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

Abstract

The present application can obtain a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film, which can obtain a liquid crystal alignment film having a high voltage holding ratio and a small amount of accumulated electric charges even when a negative liquid crystal is used, and which is excellent in printability. A liquid crystal alignment agent containing a diamine (A) represented by the following formula (D A ), and one or two or more polymers (P). The polymer (P) is selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic acid derivative component, and a polyimide which is an imidization product of the polyimide precursor, and a polyimide which substantially does not contain a diamine component of the diamine (A) represented by the following formula (D A ). Z-NH-Ar1-X1-(R1-L) n -R2-X2-Ar2-NH-Z (D A )

Description

Technical Field

[0001] The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film. Background Technology

[0002] Liquid crystal display (LCD) elements are widely used in applications ranging from small devices like 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 typically possess a liquid crystal alignment film, essential for controlling the alignment of the liquid crystal molecules. Polyamic acid and its derivatives (such as polyimide) are commonly used as materials for the liquid crystal alignment film.

[0003] For liquid crystal display elements requiring high display quality, Patent Document 1 discloses a composition for a liquid crystal alignment film, wherein the composition contains an aromatic diamine such as 1,5-bis(4-aminophenoxy)pentane. Furthermore, Patent Document 2 discloses a diamine formed by two aromatic groups linked to an alkylene ester chain via an ether bond, and discloses a liquid crystal alignment agent containing polyamic acid or a derivative thereof obtained by using the diamine as a raw material.

[0004] Furthermore, in liquid crystal display elements such as IPS and FFS, the use of negative liquid crystals has been studied to improve contrast (Patent Document 3).

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 06-194670 Patent Document 2: WO2022 / 220199 Patent Document 3: WO2016 / 152928 Summary of the Invention

[0006] The problem that the invention aims to solve Liquid crystal display elements typically include: a liquid crystal layer sandwiched between an element substrate and a color filter substrate; pixel electrodes and a common electrode that apply an electric field to the liquid crystal layer; a liquid crystal alignment film that controls the orientation of the liquid crystal molecules in the liquid crystal layer; and thin film transistors (TFTs) that convert electrical signals supplied to the pixel electrodes; etc.

[0007] In recent years, large-screen and high-definition liquid crystal display elements have become mainstream, leading to the development of specifications for display elements with increased pixel counts, such as 4K and 8K. The liquid crystal alignment film requires characteristics that ensure uniform film thickness even with surface variations on substrates containing TFTs, and demands liquid crystal alignment agents with superior printability compared to previous methods.

[0008] The inventors conducted research and found that when coating tests were performed using the liquid crystal alignment agent disclosed in Patent Document 2, unevenness (uneven film thickness) was easily generated on the coating surface.

[0009] Therefore, to suppress film thickness unevenness, attention is focused on liquid crystal alignment agents containing diamines. However, it is known that when negative liquid crystals are applied to liquid crystal display elements made using these alignment agents, display defects such as image burn-in (image burn-in of zones and lines), unevenness, or contamination are prone to occur. To suppress these display defects, liquid crystal alignment films with excellent voltage retention are required.

[0010] Furthermore, in liquid crystal display elements such as IPS and FFS types, static electricity tends to accumulate within the liquid crystal cell. In addition, the application of asymmetrical voltage generated by the driving mechanism can also cause charge accumulation within the cell. This accumulated charge can disrupt the alignment of the liquid crystal or affect the display in the form of image retention, significantly degrading the display quality of the liquid crystal display element. Therefore, the liquid crystal alignment film requires a low amount of accumulated charge.

[0011] Based on the above, the object of the present invention is to provide a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film. The liquid crystal alignment agent exhibits excellent printability and can produce a liquid crystal alignment film with high voltage retention even when using negative liquid crystals. Furthermore, the object of the present invention is to provide a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film, wherein the liquid crystal alignment agent can produce a liquid crystal alignment film with low charge accumulation.

[0012] Solution for solving the problem In order to solve the above-mentioned technical problems, the inventors conducted in-depth research and found that liquid crystal alignment agents containing specific polymers are effective in achieving the above-mentioned objectives, thus completing the present invention.

[0013] The present invention is based on the following content.

[0014] A liquid crystal alignment agent comprising the following formula (D A The diamine (A) and one or more polymers (P) shown in the figure.

[0015] Polymer (P): Selected for the use of tetracarboxylic acid derivative components and substantially free from the following formula (D) A The polymers in the group consisting of a polyimide precursor obtained by diamine (A) as shown in the figure and a polyimide as an imide derivative of the polyimide precursor.

[0016] Z-NH-Ar1-X1-(R1-L) n -R2-X2-Ar2-NH-Z (D A ) (Formula (D)) A In this diagram, Ar1 and Ar2 each independently represent any divalent aromatic group from a divalent benzene ring, a biphenyl structure, or a naphthalene ring, wherein any hydrogen atom of the aromatic group is optionally substituted with a monovalent group. X1 and X2 each independently represent a single bond, -O-, or *1-O-CO-. (*1 indicates a bond with Ar1 or Ar2.) R1 and R2 each independently represent a divalent hydrocarbon group, wherein a portion of the hydrogen atoms of the divalent hydrocarbon group is optionally substituted with a halogen atom, a methyl group, a trifluoromethyl group, or a hydroxyl group. In the presence of multiple R1s, the multiple R1s may optionally be the same or different from each other. L represents -O-, -C(=O)-, -O-C(=O)-, or -C(=O)-O-. In the presence of multiple Ls, the multiple Ls may optionally be the same or different from each other. At least one L represents -O-C(=O)- or -C(=O)-O-. n is an integer from 1 to 6. Z represents a hydrogen atom or a monovalent organic group. Multiple Zs may be either identical or different from each other. It should be noted that, in this specification, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc., can be listed as halogen atoms. * indicates a bond.

[0017] Invention Effects According to the present invention, a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film can be obtained. The liquid crystal alignment agent can produce a liquid crystal alignment film with high voltage retention rate and low charge accumulation even when using negative liquid crystal, and has excellent printability.

[0018] The mechanism by which the above-mentioned effects of the present invention are achieved may not be clear, but it is generally presumed as follows: First, it is believed that the excellent printability is achieved by adding diamine in a low molecular weight state. Furthermore, it is believed that the high voltage retention rate and low charge accumulation are achieved by adding diamine with a high resistivity, thus demonstrating the above-mentioned effects of the invention. Attached Figure Description

[0019] Figure 1 This is a schematic partial cross-sectional view showing an example of a transverse electric field liquid crystal display element of the present invention.

[0020] Figure 2 This is a schematic partial cross-sectional view showing another example of the transverse electric field liquid crystal display element of the present invention. Detailed Implementation

[0021] The liquid crystal alignment agent of the present invention contains the following formula (D A The diamine (A) shown in the figure (hereinafter also referred to as a specific diamine (A)), and one or more polymers (P); polymer (P): selected from those using tetracarboxylic acid derivative components and substantially free from the following formula (D A The polymer is composed of a polyimide precursor obtained by diamine (A) as shown in the figure and a polyimide as an imide derivative of the polyimide precursor.

[0022] Z-NH-Ar1-X1-(R1-L) n -R2-X2-Ar2-NH-Z (D A ) (Formula (D)) A In this diagram, Ar1 and Ar2 each independently represent any divalent aromatic group from a divalent benzene ring, a biphenyl structure, or a naphthalene ring, wherein any hydrogen atom of the aromatic group is optionally substituted with a monovalent group. X1 and X2 each independently represent a single bond, -O-, or *1-O-CO-. (*1 indicates a bond with Ar1 or Ar2.) R1 and R2 each independently represent a divalent hydrocarbon group, wherein a portion of the hydrogen atoms of the divalent hydrocarbon group is optionally substituted with a halogen atom, a methyl group, a trifluoromethyl group, or a hydroxyl group. In the presence of multiple R1s, the multiple R1s may optionally be the same or different from each other. L represents -O-, -C(=O)-, -O-C(=O)-, or -C(=O)-O-. In the presence of multiple Ls, the multiple Ls may optionally be the same or different from each other. At least one L represents -O-C(=O)- or -C(=O)-O-. n is an integer from 1 to 6. Z represents a hydrogen atom or a monovalent organic group. Multiple Zs may be either identical or different from each other. <Specific Diamine (A)> The liquid crystal alignment agent of the present invention contains a specific diamine (A).

[0023] The content of a specific diamine (A) contained in the liquid crystal alignment agent of the present invention is preferably 0.1 parts by mass or more and 30 parts by mass or less per 100 parts by mass relative to the total content of the polymer (P).

[0024] From the perspective of maintaining the applied voltage and suppressing the accumulation of charge, the content of the specific diamine (A) is more preferably 0.5 parts by mass or more, and even more preferably 1.0 parts by mass or more, relative to the total content of the polymer (P) of 100 parts by mass.

[0025] From the viewpoint of obtaining a uniform coating film, the content of a specific diamine (A) relative to the total content of the polymer (P) is more preferably 25 parts by mass or less, and even more preferably 10 parts by mass or less, out of a total of 100 parts by mass.

[0026] Furthermore, the concentration of the specific diamine (A) in the total amount of the liquid crystal alignment agent is preferably 41 ppm by mass or more, and more preferably 4.1 × 10⁻⁶. 3 Mass below ppm.

[0027] Furthermore, the concentration of the specific diamine (A) in the total amount of the liquid crystal alignment agent is preferably 2.1 × 10⁻⁶. 2 Mass concentration of ppm or higher, more preferably 4.1 × 10⁻⁶. 2 Mass above ppm.

[0028] In the above formula (D) A In this compound, R1 and R2 are each independently a divalent hydrocarbon group, such as linear or branched alkylene groups, -CH=CH-, phenylene or cyclohexylene, etc., but not limited to these.

[0029] From the viewpoint of obtaining high liquid crystal orientation, R1 and R2 are preferably hydrocarbon groups with 2 to 6 carbon atoms, more preferably alkylene groups with 2 to 4 carbon atoms, and even more preferably alkylene groups with 2 or 4 carbon atoms.

[0030] A portion of the hydrogen atom in the divalent hydrocarbon group can be replaced by a halogen atom, a methyl group, a trifluoromethyl group, or a hydroxyl group. A fluorine atom is preferred as the halogen atom replacing the hydrogen atom in the divalent hydrocarbon group. In the presence of multiple R1 groups, the multiple R1 groups can be the same or different from each other.

[0031] L represents -O-, -C(=O)-, -O-C(=O)-, or -C(=O)-O-. When multiple Ls exist, they can be the same or different from each other. At least one L represents -O-C(=O)- or -C(=O)-O-, preferably at least two Ls represent -O-C(=O)- or -C(=O)-O-. n is an integer from 1 to 6, preferably an integer from 1 to 4, more preferably an integer from 2 to 4, and even more preferably an integer of 2 or 4.

[0032] If we list the above formulas (D) A The group "*-(R1-L)" in the text. n A more preferred specific example of "-R2-*" is the following structure.

[0033] *-(CH2) p -O-C(=O)-(CH2) q -C(=O)-O-(CH2) r -*; *-(CH2) p -C(=O)-O-(CH2) q -O-C(=O)-(CH2) r -*; *-(CH2) n1 -O-C(=O)-(CH2) n2 -C(=O)-O-(CH2) n3 -O-C(=O)-(CH2) n4 -C(=O)-O-(CH2) n5 -*; *-(CH2) n1 -C(=O)-O-(CH2) n2 -O-C(=O)-(CH2) n3 -C(=O)-O-(CH2) n4 -O-C(=O)-(CH2) n5 -*.

[0034] In the structure described, p, q, and r are each an independent integer from 1 to 6.

[0035] n1 to n5 are each an independent integer from 1 to 6. Among them, the total number of carbon atoms in the divalent hydrocarbon groups when n1 to n5 is 20 or less.

[0036] * indicates a bond.

[0037] As a replacement for the above formula (D) A The monovalent groups of the hydrogen atoms in the divalent aromatic groups Ar1 and Ar2 in the following can be listed as: halogen atoms, alkyl groups with 1 to 10 carbon atoms, alkenyl groups with 2 to 10 carbon atoms, alkoxy groups with 1 to 10 carbon atoms, fluoroalkyl groups with 1 to 10 carbon atoms, fluoroalkenyl groups with 2 to 10 carbon atoms, fluoroalkoxy groups with 1 to 10 carbon atoms, carboxyl groups, hydroxyl groups, alkoxycarbonyl groups with 1 to 10 carbon atoms, cyano groups, nitro groups, etc. Among these, halogen atoms, alkyl groups with 1 to 5 carbon atoms, alkoxy groups with 1 to 5 carbon atoms, fluoroalkyl groups with 1 to 5 carbon atoms, or fluoroalkoxy groups with 1 to 5 carbon atoms are preferred.

[0038] Preferred examples of the divalent aromatic groups represented by Ar1 and Ar2 include: 1,4-phenylene, 1,3-phenylene, 2-methyl-1,4-phenylene, 2-ethyl-1,4-phenylene, 2-propyl-1,4-phenylene, 2-butyl-1,4-phenylene, 2-isopropyl-1,4-phenylene, 2-tert-butyl-1,4-phenylene, 2-methoxy-1,4-phenylene, 2-ethoxy-1,4-phenylene, and 2-propoxy-1,4-phenylene. 2-Butoxy-1,4-phenylene, 2-Fluoro-1,4-phenylene, 2,3-Dimethyl-1,4-phenylene, 2,6-Dimethyl-1,4-phenylene, 4-Methyl-1,3-phenylene, 5-Methyl-1,3-phenylene, 4-Fluoro-1,3-phenylene, 2,3,5,6-Tetramethyl-1,4-phenylene, 4,4'-Biphenylene, 2-Methyl-4,4'-Biphenylene, 2-Ethyl-4,4'-Biphenylene, 2-Propyl-4,4'- Biphenylene, 2-butyl-4,4'-biphenylene, 2-tert-butyl-4,4'-biphenylene, 2-methoxy-4,4'-biphenylene, 2-ethoxy-4,4'-biphenylene, 2-fluoro-4,4'-biphenylene, 3-methyl-4,4'-biphenylene, 3-ethyl-4,4'-biphenylene, 3-propyl-4,4'-biphenylene, 3-butyl-4,4'-biphenylene, 3-tert-butyl-4,4'-biphenylene, 3-methoxy-4,4'-biphenylene '-Biphenylene, 3-ethoxy-4,4'-biphenylene, 3-fluoro-4,4'-biphenylene, 2,2'-dimethyl-4,4'-biphenylene, 3,3'-dimethyl-4,4'-biphenylene, 3,3'-biphenylene, 5-methyl-3,3'-biphenylene, 5,5'-dimethyl-3,3'-biphenylene, 1,4-naphthylene, 1,5-naphthylene, 1,6-naphthylene, 1,7-naphthylene, 2,6-naphthylene, 2,7-naphthylene, etc.

[0039] As the above formula (D) A The Z-valent organic groups in ) can be listed as: monovalent hydrocarbon groups with 1 to 6 carbon atoms; the methylene group of the hydrocarbon group is surrounded by -O-, -S-, -CO-, -COO-, -COS-, -NR-. 3 -、-CO-NR 3 -, -Si(R) 3 )2-(where R 3A monovalent group A formed by substituting hydrogen atoms or monovalent hydrocarbon groups with 1 to 6 carbon atoms, such as -SO2-; a monovalent group formed by substituting at least one of the hydrogen atoms bonded to the carbon atoms of the above-mentioned monovalent hydrocarbon groups or monovalent group A with halogen atoms, hydroxyl groups, alkoxy groups, nitro groups, amino groups, mercapto groups, nitroso groups, alkylsilyl groups, alkoxysilyl groups, silanol groups, sulfinyl groups, phospho groups, carboxyl groups, cyano groups, sulfonyl groups, acyl groups, etc.; a monovalent group having a heterocyclic ring.

[0040] As the above formula (D) A The Z-valent organic group in the ) is preferably an alkyl group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, an alkynyl group with 2 to 6 carbon atoms, or a tert-butoxycarbonyl group, more preferably an alkyl group with 1 to 3 carbon atoms, and even more preferably a methyl group.

[0041] From the viewpoint of properly obtaining the effects of the present invention, each of Z is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group.

[0042] As the above formula (D) A A preferred example of ) can be listed as the following formula (d) A -1) ~ (d) A -10).

[0043] It should be noted that the following formula (d) A -1) ~ (d) A The hydrogen atoms on the benzene ring in (-10) can be replaced by monovalent substituents. As a preferred specific example of such substituents, substitutions of the above formula (D) can be listed. A The structures exemplified by the monovalent groups of hydrogen atoms in the Ar1 and Ar2 divalent aromatic groups in the Ar1 and Ar2 divalent aromatic groups are shown in the example.

[0044] p, q, r, and n1 to n5 are defined in the same way as above. <Polymer (P)> The polymer (P) contained in the liquid crystal alignment agent of the present invention is selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid derivative component containing a tetracarboxylic acid dianhydride and a diamine component that substantially does not contain a specific diamine (A) and a polyimide as an imide derivative of the polyimide precursor.

[0045] In this invention, "substantially not containing a specific diamine (A)" means that the content of the specific diamine (A) in the diamine component used to manufacture the polymer (P) is 5 parts by mass or less relative to 100 parts by mass of the total raw material compounds used to manufacture the polymer (P). Furthermore, from the viewpoint of appropriately obtaining the effects of the present invention, the content of the specific diamine (A) in the diamine component used to manufacture the polymer (P) is preferably 3 parts by mass or less, more preferably 1 part by mass or less, and even more preferably 0.5 parts by mass or less relative to 100 parts by mass of the total raw material compounds used to manufacture the polymer (P).

[0046] Polymer (P) may include, for example, polyimide precursors or polyimides that use a tetracarboxylic acid derivative containing a tetracarboxylic acid dianhydride and a diamine containing a diamine other than a specific diamine (A) (hereinafter also referred to as "other diamines"). Here, the polyimide precursor is a polymer such as polyamic acid or polyamic acid ester that can be imidized to obtain a polyimide. The polymer (P) contained in the liquid crystal alignment agent may be one or more polymers.

[0047] Polyamic acid (P'), the polyimide precursor of the aforementioned polymer (P), can be obtained by polymerization of a diamine component (preferably containing other diamines) that substantially does not contain the aforementioned specific diamine (A) with a tetracarboxylic acid component. The aforementioned other diamines may be used alone or in combination of two or more.

[0048] The amount of other diamines used relative to the total diamine content used in the manufacture of polymer (P) is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more. Furthermore, the amount of other diamines used relative to the total diamine content used in the manufacture of polymer (P) is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less.

[0049] Examples of other diamines are listed below, but they are not the only ones. These other diamines can be used alone or in combination of two or more.

[0050] 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 formula (d ALThe diamine (B) shown in the diagram (hereinafter also referred to as "specific diamine (B)" excluding the diamines included in specific diamine (A), 1,4-phenylene bis(4-aminobenzoate), 1,4-phenylene bis(3-aminobenzoate), 1,3-phenylene bis(4-aminobenzoate), 1,3-phenylene bis(3-aminobenzoate), bis(4-aminophenyl) terephthalate, bis(3-aminophenyl) terephthalate, bis(4-aminophenyl) isophthalate, bis(3-aminophenyl) isophthalate; 4,4'-diaminoazobenzene or diaminodi Diamines with photooriented groups, such as phenylacetylene; diamines with photopolymerizable groups at the ends, such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallyl aniline; diamines with free radical polymerization initiator functions, such as 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylacetone and 2-(4-(2-hydroxy-2-methylpropionyl)phenoxy)ethyl-3,5-diaminobenzoate; diamines with amide bonds, such as 4,4'-diaminobenzoylaniline; 1,3-bis(4-aminophenyl) Urea, 1,3-bis(4-aminobenzyl)urea, 1,3-bis(4-aminophenethyl)urea, and other diamines containing urea bonds; 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, -(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(3-amino-4-methylphenyl)propane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene; 2,6-diaminopyridine, the following formula (d nThe specific diamine (C) shown in the diagram (hereinafter also referred to as "specific diamine (C)"). This excludes the diamines included in specific diamine (A), 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, 4,4'-diaminodiphenylethane-3-carboxylic acid, 4,4'- Diamines with carboxyl groups, such as diaminobiphenyl-3,3'-dicarboxylic acid, 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, 3,3'-diaminobiphenyl-4,4'-dicarboxylic acid, 3,3'-diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid, 4,4'-diaminodiphenylethane-3,3'-dicarboxylic acid, and 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid; 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indane-5-amine, 1 -(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; diamines having the group "-N(D)-" (D represents a protecting group that is removed and substituted with a hydrogen atom by heating, preferably a carbamate protecting group, more preferably a tert-butoxycarbonyl) of the following formulas (5-1) to (5-8), cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanostane 3,5-diaminobenzoate, and 3... Diamines having a steroidal skeleton, such as 6-bis(4-aminobenzoyloxy)cholestane; diamines shown in formulas (V-1) to (V-2) below; diamines having a siloxane bond, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; m-phenylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and diamines formed by bonding two amino groups to any of the formulas (Y-1) to (Y-167) described in WO2018 / 117239. (Formula (d) AL In ), Ar1 and Ar 1’ Each independently represents a benzene ring, biphenyl structure, or naphthalene ring, wherein one or more hydrogen atoms on the benzene ring, biphenyl structure, or naphthalene ring are optionally substituted with monovalent groups. L1 and L 1’Each independently represents a single bond, -O-, -C(=O)-, or -O-C(=O)-. A represents a divalent organic group consisting of -CH2-, an alkylene group having 2 to 12 carbon atoms, or a group formed by inserting at least one of -O-, -C(=O)-O-, and -O-C(=O)- between the carbon-carbon bonds of the alkylene group. Any hydrogen atom in A may optionally be replaced by a halogen atom. Wherein, in formula (d AL L1 and L in ) 1’ In the case of -O-, A represents -CH2-, an alkylene group with 2 to 12 carbon atoms, or a divalent organic group formed by inserting -O- between the carbon-carbon bonds of such an alkylene group. One or more hydrogen atoms on the aforementioned benzene ring, biphenyl structure, or naphthalene ring are optionally replaced by a monovalent group. Examples of such monovalent groups include: halogen atoms, alkyl groups with 1 to 3 carbon atoms, alkenyl groups with 2 to 3 carbon atoms, alkoxy groups with 1 to 3 carbon atoms, fluoroalkyl groups with 1 to 3 carbon atoms, fluoroalkenyl groups with 2 to 3 carbon atoms, fluoroalkoxy groups with 1 to 3 carbon atoms, alkoxycarbonyl groups with 2 to 3 carbon atoms, cyano groups, nitro groups, etc. Z represents a hydrogen atom or a monovalent organic group. Multiple Zs may optionally be the same or different from each other. (Formula (d) n In this context, Y represents a divalent organic group having a structure consisting of a heterocycle selected from nitrogen-containing atoms and an aromatic ring having an amino group indicated by "*21-NR-*22" (where *21 and *22 represent bonds bonded to the carbon atom constituting the aromatic ring. This carbon atom does not form a ring with the nitrogen atom bonded to R. R represents a hydrogen atom or a monovalent organic group, which is bonded to the nitrogen atom via a carbon atom other than the carbonyl carbon). Z represents a hydrogen atom or a monovalent organic group. The plurality of Zs may optionally be the same as or different from each other. (Boc represents tert-butoxycarbonyl.) In the above equation (V-1), m and n are integers from 1 to 3, satisfying 1 ≤ m + n ≤ 4. j is an integer of 0 or 1. X 1 It represents - (CH2) a - (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. R 1 This refers to monovalent groups such as fluorine atoms, alkyl groups containing fluorine atoms with 1 to 10 carbon atoms, alkoxy groups containing fluorine atoms with 1 to 10 carbon atoms, alkyl groups with 1 to 10 carbon atoms, alkoxy groups with 1 to 10 carbon atoms, and alkoxyalkyl groups with 2 to 10 carbon atoms. The presence of two m, n, and X groups...1 R 1 In the case of each, they independently possess the above definitions. In the above equation (V-2), X 2 It represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-.

[0051] The specific diamine (B) mentioned above is preferably of the following formula (d AL -1) ~ (d) AL The diamines shown in -10), 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, 1,2-bis(6-amino-2-naphthoxy)ethane, 1,4-bis(6-amino-2-naphthoxy)butane, 1,2-bis(6-amino-2-naphthyl)ethane, or 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine. As the above formula (d) n The nitrogen-containing heterocycles in the ring include, for example: pyrrole ring, imidazole ring, pyrazole ring, triazole ring, pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, indole ring, benzimidazole ring, purine ring, quinoline ring, isoquinoline ring, naphthidine ring, quinoxaline ring, phthalazine ring, triazine ring, carbazole ring, acridine ring, piperidine ring, piperazine ring, pyrrolidine ring, hexamethyleneimine ring, etc. Among these, pyridine ring, pyrimidine ring, pyrazine ring, piperidine ring, piperazine ring, quinoline ring, carbazole ring, or acridine ring are preferred.

[0052] As the above formula (d) n The R in the form of a monovalent organic group can be, for example, alkyl groups such as methyl, ethyl, and propyl; alkenyl groups such as vinyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl and methylphenyl; and alkoxy groups (e.g., methoxy and ethoxy). R is preferably a hydrogen atom or a methyl group.

[0053] As the above formula (d) nSpecific examples of diamines shown in the figure include, for example: 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, and the following formula (d n The diamine shown in formula (z-1) or the diamine shown in formula (z-1) to (z-14). In formula (d) n In -1), m1 and m1' are each an independent integer from 1 to 2. n1 is an integer from 1 to 3. R1 has the same meaning as R in the amino group shown in "*21-NR-*22" above.

[0054] In the case of multiple R1 and m1', the multiple R1 and m1' can be the same or different.

[0055] As the above formula (d) n Preferred specific examples of the diamines shown in (-1) can be listed as the diamines shown in the following formulas (Dp-1) to (Dp-6). (Tetracarboxylic acid component of polymer (P)) In the manufacture of the above-mentioned polyamic acid (P'), the tetracarboxylic acid component that reacts with the diamine component can be not only tetracarboxylic dianhydride, but also derivatives of tetracarboxylic dianhydride such as tetracarboxylic acid, tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters, or tetracarboxylic acid dialkyl ester dihalides.

[0056] Examples of tetracarboxylic acid components used in the manufacture of the aforementioned polyamic acid (P') include, for example, acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, or their derivatives.

[0057] Here, the acyclic aliphatic tetracarboxylic dianhydride is obtained by intramolecular dehydration of the four carboxyl groups bonded to the chain hydrocarbon structure. It is not necessary for the structure to consist solely of a chain hydrocarbon; a portion of it may also have an alicyclic or aromatic ring structure.

[0058] Furthermore, alicyclic tetracarboxylic dianhydrides are obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to the alicyclic structure. None of these four carboxyl groups are bonded to an aromatic ring. Moreover, it is not necessary for the structure to consist solely of an alicyclic structure; it can also have a chain hydrocarbon structure or an aromatic ring structure in a portion thereof.

[0059] With regard to the above-mentioned alicyclic tetracarboxylic dianhydrides or their derivatives, more preferably, they comprise tetracarboxylic dianhydrides or their derivatives having at least one partial structure selected from the group consisting of cyclobutane rings, cyclopentane rings, and cyclohexane rings. In particular, it is even more preferable that they comprise tetracarboxylic dianhydrides or their derivatives having at least one structure selected from the group consisting of cyclobutane rings, cyclopentane rings, and cyclohexane rings.

[0060] Aromatic tetracarboxylic dianhydrides are obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to an aromatic ring.

[0061] In the case of aromatic tetracarboxylic acid derivatives, more preferably, they include tetracarboxylic dianhydrides having a benzene ring or derivatives thereof.

[0062] As a tetracarboxylic acid component that can be used to manufacture the above-mentioned polyamic acid (P'), it is preferable to include the following tetracarboxylic dianhydride or its derivatives (in this invention, they are also collectively referred to as "specific tetracarboxylic acid derivatives (A)").

[0063] Acyclic aliphatic tetracarboxylic anhydrides such as 1,2,3,4-butanetetracarboxylic anhydride; 1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-difluoro-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic anhydride, ... - Cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic acid dianhydride, 2,3,5-tricarboxylated cyclopentylacetic acid dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)tetrahydronaphthyl-1,2-dicarboxylic acid dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, bicyclo[2.2]. 2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclic [2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, 2,4,6,8-tetracarboxylic bicyclic [3.3.0]octane-2:4,6:8-dianhydride and other alicyclic tetracarboxylic dianhydrides; pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl sulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-perfluoroisopropylidene diphthalic acid Aromatic tetracarboxylic anhydrides such as dianhydrides, 3,3',4,4'-biphenyltetracarboxylic anhydride, 2,2',3,3'-biphenyltetracarboxylic anhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, ethylene glycol bis(triphenylene) anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 4,4'-carbonyldiphthalic anhydride, 4,4'-oxydi(1,4-phenylene)bis(phthalic acid) dianhydride, or 4,4'-methylenedi(1,4-phenylene)bis(phthalic acid) dianhydride; and tetracarboxylic anhydrides as described in Japanese Patent Application Publication No. 2010-97188.

[0064] More preferred examples of the aforementioned specific tetracarboxylic acid derivative (A) are 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, 1,2,3,4-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 dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)- 8-Methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxylic acid bicyclo[3.3.0]octane-2:4,6:8-dianhydride, pyromellitic acid dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride, 3,3',4,4'-biphenyl sulfone tetracarboxylic acid dianhydride, 1,4,5,8-naphthalene tetracarboxylic acid dianhydride, 2,3,6,7-naphthalene tetracarboxylic acid dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic acid dianhydride 3,3',4,4'-perfluoroisopropylidene phthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, 4,4'-carbonyl phthalic anhydride, 4,4'-oxobis(1,4-phenylene)bis(phthalic acid) dianhydride, 4,4'-methylenebis(1,4-phenylene)bis(phthalic acid) dianhydride or derivatives thereof.

[0065] The proportion of the aforementioned specific tetracarboxylic acid derivative (A) used relative to the total tetracarboxylic acid components used is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 50 mol% or more.

[0066] The liquid crystal alignment agent of the present invention may also be in the form of polymer (B) and / or polymer (C) comprising the following polymers. It should be noted that polymer (B) and polymer (C) are forms of polymer (P).

[0067] Polymer (B): At least one polymer selected from the group consisting of a polyimide precursor obtained using a diamine component containing a specific diamine (B) and a polyimide as an imide derivative of the polyimide precursor. B ).

[0068] Polymer (C): At least one polymer selected from the group consisting of a polyimide precursor obtained using a diamine component containing a specific diamine (C) and a polyimide as an imide derivative of the polyimide precursor. C ).

[0069] <Polymer (B)> Polymer (B) is a polymer (P) selected from the group consisting of a polyimide precursor obtained by using a diamine component containing a specific diamine (B) and a polyimide as an imide derivative of the polyimide precursor. B Polymer (B) may use one or more polymers (P). B In cases where a diamine other than a specific diamine (B) is included as a diamine component, the specific diamine (A) is not included.

[0070] Polymer (P) B For example, a polyimide precursor obtained using a diamine component containing the aforementioned specific diamine (B), or a polyimide that is an imide derivative of the polyimide precursor. Here, the polyimide precursor is a polymer such as polyamic acid or polyamic acid ester that can be imidized to obtain a polyimide.

[0071] As the above polymer (P) B The polyamic acid (P) precursor of polyimide B It can be obtained by polymerizing a diamine component containing the above-mentioned specific diamine (B) with a tetracarboxylic acid component. The above-mentioned specific diamine (B) can be used alone or in combination of two or more.

[0072] The amount of a specific diamine (B) used relative to the total diamine composition is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more.

[0073] Used in the manufacture of the above-mentioned polyamic acid (P B The diamine component of the diamine may also include diamines other than the specific diamine (B) (hereinafter also referred to as "other diamine 2"). When other diamine 2 is used in combination with the specific diamine (B) mentioned above, the amount of the specific diamine (B) relative to the diamine component is preferably 90 mol% or less, more preferably 80 mol% or less.

[0074] As a preferred specific example of other diamine 2, a diamine obtained by excluding a specific diamine (B) from the aforementioned other diamines can be listed. Other diamine 2 may be a diamine obtained by excluding a specific diamine (C).

[0075] <Polymer (C)> Polymer (C) is a polymer (P) selected from the group consisting of a polyimide precursor obtained by using a diamine component containing a specific diamine (C) and a polyimide as an imide derivative of the polyimide precursor. C Polymer (P) C One or more polymers may be used.

[0076] Where a diamine other than a specific diamine (C) is included as a diamine component, the specific diamine (A) is not included.

[0077] Polymer (P) C For example, a polyimide precursor obtained using a diamine component containing the aforementioned specific diamine (C), or a polyimide that is an imidized form of the polyimide precursor. Here, the polyimide precursor is a polymer such as polyamic acid or polyamic acid ester that can be imidized to obtain a polyimide.

[0078] As the above polymer (P) C The polyamic acid (P) precursor of polyimide C It can be obtained by polymerizing a diamine component containing the above-mentioned specific diamine (C) with a tetracarboxylic acid component. The above-mentioned specific diamine (C) can be used alone or in combination of two or more.

[0079] The amount of a specific diamine (C) used relative to the total diamine composition is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and particularly preferably 30 mol% or more.

[0080] Used in the manufacture of the above-mentioned polyamic acid (P C The diamine component of the diamine may also include diamines other than the specific diamine (C) (hereinafter also referred to as "other diamines 3"). When other diamines 3 are used in combination with the specific diamine (C) mentioned above, the amount of the specific diamine (C) relative to the diamine component is preferably 90 mol% or less, more preferably 80 mol% or less.

[0081] In cases where other diamines 3 are included as diamine components, a specific diamine (A) is not included.

[0082] As a preferred specific example of other diamines 3, diamines obtained by excluding a specific diamine (C) from the other diamines 1 described above can be listed.

[0083] The other diamine 3 preferably comprises at least one diamine selected from the group consisting of at least one group selected from the group consisting of a urea bond, an amide bond, a carboxyl group, and a hydroxyl group, and at least one diamine selected from the group consisting of a specific diamine (B). The diamine component may be used alone or in combination of two or more diamines.

[0084] (polymer (P) B ), polymer (P) C (tetracarboxylic acid component) In the manufacture of the above polyamic acid (P) B '), polyamic acid (P C In the case of '), the tetracarboxylic acid component that reacts with the diamine component can be not only tetracarboxylic dianhydride, but also derivatives of tetracarboxylic dianhydride such as tetracarboxylic acid, tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters or tetracarboxylic acid dialkyl ester dihalides.

[0085] It is used to manufacture polyamic acid (P B '), polyamic acid (P C Specific examples of the tetracarboxylic acid component of ') include, among preferred examples, polymers (P) A The examples provided are acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, or their derivatives.

[0086] More preferably, it is used to manufacture polyamic acid (P B '), polyamic acid (P C The tetracarboxylic acid component of the ') more preferably comprises a tetracarboxylic acid dianhydride or a derivative thereof having at least one partial structure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring and a cyclohexane ring.

[0087] Furthermore, the amount of tetracarboxylic acid derivatives having the aforementioned specific partial structure used relative to the amount used in the manufacture of polyamic acid (P B '), polyamic acid (P C The total tetracarboxylic acid content of the ') is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 50 mol% or more.

[0088] (Liquid crystal alignment agent) The liquid crystal alignment agent of the present invention is, for example, a polymer (P) and a polymer other than the polymer (P) used as needed, preferably a liquid composition formed by dispersing or dissolving it in a suitable solvent.

[0089] The total content of polymers in the liquid crystal alignment agent of the present invention can be appropriately varied according to the desired coating thickness. From the perspective of forming a uniform and defect-free coating, it is preferably 1% by mass or more; from the perspective of solution storage stability, it is preferably 10% by mass or less. A particularly preferred total polymer content is 2% to 8% by mass.

[0090] When the liquid crystal alignment agent of the present invention contains polymer (P), the total content of polymer (P) relative to the total content of polymers contained in the liquid crystal alignment agent is preferably 1 to 100% by mass, more preferably 10 to 100% by mass, and particularly preferably 20 to 100% by mass.

[0091] When the liquid crystal alignment agent of the present invention contains polymer (B) and polymer (C), the mass ratio of polymer (C) to the content of polymer (B) (content of polyimide precursor in polymer (C) / content of polyimide precursor in polymer (B)) is preferably 10 / 90 to 90 / 10, more preferably 20 / 80 to 90 / 10, and even more preferably 20 / 80 to 80 / 20.

[0092] 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 selected from the group consisting of polyimide precursors other than the above-mentioned polymer (P) and polyimides that are imide derivatives of the polyimide precursors; 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.

[0093] Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley), and GSM301 (manufactured by Gifu Shellac Manufacturing). Specific examples of poly(isobutylene-maleic anhydride) copolymers include ISOBAM-600 (manufactured by Kuraray). Specific examples of poly(vinyl ether-maleic anhydride) copolymers include Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland).

[0094] The other polymers mentioned above can be used alone, or in combination of two or more. The proportion of the other polymers relative to 100 parts by mass of the total polymers contained in the liquid crystal alignment agent is preferably 90 parts by mass or less, more preferably 10 to 90 parts by mass, and even more preferably 20 to 80 parts by mass.

[0095] (Manufacturing of polyamic acid) Polyamic acid is produced by reacting a diamine component with a tetracarboxylic acid component in an organic solvent. The preferred ratio of the tetracarboxylic acid component to the diamine component used in the polyamic acid production reaction is 0.5 to 2 equivalents relative to the amino group of the diamine component and the anhydride group of the tetracarboxylic acid component; more preferably, the ratio is 0.8 to 1.2 equivalents relative to the amino group of the diamine component and the anhydride group of the tetracarboxylic acid component. Similar to conventional polycondensation reactions, the closer the equivalent of the anhydride group of the tetracarboxylic acid component is to 1 equivalent, the larger the molecular weight of the resulting polyamic acid.

[0096] The preferred reaction temperature for manufacturing polyamic acid is -20 to 150°C, more preferably 0 to 100°C. Furthermore, the preferred reaction time is 0.1 to 24 hours, more preferably 0.5 to 12 hours. The manufacturing of polyamic acid can be carried out at any concentration, preferably 1 to 50% by mass, more preferably 5 to 30% by mass. Alternatively, the reaction can be carried out at a high concentration initially, followed by the addition of solvent.

[0097] Specific examples of the aforementioned organic solvents include: cyclohexanone, cyclopentanone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolinone. Furthermore, when the polymer has high solvent solubility, solvents such as methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, or diethylene glycol monoethyl ether can be used.

[0098] (Manufacturing of polyamic acid esters) Polyamates can be obtained, for example, by the following known methods: [I] reacting the polyamic acid obtained by the above method with an esterifying agent, [II] reacting a tetracarboxylic acid diester with a diamine, [III] reacting a tetracarboxylic acid diester dihalide with a diamine, etc.

[0099] (Manufacturing of polyimide) Regarding polyimides, they can be obtained by cyclizing (imidizing) the aforementioned polyimide precursors such as polyamic acid or polyamic ester. It should be noted that the imidization rate mentioned in this specification refers to the proportion of imide groups in the total amount of imide groups and carboxyl groups (or their derivatives) derived from tetracarboxylic dianhydride or its derivatives. The imidization rate does not necessarily have to be 100% and can be adjusted arbitrarily according to the application and purpose.

[0100] Methods for imidizing polyimide precursors include: thermal imidization by heating a solution of the polyimide precursor while keeping it as is, and catalytic imidization by adding a catalyst to a solution of the polyimide precursor.

[0101] The temperature for thermal imidization of the polyimide precursor in solution is preferably 100–400°C, more preferably 120–250°C, and preferably carried out while removing water generated by the imidization reaction from the system.

[0102] Catalytic imidization of polyimide precursors can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring at -20 to 250°C, preferably 0 to 180°C. The amount of basic catalyst is 0.5 to 30 moles of the amide group, preferably 2 to 20 moles, and the amount of acid anhydride is 1 to 50 moles of the amide group, preferably 3 to 30 moles. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, or trioctylamine, among which pyridine has moderate basicity for the reaction to proceed and is therefore preferred. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, or pyromellitic anhydride, among which acetic anhydride facilitates purification after the reaction and is therefore preferred. The imidization rate based on catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[0103] In recovering the generated polyimide precursor or polyimide from the reaction solution of the polyimide precursor or polyimide, the reaction solution can be simply precipitated by adding it to a solvent. Examples of solvents for precipitation include methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer precipitated in the solvent can be recovered by filtration and then dried at room temperature or under normal or reduced pressure, or by heating. Furthermore, repeating the process of redissolving the recovered polymer in an organic solvent and then reprecipitating it 2 to 10 times reduces impurities in the polymer. Examples of solvents used in this process include alcohols, ketones, or hydrocarbons; using three or more solvents selected from these sources further improves purification efficiency and is therefore preferred.

[0104] When manufacturing the polyimide precursor and polyimide of this invention, a suitable end-capping agent can also be used with a tetracarboxylic acid component containing tetracarboxylic dianhydride or its derivative and a diamine component containing the aforementioned diamine to manufacture an end-capped polymer. The end-capped polymer has the effect of increasing the film hardness of the oriented film obtained from the coating and improving the adhesion properties between the sealant and the oriented film.

[0105] Examples of polyimide precursors and ends of polyimides in this invention include: amino, carboxyl, anhydride, or groups derived from the capping agents described below. Amino, carboxyl, and anhydride groups can be obtained through conventional condensation reactions or by capping the ends with the following capping agents.

[0106] Examples of capping agents include: acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynyl phthalic anhydride, etc.; dicarbonate diester compounds such as ditert-butyl dicarbonate and diallyl dicarbonate; acryloyl chloride, methacryloyl... Chlorocarbonyl compounds such as chlorine and nicotinyl chloride; monoamine compounds such as aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; and isocyanates with unsaturated bonds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, or 2-acryloyloxyethyl isocyanate and 2-methacryloyloxyethyl isocyanate.

[0107] The proportion of the capping agent used relative to 100 moles of the total diamine components used is preferably 0.01 to 20 moles, more preferably 0.01 to 10 moles.

[0108] The weight-average molecular weight (Mw) of the polyimide precursor and polyimide, as determined by gel permeation chromatography (GPC) based on the conversion of polyethylene glycol / polyethylene oxide, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000, and even more preferably 10,000 to 50,000. Furthermore, the molecular weight distribution (Mw / Mn) shown by the ratio of Mw to the number-average molecular weight (Mn) of polyethylene glycol / polyethylene oxide as 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.

[0109] The organic solvent contained in the liquid crystal alignment agent of the present invention is not particularly limited as long as it uniformly dissolves the polymer (P). Examples include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllacticamide, N,N-dimethylpropionamide, tetramethylurea, N,N-diethylformamide, N,N-diethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N- Dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, N-n-propyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-n-butyl-2-pyrrolidone, N-tert-butyl-2-pyrrolidone, N-n-pentyl-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone (also collectively referred to as good solvents), etc. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, or γ-butyrolactone are preferred. The content of the good solvent is preferably 20 to 99% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass.

[0110] Furthermore, the organic solvent contained in the liquid crystal alignment agent is preferably a mixed solvent that, in addition to the solvents mentioned above, also incorporates a solvent that improves the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent (also known as a poor solvent). Specific examples of poor solvents are described below, but are not limited thereto. The content of the poor solvent is preferably 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. The type and content of the poor solvent are appropriately selected based on the coating apparatus, coating conditions, coating environment, etc., of the liquid crystal alignment agent.

[0111] Examples of unsuitable solvents include: diisopropyl ether, diisobutyl ether, diisobutylmethanol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxyethyl acetate, 1-methylpentyl acetate, 2-ethylethyl butyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy)-1- Propanol, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, cyclohexyl acetate, 4-methyl-2-pentyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone), (1S,5R)-6,8-dioxabicyclo[3.2.1]octane-4-one, etc.

[0112] 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.

[0113] Preferred combinations of good and bad solvents include: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-dimethyllactic acid and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone, ethyl 3-ethoxypropionate, and dipropylene glycol. Monomethyl ether; N-ethyl-2-pyrrolidone, ethyl 3-ethoxypropionate, and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, ethyl 3-ethoxypropionate, and diethylene glycol monopropyl ether; N-ethyl-2-pyrrolidone, ethyl 3-ethoxypropionate, and diethylene glycol monopropyl ether; N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate; N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether; N,N-dimethyl lactamide and ethylene glycol monobutyl ether; N,N-dimethyl lactamide and propylene glycol diacetate; N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, diethylene glycol monoethyl ether, and butyl cellosolve acetate; N-methyl-2-pyrrolidone, diethylene glycol monomethyl ether, and butyl cellosolve acetate Acetate; N,N-dimethyl lactamide and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl -2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol dimethyl ether; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutylmethanol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether;N-Methyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, diethylene glycol diethyl ether, and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and propylene glycol diacetate; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and diisobutyl ketone; N-ethyl-2-pyrrolidone, γ-butyrolactone, and diisobutyl ketone; N-ethyl-2-pyrrolidone, N,N-dimethyllactic acid, and diisobutyl ketone; N- Methyl-2-pyrrolidone, ethylene glycol monobutyl ether, and ethylene glycol monobutyl ether acetate; γ-butyrolactone, ethylene glycol monobutyl ether acetate, and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, ethylene glycol monobutyl ether acetate, and propylene glycol dimethyl ether; N-methyl-2-pyrrolidone, 4-methyl-2-pentyl acetate, and ethylene glycol monobutyl ether; N-ethyl-2-pyrrolidone, cyclohexyl acetate, and 4-hydroxy-4-methyl-2-pentanone; cyclohexanone and propylene glycol monomethyl ether; cyclopentanone and propylene glycol monomethyl ether; N-methyl-2-pyrrolidone, cyclohexanone, and propylene glycol monomethyl ether, etc.

[0114] (Liquid crystal alignment agent) In addition to the diamine (A), polymer (P), polymers other than polymer (P), and organic solvent described above, the liquid crystal alignment agent of the present invention may also contain other components (hereinafter also referred to as additive components). Examples of such additive components include: at least one crosslinking compound selected from the group consisting of a crosslinking compound having at least one substituent selected from ethylene oxide, oxadiazonyl, terminal isocyanate, oxazoline, cyclic carbonate, hydroxyl, and alkoxy groups; and crosslinking compounds having polymerizable unsaturated groups; functional silane compounds; metal chelates; curing accelerators; surfactants; antioxidants; sensitizers; preservatives; and compounds for adjusting the dielectric constant and resistance of the obtained liquid crystal alignment film.

[0115] Preferred specific examples of the aforementioned crosslinking compounds include: ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromonepentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, bisphenol A type epoxy resins such as EPIKOTE (registered trademark) 828 (manufactured by MITSUBISHI CHEMICAL), bisphenol F type epoxy resins such as EPIKOTE 807 (manufactured by MITSUBISHI CHEMICAL), hydrogenated bisphenol A type epoxy resins such as YX-8000 (manufactured by MITSUBISHI CHEMICAL), and YX6954BH30 (manufactured by MITSUBISHI CHEMICAL). Epoxy resins containing a biphenyl backbone, such as CHEMICAL (manufactured by CHEMICAL Corporation); phenol-formaldehyde varnish-type epoxy resins, such as EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.); (ortho-, meta-, and para-)cresol-formaldehyde varnish-type epoxy resins, such as EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.); triglycidyl isocyanurate, such as TEPIC (registered trademark) (manufactured by Nissan Chemical Co., Ltd.); CELLOXIDE (registered trademark) 2021P (Daicel Chemical Co., Ltd.). Compounds containing tertiary nitrogen atoms, such as alicyclic epoxy resins (manufactured by Industries, Inc.), N,N,N',N'-tetraglycidyl-m-phenylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane or N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, and tetra(glycidyloxymethyl)methane, etc.; compounds containing two or more ethylene oxides; compounds containing two or more oxobutanes as described in paragraphs 0170 to 0175 of WO2011 / 132751; CORONATE (registered trademark) AP stable M, CORONATE Compounds with capped isocyanate groups, such as 2503, 2515, 2507, 2513, 2555, MILLIONATE (registered trademark) MS-50 (and above, manufactured by TOSOH), TAKENATE (registered trademark) B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (and above, manufactured by Mitsui Chemicals); 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), 2,2'-bis(5-methyl-2-oxazoline), 1,2,4-tris(2-oxazoline-2)-benzene, and compounds with oxazoline groups, such as EPOCROS (registered trademark) (manufactured by Nippon Shokubai Co., Ltd.);Compounds containing cyclic carbonate groups as described in paragraphs 0025 to 0030 and 0032 of WO2011 / 155577; N,N,N',N'-tetratetra(2-hydroxyethyl)hexamethylenediamine, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane, etc. Compounds containing hydroxyl and alkoxy groups; compounds shown in the following descriptions: glycerol mono(meth)acrylate, glycerol di(meth)acrylate (a mixture of 1,2- and 1,3-methyl acrylates), glycerol tri(meth)acrylate, glycerol 1,3-diglyceryl alcohol di(meth)acrylate, pentaerythritol tri(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate, and hexaethylene glycol mono(meth)acrylate.

[0116] 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.

[0117] Examples of compounds used to adjust dielectric constant and resistance include monoamines such as 3-aminomethylpyridine, which have aromatic heterocyclic rings containing nitrogen atoms. The content of the monoamine with the aromatic heterocyclic ring containing nitrogen atoms is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, more preferably 0.1 to 20 parts by mass.

[0118] Preferred specific examples of the aforementioned functional silane compounds include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane. The silanes include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris(3-trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane. The content of the functional silane compound is preferably 0.1 to 30 parts by weight, more preferably 0.1 to 20 parts by weight, relative to 100 parts by weight of the polymer component contained in the liquid crystal alignment agent.

[0119] The concentration of solid components in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent in the total mass of the liquid crystal alignment agent) should be appropriately selected considering factors such as viscosity and volatility, and is preferably 1 to 10 by mass.

[0120] The particularly preferred range of solid component concentration varies depending on the method used to coat the liquid crystal alignment agent onto the substrate. For example, when using spin coating, the solid component concentration is particularly preferably 1.5 to 4.5% by mass. When using printing, the solid component concentration is particularly preferably 3 to 9% by mass, thereby setting the solution viscosity to 12 to 50 mPa·s. When using inkjet printing, the solid component concentration is particularly preferably 1 to 5% by mass, thereby setting the solution viscosity to 3 to 15 mPa·s. The temperature for preparing the polymer composition is preferably 10 to 50°C, more preferably 20 to 30°C.

[0121] (Liquid crystal alignment film and liquid crystal display element) The liquid crystal display element of the present invention includes 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 it can be applied to various operating modes such as TN type, STN type, vertical alignment type (including VA-MVA type, VA-PVA type, etc.), in-plane switching type (IPS type, FFS type), and optically compensated bending type (OCB type).

[0122] The liquid crystal display element of the present invention can be manufactured, for example, by 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).

[0123] <Process (1): The process of coating the liquid crystal alignment agent onto the substrate> Step (1) is the process of applying liquid crystal alignment agent onto the substrate. A specific example of step (1) is described below.

[0124] A liquid crystal alignment agent is applied to one side of a substrate having a patterned transparent conductive film using appropriate coating methods such as roll coating, spin coating, printing, or inkjet printing. Here, the substrate material is not particularly limited as long as it is highly transparent; it can also be used with glass, silicon nitride, or plastics such as acrylic resin or polycarbonate. Furthermore, in reflective liquid crystal display elements, if only one side of the substrate is used, an opaque material such as a silicon wafer can be used, and the electrodes can be made of light-reflecting materials such as aluminum. In the manufacture of IPS or FFS type liquid crystal display elements, a substrate having electrodes composed of a patterned comb-shaped transparent conductive film or metal film and a counter substrate without electrodes are used. The transparent conductive film can be formed using, for example, indium tin oxide (ITO), indium zinc oxide (IZO), or mixtures thereof, using known methods.

[0125] Methods for coating a liquid crystal alignment agent onto a substrate and forming a film include screen printing, offset printing, flexographic printing, inkjet printing, and spraying. Among these, inkjet printing is preferred.

[0126] <Process (2): The process of firing the coated liquid crystal alignment agent> Step (2) is a process of firing the liquid crystal alignment agent coated on the substrate to form a film. A specific example of step (2) is described below.

[0127] After the liquid crystal alignment agent is coated onto the substrate in step (1), the solvent can be evaporated using a heating unit such as a heating plate, a hot air circulating oven, or an IR (infrared) oven; or thermal imidization of polyamic acid can be performed. The drying and firing steps after coating the liquid crystal alignment agent can be performed at any temperature and for any time, and can be repeated multiple times. For example, the firing temperature for the liquid crystal alignment agent can be 40 to 180°C. From the viewpoint of shortening the process, it can be performed at 40 to 150°C. There is no particular limitation on the firing time, and examples include 1 to 10 minutes or 1 to 5 minutes. In the case of thermal imidization of polyamic acid, a firing step at, for example, 150 to 300°C or 150 to 250°C can be added after the above steps. There is no particular limitation on the firing time, and examples include 5 to 40 minutes or 5 to 30 minutes.

[0128] If the film thickness of the fired film is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, it is preferred to be 5 to 300 nm, and more preferably 10 to 200 nm.

[0129] <Step (3): The step of oriented treatment of the film obtained in step (2)> Step (3) is a step of aligning the film obtained in step (2) depending on the situation. That is, in horizontally aligned liquid crystal display elements such as IPS or FFS, the coating is subjected to an alignment capability treatment. On the other hand, in vertically aligned liquid crystal display elements such as VA or PSA, the formed coating can be used as a liquid crystal alignment film as is, or the coating can be subjected to an alignment capability treatment. As an alignment treatment method for liquid crystal alignment films, the rubbing treatment method and the photo-alignment treatment method can be listed. As a photo-alignment treatment method, the following method can be listed: irradiating the surface of the above-mentioned film with radiation polarized in a fixed direction, and, depending on the situation, preferably performing a heating treatment at a temperature of 150 to 250°C to impart liquid crystal alignment (also known as liquid crystal alignment capability). As radiation, ultraviolet light or visible light with a wavelength of 100 to 800 nm can be used. Among them, ultraviolet light with a wavelength of 100 to 400 nm is preferred, and ultraviolet light with a wavelength of 200 to 400 nm is more preferred.

[0130] The preferred radiation dose is 1–10,000 mJ / cm². 2 More preferably, it is 100–5000 mJ / cm³. 2 Furthermore, to improve liquid crystal alignment when irradiated with radiation, the substrate having the above-mentioned film can be irradiated while being heated at 50–250°C. The liquid crystal alignment film thus produced allows the liquid crystal molecules to be stably aligned in a fixed direction.

[0131] Furthermore, in the above methods, water or solvents can be used to contact the liquid crystal alignment film irradiated with polarized radiation; or the liquid crystal alignment film irradiated with radiation can be heated.

[0132] The solvent used in the above-mentioned contact treatment is not particularly limited as long as it dissolves the decomposition products generated by radiation exposure on the film. Specific examples include: water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, etc. One solvent may be used, or a combination of two or more may be employed.

[0133] The temperature for heat treatment of the radiation-irradiated coating is more preferably 50–300°C, and even more preferably 120–250°C. The heat treatment time is preferably set to 1–30 minutes.

[0134] <Process (4): Process of manufacturing LCD cell> Prepare two substrates with liquid crystal alignment films formed thereon as described above, and place a liquid crystal composition between the two substrates that are positioned opposite each other. Specifically, the following two methods can be listed.

[0135] In the first method, two substrates are first arranged opposite each other with their respective liquid crystal alignment films facing each other, separated by a gap (cell gap). Next, the peripheries of the two substrates are bonded together using a sealant. After injecting a liquid crystal composition into the cell gap defined by the substrate surfaces and the sealant and bringing it into contact with the film surface, the injection hole is sealed.

[0136] In addition, a second method is known as the ODF (One Drop Fill) method. For example, a UV-curable sealant is applied to a predetermined area on one of two substrates on which a liquid crystal alignment film has been formed. A liquid crystal composition is then dropped onto several predetermined points on the surface of the alignment film. The other substrate is then bonded together with the alignment films facing each other, and the liquid crystal composition is spread across the entire surface of the substrate, bringing it into contact with the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. Regardless of the method used, it is ideal to further heat the liquid crystal composition to a temperature at which it becomes an isotropic phase, and then slowly cool it to room temperature, thereby removing the flow alignment during liquid crystal filling.

[0137] It should be noted that when the coating has been rubbed, the two substrates are arranged at a specified angle to each other with the rubbing direction of each coating, for example, in an orthogonal or antiparallel manner.

[0138] As a sealant, for example, epoxy resin containing a curing agent and alumina spheres as spacers can be used. As for the liquid crystal composition, there are no particular limitations; examples include liquid crystal compositions containing at least one liquid crystal compound (liquid crystal molecule) and exhibiting a nematic phase (hereinafter also referred to as nematic liquid crystals), liquid crystal compositions exhibiting a smectic phase, or liquid crystal compositions exhibiting a cholesteric phase, with nematic liquid crystals being preferred. Furthermore, various liquid crystal compositions with positive or negative dielectric anisotropy can be used. It should be noted that, hereinafter, liquid crystal compositions with positive dielectric anisotropy are also referred to as positive liquid crystals, and liquid crystal compositions with negative dielectric anisotropy are also referred to as negative liquid crystals.

[0139] The liquid crystal composition described above may contain liquid crystal compounds having fluorine atoms, hydroxyl groups, amino groups, fluorine-containing groups (e.g., trifluoromethyl), cyano groups, alkyl groups, alkoxy groups, alkenyl groups, isothiocyanate groups, heterocyclic groups, cycloalkanes, cycloolefins, steroidal skeletons, benzene rings, or naphthalene rings. It may also contain compounds having two or more rigid sites (liquid crystal proto-skeletons) that exhibit liquid crystal properties (e.g., bimesogenic compounds formed by two rigid biphenyl or terphenyl structures linked by an alkyl group).

[0140] Furthermore, from the viewpoint of improving liquid crystal orientation, the above-mentioned liquid crystal composition may further contain additives. Examples of such additives include: photopolymerizable monomers such as compounds with polymerizable groups; optically active compounds (e.g., S-811 manufactured by Merck Co., Ltd.); antioxidants; ultraviolet absorbers; pigments; defoamers; polymerization initiators; or polymerization inhibitors, etc.

[0141] Examples of positive liquid crystal displays include: Merck's ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081.

[0142] Examples of negative liquid crystals include: MLC-6608, MLC-6609, MLC-6610, MLC-7026 or MLC-7026-100 manufactured by Merck, and NA-1559 manufactured by DIC.

[0143] In addition, as a liquid crystal containing compounds with polymerizable groups, Merck's MLC-3023 can be cited as an example.

[0144] The liquid crystal alignment agent of the present invention is also preferably used in a liquid crystal display element (PSA type liquid crystal display element) having a liquid crystal layer between a pair of substrates having electrodes, and manufactured by the following steps: disposing a liquid crystal composition containing a polymerizable compound that is polymerized by at least one of active energy rays and heat between a pair of substrates, applying a voltage between the electrodes, and polymerizing the polymerizable compound by at least one of irradiation by active energy rays and heat.

[0145] Furthermore, the liquid crystal alignment agent of the present invention is also preferably used in a liquid crystal display element (SC-PVA type liquid crystal display element) having a liquid crystal layer between a pair of substrates having electrodes, and manufactured by the following steps: disposing a liquid crystal alignment film containing polymeric groups polymerized by at least one of active energy rays and heat between the pair of substrates, and applying a voltage between the electrodes.

[0146] <Process (4-2): PSA type liquid crystal display element> The liquid crystal composition containing the polymerizable compound is injected or dropped, except as described in (4) above. Examples of polymerizable compounds include polymeric compounds having one or more polymerizable unsaturated groups such as acrylate groups or methacrylate groups within their molecules.

[0147] <Process (4-3): SC-PVA mode liquid crystal display element> Alternatively, a liquid crystal display element can be manufactured by performing the same process as described above (4), followed by an ultraviolet irradiation process described later. According to this method, similar to the manufacture of the PSA-type liquid crystal display element, a liquid crystal display element with excellent response speed under low light irradiation can be obtained. The compound having polymerizable groups can be a compound having one or more of the aforementioned polymeric unsaturated groups within its molecule, and its content relative to 100 parts by mass of the total polymer component is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass. Furthermore, the aforementioned polymerizable groups can also be present in the polymer used as a liquid crystal alignment agent; examples of such polymers include polymers obtained by reacting a diamine component containing a diamine terminally having the aforementioned photopolymerizable groups.

[0148] <Process (4-4): Process of irradiating with ultraviolet light> The liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates obtained in (4-2) or (4-3) above. The applied voltage can be, for example, DC or AC of 5-50V. Furthermore, the irradiation light can be, for example, ultraviolet light or visible light with wavelengths of 150-800nm, preferably ultraviolet light with wavelengths of 300-400nm. The light source can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. The irradiation dose is preferably 1000-200000 J / m². 2 More preferably, it is 1000 to 100000 J / m 2 .

[0149] Furthermore, a liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell as needed. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include: a polarizing plate made by clamping a polarizing film called an "H film" that absorbs iodine while stretching and oriented polyvinyl alcohol with a cellulose acetate protective film, or a polarizing plate made of the H film itself.

[0150] The IPS substrate, which is a comb electrode substrate used in IPS mode, has: a substrate; a plurality of linear electrodes formed on the substrate and configured in a comb shape; and a liquid crystal alignment film formed on the substrate to cover the linear electrodes.

[0151] It should be noted that the FFS substrate, which is used as a comb electrode substrate in FFS mode, has: a substrate; a surface electrode formed on the substrate; an insulating film formed on the surface electrode; a plurality of linear electrodes formed on the insulating film and arranged in a comb shape; and a liquid crystal alignment film formed on the insulating film to cover the linear electrodes.

[0152] Figure 1 This is a schematic partial cross-sectional view showing an example of a lateral electric field liquid crystal display element of the present invention, which is an example of an IPS mode liquid crystal display element.

[0153] exist Figure 1 In the lateral electric field liquid crystal display element 1 illustrated in the example, liquid crystal 3 is held between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2c and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 has: a substrate 2a; a plurality of linear electrodes 2b formed on the substrate 2a and arranged in a comb-like configuration; and a liquid crystal alignment film 2c formed on the substrate 2a to cover the linear electrodes 2b. The opposing substrate 4 has: a substrate 4b; and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2c is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4c is also, similarly, the liquid crystal alignment film of the present invention.

[0154] In this transverse electric field liquid crystal display element 1, when a voltage is applied to the linear electrode 2b, an electric field is generated between the linear electrodes 2b as shown by the electric field line L.

[0155] Figure 2 This is a schematic partial cross-sectional view showing another example of the transverse electric field liquid crystal display element of the present invention, which is an example of an FFS mode liquid crystal display element.

[0156] exist Figure 2 In the lateral electric field liquid crystal display element 1 illustrated in the example, liquid crystal 3 is sandwiched between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2h and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 has: a substrate 2d; a surface electrode 2e formed on the substrate 2d; an insulating film 2f formed on the surface electrode 2e; a plurality of linear electrodes 2g formed on the insulating film 2f and arranged in a comb-like configuration; and a liquid crystal alignment film 2h formed on the insulating film 2f to cover the linear electrodes 2g. The opposing substrate 4 has: a substrate 4b; and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2h is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4a is also, like the liquid crystal alignment film of the present invention.

[0157] In this transverse electric field liquid crystal display element 1, when a voltage is applied to the surface electrode 2e and the linear electrode 2g, an electric field is generated between the surface electrode 2e and the linear electrode 2g as shown by the electric field line L.

[0158] Example The present invention will be further described in detail below with reference to examples, but the invention is not limited to these examples. The abbreviations of the compounds used and the methods for determining their properties are described below.

[0159] (Organic solvent) NMP: N-methyl-2-pyrrolidone GBL: γ-Butyrolactone BCS: Butyl Solvent (Tetracarboxylic acid dianhydride) CA-1 to CA-6: These are compounds represented by the formulas (CA-1) to (CA-6) below. (Diamine) DA-1 to DA-7: Compounds represented by the formulas (DA-1) to (DA-7) below, respectively. (additive) AD-1 to AD-2: Compounds represented by the formulas (AD-1) to (AD-2) below, respectively. <Viscosity Measurement> The measurements were performed using a TVE-22H type E viscometer (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL and a conical rotor TE-1 (1°34', R24), at a temperature of 25°C.

[0160] <Determination of molecular weight> Using the ambient temperature GPC (gel permeation chromatography) apparatus described below and under the following conditions, the determination was carried out, and Mn and Mw were calculated using the polyethylene glycol / polyethylene oxide conversion value.

[0161] GPC device: GPC-101 (manufactured by RESONAC (formerly Showa Denko) Co., Ltd.) Chromatographic columns: GPC KD-803 and GPC KD-805 (manufactured by RESONAC (formerly Showa Denko) Co., Ltd.) in tandem. Column temperature: 50℃ Eluent: N,N-dimethylformamide (as additives, lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, anhydrous phosphoric acid (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L) Flow rate: 1.0 mL / min Standard samples used for calibration curve preparation: TSK standard polyethylene oxide (molecular weight; approx. 900,000, approx. 150,000, approx. 100,000 and approx. 30,000) (manufactured by TOSOH) and polyethylene glycol (molecular weight; approx. 12,000, approx. 4,000 and approx. 1,000) (manufactured by Polymer Laboratories).

[0162] [Synthesis of monomers] DA-7 is a novel compound not disclosed in the literature. The product in the monomer synthesis example 1 below was synthesized by... 1 Identification was performed using 1H-NMR analysis. The analytical conditions are as follows.

[0163] Device: BRUKER ADVANCE III - 500MHz Determination solvent: deuterated dimethyl sulfoxide (DMSO-d6) Reference material: Tetramethylsilane (TMS) (δ 0.0 ppm for 1 H) <Synthesis Example 1: Synthesis of DA-7> THF (600 g), 4-dimethylaminopyridine (DMAP, 16.6 g, 13.6 mmol), and succinic anhydride (34.1 g, 341 mmol) were added to 2-(4-nitrophenoxy)ethanol (50.0 g, 273 mmol) and stirred at 50 °C. 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl, 59.8 g, 312 mmol) and 1,4-butanediol (11.7 g, 130 mmol) were added to the resulting solution and stirred at room temperature (25 °C) for 3 hours. After the reaction was complete, water (1.5 kg) was added to precipitate crystals. The filtered solid was dried to obtain crude crystals. THF (300 g) was added to the crude crystals, and the mixture was heated and stirred at 65 °C. After cooling to room temperature, methanol (1.5 kg) was added to recrystallize the crystals. The crystals were filtered out and dried to obtain DA-7-1 (yield: 60.4 g, 97.2 mmol, 75%).

[0164] 1 H-NMR (500MHz) in DMSO-d6: 8.21 (d, J=9.2Hz, 4H), 7.17 (d, J=9.2Hz, 4H), 4.37 (q, 8H), 3.99 (s, 4H), 2.58 (m, 8H), 1.57 (m, 4H).

[0165] The obtained DA-7-1 (60.3 g, 97.2 mmol) was replaced with THF (1.2 kg) for nitrogen exchange, followed by the addition of carbon-supported palladium (5% Pd carbon powder (containing water), K type, manufactured by NECHEMCAT) (6.0 g), and another nitrogen exchange was performed. The mixture was then placed in a hydrogen-filled Tedra sampling bag and stirred at room temperature for 4 days. After the reaction was complete, the carbon-supported palladium was removed through a membrane filter, and the filtrate was completely concentrated to precipitate crude crystals. The crude crystals were washed by adding isopropanol (240 g) and stirring at room temperature. The crystals were filtered out and dried to obtain DA-7 (yield: 44.8 g, 79.9 mmol, 82%).

[0166] 1 H-NMR (500MHz) in DMSO-d6: 6.65 (d, J=8.9Hz, 4H), 6.50 (d, J=8.9Hz, 4H), 4.62 (s, 4H), 4.27 (m, 4H), 4.00 (m, 8H), 2.57 (m, 8H), 1.59 (m, 4H).

[0167] <Determination of Compound Concentration> Using the LC (liquid chromatography) apparatus described below and under the following conditions, the concentration of compounds in the sample was determined based on the calibration curve produced.

[0168] LC device: 1290 Infinity II (manufactured by Agilent Technologies) Chromatographic column: InertSustain C18 4.6×250mm, 5µm (manufactured by GL Science). Column temperature: 40℃ Mobile phase: A: Phosphate buffer (pH 6.8), B: Acetonitrile, A / B = 40 / 60 Detector: PDA (wavelength 270nm) Flow rate: 1.0 mL / min [Polymer Synthesis] <Synthesis example 1> DA-1 (2.29 g, 8.00 mmol) and NMP (16.8 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature while introducing nitrogen. Then, CA-1 (1.69 g, 7.54 mmol) and NMP (12.4 g) were added, and the mixture was stirred at 40 °C for 18 hours to obtain a 12% by mass solution of polyamic acid (A-1) (viscosity: 225 mPa·s). The polyamic acid had a Mn of 10382 and a Mw of 32874.

[0169] <Synthesis example 2> DA-2 (0.977 g, 4.00 mmol), DA-3 (0.797 g, 4.00 mmol), and NMP (10.1 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 adding nitrogen to dissolve the DA-2. Then, CA-2 (1.50 g, 6.00 mmol) and NMP (8.30 g) were added, and the mixture was stirred at 50 °C for 5 hours. After cooling to room temperature, CA-3 (0.494 g, 1.68 mmol) and NMP (2.80 g) were added, and the mixture was stirred at 70 °C for 18 hours, thus obtaining a 15% by mass solution of polyamic acid (A-2) (viscosity: 304 mPa·s). The Mn of this polyamic acid was 9284, and the Mw was 26834.

[0170] <Synthesis Example 3> DA-1 (3.72 g, 13.0 mmol) and NMP (37.3 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature while introducing nitrogen. Then, after cooling to room temperature, CA-4 (2.64 g, 12.1 mmol) and NMP (9.30 g) were added, and the mixture was stirred at 50 °C for 18 hours to obtain a solution of polyamic acid (A-3) with a solid content of 12% by mass.

[0171] <Synthesis example 4> DA-3 (5.58 g, 28.0 mmol), DA-4 (1.39 g, 7.01 mmol), and NMP (62.7 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature while adding nitrogen. Then, CA-5 (5.08 g, 25.9 mmol) and NMP (3.80 g) were added, and the mixture was stirred at room temperature for 2 hours. Then, CA-6 (2.10 g, 6.99 mmol) and NMP (13.7 g) were added, and the mixture was stirred at room temperature for 18 hours, thus obtaining a polyamic acid (A-4) solution with a solid content of 15% by mass.

[0172] <Synthesis example 5> DA-5 (1.46 g, 3.50 mmol), DA-1 (1.00 g, 3.50 mmol), and NMP (18.0 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 adding nitrogen to dissolve the substances. After cooling to room temperature, CA-1 (1.48 g, 6.58 mmol) and NMP (10.8 g) were added, and the mixture was stirred at 40 °C for 18 hours to obtain a 12% by mass solution of polyamic acid (A-5) (viscosity: 282 mPa·s). The Mn of this polyamic acid was 10704, and the Mw was 39144.

[0173] The types and amounts of the tetracarboxylic acid and diamine components used in the above synthetic examples 1 to 5 are shown in Table 1. It should be noted that the values ​​for the tetracarboxylic acid and diamine components in Table 1 represent the proportion (mole parts) of each compound relative to the total amount of diamine components used to synthesize each polyamic acid. [Preparation of liquid crystal alignment agent] <Example 1> A solution of polyamic acid (A-1) obtained in Synthesis Example 1 (A-1) (3.90 g), NMP (0.90 g), GBL (6.36 g), BCS (6.00 g), AD-1 (1% GBL solution, 0.78 g), AD-2 (10% NMP solution, 0.39 g), and DA-5 (0.04 g) obtained in Synthesis Example 2 were added to a solution of polyamic acid (A-2) obtained in Synthesis Example 2 (1.63 g). The mixture was stirred at room temperature for 2 hours to obtain the liquid crystal alignment agent (AL-1) of the present invention.

[0174] <Examples 2-5 and Comparative Examples 1-4> As shown in Table 2, the types and amounts of polymer solutions, solvents and additives used were changed. Otherwise, the same operation as in Example 1 was carried out, thereby obtaining the liquid crystal alignment agents (AL-2) to (AL-5) of Examples 2 to 5 of the present invention and the liquid crystal alignment agents (AL-C1) to (AL-C4) of Comparative Examples 1 to 4. In Table 2, the values ​​of polymer 1, polymer 2, additive 1, additive 2, and diamine represent the proportions (parts by mass) of each polymer solid component and additive relative to the total 100 parts by mass of the polymer component.

[0175] The results of measuring the content and concentration of diamine DA-5 contained in the liquid crystal alignment agents AL-1 to AL-2 of Examples 1 to 2, the liquid crystal alignment agent AL-C2 of Comparative Example 2, and the liquid crystal alignment agent AL-C4 of Comparative Example 4 are shown in Table 3.

[0176] DA-5 in Table 3 *1 This indicates the content (parts by mass) of DA-5 when the total polymer components are set to 100 parts by mass. It should be noted that the limit of quantitation for this determination is 9.3 × 10⁻⁶. －3 (parts by weight).

[0177] In addition, DA-5 *2 This indicates the concentration of DA-5 (mass ppm) in the total amount of liquid crystal alignment agent. It should be noted that the limit of quantitation for this determination is 3.8 ppm by mass. [Making of LCD Cells] <Fabrication of a liquid crystal cell for evaluating voltage retention> First, prepare a substrate with electrodes. The substrate is a 30mm × 40mm glass substrate with a thickness of 0.7mm. ITO electrodes with a film thickness of 35nm are formed on the substrate. The electrodes are made of a stripe pattern with a spacing of 40mm in length and 10mm in width.

[0178] Next, the liquid crystal alignment agent obtained above was filtered using a 1.0 μm pore size filter and then coated onto the prepared electrode substrate using a spin-coating method. After drying on a heating plate at 80°C for 2 minutes, it was fired in an infrared furnace at 230°C for 20 minutes to form a 60 nm thick coating, thus obtaining a substrate with a liquid crystal alignment film. The liquid crystal alignment film was then subjected to friction alignment using rayon cloth (Hyperflex, HY-5318) (roller diameter: 120 mm, roller speed: 1000 rpm, moving speed: 20 mm / sec, pressing length: 0.4 mm). Then, it was cleaned by ultrasonic irradiation in pure water for 1 minute, and after removing water droplets using a blower, it was dried at 80°C for 10 minutes to obtain the substrate with the liquid crystal alignment film. Two substrates with liquid crystal alignment films were prepared. On one substrate, spherical spacers with a particle size of 4 μm were dispersed on the surface of the liquid crystal alignment film, leaving a liquid crystal injection port. A sealant (Mitsui Chemicals XN-1500T) was printed around the port. The other substrate was then bonded together with the friction direction opposite and the film surfaces facing each other. A heat treatment at 150°C for 60 minutes was then performed to cure the sealant, creating a blank cell. Negative liquid crystal NA-1559 (DIC Corporation) was injected into the blank cell using a reduced-pressure injection method, and the injection port was sealed to obtain the liquid crystal cell. The resulting liquid crystal cell was then heated at 120°C for 1 hour and placed at 23°C overnight for voltage retention rate evaluation.

[0179] <Fabrication of FFS-driven LCD cell> A liquid crystal cell with an FFS mode liquid crystal display element was manufactured.

[0180] First, a substrate with electrodes is prepared. The substrate is a rectangular glass substrate measuring 30mm × 50mm with a thickness of 0.7mm. An ITO electrode with a full-surface pattern, constituting a common electrode, is formed on the substrate as the first layer. A SiN (silicon nitride) film, formed by CVD (chemical vapor deposition), is formed on the first common electrode as the second layer. The thickness of the second SiN film is 300nm, which serves as an interlayer insulating film. A comb-shaped pixel electrode, formed by patterning the ITO film, is disposed on the second SiN film as the third layer, forming two types of pixels: a first pixel and a second pixel. Each pixel has dimensions of 10mm in length and 5mm in width. This electrode-equipped substrate has a structure where the first common electrode and the third pixel electrode are insulated from each other by the second SiN film.

[0181] The third-layer pixel electrode has a comb-like shape formed by multiple electrode lines with a width of 3μm arranged in parallel at 6μm intervals, which are bent at an inner angle of 160° in the central part. A pixel is formed by multiple electrode lines, and has a first region and a second region with the line connecting the bent part as the boundary.

[0182] Next, the liquid crystal alignment agent obtained above was filtered using a filter with a pore size of 1.0 μm, and then coated onto the electrode substrate (hereinafter referred to as the electrode substrate) and a glass substrate with columnar spacers having a height of 4 μm and an ITO film formed on the back side (hereinafter referred to as the opposing substrate) by spin coating. After drying on a heating plate at 80°C for 2 minutes, it was fired in a hot air circulating oven at 230°C for 20 minutes to form a coating film with a thickness of 60 nm. The coating film was then subjected to friction alignment treatment using rayon cloth (manufactured by Hyperflex, HY-5318) (roller diameter: 120 mm, roller speed: 1000 rpm, moving speed: 20 mm / sec, pressing length: 0.4 mm). Then, it was cleaned by ultrasonic irradiation in pure water for 1 minute, and after removing water droplets using a blower, it was dried on a heating plate at 80°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. It should be noted that, regarding the liquid crystal alignment film formed on the aforementioned electrode substrate, the alignment process was performed such that the direction in which the inner angles of the pixel bends are equally divided is parallel to the alignment direction of the liquid crystal. Regarding the liquid crystal alignment film formed on the opposing substrate, the alignment process was performed such that the alignment direction of the liquid crystal on the electrode substrate is consistent with the alignment direction of the liquid crystal on the opposing substrate during the fabrication of the liquid crystal cell. Using the two substrates as a group, a sealant (Mitsui Chemicals XN-1500T) was printed onto the substrates using a dispensing machine. The other substrate was then bonded together with its respective liquid crystal alignment film aligned at 0° and facing each other. The bonded substrates were then pressed together and heated in a hot air circulating oven at 150°C for 60 minutes to cure the sealant, thus producing an empty cell. Negative liquid crystal NA-1559 (DIC Corporation) was injected into the empty cell using a depressurized injection method, and the injection port was sealed, thereby obtaining an FFS-driven liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour and placed at 23°C for one night before evaluation.

[0183] [Characteristics Evaluation of LCD Cells] The characteristics of the liquid crystal cell used for voltage retention evaluation and the FFS-driven liquid crystal cell produced above are evaluated as follows.

[0184] <Evaluation of Voltage Retention Rate after Backlight Tolerance Test> The voltage retention rate was evaluated using a liquid crystal cell with a surface temperature of 50°C and a high-brightness backlight (light source: LED, brightness: 30000 cd / m²). 2 The cells were placed under irradiation for 96 hours. Then, a voltage of 1V was applied to the liquid crystal cell at 60°C for 60μsec, and the voltage was measured after 167ms. The degree to which the voltage was maintained was calculated as the voltage retention rate. A higher voltage retention rate is better.

[0185] Furthermore, in Table 4 below, “-” in Comparative Example 4 indicates that the voltage retention rate was not measured.

[0186] [Evaluation of the amount of charge accumulated due to AC drive] The liquid crystal cell fabricated as described above is placed between two polarizing plates arranged orthogonally to each other. With the pixel electrode and the common electrode short-circuited to achieve the same potential, an LED backlight is first irradiated from below the two polarizing plates. The angle of the liquid crystal cell is adjusted to minimize the brightness of the transmitted light from the LED backlight, measured above the two polarizing plates. Next, while applying an AC voltage with a frequency of 60 Hz to the liquid crystal cell, the V-T curve (voltage-transmittance curve) is measured, and the AC voltage at which the relative transmittance reaches 23% is calculated as the driving voltage.

[0187] In the image retention evaluation, an AC voltage of 60 Hz with a relative transmittance of 100% was applied, driving the liquid crystal cell for 60 minutes. Then, an AC voltage with a relative transmittance of 23% was applied, and while scanning the DC voltage, the applied voltage that minimized display flicker was measured. The absolute value of this applied voltage that minimized display flicker was defined as the charge accumulation amount. The smaller the charge accumulation amount, the better.

[0188] It should be noted that the image retention evaluation according to the above method is performed under the temperature condition that the liquid crystal cell temperature is 45°C.

[0189] Furthermore, in Table 4 below, “-” in Comparative Examples 1 and 4 indicates the amount of charge accumulation that was not measured.

[0190] [Evaluation of Coating Properties] The liquid crystal alignment agent obtained above was spin-coated onto an ITO substrate measuring 100mm × 100mm with a thickness of 1.1mm. After drying on a heating plate at 80°C for 2 minutes, it was fired in a hot air circulating oven at 230°C for 20 minutes to obtain a substrate with a liquid crystal alignment film with a thickness of 60nm. When the substrate with the liquid crystal alignment film is observed with the naked eye, if the coating surface is a uniform surface without any unevenness, it is classified as "good"; if unevenness can be visually confirmed on the coating surface, it is classified as "bad".

[0191] Table 4 shows the evaluation results of voltage retention rate, charge accumulation amount and coatability of each liquid crystal alignment agent used in Examples 1 to 5 and Comparative Examples 1 to 4.

[0192] It should be noted that in Table 4, the values ​​in parentheses for polymer components and additive diamine represent the proportions (parts by mass) of each polymer solid component and additive, assuming the total content of polymer solid components is set to 100 parts by mass. As shown in Table 4, the liquid crystal alignment film obtained by adding a specific diamine as an additive has a significantly higher voltage retention rate and a significantly lower charge accumulation rate compared with the liquid crystal alignment film obtained by adding a specific diamine as an additive (comparison of Examples 1-4 with Comparative Example 2, and Comparison of Example 5 with Comparative Example 3).

[0193] On the other hand, when a diamine other than a specific diamine is added as an additive, the improvement in voltage retention is smaller compared to the case where a specific diamine is added (comparison of Example 1 and Comparative Example 1). Furthermore, the coatability of the liquid crystal alignment agent in which a specific diamine is introduced into the polymer deteriorates compared to the liquid crystal alignment agent in which a specific diamine is added as an additive (comparison of Example 1 and Comparative Example 4).

[0194] Industrial availability The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention is widely used in liquid crystal display elements of various operating modes. For example, it can also be used as a liquid crystal alignment film for phase retardation films; liquid crystal alignment films for scanning antennas and liquid crystal array antennas; or as a liquid crystal alignment film for transmission and scattering type liquid crystal dimming elements.

[0195] The liquid crystal display element of the present invention can be effectively applied to devices with various functions, such as LCD TVs, clocks, portable game consoles, word processors, laptops, car navigation systems, portable camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, information displays, etc.

[0196] Explanation of reference numerals in the attached figures 1: Lateral electric field liquid crystal display element; 2: Comb electrode substrate; 2a, 4b, 2d: Substrate; 2b, 2g: Linear electrode; 2c, 2h, 4a: Liquid crystal alignment film; 2e: Surface electrode; 2f: Insulating film; 3: Liquid crystal; 4: Opposite substrate; L: Electric field line.

[0197] It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2024-052127, filed on March 27, 2024, are incorporated herein as a disclosure of the specification of this invention.

Claims

1. A liquid crystal alignment agent comprising the following formula (D A The diamine A shown in the figure, and one or more polymers P, Polymer P: Selected from components using tetracarboxylic acid derivatives and substantially free of the following formula (D) A The polymers in the group consisting of a polyimide precursor obtained by diamine A as shown in the diagram and a polyimide as an imide derivative of the polyimide precursor; Z-NH-Ar1-X1-(R1-L) n -R2-X2-Ar2-NH-Z (D A ) Formula (D) A In the above, Ar1 and Ar2 each independently represent any divalent aromatic group in a divalent benzene ring, a biphenyl structure, or a naphthalene ring, wherein any hydrogen atom of the aromatic group is optionally replaced by a monovalent group; X1 and X2 each independently represent a single bond, -O- or *1-O-CO-, where *1-O-CO- represents a bond with Ar1 or Ar2; R1 and R2 are each independently a divalent hydrocarbon group, wherein a portion of the hydrogen atom of the divalent hydrocarbon group is optionally replaced by a halogen atom, methyl, trifluoromethyl or hydroxyl, and in the presence of a plurality of R1s, the plurality of R1s may optionally be the same as or different from each other. L represents -O-, -C(=O)-, -O-C(=O)-, or -C(=O)-O-. When multiple L's exist, they can be chosen to be the same or different from each other. At least one L represents -O-C (=O)- or -C (=O)-O-; n is an integer from 1 to 6; Z represents a hydrogen atom or a monovalent organic group, and multiple Zs may optionally be the same or different from each other.

2. The liquid crystal alignment agent according to claim 1, wherein, The formula (D) A The group "*-(R1-L)" in the text n "-R2-*" is selected from the following structures, *-(CH2) p -O-C(=O)-(CH2) q -C(=O)-O-(CH2) r -*; *-(CH2) p -C(=O)-O-(CH2) q -O-C(=O)-(CH2) r -*; *-(CH2) n1 -O-C(=O)-(CH2) n2 -C(=O)-O-(CH2) n3 -O-C(=O)-(CH2) n4 -C(=O)-O-(CH2) n5 -*; *-(CH2) n1 -C(=O)-O-(CH2) n2 -O-C(=O)-(CH2) n3 -C(=O)-O-(CH2) n4 -O-C(=O)-(CH2) n5 -*; In the structure described above, p, q, and r are each an independent integer from 1 to 6; n1 to n5 are each an independent integer from 1 to 6, wherein the total number of carbon atoms in the divalent hydrocarbon groups when n1 to n5 is 20 or less; * indicates a bond.

3. The liquid crystal alignment agent according to claim 1, wherein, The diamine A is selected from the following formula (d A -1) ~ (d) A At least one diamine in the group consisting of -10), The formula (d) A -1) ~ (d) A In (-10), the hydrogen atoms on the benzene ring are optionally replaced by monovalent substituents, where p, q, and r are each an integer from 1 to 6, and n1 to n5 are each an integer from 1 to 6, wherein the total number of carbon atoms of the divalent hydrocarbon groups in the case of n1 to n5 is 20 or less.

4. The liquid crystal alignment agent according to claim 1, wherein, The liquid crystal alignment agent contains polymer B and / or polymer C. Polymer B: Selected to use a polymer containing the following formula (d) AL The polymer P is composed of at least one polymer from the group consisting of a polyimide precursor obtained by diamine B as shown in the diagram and an imide derivative of the polyimide precursor. B Wherein, the diamine B does not contain the diamine contained in the diamine A; Where a diamine other than diamine B is included as a diamine component, diamine A is not included; furthermore, where a diamine other than diamine B is included as a diamine component and diamine C is included, the amount of diamine C used is less than 30 mol% relative to the total diamine component. Formula (d) AL In ), Ar1 and Ar 1’ Each of the following can independently represent a benzene ring, a biphenyl structure, or a naphthalene ring, wherein one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring are optionally substituted with monovalent groups; L1 and L 1’ Each of these groups independently represents a single bond, -O-, -C(=O)-, or -O-C(=O)-, and A represents -CH2-, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group formed by inserting at least one of -O-, -C(=O)-O-, and -O-C(=O)- between the carbon-carbon bonds of the alkylene group, wherein any hydrogen atom in A is optionally replaced by a halogen atom; Among them, in equation (d) AL L1 and L in ) 1’ In the case of -O-, A represents -CH2-, an alkylene group with 2 to 12 carbon atoms, or a divalent organic group formed by inserting -O- between the carbon-carbon bonds of the alkylene group; Z represents a hydrogen atom or a monovalent organic group, and multiple Zs may be the same or different from each other; Polymer C: Selected from those containing 30 mol% or more of the following formula (d) containing all diamine components. n At least one polymer P from the group consisting of a polyimide precursor obtained by diamine C as shown in the diagram and an imide derivative of the polyimide precursor. C , In cases where diamines other than diamine C are included as diamine components, diamine A is not present. Formula (d) n In the above, Y represents a divalent organic group having a structure consisting of at least one nitrogen-containing atom in the group consisting of a heterocycle selected from nitrogen-containing atoms and an aromatic ring consisting of an amino group represented by "*21-NR-*22", wherein *21 and *22 represent bonds bonded to carbon atoms constituting the aromatic ring, wherein the carbon atoms do not form a ring with the nitrogen atom bonded to R, and R represents a hydrogen atom or a monovalent organic group, wherein the monovalent organic group is bonded to the nitrogen atom through a carbon atom other than the carbonyl carbon; Z represents a hydrogen atom or a monovalent organic group, and multiple Zs may optionally be the same or different from each other.

5. The liquid crystal alignment agent according to claim 4, wherein, The liquid crystal alignment agent contains polymer B and polymer C.

6. The liquid crystal alignment agent according to claim 4, wherein, The polymer B 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.

7. The liquid crystal alignment agent according to claim 4, wherein, The polymer C is obtained by the polycondensation reaction of the diamine component with a tetracarboxylic acid component containing acyclic aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride or derivatives thereof.

8. The liquid crystal alignment agent according to claim 1, wherein, It further contains at least one additive component selected from crosslinking compounds, functional silane compounds, metal chelates, curing accelerators, surfactants, antioxidants, sensitizers, preservatives, and compounds used to adjust the dielectric constant and resistance of the obtained liquid crystal alignment film. The crosslinking compound is selected from at least one crosslinking compound having at least one substituent selected from ethylene oxide, oxetyl, terminal isocyanate, oxazoline, cyclic carbonate, hydroxyl and alkoxy, and crosslinking compounds having polymerizable unsaturated groups.

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

10. A liquid crystal display element comprising the liquid crystal alignment film as described in claim 9.

11. The liquid crystal display element according to claim 10, wherein, The liquid crystal display element is a horizontal electric field liquid crystal display element.

12. A method for manufacturing a liquid crystal display element, comprising the following steps 1 to 3, Step 1: The step of coating the liquid crystal alignment agent as described in any one of claims 1 to 8 onto the substrate; Step 2: A step of firing the coated liquid crystal alignment agent to obtain a film; Step 3: The step of oriented treatment of the film obtained in step 2.

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