TW201316099A - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display device - Google Patents

Abstract

A liquid crystal alignment agent having excellent printability is provided. The liquid crystal alignment agent includes (A) at least one polymer (A) selected from a group consisting of a polyamic acid and a polyimide obtained by dehydration and ring closure reactions of the polyamic acid, wherein the polyamic acid is obtained by reacting a tetracarboxylic dianhydride with a diamine including a diamine compound (a1) having at least one carboxyl group in the molecular; and (B) at least one solvent (B) selected from a group consisting of a 1, 3-dimethyl-2-imidazolidinone, a N-ethyl-2-pyrrolidone and a compound as shown in the following formula (1).

Description

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

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element, and more particularly to a liquid crystal alignment agent which is difficult to precipitate a polymer component and which is excellent in printability (especially long-time printability), and A liquid crystal alignment film and a liquid crystal display element produced by a liquid crystal alignment agent.

Previously, liquid crystal display elements were known to have a horizontal alignment type liquid crystal display such as a twisted nematic (TN) mode, an in-plane switching (IPS) mode, and a fringe field switching (FFS) mode. Element, or vertical alignment type liquid crystal display element such as Vertical Alignment (VA) mode. The liquid crystal display elements include a liquid crystal alignment film for aligning liquid crystal molecules. In view of various characteristics such as heat resistance, mechanical strength, and affinity with liquid crystal, polyphthalic acid or polyimine is generally used as a material of the liquid crystal alignment film.

Further, in recent years, the liquid crystal display element has been used not only in display terminals such as personal computers as in the prior art, but also in various applications such as display units such as liquid crystal televisions, car navigation systems, mobile phones, and smart phones. On the other hand, there are cases where the use of the liquid crystal display element is used under conditions that are more severe than before in terms of brightness, driving time, and the like. In view of such a background, in recent years, as a liquid crystal display element, display quality is further required to be high, and display quality is reduced even when continuous driving for a long period of time is performed. Liquid crystal alignment agent for liquid crystal display element (for example, refer to Patent Document 1 or Patent Document) 2).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-97188

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2010-156934

In order to improve the display quality of the liquid crystal display device, for example, it is considered that the polyimide imidization ratio of the polyimide film in the liquid crystal alignment film is improved to improve electrical characteristics, or to introduce a liquid crystal alignment component (pretilt component) into the polyimide. ), the alignment of the liquid crystal is good. However, when these operations are performed, the solubility of the polymer is liable to lower or the cohesiveness of the polymer is likely to increase, thereby causing uneven printing when the liquid crystal alignment agent is applied onto the substrate, or when printing is performed for a long time. When the polyimide is precipitated, the printability is lowered.

The present invention has been made in view of the above problems, and a main object thereof is to provide a liquid crystal alignment agent excellent in printability, and a liquid crystal alignment film and a liquid crystal display element produced by using the liquid crystal alignment agent.

The inventors of the present invention conducted intensive studies to achieve the problems of the prior art as described above, and as a result, found that a polymer obtained by a reaction using a specific diamine and a tetracarboxylic dianhydride is used as a polymer component of a liquid crystal alignment agent. Further, the present invention can be solved by dissolving the polymer in a specific solvent to prepare a liquid crystal alignment agent, thereby solving the above problems. Specifically, according to the present invention, the following liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element can be provided.

According to the present invention, there is provided a liquid crystal alignment agent comprising: A) at least one polymer selected from the group consisting of polyacrylamide and polypyridamine which is dehydrated and closed by the polyamic acid (A) The polyamic acid is obtained by reacting a tetracarboxylic dianhydride with a diamine containing a diamine compound (a1) having one or more carboxyl groups in the molecule; and B) is selected from the group consisting of 1,3-dimethyl-2 - at least one solvent (B) of the group consisting of imidazolidinone, N-ethyl-2-pyrrolidone and a compound represented by the following formula (1);

(In the formula (1), R ¹ and R ² each independently represent a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or a monovalent group containing -O- between carbon-carbon bonds of the hydrocarbon group, and R ¹ and R ² may be bonded to each other to form a cyclic structure; and R ³ is an alkyl group having 1 to 6 carbon atoms).

The liquid crystal alignment agent of the present invention contains the polymer (A) as a polymer component and contains the solvent (B) as a solvent, whereby the coating property on the substrate is good, and even on a substrate for a long period of time. In the case of printing, it is also difficult to cause precipitation of a polymer, and it is excellent in long-term printability.

In the present invention, in order to further suppress the precipitation of the polymer, the content of the solvent (B) is preferably 10% by weight or more based on the entire solvent. Thereby, the coatability on the substrate or the long-term printability can be further improved. Further, as the tetracarboxylic dianhydride in the above polymer (A), 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 2,4,6,8-tetracarboxybicyclo can be suitably used [3.3. 0] tetracarboxylic dianhydride of at least any one of octane-2:4,6:8-dianhydride.

In the present invention, another aspect is that the above polymer (A) is used. Further comprising 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indol-5-amine and 1-(4-aminophenyl)-2 A compound of at least any one of 3-dihydro-1,3,3-trimethyl-1H-indole-6-amine is synthesized as a diamine.

In the manufacturing process of the liquid crystal display element, there is a phenomenon in which the substrate is left in the original state and placed (resting) after the liquid crystal alignment film is formed due to mechanical failure or flow-through operation adjustment or the like. At this time, since the moisture in the air is adsorbed or absorbed on the liquid crystal alignment film, there is a possibility that the liquid crystal display element produced by using the substrate has a low electrical characteristic and causes display unevenness. In this aspect, in the present aspect, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indole-5-amine, 1- (4-Aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indole-6-amine is used in combination with a diamine compound (a1) as a polymer. By the diamine, the long-term printability is not impaired, and even when the substrate is placed in a state in which the liquid crystal alignment film is formed, the electrical characteristics of the liquid crystal display element can be favorably maintained (the standing resistance can be maintained). good).

The liquid crystal alignment agent of the present invention preferably further contains dipropylene glycol monomethyl ether as a solvent in addition to the above solvent (B). By using the above solvent (B) in combination with dipropylene glycol monomethyl ether, the long-term printability can be further improved.

Further, according to the present invention, a liquid crystal alignment film formed of the liquid crystal alignment agent described above and a liquid crystal display element including the liquid crystal alignment film can be provided. Since the liquid crystal alignment film of the present invention is formed by using the liquid crystal alignment agent described above, even when printing is performed for a long period of time, the polymer is hardly precipitated and the film quality is good. Further, when a liquid crystal display element is produced by using such a liquid crystal alignment film, printing defects can be reduced in the manufacturing process, and as a result, productivity can be improved.

The liquid crystal alignment agent of the present invention contains at least one selected from the group consisting of polylysine obtained by reacting tetracarboxylic dianhydride with a diamine and polyimine which is obtained by dehydration ring closure of the polyamic acid. A polymer which is soluble in a solvent. Hereinafter, the liquid crystal alignment agent of the present invention will be described in detail.

<polylysine> [tetracarboxylic dianhydride]

Examples of the tetracarboxylic dianhydride for synthesizing the polyamic acid in the present invention include aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride. Specific examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride and the like; and the alicyclic tetracarboxylic dianhydride may, for example, be 1, 2, or 3. 4-cyclobutane tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5- Dioxo-3-furanyl)-naphthoquinone [1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl)-naphthoquinone [1,2-c]furan-1,3-dione, 3-oxabicyclo[3.2.1]octane- 2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl 3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, 2,4,6, 8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, 4,9-dioxatricyclo[5.3.1.0 ^2,6 ]undecane-3,5,8 In the case of the aromatic tetracarboxylic dianhydride, for example, pyromellitic dianhydride, and the like, and the like, in addition to the above, the use of Japanese Patent Laid-Open Publication No. 2010-97188 can be used. The tetracarboxylic dianhydride described. In addition, the above-mentioned tetracarboxylic dianhydride may be used alone or in combination of two or more.

The tetracarboxylic dianhydride for synthesizing polyamic acid preferably contains an alicyclic tetracarboxylic dianhydride from the viewpoints of transparency and solubility in a solvent, and preferably contains an alicyclic tetracarboxylic dianhydride selected from 2 ,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene幷[1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo -3-furanyl)-naphthoquinone [1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6: At least one of the group consisting of 8-dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride preferably contains a 2,3,5-tricarboxyl ring in terms of good printability. At least any one of pentyl acetic acid dianhydride and 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride.

The above tetracarboxylic dianhydride comprises 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8- In the case of at least one of the dianhydrides, the total content of the tetracarboxylic dianhydrides used in the synthesis of the polyamic acid is preferably 10 mol% or more, and more preferably 20 Mol%~100 mol%.

[diamine]

As the diamine for synthesizing the poly-proline in the present invention, at least a diamine compound (a1) having one or more carboxyl groups in the molecule is used. By using such a compound (a1), the solubility of the polymer component (polyglycine or polyimine) contained in the liquid crystal alignment agent in a solvent can be improved. In particular, the solubility in a solvent containing the solvent (B) shown below is good, and the printability is suitably improved by combining with the solvent.

[Diamine compound (a1)]

The diamine compound (a1) is not limited as long as it has a carboxyl group, and may be any of an aliphatic diamine, an alicyclic diamine, an aromatic diamine, and a diamine organooxane. The diamine compound (a1) is preferably an aromatic diamine, and particularly preferably a compound having a carboxyl group bonded to an aromatic ring of the aromatic diamine.

The number of carboxyl groups in the molecule of the diamine compound (a1) is preferably from 1 to 4, and more preferably from 1 or 2.

The compound represented by the following formula (a1-1) or the compound represented by the following formula (a1-2) is mentioned, for example, as a preferable diamine compound (a1).

(wherein X is a single bond, an oxygen atom or an alkanediyl group having 1 to 3 carbon atoms, and m and n are each independently an integer of 1 or 2, and s and t are each independently an integer of 0 to 2. , s+t=2. The hydrogen atom bonded to the carbon atom of the benzene ring may also be substituted by an alkyl group having 1 to 5 carbon atoms)

Specifically, the diamine compound (a1) can be exemplified by the compound represented by the following formula (a1-1-1) to the formula (a1-1-3), and the following formula (a1-2-1) to the formula (a1). A1-2-5) Compounds and the like respectively indicated.

The ratio of the above diamine compound (a1) is preferably 5 mol% from the viewpoint of the total amount of the diamine used in the synthesis of polyglycolic acid from the viewpoint of improving the solubility of the polylysine in the solvent. The above is more preferably 10 mol% to 80 mol%, still more preferably 10 mol% to 50 mol%.

The diamine for synthesizing the above polyamic acid may be used singly as the above-mentioned diamine compound (a1) alone or in combination with the above diamine compound (a1).

Examples of the other diamine which can be used herein include an aliphatic diamine other than the above diamine compound (a1), an alicyclic diamine, an aromatic diamine, a diamine organic nonanethanthanene, and the like. Specific examples of the compounds include aliphatic 1,1-m-xylylenediamine, 1,3-propanediamine, butanediamine, pentanediamine, hexamethylenediamine, and the like; Examples of the amine include 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), 1,3-bis(aminomethyl)cyclohexane, and the like; aromatic diamine For example, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2'-dimethyl Base-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,7-diaminopurine, 4,4' -diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 9,9-bis(4-aminophenyl)anthracene, 2,2-double [4-(4-Aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(p-phenylene diisopropylidene Diphenylamine, 4,4'-(m-phenylene diisopropylidene) bisaniline, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminobenzene) Oxy)biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 3,6-diamino Carbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diamino Oxazole, N-phenyl-3,6-diaminocarbazole, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)- N,N'-dimethylbenzidine, 1,4-bis-(4-aminophenyl)-peripher , 1-(4-Aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indole-5-amine, 1-(4-aminophenyl)-2, 3-Dihydro-1,3,3-trimethyl-1H-indol-6-amine, cholestyloxy-3,5-diaminobenzene, cholestyloxy-3,5- Diaminobenzene, cholestyloxy-2,4-diaminobenzene, cholestyloxy-2,4-diaminobenzene, 3,5-diaminobenzoic acid cholesteryl Ester, cholesteryl 3,5-diaminobenzoic acid, lanosteryl 3,5-diaminobenzoic acid, 3,6-bis(4-aminobenzylideneoxy) cholesteric Alkane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzylideneoxy)cyclohexyl-3,5-diaminobenzoic acid Ester, 4-(4'-trifluoromethylbenzylideneoxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl) Phenyl)-4-butylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-heptylcyclohexane, 1,1-double (4 -((Aminophenoxy)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-(4) -heptylcyclohexyl)cyclohexane, 2,4-diamino-N,N-diallylaniline, 4-aminobenzylamine, 3-aminobenzylamine, and the following formula (A) -1) represented by the combination Things, etc.:

(wherein, X ^I and X ^II are each a single bond, -O-, -COO- or -OCO-, respectively, R ^I is an alkanediyl group having a carbon number of 1 to 3, a is 0 or 1, and b is 0~ An integer of 2, c is an integer of 1 to 20, and n is 0 or 1. wherein a and b are not 0) at the same time; and the diamine organooxane may, for example, be a 1,3-bis(3-amino group) Further, a diamine described in JP-A-2010-97188 can be used as the propyl)-tetramethyldioxane.

The divalent group represented by "-X ^I -(R ^I -X ^II ) _n -" in the above formula (A-1) is preferably an alkanediyl group having a carbon number of 1 to 3, ^* -O-, ^* - COO- or ^* -OC ₂ H ₄ -O- (wherein the bond with " ^* " is bonded to the diaminophenyl group). Specific examples of the radical "-C _c H _2c+1 " include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-decyl, and Mercapto, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl , n-icosyl and the like. The two amine groups in the diaminophenyl group are preferably located at the 2,4-position or the 3,5-position relative to the radical "X ^I ".

Specific examples of the compound represented by the above formula (A-1) include, for example, compounds represented by the following formulas (A-1-1) to (A-1-3).

When synthesizing the above polyamic acid, it is preferred to further comprise 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indole-5-amine and 1 A diamine of at least one of -(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indole-6-amine as another diamine. By using these diamines together with the compound (a1), the standing tolerance can be improved. The content of the diamine is preferably 5 mol% or more, and more preferably 10 mol% to 50 mol%, based on the total amount of the diamine used.

Further, in the case of synthesizing polylysine contained in the liquid crystal alignment agent for vertical alignment type, in order to impart good vertical alignment, it is preferred to use a diamine having a pretilt component as the other diamine. Specifically, examples of such a diamine having a pretilt component include dodecyloxy-2,4-diaminobenzene, tetradecyloxy-2,4-diaminobenzene, and pentadecyloxy. Benzyl-2,4-diaminobenzene, hexadecyloxy-2,4-diaminobenzene, octadecyloxy-2,4-diaminobenzene, dodecyloxy-2,5 -diaminobenzene, tetradecyloxy-2,5-diaminobenzene, pentadecyloxy-2,5-diaminobenzene, cetyloxy-2,5-diaminobenzene , octadecyloxy-2,5-diaminobenzene, cholestyloxy-3,5-diaminobenzene, cholestyloxy-3,5-diaminobenzene, cholesteric Alkenyloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, 3,5-diamine Wool alkyl benzoate, 3,6-bis(4-aminobenzamide Oxy)cholinane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzylideneoxy)cyclohexyl-3,5-di Aminobenzoate, 4-(4'-trifluoromethylbenzyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((amino) Phenyl)methyl)phenyl)-4-butylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-heptylcyclohexane, 1, 1-bis(4-((aminophenoxy)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)) 4-(4-heptylcyclohexyl)cyclohexane, a diamine represented by the above formula (A-1), and the like. In addition, the diamine having a pre-tilt component may be used alone or in combination of two or more.

The total amount of the diamine having a pretilt component is preferably 5 mol% or more, and more preferably 10 mol% or more, based on all the diamines.

The diamine used in the synthesis of the poly-proline in the present invention preferably contains 30 mol% or more of an aromatic diamine (a diamine whose amine group is bonded to an aromatic ring) with respect to all diamines. It is preferably contained in an amount of 50 mol% or more, particularly preferably 80 mol% or more.

[Molecular weight regulator]

In the case of synthesizing polyamic acid, a terminal-modified polymer may be synthesized by using an appropriate molecular weight modifier together with the tetracarboxylic dianhydride and the diamine as described above. By forming the terminal-modified polymer, the coating property (printability) of the liquid crystal alignment agent can be further improved without impairing the effects of the present invention.

Examples of the molecular weight modifier include an acid monoanhydride, a monoamine compound, and a monoisocyanate compound. Specific examples of the compounds include, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride, and the like. N-hexadecyl succinic anhydride; Examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; and examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate. .

The use ratio of the molecular weight modifier is preferably 20 parts by weight or less, and more preferably 10 parts by weight or less, based on 100 parts by weight of the total of the tetracarboxylic dianhydride and the diamine to be used.

<Synthesis of polylysine>

The ratio of the tetracarboxylic dianhydride to the diamine to be used in the synthesis reaction of the polyaminic acid of the present invention is preferably 0.2 equivalents per equivalent of the amine group of the diamine. The ratio of 2 equivalents is more preferably a ratio of 0.3 equivalents to 1.2 equivalents.

The synthesis reaction of polylysine is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20 ° C to 150 ° C, and more preferably 0 ° C to 100 ° C. Further, the reaction time is preferably from 0.1 to 24 hours, more preferably from 0.5 to 12 hours.

Here, examples of the organic solvent include an aprotic polar solvent, a phenol and a derivative thereof, an alcohol, a ketone, an ester, an ether, a halogenated hydrocarbon, a hydrocarbon, and the like.

Specific examples of the organic solvent include, for example, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and N-ethyl-2-pyrrolidone. N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl hydrazine, γ-butyrolactone, tetramethylurea, hexamethylphosphonium triamine, the following formula (1) the compound or the like represented; examples of the phenol derivative include m-cresol, xylenol, halogenated phenol, and the like; Examples of the above-mentioned alcohol include methanol, ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, and ethylene glycol monomethyl ether; and examples of the above ketone include acetone. And methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; examples of the above esters include ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, and B. Ethyl oxypropionate, diethyl oxalate, diethyl malonate, etc.; examples of the ether include diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, and ethylene glycol isopropoxide. Ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol Monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, etc.; for the above halogenated hydrocarbon, for example, dichloromethane, 1,2-dichloroethane, 1, 4 - dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, etc.; examples of the above hydrocarbons include hexane, heptane, octane, benzene, toluene, xylene, isoamyl propionate, and the like. Isoamyl, diisoamyl ether and the like.

Among the organic solvents, it is preferred to use one or more selected from the group consisting of an aprotic polar solvent and a phenol and a derivative thereof (the first group of organic solvents), or an organic solvent selected from the first group. One or more kinds of a mixture of one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons (the second group of organic solvents). In the latter case, the use ratio of the organic solvent of the second group is preferably 50% by weight or less, and more preferably 40%, based on the total amount of the organic solvent of the first group and the organic solvent of the second group. The weight% or less is more preferably 30% by weight or less.

The amount (a) of the organic solvent to be used is preferably such an amount that the total amount of the tetracarboxylic dianhydride and the diamine (b) is from 0.1% by weight to 50% by weight based on the total amount of the reaction solution (a+b). The amount of %.

A reaction solution obtained by dissolving polylysine was obtained as described above. The reaction solution may be directly supplied to the liquid crystal alignment agent, or may be prepared by isolating the polylysine contained in the reaction solution to the liquid crystal alignment agent, or purifying the isolated polyamic acid to the liquid crystal. Modulation of the alignment agent. When polylysine is subjected to dehydration ring closure to form a polyimine, the reaction solution may be directly supplied to a dehydration ring-closure reaction, or the polylysine contained in the reaction solution may be isolated and dehydrated. The ring closure reaction, or the isolated polylysine is purified and supplied to the dehydration ring closure reaction. The isolation and purification of polylysine can be carried out in accordance with a known method.

<Synthesis of Polyimine and Polyimine>

The polyimine contained in the liquid crystal alignment agent of the present invention can be obtained by subjecting the polylysine synthesized as described above to dehydration ring closure to imidize the ruthenium.

The polyimine may be a complete hydrazine imide formed by dehydration ring closure of the proline structure of the polyglycolic acid as a precursor thereof, or may be only a part of the guanamine structure, dehydration ring closure, guanamine A partial quinone imide that has an acid structure and a quinone ring structure. The polyimine in the present invention preferably has a ruthenium iodide ratio of 30% or more, more preferably 40% to 99%, still more preferably 45% to 99%. The ruthenium imidization ratio is a ratio of the number of quinone ring structures to the total number of guanidine structures and the number of quinone ring structures of the polyimine. Here, a part of the quinone ring may also be an isoindole ring.

The dehydration ring closure of polylysine is preferably carried out by a method of heating polylysine; or dissolving polylysine in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst to the solution, as needed The method of heating. Among them, the latter method is selected and used.

In the method of adding a dehydrating agent and a dehydration ring-closure catalyst to the above polyamic acid solution, an acid anhydride such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride can be used as the dehydrating agent. The dehydrating agent is preferably used in an amount of from 0.01 mol to 20 mol per mol of the proline structure of polylysine. As the dehydration ring-closing catalyst, for example, a tertiary amine such as pyridine, trimethylpyridine, dimethylpyridine or triethylamine can be used. The dehydration ring-closure catalyst is preferably used in an amount of from 0.01 mol to 10 mol, relative to the dehydrating agent used. The organic solvent used for the dehydration ring-closure reaction is exemplified as an organic solvent exemplified as the organic solvent used in the synthesis of polyglycine. The reaction temperature of the dehydration ring closure reaction is preferably from 0 ° C to 180 ° C, more preferably from 10 ° C to 150 ° C. The reaction time is preferably from 1.0 to 120 hours, more preferably from 2.0 to 30 hours.

This was carried out to obtain a reaction solution containing polyimine. The reaction solution may be directly supplied to the liquid crystal alignment agent, or may be supplied to the liquid crystal alignment agent after removing the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution, or may be subjected to segregation of the polyimine to the liquid crystal alignment. The preparation of the agent, or the isolation of the isolated polyimine, can be prepared for the preparation of the liquid crystal alignment agent. These purification operations can be carried out in accordance with a known method.

<Solid viscosity of polymer>

The poly-proline and polyimine obtained as described above, when it is made into a solution having a concentration of 10% by weight, preferably has 10 mPa. s~800 mPa. The solution viscosity of s is more preferably 15 mPa. s~500 mPa. s solution viscosity. In addition, the solution viscosity (mPa.s) of the above polymer is a good solvent for the use of the polymer (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazole) A polymer solution having a concentration of 10% by weight prepared by using an alkyl ketone or N-ethyl-2-pyrrolidone, and a value measured at 25 ° C using an E-type rotational viscometer.

Moreover, the polystyrene-reduced weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the polyamic acid or polyimine is preferably 1,000 to 500,000, particularly preferably 2,000 to 300,000, and The ratio (Mw/Mn) of the polystyrene-converted number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is preferably 15 or less, and particularly preferably 10 or less. By making it such a molecular weight range, good alignment and stability of a liquid crystal display element can be ensured.

<solvent>

The liquid crystal alignment agent of the present invention is obtained by dissolving at least one of polyamine and polyimine in an organic solvent. The liquid crystal alignment agent of the present invention contains a group selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, and a compound represented by the following formula (1). The group of at least one solvent (B) is an essential component. Each of these solvents (B) has a high boiling point and a high solubility of polyglycolic acid or polyimine. Therefore, even in the case of printing over a long period of time, the solvent is less volatilized from the printing machine, and precipitation of the polymer can be suppressed.

(In the formula (1), R ¹ and R ² each independently represent a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or a monovalent group containing -O- between the carbon-carbon bonds of the hydrocarbon group, and R ¹ And R ² may be bonded to each other to form a cyclic structure. R ³ is an alkyl group having 1 to 6 carbon atoms)

The hydrocarbon group having 1 to 6 carbon atoms in R ¹ and R ² in the formula (1) may be saturated or unsaturated. Further, R ¹ and R ² may contain "-O-" between the carbon-carbon single bonds in the hydrocarbon group having 1 to 6 carbon atoms. Specific examples of R ¹ and R ² include, for example, an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group, and may include "-O- between the carbon-carbon bonds of the groups. "The base." Further, in the formula (1), R ¹ and R ² may be the same or different from each other.

Here, examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, a second butyl group, an isobutyl group, a t-butyl group, and a pentyl group. Heji and so on. Examples of the alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group and the like. Examples of the aromatic hydrocarbon group include a phenyl group and the like.

R ¹ and R ² may also form a ring together with a nitrogen atom to which R ¹ and R ² are bonded by mutual bonding. Examples of the ring formed by bonding R ¹ and R ^{2 to} each other include a pyrrolidine ring and an acridine ring. Further, a monovalent chain hydrocarbon group such as a methyl group may be bonded to the rings.

R ¹ and R ^{2 are} preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group.

The alkyl group having 1 to 6 carbon atoms in R ³ may be linear or branched, and specifically, exemplified in the description of the alkyl group having 1 to 6 carbon atoms of R ¹ and R ² described above. base.

Specific examples of the compound represented by the above formula (1) include, for example, 3- Butoxy-N,N-dimethylpropanamide, 3-methoxy-N,N-dimethylpropanamide, 3-hexyloxy-N,N-dimethylpropionamide, different Propoxy-N-isopropyl-propionamide, n-butoxy-N-isopropyl-propionamide, and the like.

From the viewpoint of the solubility of the polymer contained in the liquid crystal alignment agent with respect to the solvent, the solvent (B) is preferably used in an amount of preferably 5% by weight or more, and more preferably used, from all the solvents contained in the liquid crystal alignment agent. 10% by weight or more. In addition, the upper limit of the content of the solvent (B) is preferably 90% by weight or less, more preferably 60% by weight or less, and still more preferably 50% by weight or less based on the total amount of the solvent contained in the liquid crystal alignment agent. . Further, the solvent (B) may be used alone or in combination of two or more.

Examples of the solvent to be used in the preparation of the liquid crystal alignment agent of the present invention include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, and N other solvents than the solvent (B). , N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, Methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-ether (butyl cellosolve), Ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol single Methyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether (DPM), diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisoamyl ether, carbonic acid Diester, propylene carbonate and the like. These solvents may be used singly or in combination of two or more.

The liquid crystal alignment agent of the present invention preferably contains dipropylene glycol monomethyl ether (DPM) as the above other solvent. As a liquid crystal alignment agent By using the solvent (B) in combination with DPM, the solvent can be further improved in long-term printability.

<Other additives>

The liquid crystal alignment agent of the present invention contains the above-mentioned polymer and solvent as essential components, and may contain other components as needed. Examples of the other component include a polymer other than the specific polymer, a compound having at least one epoxy group in the molecule (hereinafter referred to as "epoxy group-containing compound"), and at least one propylene oxide in the molecule. A compound of a group (hereinafter referred to as "a compound containing an oxypropylene group"), a functional decane compound, or the like.

[Other polymers]

The other polymers described above can be used to improve solution properties or electrical properties. Examples of the other polymer include polylysine (hereinafter referred to as "other polyamine") obtained by reacting a diamine containing no compound (a1) with tetracarboxylic dianhydride, and the other polylysine. Polyimine (hereinafter referred to as "other polyimine"), polyphthalate, polyester, polyamine, polyoxane, cellulose derivative, polyoxymethylene, poly A styrene derivative, a poly(styrene-phenylmaleimide) derivative, a poly(meth)acrylate, or the like. Further, examples of the tetracarboxylic dianhydride and the diamine for synthesizing other polyamines and other polyimines include compounds exemplified as the compound for synthesizing the above polymer (A).

When the other polymer is added to the liquid crystal alignment agent, the compounding ratio is preferably 50% by weight or less, more preferably 0.1% by weight to 40% by weight, even more preferably based on the total amount of the polymer in the composition. It is from 0.1% by weight to 30% by weight.

[Epoxy group-containing compound]

The epoxy group-containing compound can be used to improve the adhesion of the liquid crystal alignment film to the surface of the substrate. Here, examples of the epoxy group-containing compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and new Pentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromo neopentyl glycol diglycidyl ether , N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N ',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N-diglycidyl-benzylamine, N,N-diglycidyl-aminomethyl ring Hexane, N,N-diglycidyl-cyclohexylamine and the like are preferred epoxy compounds.

Further, as an example of the epoxy group-containing compound, an epoxy group-containing polyorganosiloxane may be used as disclosed in International Publication No. 2009/096598.

When the epoxy compound is added to the liquid crystal alignment agent, the compounding ratio is preferably 40 parts by weight or less, more preferably 0.1 parts by weight, based on 100 parts by weight of the total of the polymer contained in the liquid crystal alignment agent. ~30 parts by weight.

[Compound containing propylene oxide group]

The propylene oxide group-containing compound can be used to improve the mechanical strength of the liquid crystal alignment film or the adhesion to the surface of the substrate. Here, examples of the propylene oxide group-containing compound include 1,4-bis{[(3-ethyl-3-epoxypropenyl)methoxy]methyl}benzene, and two [2-(3-epoxy). Propyl)butyl]ether, 1,4-bis[(3-ethylepoxypropan-3-yl)methoxy]benzene, 1,3-bis[(3-ethylepoxypropane-3- Base) Oxy]benzene, 4,4'-bis[(3-ethylepoxypropan-3-yl)methoxy]biphenyl, 2,2'-bis[(3-ethyl-3-epoxypropane) Methoxy]biphenyl, 3,3',5,5'-tetramethyl[4,4'-bis(3-ethylepoxypropan-3-yl)methoxy]biphenyl, 2 ,7-bis[(3-ethylepoxypropan-3-yl)methoxy]naphthalene, 4,4'-bis[(1-ethyl-3-epoxypropenyl)methyl]thiodi Phenyl sulfide, 2,3-bis[(3-ethyl propylene oxide-3-yl)methoxymethyl]norbornane, 2,2-dimethyl-1,3-O-bis[( 3-ethyl propylene oxide-3-yl)methyl]-propane-1,3-diol, 2,4,6-O-tris[(3-ethyl propylene oxide-3-yl)methyl a cyanuric acid of cyanuric acid, propylene oxide sesquioxane, 3-ethyl-3-hydroxymethyl propylene oxide, ETARNACOLL OXBP (manufactured by Ube Industries Co., Ltd.), 3, 3' -(1,3-(2-methylenyl)propanediylbis(oxymethylene)) bis-(3-ethyl propylene oxide), 1,2-bis[(3-ethyl-3) -Epoxypropenyl methoxy)methyl]ethane, dicyclopentenyl bis(3-ethyl-3-epoxypropanemethyl)ether, triethylene glycol bis(3-ethyl-3 -Epoxypropanemethyl)ether, trimethylolpropane tris(3-ethyl-3-epoxypropanemethyl)ether, 1,4-bis(3-ethyl-3) - propylene oxide methoxy) butane, pentaerythritol tris(3-ethyl-3-epoxypropanemethyl) ether, di-trimethylolpropane tetrakis(3-ethyl-3-epoxypropane Methyl)ether and the like.

When the compound containing a propylene oxide group is blended, the compounding ratio is preferably 40 parts by weight or less, and more preferably 30 parts by weight or less based on 100 parts by weight of the total of the polymer.

[functional decane compound]

The above functional decane compound can be used to improve the printability of the liquid crystal alignment agent. Examples of such a functional decane compound include 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 2-aminopropyltrimethoxydecane, and 2-aminopropyltri Ethoxy decane, N-(2-aminoethyl)-3- Aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, 3-ureidopropyltrimethoxydecane, 3-ureidopropyl Triethoxy decane, N-ethoxycarbonyl-3-aminopropyltrimethoxydecane, N-ethoxycarbonyl-3-aminopropyltriethoxydecane, N-triethoxy矽alkylpropyltriethylenetriamine, N-trimethoxyformamidopropyltriethylenetriamine, 10-trimethoxydecyl-1,4,7-triazadecane, 10-triethyl Oxidylalkyl-1,4,7-triazadecane, 9-trimethoxydecyl-3,6-diazadecyl acetate, 9-trimethoxydecyl-3,6- Diazepine acetate, 9-triethoxydecyl-3,6-diazaindolyl acetate, methyl 9-trimethoxydecyl-3,6-diazadecanoate , 9-triethoxydecyl-3,6-diazepine, methyl N-benzyl-3-aminopropyltrimethoxydecane, N-benzyl-3-aminopropyl Ethoxy decane, N-phenyl-3-aminopropyltrimethoxydecane, N-phenyl-3-aminopropyltriethoxydecane, glycidoxymethyltrimethoxydecane, shrinkage Glyceryloxymethyltriethoxydecane, 2 - glycidoxyethyl trimethoxy decane, 2-glycidoxyethyl triethoxy decane, 3-glycidoxy propyl trimethoxy decane, 3-glycidoxy propyl triethoxy Base decane and the like.

When the functional decane compound is added to the liquid crystal alignment agent, the compounding ratio is preferably 2 parts by weight or less, and more preferably 0.02 parts by weight to 0.2 parts by weight based on 100 parts by weight of the total of the polymer.

The solid content concentration in the liquid crystal alignment agent of the present invention (the ratio of the total weight of components other than the solvent in the liquid crystal alignment agent to the total weight of the liquid crystal alignment agent) can be appropriately selected in consideration of viscosity, volatility, and the like. It is preferably in the range of 1% by weight to 10% by weight. That is, the liquid crystal alignment agent of the present invention is applied to the surface of the substrate as described later, and is preferably heated. When a coating film which is a liquid crystal alignment film or a coating film which becomes a liquid crystal alignment film is formed, in this case, when the solid content concentration is less than 1% by weight, the film thickness of the coating film is too small to obtain a good liquid crystal alignment film. . On the other hand, when the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes too large to obtain a favorable liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases to cause deterioration of coating properties.

A particularly preferable range of the solid content concentration varies depending on the method used when the liquid crystal alignment agent is applied onto the substrate. For example, in the case of using the spin coating method, the solid content concentration is particularly preferably in the range of 1.5% by weight to 4.5% by weight. In the case of using the printing method, it is particularly preferable to set the solid content to a range of 3% by weight to 9% by weight, thereby making the solution viscosity 12 mPa. s~50 mPa. The scope of s. In the case of using the inkjet method, it is particularly preferable to set the solid content to a range of 1% by weight to 5% by weight, thereby making the solution viscosity 3 mPa. s~15 mPa. The scope of s.

The temperature at which the liquid crystal alignment agent of the present invention is prepared is preferably from 10 ° C to 50 ° C, and more preferably from 20 ° C to 30 ° C.

<Liquid alignment film and liquid crystal display element>

The liquid crystal alignment film of the present invention can be formed by a liquid crystal alignment agent prepared as described above. Further, the liquid crystal display element of the present invention comprises a liquid crystal alignment film formed using the liquid crystal alignment agent of the present invention. The liquid crystal display device of the present invention can be applied to a horizontal alignment type operation mode such as an IPS type, a TN type, an STN type, or an FFS type, and can also be applied to a vertical alignment type operation mode such as a VA type.

Hereinafter, a method for producing a liquid crystal display device of the present invention will be described, and in the description, a method for producing a liquid crystal alignment film of the present invention is also added. To illustrate. The liquid crystal display element of the present invention can be produced, for example, by the following steps (1) to (3). Step (1) uses different substrates depending on the desired mode of operation. Step (2) and step (3) are common to each operation mode.

[Step (1): Formation of coating film]

First, the liquid crystal alignment agent of the present invention is applied onto a substrate, and then the coated surface is heated to form a coating film on the substrate.

(1-1) When manufacturing a TN type, STN type or VA type liquid crystal display element, two substrates each having a patterned transparent conductive film are provided as a pair, preferably by offset printing or spin coating, The liquid crystal alignment agent of the present invention is applied to each of the transparent conductive film forming faces by a roll coating method or an inkjet printing method, and secondly, each coated surface is heated (preferably including preheating (prebake) and simmering ( A post-baking two-stage heating) forms a coating film. Here, as the substrate, for example, glass such as float glass or soda glass may be used; and polyethylene terephthalate, polybutylene terephthalate, polyether oxime, polycarbonate, poly(alicyclic olefin) may be used. A transparent substrate such as plastic. As the transparent conductive film provided on one surface of the substrate, a NESA film containing tin oxide (SnO ₂ ) (manufactured by PPG Corporation, registered trademark), and indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) may be used. ITO film, etc. In order to obtain a patterned transparent conductive film, for example, a method of forming a pattern by photolithography after forming a transparent conductive film without a pattern, a method of using a mask having a desired pattern when forming a transparent conductive film, or the like can be used. . When the liquid crystal alignment agent is applied, in order to improve the adhesion between the surface of the substrate and the transparent conductive film and the coating film, the surface of the substrate on which the coating film is to be formed may be coated with a functional decane compound or a functional titanium. Pretreatment of compounds and the like.

After coating the liquid crystal alignment agent, it is preferred to carry out preheating (prebaking) in order to prevent the applied alignment agent from sagging or the like. The prebaking temperature is preferably from 30 ° C to 200 ° C, more preferably from 40 ° C to 150 ° C, and particularly preferably from 40 ° C to 100 ° C. The prebaking time is preferably from 0.25 minutes to 10 minutes, more preferably from 0.5 minutes to 5 minutes. Thereafter, the solvent is completely removed, and if necessary, a calcination (post-baking) step is carried out for the purpose of thermally imidating the proline structure present in the polymer. The calcination (post-baking) temperature is preferably from 80 ° C to 300 ° C, more preferably from 120 ° C to 250 ° C. The post-baking time is preferably from 5 minutes to 200 minutes, more preferably from 10 minutes to 100 minutes. As described above, the film thickness of the formed film is preferably 0.001 μm to 1 μm, and more preferably 0.005 μm to 0.5 μm.

(1-2) When manufacturing an IPS type or FSS type liquid crystal display element, the liquid crystal alignment agent of the present invention is applied to an electrode provided separately (the electrode includes a transparent conductive film or a metal film patterned into a comb type) The electrode forming surface of the substrate and one surface of the counter substrate on which the electrode is not provided are heated next to each of the coated surfaces to form a coating film. The material of the substrate and the transparent conductive film used at this time, the coating method, the heating conditions after coating, the patterning method of the transparent conductive film or the metal film, the pretreatment of the substrate, and the preferred film thickness of the formed coating film, and The above (1-1) is the same. As the metal film, for example, a film containing a metal such as chromium can be used.

In any of the above (1-1) and (1-2), the liquid crystal alignment agent is applied onto the substrate, and then the organic solvent is removed to form a coating film which becomes an alignment film. In this case, when the polymer contained in the liquid crystal alignment agent of the present invention is a polyphthalic acid or a ruthenium iodide polymer having a quinone ring structure and a phthalic acid structure, it may be formed after the coating film is formed. Further, heating is carried out to carry out a dehydration ring-closure reaction to prepare a coating film which is further imidized.

[Step (2): Friction treatment]

In the case of manufacturing a TN type, STN type, IPS type, or FFS type liquid crystal display element, the following rubbing treatment is performed: a roll wound with a cloth (the cloth containing fibers such as nylon, rayon, cotton, etc.) is used. The coating film formed in the above step (1) is rubbed in a fixed direction. Thereby, the alignment ability of the liquid crystal molecules is imparted to the coating film, thereby becoming a liquid crystal alignment film. On the other hand, in the case of manufacturing a VA liquid crystal display element, the coating film formed in the above step (1) can be directly used as a liquid crystal alignment film, and the coating film can be subjected to a rubbing treatment.

Further, the liquid crystal alignment film formed as described above may be subjected to the following treatment so that the liquid crystal alignment film has different liquid crystal alignment ability in each region: the liquid crystal alignment film is irradiated by irradiating a part of the liquid crystal alignment film with ultraviolet rays. The treatment of the pretilt angle change of a part of the area; or after the resist film is formed on a part of the surface of the liquid crystal alignment film, the rubbing treatment is performed in a direction different from the previous rubbing treatment, and then the treatment of the resist film is removed. In this case, the visual field characteristics of the obtained liquid crystal display element can be improved.

[Step (3): Construction of liquid crystal cell]

Two substrates which were formed as described above and formed with a liquid crystal alignment film were prepared, and liquid crystals were placed between the two substrates arranged in the opposite direction to produce a liquid crystal cell. Here, in the case where the coating film is subjected to the rubbing treatment, the two substrates are arranged to face each other at a predetermined angle, for example, orthogonal or anti-parallel, in the rubbing directions of the respective coating films.

When manufacturing a liquid crystal cell, the following two methods are mentioned, for example.

The first method is a method known from the previous one. First, each When the liquid crystal alignment films are opposed to each other, the two substrates are opposed to each other with a gap (cell gap) therebetween, and the peripheral portions of the two substrates are bonded together using a sealant, and the cell gap is defined by the surface of the substrate and the sealant. After the inside of the filling liquid crystal is injected, the injection hole is sealed, whereby the liquid crystal cell can be manufactured.

The second method is called the ODF (One Drop Fill) method. For example, an ultraviolet curable sealing material is applied to a predetermined position on one of the two substrates on which the liquid crystal alignment film is formed, and liquid crystal is further added to a predetermined number of portions on the liquid crystal alignment film surface, and then liquid crystal alignment is performed. The liquid crystal cell can be manufactured by laminating another substrate and laminating the liquid crystal on the entire surface of the substrate, and then irradiating the entire surface of the substrate with ultraviolet light to cure the sealing agent.

In the case of using any method, it is preferred to further heat the liquid crystal cell produced as described above until the liquid crystal used becomes an isotropic phase, and then slowly cool to room temperature, thereby removing the liquid crystal filling. Flow alignment.

Next, the liquid crystal display element of the present invention is obtained by laminating a polarizing plate on the outer surface of the liquid crystal cell.

As the sealant, for example, an epoxy resin containing a curing agent and an alumina ball as a spacer can be used.

The liquid crystal may be a nematic liquid crystal or a smectic liquid crystal. Among them, a nematic liquid crystal is preferable, and for example, a Schiff base liquid crystal, an oxidized azo liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, or an ester can be used. Liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane liquid crystal, cubic liquid crystal, and the like. Further, for the liquid crystals, for example, the following compounds may be added and used: cholesteryl chloride, cholesteryl phthalate, A cholesteric liquid crystal such as cholesteryl carbonate; a chiral agent commercially available as a trade name "C-15" or "CB-15" (manufactured by Merck & Co., Inc.); p-methoxybenzylidene-p-amino group A ferroelectric liquid crystal such as -2-methylbutyl cinnamate.

The polarizing plate to be bonded to the outer surface of the liquid crystal cell may be a polarizing film called "H film" sandwiched between a cellulose acetate protective film (the H film is one surface in which polyvinyl alcohol is stretched to absorb iodine on one side). A polarizing film formed of a polarizing film or a polarizing plate including the H film itself.

The liquid crystal display element of the present invention can be effectively applied to various devices, such as a clock, a portable game machine, a word processor, a notebook computer, a car navigation system, a camcorder, a personal digital assistant (PDA), a digital camera, Used in display devices such as mobile phones, smart phones, various displays, and LCD TVs.

[Example]

Hereinafter, the present invention will be more specifically illustrated by the examples, but the present invention is not limited by the examples.

The solution viscosity of each polymer solution in the synthesis example and the oxime imidization ratio of polyimine can be measured by the following methods.

[Solid viscosity of polymer solution]

The solution viscosity (mPa.s) of the polymer solution can be measured by using a T-type rotational viscometer at 25 ° C for a solution having a polymer concentration adjusted to 10% by weight using a predetermined solvent.

[醯Iminization rate of polyimine]

The polyimine solution is put into pure water, and the obtained precipitate is dried under reduced pressure at room temperature, and then dissolved in dimethyl hydrazine oxime, and measured at room temperature with tetramethyl decane as a reference substance. ¹ H-NMR. From the obtained ¹ H-NMR spectrum, the oxime imidization ratio [%] was determined by the following formula (1).

醯imination rate [%]=(1-A ¹ /A ² ×α)×100...(1)

(In the formula (1), A ¹ is the peak area of the proton derived from the NH group appearing near the chemical shift of 10 ppm, A ² is the peak area derived from other protons, and α is the proton relative to the polymer Proportion of the number of protons of the NH group in the precursor (polyproline)

<Synthesis of Polymer (A)> [Synthesis Example 1: Synthesis of Polyimine (PI-1)]

2,3,5-tricarboxycyclopentyl acetic acid dianhydride (TCA) as a tetracarboxylic dianhydride 22.4 g (0.1 mol), p-phenylenediamine (PDA) as a diamine 2.2 g (0.02 mol) , 3,5-diaminobenzoic acid cholesteryl ester (HCDA) 10.5 g (0.02 mol), cholesteryloxy-2,4-diaminobenzene (HCODA) 4.9 g (0.01 Mo Ears and 3,5-diaminobenzoic acid (DAB) 7.6 g (0.05 mol) were dissolved in N-methyl-2-pyrrolidone (NMP) 190 g, and reacted at 60 ° C for 6 hours to obtain A solution containing 20% by weight of polylysine. Regarding the obtained polyaminic acid solution, NMP was added to prepare a solution having a polyglycine concentration of 10% by weight, and the solution viscosity was determined to be 88 mPa. s.

Next, 442 g of NMP was added to the obtained polyamic acid solution, and 11.9 g of pyridine and 15.3 g of acetic anhydride were added to carry out a dehydration ring-closure reaction at 110 ° C for 4 hours. After the dehydration ring-closing reaction, the solvent in the system is subjected to solvent replacement with a new NMP (by this operation, the pyridine and acetic anhydride used in the dehydration ring-closure reaction are removed to the outside of the system. The same applies hereinafter), thereby obtaining There is a 22% by weight solution of polyimine (PI-1) having a ruthenium iodide ratio of about 65%. A small amount of the obtained polyimine solution was added, and a solution having a concentration of 10% by weight of polyamidiamine was added to obtain a solution viscosity of 55 mPa. s.

[Synthesis Example 2: Synthesis of Polyimine (PI-2)]

22.4 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 5.4 g (0.05 mol) of PDA as diamine, 10.5 g (0.02 mol) of HCDA, 4.9 g (0.01 mol) of HCODA, and 4, 4'-Diamino-1,1'-biphenyl-2,2'-dicarboxylic acid (DBCA) 5.4 g (0.02 mol) was dissolved in NMP 195 g and reacted at 60 ° C for 6 hours to obtain A solution containing 20% by weight of polylysine. Regarding the obtained polyaminic acid solution, the solution viscosity of the solution was determined to be 33 mPa by adding NMP to a solution having a polyglycine concentration of 10% by weight. s.

Next, 452 g of NMP was added to the obtained polyamic acid solution, and 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and a dehydration ring-closure reaction was carried out at 110 ° C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was subjected to solvent replacement with a new NMP, whereby a solution containing 22% by weight of polyimine (PI-2) having a ruthenium iodide ratio of about 67% was obtained. A small amount of the obtained polyimine solution was added, and a solution having a concentration of 10% by weight of polyamidiamine was added to obtain a solution viscosity of 29 mPa. s.

[Synthesis Example 3: Synthesis of Polyimine (PI-3)]

22.4 g (0.10 mol) of TCA as tetracarboxylic dianhydride, 5.4 g (0.05 mol) of PDA as diamine, HCDA 10.5 g (0.02 mol), HCODA 5.0 g (0.01 mol) and double ( 4-amino-3-carboxyphenyl)methane (BCPM) 5.7 g (0.02 mol) dissolved in NMP 196 g at 60 ° C The reaction was carried out for 6 hours to obtain a solution containing 20% by weight of polyamic acid. Regarding the obtained polyaminic acid solution, the solution viscosity of the solution was determined to be 34 mPa by adding NMP to a solution having a polyglycine concentration of 10% by weight. s.

Next, 455 g of NMP was added to the obtained polyamic acid solution, and 11.9 g of pyridine and 15.3 g of acetic anhydride were added to carry out a dehydration ring-closure reaction at 110 ° C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was subjected to solvent replacement with a new NMP, thereby obtaining a solution containing 22% by weight of polyimine (PI-3) having a ruthenium iodide ratio of about 73%. A small amount of the obtained polyimine solution was added, and a solution having a concentration of 10% by weight of polyamidiamine was added to obtain a solution viscosity of 29 mPa. s.

[Synthesis Example 4: Synthesis of Polyimine (PI-4)]

22.4 g (0.10 mol) of TCA as tetracarboxylic dianhydride, 4.3 g (0.04 mol) of PDA as diamine, 10.5 g (0.02 mol) of HCDA, 4.9 g (0.01 mol) of HCODA, 4, 4'-Diaminodiphenylmethane (DDM) 4.0 g (0.02 mol) and DAB 1.5 g (0.01 mol) were dissolved in NMP 190 g, and reacted at 60 ° C for 6 hours to obtain 20 weights. A solution of % polyaminic acid. Regarding the obtained polyaminic acid solution, the solution viscosity of the solution was determined to be 102 mPa by adding NMP to a solution having a polyglycine concentration of 10% by weight. s.

Next, 442 g of NMP was added to the obtained polyamic acid solution, and 7.9 g of pyridine and 10.2 g of acetic anhydride were added to carry out a dehydration ring-closure reaction at 110 ° C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was subjected to solvent replacement with a new NMP, whereby a solution containing 22% by weight of polyimine (PI-4) having a ruthenium iodide ratio of about 52% was obtained. A small amount of the obtained polyimine solution was added, and NMP was added to prepare a polyimine concentration of 10% by weight. The solution viscosity measured by % solution is 60 mPa. s.

[Synthesis Example 5: Synthesis of Polyimine (PI-5)]

22.5 g (0.1 mol) of TCA as tetracarboxylic dianhydride, PDA 4.3 g (0.04 mol) as diamine, HCDA 10.5 g (0.02 mol), HCODA 5.0 g (0.01 mol), DBCA 2.7 g (0.01 mol) and DDM 4.0 g (0.02 mol) were dissolved in NMP 196 g, and reacted at 60 ° C for 6 hours to obtain a solution containing 20% by weight of polyglycine. Regarding the obtained polyaminic acid solution, the solution viscosity of the solution was determined to be 44 mPa by adding NMP to a solution having a polyglycine concentration of 10% by weight. s.

Next, 455 g of NMP was added to the obtained polyamic acid solution, and 7.9 g of pyridine and 10.2 g of acetic anhydride were added to carry out a dehydration ring-closure reaction at 110 ° C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was subjected to solvent replacement with a new NMP, whereby a solution containing 22% by weight of polyimine (PI-5) having a ruthenium iodide ratio of about 50% was obtained. A small amount of the obtained polyimine solution was added, and NMP was added to prepare a solution having a concentration of 10% by weight of polyimine, and the viscosity of the solution was 31 mPa. s.

[Synthesis Example 6: Synthesis of Polyimine (PI-6)]

2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride (BODA) 25.1 g (0.1 mol) as tetracarboxylic dianhydride, as two Amine PDA 2.2 g (0.02 mol), HCDA 10.5 g (0.02 mol), HCODA 5.0 g (0.01 mol) and DAB 7.6 g (0.05 mol) were dissolved in NMP 202 g at 60 ° C. After a small reaction, a solution containing 20% by weight of polyamic acid was obtained. Regarding the obtained polyaminic acid solution, the solution viscosity of the solution was determined to be 44 mPa by adding NMP to a solution having a polyglycine concentration of 10% by weight. s.

Next, 468 g of NMP was added to the obtained polyaminic acid solution, and 11.9 g of pyridine and 15.4 g of acetic anhydride were added to carry out a dehydration ring-closure reaction at 110 ° C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was subjected to solvent replacement with a new NMP, thereby obtaining a solution containing 22% by weight of polyimine (PI-6) having a ruthenium iodide ratio of about 63%. A small amount of the obtained polyimine solution was added, and a solution having a concentration of 10% by weight of polyamidiamine was added to the solution to determine a solution viscosity of 33 mPa. s.

[Synthesis Example 7: Synthesis of Polyimine (PI-7)]

22.4 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 2.2 g (0.02 mol) of PDA as diamine, HCDA 10.4 g (0.02 mol), HCODA 4.9 g (0.01 mol), DAB 3.8 g (0.025 mol) and 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indole-5-amine/1-(4-amino group a mixture of phenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indole-6-amine (TMDA) 6.7 g (0.025 mol) dissolved in NMP 202 g at 60 ° C The reaction was carried out for 6 hours to obtain a solution containing 20% by weight of polyamic acid. With respect to the obtained polyaminic acid solution, the solution viscosity of the solution was determined to be 81 mPa by adding NMP to a solution having a polyglycine concentration of 10% by weight. s.

Next, 468 g of NMP was added to the obtained polyaminic acid solution, and 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and a dehydration ring-closure reaction was carried out at 110 ° C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was subjected to solvent replacement with a new NMP, thereby obtaining a solution containing 22% by weight of polyimine (PI-7) having a ruthenium iodide ratio of about 63%. A small amount of the obtained polyimine solution was added, and a solution having a concentration of 10% by weight of polyamidiamine was added to obtain a solution viscosity of 49 mPa. s.

[Synthesis Example 8: Synthesis of Polyimine (PI-8)]

BODA 25.0 g (0.1 mol) as tetracarboxylic dianhydride, PDA 4.3 g (0.04 mol) as diamine, HCDA 10.4 g (0.02 mol), HCODA 4.9 g (0.01 mol), DAB 3.0 g (0.02 mol) and TMDA 2.7 g (0.01 mol) were dissolved in NMP 202 g, and reacted at 60 ° C for 6 hours to obtain a solution containing 20% by weight of polyglycolic acid. Regarding the obtained polyaminic acid solution, the solution viscosity of the solution was determined to be 49 mPa by adding NMP to a solution having a polyglycine concentration of 10% by weight. s.

Next, 468 g of NMP was added to the obtained polyamic acid solution, and 7.9 g of pyridine and 10.2 g of acetic anhydride were added to carry out a dehydration ring-closure reaction at 110 ° C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was subjected to solvent replacement with a new NMP, whereby a solution containing 22% by weight of polyimine (PI-8) having a ruthenium iodide ratio of about 49% was obtained. A small amount of the obtained polyimine solution was added, and a solution having a concentration of 10% by weight of polyamidiamine was added to the solution to determine a solution viscosity of 34 mPa. s.

[Synthesis Example: Synthesis of Polyimine (PI-9)]

22.5 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 7.6 g (0.07 mol) of PDA as diamine, HCDA 10.5 g (0.02 mol) and HCODA 5.0 g (0.01 mol) were dissolved in NMP 182 g was reacted at 60 ° C for 6 hours to obtain a solution containing 20% by weight of polyamic acid. With respect to the obtained polyaminic acid solution, the solution viscosity of the solution was determined to be 95 mPa by adding NMP to a solution having a polyglycine concentration of 10% by weight. s.

Next, 423 g of NMP was added to the obtained polyaminic acid solution, and 11.9 g of pyridine and 15.4 g of acetic anhydride were added, and a dehydration ring-closure reaction was carried out at 110 ° C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with a new NMP solvent, thereby obtaining 22% by weight of yttrium. The amination rate was about 67% of a solution of polyimine (PI-9). A small amount of the obtained polyimine solution was added, and a solution having a concentration of 10% by weight of polyamidiamine was added to obtain a solution viscosity of 49 mPa. s.

[Synthesis Example 10: Synthesis of Polyimine (PI-10)]

22.3 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 13.8 g (0.07 mol) of DDM as diamine, HCDA 10.4 g (0.02 mol) and HCODA 4.9 g (0.01 mol) were dissolved in NMP In 206 g, the reaction was carried out at 60 ° C for 6 hours to obtain a solution containing 20% by weight of polyamic acid. With respect to the obtained polyaminic acid solution, a solution having a polyglycine concentration of 10% by weight was added to obtain a solution viscosity of 100 mPa. s.

Next, 478 g of NMP was added to the obtained polyamic acid solution, and 11.8 g of pyridine and 15.2 g of acetic anhydride were added, and a dehydration ring-closure reaction was carried out at 110 ° C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was subjected to solvent replacement with a new NMP, thereby obtaining a solution containing 22% by weight of polyimine (PI-10) having a ruthenium iodide ratio of about 66%. A small amount of the obtained polyimine solution was added, and the solution having a concentration of 10% by weight of polyamidiamine was added to NMP to determine a solution viscosity of 59 mPa. s.

[Synthesis Example 11: Synthesis of Polyimine (PI-11)]

A polyaminic acid solution was obtained in the same manner as in the above Synthesis Example 1 except that 1,3-dimethyl-2-imidazolidinone (DMI) was used instead of NMP. The solution viscosity of the obtained polylysine solution was determined by adding DMI to a solution having a polyglycine concentration of 10% by weight. The viscosity of the solution was 89 mPa. s.

Next, the obtained polyaminic acid solution was used to carry out the synthesis of polyimine. The synthesis was carried out in the same manner as in the above Synthesis Example 1 except that DMI was used instead of NMP, whereby a yield of ruthenium containing 22% by weight was obtained. A solution of 65% polyimine (PI-11). A small amount of the obtained polyimine solution was added, and a solution having a concentration of 10% by weight of polyamidiamine was added to DMI to determine a solution viscosity of 57 mPa. s.

[Synthesis Example 12: Synthesis of Polyimine (PI-12)]

A polyaminic acid solution was obtained in the same manner as in the above Synthesis Example 2 except that N-ethyl-2-pyrrolidone (NEP) was used instead of NMP. The solution viscosity of the solution obtained by adding NEP to a solution having a polyglycine concentration of 10% by weight is 32 mPa. s.

Next, the obtained polyaminic acid solution was used to carry out the synthesis of polyimine. In the same manner as in the above Synthesis Example 2 except that NEP was used instead of NMP, a solution containing 22% by weight of polyimine (PI-12) having a ruthenium iodide ratio of about 66% was obtained. A small amount of the obtained polyimine solution was added, and a solution having a concentration of 10% by weight of polyethylenimine was added to NEP to determine a solution viscosity of 28 mPa. s.

<Modulation of liquid crystal alignment agent> [Example 1]

Adding NMP, ethylene glycol mono-n-butyl ether (BC) and 1,3-dimethyl-2-imidazolidinone (DMI) as a solvent to a solution containing polyimine (PI-1) as a polymer A solvent having a solvent composition of NMP:BC: DMI = 30:50:20 (weight ratio) and a solid concentration of 6.5% by weight was prepared. This solution was filtered using a filter having a pore size of 1 μm to prepare a liquid crystal alignment agent (S-1).

[Example 2 to Example 33 and Comparative Example 1 to Comparative Example 6]

The polyimine and the solvent composition used were changed as described in the following Table 1, except that the same method as in the above Example 1 was used. Liquid crystal alignment agent (S-2) ~ liquid crystal alignment agent (S-33) and liquid crystal alignment agent (SR-1) ~ liquid crystal alignment agent (SR-6).

<Printability evaluation>

In the case of the above-described liquid crystal alignment agent, the printability (long-term printability) in the case of printing on a substrate was evaluated for a long time. Evaluation was performed in the following manner. First, for each liquid crystal alignment agent of the prepared liquid crystal alignment agent, a liquid crystal alignment film printing machine (manufactured by Nippon Photo Printing Co., Ltd., Angstromer, model "S40L-532") was used for the liquid crystal alignment agent on the anilox roller. The amount of the dropwise addition was applied to the transparent electrode surface of the glass substrate with the transparent electrode containing the ITO film under the condition of 20 drops (about 0.2 g). The coating on the substrate was performed 20 times at a time interval of 1 minute using a new substrate.

Next, the liquid crystal alignment agent was dispensed (single pass) on the anilox roll at intervals of 1 minute, and the anilox roll was brought into contact with the printing plate at this time, and this operation (hereinafter referred to as "empty operation" was collectively performed 10 times (in During this period, printing on the glass substrate is not performed). In addition, this dry operation is not performed in the actual manufacturing flow of the liquid crystal display element, but is an operation performed by intentionally performing printing of the liquid crystal alignment agent under severe conditions.

After 10 empty runs, the glass substrate was used for official printing. In the main printing, after the idling operation, five substrates were placed at intervals of 30 seconds, and each substrate coated with the liquid crystal alignment agent was heated (prebaked) at 80 ° C for 1 minute to remove the solvent, and thereafter, the solvent was removed. Heating (post-baking) was carried out at 200 ° C for 10 minutes to form a coating film having a film thickness of about 80 nm. The coating film was observed with a microscope having a magnification of 20 times, whereby the long-term printability was evaluated. Evaluation is performed in the following manner, starting from the first official printing after the operation When the precipitation of polyimine was not observed, it was excellent (○), and polyimine was observed in the first official printing after the idling operation, but it was not observed when the fifth printing was performed. When the ruthenium was precipitated as good (?), it was observed that the precipitation of polyimine was observed as a defect (x) even after repeated printing for 5 times. The evaluation results are shown in Table 1 below. In addition, it has been found that, in the liquid crystal alignment agent having good printability, precipitation of polyimine is improved (disappeared) when continuously introduced into the substrate.

Furthermore, the number of times of the dry operation was changed to 15 times, 20 times, and 25 times, and the long-term printability of the liquid crystal alignment agent was evaluated in the same manner as described above. The results of the evaluation are also shown in Table 1 below.

<Manufacture of liquid crystal display element> [Manufacturing Example 1]

The liquid crystal alignment agent (S-1) prepared by coating the above-prepared liquid crystal alignment agent (S-1) on a transparent electrode surface of a glass substrate having a transparent electrode including an ITO film having a thickness of 1 mm was carried out on a hot plate at 80 ° C. Minute prebaked. Next, the prebaked substrate was post-baked at 210 ° C for 30 minutes. Thereby, a liquid crystal alignment film having a film thickness of about 80 nm was formed. This operation was repeated to obtain a pair of (two) substrates having a liquid crystal alignment film. Next, an epoxy resin adhesive having an alumina ball having a diameter of 5.5 μm is applied to the outer edge of any of the pair of substrates having the liquid crystal alignment film, and then the liquid crystal alignment film faces are opposed to each other and are crimped. To harden the adhesive. Next, a nematic liquid crystal (manufactured by Merck & Co., Ltd., MLC-6608) was filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an acrylic photocurable adhesive to produce the first Liquid crystal cell (C1-1). Further, a pair of bases with a liquid crystal alignment film is additionally formed by the same method as described above. After the plate was placed in an environment of humidity of 33% and 23° C. for 24 hours, the second liquid crystal cell (C2-1) was produced in the same manner as described above using the pair of substrates.

[Manufacturing Example 2 to Manufacturing Example 35]

The liquid crystal alignment agent to be used is changed to a liquid crystal alignment agent (S-2) to a liquid crystal alignment agent (S-33), a liquid crystal alignment agent (SR-1) to a liquid crystal alignment agent (SR-6), and the like. The first liquid crystal cell (C1-2) to the first liquid crystal cell (C1-33) and the first liquid crystal cell (CR1-1) to the first liquid crystal cell (CR1-6) were produced in the same manner as in the above Production Example 1. And the second liquid crystal cell (C2-2) to the second liquid crystal cell (C2-33), the second liquid crystal cell (CR2-1) to the second liquid crystal cell (CR2-6).

<Evaluation of resturance tolerance>

In the respective liquid crystal cells of the first liquid crystal cell manufactured as described above, a voltage of 3 V was applied at 70 ° C for an application time of 60 μsec and a span of 1670 msec, and then the measurement was performed by using VHR-1 manufactured by Toyo Denki Co., Ltd. The voltage holding ratio after 1670 milliseconds was applied. The value was taken as the initial voltage holding ratio (VHR1) (%). In the same manner, the voltage holding ratio was measured for each liquid crystal cell of the second liquid crystal cell by the same method as described above, and the value was taken as the voltage holding ratio (VHR2) [%] after standing. The voltage holding ratio difference (⊿VHR) (%) between the first liquid crystal cell and the second liquid crystal cell was calculated according to the following mathematical expression (2), and the standing resistance was evaluated from the calculated value. The results are shown in Table 1 below. In addition, the smaller the ⊿VHR, the better the standing tolerance.

⊿VHR(%)=VHR1-VHR2.........(2)

In addition, the symbols of the solvent composition in Table 1 have the following meanings.

a: N-methyl-2-pyrrolidone (NMP)

b: ethylene glycol mono-n-butyl ether (BC)

c: γ-butyrolactone (GBL)

d: 1,3-dimethyl-2-imidazolidinone (DMI)

e: N-ethyl-2-pyrrolidone (NEP)

f: 3-methoxy-N,N-dimethylpropanamide

g: 3-butoxy-N,N-dimethylpropanamide

h: dipropylene glycol monomethyl ether (DPM)

As shown in Table 1, in the liquid crystal alignment agent of the example, precipitation of polyimine was not observed from the first official printing in the main printing after 10 empty runs. In addition, even if the number of times of the idling operation is increased to 20 times and 25 times, no precipitation of polyimine is observed from the first official printing, or even if the precipitation of polyimine is observed, it is officially printed five times. Disappeared at the end. On the other hand, in the liquid crystal alignment agent of the comparative example, when the number of times of the dry operation was increased to 20 times, the precipitation of the polyimine was observed in all of the five official printings. According to these results, it is understood that the liquid crystal alignment agents of Examples 1 to 33 are more difficult to precipitate than the liquid crystal alignment agent of the comparative example, and printability is possible even when printing is continuously performed for a long period of time. (Long-term printability) is also good.

Further, according to the results of Example 6, Example 14, and Example 23, it was found that the long-term printability can be further improved by using DPM as a solvent in combination. Further, in the liquid crystal alignment agents of Examples 26 to 29, the long-term printability is good, and even when the liquid crystal alignment film is allowed to stand for a long period of time, a reduction in voltage holding ratio and a good electrical stability can be maintained. A characteristic liquid crystal alignment film.

Claims (7)

A liquid crystal alignment agent comprising: A) at least one polymer (A) selected from the group consisting of polypyridamines obtained by dehydration ring closure of polyamic acid and polyamic acid, The polyamic acid is obtained by reacting a tetracarboxylic dianhydride with a diamine containing a diamine compound (a1) having one or more carboxyl groups in the molecule; and B) is selected from 1,3-dimethyl-2 At least one solvent (B) of the group consisting of imidazolidinone, N-ethyl-2-pyrrolidone, and a compound represented by the following formula (1), In the formula (1), R ¹ and R ² each independently represent a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or a monovalent group containing -O- between the carbon-carbon bonds of the hydrocarbon group, and R ¹ and R ² may be bonded to each other to form a cyclic structure; and R ³ is an alkyl group having 1 to 6 carbon atoms. The liquid crystal alignment agent according to claim 1, wherein the content of the solvent (B) is 10% by weight or more based on the entire solvent. The liquid crystal alignment agent according to claim 1 or 2, wherein the polymer (A) comprises 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 2,4,6,8 A compound of at least any one of tetracarboxylic bicyclo[3.3.0]octane-2:4,6:8-dianhydride is synthesized as the tetracarboxylic dianhydride. The liquid crystal alignment agent according to claim 1 or 2, wherein the polymer (A) is further used to further comprise 1-(4-aminobenzene) -2,3-dihydro-1,3,3-trimethyl-1H-indole-5-amine and 1-(4-aminophenyl-2,3-dihydro-1,3,3 A compound of at least any one of trimethyl-1H-indol-6-amine is synthesized as the diamine. The liquid crystal alignment agent according to claim 1 or 2, further comprising dipropylene glycol monomethyl ether as a solvent. A liquid crystal alignment film which is formed by using the liquid crystal alignment agent according to any one of the above claims. A liquid crystal display element comprising the liquid crystal alignment film according to item 6 of the patent application.