TW201418847A - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

The invention obtains a liquid crystal alignment film which maintains a good property of high reliability even if under a harsh usage environment. The invention contains a polymer (A) such as a polyimide and a compound (B) represented by formula (1) below. (In the formula, R1 is a hydrogen atom, or a monovalent organic group bonding to a nitrogen atom by a chainlike hydrocarbon group or an alicyclic hydrocarbon group. R2 and R3 are divalent organic groups bonding to the nitrogen atom by the chainlike hydrocarbon group, the alicyclic hydrocarbon group or *-CO-R4-. X1 is a nitrogen-containing aromatic heterocycle, and X2 is a cyclic ether group or a polymerizable unsaturated group. m is 0 or 1, and n is an integer ranging from 1 to 3. When n is equal to 3, m is equal to 0.)

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. In particular, the present invention relates to a liquid crystal alignment agent for preparing a liquid crystal alignment film and a liquid crystal alignment method using the liquid crystal alignment agent. A liquid crystal display element of a film.

Conventionally, regarding the liquid crystal display element, various driving methods have been developed in which the electrode structure or the liquid crystal molecules used are different in physical properties, manufacturing steps, and the like, and for example, a twisted nematic (TN) type or a super twisted nematic (known) Super Twisted Nematic, STN), Vertical Alignment (VA), In-Plane Switching (IPS), Fringe Field Switching (FFS), Polymer Stabilized (Polymer Sustained) Various liquid crystal display elements such as Alignment, PSA). These liquid crystal display elements have a liquid crystal alignment film for aligning liquid crystal molecules. The material of the liquid crystal alignment film is generally made of polyaminic acid or polyimide from the viewpoints of various properties such as heat resistance, mechanical strength, and affinity with liquid crystal.

In order to obtain a liquid crystal display element with high display quality, a liquid crystal alignment film is required. The medium voltage holding ratio is high, or the residual charge when the voltage is applied is small, and the relaxation of the residual charge is fast. In addition, in order to satisfy such a demand, various liquid crystal alignment agents have been proposed (for example, refer to Patent Document 1 and Patent Document 2). Patent Document 1 discloses that a very small amount of a compound having one tertiary amino group in a molecule is contained in a liquid crystal alignment agent together with polyglycine or polyimine. Further, Patent Document 2 discloses that a specific tertiary amine such as vinyl pyridine or N,N-glycidyl aniline or a polyamine obtained by imidating a part of polylysine or polylysine is disclosed. The quinone imine is contained together in the liquid crystal alignment agent.

In addition, in recent years, the liquid crystal display element has been used not only as a display terminal such as a personal computer but also as a liquid crystal television or a car navigation system, a mobile phone, or a smart phone. , information display (information display) and other uses. Along with such versatility, it is conceivable to use a liquid crystal display element in a harsher environment than before. Therefore, as a liquid crystal alignment film, a liquid crystal alignment film which is highly reliable in use in a severe environment is required, and in order to satisfy such a demand, various liquid crystal alignment agents have been proposed (for example, refer to Patent Document 3 or Patent Document 4). . Patent Document 3 and Patent Document 4 disclose liquid crystal alignment agents containing a polyimine having a carboxyl group and a primary amine group having one primary amino group and a nitrogen-containing aromatic heterocyclic ring. A primary amine compound attached to an aliphatic hydrocarbon group.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 08-76128

[Patent Document 2] Japanese Patent Laid-Open No. 09-316200

[Patent Document 3] International Publication No. 2008/013285

[Patent Document 4] International Publication No. 2009/084665

The demand for higher performance of the liquid crystal display element is further improved, and the liquid crystal alignment film is required to exhibit better characteristics than the original liquid crystal alignment film from the viewpoint of exhibiting excellent characteristics in a severe use environment.

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 which is a highly reliable liquid crystal alignment film which can maintain excellent characteristics even under a severe use environment.

The inventors of the present invention have diligently studied to achieve the problems of the prior art as described above, and as a result, have found that by using a liquid crystal alignment agent containing polyglycine or polyimine and containing a specific nitrogen-containing compound. The problem can be solved, and the present invention has been completed. Specifically, the following liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element can be provided by the present invention.

The present invention provides, in one aspect, a liquid crystal alignment agent comprising at least one polymer (A) selected from the group consisting of polylysine, polyphthalate, and polyimine, and the following formula ( 1) the compound (B) represented,

(In the formula (1), R ¹ is a hydrogen atom or a monovalent organic group bonded to a nitrogen atom bonded to R ² and R ³ by a chain hydrocarbon group or an alicyclic hydrocarbon group, and R ² and R ³ are each independently Is a chain hydrocarbon group, an alicyclic hydrocarbon group or *-CO-R ⁴ - (wherein R ⁴ is a divalent chain hydrocarbon group or an alicyclic hydrocarbon group, and * represents a bond with a nitrogen atom bonded to R ¹ ) a divalent organic group bonded to a nitrogen atom to which R ¹ is bonded; X ¹ is a nitrogen-containing aromatic heterocyclic ring, X ² is a cyclic ether group or a polymerizable unsaturated group; m is 0 or 1, n is 1 An integer of ~3; wherein, when n=3, m=0; in the case where n is 2 or 3, a plurality of R ² and X ¹ may be the same or different from each other, in the case of (3-nm)=2. Next, a plurality of R ³ and X ² may be the same as or different from each other).

In another aspect, the present invention provides a liquid crystal alignment film formed using the liquid crystal alignment agent. Further, the present invention provides a liquid crystal display element including the liquid crystal alignment film.

According to the liquid crystal alignment agent of the present invention, it is possible to obtain a highly reliable liquid crystal alignment film which exhibits excellent characteristics (for example, electrical characteristics) even under a severe use environment. Further, since the liquid crystal display element of the present invention has the liquid crystal alignment film formed using the liquid crystal alignment agent of the present invention, it is less in display quality and excellent in reliability when used in a severe environment.

The liquid crystal alignment agent of the present invention contains at least one polymer (A) selected from the group consisting of polylysine, polyphthalate, and polyimine, and a specific nitrogen-containing compound. Hereinafter, each component contained in the liquid crystal alignment agent of the present invention and, if necessary, The other ingredients that are arbitrarily formulated are explained.

<Polymer (A): Polylysine>

The polyproline which is the polymer (A) of the present invention can be obtained by reacting a tetracarboxylic dianhydride with a diamine.

[tetracarboxylic dianhydride]

Examples of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid of the present invention include aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride. Specific examples of the tetracarboxylic dianhydride include aliphatic tetracarboxylic dianhydride, for example, 1,2,3,4-butanetetracarboxylic dianhydride, and the like; for example, an alicyclic tetracarboxylic dianhydride can be mentioned. Out: 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5 -(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-six Hydrogen-8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[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- Furyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6- Anhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, 4,9-dioxatricyclo[5.3.1.02,6]11 Examples of the alkane-3,5,8,10-tetraketone, cyclohexanetetracarboxylic dianhydride, and the like; and the aromatic tetracarboxylic dianhydride may, for example, be pyromellitic dianhydride or the like; in addition, a Japanese patent may be used. The tetracarboxylic dianhydride disclosed in Japanese Laid-Open Patent Publication No. 2010-97188. Further, the tetracarboxylic dianhydride may be used alone or in combination of two or more.

The tetracarboxylic dianhydride used in the synthesis preferably contains an alicyclic tetracarboxylic dianhydride from the viewpoints of transparency, solubility in a solvent, and the like. Alicyclic tetracarboxylic acid Among the acid dianhydrides, it is preferred to contain a compound selected from the group consisting of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5). -dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-methyl-5 -(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3 .0] at least one selected from the group consisting of octane-2:4,6:8-dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride, more preferably comprising 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride and 1,2,3 At least one of the group consisting of 4-cyclobutanetetracarboxylic dianhydride (hereinafter also referred to as a specific tetracarboxylic dianhydride).

In the case where the specific tetracarboxylic dianhydride is included as the tetracarboxylic dianhydride used in the synthesis, the total content of these compounds relative to the total amount of the tetracarboxylic dianhydride used in the synthesis of the polyamic acid It is preferably 10 mol% or more, more preferably 20 mol% to 100 mol%, still more preferably 50 mol% to 100 mol%.

[diamine]

Examples of the diamine used for the synthesis of the poly-proline of the present invention include aliphatic diamines, alicyclic diamines, aromatic diamines, and diamine-based organodecanes. Specific examples of the diamine include aliphatic m-diamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, and hexamethylenediamine. Examples of the alicyclic diamine include 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and 1,3-bis(aminomethyl). Cyclohexane or the like; examples of the aromatic diamine include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 1,5- Diaminonaphthalene, 2,2'-dimethyl-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) hydrazine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4 , 4'-(p-phenylenediisopropylidene)diphenylamine, 4,4'-(m-phenylenediisopropylidene)diphenylamine, 1,4-bis(4-aminophenoxyl) Benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3, 6-diaminoacridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N,N'- Bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, 1,4-bis-(4-amino group Phenyl)-piperazine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indole-5-amine, 1-(4-amino group Phenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indol-6-amine, 3,5-diaminobenzoic acid, cholestyloxy-3,5-di Cholestanyloxy-3,5-diaminobenzene, cholesteneoxy-3,5-diaminobenzene, cholestyloxy-2,4-diaminobenzene, cholesteneoxy-2 , 4-diaminobenzene, cholesteryl 3,5-diaminobenzoic acid, cholesteryl 3,5-diaminobenzoic acid, 3,5-diaminobenzoic acid lanostane Base ester, 3,6-bis(4-aminobenzylideneoxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethyl Oxybenzophenoxy)cyclohexyl-3,5-diaminobenzoate, 4-(4'-trifluoromethylbenzyloxy)cyclohexyl-3,5-diaminobenzene Formate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 1,1-bis(4-((aminophenyl)) Phenyl)-4-heptyl ring Hexane, 1,1-bis(4-((aminophenoxy)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenyl)) Phenyl)-4-(4-heptylcyclohexyl)cyclohexane, 2,4-diamino-N,N-diallylaniline, 4-aminobenzylamine, 3-amino Benzylamine, 1,3-diamino-4-octadecyloxybenzene, 3-(3,5-diaminobenzylideneoxy)cholane, 3,6-bis(4-amine a benzylidene oxy) cholestane, a compound represented by the following formula (D-1), etc. [Chemical 2]

(In the formula (D-1), X ^I and X ^II are each independently a single bond, -O-, -COO- or -OCO-, and R ^I and R ^II are each independently an alkanediyl group having 1 to 3 carbon atoms. a is 0 or 1, b is an integer of 0 to 2, c is an integer of 1 to 20, and n is 0 or 1. Among them, a and b are not 0), and a diamine-based organodecane can be exemplified. In addition to the 1,3-bis(3-aminopropyl)-tetramethyldioxane, a diamine disclosed in Japanese Laid-Open Patent Publication No. 2010-97188 can be used.

The divalent group represented by "-X ^I -(R ^I -X ^II ) _n -" in the formula (D-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 group "-C _c H _2c+1 " include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, and n-octyl group. N-decyl, n-decyl, 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 other groups.

Specific examples of the compound represented by the formula (D-1) include a compound represented by the following formula (D-1-1) to formula (D-1-5).

[Chemical 3]

Further, these diamines may be used alone or in combination of two or more.

The diamine used in the synthesis of the polyproline of the present invention preferably contains 30 mol% or more of an aromatic diamine relative to all diamines, more preferably 50 mol% or more of an aromatic diamine, and further preferably Contains 80 mol% or more of an aromatic diamine.

[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 a tetracarboxylic dianhydride and a diamine as described above. By setting the polymer of the terminal modification type, 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 molecular weight modifiers include, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl group. Succinic anhydride, n-hexadecyl succinic anhydride, etc.; monoamine compounds include, for example, aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-dodecyl An amine, n-octadecylamine or the like; a monoisocyanate compound may, for example, be phenyl isocyanate or naphthyl isocyanate. Wait.

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 amount of the tetracarboxylic dianhydride and the diamine to be used.

<Synthesis of polylysine>

With respect to the use ratio of the tetracarboxylic dianhydride to the diamine in the synthesis reaction of the polyaminic acid to be used in the present invention, it is preferred that the acid anhydride group of the tetracarboxylic dianhydride becomes 0.2 equivalent to the amine group of the diamine. More preferably, the ratio of the equivalent to 2 equivalents is that the acid anhydride group of the tetracarboxylic dianhydride is in a ratio of 0.3 equivalent to 1.2 equivalent. Further, the synthesis reaction of polyproline is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20 ° C to 150 ° C, 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 used in the reaction include an aprotic polar solvent, a phenol solvent, an alcohol, a ketone, an ester, an ether, a halogenated hydrocarbon, and a hydrocarbon.

Specific examples of such an organic solvent include an aprotic polar solvent: N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone (1,3-dimethyl-2-imidazolidinone). ), N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl hydrazine, γ-butyrolactone, tetramethylurea, Examples of the phenol-based solvent include phenol, m-cresol, xylenol, and halogenated phenol; and examples of the alcohol include methanol, ethanol, and the like. Propyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, etc.; ketones include, for example, acetone, methyl ethyl ketone, methyl Isobutyl ketone, cyclohexanone, etc.; esters such as For example: ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate , isoamyl propionate, isoamyl isobutyrate, etc.; ethers, for example, diethyl ether, ethylene glycol methyl ether, ethylene glycol ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene two Alcohol 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, two Ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, diisoamyl ether, etc.; halogenated hydrocarbons include, for example, dichloromethane, 1,2-dichloroethane, 1, 4-Dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, etc.; examples of the hydrocarbons include hexane, heptane, octane, benzene, toluene, xylene, and the like.

Among these organic solvents, it is preferred to use one or more selected from the group consisting of an aprotic polar solvent and a phenolic solvent (the first group of organic solvents), or selected from the first group of organic solvents. One or more 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 ratio of the organic solvent of the second group is preferably 50% by weight or less, more preferably 40% by weight or less, based on the total amount of the organic solvent of the first group and the organic solvent of the second group. It is preferably 30% by weight or less.

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

As described above, a reaction solution obtained by dissolving polylysine can be obtained. The reaction solution can be directly used for preparing a liquid crystal alignment agent, or can be reacted The polylysine contained in the solution is separated and supplied to prepare a liquid crystal alignment agent, or the separated polyamic acid may be purified and then supplied to prepare a liquid crystal alignment agent. In the case where polylysine is dehydrated and closed 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 separated and then subjected to dehydration. The ring closure reaction, or the isolated polyamic acid can also be purified for dehydration ring closure reaction. The separation and purification of polylysine can be carried out according to well-known methods.

<Polymer (A): Polyamide)

The polyglycolate which is the polymer (A) of the present invention can be obtained, for example, by the following method: [I] esterification of the polyamic acid obtained by the synthesis reaction using a hydroxyl group-containing compound or an ether compound a method for synthesizing a polyphthalate ester; [II] a method for reacting a tetracarboxylic acid diester dichloride with a diamine; [III] a method for reacting a tetracarboxylic acid diester with a diamine. Further, the polyperurate may have only a phthalate structure, or may be a partial ester compound in which a valeric acid structure and a phthalate structure coexist.

<Polymer (A): Polyimine)

The polyimine which is the polymer (A) contained in the liquid crystal alignment agent of the present invention can be obtained by dehydrating a poly-proline which is synthesized as described above and subjecting it to imidization.

The polyimine may be a complete hydrazine imide formed by dehydration ring closure of all of the lysine structures possessed by the polyamic acid as a precursor thereof, or may be a closed loop of only a part of the proline structure. The partial ruthenium imide of the proline structure and the quinone ring structure. From the viewpoint of improving the voltage holding ratio, the polyimine of the present invention preferably has a sulfhydrylation ratio of 30% or more, more preferably 40% to 99%, still more preferably 50% to 99%. The sulfhydrylation rate is expressed as a percentage of the number of quinone ring structures in the polyimine structure and the quinone ring structure. The proportion of the total number of the total. Here, a part of the quinone ring may also be an isoindole ring.

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

In the method of adding a dehydrating agent and a dehydration ring-closure catalyst to a solution of a polyamic acid to carry out hydrazine imidation, an acid anhydride such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride can be used as the dehydrating agent. The amount of the dehydrating agent used is preferably set to 0.01 mol to 20 mol relative to the proline structure of poly-proline. As the dehydration ring-closing catalyst, for example, a tertiary amine such as pyridine, collidine, lutidine or triethylamine can be used. The amount of the dehydration ring-closing catalyst to be used is preferably set to 0.01 mol to 10 mol with respect to the dehydrating agent used. The organic solvent used in the dehydration ring-closure reaction may, for example, be an organic solvent exemplified as an 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.

Thus, a reaction solution containing polyimine can be obtained. The reaction solution may be directly used for preparing a liquid crystal alignment agent, or may be used for preparing a liquid crystal alignment agent after removing a dehydrating agent and a dehydration ring-closing catalyst from the reaction solution, or may be used for preparing a liquid crystal alignment agent after separating the polyfluorene imide, or The isolated polyimine can also be purified and used to prepare a liquid crystal alignment agent. These purification operations can be carried out in accordance with well-known methods.

<Solid viscosity and weight average molecular weight of polymer (A)>

The polylysine, polyphthalate and polyimine obtained as above are preferably 10 mPa when they are made into a solution having a concentration of 10% by weight. s~800mPa. The solution viscosity of s is more preferably 15 mPa. s~500mPa. s solution viscosity. Further, the solution viscosity (mPa.s) of the polymer is prepared by using an E-type rotational viscometer for a good solvent (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) using the polymer. The concentration of the 10% by weight polymer solution was measured at 25 ° C. Further, the poly-proline, polyphthalate, and polyimine contained in the liquid crystal alignment agent of the present invention are converted to polystyrene by gel permeation chromatography (GPC). The weight average molecular weight (Mw) is preferably from 500 to 100,000, more preferably from 1,000 to 50,000.

<compound (B)>

The compound (B) contained in the liquid crystal alignment agent of the present invention is a compound having a nitrogen-containing aromatic heterocyclic ring, specifically, represented by the above formula (1).

R ¹ in the formula (1) is a hydrogen atom, or a one having a chain hydrocarbon group or an alicyclic hydrocarbon group and bonded by a chain hydrocarbon group or an alicyclic hydrocarbon group to a nitrogen atom to which R ² and R ³ are bonded. The price is organic. Such a monovalent organic group, for example, in addition to a monovalent chain hydrocarbon group and a monovalent alicyclic hydrocarbon group, may have a -O bond between a carbon-carbon bond in a monovalent chain hydrocarbon group or a monovalent alicyclic hydrocarbon group. -, -NH-, -CO-O-, -CO-NH-, -CO-, -S-, -S(O) ₂ -, -Si(CH ₃ ) ₂ -, -O-Si (CH ₃ a monovalent group such as an aromatic hydrocarbon group such as ₂ -, -O-Si(CH ₃ ) ₂ -O-, a phenyl group, or a heterocyclic group such as a pyridyl group; a monovalent chain hydrocarbon group or a monovalent alicyclic hydrocarbon group; At least one of the hydrogen atoms is a monovalent group substituted with a fluorine atom, a halogen atom such as a chlorine atom, a bromine atom or an iodine atom, an aromatic hydrocarbon group such as a phenyl group, a hydroxyl group, a halogenated alkyl group or the like.

In addition, the term "chain hydrocarbon group" as used herein means that the main chain does not contain a ring. A saturated hydrocarbon group and an unsaturated hydrocarbon group which are composed only of a chain structure. These include both linear and branched hydrocarbon groups. Further, the alicyclic hydrocarbon group means a structure in which the ring structure contains only an alicyclic hydrocarbon and a hydrocarbon group which does not contain an aromatic ring structure. Among them, it is not necessary to be composed only of the structure of the alicyclic hydrocarbon, and also includes a hydrocarbon group partially having a chain structure.

Specific examples of the monovalent chain hydrocarbon group of R ¹ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, a decyl group, and an undecane group. , dodecyl, tridecyl, tetradecyl, pentadecyl, octadecyl, eicosyl, vinyl, propenyl, butenyl, pentenyl, ethynyl, C Propynyl group and the like. Further, specific examples of the monovalent alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclopentylmethyl group, a cyclohexyl group, a cyclohexylmethyl group, a cyclohexenyl group, and a ring. Heptyl, cyclooctyl, cyclodecyl, cyclodecyl, cycloundecyl, cyclododecyl, cyclotridecyl, cyclotetradecyl, cyclopentadecyl, cyclooctadecyl , cycloecosyl, dicyclohexyl, decahydronaphthyl, norbornyl, methylnorbornyl, adamantyl and the like.

The monovalent organic group of R ¹ preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, still more preferably 1 to 10 carbon atoms.

R ² and R ³ in the formula (1) are a chain hydrocarbon group or an alicyclic hydrocarbon group, and are a chain hydrocarbon group, an alicyclic hydrocarbon group or *-CO-R ⁴ - (wherein R ⁴ is a divalent group) chain hydrocarbon group or an alicyclic hydrocarbon group, and * represents a nitrogen atom bonded by R ¹ is a bond) with a divalent organic group bonded to the nitrogen ^atom, R ¹ are bonded. Examples of the divalent organic group of R ² and R ³ include a divalent chain hydrocarbon group, a divalent alicyclic hydrocarbon group, and *-CO-R ⁴ -. Further, the divalent organic group may also be a divalent group having -O-, -NH-, -CO-O- between a carbon-carbon bond in a divalent chain hydrocarbon group or a divalent alicyclic hydrocarbon group. , -CO-NH-, -CO-, -S-, -S(O) ₂ -, -Si(CH ₃ ) ₂ -, -O-Si(CH ₃ ) ₂ -, -O-Si (CH ₃ a divalent group such as an aromatic hydrocarbon group such as ₂ -O-, a phenyl group, or a heterocyclic group such as pyridinylene; at least one hydrogen atom in the divalent chain hydrocarbon group or the divalent alicyclic hydrocarbon group is subjected to fluorine A halogen atom such as an atom, a chlorine atom, a bromine atom or an iodine atom, an aromatic hydrocarbon group such as a phenyl group, a divalent group substituted with a hydroxyl group or a halogenated alkyl group, or the like. Further, R ² and R ^{3 in the} molecule may be the same as or different from each other.

Specifically, examples of the divalent chain hydrocarbon group of R ² , R ³ and R ⁴ include a methylene group, an exoethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group. Extending octyl group, stretching thiol group, stretching sulfhydryl group, stretching undecyl group, stretching dodecyl group, stretching tridecyl group, stretching tetradecyl group, stretching pentadecyl group, stretching octadecyl group, stretching two a decyl group, a vinyl group, a propylene group, a butyl group, a pentenyl group, an ethynyl group, a propynyl group, etc.; and a divalent alicyclic hydrocarbon group, for example, a propyl group and a ring. Butyl, cyclopentyl, cyclohexyl, cyclohexenylene, cycloheptyl, cyclooctyl, fluorenyl, fluorenyl, undecyl, cyclodecane Base, Cyclotridecyl, Cyclotetradecyl, Cyclopentadecyl, Cyclodecyl, Cyclodecyl, Dicyclohexyl, borneyl, and adamantyl Wait.

The divalent organic group of R ² and R ³ preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, still more preferably 1 to 10 carbon atoms, and particularly preferably 1 to 5 carbon atoms. Further, in the case where a plurality of R ² are present in the formula (1), these R ² may be the same or different from each other, and in the case where a plurality of R ³ are present, these R ³ may be the same or different from each other.

X ¹ in the formula (1) is a nitrogen-containing aromatic heterocyclic ring bonded to a nitrogen atom (a nitrogen atom bonded to R ¹ ) via R ² . The nitrogen-containing aromatic heterocyclic ring may be an aromatic ring containing one or more nitrogen atoms in the ring skeleton. Therefore, the ring skeleton may contain only a nitrogen atom as a hetero atom, or may contain a hetero atom (such as an oxygen atom or a sulfur atom) other than a nitrogen atom and a nitrogen atom. Specific examples of the nitrogen-containing aromatic heterocyclic ring of X ¹ include a pyrrole ring, an imidazole ring, a pyrazole ring, a triazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, and an anthracene ring. , benzimidazole ring, anthracene ring, quinoline ring, isoquinoline ring, naphthyridine ring, quinoxaline ring, phthalazine ring, triazine ring, nitrogen ring (azepine ring), diazonium ring, acridine ring, phenazine ring, phenanthroline ring, oxazole ring, thiazole ring, indazole ring, thiadiazole ring, benzothiazole ring , phenothiazine ring (phenothiazine ring), oxadiazole ring and the like. Further, X ¹ may be a ring in which a substituent is introduced to a carbon atom constituting the ring of the above-exemplified ring. Examples of the substituent include a halogen atom and a monovalent organic group having 1 to 20 carbon atoms. Further, specific examples of the monovalent organic group include the groups exemplified as the monovalent organic group of R ¹ .

In these rings, X ¹ is preferably a ring skeleton of a pyrrole ring, an imidazole ring, a pyrazole ring, a triazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a benzimidazole ring, a naphthyridine ring, or an anthracene. a pyrazine ring, a quinoxaline ring, a triazine ring, a nitrogen anthracene ring, a diazepine ring or a phenazine ring, more preferably a pyrrole ring, an imidazole ring, a pyrazole ring, a triazole ring, a pyridine ring, a pyrimidine ring or a pyridazine ring. Or pyrazine ring.

Further, the bonding position of the nitrogen-containing aromatic heterocyclic ring to R ² is not particularly limited. For example, when the nitrogen-containing aromatic heterocyclic ring as X ¹ is a 5-membered ring, it can be set to 1-position, 2-position or 3-position, and in the case of a 6-membered ring, it can be set to 1-position. , 2-bit, 3-bit or 4-position. In the case where n is 2 or 3, a plurality of X ^{1 are} independent and have the definition.

X ² in the formula (1) is a cyclic ether group or a polymerizable unsaturated group. The cyclic ether group is preferably an epoxy group (oxocyclopropyl) or an oxetanyl group, and more preferably an epoxy group. Further, the polymerizable unsaturated group may have a carbon-carbon double bond, and specifically, a propylene methoxy group, a methacryloxy group, a vinyl group, a vinyloxy group, a maleimide group or a styrene is preferable. base.

Preferable specific examples of the compound (B) include a compound represented by the following formula (1-1), a compound represented by the following formula (1-2), and a compound represented by the following formula (1-3). Wait.

(In the formula (1-1), R ⁵ is a divalent chain hydrocarbon group or an alicyclic hydrocarbon group, and t is 0 or 1. R ¹ and X ¹ have the same meanings as the above formula (1))

(In the formula (1-2), R ⁶ and R ⁷ are each independently a divalent chain hydrocarbon group or an alicyclic hydrocarbon group, and r is 1 or ^2. X ¹ and X ² are respectively the same as the above formula (1) meaning)

(In the formula (1-3), R ⁸ is a divalent organic group bonded to -CO- by a chain hydrocarbon group or an alicyclic hydrocarbon group. R ² and X ¹ have the same meanings as the above formula (1))

With respect to the compound represented by the formula (1-1), R ¹ is preferably a hydrogen atom, a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 10 carbon atoms, more preferably a hydrogen atom or The monovalent chain hydrocarbon group having 1 to 5 carbon atoms is particularly preferably a hydrogen atom. R ⁵ is preferably a divalent chain hydrocarbon group having 1 to 10 carbon atoms or a divalent alicyclic hydrocarbon group having 3 to 10 carbon atoms, more preferably a divalent chain hydrocarbon group having 1 to 10 carbon atoms, particularly preferably 1 to 5 carbon atoms. A divalent chain hydrocarbon group. Further, a preferred specific example of X ¹ can be applied to the description of a preferred specific example of X ¹ of the above formula (1).

t is 0 or 1, and 0 is preferable from the viewpoint of obtaining a liquid crystal alignment film having a less deteriorated degree in a severe use environment.

On the other hand, in the compound represented by the formula (1-2), R ⁶ and R ^{7 are} preferably a divalent chain hydrocarbon group having 1 to 10 carbon atoms or a divalent alicyclic hydrocarbon group having 3 to 10 carbon atoms. A chain hydrocarbon group having 1 to 10 carbon atoms is preferable, and a chain hydrocarbon group having 1 to 5 carbon atoms is particularly preferable. Further, R ⁶ and R ^{7 in the} molecule may be the same as or different from each other. A preferred specific example of X ¹ can be applied to the description of a preferred specific example of X ¹ of the above formula (1). Further, X ² is preferably an epoxy group, an acryloxy group, a methacryloxy group, a vinyl group, a vinyloxy group, a maleimide group or a styryl group, and an epoxy group is particularly preferable.

r is 1 or 2, preferably 2.

In addition, as the compound represented by the formula (1-3), the divalent organic group of R ⁸ may be a group exemplified as a specific example of R ² and R ³ in the formula (1). The number of carbon atoms is preferably from 1 to 19, and more preferably from 1 to 9. R ² is preferably a divalent chain hydrocarbon group having 1 to 10 carbon atoms or a divalent alicyclic hydrocarbon group having 3 to 10 carbon atoms, more preferably a divalent chain hydrocarbon group having 1 to 10 carbon atoms, particularly preferably 1 to 5 carbon atoms. A divalent chain hydrocarbon group. A preferred specific example of X ¹ can be applied to the description of a preferred specific example of X ¹ of the above formula (1). Further, a plurality of X ¹ in the formula (1-3) may be the same as or different from each other.

The compound (B) is preferably selected from the group consisting of the compound represented by the formula (1-1), from the viewpoint of obtaining a liquid crystal alignment film having a very small degree of deterioration even in a severe use environment. (1-2) At least one of the group consisting of the compound represented by the formula and the compound represented by the formula (1-3). Among these compounds, the compound represented by the formula (1-1) is particularly preferable.

Specific examples of the compound (B) contained in the liquid crystal alignment agent of the present invention include compounds represented by the following formulas (ma-1) to (ma-39). Further, in the following formula, the formula (ma-1) to the formula (ma-19) corresponds to a specific example of the compound represented by the formula (1-1), and the formula (ma-26) to the formula (ma-39) Specific examples of the compound represented by the formula (1-2), and the formula (ma-20) to the formula (ma-25) correspond to the compound represented by the formula (1-3). The compound (B) may be used alone or in combination of two or more.

[Chemistry 7]

The compounding ratio of the compound (B) is preferably from 0.1 part by weight to 30 parts by weight based on 100 parts by weight of the total amount of the polymer contained in the liquid crystal alignment agent. By setting the compounding ratio of the compound (B) to 0.1 part by weight or more, the following effects can be suitably obtained: a highly reliable liquid crystal alignment film capable of maintaining a voltage holding ratio even in a severe use environment can be obtained by using a compound The blending ratio of (B) is set to 30 parts by weight or less, and the mechanical strength or electrical properties of the liquid crystal alignment film can be prevented. The compounding ratio of the compound (B) is more preferably 0.5 parts by weight to 25 parts by weight, still more preferably 1.0 parts by weight to 20 parts by weight.

<Other ingredients>

The liquid crystal alignment agent of the present invention may contain other components as needed. The other For example, a polymer other than the polymer (A) or a compound having at least one epoxy group in the molecule (excluding a compound corresponding to the compound (B)) may be mentioned. An epoxy group-containing compound"), a functional decane compound, and the like.

<Other polymers>

The other polymers can be used to improve solution properties or electrical properties. Examples of the other polymer include polyorganosiloxane, polyester, polyamine, cellulose derivative, polyacetal, polystyrene derivative, and poly(styrene-phenylmaleimide). Derivatives, poly(meth)acrylates, and the like.

In the case where the other polymer is added to the liquid crystal alignment agent, the compounding ratio of the other polymer is preferably 50 parts by weight or less, more preferably 0.1 part by weight, based on 100 parts by weight of the total amount of the polymer contained in the liquid crystal alignment agent. ~40 parts by weight, further preferably 0.1 parts by weight to 30 parts by weight.

<epoxy group-containing compound>

The epoxy group-containing compound can be used to improve the adhesion or electrical properties of the liquid crystal alignment film to the surface of the substrate. Examples of such an epoxy group-containing compound include the following compounds as preferred compounds: ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and polypropylene glycol. Diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromopentane 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- Aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine and the like. Other than that, As the epoxy group-containing compound, an epoxy group-containing polyorganosiloxane having the disclosure of WO 2009/096598 can be used.

In the case where the epoxy compound is added to the liquid crystal alignment agent, the compounding ratio of these epoxy compounds is preferably 40 parts by weight or less, more preferably 0.1% by weight based on 100 parts by weight of the total amount of the polymer contained in the liquid crystal alignment agent. Parts by weight to 30 parts by weight.

<Functional decane compound>

The functional decane compound can be used in order 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-aminopropylpropane. Triethoxy decane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyl dimethyl Oxydecane, 3-ureidopropyltrimethoxydecane, 3-ureidopropyltriethoxydecane, N-ethoxycarbonyl-3-aminopropyltrimethoxydecane, N-III Ethoxy decyl propyl triethylene triamine, 10-trimethoxy decyl-1,4,7-triazadecane, 9-trimethoxydecyl-3,6-diazaindole Acid ester, methyl 9-trimethoxydecyl-3,6-diazadecanoate, N-benzyl-3-aminopropyltrimethoxydecane, N-phenyl-3-aminopropyl Trimethoxy decane, glycidoxymethyl trimethoxy decane, 2-glycidoxyethyl trimethoxy decane, 3-glycidoxy propyl trimethoxy decane, and the like.

In the case where the functional decane compound is added to the liquid crystal alignment agent, the compounding ratio of these functional decane compounds is preferably 2 parts by weight or less, based on 100 parts by weight of the total amount of the polymer contained in the liquid crystal alignment agent. It is preferably 0.02 parts by weight to 0.2 parts by weight.

Further, as the other component, in addition to the compound, a compound having at least one oxetanyl group in the molecule, an antioxidant, or the like can be used.

<solvent>

The liquid crystal alignment agent of the present invention is preferably composed of the polymer (A) and the compound (B) and, if necessary, other components which are optionally formulated in an organic solvent.

Here, examples of the solvent for preparing the liquid crystal alignment agent of the present invention include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactone, and N,N-dimethylformamide. , N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, B Ethyl oxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, B Glycol ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethyl Glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisoamyl ether, ethyl carbonate, propyl carbonate, and the like. These solvents may be used alone or in combination of two or more.

The solid content concentration of the liquid crystal alignment agent of the present invention (the ratio of the total weight of the components other than the solvent of the liquid crystal alignment agent to the total weight of the liquid crystal alignment agent) can be appropriately selected in consideration of viscosity, volatility, etc., and preferably 1 weight. Range of %~10% by weight. In other words, the liquid crystal alignment agent of the present invention is applied to the surface of the substrate as described below, and is preferably formed by heating to form a coating film as a liquid crystal alignment film or a coating film to be a liquid crystal alignment film. When it is less than 1% by weight, the film thickness of the coating film becomes too small, and it is difficult to obtain a favorable 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, and a favorable liquid crystal alignment film cannot be obtained, and the viscosity of the liquid crystal alignment agent increases, and the coating property deteriorates.

A particularly preferable range of the solid content concentration differs depending on the method used when the liquid crystal alignment agent is coated on the substrate. For example, in the case of using the rotator method, it is particularly preferable that the solid content concentration is 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 concentration to a range of 3% by weight to 9% by weight, thereby setting the solution viscosity to 12 mPa. s~50mPa. The scope of s. In the case of using the inkjet method, it is particularly preferable to set the solid content concentration to a range of 1% by weight to 5% by weight, thereby setting the solution viscosity to 3 mPa. s~15mPa. 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 100 ° C, more preferably from 20 ° C to 80 ° C. Further, when the polymer (A) and the compound (B) are mixed, the compound (B) may be directly added to the polymer solution in which the polymer (A) is dissolved, but it is preferred to dissolve the compound (B) in an appropriate amount. After the solvent (for example, a solvent which can dissolve the polymer (A)), the solution is mixed with the polymer solution.

<Liquid alignment film and liquid crystal display element>

The liquid crystal alignment film of the present invention is formed using 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 driving mode of the liquid crystal display element to which the present invention is applied is not particularly limited, and can be applied to TN type, STN type, IPS type, FFS type, VA type, multi-domain vertical alignment (MVA) type, PSA type, and the like. In various drive modes.

The liquid crystal display element of the present invention can be produced, for example, by the following steps (1) to (3). In the step (1), the use of the substrate differs depending on the driving mode required. Step (2) and step (3) are the same in each drive 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, VA type, MVA type or PSA type liquid crystal display element, two substrates provided with a patterned transparent conductive film are used as a pair of substrates, The surface on which the transparent conductive film is formed on each of the substrates is preferably coated with the liquid crystal alignment agent of the present invention by an offset printing method, a spin coating method, a roll coater method or an inkjet printing method. 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 may be used. A transparent substrate of plastic such as poly(alicyclic olefin). The transparent conductive film provided on one surface of the substrate may be a Neisser (NESA) film containing tin oxide (SnO ₂ ) (registered trademark of PPG, USA), and containing indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ). Indium Tin Oxide (ITO) film or the like. 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 having no pattern, and a mask having a desired pattern when forming a transparent conductive film may be used. (mask) method, etc. 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 on which the coating film is to be formed on the surface of the substrate may be coated with a functional decane compound or a functional titanium compound. Pre-processing.

After the liquid crystal alignment agent is applied, in order to prevent dripping of the applied alignment agent or the like, it is preferred to carry out preheating (prebaking). The prebaking temperature is preferably 30 ° C to 200 ° C, more preferably 40 ° C to 150 ° C, and particularly preferably 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, in order to completely remove the solvent, and to lysine which is present in the polymer as needed The structure is subjected to thermal imidization and a calcination (post-baking) step is carried out. The calcination temperature (post-baking temperature) at this time is preferably 80 ° C to 300 ° C, more preferably 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. Thus, 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) In the case of manufacturing an IPS type or FFS type liquid crystal display element, an electrode-formed surface of a substrate provided with an electrode including a transparent conductive film or a metal film patterned into a comb-tooth type The liquid crystal alignment agent of the present invention is applied to one surface of the opposite substrate on which the electrode is not provided, and then each coated surface is heated 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 are as described above ( 1-1) 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), after the liquid crystal alignment agent is applied onto the substrate, the organic solvent is removed to form a coating film to be an alignment film. In this case, in the case where the polymer contained in the liquid crystal alignment agent of the present invention is a polyamic acid, a polyphthalate or a ruthenium imidized polymer having a quinone ring structure and a proline structure. It is also possible to carry out a dehydration ring-closure reaction by further heating after forming a coating film to prepare a coating film which is further imidized.

[Step (2): Friction treatment]

In the case of manufacturing a liquid crystal display element of a TN type, an STN type, an IPS type or an FFS type, a rubbing treatment for rubbing a coating film formed in the step (1) in a certain direction by a roll, which is wound on a roll A cloth containing fibers such as nylon, rayon, cotton, and the like. Thereby, the alignment ability of the liquid crystal molecules is imparted to the coating film to become 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 after the rubbing treatment may be further subjected to the following treatment so that the liquid crystal alignment film has different liquid crystal alignment ability depending on the viewing area, that is, the liquid crystal alignment film is irradiated by irradiating a part of the liquid crystal alignment film with ultraviolet rays. The process of changing the pretilt angle of a part of the region; or after forming a resist film on a part of the surface of the liquid crystal alignment film, rubbing treatment in a direction different from the previous rubbing treatment, and then removing the resist film. In this case, the field of view characteristics of the obtained liquid crystal display element can be improved.

In the case of producing a PSA liquid crystal display device, the following step (3) may be carried out by directly using the coating film formed in the above step (1), or may be carried out by a simple method in order to control the tilt of the liquid crystal molecules. The alignment is divided and the weak rubbing treatment is performed.

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

(3-1) Two substrates in which the liquid crystal alignment film was formed as described above were prepared, and liquid crystals were placed between the two substrates arranged in the opposite direction to manufacture a liquid crystal cell. When manufacturing a liquid crystal cell, the following two methods are mentioned, for example. First, the first method is a method that has been known for a long time. In this method, first, the gaps (cell gaps) are left in the liquid crystal alignment film, and the two substrates are arranged to face each other, and the peripheral portions of the two substrates are bonded together using a sealant, and are divided by the surface of the substrate and the sealant. After filling the liquid crystal into the cell gap, the injection hole is sealed, thereby manufacturing a liquid crystal cell. In addition, the second method is a method called a One Drop Fill (ODF) method. In this method, for example, a UV-curable sealing material is applied to a predetermined portion of one of the two substrates on which the liquid crystal alignment film is formed, and further, the liquid crystal alignment is performed. After the liquid crystal is dropped on a predetermined portion of the film surface, the other substrate is bonded in such a manner that the liquid crystal alignment film faces each other. Then, the liquid crystal is pushed and spread over the entire surface of the substrate, and then the entire surface of the substrate is irradiated with ultraviolet light to harden the sealant, thereby manufacturing a liquid crystal cell. In any of the methods, it is preferred that the liquid crystal cell produced as described above is further heated until the liquid crystal used is in the in-phase temperature, and then slowly cooled to room temperature, thereby liquid crystal The flow alignment at the time of filling is removed.

As the sealant, for example, an epoxy resin containing a curing agent and an alumina ball as a spacer can be used. Further, 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, or a phenylcyclohexane can be used. Liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane liquid crystal, cubane liquid crystal, or the like. Further, it is also possible to use a liquid crystal such as cholesteryl chloride, cholesteryl citrate or cholesteryl carbonate in the liquid crystal; for example, the trade names "C-15" and "CB-15" (Merck) A chiral agent sold by the company; a ferroelectric liquid crystal such as p-oxybenzylidene-p-amino-2-methylbutylcinnamate.

(3-2) In the case of producing a PSA type liquid crystal display device, a liquid crystal cell is constructed in the same manner as in the above (3-1) except that a photopolymerizable compound is injected or dropped together with the liquid crystal. Thereafter, the liquid crystal cell is irradiated with light in a state where a voltage is applied between the conductive films of the pair of substrates. The voltage applied here can be set, for example, to 5 V to 50 V DC or AC. Further, as the irradiation light, for example, ultraviolet rays and visible rays containing light having a wavelength of 150 nm to 800 nm can be used, and ultraviolet rays containing light having a wavelength of 300 nm to 400 nm are preferable. As the light source for illuminating light, for example, a low pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser or the like can be used. Further, the ultraviolet light of the preferred wavelength range can be obtained by a method in which a light source is used in combination with, for example, a filter, a diffraction grating, or the like. The irradiation amount of light is preferably 1,000 J/m ² or more and less than 200,000 J/m ² , and more preferably 1,000 J/m ² to 100,000 J/m ² .

Then, a polarizing plate is attached to the outer surface of the liquid crystal cell, whereby the liquid crystal display element of the present invention can be obtained. In the polarizing plate which is bonded to the outer surface of the liquid crystal cell, a polarizing film called "H film" which is obtained by stretching a polyvinyl alcohol to one side and absorbing iodine by using a cellulose acetate protective film is used. A polarizing plate or a polarizing plate containing the H film itself. Further, in the case where the coating film is subjected to the rubbing treatment, the two substrates are arranged such that the rubbing directions of the respective coating films are at a predetermined angle, for example, orthogonal or anti-parallel.

The liquid crystal display element of the present invention can be effectively applied to various devices, for example, can be used for a clock, a handheld game machine, a word processor, a notebook computer, a car navigation system, a camcorder, and a personal digital device. Display devices for assistants (Personal Digital Assistants, PDAs), digital cameras, mobile phones, smart phones, various displays, LCD TVs, etc.

[Examples]

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

In the following examples and comparative examples, the ruthenium imidization ratio of the polyimine in the polymer solution, the solution viscosity of the polymer solution, the weight average molecular weight of the polymer, and the epoxy equivalent were measured by the following methods.

[醯Iminization rate of polyimine]

The solution of polyimine is put into pure water, and the obtained precipitate is sufficiently dried under reduced pressure at room temperature, and then dissolved in deuterated dimethyl hydrazine, and tetramethyl decane is used as a standard substance at room temperature. ¹ H-NMR (Nuclear Magnetic Resonance, NMR) was measured. From the obtained ¹ H-NMR spectrum, the oxime imidization ratio [%] was determined from the following formula (x).

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

(In the formula (x), 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 precursor of the polymer (polyamide) The ratio of the number of other protons of one proton relative to the NH group in the acid)

[Solid viscosity of polymer solution]

Solution viscosity of polymer solution [mPa. s] is a solution prepared by using a predetermined solvent to have a polymer concentration of 10% by weight, which is measured at 25 ° C using an E-type rotational viscometer.

[weight average molecular weight of polymer]

The weight average molecular weight is a value in terms of polystyrene measured by gel permeation chromatography under the following conditions.

Pipe column: manufactured by Tosoh (stock), TSKgelGRCXLII

Solvent: tetrahydrofuran

Temperature: 40 ° C

Pressure: 68kgf/cm ²

[epoxy equivalent]

Epoxy equivalent is based on Japanese industrial standards (Japanese Industrial Standards, JIS) C 2105 describes the hydrochloric acid-methyl ethyl ketone method.

<Synthesis of Polymer (A)>

[Synthesis Example 1: Synthesis of Polyimine (PI-1)]

22.4 g (0.1 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride (TCA) as tetracarboxylic dianhydride, and 8.6 g (0.08 mol) of p-phenylenediamine (PDA) as a diamine 1) g (0.02 mol) of 3,5-diaminobenzoic acid cholesteryl (HCDA) was dissolved in 166 g of N-methyl-2-pyrrolidone (NMP) and reacted at 60 ° C for 6 hours. A solution containing 20% by weight of polylysine was obtained. The obtained polyaminic acid solution was divided into small amounts, and NMP was added to prepare a solution having a polyglycine concentration of 10% by weight and the measured solution viscosity was 90 mPa. s.

Then, NMP was added to the obtained polyamic acid solution to prepare a solution having a polyglycine concentration of 7 wt%, 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 is subjected to solvent replacement using 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), whereby the sulfhydrylation ratio is obtained. About 68% of a solution containing 26% by weight of polyimine (PI-1). The obtained polyimine solution was divided into small amounts, and NMP was added to prepare a solution having a polyimine concentration of 10% by weight and the measured solution viscosity was 45 mPa. s.

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

22.5 g (0.1 mol) of TCA as tetracarboxylic dianhydride, and 10.7 g (0.07 mol), cholestyloxy-2 as 3,5-diaminobenzoic acid (35 DAB) as a diamine. 4-diaminobenzene (HCODA) 7.35 g (0.015 mol) and the compound (LDA) represented by the formula (D-1-5) 6.94 g (0.015 mol) dissolved in NMP 190 g at 60 ° C The reaction was carried out for 6 hours to obtain a polyglycine containing 20% by weight. Solution. The obtained polyaminic acid solution was divided into small amounts, and NMP was added to prepare a solution having a polyglycine concentration of 10% by weight and the measured solution viscosity was 80 mPa. s.

Then, NMP was added to the obtained polyamic acid solution to prepare a solution having a polyamine concentration of 7 wt%, and 15.7 g of pyridine and 20.3 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 using a new NMP, whereby a solution containing 26% by weight of polyimine (PI-2) having a ruthenium iodide ratio of about 80% was obtained. The obtained polyimine solution was divided into small amounts, and NMP was added to prepare a solution having a polyimine concentration of 10% by weight and the measured solution viscosity was 40 mPa. s.

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

2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride (BODA) as a tetracarboxylic dianhydride 18.7 g (0.075 mol) and 1, 2,3,4-cyclobutanetetracarboxylic dianhydride (CB) 4.90 g (0.025 mol), and 35 DAB as a diamine 10.7 g (0.07 mol) and 1,3-diamino-4-{ 4-[trans-4-(trans-4-n-pentylcyclohexyl)cyclohexyl]phenoxy}benzene (PBCH5DAB, a compound represented by the formula (D-1-2)) 13.1 g (0.03) Mohr was dissolved in 190 g of NMP, and reacted at 60 ° C for 6 hours to obtain a solution containing 20% by weight of poly-proline. The obtained polyaminic acid solution was divided into small amounts, and NMP was added to prepare a solution having a polyglycine concentration of 10% by weight and the measured solution viscosity was 85 mPa. s.

Then, NMP was added to the obtained polyamic acid solution to prepare a solution having a polyglycine concentration of 7 wt%, and 9.5 g of pyridine and 12.3 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 using a new NMP, whereby a solution containing 26% by weight of polyimine (PI-3) having a ruthenium iodide ratio of about 65% was obtained. The resulting polyimine solution A small amount was added, and NMP was added to prepare a solution having a polyamidene concentration of 10% by weight and the measured solution viscosity was 45 mPa. s.

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

TCA 110g (0.50 mole) and 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-) as tetracarboxylic dianhydride 3-furyl)naphtho[1,2-c]furan-1,3-dione 160g (0.50 mole), p-phenylenediamine (PDA) as diamine 91g (0.85 mole), 1,3 - bis(3-aminopropyl)tetramethyldioxane 25g (0.10 moles) and 3,6-bis(4-aminobenzylideneoxy)cholestane 25g (0.040 moles), Further, 1.4 g (0.015 mol) of aniline as a monoamine was dissolved in 960 g of NMP, and the reaction was carried out at 60 ° C for 6 hours to obtain a solution containing polyglycine. The obtained polyaminic acid solution was divided into small amounts, and NMP was added to prepare a solution having a polyglycine concentration of 10% by weight and the measured solution viscosity was 60 mPa. s.

Then, 2,700 g of NMP was added to the obtained polyamic acid solution, and 390 g of pyridine and 410 g of acetic anhydride were added, and the 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 using a new γ-butyrolactone, thereby obtaining a polyfluorene imine (PI-4) containing 15% by weight of a ruthenium iodide ratio of about 95%. The solution was about 2,500 g. The solution was divided into small amounts, and NMP was added to prepare a solution having a polyamidene concentration of 10% by weight and the measured solution viscosity was 70 mPa. s.

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

22.4 g (0.1 mol) of TCA as tetracarboxylic dianhydride, and 8.6 g (0.08 mol) of PDA as diamine, 2.0 g (0.01 mol) of 4,4'-diaminodiphenylmethane. And 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl 3.2 g (0.01 mol) was dissolved in NMP 324 g, and reacted at 60 ° C for 4 hours to obtain 10 weight. % solution of polylysine.

Then, 360 g of NMP was added to the obtained polyamic acid solution, and 39.5 g of pyridine and 30.6 g of acetic anhydride were added, and the 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 using a new NMP to obtain a solution containing 10% by weight of polyimine (PI-5) having a ruthenium iodide ratio of about 93%. The obtained polyimine solution was divided into small amounts and the measured solution viscosity was 30 mPa. s.

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

A polyaminic acid solution was obtained by the same method as in the above Synthesis Example 1, except that the diamine used was changed to 35 DAB 12.2 g (0.08 mol) and HCODA 9.8 g (0.02 mol). The obtained polyaminic acid solution was divided into small amounts, and NMP was added to prepare a solution having a polyglycine concentration of 10% by weight and the measured solution viscosity was 80 mPa. s.

Then, the oxime imidization was carried out by the same method as in the above Synthesis Example 1, and a solution containing 26% by weight of polyimine (PI-6) having a ruthenium iodide ratio of about 65% was obtained. The obtained polyimine solution was divided into small amounts, and NMP was added to prepare a solution having a polyimine concentration of 10% by weight and the measured solution viscosity was 40 mPa. s.

[Synthesis Example 7: Synthesis of Polyproline (PA-1)]

200 g (1.0 mol) of CB as tetracarboxylic dianhydride and 210 g (1.0 mol) of 2,2'-dimethyl-4,4'-diaminobiphenyl as diamine were dissolved in NMP 370 g In a mixed solvent of 3,300 g of γ-butyrolactone, the reaction was carried out at 40 ° C for 3 hours to obtain a solution containing 10% by weight of poly-proline (PA-1). The obtained polyaminic acid solution was fractionated and the measured solution viscosity was 160 mPa. s.

[Synthesis Example 8: Synthesis of poly-proline (PA-2)]

The tetracarboxylic dianhydride used was set to pyromellitic dianhydride (PMDA) 196g (0.9 mol) and CB 19.6 g (0.1 mol), and the diamine is set to PDA 0.2 mol and 4,4'-diaminodiphenyl ether (DDE), in addition to The same procedure as in Synthesis Example 7 was carried out to obtain a solution containing 10% by weight of poly-proline (PA-2). The obtained polyamic acid solution was divided into small amounts and the measured solution viscosity was 170 mPa. s.

[Synthesis Example 9: Synthesis of polyorganosiloxane (APS-1)]

In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane (ECETS) and 500 g of methyl isobutyl ketone were added. And 10.0 g of triethylamine, and mixed at room temperature. Then, 100 g of deionized water was added dropwise from the dropping funnel over 30 minutes, and then the reaction was carried out at 80 ° C for 6 hours while stirring under reflux. After completion of the reaction, the organic layer was taken out and washed with a 0.2% by weight aqueous solution of ammonium nitrate until the water after washing became neutral, and then the solvent and water were distilled off under reduced pressure to obtain a viscous transparent liquid. A reactive polyorganosiloxane (EPS-1) is obtained in the form. ¹ H-NMR analysis of the reactive polyorganooxane showed that a theoretically strong epoxy group-based peak was obtained in the vicinity of the chemical shift (δ) = 3.2 ppm, and it was confirmed that no epoxy group was caused in the reaction. side effects. The obtained reactive polyorganosiloxane had a weight average molecular weight Mw of 3,500 and an epoxy equivalent of 180 g/mol.

Then, 10.0 g of a reactive polyorganosiloxane (EPS-1), 30.28 g of methyl isobutyl ketone as a solvent, and 4-dodecyloxybenzoic acid as a reactive compound were placed in a 200 mL three-necked flask. 3.98 g and 0.10 g of UCAT 18X (trade name, manufactured by San-Apro Co., Ltd.) as a catalyst were reacted at 100 ° C for 48 hours under stirring. After the completion of the reaction, ethyl acetate was added to the reaction mixture, and the resulting solution was washed with water three times. After drying the organic layer with magnesium sulfate, the solvent was distilled off to obtain a liquid crystal-aligned polyorganosiloxane (APS-1). ) 9.0g. The obtained polymer had a weight average molecular weight Mw of 9,900.

<Example 1>

[Preparation of Liquid Crystal Aligning Agent]

In the solution containing the polyimine (PI-1) as the polymer (A), 5 parts by weight of the total amount of the polymer is added to give 5 parts by weight of the bis(3-pyridyl group) as the compound (B). A NMP solution of methyl)amine was prepared as a solution having a solvent composition of NMP: BC = 50:50 (weight ratio) and a solid concentration of 6.0% by weight. This solution was filtered using a filter having a pore size of 1 μm, thereby preparing a liquid crystal alignment agent (S1).

[Manufacture of liquid crystal cell]

The prepared liquid crystal alignment agent (S1) was applied onto a transparent electrode surface of a glass substrate with a transparent electrode including an ITO film using a liquid crystal alignment film printer (manufactured by Nippon Photoprint Co., Ltd.) at a heat of 80 ° C The plate was heated (prebaked) for 1 minute to remove the solvent, and then heated (post-baked) on a hot plate at 210 ° C for 30 minutes to form a coating film having an average film thickness of 80 nm.

The coating film was subjected to rubbing treatment under the conditions of a roller rotation speed of 500 rpm, a table moving speed of 3 cm/s, and a hair pressing length of 0.4 mm by using a friction machine having a roller on which the rayon cloth was wound. , to give the liquid crystal alignment ability. Thereafter, ultrasonic cleaning was performed for 1 minute in ultrapure water, followed by drying in a clean oven at 100 ° C for 10 minutes, thereby obtaining a substrate having a liquid crystal alignment film. This operation was repeated to obtain a pair of (two sheets) substrates having a liquid crystal alignment film.

Then, for each of the pair of substrates, an epoxy resin adhesive to which an alumina ball having a diameter of 5.5 μm is applied is coated on the outer edge of the surface having the liquid crystal alignment film, and then the liquid crystal alignment film surface is opposite. a pair of substrates overlapping and crimping, Harden the adhesive. Next, a nematic liquid crystal (MLC-6221 manufactured by Merck Co., Ltd.) 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 prepare a liquid crystal cell.

[Evaluation of Reliability of Liquid Crystal Alignment Film]

The obtained liquid crystal cell was applied with a voltage of 5 V under the conditions of an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio (VHR1) after 167 milliseconds from the release of the application was measured. Then, the liquid crystal cell was allowed to stand in an 80 ° C oven irradiated with a light-emitting diode (LED) lamp for 200 hours, and then allowed to stand at room temperature and naturally cooled to room temperature. After cooling, a voltage of 5 V was applied to the liquid crystal cell under the conditions of an application time of 60 μsec and a pitch of 167 msec, and then the voltage holding ratio (VHR2) after 167 msec after the release of the application was measured. Further, the measuring device was "VHR-1" manufactured by Toyo Corporation (TOYO Corporation). The rate of change (ΔVHR) of VHR at this time was calculated by the following formula (y), and the reliability of the liquid crystal alignment film was evaluated by ΔVHR. In the evaluation, when the ΔVHR is 1% or less, the reliability is "very good (?)", and when ΔVHR is more than 1% and 2% or less, the reliability is "good (○)", and △ is When the VHR is greater than 2%, the reliability is "poor (x)" and evaluated. The results are shown in Table 1 below.

△VHR[%]=(VHR1-VHR2)/(VHR1)×100...(y)

[Table 1]

In Table 1, the "addition amount" of the compound (B) is a compounding ratio [parts by weight] based on 100 parts by weight of the total of the polymer components in the liquid crystal alignment agent. The abbreviations of the compound (B) in Table 1 are as follows.

Bis-AMP: bis(3-pyridylmethyl)amine (the compound represented by the formula (ma-1))

Tri-AMP: tris(3-pyridylmethyl)amine (the compound represented by the formula (ma-14))

Epo-AMP: a compound represented by the formula (ma-26)

Epo-AMPm: a compound represented by the formula (ma-27)

DA-AMP: a compound represented by the formula (ma-20)

DA-AEIm: a compound represented by the formula (ma-21)

NM-AMP: 3-(methylaminomethyl)pyridine

3-AMP: 3-aminomethylpyridine

<Example 2 to Example 13, Comparative Example 1, Comparative Example 2>

A liquid crystal alignment agent (S2) to a liquid crystal alignment agent (S13) were prepared in the same manner as in Example 1 except that the type of the polymer (A) used and the type and amount of the compound (B) were changed as described in Table 1. , liquid crystal alignment agent (R1), liquid crystal alignment agent (R2). Further, the reliability of the liquid crystal alignment film was evaluated in the same manner as in Example 1 for each of the prepared liquid crystal alignment agents. The results of these evaluations are shown in Table 1. Further, in Table 1, for Examples 7 to 9 using two polymers as the polymer (A), the ratio of use of each polymer to the total amount of the polymer used was shown (% by weight) ).

As shown in Table 1, each of Examples 1 to 13 using the liquid crystal alignment agent containing the compound (B) was a voltage retention ratio even after exposure to light irradiation at 80 ° C for a long time (200 hours). The reduction is also small and the reliability is good. In particular, in Examples 1 to 9 in which Bis-AMP or Tri-AMP was used as the compound (B), ΔVHR was 0.6% or less, and the voltage holding ratio due to application of optical stress and thermal stress was extremely low. . On the other hand, in Comparative Example 1 and Comparative Example 2 containing no compound (B), the voltage holding ratio was drastically lowered by the application of optical stress and thermal stress.

Claims (5)

A liquid crystal alignment agent comprising: at least one polymer (A) selected from the group consisting of polylysine, polyphthalate, and polyamidiamine, and the following formula (1) Compound (B) indicated, (In the formula (1), R ¹ is a hydrogen atom or a monovalent organic group bonded with a nitrogen atom bonded to R ² and R ³ by a chain hydrocarbon group or an alicyclic hydrocarbon group; and R ² and R ³ are each independently The ground is a chain hydrocarbon group, an alicyclic hydrocarbon group or *-CO-R ⁴ - (wherein R ⁴ is a divalent chain hydrocarbon group or an alicyclic hydrocarbon group, and * represents a bond bond with a nitrogen atom bonded to R ¹ a divalent organic group bonded to a nitrogen atom to which R ¹ is bonded; X ¹ is a nitrogen-containing aromatic heterocyclic ring, X ² is a cyclic ether group or a polymerizable unsaturated group; m is 0 or 1, n is An integer from 1 to 3; wherein, when n=3, m=0; in the case where n is 2 or 3, a plurality of R ² and X ¹ may be the same or different from each other, and (3-nm)=2 In this case, a plurality of R ³ and X ² may be the same as or different from each other). The liquid crystal alignment agent according to claim 1, wherein the compound (B) is contained in an amount of 0.1 part by weight to 30 parts by weight based on 100 parts by weight of the total amount of the polymer contained in the liquid crystal alignment agent. Parts by weight. The liquid crystal alignment agent according to claim 1 or 2, wherein the polymer (A) is a polymer obtained by a reaction of a tetracarboxylic dianhydride with a diamine, the tetracarboxylic dianhydride Containing from 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 2,4,6,8- At least one of the group consisting of tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride. A liquid crystal alignment film which is formed by using the liquid crystal alignment agent according to any one of claims 1 to 3. A liquid crystal display element comprising the liquid crystal alignment film according to item 4 of the patent application.