WO2013146890A1

WO2013146890A1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: WO2013146890A1
Application number: PCT/JP2013/059014
Authority: WO
Inventors: 裕充松本
Original assignee: 日産化学工業株式会社
Priority date: 2012-03-29
Filing date: 2013-03-27
Publication date: 2013-10-03
Also published as: TWI600683B; KR102009543B1; CN104380188A; JPWO2013146890A1; KR20140141689A; TW201400528A; CN104380188B; JP6183616B2

Abstract

This liquid crystal alignment agent comprises: a polyimide soluble in a solvent and using a diamine compound represented by formula (1) in at least a portion of the material thereof; a polyamic acid; and a solvent. (In formula (1), X¹ is an oxygen atom or a sulfur atom, Y¹ is a single bond, -O-, -S-, or -COO-* (wherein the bonding hand with the "*" bonds with R¹), and R¹ is a C_1-3 alkylene group.)

Description

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

The present invention relates to a liquid crystal aligning agent used when producing a liquid crystal aligning film, a liquid crystal aligning film using the same, and a liquid crystal display element.

Liquid crystal display elements used for liquid crystal televisions and liquid crystal displays are now widely used as thin and light display devices. As a liquid crystal alignment film for aligning liquid crystals, a polyimide precursor such as polyamic acid (also referred to as polyamic acid) or a liquid crystal alignment agent mainly composed of a solution of soluble polyimide is applied to a glass substrate or the like, and baked. A liquid crystal alignment film is mainly used.

As liquid crystal display elements are further increased in size and definition, liquid crystal alignment films have excellent liquid crystal alignment properties and liquid crystal molecules with respect to the substrate surface due to demands such as reduction of contrast reduction and afterimage phenomenon. In addition to stable expression and control of orientation tilt angle (pretilt angle), high voltage holding ratio, suppression of afterimages generated by AC drive, low residual charge when DC voltage is applied, residual charge accumulated by DC voltage Electrical characteristics such as rapid relaxation are becoming increasingly important, and various studies have been conducted to improve these characteristics.

For example, in order to improve pretilt angle characteristics, voltage holding ratio, and the like, a liquid crystal aligning agent in which a soluble polyimide is mixed with polyamic acid has been proposed (see Patent Document 1).

JP-A-8-220541

However, such a liquid crystal aligning agent has a problem that it tends to be whitened due to moisture absorption when applied on a substrate or the like. Moreover, the liquid crystal alignment film formed using such a liquid crystal aligning agent also has the problem that the electrical property is easy to deteriorate by the backlight irradiation of a liquid crystal display element.

An object of the present invention is to solve the above-described problems of the prior art, and to provide a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element that are suppressed in whitening and have excellent backlight resistance.

As a result of earnest research, the present inventors have found that a liquid crystal aligning agent containing a soluble polyimide using a diamine compound having a specific structure as a raw material and a polyamic acid is extremely effective for achieving the above-described problem. The headline and the present invention were completed.

That is, the present invention has the following gist.
1. The liquid crystal aligning agent characterized by including the solvent soluble polyimide which used the diamine compound represented by following formula (1) for at least one part of a raw material, a polyamic acid, and a solvent.

(In the formula (1), X ¹ is an oxygen atom or a sulfur atom, and Y ¹ is a single bond, —O—, —S— or —COO— * (where a bond marked with “*” is R ¹ And R ¹ is an alkylene group having 1 to 3 carbon atoms.)

2. 2. The liquid crystal aligning agent according to 1, wherein the diamine compound represented by the formula (1) is 10 to 90 mol% in the diamine component of the solvent-soluble polyimide raw material.

3. X ¹ in the formula (1) is, the liquid crystal alignment agent according to 1 or 2, characterized in that an oxygen atom.

4). 4. The liquid crystal aligning agent according to any one of 1 to 3, wherein the solvent-soluble polyimide uses a diamine compound represented by the following formula (2) as a part of a raw material.

(In Formula (2), R ² is a single bond, —O— or a divalent organic group, X ² , X ³ and X ⁴ are each independently a divalent benzene ring or a cyclohexane ring; , Q, and r are each independently an integer of 0 or 1, and R ³ is a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or a monovalent organic group having 12 to 25 carbon atoms having a steroid skeleton. .)

5. A liquid crystal alignment film obtained by using the liquid crystal aligning agent according to any one of 1 to 4.

A liquid crystal display element comprising the liquid crystal alignment film according to 6.5.

The liquid crystal aligning agent of the present invention is suppressed in whitening and has excellent backlight resistance. Therefore, for example, a liquid crystal alignment film having excellent uniformity and transparency can be produced even if the standing time after application to a substrate or the like is increased. In addition, since this liquid crystal alignment film has excellent backlight resistance, a decrease in electrical characteristics such as voltage holding ratio (VHR) due to backlight irradiation is suppressed, and a liquid crystal display element having excellent electrical characteristics is provided. can do.

The present invention is described in detail below.
The liquid crystal aligning agent of this invention contains the solvent soluble polyimide which used the diamine compound represented by the said Formula (1) for at least one part of a raw material, a polyamic acid, and a solvent. The liquid crystal alignment agent is a solution for producing a liquid crystal alignment film, and the liquid crystal alignment film is a film for aligning liquid crystals in a predetermined direction. Each component contained in the liquid crystal aligning agent of this invention is explained in full detail below.

<Solvent-soluble polyimide using the diamine compound represented by the above formula (1) as at least a part of the raw material>
The solvent-soluble polyimide is a polyimide that dissolves in the solvent contained in the liquid crystal aligning agent, and is obtained by polymerizing a diamine component with at least one tetracarboxylic acid component selected from tetracarboxylic acid and derivatives thereof. It is obtained by imidizing a polyimide precursor such as polyamic acid or polyamic acid ester. And the polyimide which the liquid crystal aligning agent of this invention contains is a polymer synthesize | combined using the diamine compound represented by the said Formula (1) as this diamine component which is a raw material.

As described above, in the above formula (1), X ¹ is an oxygen atom or a sulfur atom, and is preferably an oxygen atom. Y ¹ is a single bond, —O—, —S—, or —COO— * (where a bond marked with “*” is bonded to R ¹ ), and is preferably a single bond. R ¹ is an alkylene group having 1 to 3 carbon atoms, preferably an alkylene group having 2 carbon atoms. In addition, a preferable combination of X ¹ , Y ¹ and R ¹ is that X ¹ is an oxygen atom, Y ¹ is a single bond, and R ¹ is an alkylene group having 2 carbon atoms. As shown in Formula (1), in the diamine compound represented by Formula (1), two —Y ¹ —R ¹ — have a bilaterally symmetrical structure with a urea structure as the center.

Further, the bonding position of the _two amino groups (—NH ₂ ) in the above formula (1) is not limited. Specifically, for Y ¹ , 2, 3 position, 2, 4 position, 2, 5 position, 2, 6 position, 3, 4 position or 3, 5 position on the benzene ring, respectively. Position. Among these, from the viewpoint of reactivity when synthesizing the polymer, the 2,4 position, the 2,5 position, or the 3,5 position is preferable. Considering the ease in synthesizing the diamine compound, the positions 2, 4 or 2, 5 are more preferable.

In addition, the diamine compound represented by the above formula (1) used as a raw material for the solvent-soluble polyimide may be one kind or two or more kinds.

In addition, the diamine compound represented by the above formula (1) is preferably 10 to 90 mol%, more preferably 20 to 30 mol% in the total diamine component of the raw material of the solvent-soluble polyimide. In the present specification, unless otherwise specified, the ratio is based on the number of moles.

The method for synthesizing the diamine compound represented by the above formula (1) is not particularly limited, and for example, it can be synthesized by the method described below.

The diamine compound represented by the formula (1) is obtained by synthesizing a dinitro compound represented by the following formula (1A), further reducing the nitro group and converting it to an amino group. In formula (1A), R ¹ , Y ¹ and X ¹ have the same meaning as in formula (1). There is no particular limitation on the method for reducing the dinitro compound. For example, palladium-carbon, platinum oxide, Raney nickel, iron, tin chloride, platinum black, rhodium-alumina, or platinum sulfide carbon is used as a catalyst. Ethyl acetate, toluene, tetrahydrofuran There is a method of performing reduction by a reaction using hydrogen gas, hydrazine, hydrogen chloride, ammonium chloride or the like in a solvent such as dioxane or alcohol.

The synthesis method of the dinitro compound represented by the formula (1A) is not particularly limited, and any method can be used. For example, a method as shown in the following scheme (I) can be mentioned.

In Scheme (I), a dinitro compound represented by the formula (1A) is obtained by combining a nitrobenzene compound (α) and a (thio) carbonyl compound (generic name for a carbonyl compound and a thiocarbonyl compound) (β). It can be synthesized by reacting in a solvent in the presence of an alkali.

The above nitrobenzene compound in (alpha), ^{R 1} and ^{Y 1} are the same as equation (1), an amino group represented by NH ₂ may form a salt such as hydrochloride _(NH 2 · HCl) May be. Examples thereof include nitrobenzylamine or its hydrochloride, 2- (nitrophenyl) ethylamine or its hydrochloride, 3- (nitrophenyl) propylamine or its hydrochloride. Further, the substitution position of the nitro group on the benzene ring is appropriately selected from those at which the target diamine compound is obtained. In addition, the compound shown here is an example and is not specifically limited.

In the (thio) carbonyl compound (β), X ¹ is the same as in the formula (1), and Z is a monovalent or divalent organic group. Examples of the (thio) carbonyl compound (β) include phosgene, thiophosgene, diphenyl carbonate, diphenyl thiocarbonate, bis (nitrophenyl) carbonate, bis (nitrophenyl) thiocarbonate, dimethyl carbonate, dimethylthiocarbonate, diethyl carbonate, and diethyl. Examples thereof include thiocarbonate, ethylene carbonate, ethylene thiocarbonate, 1,1′-carbonylbis-1H-imidazole, and 1,1′-thiocarbonylbis-1H-imidazole. Further, carbon oxide (carbon monoxide or carbon dioxide) may be used instead of the carbonyl compound (β). In addition, the compound shown here is an example and is not specifically limited.

Examples of the alkali include basic organic compounds such as triethylamine, diisopropylethylamine and DMAP (4-N, N-dimethylaminopyridine), inorganic alkali compounds such as sodium hydroxide and potassium carbonate, and metal hydrides such as sodium hydride. Etc. In addition, the compound shown here is an example and is not specifically limited.

Organic solvents include solvents that do not affect the reaction, specifically, aromatic solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane and heptane, and halogen solvents such as dichloromethane and 1,2 dichloroethane. Solvents, ether solvents such as tetrahydrofuran and 1,4-dioxane, and aprotic polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide alone or in combination It can also be used. These use amounts are arbitrary.

Further, the solvent-soluble polyimide contained in the liquid crystal aligning agent of the present invention may use other diamine compounds other than the diamine compound represented by the above formula (1) as a raw material diamine component. Examples of other diamine compounds include compounds represented by the above formula (2). The diamine compound represented by the above formula (2) may be one type or two or more types.

As described above, in the above formula (2), R ² is a single bond, —O— or a divalent organic group, and preferably —O—. X ² , X ³ and X ⁴ are each independently a divalent benzene ring or cyclohexane ring, p, q and r are each independently an integer of 0 or 1, and r is preferably 0. . R ³ is a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or a monovalent organic group having 12 to 25 carbon atoms having a steroid skeleton, and is preferably an alkyl group having 12 to 18 carbon atoms. The alkyl group having 1 to 22 carbon atoms may be linear or branched.

The diamine compound represented by the above formula (2) contributes to increasing the pretilt angle of the liquid crystal (the tilt angle of the liquid crystal with respect to the liquid crystal alignment film). Examples of these diamine compounds include long-chain alkyl groups, A diamine having a perfluoroalkyl group, an aromatic cyclic group, an aliphatic cyclic group, a combination of these, a steroid skeleton group, or the like is preferable.

Although the preferred size of the pretilt angle varies depending on the mode, the pretilt angle is preferably selected by variously selecting the structure of the diamine compound represented by the above formula (2) and the proportion contained in the diamine component that is a raw material of the solvent-soluble polyimide. Can be obtained. For example, the diamine compound represented by the formula (2) is preferably 5 to 30 mol%, more preferably 10 to 15 mol% in the diamine component of the raw material of the solvent-soluble polyimide.

In the diamine compound represented by the formula (2), in the TN mode in which a relatively low pretilt angle of 3 to 5 ° is required, and the OCB mode in which a pretilt angle of 8 to 20 ° is required, the tilt expression ability is high. A relatively low structure is preferred.

As a structure having a relatively small tilting ability, R ² is preferably —O— or —NHCO — (— CONH—), wherein p is 0 to 1, q is 0 to 1, and r is preferably 0. And / or when q is 1, R ³ is preferably straight-chain alkyl having 1 to 12 carbon atoms, and when p = q = r = 0, R ³ is a straight-chain alkyl group having 10 to 22 carbon atoms or a steroid skeleton. A monovalent organic group selected from organic groups having 12 to 25 carbon atoms having Although the specific structure of the diamine compound represented by Formula (2) with small tilt expression ability is shown in Table 1, it is not limited to this.

In addition, other diamine compounds other than the diamine compound represented by the above formula (1) that may be contained in the diamine component of the raw material of the solvent-soluble polyimide of the present invention include p-phenylenediamine, 2, 3, 5, 6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene 2,5-diaminophenol, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'- Diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-di Toxi-4,4′-diaminobiphenyl, 3,3′-dihydroxy-4,4′-diaminobiphenyl, 3,3′-dicarboxy-4,4′-diaminobiphenyl, 3,3′-difluoro-4, 4'-biphenyl, 3,3'-trifluoromethyl-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3 ' -Diaminobiphenyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2'-diaminodiphenylmethane, 2,3'-diaminodiphenylmethane, 4,4'-diamino Diphenyl ether, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, , 2'-diaminodiphenyl ether, 2,3'-diaminodiphenyl ether, 4,4'-sulfonyldianiline, 3,3'-sulfonyldianiline, bis (4-aminophenyl) silane, bis (3-aminophenyl) silane Dimethyl-bis (4-aminophenyl) silane, dimethyl-bis (3-aminophenyl) silane, 4,4'-thiodianiline, 3,3'-thiodianiline, 4,4'-diaminodiphenylamine, 3,3'- Diaminodiphenylamine, 3,4'-diaminodiphenylamine, 2,2'-diaminodiphenylamine, 2,3'-diaminodiphenylamine, N-methyl (4,4'-diaminodiphenyl) amine, N-methyl (3,3'- Diaminodiphenyl) amine, N-methyl (3,4'-diaminodiphenyl) ) Amine, N-methyl (2,2′-diaminodiphenyl) amine, N-methyl (2,3′-diaminodiphenyl) amine, 4,4′-diaminobenzophenone, 3,3′-diaminobenzophenone, 3,4 '-Diaminobenzophenone, 1,4-diaminonaphthalene, 2,2'-diaminobenzophenone, 2,3'-diaminobenzophenone, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 1 , 8-diaminonaphthalene, 2,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 2,8-diaminonaphthalene, 1,2-bis (4-aminophenyl) ethane, 1,2 -Bis (3-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,3 Bis (3-aminophenyl) propane, 1,4-bis (4aminophenyl) butane, 1,4-bis (3-aminophenyl) butane, bis (3,5-diethyl-4-aminophenyl) methane, , 4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene 1,4-bis (4-aminobenzyl) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4 ′-[1,4-phenylenebis (methylene)] dianiline, 4,4′- [1,3-phenylenebis (methylene)] dianiline, 3,4 '-[1,4-phenylenebis (methylene)] dianiline, 3,4'-[1,3-phenylenebis (methylene) ] Dianiline, 3,3 ′-[1,4-phenylenebis (methylene)] dianiline, 3,3 ′-[1,3-phenylenebis (methylene)] dianiline, 1,4-phenylenebis [(4-amino Phenyl) methanone], 1,4-phenylenebis [(3-aminophenyl) methanone], 1,3-phenylenebis [(4-aminophenyl) methanone], 1,3-phenylenebis [(3-aminophenyl) Methanone], 1,4-phenylenebis (4-aminobenzoate), 1,4-phenylenebis (3-aminobenzoate), 1,3-phenylenebis (4-aminobenzoate), 1,3-phenylenebis (3 -Aminobenzoate), bis (4-aminophenyl) terephthalate, bis (3-aminophenyl) terephthalate, bis (4-amino) Phenyl) isophthalate, bis (3-aminophenyl) isophthalate, N, N ′-(1,4-phenylene) bis (4-aminobenzamide), N, N ′-(1,3-phenylene) bis (4 -Aminobenzamide), N, N '-(1,4-phenylene) bis (3-aminobenzamide), N, N'-(1,3-phenylene) bis (3-aminobenzamide), N, N'- Bis (4-aminophenyl) terephthalamide, N, N′-bis (3-aminophenyl) terephthalamide, N, N′-bis (4-aminophenyl) isophthalamide, N, N′-bis (3-amino Phenyl) isophthalamide, 9,10-bis (4-aminophenyl) anthracene, 4,4′-bis (4-aminophenoxy) diphenylsulfone, 2,2′-bis [4 (4-aminophenoxy) phenyl] propane, 2,2′-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2′-bis (4-aminophenyl) hexafluoropropane, 2,2 '-Bis (3-aminophenyl) hexafluoropropane, 2,2'-bis (3-amino-4-methylphenyl) hexafluoropropane, 2,2'-bis (4-aminophenyl) propane, 2,2 '-Bis (3-aminophenyl) propane, 2,2'-bis (3-amino-4-methylphenyl) propane, 1,3-bis (4-aminophenoxy) propane, 1,3-bis (3- Aminophenoxy) propane, 1,4-bis (4-aminophenoxy) butane, 1,4-bis (3-aminophenoxy) butane, 1,5-bis (4-a Nophenoxy) pentane, 1,5-bis (3-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,6-bis (3-aminophenoxy) hexane, 1,7- Bis (4-aminophenoxy) heptane, 1,7- (3-aminophenoxy) heptane, 1,8-bis (4-aminophenoxy) octane, 1,8-bis (3-aminophenoxy) octane, 1,9 -Bis (4-aminophenoxy) nonane, 1,9-bis (3-aminophenoxy) nonane, 1,10- (4-aminophenoxy) decane, 1,10- (3-aminophenoxy) decane, 1,11 -(4-aminophenoxy) undecane, 1,11- (3-aminophenoxy) undecane, 1,12- (4-aminophenoxy) dodecane, 1,12- (3- Aminophenoxy) dodecane, 4- (aminomethyl) aniline, 3- (aminomethyl) aniline, 3-((aminomethyl) methyl) aniline, 4- (2-aminoethyl) aniline or 3- (2-aminoethylaniline) ), Alicyclic diamines such as bis (4-aminocyclohexyl) methane or bis (4-amino-3-methylcyclohexyl) methane, 1,3-diaminopropane, 1,4-diaminobutane, , 5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane or 1, Also included are aliphatic diamines such as 12-diaminododecane.

The above-mentioned other diamine compounds can be used alone or in combination of two or more according to properties such as liquid crystal alignment properties, voltage holding ratio, and accumulated charge when a liquid crystal alignment film is formed.

The method for synthesizing the solvent-soluble polyimide contained in the liquid crystal aligning agent of the present invention is not particularly limited except that the diamine compound represented by the above formula (1) is part of the raw material. Usually, it is obtained by reacting a diamine component and a tetracarboxylic acid component. In general, first, at least one tetracarboxylic acid component selected from the group consisting of tetracarboxylic acids and derivatives thereof is reacted with a diamine component consisting of one or more diamine compounds to form a polyamic acid. obtain. In order to obtain a polyamic acid ester, a method of converting a carboxyl group of the polyamic acid into an ester is used. And a polyimide is obtained by imidating polyimide precursors, such as these polyamic acid or polyamic acid ester.

It is preferable to use a tetracarboxylic dianhydride represented by the following formula (3) as a tetracarboxylic acid component that is a raw material of the solvent-soluble polyimide.

(In Formula (3), Z ₁ is a tetravalent organic group having 4 to 13 carbon atoms containing a non-aromatic cyclic hydrocarbon group having 4 to 6 carbon atoms.)

In formula (3), specific examples of Z ₁ include tetravalent organic groups represented by the following formulas (3a) to (3j).

(In the formula (3a), Z ₂ to Z ₅ are a hydrogen atom, a methyl group, a chlorine atom or a benzene ring, which may be the same or different, and in the formula (3g), Z ₆ and Z ₇ is a hydrogen atom or a methyl group, which may be the same or different.

In formula (3), particularly preferred structure of Z ₁ is represented by formula (3a), formula (3c), formula (3d), formula (3e), formula (3f) or formula because of polymerization reactivity and ease of synthesis. (3g). Among these, the formula (3a), the formula (3e), the formula (3f), or the formula (3g) is preferable.

Moreover, the ratio of the tetracarboxylic dianhydride shown by said Formula (3) with respect to the tetracarboxylic-acid component whole quantity which is a raw material of solvent soluble polyimide is not specifically limited, For example, the tetracarboxylic-acid component which is a raw material is said Formula ( Only the tetracarboxylic dianhydride represented by 3) may be used. Of course, the tetracarboxylic acid component, which is a raw material for the solvent-soluble polyimide, is a tetracarboxylic acid or tetracarboxylic acid derivative other than the tetracarboxylic dianhydride represented by the above formula (3) as long as the effects of the present invention are not impaired. May be included. In that case, it is preferable that 1 mol% or more of the total amount of the tetracarboxylic acid component is a tetracarboxylic dianhydride represented by the above formula (3), more preferably 5 mol% or more, and still more preferably 10 mol%. That's it.

Other tetracarboxylic dianhydrides other than the tetracarboxylic dianhydride represented by the above formula (3) include pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6 -Naphthalene tetracarboxylic acid, 1,4,5,8-naphthalene tetracarboxylic acid, 2,3,6,7-anthracene tetracarboxylic acid, 1,2,5,6-anthracene tetracarboxylic acid, 3,3 ', 4,4′-biphenyltetracarboxylic acid, 2,3,3 ′, 4-biphenyltetracarboxylic acid, bis (3,4-dicarboxyphenyl) ether, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid Bis (3,4-dicarboxyphenyl) sulfone, bis (3,4-dicarboxyphenyl) methane, 2,2-bis (3,4-dicarboxyphenyl) propa 1,1,1,3,3,3-hexafluoro-2,2-bis (3,4-dicarboxyphenyl) propane, bis (3,4-dicarboxyphenyl) dimethylsilane, bis (3,4 -Dicarboxyphenyl) diphenylsilane, 2,3,4,5-pyridinetetracarboxylic acid, 2,6-bis (3,4-dicarboxyphenyl) pyridine, 3,3 ', 4,4'-diphenylsulfonetetra Carboxylic acid, 3,4,9,10-perylenetetracarboxylic acid or 1,3-diphenyl-1,2,3,4-cyclobutanetetracarboxylic acid.

The tetracarboxylic dianhydride represented by the above formula (3) and other tetracarboxylic acids and tetracarboxylic acid derivatives have desired properties such as liquid crystal alignment, voltage holding ratio, and accumulated charge when used as a liquid crystal alignment film. Depending on the situation, one kind or a mixture of two or more kinds may be used.

The reaction between the diamine component and the tetracarboxylic acid component is usually carried out in an organic solvent. The organic solvent used at that time is not particularly limited as long as the generated polyimide precursor such as polyamic acid dissolves. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, γ- Butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, Ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol Nobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl Ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol Methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane , N-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, pyruvic acid Ethyl, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-metho Shipuropion acid, 3-methoxy propionic acid propyl, 3-methoxy propionic acid butyl, and the like diglyme or 4-hydroxy-4-methyl-2-pentanone. These may be used alone or in combination. Furthermore, even if it is a solvent which does not dissolve a polyimide precursor, you may mix and use the said solvent in the range which the produced | generated polyimide precursor does not precipitate. Moreover, since the water | moisture content in an organic solvent inhibits a polymerization reaction, and also causes the produced polyimide precursor to hydrolyze, it is preferable to use what dehydrated and dried the organic solvent.

When the diamine component and the tetracarboxylic acid component are reacted in an organic solvent, the solution in which the diamine component is dispersed or dissolved in the organic solvent is stirred, and the tetracarboxylic acid component is dispersed or dissolved in the organic solvent as it is. And a method of adding a diamine component to a solution obtained by dispersing or dissolving a tetracarboxylic acid component in an organic solvent, a method of alternately adding a tetracarboxylic acid component and a diamine component, and the like. Any of these methods may be used. In addition, when reacting using a plurality of diamine components or tetracarboxylic acid components, they may be reacted in a premixed state, individually or sequentially, or further individually reacted low molecular weight substances. May be mixed and reacted. In this case, the polymerization temperature can be selected from -20 ° C to 150 ° C, but is preferably in the range of -5 ° C to 100 ° C. The reaction can be carried out at any concentration, but if the concentration is too low, it is difficult to obtain a high molecular weight polyimide precursor (and thus polyimide), and if the concentration is too high, the viscosity of the reaction solution becomes too high. Uniform stirring becomes difficult. Therefore, the concentration of the total amount of the diamine component and the tetracarboxylic acid component is preferably 1 to 50% by mass, more preferably 5 to 30% by mass in the reaction solution. The initial stage of the reaction is carried out at a high concentration, and then an organic solvent can be added.

In the polymerization reaction of a polyimide precursor such as polyamic acid, the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic acid component is preferably 0.8 to 1.2. Similar to a normal polycondensation reaction, the molecular weight of the polyimide precursor produced increases as the molar ratio approaches 1.0.

The polyimide precursor thus polymerized is, for example, a polymer having a repeating unit represented by the following formula [a].

(In the formula [a], R ₁₁ is a tetravalent organic group, R ₁₂ is a divalent organic group derived from the diamine component of the raw material, and A ₁₁ and A ₁₂ are a hydrogen atom or a carbon number. 1 to 8 alkyl groups, which may be the same or different, and j represents a positive integer.)

In the above formula [a], each of R ₁₁ and R ₁₂ may be one type and a polymer having the same repeating unit, or R ₁₁ and R ₁₂ may be a plurality of types and a polymer having a repeating unit having a different structure. But you can.

In the above formula [a], R ₁₁ is a group derived from a tetracarboxylic acid component represented by the following formula [c] or the like which is a raw material. The base R ₁₂ is derived from a diamine component represented by the following formula as a starting material [b] or the like, for example, a group derived from a diamine compound R ₁₂ is represented by the above formula (1), R ₁₂ is —C ₆ H ₄ —Y ¹ —R ¹ —NH—C (═X ¹ ) —NH—Y ¹ —C ₆ H ₄ —.

(In formula [b] and formula [c], R ₁₁ and R ₁₂ are the same as defined in formula [a].)

And, polyimide is obtained by dehydrating and ring-closing such a polyimide precursor.

Examples of the method for imidizing the polyimide precursor include thermal imidization in which the polyimide precursor solution is heated as it is or catalytic imidization in which a catalyst is added to the polyimide precursor solution.

When the polyimide precursor is thermally imidized in a solution, the temperature is 100 ° C. to 400 ° C., preferably 120 ° C. to 250 ° C., and it is preferable to carry out while removing water generated by the imidation reaction from the system.

The catalyst imidation of the polyimide precursor can be performed by adding a basic catalyst and an acid anhydride to the polyimide precursor solution and stirring at -20 to 250 ° C, preferably 0 to 180 ° C. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times of the amic acid group, and the amount of the acid anhydride is 1 to 50 mol times, preferably 3 to 30 mol of the amido acid group. Is double. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has a basicity appropriate for advancing the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Among them, use of acetic anhydride is preferable because purification after completion of the reaction is facilitated. The imidization rate by catalytic imidation can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

When the produced polymer (polyimide) is recovered from the polymer (polyimide) reaction solution, the reaction solution may be poured into a solvent and precipitated. Examples of the solvent used for precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and water. The polymer that has been introduced into the solvent and precipitated can be recovered by filtration, and then dried at normal temperature or under reduced pressure at room temperature or by heating. In addition, when the polymer collected by precipitation is redissolved in an organic solvent and reprecipitation and collection is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the solvent at this time include alcohols, ketones, and hydrocarbons, and it is preferable to use three or more kinds of solvents selected from these because purification efficiency is further increased.

The dehydration cyclization rate (imidation rate) of the amic acid group of the solvent-soluble polyimide contained in the liquid crystal aligning agent of the present invention does not necessarily need to be 100%, and may be arbitrarily selected in the range of 0% to 100% depending on the application and purpose. However, 50% to 90% is preferable, and 82% to 86% is more preferable.

The molecular weight of the solvent-soluble polyimide is determined by the GPC (Gel Permeation Chromatography) method in consideration of the strength of the resulting polymer film (liquid crystal alignment film), the workability when forming the polymer film, and the uniformity of the polymer film. The measured weight average molecular weight is preferably 5,000 to 1,000,000, and more preferably 10,000 to 150,000.

<Polyamic acid>
The polyamic acid (also called polyamic acid) contained in the liquid crystal aligning agent of the present invention is obtained by polymerizing at least one tetracarboxylic acid component selected from tetracarboxylic acid and derivatives thereof and a diamine component. It is.

Examples of the diamine compound contained in the diamine component of the raw material of polyamic acid include p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, and m-phenylene. Diamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 2,5-diaminophenol, 2,4-diaminophenol, 3,5-diaminophenol, 3, 5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy -4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-dia Nobiphenyl, 3,3′-dicarboxy-4,4′-diaminobiphenyl, 3,3′-difluoro-4,4′-biphenyl, 3,3′-trifluoromethyl-4,4′-diaminobiphenyl, 3,4′-diaminobiphenyl, 3,3′-diaminobiphenyl, 2,2′-diaminobiphenyl, 2,3′-diaminobiphenyl, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 3, 4'-diaminodiphenylmethane, 2,2'-diaminodiphenylmethane, 2,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,2 ' -Diaminodiphenyl ether, 2,3'-diaminodiphenyl ether, 4 4'-sulfonyldianiline, 3,3'-sulfonyldianiline, bis (4-aminophenyl) silane, bis (3-aminophenyl) silane, dimethyl-bis (4-aminophenyl) silane, dimethyl-bis (3 -Aminophenyl) silane, 4,4'-thiodianiline, 3,3'-thiodianiline, 4,4'-diaminodiphenylamine, 3,3'-diaminodiphenylamine, 3,4'-diaminodiphenylamine, 2,2'-diamino Diphenylamine, 2,3'-diaminodiphenylamine, N-methyl (4,4'-diaminodiphenyl) amine, N-methyl (3,3'-diaminodiphenyl) amine, N-methyl (3,4'-diaminodiphenyl) Amine, N-methyl (2,2′-diaminodiphenyl) amine, N-methyl (2,3 '-Diaminodiphenyl) amine, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 1,4-diaminonaphthalene, 2,2'-diaminobenzophenone, 2,3' -Diaminobenzophenone, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 1,8-diaminonaphthalene, 2,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7- Diaminonaphthalene, 2,8-diaminonaphthalene, 1,2-bis (4-aminophenyl) ethane, 1,2-bis (3-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1 , 3-bis (3-aminophenyl) propane, 1,4-bis (4aminophenyl) butane, , 4-bis (3-aminophenyl) butane, bis (3,5-diethyl-4-aminophenyl) methane, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) ) Benzene, 1,4-bis (4-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,4-bis (4-aminobenzyl) benzene, 1,3-bis (4- Aminophenoxy) benzene, 4,4 ′-[1,4-phenylenebis (methylene)] dianiline, 4,4 ′-[1,3-phenylenebis (methylene)] dianiline, 3,4 ′-[1,4 -Phenylenebis (methylene)] dianiline, 3,4 '-[1,3-phenylenebis (methylene)] dianiline, 3,3'-[1,4-phenylenebis (methylene)] dianiline, 3 3 ′-[1,3-phenylenebis (methylene)] dianiline, 1,4-phenylenebis [(4-aminophenyl) methanone], 1,4-phenylenebis [(3-aminophenyl) methanone], 1, 3-phenylenebis [(4-aminophenyl) methanone], 1,3-phenylenebis [(3-aminophenyl) methanone], 1,4-phenylenebis (4-aminobenzoate), 1,4-phenylenebis ( 3-aminobenzoate), 1,3-phenylenebis (4-aminobenzoate), 1,3-phenylenebis (3-aminobenzoate), bis (4-aminophenyl) terephthalate, bis (3-aminophenyl) terephthalate, Bis (4-aminophenyl) isophthalate, bis (3-aminophenyl) isophthalate, N, N′- (1,4-phenylene) bis (4-aminobenzamide), N, N ′-(1,3-phenylene) bis (4-aminobenzamide), N, N ′-(1,4-phenylene) bis (3 -Aminobenzamide), N, N ′-(1,3-phenylene) bis (3-aminobenzamide), N, N′-bis (4-aminophenyl) terephthalamide, N, N′-bis (3-amino) Phenyl) terephthalamide, N, N′-bis (4-aminophenyl) isophthalamide, N, N′-bis (3-aminophenyl) isophthalamide, 9,10-bis (4-aminophenyl) anthracene, 4, 4′-bis (4-aminophenoxy) diphenylsulfone, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, 2,2′-bis [4- (4-amino Enoxy) phenyl] hexafluoropropane, 2,2′-bis (4-aminophenyl) hexafluoropropane, 2,2′-bis (3-aminophenyl) hexafluoropropane, 2,2′-bis (3-amino) -4-methylphenyl) hexafluoropropane, 2,2'-bis (4-aminophenyl) propane, 2,2'-bis (3-aminophenyl) propane, 2,2'-bis (3-amino-4) -Methylphenyl) propane, 1,3-bis (4-aminophenoxy) propane, 1,3-bis (3-aminophenoxy) propane, 1,4-bis (4-aminophenoxy) butane, 1,4-bis (3-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,5-bis (3-aminophenoxy) pentane, 1,6 Bis (4-aminophenoxy) hexane, 1,6-bis (3-aminophenoxy) hexane, 1,7-bis (4-aminophenoxy) heptane, 1,7- (3-aminophenoxy) heptane, , 8-bis (4-aminophenoxy) octane, 1,8-bis (3-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,9-bis (3-aminophenoxy) nonane 1,10- (4-aminophenoxy) decane, 1,10- (3-aminophenoxy) decane, 1,11- (4-aminophenoxy) undecane, 1,11- (3-aminophenoxy) undecane, , 12- (4-aminophenoxy) dodecane, 1,12- (3-aminophenoxy) dodecane, 4- (aminomethyl) aniline, 3- (aminomethyl) Aromatic diamines such as aniline, 3-((aminomethyl) methyl) aniline, 4- (2-aminoethyl) aniline or 3- (2-aminoethylaniline), bis (4-aminocyclohexyl) methane or bis (4 -Amino-3-methylcyclohexyl) alicyclic diamines such as methane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diamino Aliphatic diamines such as heptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane or 1,12-diaminododecane, and 3,5-diamino-N- Heterocycle-containing diamines such as (pyridin-3-ylmethyl) benzamine are also included.

The above diamine compounds may be used alone or in combination of two or more depending on the properties such as liquid crystal orientation, voltage holding ratio, and accumulated charge when the liquid crystal alignment film is formed.

As a tetracarboxylic acid component that is a raw material of polyamic acid, it is preferable to use a tetracarboxylic dianhydride represented by the above formula (3). In the tetracarboxylic acid component which is a raw material of polyamic acid, in Formula (3), particularly preferred structure of Z ₁ is the above formula (3a), formula (3c), formula (3d) from the viewpoint of polymerization reactivity and ease of synthesis. ), Formula (3e), formula (3f), or formula (3g). Among these, the formula (3a), the formula (3e), the formula (3f), or the formula (3g) is preferable.

Moreover, the ratio of the tetracarboxylic dianhydride shown by the said Formula (3) with respect to the tetracarboxylic-acid component whole quantity which is a raw material of polyamic acid is not specifically limited, For example, the tetracarboxylic-acid component which is a raw material is said Formula (3). Only the tetracarboxylic dianhydride shown in FIG. Of course, the tetracarboxylic acid component, which is a raw material for the solvent-soluble polyimide, is a tetracarboxylic acid or tetracarboxylic acid derivative other than the tetracarboxylic dianhydride represented by the above formula (3) as long as the effects of the present invention are not impaired. May be included. In that case, it is preferable that 1 mol% or more of the total amount of the tetracarboxylic acid component is a tetracarboxylic dianhydride represented by the above formula (3), more preferably 5 mol% or more, and still more preferably 10 mol%. That's it.

The reaction between the diamine component and the tetracarboxylic acid component is usually carried out in an organic solvent. The organic solvent used in that case is not particularly limited as long as the generated polyamic acid is soluble. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, γ- Butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, Ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol Nobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl Ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol Methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane , N-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, pyruvic acid Ethyl, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-metho Shipuropion acid, 3-methoxy propionic acid propyl, 3-methoxy propionic acid butyl, and the like diglyme or 4-hydroxy-4-methyl-2-pentanone. These may be used alone or in combination. Furthermore, even if the solvent does not dissolve the polyamic acid, it may be used by mixing with the above solvent as long as the produced polyamic acid does not precipitate. Moreover, since water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the produced polyamic acid, it is preferable to use a dehydrated and dried organic solvent.

When the diamine component and the tetracarboxylic acid component are reacted in an organic solvent, the solution in which the diamine component is dispersed or dissolved in the organic solvent is stirred, and the tetracarboxylic acid component is dispersed or dissolved in the organic solvent as it is. And a method of adding a diamine component to a solution obtained by dispersing or dissolving a tetracarboxylic acid component in an organic solvent, a method of alternately adding a tetracarboxylic acid component and a diamine component, and the like. Any of these methods may be used. In addition, when reacting using a plurality of diamine components or tetracarboxylic acid components, they may be reacted in a premixed state, individually or sequentially, or further individually reacted low molecular weight substances. May be mixed and reacted. In this case, the polymerization temperature can be selected from -20 ° C to 150 ° C, but is preferably in the range of -5 ° C to 100 ° C. The reaction can be carried out at any concentration, but if the concentration is too low, it will be difficult to obtain a high molecular weight polyamic acid, and if the concentration is too high, the viscosity of the reaction solution will become too high and uniform stirring will be difficult. It becomes. Therefore, the concentration of the total amount of the diamine component and the tetracarboxylic acid component is preferably 1 to 50% by mass, more preferably 5 to 30% by mass in the reaction solution. The initial stage of the reaction is carried out at a high concentration, and then an organic solvent can be added.

In the polymerization reaction of polyamic acid, the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic acid component is preferably 0.8 to 1.2. Similar to the normal polycondensation reaction, the closer the molar ratio is to 1.0, the higher the molecular weight of the polyamic acid produced.

The polyamic acid polymerized in this way is, for example, a polymer having a repeating unit represented by the following formula [d].

(In the formula [d], R ²¹ is a tetravalent organic group, R ²² is a divalent organic group derived from the diamine component of the raw material, and k represents a positive integer.)

In the above formula [d], R ²¹ and R ²² may each be one type and a polymer having the same repeating unit, or R ²¹ and R ²² may be a plurality of types and a polymer having a repeating unit having a different structure. But you can.

In the above formula [d], R ²¹ is a group derived from a tetracarboxylic acid component represented by the following formula [f] or the like which is a raw material. In the formula [d], R ²² is a group derived from a diamine component represented by the following formula [e] or the like which is a raw material.

(In formula [f] and formula [e], R ²¹ and R ²² are the same as defined in formula [d].)

When the produced polymer (polyamic acid) is recovered from the reaction solution of the polymer (polyamic acid), the reaction solution may be poured into a solvent and precipitated. Examples of the solvent used for precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and water. The polymer that has been introduced into the solvent and precipitated can be recovered by filtration, and then dried at normal temperature or under reduced pressure at room temperature or by heating. In addition, when the polymer collected by precipitation is redissolved in an organic solvent and reprecipitation and collection is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the solvent at this time include alcohols, ketones, and hydrocarbons, and it is preferable to use three or more kinds of solvents selected from these because purification efficiency is further increased.

Further, the molecular weight of the polyamic acid is a weight average molecular weight measured by GPC (Gel Permeation Chromatography) method in consideration of the strength of the obtained polymer film, workability at the time of forming the polymer film, and uniformity of the polymer film. It is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000.

The mixing ratio of the solvent-soluble polyimide and the polyamic acid is not particularly limited. For example, the solvent-soluble polyimide / polyamic acid is 10/90 to 70/30 by mass ratio, and preferably the solvent-soluble polyimide / polyamic acid is mass ratio. Acid = 15/85 to 30/70, more preferably solvent-soluble polyimide / polyamic acid by mass ratio = 15/85 to 25/75.

<Solvent>
The solvent contained in the liquid crystal aligning agent of the present invention is not particularly limited as long as it can dissolve the above-mentioned solvent-soluble polyimide or polyamic acid, and N, N-dimethylformamide, N, N— Dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinylpyrrolidone, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, γ -Butyrolactone, 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme and 4-hydride Organic solvents, such as carboxymethyl-4-methyl-2-pentanone and the like. These may be used alone or in combination.

The solvent in the liquid crystal aligning agent of the present invention preferably has a solvent content of 70 to 99% by mass from the viewpoint of forming a uniform polymer film by coating. This content can be appropriately changed depending on the film thickness of the target liquid crystal alignment film.

Thus, by setting it as the liquid crystal aligning agent containing the solvent soluble polyimide which used the diamine compound represented by the said Formula (1) for at least one part of a raw material, a polyamic acid, and a solvent, it is mentioned in the Example mentioned later. As shown, whitening when applied to a substrate or the like is suppressed, and backlight resistance when the liquid crystal alignment film is formed is excellent. Therefore, for example, a liquid crystal alignment film having excellent uniformity and transparency can be produced even if the standing time after application to a substrate or the like is increased. Moreover, since this liquid crystal aligning film is excellent in backlight tolerance, the fall of the electrical property by backlight irradiation is suppressed and the liquid crystal display element which has the outstanding electrical property can be provided.

Whitening occurs when the solvent absorbs moisture in the air and the solubility of the polymer contained in the liquid crystal aligning agent decreases. In the case of a liquid crystal aligning agent containing a solvent-soluble polyimide and a polyamic acid, the solvent-soluble polyimide having a lower solubility in a solvent or water than the polyamic acid is precipitated. The solvent-soluble polyimide contained in the liquid crystal aligning agent of the present invention has a structure derived from the diamine compound represented by the above formula (1), and the structure of the diamine compound represented by the above formula (1) is polarized. It is bent greatly. Therefore, the solvent-soluble polyimide contained in the liquid crystal aligning agent of the present invention has higher solubility in a solvent and water than a polyimide not using the diamine compound represented by the above formula (1) as a raw material. Moreover, the solvent soluble polyimide which the liquid crystal aligning agent of this invention contains has NH of the urea structure derived from the diamine compound represented by the said Formula (1). And NH derived from the urea structure which this solvent soluble polyimide has couple | bonds with the carboxy group of polyamic acid by noncovalent bonds, such as a hydrogen bond, and the compatibility of solvent soluble polyimide and polyamic acid improves. Thus, the solubility of the solvent-soluble polyimide in the solvent and water is improved, and the compatibility between the solvent-soluble polyimide and the polyamic acid is improved, so that the stability of the solvent-soluble polyimide in the liquid crystal aligning agent is remarkable. Even if the solvent absorbs moisture in the air and the solubility of the solvent-soluble polyimide is somewhat reduced, the precipitation of the solvent-soluble polyimide is suppressed, and it is presumed that the whitening is suppressed. The whitening suppression effect exhibited in the liquid crystal aligning agent of the present invention is at a level that cannot be exhibited only by improving the solubility of the former solvent-soluble polyimide in a solvent or water. For example, instead of the solvent-soluble polyimide contained in the liquid crystal aligning agent of the present invention, the use of a polyimide having higher solubility in a solvent or water than the solvent-soluble polyimide contained in the liquid crystal aligning agent of the present invention improves whitening. I couldn't. Therefore, in the liquid crystal aligning agent of the present invention, not only the solubility of the solvent-soluble polyimide in the solvent and water but also the compatibility between the solvent-soluble polyimide and the polyamic acid was improved, and thus it can be said that whitening was remarkably suppressed. .

In addition, the present invention is excellent in backlight resistance as described above. Therefore, in the present invention, when the liquid crystal aligning agent is applied to the substrate, there are many solvent-soluble polyimides that generally have higher backlight resistance than polyamic acid at the interface between the coating film and the liquid crystal opposite to the substrate. It is considered to exist. For example, it is considered that a polyamic acid layer mainly composed of polyamic acid is formed on the substrate side, and a polyimide layer mainly composed of solvent-soluble polyimide is formed thereon.

Here, when the compatibility between the polyamic acid and the solvent-soluble polyimide is improved, it is considered that the two-layer separation between the polyamic acid layer and the polyimide layer hardly occurs when the liquid crystal aligning agent is applied to a substrate or the like. . That is, when the compatibility between the polyamic acid and the solvent-soluble polyimide is improved, the solvent-soluble polyimide and the polyamic acid are present in the form of islands at the interface with the liquid crystal, and the polyamic acid with weaker backlight resistance is also at the interface with the liquid crystal. Therefore, the backlight resistance is likely to be low. However, in the liquid crystal aligning agent of the present invention, the reason is unknown, but it is a liquid crystal aligning agent containing a solvent-soluble polyimide and a polyamic acid, which is suppressed in whitening and excellent in backlight resistance. .

In addition, the effect that such whitening is suppressed and the backlight resistance is excellent is that a solvent-soluble polyimide using a diamine compound represented by the above formula (1) as at least a part of a raw material and a polyamic acid. This effect is exhibited only when the liquid crystal aligning agent is contained. For example, as shown in a comparative example described later, instead of the diamine compound represented by the above formula (1) as a raw material for the solvent-soluble polyimide, the structure is similar to the formula (1) but different from the formula (1). When certain 1- (4-aminobenzyl) -3- (4-aminophenylethyl) urea is used, whitening of the present invention is suppressed and the effect of excellent backlight resistance cannot be obtained. Moreover, the diamine compound represented by Formula (1) needs to be used as a raw material for solvent-soluble polyimide, and even if it is used as a raw material for polyamic acid, the effects of the present invention cannot be exhibited.

<Other components of liquid crystal aligning agent>
In the liquid crystal aligning agent of the present invention, the polymer component may be only a solvent-soluble polyimide and a polyamic acid using the diamine compound represented by the above formula (1) as at least a part of the raw material. The other polymer may be mixed with the solvent-soluble polyimide and polyamic acid using the diamine compound represented by (2) as at least a part of the raw material. At that time, the content of other polymers other than the solvent-soluble polyimide and polyamic acid using the diamine compound represented by the above formula (1) as at least a part of the raw material is 0.5 to It is 15% by mass, preferably 1.0 to 10% by mass. As another polymer other than that, the polyimide obtained from the diamine component and tetracarboxylic acid component which do not contain the diamine compound represented by the said Formula (1) is mentioned. Furthermore, polymers other than polyamic acid and polyimide, specifically, polyamic acid ester, acrylic polymer, methacrylic polymer, polystyrene or polyamide are also included.

As long as the liquid crystal aligning agent of the present invention does not impair the effects of the present invention, an organic solvent (also called a poor solvent) that improves the uniformity and surface smoothness of the polymer film when the liquid crystal aligning agent is applied, or A compound may be contained. Furthermore, you may contain the compound etc. which improve the adhesiveness of a liquid crystal aligning film and a board | substrate.

Specific examples of poor solvents that improve film thickness uniformity and surface smoothness include isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol Thor, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl Ether, diethylene glycol, diethylene glycol monoa Tate, Diethylene glycol dimethyl ether, Dipropylene glycol monoacetate monomethyl ether, Dipropylene glycol monomethyl ether, Dipropylene glycol monoethyl ether, Dipropylene glycol monoacetate monoethyl ether, Dipropylene glycol monopropyl ether, Dipropylene glycol monoacetate monopropyl ether , 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexane Xene, propyl ether, dihexyl ether, n- Xanthone, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, 3-methoxypropionic acid Methyl, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2 Acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl ester or Examples thereof include organic solvents having a low surface tension such as isoamyl lactate.

These poor solvents may be used alone or in combination. When the above poor solvent is used, it is preferably 5 to 80% by mass, more preferably 20 to 60% by mass, based on the total organic solvent contained in the liquid crystal aligning agent.

Examples of compounds that improve film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. More specifically, for example, F-top EF301, EF303, EF352 (manufactured by Tochem Products), MegaFuck F171, F173, R-30 (manufactured by Dainippon Ink), Florard FC430, FC431 (manufactured by Sumitomo 3M), Asahi Guard Examples include AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass). The use ratio of these surfactants is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent. .

Examples of the compound for improving the adhesion between the liquid crystal alignment film and the substrate include a functional silane-containing compound and an epoxy group-containing compound. For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltriethoxysilane, Aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3- Ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N- Limethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxy Silane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, ethylene glycol diglycidyl Ether, polyethylene grease 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, 2,2- Dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ′, N ′,-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane or N, N, N ′, N ′,-tetraglycidyl-4,4′-diaminodiphenylmethane.

When using a compound to be adhered to these substrates, the amount is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent. Part. If the amount is less than 0.1 part by mass, the effect of improving the adhesion cannot be expected, and if it exceeds 30 parts by mass, the orientation of the liquid crystal may deteriorate.

In the liquid crystal aligning agent of the present invention, in addition to the above poor solvent and compound, as long as the effects of the present invention are not impaired, the purpose is to change the electrical properties such as the dielectric constant and conductivity of the liquid crystal aligning film. A dielectric or conductive material may be added.

<Liquid crystal alignment film / liquid crystal display element>
The liquid crystal aligning agent of this invention can be used as a liquid crystal aligning film by apply | coating and baking on a board | substrate and performing alignment processing by a rubbing process, light irradiation, etc. In the case of vertical alignment, etc., it can be used as a liquid crystal alignment film without alignment treatment. The substrate used at this time is not particularly limited as long as it is a highly transparent substrate. In addition to a glass substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate can also be used. From the viewpoint of simplification of the process, it is preferable to use a substrate on which an ITO electrode for driving a liquid crystal is formed. In the reflective liquid crystal display element, an opaque substrate such as a silicon wafer can be used if only one substrate is used, and a material that reflects light such as aluminum can be used as an electrode in this case.

The method for applying the liquid crystal aligning agent is not particularly limited, but industrially, a method performed by screen printing, offset printing, flexographic printing, an inkjet method, or the like is common. Other coating methods include a dipping method, a roll coater method, a slit coater method, a spinner method, and a spray method, and these may be used depending on the purpose. Since the liquid crystal aligning agent of the present invention suppresses whitening, a liquid crystal aligning film excellent in uniformity and transparency can be produced even if the standing time after application to a substrate or the like is increased.

After the liquid crystal aligning agent is applied on the substrate, the liquid crystal alignment is performed by evaporating the solvent at 50 to 300 ° C., preferably 80 to 250 ° C., by a heating means such as a hot plate, a thermal circulation oven or an IR (infrared) oven. A film (polymer film) can be formed. If the thickness of the liquid crystal alignment film after baking is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may be lowered. Is 10 to 100 nm. When the liquid crystal is horizontally aligned or tilted, the fired liquid crystal alignment film is treated by rubbing or irradiation with polarized ultraviolet rays.

The liquid crystal display element of the present invention is a liquid crystal display element obtained by obtaining a substrate with a liquid crystal alignment film from the liquid crystal aligning agent of the present invention by the method described above, and then producing a liquid crystal cell by a known method. For example, the two substrates disposed so as to face each other, the liquid crystal layer provided between the substrates, and the liquid crystal aligning agent of the present invention provided between the substrate and the liquid crystal layer. A liquid crystal display device comprising a liquid crystal cell having a liquid crystal alignment film. As such a liquid crystal display element of the present invention, a twisted nematic (TN) method, a vertical alignment (VA) method, a horizontal alignment (IPS) method, an OCB alignment (OCB). There are various types such as Optically Compensated Bend.

As a liquid crystal cell manufacturing method, a pair of substrates on which the liquid crystal alignment film is formed is prepared, spacers are dispersed on the liquid crystal alignment film of one substrate, and the liquid crystal alignment film surface is on the inner side. And a method of sealing the substrate by injecting liquid crystal under reduced pressure, or a method of sealing the substrate by bonding the substrate after dropping the liquid crystal on the liquid crystal alignment film surface on which the spacers are dispersed.

Examples of the liquid crystal include a positive liquid crystal having a positive dielectric anisotropy and a negative liquid crystal having a negative dielectric anisotropy. Specifically, for example, MLC-2003, MLC-6608, MLC-6609 manufactured by Merck & Co., Inc. Etc. are used.

As described above, since the liquid crystal display element produced using the liquid crystal aligning agent of the present invention has a liquid crystal alignment film having excellent backlight resistance, the liquid crystal display element has excellent reliability, large screen, and high definition. It can be suitably used for a liquid crystal television.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples.
The abbreviations used in this example are as follows.

(Tetracarboxylic dianhydride)
CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride TDA: 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride PMDA: pyromellitic acid 2 Anhydride (diamine)
p-PDA: p-phenylenediamine DDM: 4,4′-diaminodiphenylmethane BAPU: 1,3-bis (4-aminophenethyl) urea ABAPHU: 1- (4-aminobenzyl) -3- (4-aminophenylethyl) ) Urea Me-3ABA: 3-((aminomethyl) methyl) aniline 3AMPDA: 3,5-diamino-N- (pyridin-3-ylmethyl) benzamine DBA: 3,5-diaminobenzoic acid C16DAB: 4-hexadecyloxy -1,3-diaminobenzene C18DAB: 4-octadecyloxy-1,3-diaminobenzene (additive)
LS-2450: 3-aminopropyldiethoxymethylsilane (organic solvent)
NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve γ-BL: γ-butyrolactone

<Measurement of molecular weight>
The molecular weight of the polymer (polyimide, polyamic acid) obtained by the polymerization reaction is measured with a GPC (room temperature gel permeation chromatography) apparatus, and the number average molecular weight and the weight average molecular weight are converted into polyethylene glycol and polyethylene oxide equivalent values. Was calculated.
GPC device: manufactured by Shodex (GPC-101)
Column: manufactured by Shodex (series of KD803 and KD805)
Column temperature: 50 ° C
Eluent: N, N-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H ₂ O) 30 mmol / L, phosphoric acid / anhydrous crystals (o-phosphoric acid) 30 mmol / L, tetrahydrofuran) (THF) is 10 ml / L)
Flow rate: 1.0 ml / min Standard sample for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation and polyethylene glycol (manufactured by Polymer Laboratories) Molecular weight about 12,000, 4,000, 1,000).

Synthesis Example 1 Synthesis of BAPU: 1,3-bis (4-aminophenethyl) urea

At room temperature, 2- (4-nitrophenyl) ethylamine hydrochloride [A] (52.50 g, 259 mmol), bis (4-nitrophenyl) carbonate [B] (37.53 g) was placed in a nitrogen-substituted four-necked flask. 123 mmol) and THF (tetrahydrofuran) (1877 g) were added thereto, and triethylamine (74.90 g, 740 mmol) and 4-N, N-dimethylaminopyridine (3.01 g, 24.7 mmol) were added thereto. Stirring was performed. The reaction was monitored by HPLC (high performance liquid chromatography). After the reaction was completed, the reaction solution was added into pure water (9 L) and stirred for 30 minutes. Then, it filtered and wash | cleaned with the pure water (1L), and obtained the white solid crude substance. The obtained white solid was dispersed and washed with methanol (488 g) using an ultrasonic device, followed by filtration and drying to obtain a white solid dinitro compound [C] (amount 42.3 g, yield 96%). ).
¹ H-NMR (400 MHz, DMSO-d6, δ ppm): 8.11-8.08 (4H, m), 7.43-7.40 (4H, m), 5.89 (2H, t), 3.24-3.19 (4H, q), 2.76 ( 4H, t).

A mixture of compound [C] (42.32 g, 118 mmol), 5% palladium carbon (5% Pd / C) (4.23 g) and 1,4-dioxane (2031 g) was replaced with nitrogen and then with hydrogen. Then, the mixture was stirred at room temperature in the presence of hydrogen. The reaction was monitored by HPLC, and after completion of the reaction, the catalyst was filtered through celite. Thereafter, the solvent of the filtrate was distilled off under reduced pressure to obtain a white solid crude product. 2-Propanol (85 g) was added to the resulting crude product, dispersed and washed with an ultrasonic device, and then filtered and dried to obtain a white solid diamine compound BAPU (amount 31.9 g, yield). 91%).
¹ H-NMR (400 MHz, DMSO-d6, δ ppm): 6.85-6.82 (4H, m), 6.51-6.48 (4H, m), 5.78 (2H, t), 4.83 (4H, s), 3.14-3.09 4H, m), 2.50-2.45 (4H, m).

[Comparative Synthesis Example 1] ABAPHU: Synthesis of 1- (4-aminobenzyl) -3- (4-aminophenylethyl) urea

4-Nitrobenzylamine hydrochloride [D] (50.00 g, 265 mmol), pyridine (20.97 g, 265 mmol) and dichloromethane (750 g) were added to a nitrogen-substituted four-necked flask at room temperature, and the solution was cooled to 10 ° C. Cooled to: Thereto was added a solution of 4-nitrophenyl chloroformate [E] (53.43 g, 265 mmol) in dichloromethane (150 g), the reaction temperature was raised to 23 ° C. and the mixture was stirred for 1 hour, and then heated to reflux. After completion of the reaction, the reaction solution was cooled to room temperature, and dichloromethane (500 g) and an aqueous hydrochloric acid solution (1000 g) diluted to 10% by mass were added to perform filtration. The filtrate was stirred at room temperature and the precipitated solid was filtered. This solid was washed with methanol (200 g) and dried to obtain a white solid compound [F] (amount 33.26 g, yield 40%). On the other hand, a saturated aqueous sodium hydrogen carbonate solution (500 g) was added to the filtrate, and after washing, the organic layer was further washed with saturated brine (500 g) and dried over magnesium sulfate. Thereafter, the mixture was filtered and the solvent was distilled off to obtain a white crude product. This crude product was recrystallized from methanol (200 g) to obtain a white solid compound [F] (amount 16.6 g, yield 20%).
¹ H-NMR (400 MHz, CDCl ₃ , δ ppm): 8.28-8.24 (4H, m), 7.55-7.53 (2H, m), 7.37-7.34 (2H, m), 5.64 (1H, t), 4.59 (2H , d).

2- (4-Nitrophenyl) ethylamine hydrochloride [G] (30.29 g, 150 mmol), compound [F] (45.18 g, 142 mmol) and THF (2260 g) in a nitrogen-substituted four-necked flask at room temperature Was added thereto, and triethylamine (43.23 g, 427 mmol) and 4-N, N-dimethylaminopyridine (1.74 g, 14.2 mmol) were added thereto to carry out the reaction. The reaction was monitored by HPLC. After completion of the reaction, the reaction solution was added into pure water (10 L) and stirred for 30 minutes. Then, it filtered and wash | cleaned with the pure water (2L), and obtained the white solid crude substance. The obtained white solid was washed with 2-propanol (300 g), filtered and dried to obtain a white solid dinitro compound [H] (amount 43.9 g, yield 90%).
¹ H-NMR (400 MHz, DMSO-d6, δ ppm): 8.19-8.14 (4H, m), 7.52-7.44 (4H, m), 6.62 (1H, t), 6.12 (1H, t), 4.31 (2H, d), 3.33 (2H, m), 2.86 (2H, t).

A mixture of compound [H] (50.00 g, 145 mmol), 5% palladium carbon (5% Pd / C) (5.0 g) and 1,4-dioxane (1000 g) was replaced with nitrogen and then with hydrogen. The mixture was stirred again at room temperature in the presence of hydrogen. The reaction was monitored by HPLC, and after completion of the reaction, the catalyst was filtered through celite. Thereafter, the solvent of the filtrate was distilled off under reduced pressure to obtain a brown white solid crude product. 2-Propanol (330 g) was added to the crude product and dispersed and washed with an ultrasonic device, followed by filtration and drying to obtain a peach white solid diamine compound ABAPHU (yield 37.0 g, yield 90). %).
¹ H-NMR (400 MHz, DMSO-d6, δ ppm): 6.90-6.87 (2H, m), 6.84-6.82 (2H, m), 6.51-6.47 (4H, m), 6.08 (1H, t), 5.73 ( 1H, t), 4.9 (2H, s), 4.84 (2H, s), 3.99 (2H, d), 3.15-3.10 (2H, m), 2.51-2.46 (2H, m).

(Preparation of polymer solution 1) TDA / BAPU (10) p-PDA (80) C18DAB
As tetracarboxylic acid component, 10.50 g (0.035 mol) of TDA, 1.04 g (0.0035 mol) of BAPU, 3.03 g (0.028 mol) of p-PDA, and 1.31 g of C18DAB as diamine components (0.0035 mol) was reacted in 90.32 g of NMP at 50 ° C. for 24 hours to obtain a polyamic acid solution (PAA-1).

To 30.00 g of polyamic acid solution (PAA-1), 50.00 g of NMP, 10.78 g of acetic anhydride and 5.02 g of pyridine were added and stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 3 hours for reaction. It was. After completion of the reaction, the polymer was precipitated slowly into 335 g of methanol, stirred for 30 minutes, and then a solid was collected by filtration. The obtained solid was sufficiently washed with methanol and then vacuum-dried at 100 ° C. to obtain a polyimide powder. The number average molecular weight of this polyimide was 10,600, the weight average molecular weight was 26,200, and the imidation ratio was 82%.

Add 30.01 g of γ-BL to 2.61 g of the obtained polyimide powder, stir and dissolve at 50 ° C. for 24 hours, confirm that it is completely dissolved, 5.85 g of γ-BL, LS-2450 6.48 g of a 2% γ-BL solution was added and stirred at 50 ° C. for 24 minutes to obtain a polyimide solution (SPI-1) containing 6.0% by mass of polyimide and 94% by mass of γ-BL.

(Preparation of polymer solution 2) TDA / BAPU (20) p-PDA (70) C18DAB
As a tetracarboxylic acid component, 9.90 g (0.033 mol) of TDA, as a diamine component, 1.96 g (0.0066 mol) of BAPU, 2.50 g (0.023 mol) of p-PDA, and 1.25 g of C18DAB (0.0033 mol) was used and reacted at 88 ° C. in NMP 88.41 g for 24 hours to obtain a polyamic acid solution (PAA-2).

To 50.00 g of polyamic acid solution (PAA-2), 90.00 g of NMP, 18.11 g of acetic anhydride, and 8.42 g of pyridine were added and stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 3 hours for reaction. It was. After completion of the reaction, the polymer was slowly poured into 580 g of methanol to precipitate the polymer, stirred for 30 minutes, and then the solid was collected by filtration. The obtained solid was sufficiently washed with methanol and then vacuum-dried at 100 ° C. to obtain a polyimide powder. The number average molecular weight of this polyimide was 10,500, the weight average molecular weight was 25,200, and the imidation ratio was 84%.

69.23 g of γ-BL was added to 6.02 g of the obtained polyimide powder, and stirred and dissolved at 50 ° C. for 24 hours to confirm complete dissolution. 22.41 g of γ-BL, LS-2450 5.97 g of a 2% γ-BL solution was added and stirred at 50 ° C. for 24 minutes to obtain a polyimide solution (SPI-2) containing 6.0% by mass of polyimide and 94% by mass of γ-BL.

(Preparation of polymer solution 3) TDA / BAPU (30) p-PDA (60) C18DAB
As tetracarboxylic acid component, 9.31 g (0.031 mol) of TDA, 2.77 g (0.0093 mol) of BAPU, 2.01 g (0.019 mol) of p-PDA, and 1.17 g of C18DAB as diamine components (0.0031 mol) was used and reacted at 86 ° C. for 24 hours in 86.38 g of NMP to obtain a polyamic acid solution (PAA-3).

NMP (50.50 g), acetic anhydride (10.01 g) and pyridine (4.65 g) were added to 30.00 g of a polyamic acid solution (PAA-3), and the mixture was stirred at room temperature for 30 minutes and then stirred at 40 ° C. for 3 hours to cause a reaction. . After completion of the reaction, the polymer was slowly poured into 580 g of methanol to precipitate the polymer, stirred for 30 minutes, and then the solid was collected by filtration. The obtained solid was sufficiently washed with methanol and then vacuum-dried at 100 ° C. to obtain a polyimide powder. The number average molecular weight of this polyimide was 12,000, the weight average molecular weight was 28,500, and the imidation ratio was 82%.

30.59 g of γ-BL was added to 2.66 g of the obtained polyimide powder, stirred for 24 hours at 50 ° C. to dissolve, and confirmed to be completely dissolved. 6.55 g of γ-BL, LS-2450 6.83 g of a 2% γ-BL solution was added and stirred at 50 ° C. for 24 minutes to obtain a polyimide solution (SPI-3) containing 6.0% by mass of polyimide and 94% by mass of γ-BL.

(Preparation of polymer solution 4) TDA / BAPU (50) p-PDA (40) C18DAB
As tetracarboxylic acid component, 9.30 g (0.031 mol) of TDA, as diamine component, 4.63 g (0.016 mol) of BAPU, 1.35 g (0.012 mol) of p-PDA, and 1.17 g of C18DAB (0.0031 mol) was reacted in NMP 93.09 g at 50 ° C. for 24 hours to obtain a polyamic acid solution (PAA-4).

40.00 g of NMP, 8.66 g of acetic anhydride, and 4.03 g of pyridine were added to 30.00 g of polyamic acid solution (PAA-4), and the mixture was stirred at room temperature for 30 minutes and then stirred at 40 ° C. for 3 hours for reaction. . After completion of the reaction, the polymer was slowly poured into 300 g of methanol to precipitate a polymer, stirred for 30 minutes, and then a solid was collected by filtration. The obtained solid was sufficiently washed with methanol and then vacuum-dried at 100 ° C. to obtain a polyimide powder. The number average molecular weight of this polyimide was 11,200, the weight average molecular weight was 25,200, and the imidation ratio was 82%.

29.90 g of γ-BL was added to 2.60 g of the obtained polyimide powder, stirred and dissolved at 50 ° C. for 24 hours, and confirmed to be completely dissolved. 4.00 g of γ-BL, LS-2450 6.15 g of a 2% γ-BL solution was added and stirred at 50 ° C. for 24 minutes to obtain a polyimide solution (SPI-4) containing 6.0% by mass of polyimide and 94% by mass of γ-BL.

(Preparation of polymer solution 5) TDA / BAPU (90) C18DAB
As tetracarboxylic acid component, 7.50 g (0.025 mol) of TDA, 6.71 g (0.023 mol) of BAPU and 0.90 g (0.0025 mol) of C18DAB as diamine components, and 86.23 g of NMP, The mixture was reacted at 50 ° C. for 24 hours to obtain a polyamic acid solution (PAA-5).

51.00 g of NMP, 8.18 g of acetic anhydride and 3.80 g of pyridine were added to 30.00 g of polyamic acid solution (PAA-5), and the mixture was stirred at room temperature for 30 minutes and then stirred at 40 ° C. for 3 hours to cause a reaction. . After completion of the reaction, the polymer was slowly poured into 320 g of methanol to precipitate a polymer, stirred for 30 minutes, and then a solid was collected by filtration. The obtained solid was sufficiently washed with methanol and then vacuum-dried at 100 ° C. to obtain a polyimide powder. The number average molecular weight of this polyimide was 12,400, the weight average molecular weight was 27,400, and the imidation ratio was 82%.

30.71 g of γ-BL and 4.76 g of NMP were added to 2.67 g of the obtained polyimide powder, and the mixture was stirred and dissolved at 50 ° C. for 24 hours. After confirming that it was completely dissolved, 2% NMP of LS-2450 6.35 g of the solution was added and stirred at 50 ° C. for 24 minutes to obtain a polyimide solution (SPI-5) containing 6.0% by mass of polyimide, 69% by mass of γ-BL, and 25% by mass of NMP.

(Preparation of polymer solution 6) TDA / p-PDA (90) C16DAB
As the tetracarboxylic acid component, 7.51 g (0.025 mol) of TDA, 2.43 g (0.023 mol) of p-PDA and 0.87 g (0.0025 mol) of C16DAB were used as the diamine component, and NMP 61.26 g The mixture was reacted at 50 ° C. for 24 hours to obtain a polyamic acid solution (PAA-6).

30.67 g of NMP, 7.18 g of acetic anhydride and 3.33 g of pyridine were added to 20.00 g of the polyamic acid solution (PAA-6), and the mixture was stirred at room temperature for 30 minutes and then stirred at 40 ° C. for 3 hours to react. . After completion of the reaction, the polymer was slowly poured into 214 g of methanol to precipitate a polymer, stirred for 30 minutes, and then a solid was collected by filtration. The obtained solid was sufficiently washed with methanol and then vacuum-dried at 100 ° C. to obtain a polyimide powder. The number average molecular weight of this polyimide was 12,400, the weight average molecular weight was 27,400, and the imidation ratio was 88%.

29.90 g of γ-BL was added to 2.60 g of the obtained polyimide powder, stirred and dissolved at 50 ° C. for 24 hours, and confirmed to be completely dissolved. 4.00 g of γ-BL, LS-2450 6.15 g of a 2% γ-BL solution was added and stirred at 50 ° C. for 24 minutes to obtain a polyimide solution (SPI-6) containing 6.0% by mass of polyimide and 94% by mass of γ-BL.

(Preparation of polymer solution 7) CBDA (50) PMDA / DDM
As the tetracarboxylic acid component, 9.81 g (0.050 mol) of CBDA, 10.25 g (0.047 mol) of PMDA, and 19.83 g (0.0060 mol) of DDM as the diamine component were used. 00 g and NMP 113.00 g were reacted at room temperature for 3 hours to obtain a polyamic acid solution.

198.97 g of the resulting polyamic acid solution was diluted with 204.23 g of γ-BL, 14.63 g of NMP, and 73.74 g of BCS, and the solid content was 6 mass%, γ-BL was 59 mass%, and NMP was A polyamic acid solution (PAA-7) having 20% by mass and 15% by mass BCS was obtained. This polyamic acid had a number average molecular weight of 20,900 and a weight average molecular weight of 57,900.

(Preparation of polymer solution 8) CBDA / p-PDA (80) DDM
As a tetracarboxylic acid component, 3.01 g (0.015 mol) of CBDA and 1.56 g (0.014 mol) of p-PDA as a diamine component were used at room temperature in 15.18 g of γ-BL and 25.31 g of NMP. Then, 0.35 g (0.0018 mol) of the tetracarboxylic acid component CBDA, 0.72 g (0.036 mol) of the diamine component DDM, and 10.12 g of γ-BL were added at room temperature for 3 hours. The reaction was performed for a time to obtain a polyamic acid solution.

The resulting polyamic acid solution (47.37 g) was diluted with 52.28 g of γ-BL and 17.59 g of BCS, and the solid content was 4 mass%, γ-BL was 63 mass%, NMP was 18 mass%, and BCS was 15 mass%. A mass% polyamic acid solution (PAA-8) was obtained. This polyamic acid had a number average molecular weight of 19,800 and a weight average molecular weight of 59,200.

(Preparation of polymer solution 9) CBDA / p-PDA (60) DDM
As a tetracarboxylic acid component, 2.04 g (0.010 mol) of CBDA and 1.04 g (0.0096 mol) of p-PDA as a diamine component were used at room temperature in 23.80 g of γ-BL and 14.28 g of NMP. Then, 0.94 g (0.0048 mol) of the tetracarboxylic acid component CBDA, 1.26 g (0.064 mol) of the diamine component DDM, and 9.52 g of γ-BL were added, and the mixture was added at room temperature for 3 hours. The reaction was performed for a time to obtain a polyamic acid solution.

46.38 g of the obtained polyamic acid solution was diluted with 20.64 g of γ-BL and 11.83 g of BCS, the solid content was 6 mass%, γ-BL was 53 mass%, NMP was 26 mass%, BCS. Was 15% by mass of polyamic acid solution (PAA-9). This polyamic acid had a number average molecular weight of 10,300 and a weight average molecular weight of 33,100.

(Preparation of polymer solution 10) CBDA / 3AMPDA (30) p-PDA
As the tetracarboxylic acid component, 2.86 g (0.014 mol) of CBDA, 1.09 g (0.0045 mol) of 3AMPDA and 1.13 g (0.011 mol) of p-PDA as diamine components, 27.43 g of γ-BL The reaction was carried out in 18.35 g of NMP at room temperature for 3 hours to obtain a polyamic acid solution.

The resulting polyamic acid solution (43.49 g) was diluted with 21.82 g of γ-BL and 11.52 g of BCS, the solid content was 6 mass%, γ-BL was 59 mass%, NMP was 20 mass%, and BCS. Was 15% by mass of polyamic acid solution (PAA-10). This polyamic acid had a number average molecular weight of 11,500 and a weight average molecular weight of 24,000.

(Preparation of polymer solution 11) CBDA / p-PDA (55) DBA (30) Me-3ABA
As the tetracarboxylic acid component, 8.29 g (0.042 mol) of CBDA, 3.65 g (0.034 mol) of p-PDA, 0.68 g (0.0045 mol) of DBA, and 0 of Me-3ABA as the diamine component. .92 g (0.0068 mol) was reacted in 38.39 g of γ-BL and 38.39 g of NM for 3 hours at room temperature to obtain a polyamic acid solution.

80.90 g of the obtained polyamic acid solution was diluted with 84.95 g of γ-BL, 6.07 g of NMP, and 30.33 g of BCS, and the solid content was 6% by mass, γ-BL was 59% by mass, and NMP was 20%. A polyamic acid solution (PAA-11) having a mass% of BCS of 15% by mass was obtained. This polyamic acid had a number average molecular weight of 7,300 and a weight average molecular weight of 15,000.

(Preparation of polymer solution 12) TDA / p-PDA (90) C18DAB
As the tetracarboxylic acid component, 9.00 g (0.030 mol) of TDA, 2.92 g (0.027 mol) of p-PDA as the diamine component, 1.13 g (0.0030 mol) of C18DAB were used, and 73.40 g of NMP was used. The mixture was reacted at 50 ° C. for 24 hours to obtain a polyamic acid solution (PAA-12).

30.67 g of NMP, 7.16 g of acetic anhydride, and 3.32 g of pyridine were added to 20.00 g of the polyamic acid solution (PAA-12), and the mixture was stirred at room temperature for 30 minutes and then stirred at 40 ° C. for 3 hours to react. It was. After completion of the reaction, the polymer was slowly poured into 214 g of methanol to precipitate a polymer, stirred for 30 minutes, and then a solid was collected by filtration. The obtained solid was sufficiently washed with methanol and then vacuum dried at 100 ° C. to obtain a polyimide powder. The number average molecular weight of this polyimide was 11,280, the weight average molecular weight was 29,100, and the imidation ratio was 85%.

29.00 g of γ-BL was added to 2.60 g of the obtained polyimide powder, stirred and dissolved at 50 ° C. for 24 hours, and confirmed to be completely dissolved. 4.00 g of γ-BL, LS-2450 6.15 g of a 2% γ-BL solution was added and stirred at 50 ° C. for 24 minutes to obtain a polyimide solution (SPI-7) containing 6.0% by mass of polyimide and 94% by mass of γ-BL.

(Production of polymer solution 13)
TDA / ABAPHU (20) p-PDA (70) C18DAB
As a tetracarboxylic acid component, 5.10 g (0.017 mol) of TDA, 0.96 g (0.0034 mol) of ABAPHU, 1.29 g (0.012 mol) of p-PDA, and 0.64 g of C18DAB as a diamine component (0.0017 mol) was used and reacted at 45 ° C. for 24 hours in 45.47 g of NMP to obtain a polyamic acid solution (PAA-13).

To 44.71 g of polyamic acid solution (PAA-13), 70.79 g of NMP, 15.03 g of acetic anhydride and 6.99 g of pyridine were added and stirred at room temperature for 30 minutes and then stirred at 40 ° C. for 3 hours for reaction. It was. After completion of the reaction, the polymer was slowly poured into 481 g of methanol, and the polymer was stirred. After stirring for 30 minutes, the solid was recovered by filtration. The obtained solid was sufficiently washed with methanol and then vacuum dried at 100 ° C. to obtain a polyimide powder. The number average molecular weight of this polyimide was 7,400, the weight average molecular weight was 17,100, and the imidation ratio was 82%.

Add 36.92 g of γ-BL to 3.21 g of polyimide powder, stir and dissolve at 50 ° C. for 24 hours, and confirm that it is completely dissolved. 7.75 g of γ-BL, 9.86 g of NMP, Add 8.08 g of a 2% γ-BL solution of LS-2450 and stir at 50 ° C. for 24 minutes to obtain a polyimide solution containing 5.0% by weight of polyimide, 80% by weight of γ-BL, and 15% by weight of NMP. (SPI-8) was obtained.

(Example 1) Production of polymer solution 1 / Production of polymer solution 7 = 20/80
The polyimide solution (SPI-1) obtained in Preparation 1 of the polymer solution and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution were mixed so that the mass ratio was 20:80, And stirred for 1 hour to obtain a liquid crystal aligning agent.

(Example 2) Production of polymer solution 2 / Production of polymer solution 7 = 20/80
Mix the polyimide solution (SPI-2) obtained in Polymer Solution Preparation 2 and the polyamic acid solution (PAA-7) obtained in Polymer Solution Preparation 7 so that the mass ratio is 20:80, and And stirred for 1 hour to obtain a liquid crystal aligning agent.

(Example 3) Production of polymer solution 3 / Production of polymer solution 7 = 20/80
Mix the polyimide solution (SPI-3) obtained in Preparation 3 of the polymer solution and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution so that the mass ratio is 20:80, and And stirred for 1 hour to obtain a liquid crystal aligning agent.

(Example 4) Production of polymer solution 4 / Production of polymer solution 7 = 20/80
Mix the polyimide solution (SPI-4) obtained in Polymer Solution Preparation 4 and the polyamic acid solution (PAA-7) obtained in Polymer Solution Preparation 7 so that the mass ratio is 20:80, and And stirred for 1 hour to obtain a liquid crystal aligning agent.

(Example 5) Production of polymer solution 5 / Production of polymer solution 7 = 20/80
Mix the polyimide solution (SPI-5) obtained in Preparation 5 of the polymer solution and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution so that the mass ratio is 20:80, and And stirred for 1 hour to obtain a liquid crystal aligning agent.

Example 6 Production of Polymer Solution 2 / Production of Polymer Solution 7 = 30/70
The polyimide solution (SPI-2) obtained in Preparation 2 of the polymer solution and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution were mixed at a mass ratio of 30:70, And stirred for 1 hour to obtain a liquid crystal aligning agent.

Example 7 Production of Polymer Solution 2 / Production of Polymer Solution 7 = 40/60
Mix the polyimide solution (SPI-2) obtained in Polymer Solution Preparation 2 and the polyamic acid solution (PAA-7) obtained in Polymer Solution Preparation 7 so that the mass ratio is 40:60, and And stirred for 1 hour to obtain a liquid crystal aligning agent.

(Example 8) Production of polymer solution 2 / Production of polymer solution 7 = 50/50
Mix the polyimide solution (SPI-2) obtained in Preparation 2 of the polymer solution and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution so that the mass ratio is 50:50. And stirred for 1 hour to obtain a liquid crystal aligning agent.

Example 9 Production of Polymer Solution 2 / Production of Polymer Solution 7 = 70/30
The polyimide solution (SPI-2) obtained in Preparation 2 of the polymer solution and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution were mixed so that the mass ratio was 70:30, And stirred for 1 hour to obtain a liquid crystal aligning agent.

(Example 10) Production of polymer solution 2 / Production of polymer solution 8 = 20/80
Mix the polyimide solution (SPI-2) obtained in Preparation 2 of the polymer solution and the polyamic acid solution (PAA-8) obtained in Preparation 8 of the polymer solution so that the mass ratio is 20:80, and And stirred for 1 hour to obtain a liquid crystal aligning agent.

(Example 11) Production of polymer solution 2 / Production of polymer solution 9 = 20/80
Mix the polyimide solution (SPI-2) obtained in Preparation 2 of the polymer solution and the polyamic acid solution (PAA-9) obtained in Preparation 9 of the polymer solution so that the mass ratio is 20:80, and And stirred for 1 hour to obtain a liquid crystal aligning agent.

(Example 12) Production of polymer solution 2 / Production of polymer solution 10 = 20/80
Mix the polyimide solution (SPI-2) obtained in Preparation 2 of the polymer solution and the polyamic acid solution (PAA-10) obtained in Preparation 10 of the polymer solution so that the mass ratio is 20:80, and And stirred for 1 hour to obtain a liquid crystal aligning agent.

(Example 13) Production of polymer solution 2 / Production of polymer solution 11 = 20/80
The polyimide solution (SPI-2) obtained in Polymer Solution Preparation 2 and the polyamic acid solution (PAA-11) obtained in Polymer Solution Preparation 11 were mixed so that the mass ratio was 20:80, And stirred for 1 hour to obtain a liquid crystal aligning agent.

Comparative Example 1 Production of Polymer Solution 12 / Production of Polymer Solution 7 = 20/80
The polyimide solution (SPI-7) obtained in Preparation 12 of the polymer solution and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution were mixed so that the mass ratio was 20:80, The liquid crystal aligning agent was obtained by stirring at room temperature for 1 hour.

Comparative Example 2 Production of Polymer Solution 13 / Production of Polymer Solution 7 = 20/80
The polyimide solution (SPI-8) obtained in Preparation 13 of polymer solution and the polyamic acid solution (PAA-7) obtained in Preparation 7 of polymer solution were mixed so that the mass ratio was 20:80, The liquid crystal aligning agent was obtained by stirring at room temperature for 1 hour.

<Production of liquid crystal cell>
With respect to the liquid crystal aligning agents prepared in Examples 1 to 13 and the liquid crystal aligning agents prepared in Comparative Examples 1 and 2, liquid crystal cells were produced as follows.

A liquid crystal aligning agent is spin-coated on a glass substrate with a transparent electrode, dried on an 80 ° C. hot plate for 70 seconds, and then baked on a 210 ° C. hot plate for 10 minutes to form a coating film having a thickness of 100 nm. It was. This coating surface was rubbed with a rubbing apparatus having a roll diameter of 120 mm using a rayon cloth under the conditions of a roll rotation speed of 1000 rpm, a roll traveling speed of 50 mm / sec, and an indentation amount of 0.3 mm to obtain a substrate with a liquid crystal alignment film. Prepare two substrates with a liquid crystal alignment film, spray a 6μm spacer on the surface of one liquid crystal alignment film, print a sealant on it, and face the other substrate with the liquid crystal alignment film surface After laminating so that the rubbing direction was perpendicular, the sealing agent was cured to produce an empty cell. Liquid crystal MLC-2003 (manufactured by Merck Japan) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain a twisted nematic liquid crystal cell.

The characteristics of each produced liquid crystal cell and liquid crystal aligning agent were evaluated by the methods described below. The compositions of the liquid crystal aligning agents in Examples 1 to 13 and Comparative Examples 1 and 2 are shown in Table 1-1 and Table 1-2.

<Whitening evaluation>
One drop of each of the liquid crystal aligning agents prepared in Examples 1 to 13 and Comparative Examples 1 and 2 was dropped on a 10 cm Cr substrate until the liquid crystal aligning agent was whitened under conditions of a temperature of 23 ° C. and a humidity of 65%. Time was measured. The results are shown in Table 2.

<Evaluation of Backlight Resistance by Measuring Voltage Holding Ratio (VHR)>
For each of the produced twisted nematic liquid crystal cells, the voltage holding ratio (VHR) in an initial state where no backlight was irradiated was measured. The voltage holding ratio was measured by applying a voltage of 4 V for 60 μs at a temperature of 90 ° C., measuring the voltage after 166.7 ms, and calculating how much the voltage could be held as the voltage holding ratio. The voltage holding ratio was measured using a VHR-1 voltage holding ratio measuring device manufactured by Toyo Technica.

Thereafter, each twisted nematic liquid crystal cell was allowed to stand on the backlight module for 40 inch type liquid crystal TV for 240 hours, and the voltage holding ratio was measured by the same method as that for measuring the voltage holding ratio. Voltage holding ratio before irradiation of the backlight (indicated as “before BL” in Table 2) and voltage holding ratio after irradiation of the backlight for 240 hours (indicated as “after BL” in Table 2) The measurement results are shown in Table 2.

As a result, as shown in Table 2, in Examples 1 to 13 in which liquid crystal aligning agents containing polyimide and polyamic acid using the diamine compound represented by the above formula (1) as raw materials were used, Comparative Examples 1 to Compared to 2, the time required for whitening was remarkably long, and whitening was suppressed, and the decrease in VHR before and after the backlight irradiation was very small and the backlight resistance was excellent.

Claims

The liquid crystal aligning agent characterized by including the solvent soluble polyimide which used the diamine compound represented by following formula (1) for at least one part of a raw material, a polyamic acid, and a solvent.

(In the formula (1), X 1 is an oxygen atom or a sulfur atom, and Y 1 is a single bond, —O—, —S— or —COO— * (where a bond marked with “*” is R 1 And R 1 is an alkylene group having 1 to 3 carbon atoms.)
The liquid crystal aligning agent according to claim 1, wherein the diamine compound represented by the formula (1) is 10 to 90 mol% in the diamine component of the raw material of the solvent-soluble polyimide.
X 1 in the formula (1) is, the liquid crystal alignment agent according to claim 1 or 2, characterized in that an oxygen atom.
The liquid crystal aligning agent according to any one of claims 1 to 3, wherein the solvent-soluble polyimide uses a diamine compound represented by the following formula (2) as a part of a raw material.

(In Formula (2), R 2 is a single bond, —O— or a divalent organic group, X 2 , X 3 and X 4 are each independently a divalent benzene ring or a cyclohexane ring; , Q, and r are each independently an integer of 0 or 1, and R 3 is a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or a monovalent organic group having 12 to 25 carbon atoms having a steroid skeleton. .)
A liquid crystal alignment film obtained by using the liquid crystal aligning agent according to any one of claims 1 to 4.
A liquid crystal display element comprising the liquid crystal alignment film according to claim 5.