solid was dried to obtain DA-2-2 (38.9 g, 93.0 mmol, yield 72.1%, yellow solid). [Chem. 17]

[0095] Under nitrogen atmosphere, DA-2-2 (34.0 g, 81.3 mmol), dibutyl dicarbonate (28.0 g, 128 mmol), THF (169 g), and 4-dimethylaminopyridine (99.8 mg, 0.82 mmol) were added to a 500 mL four-necked flask, and the reaction was carried out at 60 °C for 24 hours. After the reaction, the mixture was concentrated until the weight of the contents reached 117 g, and then isopropanol (156 g) was added to induce crystallization. The mixture was then cooled to 0 °C, stirred for 5 hours, and filtered. The filter cake was washed once with a mixed solution of isopropanol (39 g) and tetrahydrofuran (18 g). The obtained crystals were vacuum dried (50 °C) to obtain 26.5 g of crude DA-2-3. Then, under nitrogen atmosphere, crude DA-2-3 (26.5 g) and toluene (160 g) were added to a 500 mL four-necked flask. The solution was dissolved at 80 °C, and the mixture was kept at 45 °C. The precipitated impurities were removed by filtration. The solution was concentrated until the mass of the filtrate was 40.0 g. After standing at room temperature, the precipitated crystals were separated and dried under vacuum (50 °C) to obtain DA-2-3 (18.9 g, 36.5 mmol, yield 44.9%, yellow solid). [Chem. 18]

[0096] In a 500 mL four-necked flask under nitrogen atmosphere, DA-2-3 (17.9 g, 34.5 mmol), tetrahydrofuran (151 g), and carbon-supported palladium (5% Pd carbon powder (50% aqueous content) K type, NE Chemcat, 1.89 g) were added instead of hydrogen atmosphere, and the reaction was carried out at room temperature. After the reaction was completed, the carbon-supported palladium was removed by filtration, and the obtained filtrate was concentrated. The obtained wet product was dried under vacuum at 50 °C to obtain DA-2 (12.8 g, 27.9 mmol, yield 80.9%, amber solid). The 1H-NMR results shown below confirmed that this solid was DA-2. 1H-NMR (500MHz, DMSO-d6): δ (ppm) = 8.66 (t, 1H, J = 5.5Hz), 6.65 (d, 2H, J = 9.0Hz), 6.60 (d, 2H, J = 9.0Hz), 6.48 (dd, 4H , J=9.0Hz, 2.1Hz), 4.54 (d, 4H, J=7.0Hz), 3.85-3.75 (m, 6H,), 3.29 (q, 2H, J=7.0Hz), 1.87-1.81 (m, 4H), 1.44 (s, 9H)

[0097] [Polymer Synthesis] (Synthesis Example 1) DA-3 (0.541 g, 5.00 mmol), DA-1 (2.65 g, 5.00 mmol), and NMP (23.4 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 60 °C while supplying nitrogen to dissolve the polymer. After cooling to room temperature, CA-1 (2.15 g, 9.60 mmol) and NMP (15.8 g) were added, and the mixture was stirred at 40 °C for 24 hours to obtain a polyacrylic acid (PAA-1) solution with a solid content of 12% by mass. The Mn of this polyacrylic acid was 10,600, and the Mw was 31,900.

[0098] (Synthesis Example 2) DA-3 (0.541 g, 5.00 mmol), DA-2 (2.29 g, 5.00 mmol), and NMP (20.8 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature while supplying nitrogen to dissolve the substances. Then, CA-1 (2.16 g, 9.65 mmol) and NMP (15.9 g) were added, and the mixture was stirred at 40°C for 24 hours to obtain a polyacrylic acid (PAA-2) solution with a solid content of 12% by mass. The Mn of this polyacrylic acid was 14,400, and the Mw was 46,300.

[0099] (Synthesis Example 3) DA-3 (0.541 g, 5.00 mmol), DA-6 (1.71 g, 5.00 mmol), and NMP (16.5 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature while supplying nitrogen to dissolve the substances. Then, CA-1 (2.19 g, 9.78 mmol) and NMP (16.1 g) were added, and the mixture was stirred at 40°C for 24 hours to obtain a polyacrylic acid (PAA-3) solution with a solid content of 12% by mass. The Mn of this polyacrylic acid was 16,700, and the Mw was 52,800.

[0100] (Synthesis Example 4) DA-3 (0.541 g, 5.00 mmol), DA-7 (1.99 g, 5.00 mmol), and NMP (18.5 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature while supplying nitrogen to dissolve the substances. Then, CA-1 (2.16 g, 9.65 mmol) and NMP (15.9 g) were added, and the mixture was stirred at 40 °C for 24 hours to obtain a polyacrylic acid (PAA-4) solution with a solid content of 12% by mass. The Mn of this polyacrylic acid was 13,000, and the Mw was 37,800.

[0101] (Synthesis Example 5) DA-3 (0.541 g, 5.00 mmol), DA-8 (1.79 g, 5.00 mmol), and NMP (17.1 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature while supplying nitrogen to dissolve the substances. Then, CA-1 (2.15 g, 9.60 mmol) and NMP (15.8 g) were added, and the mixture was stirred at 40 °C for 24 hours to obtain a polyamide (PAA-5) solution with a solid content of 12% by mass. The Mn of this polyamide was 16,100, and the Mw was 52,300.

[0102] (Synthesis Example 6) DA-3 (0.324 g, 3.00 mmol), DA-4 (0.733 g, 3.00 mmol), DA-5 (0.641 g, 2.00 mmol), DA-1 (1.06 g, 2.00 mmol), and NMP (20.2 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 60 °C while supplying nitrogen gas until dissolved. After cooling to room temperature, CA-1 (2.15 g, 9.57 mmol) and NMP (15.7 g) were added, and the mixture was stirred at 40 °C for 24 hours to obtain a polyacrylic acid (PAA-6) solution with a solid content of 12% by mass. The Mn of this polyacrylic acid was 14,600, and the Mw was 37,500.

[0103] (Synthesis Example 7) DA-3 (0.324 g, 3.00 mmol), DA-4 (0.733 g, 3.00 mmol), DA-5 (0.641 g, 2.00 mmol), DA-2 (0.917 g, 2.00 mmol), and NMP (19.2 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature while supplying nitrogen gas until dissolved. Then, CA-1 (2.14 g, 9.53 mmol) and NMP (15.7 g) were added, and the mixture was stirred at 40 °C for 24 hours to obtain a polyacrylic acid (PAA-7) solution with a solid content concentration of 12% by mass. The Mn of this polyacrylic acid was 14,100, and the Mw was 36,500.

[0104] (Synthesis Example 8) DA-3 (0.324 g, 3.00 mmol), DA-4 (0.733 g, 3.00 mmol), DA-5 (0.641 g, 2.00 mmol), DA-6 (0.683 g, 2.00 mmol), and NMP (17.5 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature while supplying nitrogen to dissolve the substances. Then, CA-1 (2.16 g, 9.62 mmol) and NMP (15.8 g) were added, and the mixture was stirred at 40 °C for 24 hours to obtain a polyacrylic acid (PAA-8) solution with a solid content of 12% by mass. The Mn of this polyacrylic acid was 12,100, and the Mw was 32,400.

[0105] (Synthesis Example 9) DA-3 (0.324 g, 3.00 mmol), DA-4 (0.733 g, 3.00 mmol), DA-5 (0.641 g, 2.00 mmol), DA-7 (0.797 g, 2.00 mmol), and NMP (18.3 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature while supplying nitrogen to dissolve the substances. Then, CA-1 (2.14 g, 9.56 mmol) and NMP (15.7 g) were added, and the mixture was stirred at 40 °C for 24 hours to obtain a polyacrylic acid (PAA-9) solution with a solid content of 12% by mass. The Mn of this polyacrylic acid was 12,100, and the Mw was 32,300.

[0106] (Synthesis Example 10) DA-3 (0.324 g, 3.00 mmol), DA-4 (0.733 g, 3.00 mmol), DA-5 (0.641 g, 2.00 mmol), DA-8 (0.717 g, 2.00 mmol), and NMP (17.7 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature while supplying nitrogen to dissolve the substances. Then, CA-1 (2.13 g, 9.49 mmol) and NMP (15.6 g) were added, and the mixture was stirred at 40 °C for 24 hours to obtain a polyacrylic acid (PAA-10) solution with a solid content of 12% by mass. The Mn of this polyacrylic acid was 12,600, and the Mw was 32,900.

[0107] (Synthesis Example 11) DA-9 (1.59 g, 8.00 mmol), DA-10 (0.304 g, 2.00 mmol), and NMP (13.9 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature while supplying nitrogen to dissolve the substances. Then, CA-2 (2.74 g, 9.30 mmol) and NMP (20.1 g) were added, and the mixture was stirred at 70 °C for 12 hours to obtain a polyacrylic acid (PAA-11) solution with a solid content of 12% by mass. The Mn of this polyacrylic acid was 9,700, and the Mw was 21,800.

[0108] The specifications of the polyamide solution obtained by the above synthesis example are shown in Table 1. In Table 1, the values ​​in parentheses for the tetracarboxylic acid component and the diamine component represent the amount (in moles) of each tetracarboxylic acid component and each diamine component used relative to the total amount of diamine component used in each polymerization step, per 100 moles.

[0109] [Table 1]

[0110] [Preparation of liquid crystal alignment agent] (Example 1) NMP (14.0g) and BCS (6.00g) were added to a solution (10.0g) of polyacrylic acid (PAA-1) obtained in Synthesis Example 1 above, and the mixture was stirred at room temperature for 30 minutes to obtain liquid crystal alignment agent (AL-1).

[0111] (Example 2, Comparative Examples 1-3) The polyacrylic acid solution used was replaced with (PAA-2) to (PAA-5) and otherwise carried out in the same manner as in Example 1 to obtain liquid crystal alignment agents (AL-2), (AL-C1) to (AL-C3).

[0112] (Example 3) NMP (6.80g) and BCS (7.20g) were added to a solution (3.0g) of polyacrylic acid (PAA-6) obtained in Synthesis Example 6 and a solution (7.0g) of polyacrylic acid (PAA-11) obtained in Synthesis Example 11, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (AL-3).

[0113] (Example 4) NMP (6.80g) and BCS (7.20g) were added to a solution (4.0g) of polyacrylic acid (PAA-7) obtained in Synthesis Example 7 and a solution (6.0g) of polyacrylic acid (PAA-11) obtained in Synthesis Example 11, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (AL-4).

[0114] (Comparative Example 4) The polyacrylic acid solution used was replaced with (PAA-8) instead of (PAA-6), and the same procedure as in Example 3 was performed to obtain a liquid crystal alignment agent (AL-C4).

[0115] (Comparative Examples 5-6) The polyacrylic acid solution used was replaced with (PAA-9) to (PAA-10), except that it was carried out in the same manner as in Example 4, and liquid crystal alignment agents (AL-C5) to (AL-C6) were obtained.

[0116] The specifications of the liquid crystal alignment agents obtained in the above examples and comparative examples are shown in Table 2. In the table, the values ​​in parentheses for polyamide represent the amount (parts by mass) of each polymer relative to 100 parts by mass of the total polymer composition.

[0117] [Table 2]

[0118] [Fabrication of Liquid Crystal Cells] Using the liquid crystal alignment agent obtained above, liquid crystal cells were fabricated according to the following procedure. The liquid crystal alignment agent was filtered through a filter with a pore size of 1.0 μm and then coated onto a glass substrate (40 mm long × 30 mm wide × 0.7 mm thick) with an ITO electrode by spin coating. After drying on a hot plate at 80°C for 60 seconds, it was calcined in an infrared furnace at 230°C for 20 minutes to form a liquid crystal alignment film with a thickness of 100 nm. The coated surface was then irradiated with ultraviolet light of 200 mJ / cm², 300 mJ / cm², or 400 mJ / cm² with a wavelength of 254 nm and an extinction ratio of 26:1 through a polarizing plate to perform alignment treatment. The substrate was then calcined in an infrared furnace at 230°C for 30 minutes to obtain a substrate with a liquid crystal alignment film (first glass substrate). In addition to aligning the alignment direction perpendicular to the first glass substrate, a substrate with a liquid crystal alignment film (second glass substrate) was obtained as described above. The two substrates were grouped together. 4μm diameter bead spacers (manufactured by Nichibukai Chemicals, silk balls, SW-D1) were coated onto one of the liquid crystal alignment films. A sealant (manufactured by Mitsui Chemicals, XN-1500T) was printed around the liquid crystal injection port, and the other substrate was attached, ensuring the alignment direction facing the liquid crystal alignment film surface was 0°. The substrate was then heated at 150°C for 60 minutes to harden the sealant, creating a void cell. Liquid crystal MLC-3019 (manufactured by Merck) was injected into this void cell using a depressurized injection method, and the injection port was sealed to obtain a liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour for evaluation.

[0119] [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 circular retardation within the pixel plane was measured without applied voltage. The standard deviation σ was calculated as 3σ. For in-plane uniformity, a smaller 3σ value is considered better.

[0120] [In-plane uniformity of contrast ratio] The in-plane uniformity of contrast ratio was evaluated for the liquid crystal alignment films (single films) obtained from the liquid crystal alignment agents of Examples 1-2 and Comparative Examples 1-3, and the liquid crystal alignment films (mixed films) obtained from the liquid crystal alignment agents of Examples 3-4 and Comparative Examples 4-6. Regarding the evaluation criteria, a value of 3σ less than 1.65 was rated as "○", and a value of 1.65 or higher was rated as "×". The results are shown in Table 3 (single films) and Table 4 (mixed films).

[0121] [Table 3]

[0122] [Table 4]

[0123] [Evaluation of Layer Separability] In Examples 3-4 and Comparative Examples 4-6 (PAA-11) of the preparation examples without using the above-mentioned liquid crystal alignment agent, liquid crystal alignment agents (AL-3a) to (AL-4a) and (AL-C4a) to (AL-C6a) were prepared according to the same procedure, respectively. Then, using the liquid crystal alignment agents (AL-3a) to (AL-4a) and (AL-C4a) to (AL-C6a) obtained above, the ultraviolet irradiation dose was set to 300 mJ / cm2, and liquid crystal cells were fabricated according to the same procedure as above, and the in-plane uniformity of contrast was evaluated. (The value obtained from this evaluation will be referred to as 3σ (for a single film).) Furthermore, using the liquid crystal alignment agents (AL-3) to (AL-4) and (AL-C4) to (AL-C6) obtained in the above-described preparation example, liquid crystal cells were fabricated using ultraviolet irradiation at 300 mJ / cm², following the same procedure as described above, and the in-plane uniformity of contrast was evaluated. (The value obtained from this evaluation will be referred to as 3σ (for a mixed film).) The difference between 3σ (for a single film) and 3σ (for a mixed film) was set to Δ3σ. A value less than 0.60 was rated as "○", and a value greater than 0.60 was rated as "×". Layer separation performance was evaluated. The results are shown in Table 5. When layer separation performance is low, the value of 3σ (for a mixed film) is larger than that of 3σ (for a single film), and the value of Δ3σ increases. On the other hand, when layer separation performance is high, the value of Δ3σ decreases.

[0124] [Table 5]

[0125] As shown in Tables 3 and 4, the liquid crystal alignment film obtained from the liquid crystal alignment agent using a specific diamine (0) diamine component exhibits good in-plane uniformity of contrast. Furthermore, as shown in Table 5, high layer separation performance is observed when two or more polymers are used. [Industrial Applicability]

[0126] The liquid crystal alignment film obtained by the liquid crystal alignment agent of the present invention is widely used in liquid crystal display elements of various operating modes, and can also be used as, for example, liquid crystal alignment film for phase difference film, liquid crystal alignment film for scanning antenna, liquid crystal array antenna or liquid crystal alignment film for transmission and scattering type liquid crystal dimming element.

[0127] The liquid crystal display element of the present invention can be effectively applied to devices with various functions, such as LCD TVs, clocks, portable games, word processors, notebook computers, navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various screens, information displays, etc.

[0128] Furthermore, the entire contents of the specification, scope of application, drawings and abstract of Japanese Patent Application No. 2021-177006 filed on October 28, 2021, and the entire contents of the specification, scope of application, drawings and abstract of Japanese Patent Application No. 2021-189681 filed on November 22, 2021, are incorporated herein by reference, as disclosed in the specification of this invention.

Claims

1. A liquid crystal alignment agent, characterized in that it contains a polymer (P), wherein the polymer (P) is selected from at least one of the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (O) represented by the following formula (DA) and a polyimide of the polyimide precursor, wherein Z1 independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms, wherein the hydrogen atoms of the alkyl, alkenyl, or alkynyl group may also be substituted with monovalent groups, and any hydrogen atoms on the benzene ring bonded to the amino groups at both ends may also be substituted with monovalent groups. A represents a divalent organic group (a) of an alkyl group having 4 to 10 carbon atoms, and any carbon-carbon bond therein that meets either of the following conditions (1) and (2). In addition, in the following conditions (1) and (2), *1 is bonded to a carbon atom of the alkyl group, and the carbon-carbon bond is selected from the carbon-carbon bonds that form the main chain of the polymer (P). (1) "*1-N(Boc)-*1" is inserted between carbon-carbon bonds at positions 2 and above. (2) "*1-N(Boc)-C(=O)-N(R)-*1" is inserted between carbon-carbon bonds at positions 1 and above. R represents a hydrogen atom or a divalent organic group, and Boc represents a third butoxycarbonyl group.

2. The liquid crystal alignment agent as claimed in claim 1, wherein, In the above formula (DA), A is selected from any of the following: *-(CH2)n1-N(Boc)-(CH2)n1'-N(Boc)-(CH2)n1”-*, *-(CH2)n2-N(Boc)-C(=O)-N(R)-(CH2)n2'-*, *-(CH2)n3-N(Boc)-C(=O)-N(R)-(CH2)n3'-N(R)-C(=O)-N(Boc)-(CH2)n3”-*. n1, n1', n1”, n2, n2', n3, n3', and n3” independently represent integers greater than 1. The sum of n1, n1', and n1” is 4 to 10, the sum of n2 and n2' is 4 to 10, and the sum of n3, n3', and n3” is 4 to 10. R and Boc are defined as in Request 1. When there are multiple R, they are defined independently.

3. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The diamine (0) is any diamine selected from the group consisting of the following formulas (dA-1) to (dA-2), Z1 and formula (DA) are synonymous, n1, n1', n1”, n2 and n2' independently represent integers greater than 1, the sum of n1, n1' and n1” is 4 to 10, the sum of n2 and n2' is 4 to 10, any hydrogen atom on the benzene ring bonded by the amino groups at both ends can also be replaced by a monovalent group, and R and Boc are as defined in claim 1.

4. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The polymer (P) is a polymer having at least one repeating unit selected from the group consisting of repeating unit (p1) represented by the following formula (1) and amide-iminoized structural units of the repeating unit (p1), in formula (1), X1 represents a tetravalent organic group, Y1 is a divalent organic group that has removed two amino groups from the diamine (0) represented by the formula (DA), and R and Z each independently represent a hydrogen atom or a monovalent organic group.

5. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The polymer (P) is obtained by polycondensation of the diamine component with a tetracarboxylic acid component containing acyclic aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, or derivatives thereof.

6. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The amount of the diamine (0) used is more than 5 moles relative to the diamine component.

7. The liquid crystal alignment agent of claim 1 or 2 further comprises a polymer (B), which is selected from at least one of the group consisting of a polyimide precursor obtained by using a diamine component that does not contain the diamine (0) and a polyimide of a polyimide derivative of the polyimide precursor.

8. A liquid crystal alignment film obtained from a liquid crystal alignment agent as claimed in any one of claims 1 to 7.

9. A liquid crystal display element comprising a liquid crystal alignment film as claimed in claim 8.

10. 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 7 onto a substrate; Step (2): calcining the applied liquid crystal alignment agent to obtain a film; Step (3): performing alignment treatment on the film obtained in step (2).

11. A method for manufacturing a liquid crystal display element as claimed in claim 10, wherein, This alignment process is an optical alignment process.

12. A diamine, represented by the formulas (dA-1) to (dA-2), wherein Z1 independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms, wherein the hydrogen atoms of the alkyl, alkenyl, or alkynyl group may be substituted with a monovalent group, n1, n1', n1”, n2, and n2' independently represent an integer greater than 1, the sum of n1, n1', and n1” is 4 to 10, the sum of n2 and n2' is 4 to 10, Boc represents a third butoxycarbonyl group, and any hydrogen atom on the benzene ring bonded by the amino groups at both ends may be substituted with a monovalent group.

13. A polymer obtained from a diamine component containing the diamine of claim 12.

14. A polyimide precursor obtained by a polycondensation reaction of a diamine component containing the diamine of claim 12 and a tetracarboxylic acid component.

15. A polyimide of a polyimide precursor, the polyimide precursor being obtained by a polycondensation reaction of a diamine component containing a diamine as claimed in claim 12 and a tetracarboxylic acid component.

16. A polymer selected from at least one of the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (0) represented by the following formula (DA) and a polyimide of the polyimide precursor, wherein Z1 independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms, wherein the hydrogen atoms of the alkyl, alkenyl, or alkynyl group may be substituted with monovalent groups, and any hydrogen atoms on the benzene ring bonded to the amino groups at both ends may be substituted with monovalent groups, A represents a divalent organic group (a) of an alkyl group having 4 to 10 carbon atoms, wherein any carbon-carbon bond satisfies any of the following conditions (1) and (2), and in the following conditions (1) and (2), *1 is bonded to a carbon atom of the alkyl group, wherein the carbon-carbon bond is selected from the carbon-carbon bonds forming the main chain of the polymer (P). (1) "*1-N(Boc)-*1" is inserted between two or more carbon-carbon bonds. (2) "*1-N(Boc)-C(=O)-N(R)-*1" is inserted between one or more carbon-carbon bonds. R represents a hydrogen atom or a monovalent organic group, and Boc represents a third butoxycarbonyl group.

17. As in claim 12, the diamine, wherein, The equations (dA-1) to (dA-2) are DA-1 or DA-2.