TW201930401A - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

A liquid crystal alignment agent containing a polyimide that is a reaction product of a diamine component and a tetracarboxylic acid dianhydride derivative component comprising at least one species selected from an aliphatic tetracarboxylic acid dianhydride and an alicyclic tetracarboxylic acid dianhydride, wherein the diamine component contains at least one species selected from diamines represented by formula [A], and the imidization rate of the polyimide is 70% or greater. In the formula: P1 and P2 are phenyl or biphenyl groups, and a hydrogen atom on an aromatic ring thereof may be substituted with a methyl group or a fluorine group; Q is a divalent organic group, and n1 and n2 are integers of 0 to 5, Q being an oxygen atom when n1 and/or n2 is 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.

The liquid crystal display element is constituted by sandwiching a liquid crystal layer with a transparent pair of electrodes provided with electrodes. In the liquid crystal display device, an organic film made of an organic material such that a liquid crystal is in a desired alignment state between the substrates is used as a liquid crystal alignment film. In other words, the liquid crystal alignment film is a constituent member of the liquid crystal display element, and is formed on a surface of the substrate sandwiching the liquid crystal that is in contact with the liquid crystal, and functions to align the liquid crystal in a certain direction between the substrates. Further, the pretilt angle of the liquid crystal can be controlled by the liquid crystal alignment film. A method in which the pretilt angle is low mainly by selecting a structure of polyimine (see Patent Documents 1 and 2) is known.
[Previous Technical Literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. Hei 9-188761
[Patent Document 2] Japanese Patent Laid-Open No. Hei 10-123532

[Problems to be solved by the invention]

On the other hand, with the recent increase in the performance of liquid crystal display elements, it is known that liquid crystal display elements are used for vehicles, such as car navigation systems, instrument panels, and monitoring, in addition to applications such as large-screen and high-definition liquid crystal televisions. In the case of a camera or a medical camera screen, in terms of the viewing angle characteristics, the friction alignment film also requires a lower pretilt angle than before.
Further, the viewing angle dependence of the color tone derived from the pretilt angle is referred to as a problem as a problem, and in order to solve the problem, an alignment film having a pretilt angle of 1 degree or less is specifically required.

In order to achieve the above object, the inventors of the present invention have found that the liquid crystal alignment agent having the following constitution is the best in achieving the above object, and the present invention has been completed.

[Means to solve the problem]

As such, the present invention has the following gist based on the above-mentioned findings.
A liquid crystal alignment agent containing a reactant of a carboxylic acid dianhydride derivative component and a diamine component, which are selected from at least one selected from the group consisting of a free aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride. A liquid crystal alignment agent of a polyimine, wherein the diamine component contains at least one selected from the group consisting of a diamine of the following formula [A] (hereinafter also referred to as a specific diamine), and a polyamidomine. The amination rate is 70% or more;

Wherein P ₁ and P ₂ are a phenyl group or a biphenyl group, and the hydrogen on the aromatic ring may be substituted with a methyl group or a fluorine group. Further, Q is a divalent organic group, and n1 and n2 are integers of 0 to 5. However, when at least one of n1 and n2 is 0, Q is an oxygen atom.
Preferable specific examples of [A] include diamines of the following formulas [A-1] to [A-6].

[Effects of the Invention]

By using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film which satisfies various characteristics required for a liquid crystal alignment film and imparts a low pretilt angle of 1 degree or less can be obtained.

<aliphatic, alicyclic tetracarboxylic acid derivatives>
The polyimine contained in the liquid crystal alignment agent of the present invention is a tetracarboxylic dianhydride composed of at least one selected from the group consisting of a free aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride. The polyimine precursor obtained by the derivative component and the diamine component containing a specific diamine is obtained by imidization (hereinafter, also referred to as a specific polymer). Specific examples and manufacturing methods of the materials used will be described in detail below.
The tetracarboxylic acid derivative used in the production of the polyimine precursor is not only a tetracarboxylic dianhydride but also a tetracarboxylic acid, a tetracarboxylic acid dihalide compound, a dicarboxylic acid dialkyl ester, or a tetracarboxylic acid derivative thereof. Dialkyl carboxylate dihalide.
The aliphatic or alicyclic tetracarboxylic dianhydride or a derivative thereof is preferably those represented by the following formula (4).

In the formula (4), preferred structures of X ₁ include the following formulae (X1-1) to (X1-24).

In the formulae (X1-1) to (X1-4), R ₃ to R ₂₃ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, and carbon. The alkynyl group having 2 to 6 or the monovalent organic group having 1 to 6 carbon atoms of a fluorine atom, or a phenyl group. From the viewpoint of liquid crystal alignment, R ₃ to R _{23 are} preferably a hydrogen atom, a halogen atom, a methyl group or an ethyl group; more preferably a hydrogen atom or a methyl group.
Specific examples of the formula (X1-1) include the following formulae (X1-1-1) to (X1-1-6). From the viewpoint of the liquid crystal alignment property and the sensitivity of the photoreaction, it is particularly preferably (X1-1-1).

<specific diamine>
The diamine component used for the production of the polyimine contained in the liquid crystal alignment agent of the present invention contains at least one selected from the diamines of the following formula [A].

Wherein P ₁ and P ₂ are a phenyl group or a biphenyl group, and the hydrogen on the aromatic ring may be substituted with a methyl group or a fluorine group. Further, Q is a divalent organic group, and n1 and n2 are integers of 0 to 5. However, when at least one of n1 and n2 is 0, Q is an oxygen atom.

Here, when (n1+n2)≧1, n1, and n2 are 0, Q is preferably an oxygen atom, and the formula [A] is represented by the following [A ́].

Wherein X is a divalent organic group selected from the following structures.

* indicates a bond to an oxygen atom, respectively.
Preferable specific examples of [A] include diamines of the following formulas [A-1] to [A-6]. These may be separate or plural combinations.

The preferred content of the diamine of the above formula [A] is preferably 40% to 80%, more preferably 40% to 70%, still more preferably 40% to 60% of the total diamine component.

<Other diamines>
In addition to the diamine of the above formula [A], the diamine component used in the production of the polyimine contained in the liquid crystal alignment agent of the present invention may be various diamines depending on the characteristics of the desired liquid crystal alignment agent. .
The other diamine is represented by the following formula (5).

In the above formula (5), each of A ₁ and A ₂ is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms.
The structure of Y ₁ is not particularly limited. Preferred structures include the following (Y-1) to (Y-177).

In the above formula, Me represents a methyl group, and R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.

From the viewpoint of improving the solubility of the polymer, it is preferred that the Y ₁ structure includes a structure represented by the following formula (6).

In the above formula (6), D is preferably detached at 150 to 230 ° C, more preferably at 180 to 230 ° C, and is substituted with a thermally detachable group of a hydrogen atom. Specific examples of Y including the structure represented by the above formula (6) include (Y-124) and (Y-158) to (Y-163).

<polylysine>
The polyaminic acid precursor of the polyimine precursor used in the present invention is derived from a tetracarboxylic dianhydride composed of at least one selected from the group consisting of a free aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride. The polyimine precursor obtained by the component and the diamine component containing a specific diamine can be produced by the method shown below.
Specifically, a tetracarboxylic dianhydride derivative component composed of at least one selected from the group consisting of a free aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride, and a diamine containing a specific diamine can be used. The component is synthesized in the presence of an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, for 30 minutes to 24 hours, preferably 1 to 12 hours.

The organic solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone in terms of solubility of the monomer and the polymer. These may be used alone or in combination of two or more. The concentration of the polymer is less likely to cause precipitation of the polymer and is easy to obtain a high molecular weight body, and is preferably from 1 to 30% by mass, more preferably from 5 to 20% by mass.

The polyamic acid obtained as described above is injected into a poor solvent while sufficiently stirring the reaction solution, whereby the polymer can be precipitated and recovered. Further, it can be precipitated several times, washed with a poor solvent, and then dried at room temperature or by heating to obtain a purified polyamine powder. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl quercetin, acetone, and toluene.

<Polyurethane>
The polyglycolate of one of the polyimine precursors used in the present invention can be produced by the method of (I), (II) or (III) shown below.

(I) In the case of polylysine, a polyphthalate can be synthesized by esterifying a polyamine obtained from a tetracarboxylic dianhydride and a diamine. Specifically, the polyglycine and the esterifying agent can be reacted in the presence of an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, for 30 minutes to 24 hours, preferably 1 to 4 hours to synthesize.

The esterifying agent is preferably one which can be easily removed by purification, and examples thereof include N,N-dimethylformamide dimethyl acetal and N,N-dimethylformamide diethyl acetal. N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamide dineopentyl butyl acetal, N,N-dimethylformamide di-t-butyl Acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene, 4 -(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride or the like. The amount of the esterifying agent used is preferably 2 to 6 moles per equivalent of the repeating unit of poly-proline.

The solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone or γ-butyrolactone in terms of solubility of the polymer. One type or a mixture of two or more types is used. The concentration of the polymer in the reaction liquid is less likely to cause precipitation of the polymer and is easy to obtain a high molecular weight body, and is preferably from 1 to 30% by mass, more preferably from 5 to 20% by mass.

(II) A case produced by a reaction of a tetracarboxylic acid diester dichloride with a diamine, which can be produced from a tetracarboxylic acid diester dichloride and a diamine. Specifically, the reaction can be carried out for 30 minutes in the presence of a base and an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, by using a tetracarboxylic acid diester dichloride and a diamine. It is synthesized in 24 hours, preferably 1 to 4 hours.

As the base, pyridine, triethylamine, 4-dimethylaminopyridine or the like can be used, and since the reaction proceeds gently, pyridine is preferred. The amount of the base to be used is easily removed, and the viewpoint of easily obtaining a high molecular weight body is preferably 2 to 4 times moles relative to the tetracarboxylic acid diester dichloride.

The solvent used for the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in terms of the solubility of the monomer and the polymer, and these may be used alone or in combination of two or more. . The concentration of the polymer in the reaction liquid is less likely to cause precipitation of the polymer and is easy to obtain a high molecular weight body, and is preferably from 1 to 30% by mass, more preferably from 5 to 20% by mass. Further, in order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for the synthesis of the polyglycolate is preferably only dehydrated, and is preferably in a nitrogen atmosphere to prevent incorporation of outside air.

(III) A case where a polyglycolate is produced by a reaction of a tetracarboxylic acid diester with a diamine, which can be produced by polycondensing a tetracarboxylic acid diester with a diamine. Specifically, the reaction can be carried out for 30 minutes to 24 minutes by using a tetracarboxylic acid diester and a diamine in the presence of a condensing agent, a base, and an organic solvent at 0 ° C to 150 ° C, preferably 0 ° C to 100 ° C. It is manufactured in an hour, preferably 3 to 15 hours.

As the condensing agent, triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N, N'- can be used. Carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholinium, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyl Urea 鎓 tetrafluoroborate, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2- Diphenyl ester of thio-3-benzoxazolyl)phosphonate. The amount of the condensing agent to be added is preferably 2 to 3 moles per mole of the tetracarboxylic acid diester.

As the base, a tertiary amine such as pyridine or triethylamine can be used. The amount of the base to be used is preferably from 2 to 4 times the molar amount of the diamine component, from the viewpoint of easy removal of the amount and easy availability of a high molecular weight body.

Further, in the above reaction, the reaction system is efficiently carried out by adding Lewis acid as an additive. The Lewis acid is preferably a lithium halide such as lithium chloride or lithium bromide. The amount of Lewis acid added is preferably from 0 to 1.0 times the molar amount of the diamine component.

In the method for producing the above three polyglycolates, a high molecular weight polyglycolate can be obtained, and in particular, the production method of the above (I) or (II) is particularly preferable.

The solution of the polyphthalate obtained as described above is poured into a poor solvent while being sufficiently stirred to precipitate a polymer. After several times of precipitation, after washing with a poor solvent, it can be dried at room temperature or by heating to obtain a purified polyphthalate powder. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl quercetin, acetone, and toluene.

<polyimine]
The polyimine used in the present invention can be produced by imidating the above polyamic acid or polyamidinate. The ruthenium imidization ratio of the polyimine used in the present invention is preferably from 70 to 99% from the viewpoint of electrical properties. When the polyimide is produced from a polyphthalate, a basic catalyst is added to the polyphthalate solution or a polyphthalic acid solution obtained by dissolving the polyphthalate resin powder in an organic solvent. The chemical imidization system is simple. The chemical hydrazine imidization is preferred because the ruthenium imidization reaction proceeds at a lower temperature and the molecular weight of the polymer is less likely to occur during the imidization of the hydrazine.

The chemical hydrazine imidation can be carried out by stirring the polyaminic acid or polyphthalate to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, the solvent used in the above polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferred because it has a moderate alkalinity for the reaction. Further, examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Among them, in particular, when acetic anhydride is used, it is preferred because the purification after the completion of the reaction becomes easy.

The temperature at which the hydrazine imidization reaction is carried out is, for example, -20 ° C to 120 ° C, preferably 0 ° C to 100 ° C, and the reaction time can be carried out at 1 to 100 hours. The amount of the alkaline catalyst is 0.5 to 30 moles, preferably 2 to 20 moles, of the prolyl group, and the amount of the anhydride is 1 to 50 moles, preferably 3 to the amidate group. 30 moles. The ruthenium imidation ratio of the obtained polymer can be controlled by adjusting the amount of the catalyst, the temperature, and the reaction time.

In the solution after the imidization reaction of the polyperurethane or polylysine, the added catalyst or the like remains, and therefore, the obtained ruthenium iodide is preferably polymerized by the means described below. The material is recovered and redissolved in an organic solvent to serve as a liquid crystal alignment agent of the present invention.

The solution of the polyimine obtained as described above is poured into a poor solvent while being sufficiently stirred to precipitate a polymer. After several times of precipitation, after washing with a poor solvent, it can be dried at room temperature or by heating to obtain a purified polyphthalate powder.

The poor solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cyanidin, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene.

<Liquid alignment agent>
The liquid crystal alignment agent of the present invention has a form of a solution containing a polymer of a specific polymer dissolved in an organic solvent. The molecular weight of the polyimine precursor and the polyimine of the present invention is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, still more preferably 10,000 to 100,000, based on the weight average molecular weight. Further, the number average molecular weight is preferably from 1,000 to 250,000, more preferably from 2,500 to 150,000, still more preferably from 5,000 to 50,000.
The content of the specific polymer in the liquid crystal alignment agent of the present invention is preferably from 2 to 10% by mass, more preferably from 3 to 8% by mass, based on the liquid crystal alignment agent.
In the liquid crystal alignment agent of the present invention, in addition to the specific polymer, a polylysine which is a reactant of any tetracarboxylic acid derivative component and any diamine component may be contained.
In addition, when the liquid crystal alignment agent contains the polyamic acid, the ratio thereof is preferably from 10 to 900 parts by mass, more preferably from 25 to 700 parts by mass, per 100 parts by mass of the polyimine.

All of the polymer components in the liquid crystal alignment agent of the present invention may be mixed with other polymers. Other examples of the polymer include a cellulose polymer, an acrylic polymer, a methacrylic polymer, polystyrene, polyamine, polyoxyalkylene, and the like. The content of the other polymer is preferably from 0.5 to 15 parts by mass, more preferably from 1 to 10 parts by mass, per 100 parts by mass of the total of the polyimine or the polyamic acid.

The concentration of the polymer of the liquid crystal alignment agent used in the present invention can be appropriately changed depending on the setting of the thickness of the coating film to be formed, and a uniform and defect-free coating film is formed, and it is preferably 1% by weight or more. The viewpoint of preservation stability is preferably 10% by weight or less.

The solvent in the liquid crystal alignment agent of the present invention is preferably a solvent (also referred to as a good solvent) for dissolving the polyimide precursor and the polyimide, or a coating film for the liquid crystal alignment film when the liquid crystal alignment agent is applied. Solvent for surface or surface smoothness (also known as poor solvent). Specific examples of other solvents are listed below, but are not limited thereto.

Specific examples of the good solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-butyl-2-pyrrolidone, γ-butyrolactone, and γ-pentyl Lactone, 1,3-dimethylimidazolidinone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylammonium , methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropane decylamine or 4-hydroxy-4-methyl-2-pentanone.
Specific examples of the poor solvent include 1-butoxy-2-propanol, 2-butoxy-1-propanol, 2-propoxyethanol, and 2-(2-propoxyethoxy)ethanol. , 1-propoxy-2-propanol ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol , 2-methyl-1-butanol, isoamyl alcohol, tert-pentanol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2 -methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1 -hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1,2-ethanediol, 1,2-propanediol, 1,3- Propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4 - pentanediol, 2-ethyl-1,3-hexanediol, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl Ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2- Pentanone, 3-pentanone, 2-hexanone 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate , ethylene glycol diacetate, propyl carbonate, ethyl carbonate, 2-(methoxymethoxy)ethanol, butyl cyanidin, ethylene glycol monoisoamyl ether, ethylene glycol Hexyl ether, 2-(hexyloxy)ethanol, furan methanol, diethylene glycol, propylene glycol, 1-(butoxyethoxy)propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol Methyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate , ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, propylene glycol diacetate, diisoamyl ether, diethylene glycol monobutyl ether Acid ester, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, Methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, B Acid propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3 - ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, lactic acid N-butyl ester, isoamyl lactate, diisobutyl ketone, ethyl carbitol, and the like.
Further, as the poor solvent, a solvent represented by the following formula is preferably used.

R _{24 and} R ₂₅ are each independently a linear or branched alkyl group having 1 to 8 carbon atoms. However, R ₂₄ + R ₂₅ is an integer greater than 3.
When the solubility of the polyimine precursor and the polyimine contained in the liquid crystal alignment agent in the solvent is high, the poor solvent is preferably represented by the following [D-1] to the formula [D-3]. Solvent.

In the formula [D-1], D ¹ represents an alkyl group having 1 to 3 carbon atoms, and in the formula [D-2], D ² represents an alkyl group having 1 to 3 carbon atoms, and in the formula [D-3], D ³ It represents an alkyl group having 1 to 4 carbon atoms.

Further, the liquid crystal alignment agent of the present invention may further contain a crosslinkable compound having an epoxy group, an isocyanate group, an oxetanyl group or a cyclic carbonate group; and having a terminal group selected from a hydroxyl group, a hydroxyalkyl group and a lower alkoxy group. A crosslinkable compound having at least one substituent of the group of alkyl groups or a crosslinkable compound having a polymerizable unsaturated bond.

As such a crosslinkable compound, various known compounds can be used depending on the purpose. Preferred for use are the following compounds.

The content of the crosslinkable compound is preferably from 0.1 to 150 parts by mass based on 100 parts by mass of the total polymer component. Among them, the effect of exhibiting the target in order to carry out the crosslinking reaction is preferably 0.1 to 100 parts by mass, more preferably 1 to 50 parts by mass.

The liquid crystal alignment agent of the present invention may contain a compound which improves the uniformity of the film thickness or the surface smoothness of the liquid crystal alignment film when the liquid crystal alignment agent is applied.

Examples of the compound which improves the uniformity of the film thickness of the liquid crystal alignment film or the surface smoothness include a fluorine-based surfactant, a polyfluorene-based surfactant, and a nonionic surfactant.
The amount of the surfactant to be used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, based on 100 parts by mass of all the polymer components contained in the liquid crystal alignment agent.
Further, the decane coupling agent for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate or the yttrium imidization efficiency by heating the polyimide precursor in the case of firing the coating film may be preferably carried out. The purpose of the imidization promoter and the like.

<Liquid alignment film, liquid crystal display element>
The liquid crystal alignment film of the present invention is a film obtained by applying the liquid crystal alignment agent onto a substrate, drying, and baking. The substrate to which the liquid crystal alignment agent of the present invention is applied is not particularly limited as long as it is a substrate having high transparency, and a plastic substrate such as a glass substrate, a tantalum nitride substrate, an acrylic substrate or a polycarbonate substrate can be used. At this time, when a substrate for forming an ITO electrode or the like for driving a liquid crystal is used, the viewpoint of simplification of the process is preferable. Further, in the reflective liquid crystal display device, an opaque object such as a germanium wafer may be used as the single-sided substrate. In this case, a material such as aluminum that reflects light may be used as the electrode.

The coating method of the liquid crystal alignment agent is generally carried out in the industry by screen printing, lithography, flexographic printing or ink jet method, and other coating methods are known as a dipping method and a roll coater. Method, slit coater method, rotator method or spray method.

After the liquid crystal alignment agent is applied onto the substrate, the solvent can be evaporated by a heating means such as a hot plate, a heat cycle type oven, or an IR (infrared) type oven to form a liquid crystal alignment film. The drying and baking steps after the application of the liquid crystal alignment agent can be selected to any temperature and time. In general, in order to sufficiently remove the solvent contained, it can be calcined at 50 to 120 ° C for 1 to 10 minutes, and then baked at 150 to 300 ° C for 5 to 120 minutes. When the thickness of the liquid crystal alignment film after firing is too small, the reliability of the liquid crystal display element may be lowered. Therefore, it is preferably 5 to 300 nm, more preferably 10 to 200 nm.

The liquid crystal alignment agent of the present invention can be subjected to alignment treatment by rubbing treatment or photo-alignment treatment after being applied and fired on a substrate, and is used as a liquid crystal alignment film in the case of vertical alignment use or the like without alignment treatment. . A known method or apparatus can be used for the alignment treatment of the rubbing treatment or the photo-alignment treatment.
As an example of a method of fabricating a liquid crystal cell, a liquid crystal display device having a passive matrix structure will be described as an example. Further, a liquid crystal display element having an active matrix structure of a switching element such as a TFT (Thin Film Transistor) may be provided in each pixel portion constituting the image display.

Specifically, a substrate made of a transparent glass is prepared, and a common electrode is provided on one of the substrates, and a segment electrode is provided on the other substrate. Such electrodes can be, for example, ITO electrodes, patterned in such a manner as to display a desired image. Next, an insulating film is provided on each of the substrates so as to cover the common electrode and the segment electrodes. The insulating film may be, for example, a film of SiO ₂ -TiO ₂ formed by a sol-gel method.

Next, a liquid crystal alignment film is formed on each of the substrates, and the other substrate is superimposed on one of the substrates so that the liquid crystal alignment film faces face each other, and the periphery is sealed with a sealant. In order to control the gap of the substrate, a spacer is usually mixed in advance in the sealant, and it is preferable that a spacer for controlling the gap of the substrate is dispersed in advance in the in-plane portion where the sealant is not provided. In one part of the sealant, an opening portion through which the liquid crystal can be externally filled is provided in advance. Next, the liquid crystal material is injected into the space surrounded by the two substrates and the sealant by the opening provided in the sealant, and then the opening is sealed with an adhesive. The injection can be performed by a vacuum injection method or a method of utilizing a capillary phenomenon in the atmosphere. The liquid crystal material may be any of a positive liquid crystal material or a negative liquid crystal material, preferably a negative liquid crystal material. Next, the setting of the polarizing plate is performed. Specifically, a pair of polarizing plates are attached to the surface of the two substrates opposite to the liquid crystal layer.

[Examples]

The present invention will be specifically described below by way of examples and the like, but the present invention is not limited to the examples. Further, the abbreviations of the compound and the solvent are as follows.
NMP: N-methyl-2-pyrrolidone
GBL: γ-butyrolactone
BCS: Butyl cypress
DA-1~DA-12, CA-1~CA-6: a compound represented by the following structural formula.
AD-1: 3-glycidoxypropyltriethoxydecane
AD-2: a compound represented by the following structural formula.

<viscosity>
In the synthesis example, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL, a conical rotor TE-1 (1° 34', R24), and a temperature. Measured at 25 ° C.

<Measurement of imidization ratio of polythenimine>
The ruthenium imidization ratio of the polyimine in the synthesis example was measured as follows. 30 mg of polyimine powder was placed in an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube standard, f5 (manufactured by Kusano Scientific Co., Ltd.)), and dimethyl-hydrazine (DMSO-d6, 0.05% by mass TMS (DMSO-d6) was added. Tetramethyl decane) (0.53 ml), ultrasonic waves were applied to completely dissolve. This solution was measured for proton NMR at 500 MHz by an NMR measuring machine (JNW-ECA500) (manufactured by JEOL Ltd.). The imidization ratio of ruthenium is determined by using protons from the unaltered structure before and after imidization as the reference proton, and the peak integral value of the proton is used, and the NH derived from proline is present in the vicinity of 9.5 ppm to 10.0 ppm. The base proton peak integral value is obtained by the following formula.

Yttrium imidation rate (%) = (1 - α · x / y) × 100

In the above formula, x is the integral value of the proton peak derived from the NH group of proline, y is the peak integral value of the reference proton, and α is the case of polyproline (the imidization ratio is 0%) with respect to 醯The ratio of the number of reference protons in one of the NH protons of the amine acid.

(Synthesis Example 1)
In a separable flask of 7 L with a stirring device and a nitrogen introduction tube, DA-1 225 g (3770 mmol), DA-2 167 g (419 mmol), DA-3 117 g (210 mmol) were weighed, and NMP 3130 g was added and sent. The mixture was stirred and dissolved by nitrogen. While stirring the diamine solution under water cooling, 204 g (910 mmol) of CA-1 was added, and 616 g of NMP was further added thereto, and the mixture was stirred at 40 ° C for 6 hours under a nitrogen atmosphere. Furthermore, 79.0 g (402 mmol) of CA-2 was further added, and 709 g of NMP was further added, and the mixture was stirred at 23 ° C for 2 hours under a nitrogen atmosphere to obtain a polyamine acid solution (viscosity: 270 mPa·s) PAA-B1.
In a 2 L Erlenmeyer flask equipped with a stirrer, 400 g of the polylysine solution was added, and 350 g of NMP, 32.4 g of acetic anhydride, and 8.39 g of pyridine were added, and the mixture was stirred at room temperature for 30 minutes, and then reacted at 55 ° C for 4 hours. . The reaction solution was poured into 2770 g of methanol, and the resulting precipitate was filtered. The precipitate was washed with methanol, and then dried under reduced pressure at a temperature of 80 ° C to obtain a powder of polyimine (yield: 87%).
Further, 40.0 g of the powder of the polyimine was placed in a 500 mL Erlenmeyer flask in which a stirrer was placed, and 293 g of NMP was added thereto, and the mixture was stirred at 70 ° C for 24 hours to be dissolved to obtain a solution of polyimine. A1.

(Synthesis Example 2)
In a 100 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-1 5.62 g (19.2 mmol), DA-2 4.18 g (10.5 mmol), and DA-3 2.92 g (5.24 mmol) were weighed and added. NMP 54.3 g was stirred and dissolved while feeding nitrogen. While stirring the diamine solution under water cooling, 4.50 g (22.7 mmol) of CA-3 was added, and 15.5 g of NMP was further added thereto, and the mixture was stirred at 50 ° C for 1 hour under a nitrogen atmosphere. Further, 2.26 g (11.5 mmol) of CA-2 was added, and 6.80 g of NMP was further added, and the mixture was stirred at 23 ° C for 2 hours under a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 1300 mPa·s).
In a 100 mL Erlenmeyer flask in which a stirrer was placed, 27.0 g of the polylysine solution was added, and 18.0 g of NMP, 2.96 g of acetic anhydride, and 0.766 g of pyridine were added, and the mixture was stirred at room temperature for 30 minutes, and then reacted at 55 ° C. 3 hours. The reaction solution was poured into 170 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol, and then dried under reduced pressure at a temperature of 80 ° C to obtain a powder of polyimine (yield: 86%).
Further, in a 500 mL Erlenmeyer flask in which a stirrer was placed, 4.00 g of the powder of the polyimine was taken, 29.3 g of NMP was added, and the mixture was stirred at 70 ° C for 24 hours to be dissolved to obtain a solution of polyimine. -A2.

(Synthesis Example 3)
In a 100 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-1 5.62 g (19.2 mmol), DA-2 4.18 g (10.5 mmol), and DA-3 2.92 g (5.24 mmol) were weighed and added. NMP 50.9 g was stirred and dissolved while feeding nitrogen. While the diamine solution was stirred under water cooling, 4.50 g (22.7 mmol) of CA-3 was added, and 18.0 g of NMP was further added thereto, and the mixture was stirred at 50 ° C for 1 hour under a nitrogen atmosphere. Further, 2.63 g (11.7 mmol) of CA-1 was added, and 9.70 g of NMP was further added, and the mixture was stirred at 40 ° C for 2 hours under a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 1180 mPa·s).
25.0 g of the polyamine acid solution was placed in a 100 mL Erlenmeyer flask in which a stirrer was placed, and 8.33 g of NMP, 2.96 g of acetic anhydride, and 0.766 g of pyridine were added, and the mixture was stirred at room temperature for 30 minutes, and then reacted at 55 ° C. 3 hours. The reaction solution was poured into 170 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol, and then dried under reduced pressure at a temperature of 80 ° C to obtain a powder of polyimine (yield: 86%).
Further, in a 500 mL Erlenmeyer flask in which a stirrer was placed, 4.00 g of the powder of the polyimine was taken, 29.3 g of NMP was added, and the mixture was stirred at 70 ° C for 24 hours to be dissolved to obtain a solution of polyimine. -A3.

(Synthesis Example 4)
In a 100 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-1 4.82 g (16.4 mmol), DA-2 3.58 g (8.98 mmol), and DA-3 2.50 g (4.49 mmol) were weighed and added. NMP 53.3g was stirred and dissolved while feeding nitrogen. While stirring the diamine solution under water cooling, 4.96 g (22.1 mmol) of CA-1 was added, and 19.3 g of NMP was further added thereto, and the mixture was stirred at 50 ° C for 1 hour under a nitrogen atmosphere. Further, 1.50 g (5.99 mmol) of CA-4 was added, and 6.35 g of NMP was further added, and the mixture was stirred at 40 ° C for 15 hours under a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 427 mPa·s).
30.0 g of the polyacetic acid solution was placed in a 100 mL Erlenmeyer flask in which a stirrer was placed, and 15.0 g of NMP, 2.85 g of acetic anhydride, and 0.737 g of pyridine were added thereto, and the mixture was stirred at room temperature for 30 minutes, and then reacted at 55 ° C. 3 hours. The reaction solution was poured into 170 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol, and then dried under reduced pressure at a temperature of 80 ° C to obtain a powder of polyimine (yield: 84%).
Further, in a 500 mL Erlenmeyer flask in which a stirrer was placed, 4.00 g of the powder of the polyimine was taken, 29.3 g of NMP was added, and the mixture was stirred at 70 ° C for 24 hours to be dissolved to obtain a solution of polyimine. -A4.

(Synthesis Example 5)
In a 100 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-1 2.89 g (9.88 mmol), DA-2 3.94 g (9.89 mmol), DA-3 2.75 g (4.94 mmol), DA were weighed. -4 2.01 g (8.22 mmol), 49.5 g of NMP was added, and it was stirred and dissolved by sending nitrogen. While the diamine solution was stirred under water cooling, 4.25 g (21.4 mmol) of CA-3 was added, and 14.7 g of NMP was further added thereto, and the mixture was stirred at 50 ° C for 1 hour under a nitrogen atmosphere. Further, CA-2 2.04 g (10.4 mmol) was added, and 6.96 g of NMP was further added, and the mixture was stirred at 23 ° C for 2 hours under a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 1170 mPa·s).
In a 100 mL Erlenmeyer flask in which a stirrer was placed, 25.0 g of the polylysine solution was added, 16.6 g of NMP, 2.81 g of acetic anhydride, and 0.728 g of pyridine were added, and the mixture was stirred at room temperature for 30 minutes, and then reacted at 55 ° C. 3 hours. The reaction solution was poured into 160 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol, and then dried under reduced pressure at a temperature of 80 ° C to obtain a powder of polyimine (yield: 82%).
Further, in a 500 mL Erlenmeyer flask in which a stirrer was placed, 4.00 g of the powder of the polyimine was taken, 29.3 g of NMP was added, and the mixture was stirred at 70 ° C for 24 hours to be dissolved to obtain a solution of polyimine. -A5.

(Synthesis Example 6)
In a 300 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-2 6.33 g (15.8 mmol), DA-3 4.42 g (7.94 mmol), and DA-8 8.52 g (29.1 mmol) were weighed and added. 150 g of NMP was stirred and dissolved while feeding nitrogen. While stirring the diamine solution under water cooling, 7.72 g (34.4 mmol) of CA-1 was added, and 10.0 g of NMP was further added thereto, and the mixture was stirred at 40 ° C for 6 hours under a nitrogen atmosphere. Further, 3.38 g (17.2 mmol) of CA-2 was added, and 10.0 g of NMP was further added, and the mixture was stirred at 23 ° C for 2 hours in a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 190 mPa·s).
150 g of the solution of the polyaminic acid was placed in a 500 mL Erlenmeyer flask in which a stirrer was placed, and 130 g of NMP, 12.1 g of acetic anhydride, and 3.13 g of pyridine were added, and the mixture was stirred at room temperature for 30 minutes, and then reacted at 55 ° C for 4 hours. . The reaction solution was poured into 1040 g of methanol, and the resulting precipitate was filtered. The precipitate was washed with methanol, and then dried under reduced pressure at a temperature of 80 ° C to obtain a powder of polyimine (yield: 81%).
Further, in a 500 mL Erlenmeyer flask in which a stirrer was placed, 4.00 g of the powder of the polyimine was taken, 29.3 g of NMP was added, and the mixture was stirred at 70 ° C for 24 hours to be dissolved to obtain a solution of polyimine. -A6.

(Synthesis Example 7)
In a 100 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-5 1.12 g (4.49 mmol), DA-6 1.49 g (7.47 mmol), and DA-7 0.590 g (2.97 mmol) were weighed and added. NMP 15.5g and GBL 15.5g were stirred and dissolved while feeding nitrogen. While stirring the diamine solution under water cooling, 1.15 g (5.86 mmol) of CA-2 was added, and 5.00 g of NMP and 5.00 g of GBL were further added, and the mixture was stirred at 25 ° C for 1 hour under a nitrogen atmosphere. Further, 2.60 g (8.83 mmol) of CA-5 was added, and 5.00 g of NMP and 5.00 g of GBL were further added, and the mixture was stirred at 50 ° C for 12 hours under a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 200 mPa·s) PAA- A1.

(Synthesis Example 8)
The polyamino acid solution PAA-B1 obtained in Synthesis Example 1 was dispensed into 30.0 g, 26.2 g of NMP, 2.44 g of acetic anhydride, and 0.630 g of pyridine were added, and the mixture was stirred at room temperature for 30 minutes, and then reacted at 40 ° C for 30 minutes. The reaction solution was poured into 150 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol, and then dried under reduced pressure at a temperature of 80 ° C to obtain a powder of polyimine (yield: 40%).
Further, in a 500 mL Erlenmeyer flask in which a stirrer was placed, 2.00 g of the powder of the polyimine was taken, 14.6 g of NMP was added, and the mixture was stirred at 70 ° C for 24 hours to be dissolved to obtain a solution of polyimine. -B1.

(Synthesis Example 9)
In a 200 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-1 8.04 g (27.5 mmol), DA-2 5.98 g (15.0 mmol), and DA-3 4.17 g (7.50 mmol) were weighed and added. 111 g of NMP was stirred and dissolved while feeding nitrogen. While the diamine solution was stirred under water cooling, 7.29 g (32.5 mmol) of CA-1 was added, and 22.0 g of NMP was further added thereto, and the mixture was stirred at 40 ° C for 6 hours under a nitrogen atmosphere. Further, 3.16 g (14.5 mmol) of CA-6 was added, and 28.5 g of NMP was further added, and the mixture was stirred at 50 ° C for 12 hours under a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 280 mPa·s).
In a 300 mL Erlenmeyer flask in which a stirrer was placed, 100 g of the polylysine solution was added, and 87.5 g of NMP, 8.02 g of acetic anhydride, and 2.07 g of pyridine were added, and the mixture was stirred at room temperature for 30 minutes, and then reacted at 55 ° C. hour. The reaction solution was poured into 700 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol, and then dried under reduced pressure at a temperature of 80 ° C to obtain a powder of polyimine (yield: 82%).
Further, 10.0 g of the powder of the polyimine was taken in a 500 mL Erlenmeyer flask in which a stirrer was placed, and 73.3 g of NMP was added thereto, and the mixture was stirred at 70 ° C for 24 hours to be dissolved to obtain a solution of polyimine. -B2.

(Synthesis Example 10)
In a 100 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-8 5.62 g (19.3 mmol), DA-2 4.18 g (10.5 mmol), and DA-3 2.92 g (5.25 mmol) were weighed and added. NMP 54.3 g was stirred and dissolved while feeding nitrogen. While the diamine solution was stirred under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, and 15.5 g of NMP was further added thereto, and the mixture was stirred at 50 ° C for 1 hour under a nitrogen atmosphere. Further, 2.29 g (11.7 mmol) of CA-2 was added, and 8.30 g of NMP was further added, and the mixture was stirred at 23 ° C for 2 hours under a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 1210 mPa·s).
In the same manner as in Synthesis Example 2, the obtained polylysine was subjected to chemical hydrazine imidation to obtain a powder of polyimine (an imidization ratio: 83%), which was further dissolved in NMP to obtain a polyazide. Amine solution SPI-A7.

(Synthesis Example 11)
In a 100 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-9 5.62 g (19.3 mmol), DA-2 4.18 g (10.5 mmol), and DA-3 2.92 g (5.25 mmol) were weighed and added. NMP 54.3 g was stirred and dissolved while feeding nitrogen. While the diamine solution was stirred under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, and 15.5 g of NMP was further added thereto, and the mixture was stirred at 50 ° C for 1 hour under a nitrogen atmosphere. Further, 2.33 g (11.9 mmol) of CA-2 was added, and 8.50 g of NMP was further added, and the mixture was stirred at 23 ° C for 2 hours under a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 900 mPa·s).
In the same manner as in Synthesis Example 2, the obtained polylysine was subjected to chemical hydrazine imidization to obtain a powder of polyimine (an imidization ratio: 80%), which was further dissolved in NMP to obtain a polyazide. Amine solution SPI-A8.

(Synthesis Example 12)
In a 100 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-10 7.09 g (19.3 mmol), DA-2 4.18 g (10.5 mmol), and DA-3 2.92 g (5.25 mmol) were weighed and added. 60.5 g of NMP was stirred and dissolved while feeding nitrogen. While stirring the diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, and 15.2 g of NMP was further added thereto, and the mixture was stirred at 50 ° C for 1 hour under a nitrogen atmosphere. Further, 2.25 g (11.5 mmol) of CA-2 was added, and 8.10 g of NMP was further added, and the mixture was stirred at 23 ° C for 2 hours under a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 1250 mPa·s).
In the same manner as in Synthesis Example 2, the obtained polylysine was subjected to chemical hydrazine imidization to obtain a powder of polyimine (an imidization ratio: 75%), which was further dissolved in NMP to obtain a polyazide. Amine solution SPI-A9.

(Synthesis Example 13)
In a 100 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-11 7.40 g (19.3 mmol), DA-2 4.18 g (10.5 mmol), and DA-3 2.92 g (5.25 mmol) were weighed and added. 61.8 g of NMP was stirred and dissolved while feeding nitrogen. While stirring the diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, and 15.2 g of NMP was further added thereto, and the mixture was stirred at 50 ° C for 1 hour under a nitrogen atmosphere. Further, 2.30 g (11.7 mmol) of CA-2 was added, and 8.20 g of NMP was further added, and the mixture was stirred at 23 ° C for 2 hours under a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 980 mPa·s).
In the same manner as in Synthesis Example 2, the obtained polylysine was subjected to chemical hydrazine imidization to obtain a powder of polyimine (an imidization ratio: 81%), which was further dissolved in NMP to obtain a polyazide. Amine solution SPI-A10.

(Synthesis Example 14)
In a 100 mL eggplant type flask equipped with a stirring device and a nitrogen introduction tube, DA-12 9.17 g (19.3 mmol), DA-2 4.18 g (10.5 mmol), and DA-3 2.92 g (5.25 mmol) were weighed and added. 69.4 g of NMP was stirred and dissolved while feeding nitrogen. While the diamine solution was stirred under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, and 14.8 g of NMP was further added thereto, and the mixture was stirred at 50 ° C for 1 hour under a nitrogen atmosphere. Further, 2.34 g (12.0 mmol) of CA-2 was added, and 8.30 g of NMP was further added, and the mixture was stirred at 23 ° C for 2 hours under a nitrogen atmosphere to obtain a solution of polylysine (viscosity: 1030 mPa·s).
In the same manner as in Synthesis Example 2, the obtained polylysine was subjected to chemical hydrazine imidation to obtain a powder of polyimine (an imidization ratio: 83%), which was further dissolved in NMP to obtain a polyazide. Amine solution SPI-A11.

(Synthesis Example 15)
In a 100 mL Erlenmeyer flask in which a stirrer was placed, 30.0 g of a solution of the polyamic acid obtained in Synthesis Example 2 was added, and 0.470 g of di-tert-butyl dicarbonate was added thereto, followed by a reaction at 40 ° C for 12 hours. Further, 20.0 g of NMP, 3.85 g of acetic anhydride, and 1.28 g of pyridine were added, and the mixture was stirred at room temperature for 30 minutes, and then reacted at 60 ° C for 4 hours. The reaction solution was poured into 220 g of methanol, and the resulting precipitate was filtered. The precipitate was washed with methanol, and then dried under reduced pressure at a temperature of 80 ° C to obtain a powder of polyimine (yield: 90%).
Further, in a 500 mL Erlenmeyer flask in which a stirrer was placed, 3.50 g of the powder of the polyimine was taken, and 25.6 g of NMP was added thereto, and the mixture was stirred at 70 ° C for 24 hours to be dissolved to obtain a solution of polyimine. -A12.

(Examples 1 to 15) and (Comparative Examples 1 to 3)
The solution obtained by mixing the solution of the polyamic acid obtained in Synthesis Examples 1 to 15 and the solution of polyimine was mixed at a ratio of the polymer 1 and the polymer 2 shown in the following table to become a solution. In the form of the composition shown in the following table, a NMP solution containing 1% by weight of NMP, GBL, BCS, and AD-1, and a NMP solution containing 10% by weight of AD-2 were added while stirring, and further stirred at room temperature for 2 hours. The liquid crystal alignment agents of Examples 1 to 15 and Comparative Examples 1 to 3 were obtained.

The liquid crystal cell 1 for evaluating the pretilt angle and the voltage holding ratio and the method for fabricating the liquid crystal cell 2 for evaluating the liquid crystal alignment are shown below.

[Production of Liquid Crystal Cell 1]
First, prepare a substrate with an electrode attached. The substrate is a glass substrate having a size of 30 mm × 40 mm and a thickness of 1.1 mm. An ITO electrode having a thickness of 35 nm was formed on the substrate, and the electrode was a strip pattern of 40 mm in length and 10 mm in width.
Next, the liquid crystal alignment agent was filtered through a filter having a pore size of 1.0 μm, and then applied by spin coating to the prepared electrode-attached substrate. After drying on a hot plate at 80 ° C for 2 minutes, the film was fired in an IR oven at 230 ° C for 20 minutes to form a coating film having a film thickness of 100 nm, thereby obtaining a substrate having a liquid crystal alignment film. The liquid crystal alignment film was rubbed with a rubbing cloth (roller diameter: 120 mm, number of rotations of the roller: 1000 rpm, moving speed: 20 mm/sec, press-in length: 0.4 mm), and then irradiated for 1 minute in pure water for ultrasonication. After washing, the air was removed to remove water droplets, and then dried at 80 ° C for 10 minutes to obtain a substrate with a liquid crystal alignment film. Two substrates having the liquid crystal alignment film were prepared, and a spacer of 4 μm was spread on one of the liquid crystal alignment film surfaces, and then the sealant was printed thereon, and the other substrate was reversed in the rubbing direction. After the film faces are bonded to each other, the sealant is cured to form an empty unit cell. Liquid crystal MLC-3019 (manufactured by Merck Co., Ltd.) was injected into the empty cell by a vacuum injection method, and the injection port was sealed to obtain a liquid crystal cell. Thereafter, the obtained liquid crystal cell was heated at 120 ° C for 1 hour, and left at 23 ° C for each evaluation.

[Production of Liquid Crystal Cell 2]
A glass substrate with an electrode of 30 mm × 35 mm and a thickness of 0.7 mm was prepared. An IZO electrode having a full-surface pattern constituting the counter electrode was formed on the substrate as the first layer. On the counter electrode of the first layer, a SiN (tantalum nitride) film formed by a CVD method is formed as a second layer. The SiN film of the second layer has a film thickness of 500 nm and functions as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning an IZO film is disposed, and as the third layer, two pixels of the first pixel and the second pixel are formed. The size of each pixel is 10 mm in length and 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer has a comb-like shape in which a plurality of electrode elements having a "ㄑ" shape in which the central portion is curved as shown in FIG. 3 described in Japanese Laid-Open Patent Publication No. 2014-77845. The width of each electrode element in the short-side direction was 3 μm, and the interval between the electrode elements was 6 μm. The pixel electrodes forming the respective pixels are formed by a plurality of arrangement of electrode elements having a "ㄑ" shape in which the central portion is curved. Therefore, the shape of each pixel is not rectangular, but is provided in the central portion in the same manner as the electrode elements. The shape of the curve is similar to the shape of the bold word "ㄑ". Further, each of the pixels is vertically divided by a curved portion at the center thereof, and has a first region on the upper side of the curved portion and a second region on the lower side.

When the first region and the second region of each pixel are compared, the direction in which the electrode elements constituting the pixel electrodes are formed is different. In other words, when the rubbing direction of the liquid crystal alignment film is used as a reference, in the first region of the pixel, the electrode element of the pixel electrode is formed at an angle of +10° (clockwise), and is in the form of a pixel. In the region 2, the electrode elements of the pixel electrodes are formed at an angle of -10° (clockwise). Further, in the first region and the second region of each pixel, the liquid crystal induced in the plane of the substrate by the voltage applied between the pixel electrode and the counter electrode is applied (in-plane switching, in-plane switching). The direction is formed in the opposite direction to each other.

Next, the liquid crystal alignment agent was filtered through a filter having a pore size of 1.0 μm, and then each of the glass-attached substrate and the glass having the ITO film formed on the back surface of the counter substrate and having a columnar spacer having a height of 4 μm were spin-coated. Substrate. Subsequently, the film was dried on a hot plate at 80 ° C for 2 minutes, and then fired at 230 ° C for 20 minutes to obtain a polyimide film having a film thickness of 60 nm on each substrate. The liquid crystal alignment film was rubbed with a crepe (roller diameter: 120 mm, number of rotations of the roller: 500 rpm, moving speed: 30 mm/sec, press-in length: 0.3 mm), and then irradiated for 1 minute in pure water for washing. After the water was removed by air blowing, it was dried at 80 ° C for 10 minutes to obtain a substrate with a liquid crystal alignment film.
Two kinds of substrates having the liquid crystal alignment film described above were used, and the respective rubbing directions were combined in antiparallel to leave a liquid crystal injection port, and the periphery was sealed to prepare an empty cell having a cell gap of 3.8 μm. After the vacuum cell was vacuum-injected into the liquid crystal MLC-3019 (manufactured by Merck Co., Ltd.) at normal temperature, the injection port was sealed to serve as an antiparallel alignment liquid crystal cell. The obtained liquid crystal cell system constitutes an FFS mode liquid crystal display element. Thereafter, the liquid crystal cell was heated at 120 ° C for 1 hour, and left at 23 ° C for use in the following evaluations.

<pretilt angle>
The pretilt angle in the above liquid crystal cell 1 was evaluated using an AxoScan Mueller matrix polarimeter manufactured by Optometrics.

<voltage retention rate>
The liquid crystal cell 1 was applied with a voltage of 1 V for 60 μsec at a temperature of 60 ° C, and the voltage after 50 msec was measured to determine how long the voltage can be maintained as a voltage holding ratio.

<Evaluation of liquid crystal alignment>
Using the above liquid crystal cell 2, an alternating voltage of 9 VPP was applied at a frequency of 30 Hz for 170 hours under a constant temperature environment of 60 °C. Thereafter, a state in which the pixel electrode of the liquid crystal cell and the counter electrode are short-circuited is placed at room temperature for one day.

After being placed at 23 ° C, the liquid crystal cell is placed between two polarizing plates arranged orthogonally with the polarization axis, and the backlight is turned on before the voltage is applied, and the arrangement angle of the liquid crystal cell is adjusted. To minimize the brightness of transmitted light. Then, the rotation angle when the liquid crystal cell is rotated from the angle at which the second region of the first pixel is the darkest to the darkest angle of the first region is calculated, and the angle Δθ1 is similarly applied to the second pixel. The second region and the first region are compared, and the angle Δθ2 is calculated. The average value of Δθ1 and Δθ2 is the angle Δθ of the liquid crystal cell, and the smaller the value, the better the liquid crystal alignment is evaluated.

The results of the pretilt angle, the voltage holding ratio, and the angle Δθ of the liquid crystal cell as described above for the liquid crystal display elements using the liquid crystal alignment agents of the above Examples 1 to 15 and Comparative Examples 1 to 3 are shown in The following table.

It is understood that the liquid crystal display element using the liquid crystal alignment agent of the embodiment of the present invention has a low pretilt angle, a high voltage holding ratio, and a good liquid crystal alignment property.

[Industrial availability]

By using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film which satisfies various characteristics required for a liquid crystal alignment film and imparts a low pretilt angle of 1 degree or less can be obtained.

Claims (18)

A liquid crystal alignment agent containing a reactant of a tetracarboxylic dianhydride derivative component and a diamine component, which are selected from at least one selected from the group consisting of a free aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride. a liquid crystal alignment agent of polyimine, wherein the diamine component contains at least one selected from the diamines of the following formula [A], and the ruthenium imidization ratio of the polyimine is 70% or more; Wherein P ₁ and P ₂ are a phenyl group or a biphenyl group, and the hydrogen on the aromatic ring may be substituted with a methyl group or a fluorine group; further, Q is a divalent organic group, and n1 and n2 are integers of 0 to 5 However, when at least one of n1 and n2 is 0, Q is an oxygen atom. The liquid crystal alignment agent of claim 1, wherein the diamine of the above formula [A] is at least one selected from the following formulas [A-1] to [A-6]; . The liquid crystal alignment agent of claim 1, wherein the diamine of the above formula [A] is 40% to 80% of the total diamine component. The liquid crystal alignment agent of claim 2, wherein the diamine of the above formula [A] is 40% to 80% of the total diamine component. The liquid crystal alignment agent of any one of Claims 1 to 4, wherein the aforementioned diamine component further comprises a diamine having a structure of the following formula (6) in its structure; In the above formula (6), D is a heat-releasing group which is substituted at 150 to 230 ° C and is substituted with a hydrogen atom. The liquid crystal alignment agent of claim 5, wherein the diamine having the structure of the formula (6) is at least one selected from the following diamines; Wherein n is an integer from 1 to 12. The liquid crystal alignment agent according to any one of Claims 1 to 4, wherein the aliphatic tetracarboxylic dianhydride and the alicyclic tetracarboxylic dianhydride are represented by the following formula (4); Wherein X ₁ is a structure selected from the following structures; . The liquid crystal alignment agent of claim 5, wherein the aliphatic tetracarboxylic dianhydride and the alicyclic tetracarboxylic dianhydride are represented by the following formula (4); Wherein X ₁ is a structure selected from the following structures; . The liquid crystal alignment agent according to any one of Claims 1 to 4, or the Claim 6 or Claim 8, which further comprises a poly-proline which is a reactant of a tetracarboxylic dianhydride derivative and a diamine. The liquid crystal aligning agent of claim 5, which further comprises a polylysine which is a reactant of a tetracarboxylic dianhydride derivative and a diamine. The liquid crystal aligning agent of claim 7, which further comprises a polylysine which is a reactant of a tetracarboxylic dianhydride derivative and a diamine. The liquid crystal aligning agent of claim 9, which further comprises a polyamic acid which is a reactant of a tetracarboxylic dianhydride derivative and a diamine. A liquid crystal alignment film obtained by the liquid crystal alignment agent according to any one of claims 1 to 4, 6, 8, and 10 to 12. A liquid crystal alignment film obtained by the liquid crystal alignment agent of claim 5. A liquid crystal alignment film obtained by the liquid crystal alignment agent of claim 7. A liquid crystal alignment film obtained by the liquid crystal alignment agent of claim 9. A liquid crystal display element comprising the liquid crystal alignment film of claim 13. A liquid crystal display element comprising the liquid crystal alignment film according to any one of claims 14 to 16.