JP2014092775A - Liquid crystal orientation agent, liquid crystal orientation film, and liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly reliable liquid crystal orientation film capable of maintaining excellent characteristics even under a severe use environment.SOLUTION: A polymer (A) such as a polyimide, and a compound (B) represented by following formula (1), are included in a liquid crystal orientation agent, where, Ris a hydrogen atom or an univalent organic group bonded to a nitrogen atom through a chain hydrocarbon group or an alicyclic hydrocarbon group, Rand Rare each a divalent organic group bonded to a nitrogen atom through a chain hydrocarbon group, an alicyclic hydrocarbon group or *-CO-R-, Xis a nitrogen-containing aromatic heterocycle, Xis a cyclic ether group or a polymerizable unsaturated group, m is 0 or 1, n is an integer of 1 to 3, and m is 0 when n is 3.

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display element, and more particularly to a liquid crystal aligning agent for producing a liquid crystal aligning film and a liquid crystal display element comprising a liquid crystal aligning film produced using the liquid crystal aligning agent. .

  Conventionally, as a liquid crystal display element, various drive systems having different electrode structures, physical properties of liquid crystal molecules to be used, manufacturing processes, and the like have been developed. For example, TN type, STN type, VA type, in-plane switching type (IPS type) ), Various liquid crystal display elements such as FFS type and PSA type are known. These liquid crystal display elements have a liquid crystal alignment film for aligning liquid crystal molecules. As a material for the liquid crystal alignment film, polyamic acid or polyimide is generally used 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, it is required that the voltage holding ratio is high in the liquid crystal alignment film, that there is little residual charge when voltage is applied, and that the residual charge is quickly relaxed. Yes. In addition, various liquid crystal aligning agents have been proposed in order to satisfy such requirements (for example, see Patent Documents 1 and 2). Patent Document 1 discloses that a liquid crystal aligning agent contains a very small amount of a compound having one tertiary amino group in a molecule together with polyamic acid or polyimide. Further, in Patent Document 2, a liquid crystal aligning agent may contain a specific tertiary amine such as vinylpyridine or N, N-glycidylaniline together with polyamic acid or polyimide in which a part of polyamic acid is imidized. It is disclosed.

  In recent years, liquid crystal display elements are used not only in display terminals such as personal computers as in the past, but also in various applications such as liquid crystal televisions, car navigation systems, mobile phones, smartphones, and information displays. Yes. With such versatility, the liquid crystal display element is assumed to be used in a severer environment than before. Therefore, the liquid crystal alignment film is required to have high reliability capable of withstanding use in a harsh environment, and various liquid crystal alignment agents have been proposed to satisfy such requirements (for example, (See Patent Document 3 or 4). In these Patent Documents 3 and 4, a polyimide having a carboxyl group, one primary amino group and a nitrogen-containing aromatic heterocycle, and the primary amino group is bonded to an aliphatic hydrocarbon group. And a primary amine compound.

Japanese Patent Laid-Open No. 08-76128 JP 09-316200 A International Publication No. 2008/013285 International Publication No. 2009/084665

  The demand for higher performance of liquid crystal display elements is further increased, and the liquid crystal alignment film is required to be better than the conventional one in that it can exhibit good characteristics even under harsh usage environments. ing.

  The present invention has been made in view of the above problems, and a main object thereof is to provide a liquid crystal aligning agent for obtaining a highly reliable liquid crystal aligning film capable of maintaining good characteristics even under severe use environment.

  As a result of intensive studies to achieve the above-described problems of the prior art, the present inventors can solve the above problems by using a liquid crystal aligning agent containing a specific nitrogen-containing compound together with polyamic acid or polyimide. As a result, the present invention has been completed. Specifically, the present invention provides the following liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element.

  In one aspect, the present invention contains at least one polymer (A) selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, and a compound (B) represented by the following formula (1). A liquid crystal aligning agent is provided.

（式（１）中、Ｒ^１は、水素原子であるか又は、Ｒ^２及びＲ^３が結合する窒素原子に対して鎖状炭化水素基若しくは脂環式炭化水素基で結合する１価の有機基であり、Ｒ^２及びＲ^３は、それぞれ独立に、Ｒ^１が結合する窒素原子に対して鎖状炭化水素基、脂環式炭化水素基又は＊−ＣＯ−Ｒ^４−（但し、Ｒ^４は２価の鎖状炭化水素基又は脂環式炭化水素基であり、＊はＲ^１が結合する窒素原子との結合手を示す。）で結合する２価の有機基である。Ｘ^１は、窒素含有芳香族複素環であり、Ｘ^２は、環状エーテル基又は重合性不飽和基である。ｍは０又は１であり、ｎは１〜３の整数である。但し、ｎ＝３のときｍ＝０である。ｎが２又は３の場合、複数のＲ^２及びＸ^１は、互いに同じでも異なってもよく、（３−ｎ−ｍ）＝２の場合、複数のＲ^３及びＸ^２は、互いに同じでも異なってもよい。）

(In the formula (1), R ¹ is a hydrogen atom, or a monovalent organic group bonded to a nitrogen atom to which R ² and R ³ are bonded by a chain hydrocarbon group or an alicyclic hydrocarbon group. R ² and R ³ are each independently a chain hydrocarbon group, alicyclic hydrocarbon group or * —CO—R ⁴ — (where R ^{4 represents} a nitrogen atom to which R ¹ is bonded. Is a divalent chain hydrocarbon group or alicyclic hydrocarbon group, and * is a divalent organic group bonded by a bond to the 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, and n is an integer of 1 to 3, provided that n = 3 when a m = 0 if .n is 2 or 3, a plurality of ^{R 2} and ^{X 1} may be the same or different, (3-n-m) = 2 field , A plurality of ^{R 3} and ^{X 2} may be the same or different.)

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

  According to the liquid crystal aligning agent of the present invention, it is possible to obtain a highly reliable liquid crystal aligning film that can exhibit good characteristics (for example, electrical characteristics) even under severe use environment. In addition, since the liquid crystal display element of the present invention has a liquid crystal alignment film formed using the liquid crystal aligning agent of the present invention, there is little deterioration in display quality even when used in harsh environments, and excellent reliability. ing.

  The liquid crystal aligning agent of this invention contains at least 1 type of polymer (A) chosen from the group which consists of polyamic acid, polyamic acid ester, and a polyimide, and a specific nitrogen-containing compound. Below, each component contained in the liquid crystal aligning agent of this invention and the other component arbitrarily mix | blended as needed are demonstrated.

<Polymer (A): Polyamic acid>
The polyamic acid as the polymer (A) in the present invention can be obtained by reacting tetracarboxylic dianhydride and diamine.

[Tetracarboxylic dianhydride]
Examples of the tetracarboxylic dianhydride used for synthesizing the polyamic acid in the present invention include aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride and the like. Can be mentioned. Specific examples of these are:
Examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride;
Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic 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, 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- No 1,2-dicarboxylic acid 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-3,5,8,10-tetraone, cyclohexanetetracarboxylic dianhydride Etc .;
Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride and the like; respectively, and tetracarboxylic dianhydrides described in JP 2010-97188 A can be used. In addition, the said tetracarboxylic dianhydride can be used individually by 1 type or in combination of 2 or more types.

  The tetracarboxylic dianhydride used for the synthesis preferably contains an alicyclic tetracarboxylic dianhydride from the viewpoint of transparency and solubility in a solvent. Among alicyclic tetracarboxylic dianhydrides, 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] octane-2: 4,6: Preferably, it contains at least one selected from the group consisting of 8-dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 2,3,5-tricarboxycyclopentylacetic acid dianhydride Thing, 2, , 6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride It is more preferable that it contains at least one (hereinafter also referred to as a specific tetracarboxylic dianhydride).

  When the above-mentioned specific tetracarboxylic dianhydride is included as the tetracarboxylic dianhydride used in the synthesis, the total content of these compounds is based on the total amount of tetracarboxylic dianhydride used in the synthesis of the polyamic acid. It is preferably 10 mol% or more, more preferably 20 to 100 mol%, still more preferably 50 to 100 mol%.

[Diamine]
Examples of the diamine used for synthesizing the polyamic acid in the present invention include aliphatic diamine, alicyclic diamine, aromatic diamine, and diaminoorganosiloxane. Specific examples of these diamines include aliphatic diamines such as m-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine and the like;
Examples of alicyclic diamines include 1,4-diaminocyclohexane, 4,4′-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane and the like;

（式（Ｄ−１）中、Ｘ^I及びＸ^IIは、それぞれ独立に、単結合、−Ｏ−、−ＣＯＯ−又は−ＯＣＯ−であり、Ｒ^Ｉ及びＲ^ＩＩは、それぞれ独立に、炭素数１〜３のアルカンジイル基であり、ａは０又は１であり、ｂは０〜２の整数であり、ｃは１〜２０の整数であり、ｎは０又は１である。但し、ａ及びｂが同時に０になることはない。）
で表される化合物などを； Examples of aromatic diamines 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-diaminofluorene, 4,4′-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl ] Propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane 4,4 ′-(p-phenylenediisopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylene Riden) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diamino Pyrimidine, 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-aminophenyl) -piperazine, 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-indene-5-amine, 1- (4-aminophen 2) -2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine, 3,5-diaminobenzoic acid, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3, 5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestenyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate, 3,5-diamino Lanostanyl benzoate, 3,6-bis (4-aminobenzoyloxy) cholestane, 3,6-bis (4-aminophenoxy) cholestane, 4- (4′-trifluoromethoxybenzoyloxy) cyclohexyl-3,5- Diaminobenzoate, 4- (4′-trifluoromethylbenzoyloxy) cyclohexyl-3,5-di Aminobenzoate, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-butylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-heptylcyclohexane, , 1-bis (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, 1,3-diamino-4-octadecyloxybenzene, 3- (3,5-diaminobenzoyloxy) cholestane, 3,6-bis (4-aminobenzoyloxy) cholestane and the following formula (D-1)

(In 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 a carbon number. 1 to 3 alkanediyl groups, 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, provided that a and b is never 0 at the same time.)
A compound represented by:

  Examples of the diaminoorganosiloxane include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane, and the like, and diamines described in JP 2010-97188 A can be used.

Examples of the divalent group represented by “—X ^I — (R ^I —X ^II ) _n —” in the formula (D-1) include an alkanediyl group having 1 to 3 carbon atoms, * —O—, * —COO— or * —O—C ₂ H ₄ —O— (however, a bond marked with “*” is bonded to a diaminophenyl group) is preferred.
Specific examples of the group “—C _c H _{2c + 1} ” include, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group. Group, n-nonyl group, n-decyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group Group, n-eicosyl group and the like. The two amino groups in the diaminophenyl group are preferably in the 2,4-position or 3,5-position with respect to other groups.

なお、これらのジアミンは、１種を単独で又は２種以上を組み合わせて使用することができる。 Specific examples of the compound represented by the formula (D-1) include, for example, compounds represented by the following formulas (D-1-1) to (D-1-5).

In addition, these diamine can be used individually by 1 type or in combination of 2 or more types.

  The diamine used when synthesizing the polyamic acid in the present invention preferably contains an aromatic diamine in an amount of 30 mol% or more, more preferably 50 mol% or more, and more preferably 80 mol% or more. It is further preferable.

[Molecular weight regulator]
When synthesizing a polyamic acid, a terminal-modified polymer may be synthesized using an appropriate molecular weight regulator together with the tetracarboxylic dianhydride and diamine as described above. By using such a terminal-modified polymer, the coating property (printability) of the liquid crystal aligning agent can be further improved without impairing the effects of the present invention.

Examples of molecular weight regulators include acid monoanhydrides, monoamine compounds, monoisocyanate compounds, and the like. Specific examples thereof include acid monoanhydrides such as maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic. Acid anhydrides, n-hexadecyl succinic anhydride, etc .; monoamine compounds such as aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, Examples of the monoisocyanate compound include n-dodecylamine and n-octadecylamine; for example, phenyl isocyanate and naphthyl isocyanate;
The use ratio of the molecular weight regulator is preferably 20 parts by weight or less, and more preferably 10 parts by weight or less with respect to 100 parts by weight of the total of the tetracarboxylic dianhydride and diamine used.

<Synthesis of polyamic acid>
The ratio of the tetracarboxylic dianhydride and the diamine used in the polyamic acid synthesis reaction in the present invention is such that the acid anhydride group of the tetracarboxylic dianhydride is 0. A ratio of 2 to 2 equivalents is preferable, and a ratio of 0.3 to 1.2 equivalents is more preferable. The synthesis reaction of polyamic acid is preferably performed in an organic solvent. The reaction temperature at this time is preferably −20 ° C. to 150 ° C., more preferably 0 to 100 ° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

Here, examples of the organic solvent used in the reaction include aprotic polar solvents, phenol solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like.
Specific examples of these organic solvents include aprotic polar solvents such as N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, N, N- Dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide and the like; phenolic solvents such as phenol, m-cresol, xylenol and halogenated phenol;
Examples of the alcohol include methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, and the like. Examples of the ketone include acetone, methyl ethyl ketone, Methyl isobutyl ketone, cyclohexanone, etc .; as esters, for example, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate, Isoamyl propionate, isoamyl isobutyrate and the like;
Examples of ethers include diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether, ethylene glycol dimethyl ether, and 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, diisopentyl ether and the like;
Examples of the halogenated hydrocarbon include dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, and the like. Examples of the hydrocarbon include hexane, heptane, octane, benzene, Toluene, xylene, etc. can be mentioned respectively.

Among these organic solvents, one or more selected from the group consisting of an aprotic polar solvent and a phenolic solvent (first group of organic solvents), or one or more selected from the first group of organic solvents, It is preferable to use a mixture with one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (second group organic solvent). In the latter case, the use ratio of the second group organic solvent is preferably 50% by weight or less, more preferably 40% by weight with respect to the total amount of the first group organic solvent and the second group organic solvent. % Or less, more preferably 30% by weight or less.
The amount of organic solvent used (a) is such that the total amount (b) of tetracarboxylic dianhydride and diamine is 0.1 to 50% by weight based on the total amount (a + b) of the reaction solution. It is preferable.

  As described above, a reaction solution obtained by dissolving polyamic acid is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid contained in the reaction solution, or the isolated polyamic acid was purified. You may use for preparation of a liquid crystal aligning agent. When polyamic acid is dehydrated and cyclized into a polyimide, the above reaction solution may be directly subjected to dehydration and cyclization reaction, or may be subjected to dehydration and cyclization reaction after isolating the polyamic acid contained in the reaction solution. Alternatively, the isolated polyamic acid may be purified and then subjected to a dehydration ring closure reaction. Isolation and purification of the polyamic acid can be performed according to known methods.

<Polymer (A): Polyamic acid ester>
The polyamic acid ester as the polymer (A) in the present invention is, for example, [I] a method of synthesizing the polyamic acid obtained by the above synthesis reaction by esterification using a hydroxyl group-containing compound or an ether compound, [ II] A method of reacting a tetracarboxylic acid diester dichloride with a diamine, and [III] a method of reacting a tetracarboxylic acid diester with a diamine. The polyamic acid ester may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist.

<Polymer (A): Polyimide>
The polyimide as the polymer (A) contained in the liquid crystal aligning agent of the present invention can be obtained by dehydrating and ring-closing and imidizing the polyamic acid synthesized as described above.

  The polyimide may be a completely imidized product obtained by dehydrating and cyclizing all of the amic acid structure possessed by the polyamic acid that is the precursor, and only a part of the amic acid structure is dehydrated and cyclized, It may be a partially imidized product in which an imide ring structure coexists. The polyimide in the present invention is preferably 30% or more, more preferably 40 to 99%, and still more preferably 50 to 99% in that the voltage holding ratio can be increased. . This imidation ratio represents the ratio of the number of imide ring structures to the total of the number of polyimide amic acid structures and the number of imide ring structures in percentage. Here, a part of the imide ring may be an isoimide ring.

  The polyamic acid is preferably dehydrated and closed by heating the polyamic acid, or by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to the solution, and heating the solution as necessary. . Of these, the latter method is preferred.

  In the method of imidizing a polyamic acid solution by adding a dehydrating agent and a dehydrating ring-closing catalyst, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used as the dehydrating agent. It is preferable that the usage-amount of a dehydrating agent shall be 0.01-20 mol with respect to 1 mol of the amic acid structure of a polyamic acid. As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, triethylamine and the like can be used. It is preferable that the usage-amount of a dehydration ring-closing catalyst shall be 0.01-10 mol with respect to 1 mol of dehydrating agents to be used. Examples of the organic solvent used in the dehydration ring-closing reaction include the organic solvents exemplified as those used for the synthesis of polyamic acid. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C, more preferably 10 to 150 ° C. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

  In this way, a reaction solution containing polyimide is obtained. This reaction solution may be used for the preparation of the liquid crystal aligning agent as it is, may be used for the preparation of the liquid crystal aligning agent after removing the dehydrating agent and the dehydrating ring-closing catalyst from the reaction solution, and the liquid crystal after isolating the polyimide. You may use for preparation of an aligning agent, or you may use for preparation of a liquid crystal aligning agent, after purifying the isolated polyimide. These purification operations can be performed according to known methods.

<Solution viscosity and weight average molecular weight of polymer (A)>
The polyamic acid, polyamic acid ester and polyimide obtained as described above preferably have a solution viscosity of 10 to 800 mPa · s, when this is made into a solution having a concentration of 10% by weight, and 15 to 500 mPa · s. More preferably, it has a solution viscosity of s. In addition, the solution viscosity (mPa · s) of the above polymer is based on a polymer solution having a concentration of 10% by weight prepared using a good solvent for the polymer (eg, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). The value measured at 25 ° C. using an E-type rotational viscometer. Moreover, about the polyamic acid, polyamic acid ester, and polyimide which are contained in the liquid crystal aligning agent of this invention, the weight average molecular weight (Mw) of polystyrene conversion measured by gel permeation chromatography (GPC) is 500-100,000. It is preferable that it is 1,000-50,000.

<Compound (B)>
The compound (B) contained in the liquid crystal aligning agent of this invention is a compound which has a nitrogen-containing aromatic heterocyclic ring, and is specifically represented by the said Formula (1).

R ¹ in the above formula (1) is a hydrogen atom, or has a chain hydrocarbon group or an alicyclic hydrocarbon group, and chain carbonization with respect to the nitrogen atom to which R ² and R ³ are bonded. It is a monovalent organic group bonded through a hydrogen group or an alicyclic hydrocarbon group. Examples of such a monovalent organic group include a monovalent chain hydrocarbon group and a monovalent alicyclic hydrocarbon group, as well as a monovalent chain hydrocarbon group or a monovalent alicyclic carbon group. Between the carbon-carbon bonds in the hydrogen group, —O—, —NH—, —CO—O—, —CO—NH—, —CO—, —S—, —S (O) ₂ —, —Si (CH _{3) 2 -, - O-} Si (CH 3) 2 -, - O-Si (CH 3) 2 -O-, 1 having an aromatic hydrocarbon group, a heterocyclic group such as a pyridinylene group such as a phenylene group A valent group; at least one hydrogen atom in a monovalent chain hydrocarbon group or monovalent alicyclic hydrocarbon group is a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom; And monovalent groups substituted with an aromatic hydrocarbon group, a hydroxyl group, a halogenated alkyl group, and the like.

  In addition, the chain hydrocarbon group in this specification means the saturated hydrocarbon group and unsaturated hydrocarbon group which were not comprised in the main chain but comprised only the chain structure. However, both linear hydrocarbon groups and branched hydrocarbon groups are included. The alicyclic hydrocarbon group means a hydrocarbon group containing only an alicyclic hydrocarbon structure as a ring structure and not containing an aromatic ring structure. However, it is not necessary to be comprised only by the structure of an alicyclic hydrocarbon, The thing which has a chain structure in the part is also included.

Specific examples of the monovalent chain hydrocarbon group in R ¹ include, for example, 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 nonyl group, a decyl group, and an undecyl group. , Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, octadecyl group, icosyl group, vinyl group, propenyl group, butenyl group, pentenyl group, ethynyl group, propynyl group and the like. Specific examples of the monovalent alicyclic hydrocarbon group include, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclopentylmethyl group, a cyclohexyl group, a cyclohexylmethyl group, a cyclohexenyl group, a cycloheptyl group, Cyclooctyl group, cyclononyl group, cyclodecyl group, cycloundecyl group, cyclododecyl group, cyclotridecyl group, cyclotetradecyl group, cyclopentadecyl group, cyclooctadecyl group, cycloicosyl group, bicyclohexyl group, decahydronaphthyl group , Norbornyl group, methylnorbornyl group, adamantyl group and the like.
The monovalent organic group in R ¹ preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and still more preferably 1 to 10 carbon atoms.

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

Specifically, as the divalent chain hydrocarbon group in R ² , R ³ and R ⁴ , for example, methylene group, ethylene group, propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene Group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, octadecylene group, icosylene group, vinylene group, propenylene group, butenylene group, pentenylene group, ethynylene group, propynylene group, etc .; Examples of the cyclic hydrocarbon group include cyclopropylene group, cyclobutylene group, cyclopentylene group, cyclohexylene group, cyclohexenylene group, cycloheptylene group, cyclooctylene group, cyclononylene group, cyclodecylene group, cycloundecylene group, and cyclododecylene. Group, And a cyclotridecylene group, a cyclotetradecylene group, a cyclopentadecylene group, a cyclooctadecylene group, a cycloicosylene group, a bicyclohexylene group, a norbornylene group, an adamantylene group, and the like.
The divalent organic group in 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, The number 1 to 5 is particularly preferable. In the formula (1), when a plurality of R ² are present, they may be the same as or different from each other. When a plurality of R ³ are present, they may be the same as or different from each other.

X ¹ in the above formula (1) is a nitrogen-containing aromatic heterocycle, and the nitrogen-containing aromatic heterocycle is bonded to a nitrogen atom (nitrogen atom to which R ¹ is bonded) 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 nitrogen atoms as heteroatoms, or may contain nitrogen atoms and heteroatoms other than nitrogen atoms (oxygen atoms, sulfur atoms, etc.). Specific examples of the nitrogen-containing aromatic heterocycle in X ¹ include, for example, a pyrrole ring, an imidazole ring, a pyrazole ring, a triazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, an indole ring, a benzimidazole ring, a purine ring, Quinoline ring, isoquinoline ring, naphthyridine ring, quinoxaline ring, phthalazine ring, triazine ring, azepine ring, diazepine ring, acridine ring, phenazine ring, phenanthroline ring, oxazole ring, thiazole ring, carbazole ring, thiadiazole ring, benzothiazole ring, phenothiazine Ring, oxadiazole ring and the like. X ¹ may be one in which a substituent is introduced into the carbon atom constituting the ring exemplified above. Examples of the substituent include a halogen atom and a monovalent organic group having 1 to 20 carbon atoms. Specific examples of the monovalent organic group include the groups exemplified as the monovalent organic group for R ¹ .

Among these, as X ¹ , the ring skeleton is a pyrrole ring, imidazole ring, pyrazole ring, triazole ring, pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, benzimidazole ring, naphthyridine ring, phthalazine ring, quinoxaline ring, triazine It is preferably a ring, an azepine 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, a pyridazine ring or a pyrazine ring.
Incidentally, bonding position to R ² in a nitrogen-containing aromatic heterocycle is not particularly limited. For example, when the nitrogen-containing aromatic heterocycle as X ¹ is a 5-membered ring, it can be the 1-position, 2-position or 3-position, and when it is a 6-membered ring, the 1-position, 2-position , 3-position or 4-position. When n is 2 or 3, the plurality of X ¹ independently have the above definition.

X ² in the above formula (1) is a cyclic ether group or a polymerizable unsaturated group. The cyclic ether group is preferably an epoxy group (oxiranyl group) or an oxetanyl group, and more preferably an epoxy group. Further, the polymerizable unsaturated group only needs to have a carbon-carbon double bond, and specifically, it may be an acryloxy group, a methacryloxy group, a vinyl group, a vinyloxy group, a maleimide group or a styryl group. preferable.

（式（１−１）中、Ｒ^５は、２価の鎖状炭化水素基又は脂環式炭化水素基であり、ｔは０又は１である。Ｒ^１及びＸ^１は、それぞれ上記式（１）と同義である。）

（式（１−２）中、Ｒ^６及びＲ^７は、それぞれ独立に２価の鎖状炭化水素基又は脂環式炭化水素基であり、ｒは１又は２である。Ｘ^１及びＸ^２は、それぞれ上記式（１）と同義である。）

（式（１−３）中、Ｒ^８は、−ＣＯ−に対して鎖状炭化水素基又は脂環式炭化水素基で結合する２価の有機基である。Ｒ^２及びＸ^１は、それぞれ上記式（１）と同義である。） Preferred 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), a compound represented by the following formula (1-3), and the like. Is mentioned.

(In Formula (1-1), R ⁵ is a divalent chain hydrocarbon group or alicyclic hydrocarbon group, and t is 0 or 1. R ¹ and X ¹ are each represented by the above formula ( It is synonymous with 1).

(In formula (1-2), R ⁶ and R ⁷ are each independently a divalent chain hydrocarbon group or alicyclic hydrocarbon group, and r is 1 or 2. X ¹ and X ² Are respectively synonymous with the above formula (1).)

(In Formula (1-3), R ⁸ is a divalent organic group bonded to —CO— with a chain hydrocarbon group or an alicyclic hydrocarbon group. R ² and X ¹ are each (It is synonymous with the above formula (1).)

The compound represented by the above formula (1-1), R ¹ represents a hydrogen atom, a monovalent chain-like hydrocarbon group or a monovalent alicyclic hydrocarbon having 3 to 10 carbon atoms having 1 to 10 carbon atoms It is preferably a group, more preferably a hydrogen atom or a monovalent chain hydrocarbon group having 1 to 5 carbon atoms, and 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, and a divalent chain having 1 to 10 carbon atoms. It is more preferably a hydrocarbon group, particularly preferably a divalent chain hydrocarbon group having 1 to 5 carbon atoms. Further, preferred examples of X ¹ can be applied to the description of preferred embodiments given in X ¹ of the formula (1).
t is 0 or 1, and is preferably 0 in that a liquid crystal alignment film with less deterioration under a severe use environment can be obtained.

On the other hand, the compound represented by the above formula (1-2), examples of ^{R 6} and ^{R 7,} a divalent alicyclic divalent chain hydrocarbon group or a C3-10 having 1 to 10 carbon atoms It is preferably a formula hydrocarbon group, more preferably a chain hydrocarbon group having 1 to 10 carbon atoms, and particularly preferably a chain hydrocarbon group having 1 to 5 carbon atoms. In the molecule, R ⁶ and R ⁷ may be the same as or different from each other. Preferred examples of X ^1, can be applied to the description of preferred embodiments given in X ¹ of the formula (1). 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 particularly preferably an epoxy group.
r is 1 or 2, and is preferably 2.

In addition, regarding the compound represented by the above formula (1-3), examples of the divalent organic group in R ⁸ include the groups exemplified as specific examples of R ² and R ³ in the above formula (1). . Preferably it is C1-C19, More preferably, it is C1-C9. 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, and a divalent chain having 1 to 10 carbon atoms. It is more preferably a hydrocarbon group, particularly preferably a divalent chain hydrocarbon group having 1 to 5 carbon atoms. Preferred examples of X ¹ can be applied to the description of preferred embodiments given in X ¹ of the formula (1). In addition, several X < ¹ > in Formula (1-3) may mutually be same or different.

  The compound (B) is a compound represented by the above formula (1-1), the above formula (1-2), in that a liquid crystal alignment film having as little deterioration as possible can be obtained even under a severe use environment. ) And at least one selected from the group consisting of compounds represented by the above formula (1-3). Among these, the compound represented by the above formula (1-1) is particularly preferable.

Specific examples of the compound (B) contained in the liquid crystal aligning agent of the present invention include compounds represented by the following formulas (ma-1) to (ma-39), for example. Of the following formulas, formulas (ma-1) to (ma-19) correspond to specific examples of the compound represented by formula (1-1), and formulas (ma-26) to (ma-39) ) Corresponds to a specific example of a compound represented by the above formula (1-2), and formulas (ma-20) to (ma-25) correspond to a compound represented by the above formula (1-3). As said compound (B), these can be used individually by 1 type or in combination of 2 or more types.

  The compounding ratio of the compound (B) is preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the total polymer contained in the liquid crystal aligning agent. By setting the compounding ratio of the compound (B) to 0.1 parts by weight or more, it is possible to suitably obtain an effect that a highly reliable liquid crystal alignment film capable of maintaining a voltage holding ratio even under a severe use environment can be obtained. By adjusting the amount to 30 parts by weight or less, the mechanical strength and electrical characteristics of the liquid crystal alignment film can be prevented from being impaired. More preferably, it is 0.5-25 weight part, More preferably, it is 1.0-20 weight part.

<Other ingredients>
The liquid crystal aligning agent of this invention may contain the other component as needed. Examples of such other components include other polymers other than the polymer (A) and compounds having at least one epoxy group in the molecule (however, the compounds corresponding to the compound (B) are excluded. And an epoxy group-containing compound) and a functional silane compound.

<Other polymers>
The above other polymers can be used for improving solution properties and electrical properties. Examples of such other polymers include polyorganosiloxane, polyester, polyamide, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, and poly (meth) acrylate.
When adding another polymer to a liquid crystal aligning agent, it is preferable that the mixture ratio is 50 weight part or less with respect to a total of 100 weight part of the polymer contained in a liquid crystal aligning agent. The amount is more preferably 40 parts by weight, and still more preferably 0.1 to 30 parts by weight.

<Epoxy group-containing compound>
The epoxy group-containing compound can be used to improve the adhesion and electrical properties with the substrate surface in the liquid crystal alignment film. Examples of such epoxy group-containing compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1 , 6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, N, N, N ′, N′-tetraglycidyl-m-xylylene diene Amine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4′-diamy Diphenylmethane, N, N-diglycidyl - benzylamine, N, N-diglycidyl - aminomethyl cyclohexane, N, N-diglycidyl - may be mentioned as being preferred and cyclohexylamine. In addition, as an example of the epoxy group-containing compound, an epoxy group-containing polyorganosiloxane described in International Publication No. 2009/096598 can be used.
When these epoxy compounds are added to the liquid crystal aligning agent, the blending ratio is preferably 40 parts by weight or less, and 0.1 to 30 parts by weight with respect to a total of 100 parts by weight of the polymer contained in the liquid crystal aligning agent. More preferred.

<Functional silane compound>
The functional silane compound can be used for the purpose of improving the printability of the liquid crystal aligning agent. Examples of such functional silane compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl). ) -3-Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3- Aminopropyltrimethoxysilane, N-triethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-trimethoxysilyl -3,6- Methyl azananoate, N-benzyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, glycidoxymethyltrimethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-glycid And xylpropyltrimethoxysilane.
When these functional silane compounds are added to the liquid crystal aligning agent, the blending ratio is preferably 2 parts by weight or less, based on the total of 100 parts by weight of the polymer contained in the liquid crystal aligning agent, 2 parts by weight is more preferred.
As other components, in addition to the above, a compound having at least one oxetanyl group in the molecule, an antioxidant, or the like can be used.

<Solvent>
The liquid crystal aligning agent of the present invention is preferably constituted by dissolving the polymer (A) and the compound (B), and other components optionally blended as necessary, in an organic solvent.
Here, examples of the solvent used for preparing the liquid crystal aligning agent of the present invention include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, 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 ethyl ether, ethylene glycol n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl 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 monomethyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether , Ethylene carbonate, propylene carbonate and the like. These can be used individually by 1 type or in mixture of 2 or more types.

  The solid content concentration in the liquid crystal aligning agent of the present invention (the ratio of the total weight of components other than the solvent of the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, and the like. The range is preferably 1 to 10% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface as described later, and preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that becomes a liquid crystal alignment film. 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 excessive and a good liquid crystal alignment film cannot be obtained, and the viscosity of the liquid crystal aligning agent increases and the coating characteristics are increased. Is inferior.

The particularly preferable range of the solid content concentration varies depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, in the case of the spinner method, the solid content concentration is particularly preferably in the range of 1.5 to 4.5% by weight. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the inkjet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s.
The temperature at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 10-100 degreeC, More preferably, it is 20-80 degreeC. In mixing the polymer (A) and the compound (B), the compound (B) may be added directly to the polymer solution in which the polymer (A) is dissolved. Is preferably dissolved in an appropriate solvent (for example, the polymer (A) is a soluble solvent), and then the solution and the polymer solution are mixed.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal alignment film of the present invention is formed by the liquid crystal aligning agent prepared as described above. Moreover, the liquid crystal display element of this invention comprises the liquid crystal aligning film formed using the liquid crystal aligning agent of this invention. The drive mode to which the liquid crystal display element of the present invention is applied is not particularly limited, and can be applied to various drive modes such as TN type, STN type, IPS type, FFS type, VA type, MVA type, and PSA type.

  The liquid crystal display element of the present invention can be produced, for example, by the following steps (1) to (3). In step (1), the substrate to be used varies depending on the desired drive mode. Steps (2) and (3) are common to each drive mode.

[Step (1): Formation of coating film]
First, the liquid crystal aligning agent of this invention is apply | coated on a board | substrate, Then, a coating film is formed on a board | substrate by heating an application surface.
(1-1) When manufacturing a TN type, STN type, VA type, MVA type or PSA type liquid crystal display element, a pair of substrates each provided with a patterned transparent conductive film is used as a pair. The liquid crystal aligning agent of the present invention is preferably applied onto the surface on which the transparent conductive film is formed, preferably by an offset printing method, a spin coating method, a roll coater method or an ink jet printing method. Here, as the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly (cycloaliphatic olefin) can be used. As a transparent conductive film provided on one surface of the substrate, an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), etc. Can be used. In order to obtain a patterned transparent conductive film, for example, a method of forming a pattern by photo-etching 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, etc. be able to. In applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate surface and the transparent conductive film and the coating film, a functional silane compound or a functional titanium compound is formed on the surface of the substrate surface on which the coating film is formed. It is also possible to perform a pretreatment to apply the above in advance.

  After the application of the liquid crystal aligning agent, preheating (pre-baking) is preferably performed for the purpose of preventing dripping of the applied aligning agent. The pre-baking temperature is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 40 to 100 ° C. The pre-bake time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Thereafter, a firing (post-baking) step is carried out for the purpose of completely removing the solvent and, if necessary, for thermal imidization of the amic acid structure present in the polymer. The firing temperature (post-bake temperature) at this time is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The post-bake time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. Thus, the film thickness of the formed film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.

  (1-2) When manufacturing an IPS type or FFS type liquid crystal display element, an electrode forming surface of a substrate provided with an electrode made of a transparent conductive film or a metal film patterned in a comb shape, and an electrode are provided. The liquid crystal aligning agent of this invention is each apply | coated to one surface of the counter substrate which is not, and then a coating film is formed by heating each application surface. Regarding the material used for the substrate and the transparent conductive film, the coating method, the heating conditions after coating, the patterning method for the transparent conductive film or the metal film, the pretreatment of the substrate, and the preferred film thickness of the coating film to be formed The same as (1-1). As the metal film, for example, a film made of a metal such as chromium can be used.

  In both cases (1-1) and (1-2), after applying a liquid crystal aligning agent on the substrate, a coating film to be an alignment film is formed by removing the organic solvent. At this time, when the polymer contained in the liquid crystal aligning agent of the present invention is a polyamic acid, a polyamic acid ester, or an imidized polymer having an imide ring structure and an amic acid structure, It is good also as a more imidized coating film by advancing the dehydration ring-closing reaction by further heating after the coating film formation.

[Step (2): rubbing treatment]
When manufacturing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal display element, the coating film formed in the above step (1) is fixed by a roll wound with a cloth made of fibers such as nylon, rayon, and cotton. A rubbing process that rubs in the direction is performed. Thereby, the orientation ability of liquid crystal molecules is imparted to the coating film to form a liquid crystal orientation film. On the other hand, when manufacturing a VA type liquid crystal display element, the coating film formed in the step (1) can be used as it is as a liquid crystal alignment film, but the coating film may be subjected to a rubbing treatment. In addition, for the liquid crystal alignment film after the rubbing treatment, a process for changing the pretilt angle of a part of the liquid crystal alignment film by irradiating a part of the liquid crystal alignment film with ultraviolet rays, After forming a resist film in part and performing a rubbing process in a direction different from the previous rubbing process, a process for removing the resist film is performed so that the liquid crystal alignment film has different liquid crystal alignment capabilities for each region. Good. In this case, it is possible to improve the visibility characteristics of the obtained liquid crystal display element.
When manufacturing a PSA type liquid crystal display element, the following step (3) may be carried out using the coating film formed in the above step (1) as it is, but the fall of the liquid crystal molecules is controlled and the alignment is divided. A weak rubbing treatment may be performed for the purpose of performing the above in a simple manner.

[Step (3): Construction of liquid crystal cell]
(3-1) A liquid crystal cell is manufactured by preparing two substrates on which a liquid crystal alignment film is formed as described above and disposing a liquid crystal between the two substrates facing each other. In order to manufacture a liquid crystal cell, the following two methods are mentioned, for example. First, the first method is a conventionally known method. In this method, first, two substrates are arranged to face each other through a gap (cell gap) so that the respective liquid crystal alignment films face each other, and the peripheral portions of the two substrates are bonded together using a sealant, and the substrate surface And after injecting and filling a liquid crystal in the cell gap divided by the sealing agent, a liquid crystal cell is manufactured by sealing the injection hole. The second method is a method called an ODF (One Drop Fill) method. In this method, for example, an ultraviolet light curable sealing material is applied to a predetermined place on one of the two substrates on which the liquid crystal alignment film is formed, and a predetermined number of places on the liquid crystal alignment film surface are applied. After the liquid crystal is dropped on the other substrate, the other substrate is bonded so that the liquid crystal alignment film faces. A liquid crystal cell is manufactured by spreading the liquid crystal over the entire surface of the substrate and then irradiating the entire surface of the substrate with ultraviolet light to cure the sealant. Regardless of which method is used, the liquid crystal cell manufactured as described above is further heated to a temperature at which the liquid crystal used takes an isotropic phase, and then slowly cooled to room temperature, thereby removing the flow alignment at the time of filling the liquid crystal. It is desirable to do.

  As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used. Examples of the liquid crystal include nematic liquid crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferable. For example, Schiff base liquid crystals, azoxy liquid crystals, biphenyl liquid crystals, phenyl cyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals. Biphenylcyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane liquid crystal, cubane liquid crystal, and the like can be used. Further, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, and cholesteryl carbonate; chiral agents such as those sold under the trade names “C-15” and “CB-15” (manufactured by Merck & Co., Inc.). A ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate may be added and used.

(3-2) When manufacturing a PSA type liquid crystal display element, 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 a liquid crystal. Thereafter, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates. The voltage applied here can be, for example, 5 to 50 V direct current or alternating current. Moreover, as light to irradiate, the ultraviolet-ray and visible light which contain light with a wavelength of 150-800 nm can be used, for example, However, The ultraviolet-ray containing light with a wavelength of 300-400 nm is preferable. As a light source of irradiation light, for example, a low pressure mercury lamp, a high pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used. In addition, the ultraviolet rays in the above preferable wavelength region can be obtained by means of using a light source in combination with, for example, a filter diffraction grating. The irradiation dose of light, preferably less than 1,000 J / ^{m 2} or more 200,000 J / ^{m 2,} more preferably from 1,000~100,000J / ^{m 2.}

  And the liquid crystal display element of this invention can be obtained by bonding a polarizing plate on the outer surface of a liquid crystal cell. As a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film itself in which a polarizing film called an “H film” in which iodine is absorbed while stretching and aligning polyvinyl alcohol is sandwiched between cellulose acetate protective films The polarizing plate which consists of can be mentioned. When the rubbing treatment is performed on the coating film, the two substrates are arranged to face each other so that the rubbing directions in each coating film are at a predetermined angle, for example, orthogonal or antiparallel.

  The liquid crystal display element of the present invention can be effectively applied to various devices, such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, It can be used for display devices such as various monitors and liquid crystal televisions.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

In the following Examples and Comparative Examples, the imidization ratio of polyimide 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.
[Imidation rate of polyimide]
The polyimide solution was poured into pure water, and the resulting precipitate was sufficiently dried under reduced pressure at room temperature, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance. From the obtained ¹ H-NMR spectrum, the imidation ratio [%] was determined by the following formula (x).
Imidation rate [%] = (1-A ¹ / A ² × α) × 100 (x)
(In Formula (x), A ¹ is the peak area derived from proton of NH group appearing in the vicinity of the chemical shift 10 ppm, A ² is the peak area derived from other protons, alpha precursor (polyamic acid polymer The number ratio of other protons to one proton of NH group in)
[Solution viscosity of polymer solution]
The solution viscosity [mPa · s] of the polymer solution was measured at 25 ° C. using an E-type rotational viscometer for a solution prepared to a polymer concentration of 10% by weight using a predetermined solvent.
[Weight average molecular weight of polymer]
The weight average molecular weight is a polystyrene equivalent value measured by gel permeation chromatography under the following conditions.
Column: Tosoh Co., Ltd., TSKgelGRCXLII
Solvent: Tetrahydrofuran Temperature: 40 ° C
Pressure: 68 kgf / cm ²
[Epoxy equivalent]
The epoxy equivalent was measured by the hydrochloric acid-methyl ethyl ketone method described in JIS C 2105.

<Synthesis of polymer (A)>
[Synthesis Example 1: Synthesis of polyimide (PI-1)]
2,2.4 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 diamine ) And 10.5 g (0.02 mol) of cholestanyl 3, HC-diaminobenzoate (HCDA) are dissolved in 166 g of N-methyl-2-pyrrolidone (NMP) and reacted at 60 ° C. for 6 hours to obtain a polyamic acid. A solution containing 20% by weight was obtained. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 90 mPa · s.
Next, NMP was added to the obtained polyamic acid solution to obtain a polyamic acid concentration of 7% by weight, 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. . After the dehydration cyclization reaction, the solvent in the system was replaced with new NMP (by this operation, pyridine and acetic anhydride used in the dehydration cyclization reaction were removed from the system. The same applies hereinafter), whereby the imidation rate was about 68. A solution containing 26% by weight of polyimide (PI-1) was obtained. A small amount of the obtained polyimide solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 45 mPa · s.

[Synthesis Example 2: Synthesis of polyimide (PI-2)]
22.5 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 10.7 g (0.07 mol) of 3,5-diaminobenzoic acid (35DAB) as diamine, cholestanyloxy-2,4-diaminobenzene ( HCODA) 7.35 g (0.015 mol) and 6.94 g (0.015 mol) of the compound (LDA) represented by the above formula (D-1-5) were dissolved in 190 g of NMP, and 6 hours at 60 ° C. The reaction was performed to obtain a solution containing 20% by weight of polyamic acid. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 80 mPa · s.
Next, NMP was added to the obtained polyamic acid solution to obtain a polyamic acid concentration of 7% by weight, 15.7 g of pyridine and 20.3 g of acetic anhydride were added, and a dehydration ring closure reaction was performed at 110 ° C. for 4 hours. . After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 26% by weight of polyimide (PI-2) having an imidation ratio of about 80%. A small amount of the obtained polyimide solution was taken, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 40 mPa · s.

[Synthesis Example 3: Synthesis of polyimide (PI-3)]
1,8.7 g (0.075 mol) of 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride (BODA) as tetracarboxylic dianhydride And 1.90 g (0.025 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CB), 10.7 g (0.07 mol) of 35DAB as a diamine and 1,3-diamino-4- { 4- [trans-4- (trans-4-n-pentylcyclohexyl) cyclohexyl] phenoxy} benzene (PBCH5DAB, compound represented by the above formula (D-1-2)) 13.1 g (0.03 mol) , Dissolved in 190 g of NMP and reacted at 60 ° C. for 6 hours to obtain a solution containing 20% by weight of polyamic acid. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 85 mPa · s.
Next, NMP was added to the obtained polyamic acid solution to obtain a polyamic acid concentration of 7% by weight, 9.5 g of pyridine and 12.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. . After the dehydration and cyclization reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 26% by weight of polyimide (PI-3) having an imidation ratio of about 65%. A small amount of the obtained polyimide solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 45 mPa · s.

[Synthesis Example 4: Synthesis of polyimide (PI-4)]
As tetracarboxylic dianhydride, 110 g (0.50 mol) of TCA and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) naphtho 160 g (0.50 mol) of [1,2-c] furan-1,3-dione, 91 g (0.85 mol) of p-phenylenediamine (PDA) as a diamine, 1,3-bis (3-aminopropyl) ) 25 g (0.10 mol) of tetramethyldisiloxane and 25 g (0.040 mol) of 3,6-bis (4-aminobenzoyloxy) cholestane, and 1.4 g (0.015 mol) of aniline as a monoamine, 960 g of NMP And a reaction was conducted at 60 ° C. for 6 hours to obtain a solution containing polyamic acid. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 60 mPa · s.
Next, 2,700 g of NMP was added to the obtained polyamic acid solution, 390 g of pyridine and 410 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with new γ-butyrolactone to obtain about 2,500 g of a solution containing 15% by weight of polyimide (PI-4) having an imidation ratio of about 95%. A small amount of this solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 70 mPa · s.

[Synthesis Example 5: Synthesis of polyimide (PI-5)]
TCA 22.4 g (0.1 mol) as tetracarboxylic dianhydride, 8.6 g (0.08 mol) PDA as diamine, 2.0 g (0.01 mol) 4,4′-diaminodiphenylmethane and 4,4 ′ -3.2 g (0.01 mol) of diamino-2,2′-bis (trifluoromethyl) biphenyl was dissolved in 324 g of NMP, reacted at 60 ° C. for 4 hours, and a solution containing 10% by weight of polyamic acid was obtained. Obtained.
Next, 360 g of NMP was added to the obtained polyamic acid solution, 39.5 g of pyridine and 30.6 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 10% by weight of polyimide (PI-5) having an imidization ratio of about 93%. A small amount of the obtained polyimide solution was taken and measured, and the solution viscosity was 30 mPa · s.

[Synthesis Example 6: Synthesis of polyimide (PI-6)]
A polyamic acid solution was obtained in the same manner as in Synthesis Example 1 except that the diamine used was changed to 12.2 g (0.08 mol) of 35 DAB and 9.8 g (0.02 mol) of HCODA. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 80 mPa · s.
Next, imidization was performed by the same method as in Synthesis Example 1 to obtain a solution containing 26% by weight of polyimide (PI-6) having an imidization ratio of about 65%. A small amount of the obtained polyimide solution was taken, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 40 mPa · s.

[Synthesis Example 7: Synthesis of polyamic acid (PA-1)]
CB 200 g (1.0 mol) as tetracarboxylic dianhydride, 2,2′-dimethyl-4,4′-diaminobiphenyl 210 g (1.0 mol) as diamine, NMP 370 g and γ-butyrolactone 3,300 g mixed It melt | dissolved in the solvent and reacted at 40 degreeC for 3 hours, and obtained the solution containing 10 weight% of polyamic acids (PA-1). The solution viscosity measured by separating a small amount of the obtained polyamic acid solution was 160 mPa · s.

[Synthesis Example 8: Synthesis of polyamic acid (PA-2)]
The tetracarboxylic dianhydride used is pyromellitic dianhydride (PMDA) 196 g (0.9 mol) and CB 19.6 g (0.1 mol), and the diamine is PDA 0.2 mol and 4,4 ′. A solution containing 10% by weight of polyamic acid (PA-2) was obtained in the same manner as in Synthesis Example 7 except that -diaminodiphenyl ether (DDE) was used. A solution viscosity of 170 mPa · s obtained by measuring a small amount of the resulting polyamic acid solution was 170 mPa · s.

[Synthesis Example 9: Synthesis of polyorganosiloxane (APS-1)]
In a reaction vessel equipped with a stirrer, thermometer, dropping funnel and reflux condenser, 100.0 g of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (ECETS), 500 g of methyl isobutyl ketone and 10.0 g of triethylamine were added. Charged and mixed at room temperature. Next, 100 g of deionized water was dropped from the dropping funnel over 30 minutes, and the reaction was performed at 80 ° C. for 6 hours while stirring under reflux. After completion of the reaction, the organic layer is taken out, washed with 0.2 wt% ammonium nitrate aqueous solution until the water after washing becomes neutral, and then the solvent and water are distilled off under reduced pressure, thereby reactive polyorganosiloxane. (EPS-1) was obtained as a viscous transparent liquid. When this reactive polyorganosiloxane was subjected to ¹ H-NMR analysis, a peak based on an epoxy group was obtained in the vicinity of chemical shift (δ) = 3.2 ppm according to the theoretical intensity. Was confirmed not to happen. The obtained reactive polyorganosiloxane had a weight average molecular weight Mw of 3,500 and an epoxy equivalent of 180 g / mol.
Next, in a 200 mL three-necked flask, 10.0 g of reactive polyorganosiloxane (EPS-1), 30.28 g of methyl isobutyl ketone as a solvent, 3.98 g of 4-dodecyloxybenzoic acid as a reactive compound, and UCAT as a catalyst 0.10 g of 18X (trade name, manufactured by San Apro Co., Ltd.) was charged, and the reaction was performed at 100 ° C. with stirring for 48 hours. After completion of the reaction, a solution obtained by adding ethyl acetate to the reaction mixture was washed with water three times, the organic layer was dried using magnesium sulfate, and then the solvent was distilled off to obtain a liquid crystal alignment polyorganosiloxane (APS-). 9.0 g of 1) was obtained. The weight average molecular weight Mw of the obtained polymer was 9,900.

<Example 1>
[Preparation of liquid crystal aligning agent]
To a solution containing polyimide (PI-1) as the polymer (A), 5 parts by weight of an NMP solution of bis (3-pyridylmethyl) amine as the compound (B) is added to 100 parts by weight of the total polymer. A solution having a solvent composition of NMP: BC = 50: 50 (weight ratio) and a solid content concentration of 6.0% by weight was obtained. A liquid crystal aligning agent (S1) was prepared by filtering this solution using a filter having a pore diameter of 1 μm.
[Manufacture of liquid crystal cells]
The liquid crystal aligning agent (S1) prepared above was applied to a transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a liquid crystal aligning film printer (Nissha Printing Co., Ltd.), and hot at 80 ° C. After removing the solvent by heating (pre-baking) for 1 minute on the plate, heating (post-baking) for 30 minutes on a 210 ° C. hot plate was performed to form a coating film having an average film thickness of 80 nm.
The coating film is rubbed with a rubbing machine having a roll wrapped with a rayon cloth at a roll rotation speed of 500 rpm, a stage moving speed of 3 cm / sec, and a hair foot indentation length of 0.4 mm to give liquid crystal alignment ability. did. Then, ultrasonic cleaning was performed in ultrapure water for 1 minute, and then drying was performed in a 100 ° C. clean oven for 10 minutes to obtain a substrate having a liquid crystal alignment film. This operation was repeated to obtain a pair (two) of substrates having a liquid crystal alignment film.
Next, on each of the pair of substrates, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is applied to the outer edge of the surface having the liquid crystal alignment film, and then the layers are stacked so that the liquid crystal alignment film surfaces face each other. And then the adhesive was cured. Next, a nematic liquid crystal (MLC-6221 manufactured by Merck & Co., Inc.) 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 photo-curing adhesive to produce a liquid crystal cell.

[Evaluation of reliability of liquid crystal alignment film]
A voltage of 5 V was applied to the liquid crystal cell obtained above with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio (VHR1) 167 milliseconds after release of application was measured. Next, the liquid crystal cell was allowed to stand in an 80 ° C. oven under LED lamp irradiation 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 with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio (VHR2) 167 milliseconds after the application release was measured. The measuring device used was “VHR-1” manufactured by Toyo Corporation. The change rate (ΔVHR) of VHR at this time was calculated by the following mathematical formula (y), and the reliability of the liquid crystal alignment film was evaluated by ΔVHR. Evaluation is when the ΔVHR is 1% or less, the reliability is “very good (◎)”, and when the ΔVHR is greater than 1% and 2% or less, the reliability is “good (◯)”, more than 2% When it was large, the reliability was evaluated as “bad” (x). The results are shown in Table 1 below.
ΔVHR [%] = (VHR1−VHR2) / (VHR1) × 100 (y)

In Table 1, the “addition amount” of the compound (B) indicates a blending ratio [parts by weight] with respect to a total of 100 parts by weight of the polymer components in the liquid crystal aligning agent. The abbreviations of the compound (B) in Table 1 have the following meanings, respectively.
Bis-AMP: Bis (3-pyridylmethyl) amine (compound represented by the above formula (ma-1))
Tri-AMP: Tri (3-pyridylmethyl) amine (compound represented by the above formula (ma-14))
Epo-AMP: Compound represented by the above formula (ma-26) Epo-AMPm: Compound represented by the above formula (ma-27) DA-AMP: Compound represented by the above formula (ma-20) DA- AEIm: Compound represented by the above formula (ma-21) NM-AMP: 3- (methylaminomethyl) pyridine 3-AMP: 3-aminomethylpyridine

<Examples 2 to 13, Comparative Examples 1 and 2>
Liquid crystal aligning agents (S2) to (S13) and (R1) in the same manner as in Example 1 except that the type of polymer (A) used and the type and amount of compound (B) were changed as shown in Table 1 above. , (R2) were prepared respectively. Each of the prepared liquid crystal aligning agents was evaluated for the reliability of the liquid crystal aligning film in the same manner as in Example 1. The results are shown in Table 1 above. In addition, in Table 1, about Examples 7-9 which used two types of polymers as a polymer (A), the usage-ratio (weight%) of each polymer with respect to the whole quantity of the used polymer is shown collectively. It was.

  As shown in Table 1, in Examples 1 to 13 using the liquid crystal aligning agent containing the compound (B), after being exposed to light irradiation and a stress environment of 80 ° C. for a long time (200 hours), However, the voltage holding ratio did not decrease much and the reliability was good. Among them, in particular, in Examples 1 to 9 using Bis-AMP or Tri-AMP as the compound (B), ΔVHR is 0.6% or less, and the decrease in voltage holding ratio due to application of light stress and thermal stress is slight. there were. On the other hand, in Comparative Examples 1 and 2 not containing the compound (B), the voltage holding ratio was greatly reduced by the application of light stress and thermal stress.

Claims (5)

A liquid crystal aligning agent containing at least one polymer (A) selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, and a compound (B) represented by the following formula (1).

(In the formula (1), R ¹ is a hydrogen atom, or a monovalent organic group bonded to a nitrogen atom to which R ² and R ³ are bonded by a chain hydrocarbon group or an alicyclic hydrocarbon group. R ² and R ³ are each independently a chain hydrocarbon group, alicyclic hydrocarbon group or * —CO—R ⁴ — (where R ^{4 represents} a nitrogen atom to which R ¹ is bonded. Is a divalent chain hydrocarbon group or alicyclic hydrocarbon group, and * is a divalent organic group bonded by a bond to the 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, and n is an integer of 1 to 3, provided that n = 3 when a m = 0 if .n is 2 or 3, a plurality of ^{R 2} and ^{X 1} may be the same or different, (3-n-m) = 2 field , A plurality of ^{R 3} and ^{X 2} may be the same or different.)   The liquid crystal aligning agent of Claim 1 whose content rate of the said compound (B) is 0.1-30 weight part with respect to a total of 100 weight part of the polymer contained in a liquid crystal aligning agent.   The polymer (A) is 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8- A polymer obtained by reacting a diamine with a tetracarboxylic dianhydride containing at least one selected from the group consisting of dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride, Item 3. The liquid crystal aligning agent according to item 1 or 2.   The liquid crystal aligning film formed using the liquid crystal aligning agent as described in any one of Claims 1 thru | or 3.   A liquid crystal display device comprising the liquid crystal alignment film according to claim 4.