KR20140141689A - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

(식 (1) 중 X¹ 은 산소 원자 또는 황 원자이고, Y¹ 은 단결합, -O-, -S- 또는 -COO-* (단, 「*」를 붙인 결합손이 R¹ 과 결합한다) 이고, R¹ 은 탄소수 1 ∼ 3 의 알킬렌기이다)Soluble polyimide in which at least a part of the starting material is a diamine compound represented by the following formula (1), a polyamic acid, and a liquid crystal aligning agent containing a solvent.

X ¹ (wherein 1 is an oxygen atom or a sulfur atom, Y ¹ is bonded with a single bond, -O-, -S- or -COO- * (However, the coupling hand is attached to R ¹ '*' ) And R < ¹ > is an alkylene group having 1 to 3 carbon atoms)

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal alignment film, a liquid crystal alignment film, a liquid crystal alignment film,

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

BACKGROUND ART [0002] Liquid crystal display elements used in liquid crystal televisions, liquid crystal displays and the like are widely used as display devices realizing thinness and light weight. Called polyimide-based liquid crystal alignment film in which a liquid crystal aligning agent mainly composed of a polyimide precursor such as polyamic acid (also referred to as polyamic acid) or a soluble polyimide solution is applied to a glass substrate or the like and fired as a liquid crystal alignment film for orienting liquid crystal .

From the demands such as suppression of lowering of the contrast of the liquid crystal display element and reduction of the afterimage phenomenon accompanied by further enlargement and finer definition of the liquid crystal display element, the liquid crystal alignment film has excellent liquid crystal alignability and the alignment angle of liquid crystal molecules Tilt angle and pretilt angle), it is possible to provide a high voltage holding ratio, suppression of residual image caused by AC driving, a small residual charge when a direct current voltage is applied, a rapid relaxation of the accumulated residual charge due to a direct current voltage The same electrical characteristics have become increasingly important, and various studies have been made to improve these characteristics.

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

Japanese Patent Application Laid-Open No. 8-220541

However, such a liquid crystal aligning agent has a problem that when it is coated on a substrate or the like, it tends to be whitened by moisture absorption. The liquid crystal alignment film formed using such a liquid crystal aligning agent also has a problem that its electrical characteristics are easily deteriorated by irradiation of the backlight of the liquid crystal display element.

The object of the present invention is to provide a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element which are capable of suppressing whitening and having excellent backlight resistance.

As a result of intensive studies, the present inventors have found that a soluble polyimide having a specific structure of a diamine compound as a raw material and a liquid crystal aligning agent containing a polyamic acid are very effective for achieving the above object. It came.

That is, the present invention has the following points.

1. A liquid crystal aligning agent characterized by containing a solvent-soluble polyimide, a polyamic acid and a solvent, wherein at least a part of the starting material is a diamine compound represented by the following formula (1).

[Chemical Formula 1]

X ¹ (wherein 1 is an oxygen atom or a sulfur atom, Y ¹ is bonded with a single bond, -O-, -S- or -COO- * (However, the coupling hand is attached to R ¹ '*' ) And R < ¹ > is an alkylene group having 1 to 3 carbon atoms)

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

3. The liquid crystal aligning agent according to 1 or 2, wherein X ¹ in the formula (1) is an oxygen atom.

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

(2)

(2) wherein 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 cyclohexane ring, and p, q, And R ³ is a monovalent organic group having 12 to 25 carbon atoms and having a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or 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.

6. A liquid crystal display element having the liquid crystal alignment film according to Claim 5.

The liquid crystal aligning agent of the present invention is capable of suppressing whitening and having excellent backlight resistance. Therefore, a liquid crystal alignment film excellent in uniformity and transparency can be produced even if the time of leaving after application, for example, to a substrate is lengthened. Further, since this liquid crystal alignment film is excellent in backlight resistance, it is possible to provide a liquid crystal display device having excellent electrical characteristics by suppressing deterioration of electrical characteristics such as voltage holding ratio (VHR) by irradiation of a backlight.

Hereinafter, the present invention will be described in detail.

The liquid crystal aligning agent of the present invention contains a solvent-soluble polyimide, a polyamic acid, and a solvent in which at least a part of the starting material is used as the diamine compound represented by the formula (1). The liquid crystal aligning agent is a solution for preparing a liquid crystal alignment film, and the liquid crystal alignment film is a film for aligning the liquid crystal in a predetermined direction. Each component contained in the liquid crystal aligning agent of the present invention will be described in detail below.

Solvent-soluble polyimide using the diamine compound represented by the above formula (1) in at least part of the raw material>

The solvent-soluble polyimide is a polyimide which is dissolved in a solvent contained in a liquid crystal aligning agent, and at least one tetracarboxylic acid component selected from a tetracarboxylic acid and a derivative thereof, and a polyamic acid obtained by polymerizing a diamine component And polyimide precursors such as polyamic acid esters. The polyimide contained in the liquid crystal aligning agent of the present invention is a polymer synthesized by using the diamine compound represented by the formula (1) as a diamine component serving as a raw material.

As described above, X ¹ in the formula (1) is preferably an oxygen atom or a sulfur atom, and is preferably an oxygen atom. Y ¹ is preferably a single bond, -O-, -S- or -COO- * (provided that the bonding hand to which "*" is bonded to R ¹ ) is a single bond. R ¹ is an alkylene group having 1 to 3 carbon atoms, and is preferably an alkylene group having 2 carbon atoms. Further, X ^1, a preferred combination of Y ¹ and R ¹ is an alkylene group of X ¹ is an oxygen atom, Y ¹ is a single bond, R ¹ is C2. Further, as shown in the formula (1), the diamine compound represented by the formula (1) has two -Y ¹ -R ¹ - groups symmetrical with respect to the urea structure as a center.

The bonding position of two amino groups (-NH ₂ ) in the above formula (1) is not limited. Specifically, the number of the 2, 3 position, 2, 4-position, 2, 5-position, 2, 6-position, the 3 and 4 positions or the 3 and 5 position on the benzene ring for Y ¹ each have. Among them, from the viewpoint of reactivity at the time of synthesizing the polymer, positions 2 and 4, positions 2 and 5, and positions 3 and 5 are preferable. When the ease of synthesis of the diamine compound is also considered, positions 2 and 4 or positions 2 and 5 are more preferable.

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.

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

The method of synthesizing the diamine compound represented by the above formula (1) is not particularly limited, but can be synthesized by, for example, 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 into an amino group. R ¹ , Y ¹ and X ¹ in the formula (1A) are the same as those in the formula (1). There is no particular limitation on the method for reducing the dinitro compound. For example, there is no particular limitation on the method for reducing the dinitro compound by using palladium-carbon, platinum oxide, Raney nickel, iron, tin chloride, platinum black, rhodium- 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 toluene, tetrahydrofuran, dioxane or alcohol.

(3)

The method for synthesizing the dinitro compound represented by the formula (1A) is not particularly limited, and any method can be used. For example, the following method (I) can be mentioned.

[Chemical Formula 4]

In the scheme (I), the dinitro compound represented by the formula (1A) is a compound in which a nitrobenzene compound (?) And a (thio) carbonyl compound (generic name of a carbonyl compound and a thiocarbonyl compound) In a solvent in the presence of an alkali.

In the nitrobenzene compound (α), R ¹ and Y ¹ is an amino group represented by the same, and NH ₂ in equation (1) may form a salt such as hydrochloride (NH ₂ · HCl). For example, nitrobenzylamine or its hydrochloride, 2- (nitrophenyl) ethylamine or its hydrochloride, 3- (nitrophenyl) propylamine or its hydrochloride and the like can be mentioned. The substitution position of the nitro group on the benzene ring is suitably selected from the substitution position where the intended diamine compound is obtained. The compounds shown here are, for example, not particularly limited.

(Thio) carbonyl compound (X), X ¹ is the same as in formula (1), and Z is an organic group having 1 to 2 substituents. (Thio) carbonyl compound (?) Include, for example, phosgene, thiophosgene, diphenyl carbonate, diphenylthiocarbonate, bis (nitrophenyl) carbonate, bis (nitrophenyl) thiocarbonate, dimethyl carbonate, dimethylthiocarbonate, Diethyl carbonate, diethyl thiocarbonate, ethylene carbonate, ethylene thiocarbonate, 1,1'-carbonylbis-1H-imidazole or 1,1'-thiocarbonylbis-1H-imidazole. Further, carbon oxide (carbon monoxide or carbon dioxide) may be used instead of the carbonyl compound (?). The compounds shown here are, for example, not particularly limited.

Examples of the alkali include basic organic compounds such as triethylamine, diisopropylethylamine and DMAP (4-N, N-dimethylaminopyridine), inorganic alkaline compounds such as sodium hydroxide and potassium carbonate, Metal hydrides and the like. The compounds shown here are, for example, not particularly limited.

Examples of the organic solvent include a solvent which does not affect the reaction, specifically, aromatic solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane and heptane, halogen solvents such as dichloromethane and 1,2-dichloroethane , Ether solvents such as tetrahydrofuran and 1,4-dioxane, and aprotic polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone and dimethylsulfoxide May be used singly or in combination. Their amount is arbitrary.

In addition, 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 formula (1) as the diamine component as a raw material. Examples of other diamine compounds include compounds represented by the above formula (2). The diamine compound represented by the formula (2) may be one kind or two or more kinds.

As described above, R ² in the formula (2) is preferably a single bond, -O- or a divalent organic group and is 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 monovalent organic group having 12 to 25 carbon atoms and having a hydrogen atom, an alkyl group having 1 to 22 carbon atoms or 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 formula (2) contributes to increasing the pretilt angle (inclination angle of the liquid crystal with respect to the liquid crystal alignment film) of the liquid crystal. Examples of the diamine compound include long chain alkyl groups, perfluoroalkyl groups, An aliphatic cyclic group, a substituent group combining these groups, a steroid skeleton, and the like.

The preferable size of the pretilt angle varies in various modes depending on the mode. However, by selecting the ratio of the diamine compound represented by the formula (2) to the diamine component as the raw material of the solvent-soluble polyimide, Angle 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%, of the diamine component as a raw material of the solvent-soluble polyimide.

In a diamine compound represented by the formula (2), a TN mode in which a comparatively low pretilt angle of 3 to 5 ° is required and an OCB mode in which a pretilt angle of 8 to 20 ° is required require a relatively low tilt- desirable.

At a relatively small tilt expression capability structure, R ² is -O- or -NHCO - (- CONH-) are preferred, of p is 0-1, formula and q is 0-1, r is 0 are preferred, and p And / or when q is 1, R ³ is preferably a straight chain alkyl having 1 to 12 carbon atoms, and when p = q = r = 0, R ³ is a straight chain alkyl group having a carbon number of 10 to 22 or a A monovalent organic group selected from organic groups having 12 to 25 carbon atoms is preferable. The specific structure of the diamine compound represented by the formula (2) having a small tilting ability is shown in Table 1, but it is not limited thereto.

[Table 1]

Other diamine compounds other than the diamine compound represented by the formula (1) which may contain a diamine component which is a raw material of the solvent-soluble polyimide of the present invention include p-phenylenediamine, 2,3,5,6-tetra Dimethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl- Diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, Diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-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'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,2'-diamino Diphenyl ether, 2,3'-diaminodiphenyl ether, 4,4'-sulfonyldiamine, 3,3'-sulfonyldiamine, bis (4-aminophenyl) silane, bis , Dimethyl-bis (4-aminophenyl) silane, dimethyl-bis (3-aminophenyl) silane, 4,4'- thiodianiline, 3,3'-thiodianiline, Amine, 3,3'-diaminodiphenylamine, 3,4'-diaminodiphenylamine, 2,2'-diaminodiphenylamine, 2,3'-diaminodiphenylamine, N-methyl Diaminodiphenyl) amine, N-methyl (3,3'-diaminodiphenyl) amine, N-methyl (3,4'- 2'-diaminodiphenyl) amine, N-methyl (2,3'-di Aminodiphenyl) amine, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 1,4-diaminonaphthalene, 2,2'- Diaminobenzophenone, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 1,8-diaminonaphthalene, 2,5- Diaminonaphthalene, 2,8-diaminonaphthalene, 1,2-bis (4-aminophenyl) ethane, 1,2-bis Bis (4-aminophenyl) propane, 1,4-bis (4-aminophenyl) butane, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, Benzene, 1,4-bis (4-aminobenzyl) benzene, 1,3-bis (4-aminophenyl) benzene, ) Benzene, 4,4 '- [1,4-phenylenebis (methylene)] di (1, 3-phenylenebis (methylene)] dianiline, 3,4 '- [1,4-phenylenebis (methylene)] dianiline, 3,4' Phenylenebis (methylene)] dianiline, 3,3 '- [1,4-phenylenebis (methylene)] dianiline, 3,3' - [ Aniline, 1,4-phenylenebis [(4-aminophenyl) methanone], 1,4-phenylenebis [(3-aminophenyl) methanone], 1,3- Phenylene) methanone], 1,3-phenylenebis [(3-aminophenyl) methanone], 1,4-phenylenebis (4-aminobenzoate) (3-aminobenzoate), bis (4-aminophenyl) terephthalate, bis (3-aminophenyl) (4-aminophenyl) isophthalate, bis (3-aminophenyl) isophthalate, N, N ' - (1,3-phenylene) bis (4-aminobenzamide), N, N ' Bis (3-aminobenzamide), N, N'-bis (4-aminophenyl) terephthalamide, N, N'-bis Aminophenyl) isophthalamide, N, N'-bis (3-aminophenyl) isophthalamide, 9,10-bis Bis (4-aminophenoxy) phenyl] propane, 2,2'-bis [4- (4 (Aminophenoxy) phenyl] hexafluoropropane, 2,2'-bis (4-aminophenyl) hexafluoropropane, 2,2'- Bis (4-aminophenyl) propane, 2,2'-bis (3-aminophenyl) propane, 2,2'-bis (4-aminophenoxy) propane, 1,3-bis (3-aminophenoxy) propane, 1,4-bis ) Butane, 1,4-bis (3-aminophenoxy) butane, 1,5- Bis (4-aminophenoxy) pentane, 1,6-bis (3-aminophenoxy) pentane, Bis (4-aminophenoxy) heptane, 1,7-bis (4-aminophenoxy) heptane, (Aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,9- (3-aminophenoxy) undecane, 1,11- (4-aminophenoxy) undecane, 1,11- (Aminomethyl) aniline, 4- (2-amino) aniline, 3- (aminomethyl) (4-aminocyclohexyl) methane or bis (4-amino-3-methylcyclohexyl) methane, and alicyclic diamines such as 1,3 - diaminopropane, 1,4-diaminobutane, 1,5-diamino Pentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11- And aliphatic diamines such as 1,12-diaminododecane.

The above-mentioned other diamine compound may be used alone or in combination of two or more thereof, depending on the properties such as liquid crystal alignability, voltage retention rate, and accumulated charge when used as a liquid crystal alignment film.

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 formula (1) is part of the raw material. It is usually obtained by reacting a diamine component and a tetracarboxylic acid component. In general, first, a polyamic acid is obtained by reacting at least one tetracarboxylic acid component selected from the group consisting of a tetracarboxylic acid and a derivative thereof and a diamine component composed of one or more kinds of diamine compounds. In order to obtain a polyamic acid ester, a method of converting a carboxyl group of a polyamic acid into an ester is used. Polyimide can be obtained by imidizing a polyimide precursor such as polyamic acid or polyamic acid ester.

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

[Chemical Formula 5]

(Z ₁ in the formula (3) is a quadrivalent organic group having 4 to 13 carbon atoms and containing a non-aromatic cyclic hydrocarbon group having 4 to 6 carbon atoms)

Specific examples of Z ₁ in the formula (3) include quaternary organic groups represented by the following formulas (3a) to (3j).

[Chemical Formula 6]

(Formula (3a) of the Z ₂ ~ Z ₅ is a hydrogen atom, a methyl group, a chlorine atom or a benzene ring, and be the same or different in each occurrence, formula (3g) of Z ₆ and Z ₇ is a hydrogen atom or a methyl group, each of They may be the same or different)

A particularly preferable structure of Z _{1 in} the formula (3) is a formula (3a), a formula (3c), a formula (3d), a formula (3e), a formula (3f) or a formula (3g) . Among them, the formula (3a), the formula (3e), the formula (3f) or the formula (3g) is preferable.

The ratio of the tetracarboxylic acid dianhydride represented by the above formula (3) to the total amount of the tetracarboxylic acid component which is the raw material of the solvent-soluble polyimide is not particularly limited. For example, the tetracarboxylic acid component The tetracarboxylic acid dianhydride represented by the above formula (3) may be used alone. Of course, the tetracarboxylic acid component, which is a raw material of the solvent-soluble polyimide, is preferably tetracarboxylic acid or tetracarboxylic acid other than the tetracarboxylic acid dianhydride represented by the formula (3) as long as the effect of the present invention is not impaired Or an acid derivative. At this time, it is preferable that 1 mol% or more of the total amount of the tetracarboxylic acid component is tetracarboxylic acid dianhydride represented by the formula (3), more preferably 5 mol% or more, still more preferably 10 mol% Or more.

Other tetracarboxylic acid dianhydrides other than the tetracarboxylic acid dianhydrides represented by the formula (3) include pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6- Naphthalene tetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7-anthracenetetracarboxylic acid, 1,2,5,6-anthracenetetracarboxylic acid, 3, Biphenyltetracarboxylic acid, bis (3,4-dicarboxyphenyl) ether, 3,3 ', 4,4'-biphenyltetracarboxylic acid, Bis (3,4-dicarboxyphenyl) sulfone, bis (3,4-dicarboxyphenyl) methane, 2,2- Bis (3,4-dicarboxyphenyl) propane, bis (3,4-dicarboxyphenyl) dimethylsilane, bis -Dicarboxyphenyl) diphenylsilane, 2,3,4,5-pyridine tetracarboxylic acid, 2,6-bis (3,4-dicarboxyphenyl) pyridine, 3,3 ', 4,4'-di Phenylsulfone tetracar Acids, 3,4,9,10-perylene tetracarboxylic acid there may be mentioned, or 1,3-diphenyl-1,2,3,4-cyclobutane tetracarboxylic acid.

The tetracarboxylic acid dianhydrides and other tetracarboxylic acids and tetracarboxylic acid derivatives represented by the above formula (3) can be classified into one kind of tetracarboxylic acid and tetracarboxylic acid derivative depending on desired characteristics such as liquid crystal alignment property, voltage holding ratio, Or two or more kinds may be mixed and used.

The reaction of the diamine component and the tetracarboxylic acid component is usually carried out in an organic solvent. The organic solvent to be used at this time is not particularly limited as long as it dissolves the polyimide precursor such as the produced polyamic acid. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, Methyl ethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone, methyl cellosolve, methyl isobutyl ketone, methyl isobutyl ketone, methyl isobutyl ketone, methyl isobutyl ketone, But are not limited to, sorbose, ethylcellosolve, methylcellosolve acetate, ethylcellosolve acetate, butylcarbitol, ethylcarbitol, 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 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, N-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, isopropanol, n-butanol, isobutanol, Propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propyl acetate Glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3- Propyl 3-methoxypropionate, diglyme or 4-hydroxy-4-methyl-2-pentanone. These may be used alone or in combination. The solvent may be a solvent that does not dissolve the polyimide precursor, or may be mixed with the solvent to the extent that the resulting polyimide precursor does not precipitate. In addition, water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the resulting polyimide precursor, and therefore, the organic solvent is preferably dehydrated and dried.

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 an organic solvent is stirred and the tetracarboxylic acid component is added as it is or dispersed or dissolved in an organic solvent A method in which a diamine component is added to a solution in which a tetracarboxylic acid component is dispersed or dissolved in an organic solvent, a method in which a tetracarboxylic acid component and a diamine component are alternately added, and the like. May be used. When a plurality of diamine components or tetracarboxylic acid components are used for the reaction, they may be reacted in a preliminarily mixed state, or they may be sequentially reacted individually, or the low molecular weight compounds reacted individually may be mixed and reacted. The polymerization temperature at that time may be any temperature between -20 DEG C and 150 DEG C, but is preferably in the range of -5 DEG C to 100 DEG C. If the concentration is excessively low, it becomes difficult to obtain a polyimide precursor having a high molecular weight (and hence polyimide). If the concentration is too high, the viscosity of the reaction solution becomes excessively high, It becomes difficult. Therefore, the total concentration of the diamine component and the tetracarboxylic acid component in the reaction mixture is preferably 1 to 50 mass%, more preferably 5 to 30 mass%. In the initial stage of the reaction, it is carried out at a high concentration, and then an organic solvent can be added.

In the polymerization of the polyimide precursor such as polyamic acid, the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic acid component is preferably 0.8 to 1.2. As in the case of the usual polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the resulting polyimide precursor.

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

(7)

(Wherein R ₁₁ is a tetravalent organic group, R ₁₂ is a divalent organic group derived from a diamine component as a raw material, A ₁₁ and A ₁₂ are each a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, Or may be different, and j represents a positive integer)

In the above formula [a], each of R ₁₁ and R ₁₂ may be a single kind and may be a polymer having the same repeating unit, and may be a polymer having repeating units having a structure in which plural kinds of R ₁₁ and R ₁₂ are highly different.

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. R ₁₂ is a group derived from a diamine component represented by the following formula [b], for example, a raw material, for example, when R ₁₂ is a group derived from a diamine compound 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 -.

[Chemical Formula 8]

(Wherein R ₁₁ and R ₁₂ in the formula [b] and the formula [c] are the same as defined in the formula [a]

Then, polyimide is obtained by dehydrating and ring closure of such a polyimide precursor.

Examples of the method for imidizing the polyimide precursor include thermal imidization for directly heating the solution of the polyimide precursor or catalyst imidization for adding a catalyst to a solution of the polyimide precursor.

When the polyimide precursor is thermally imidized in a solution, the temperature is preferably 100 占 폚 to 400 占 폚, preferably 120 占 폚 to 250 占 폚, and is preferably carried out while removing water generated by the imidization reaction out of the system.

The catalyst imidation of the polyimide precursor can be carried out 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 moles, preferably 2 to 20 moles, of the amide group, and the amount of the acid anhydride is 1 to 50 moles, preferably 3 to 30 moles, of the amide group. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine or trioctylamine, and among them, pyridine is preferable since it has a basicity suitable for promoting the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Of these, use of acetic anhydride is preferable because purification after completion of the reaction is facilitated. The imidization rate by the catalyst imidization can be controlled by adjusting the catalyst amount, the reaction temperature, and the reaction time.

In the case of recovering the polymer (polyimide) produced from the reaction solution of the polymer (polyimide), the reaction solution may be put into a solvent and precipitated. Examples of the solvent used in the precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene or water. The polymer precipitated by charging into a solvent can be recovered by filtration and then dried under normal pressure or reduced pressure at room temperature or by heating. In addition, by repeating the operation of redissolving the polymer recovered and recovered in an organic solvent and re-precipitating and recovering the polymer solution 2 to 10 times, impurities in the polymer can be reduced. As the solvent at this time, for example, alcohols, ketones, hydrocarbons and the like can be mentioned, and when three or more kinds of solvents selected from these solvents are used, the purification efficiency is further increased, which is preferable.

The dehydration / decomposition rate (imidization rate) of the amide acid group of the solvent-soluble polyimide contained in the liquid crystal aligning agent of the present invention does not necessarily have to be 100%, but may be arbitrarily selected depending on the purpose and purpose in the range of 0% to 100% , Preferably 50% to 90%, and more preferably 82% to 86%.

The molecular weight of the solvent-soluble polyimide is preferably in the range of from 0.1 to 10 parts by weight, more preferably from 0.5 to 10 parts by weight, more preferably from 0.1 to 50 parts by weight, The molecular weight is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000.

<Polyamic acid>

The polyamic acid (also referred to as 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 a tetracarboxylic acid and a derivative thereof and a diamine component.

Examples of the diamine compound contained in the diamine component as the raw material of the polyamic acid include p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl- m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 2,5-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- 3,3'-dicarboxy-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-biphenyl, 3,3'-trifluoromethyl- 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'-sulfonyldiamine, 3,3'-sulfonyldiamine, bis (4- (Aminophenyl) silane, bis (3-aminophenyl) silane, dimethyl-bis (4-aminophenyl) silane, Diaminodiphenylamine, 3,3'-diaminodiphenylamine, 3,4'-diaminodiphenylamine, 2,2'-diaminodiphenylamine, 2, 3'-diaminodiphenylamine, (3,3'-diaminodiphenyl) amine, N-methyl (3,4'-diaminodiphenyl) amine, N'- Diaminodiphenyl) amine, N-methyl (2,2'-diaminodiphenyl) amine, N-methyl (2,3'-diaminodiphenyl) amine, 4,4'-diaminobenzophenone, , 3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 1,4 Diaminobenzophenone, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 1, Diaminonaphthalene, 2,6-diaminonaphthalene, 2,8-diaminonaphthalene, 1,2-bis (4-aminophenyl) Ethane, 1,2-bis (3-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,3- Phenyl) butane, 1,4-bis (3-aminophenyl) butane, bis (3,5-diethyl- Benzene, 1,4-bis (4-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, (4-aminophenoxy) benzene, 4,4 '- [1,4-phenylenebis (methylene)] dianiline, 4,4' - [ ] Dianiline, 3,4 '- [1,4-phenylenebis (methylene)] dianiline, 3,4' - [ Phenylenebis (methylene)] dianiline, 3,3 '- [1,4-phenylenebis (methylene)] dianiline, 3,3' - [ , 4-phenylenebis [(4-aminophenyl) methanone], 1,4-phenylenebis [(3-aminophenyl) methanone] Phenylenebis (3-aminophenyl) methanone], 1,4-phenylenebis (4-aminobenzoate), 1,4-phenylenebis , 1,3-phenylene bis (4-aminobenzoate), 1,3-phenylene bis (3-aminobenzoate), bis (4-aminophenyl) terephthalate, bis N, N ', N'-bis (4-aminophenyl) isophthalate, bis (3-aminophenyl) isophthalate, N, N '- (1,3-phenylene) bis (4-aminobenzamide) Bis (3-aminobenzamide), N, N'-bis (4-aminophenyl) terephthalate (3-aminophenyl) isophthalamide, N, N'-bis (4-aminophenyl) isophthalamide, N, N'- Bis (4-aminophenoxy) phenyl] propane, 2, 2'-bis Bis (4-aminophenoxy) phenyl] hexafluoropropane, 2,2'-bis (4-aminophenyl) hexafluoropropane, 2,2'-bis Bis (4-aminophenyl) propane, 2,2'-bis (3-amino (3-aminophenoxy) propane, 1,3-bis (3-aminophenoxy) propane, Bis (4-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,5-bis Phenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,6- Heptane, 1,7-bis (4-aminophenoxy) heptane, 1,8-bis (4-aminophenoxy) , 1,9-bis (3-aminophenoxy) nonane, 1,10- (4-aminophenoxy) 1,10- (3-aminophenoxy) decane, 1,11- (3-aminophenoxy) undecane, 1,12- 3- (aminomethyl) methylene) - (4-aminophenoxy) dodecane, 1,12- (4-aminocyclohexyl) methane or bis (4-amino-3-methylcyclohexyl) methane, etc., such as aniline, 4- (2-aminoethyl) aniline or 3- 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-dia Mino octane, 1,9-diaminononane, 1,10-diamino Aliphatic diamines such as 1,1-diamino dodecane and 1,12-diaminododecane, and heterocyclic diamines such as 3,5-diamino-N- (pyridin-3-ylmethyl) The flow can also be illustrated.

The diamine compound may be used alone or in combination of two or more thereof depending on the properties such as liquid crystal alignability, voltage retention rate, and accumulated charge when used as a liquid crystal alignment film.

As the tetracarboxylic acid component which is a raw material of the polyamic acid, it is preferable to use the tetracarboxylic acid dianhydride represented by the above formula (3). Especially preferred structures of Z _{1 in} the formula (3) in the tetracarboxylic acid component as the raw material of the polyamic acid are those of the formulas (3a), (3c), (3d) 3e), (3f) or (3g). Among them, the formula (3a), the formula (3e), the formula (3f) or the formula (3g) is preferable.

The ratio of the tetracarboxylic acid dianhydride represented by the formula (3) to the total amount of the tetracarboxylic acid component as the raw material of the polyamic acid is not particularly limited. For example, Or a tetracarboxylic acid dianhydride represented by the following formula (3). Of course, the tetracarboxylic acid component, which is a raw material of the solvent-soluble polyimide, is preferably tetracarboxylic acid or tetracarboxylic acid other than the tetracarboxylic acid dianhydride represented by the formula (3) as long as the effect of the present invention is not impaired Or an acid derivative. At this time, it is preferable that 1 mol% or more of the total amount of the tetracarboxylic acid component is tetracarboxylic acid dianhydride represented by the formula (3), more preferably 5 mol% or more, still more preferably 10 mol% or more to be.

Other tetracarboxylic acid dianhydrides other than the tetracarboxylic acid dianhydrides represented by the formula (3) include pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6- Naphthalene tetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7-anthracenetetracarboxylic acid, 1,2,5,6-anthracenetetracarboxylic acid, 3, Biphenyltetracarboxylic acid, bis (3,4-dicarboxyphenyl) ether, 3,3 ', 4,4'-biphenyltetracarboxylic acid, Bis (3,4-dicarboxyphenyl) sulfone, bis (3,4-dicarboxyphenyl) methane, 2,2- Bis (3,4-dicarboxyphenyl) propane, bis (3,4-dicarboxyphenyl) dimethylsilane, bis -Dicarboxyphenyl) diphenylsilane, 2,3,4,5-pyridine tetracarboxylic acid, 2,6-bis (3,4-dicarboxyphenyl) pyridine, 3,3 ', 4,4'-di Phenylsulfone tetracar Acids, 3,4,9,10-perylene tetracarboxylic acid there may be mentioned, or 1,3-diphenyl-1,2,3,4-cyclobutane tetracarboxylic acid.

The tetracarboxylic acid dianhydrides and other tetracarboxylic acids and tetracarboxylic acid derivatives represented by the above formula (3) can be classified into one kind of tetracarboxylic acid and tetracarboxylic acid derivative depending on desired characteristics such as liquid crystal alignment property, voltage holding ratio, Or two or more kinds may be mixed and used.

The reaction of the diamine component and the tetracarboxylic acid component is usually carried out in an organic solvent. The organic solvent to be used at that time is not particularly limited as long as it dissolves the produced polyamic acid. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, Methyl ethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone, methyl cellosolve, methyl isobutyl ketone, methyl isobutyl ketone, methyl isobutyl ketone, methyl isobutyl ketone, But are not limited to, sorbose, ethylcellosolve, methylcellosolve acetate, ethylcellosolve acetate, butylcarbitol, ethylcarbitol, 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 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, N-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, isopropanol, n-butanol, isobutanol, Propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propyl acetate Glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3- Propyl 3-methoxypropionate, diglyme or 4-hydroxy-4-methyl-2-pentanone. These may be used alone or in combination. Also, a solvent which does not dissolve the polyamic acid may be used in the solvent in a range in which the produced polyamic acid is not precipitated. In addition, water in the organic solvent inhibits the polymerization reaction, and further causes hydrolysis of the resulting polyamic acid, and therefore, it is preferable to use an organic solvent which is dehydrated and dried.

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 an organic solvent is stirred and the tetracarboxylic acid component is added as it is or dispersed or dissolved in an organic solvent A method in which a diamine component is added to a solution in which a tetracarboxylic acid component is dispersed or dissolved in an organic solvent, a method in which a tetracarboxylic acid component and a diamine component are alternately added, and the like. May be used. When a plurality of diamine components or tetracarboxylic acid components are used for the reaction, they may be reacted in advance in a mixed state, or they may be sequentially reacted individually, or the low molecular weight compounds reacted individually may be mixed and reacted. The polymerization temperature at that time may be any temperature between -20 DEG C and 150 DEG C, but is preferably in the range of -5 DEG C to 100 DEG C. The reaction can be carried out at an arbitrary concentration. However, if the concentration is too low, it becomes difficult to obtain a polyamic acid having a high molecular weight. If the concentration is too high, the viscosity of the reaction liquid becomes excessively high and it becomes difficult to perform uniform stirring. Therefore, the total concentration of the diamine component and the tetracarboxylic acid component in the reaction mixture is preferably 1 to 50 mass%, more preferably 5 to 30 mass%. In the initial stage of the reaction, it is carried out at a high concentration, and then an organic solvent can be added.

In the polymerization reaction of the polyamic acid, the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic acid component is preferably 0.8 to 1.2. As with the conventional polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the produced polyamic acid.

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

[Chemical Formula 9]

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

In the formula [d], each of R ²¹ and R ²² may be a single kind and may be a polymer having the same repeating unit, and a polymer having repeating units having a structure in which plural kinds of R ²¹ and R ²² are highly different.

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

[Chemical formula 10]

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

In the case of recovering the resulting polymer (polyamic acid) from the reaction solution of the polymer (polyamic acid), the reaction solution may be put into a solvent and precipitated. Examples of the solvent used in the precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene or water. The polymer precipitated by charging into a solvent can be recovered by filtration and then dried under normal pressure or reduced pressure at room temperature or by heating. In addition, by repeating the operation of redissolving the polymer recovered and recovered in an organic solvent and re-precipitating and recovering the polymer solution 2 to 10 times, impurities in the polymer can be reduced. As the solvent at this time, for example, alcohols, ketones, hydrocarbons and the like can be mentioned, and when three or more kinds of solvents selected from these solvents are used, the purification efficiency is further increased, which is preferable.

The molecular weight of the polyamic acid is preferably 5,000 to 1,000,000 in terms of weight average molecular weight measured by GPC (Gel Permeation Chromatography) in consideration of the strength of the resultant polymer film, the workability in forming the polymer film, and the uniformity of the polymer film And more preferably from 10,000 to 150,000.

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

<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 solvent-soluble polyimide or polyamic acid, and examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, Pyrrolidone, N-vinylpyrrolidone, dimethylsulfoxide, tetramethylurea, pyridine, dimethylpyrrolidone, N-methylpyrrolidone, N-methyl- Sulfone, hexamethyl sulfoxide,? -Butyrolactone, 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone , Organic solvents such as ethylene carbonate, propylene carbonate, diglyme and 4-hydroxy-4-methyl-2-pentanone. 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 intended liquid crystal alignment film.

As described above, when the diamine compound represented by the formula (1) is used as a liquid crystal aligning agent containing a solvent-soluble polyimide, a polyamic acid and a solvent, which are used in at least a part of the raw material, Is suppressed and the backlighting resistance when the liquid crystal alignment film is used is excellent. Therefore, a liquid crystal alignment film excellent in uniformity and transparency can be produced even if the time of leaving after application, for example, to a substrate is lengthened. Further, since this liquid crystal alignment film is excellent in backlight resistance, it is possible to provide a liquid crystal display device having suppressed deterioration of electrical characteristics due to irradiation of a backlight and having excellent electrical characteristics.

The whitening occurs when the solvent absorbs moisture in the air and the solubility of the polymer contained in the liquid crystal aligning agent is lowered. In the case of a liquid crystal aligning agent containing a solvent-soluble polyimide and a polyamic acid, a solvent-soluble polyimide having solubility in a solvent or water lower than that of 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 formula (1), and the structure of the diamine compound represented by the formula (1) has a large polarization. Therefore, the solvent-soluble polyimide contained in the liquid crystal aligning agent of the present invention has a higher solubility in solvents and water than a polyimide in which the diamine compound represented by the formula (1) is not used as a raw material. The solvent-soluble polyimide contained in the liquid crystal aligning agent of the present invention has NH of a urea structure derived from the diamine compound represented by the formula (1). The compatibility of the solvent-soluble polyimide with the polyamic acid is improved by bonding NH 2 derived from the urea structure of the solvent-soluble polyimide to the carboxyl group of the polyamic acid through noncovalent bonding such as hydrogen bonding. In this manner, the solubility of the solvent-soluble polyimide in the solvent and water is improved, and the compatibility of the solvent-soluble polyimide and the polyamic acid is improved, whereby the stability of the solvent-soluble polyimide in the liquid crystal aligning agent is remarkably improved, It is presumed that even if the solvent absorbs moisture in the air and the solubility of the solvent-soluble polyimide is somewhat lowered, the precipitation of the solvent-soluble polyimide is suppressed and the whitening is suppressed. In addition, the suppression effect of the whitening exhibited by the liquid crystal aligning agent of the present invention is at a level that can not be exerted only by improvement of the solubility of the electron-withdrawing 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 polyimide having a higher solubility in solvents or water than the solvent-soluble polyimide contained in the liquid crystal aligning agent of the present invention can improve the whitening There was no number. 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 is improved but also the compatibility of the solvent-soluble polyimide and the polyamic acid is improved, so that whitening can be remarkably suppressed I can tell.

The present invention is also excellent in backlight resistance as described above. Therefore, in the present invention, when a liquid crystal aligning agent is applied to a substrate, a large amount of solvent-soluble polyimide generally having stronger backlight resistance than polyamic acid is present at the interface with the liquid crystal on the opposite side to the substrate of the coated film . For example, 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 of the polyamic acid and the solvent-soluble polyimide is improved, it is considered that when the liquid crystal aligning agent is applied to a substrate or the like, the two-layer separation of the polyamic acid layer and the polyimide layer becomes difficult. That is, when the compatibility of the polyamic acid and the solvent-soluble polyimide is improved, the solvent-soluble polyimide and the polyamic acid exist in an island form at the interface with the liquid crystal and the polyamic acid having weaker back- There is a high possibility that the backlight resistance is lowered. However, in the liquid crystal aligning agent of the present invention, the reasons are not clear, but it is a liquid crystal aligning agent containing a solvent-soluble polyimide and a polyamic acid, which is suppressed in whitening and also excellent in backlight resistance.

The effect of suppressing such whitening and having excellent backlight resistance can be attained only when a solvent-soluble polyimide in which the diamine compound represented by the formula (1) is used at least in part of the raw material and a liquid crystal aligning agent containing a polyamic acid It is an effect to be exercised. For example, as shown in Comparative Examples to be described later, instead of the diamine compound represented by the formula (1) as a raw material for the solvent-soluble polyimide, a 1- (4-aminobenzyl) -3- (4-aminophenylethyl) urea is used, the effect of suppressing the whitening of the present invention and having excellent backlight resistance is not obtained. In addition, the diamine compound represented by the formula (1) needs to be used as a raw material for a solvent-soluble polyimide, and the effect of the present invention can not be exerted even when used as a raw material for a polyamic acid.

&Lt; Components of other liquid crystal aligning agent &gt;

The liquid crystal aligning agent of the present invention may be only a solvent-soluble polyimide and a polyamic acid in which the polymer component is a diamine compound represented by the above formula (1) and used in at least a part of the starting material, and the diamine compound represented by the formula (1) Soluble polyimide and polyamic acid used in at least a part may be mixed with another polymer. At that time, the content of the other polymer is 0.5 to 15% by mass, preferably 1.0 to 10% by mass, based on the total amount of the solvent-soluble polyimide and polyamic acid used in at least a part of the raw material of the diamine compound represented by the formula (1) Mass%. Examples of the other polymer include a polyimide obtained from a diamine component containing no diamine compound represented by the formula (1) and a tetracarboxylic acid component. In addition, polymers other than polyamic acid and polyimide, specifically, polyamic acid ester, acrylic polymer, methacrylic polymer, polystyrene or polyamide may be mentioned.

The liquid crystal aligning agent of the present invention is an organic solvent (also referred to as a poor solvent) which improves the uniformity of the film thickness of the polymer film and the surface smoothness when the liquid crystal aligning agent is applied, as long as the effect of the present invention is not impaired ) Or a compound. Further, it may contain a compound for improving the adhesion between the liquid crystal alignment film and the substrate.

Specific examples of the poor solvent for improving the uniformity of the film thickness or the surface smoothness include isopropyl alcohol, methoxymethyl pentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, Ethyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, Propylene glycol monoacetate, 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, di Butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, n-hexane, n-pentane, n-pentane, n- Propyleneglycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, methyl ethyl ketone, ethyl lactate, ethyl lactate, ethyl lactate, methyl lactate, ethyl acetate, , Ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 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, lactic acid methyl ester, lactic acid ethyl ester, n-propyl lactate, Ester or lactic acid is an organic solvent having a low surface tension such as a child wheat ester.

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

Examples of the compound that improves film thickness uniformity and surface smoothness include a fluorine-based surfactant, a silicone-based surfactant, and a nonionic surface-active agent. More specifically, for example, there may be mentioned EF Top EF301, EF303 and EF352 (manufactured by Tohchem Products), Megafac F171, F173 and R-30 (manufactured by Dainippon Ink), Fluorad FC430 and FC431 (manufactured by Sumitomo 3M Limited) Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass). The ratio of these surfactants to be used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass based on 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

Examples of the compound that improves the adhesion between the liquid crystal alignment layer and the substrate include a functional silane-containing compound and an epoxy group-containing compound, and examples thereof include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2- Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxy Silane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N- ethoxycarbonyl- Ethoxysilane, N-triethoxysilylpropyl triethylenetriamine, N-trimethoxysilylpropyl triethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxy Silane-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9- Aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxy Silane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) Polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2, 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 a compound to be adhered to these substrates is used, it is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of the polymer component contained in the liquid crystal aligning agent. If the amount is less than 0.1 part by mass, the effect of improving the adhesion can not be expected, and if it is more than 30 parts by mass, the alignment property of the liquid crystal may be deteriorated.

To the liquid crystal aligning agent of the present invention may be added a dielectric material or a conductive material for the purpose of changing electric characteristics such as the dielectric constant and conductivity of the liquid crystal alignment film as long as the effect of the present invention is not impaired in addition to the above poor solvent and compound.

<Liquid Crystal Alignment Film / Liquid Crystal Display Device>

The liquid crystal aligning agent of the present invention can be used as a liquid crystal alignment film after being applied and baked on a substrate, and subjected to an orientation treatment by rubbing treatment, light irradiation and the like. Further, in the case of vertical alignment application, etc., it can be used as a liquid crystal alignment film without alignment treatment. The substrate to be used at this time is not particularly limited as long as it is a substrate having high transparency. In addition to the glass substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate can also be used. From the viewpoint of process simplification, it is preferable to use a substrate on which an ITO electrode or the like for liquid crystal driving is formed. In the reflection type liquid crystal display element, an opaque substrate such as a silicon wafer can be used only for a substrate on one side, and a material for reflecting light such as aluminum can be used as the electrode in this case.

The method of applying the liquid crystal aligning agent is not particularly limited, but industrially, screen printing, offset printing, flexographic printing, or inkjet printing is generally used. Other coating methods include a dipping method, a roll coater method, a slit coater method, a spinner method, and a spraying method, and they may be used depending on the purpose. The liquid crystal aligning agent of the present invention is capable of producing a liquid crystal alignment film excellent in uniformity and transparency even when the time for which the liquid crystal aligning agent is left to stand after being coated on a substrate or the like is suppressed because whitening is suppressed.

After the liquid crystal aligning agent is coated on the substrate, the solvent is evaporated at 50 to 300 ° C, preferably 80 to 250 ° C by a heating means such as a hot plate, a heat circulation type oven or an IR (infrared) An orientation film (polymer film). When the thickness of the liquid crystal alignment layer after firing is too large, the power consumption of the liquid crystal display element is disadvantageously deteriorated. When the thickness is too thin, the reliability of the liquid crystal display element may deteriorate. Therefore, the thickness is preferably 5 to 300 nm, 10 to 100 nm. When the liquid crystal is horizontally or tilted, the fired liquid crystal alignment film is treated by rubbing, polarized ultraviolet irradiation, or the like.

In the liquid crystal display element of the present invention, a substrate on which a liquid crystal alignment film is formed from the liquid crystal aligning agent of the present invention is obtained by the above-described technique, and then a liquid crystal cell is produced by a known method to obtain a liquid crystal display element. A liquid crystal layer formed between the substrate and the liquid crystal layer and having the liquid crystal alignment layer formed by the liquid crystal aligning agent of the present invention; Display device. The liquid crystal display of the present invention may be a liquid crystal display device of a twisted nematic (TN) type, a vertical alignment (VA) type, an in-plane switching (IPS) Optically Compensated Bend) and the like.

As a method of manufacturing a liquid crystal cell, 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 the substrate of one substrate, and the substrates of the other substrate are bonded ), A method in which the liquid crystal is injected under reduced pressure, or a method in which a liquid crystal is dropped on the surface of the liquid crystal alignment film on which the spacer is dispersed, and the substrate is then subjected to sealing to perform sealing.

Examples of the liquid crystal include a positive type liquid crystal having positive dielectric anisotropy and a negative type liquid crystal having negative dielectric anisotropy. More specifically, for example, MLC-2003, MLC-6608, MLC- 6609 and the like are used.

As described above, the liquid crystal display device manufactured using the liquid crystal aligning agent of the present invention has excellent reliability because it has a liquid crystal alignment film excellent in backlight resistance, and can be preferably used for a liquid crystal television having a large screen and a high definition.

Example

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited at all by these examples.

The abbreviations used in this embodiment are as follows.

 (Tetracarboxylic acid dianhydride)

CBDA: 1,2,3,4-Cyclobutane tetracarboxylic acid dianhydride

TDA: 3,4-Dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic acid dianhydride

PMDA: pyromellitic acid dianhydride

 (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

? -BL:? -butyrolactone

&Lt; Measurement of molecular weight &

The molecular weight of the polymer (polyimide, polyamic acid) obtained by the polymerization reaction was measured by GPC (room temperature gel permeation chromatography) apparatus, and the number average molecular weight and the weight average molecular weight were measured as polyethylene glycol and polyethylene oxide conversion Respectively.

GPC apparatus: manufactured by Shodex Corp. (GPC-101)

Column: manufactured by Shodex Co., Ltd. (serial of KD803, KD805)

Column temperature: 50 ° C

30 mmol / l of lithium bromide-hydrate (LiBr.H ₂ O), 30 mmol / l of phosphoric anhydride crystal (o-phosphoric acid), 30 ml of tetrahydrofuran (THF) 10 ml / l)

Flow rate: 1.0 ml / min

Standard samples for preparing calibration curves: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation; and polyethylene glycol (molecular weight: about 12,000, 4,000, 1,000) manufactured by Polymer Laboratories.

[Synthesis Example 1] BAPU: Synthesis of 1,3-bis (4-aminophenetyl) urea

(11)

(4-nitrophenyl) ethylamine hydrochloride [A] (52.50 g, 259 mmol) and bis (4-nitrophenyl) [B] carbonate (37.53 g, 123 mmol) in a nitrogen- ) And THF (tetrahydrofuran) (1877 g) were added, and thereto was added triethylamine (74.90 g, 740 mmol) and 4-N, N-dimethylaminopyridine (3.01 g, 24.7 mmol) Stirring was carried out with a stirrer. The reaction was followed by HPLC (high performance liquid chromatography). After completion of the reaction, the reaction solution was added to pure water (9 L) and stirred for 30 minutes. Thereafter, filtration was performed, and the filtrate was washed with pure water (1 L) to obtain a crude product of a white solid. The resultant white solid was dispersed and washed with methanol (488 g) using an ultrasonic device, followed by filtration and drying to obtain a dinitro compound [C] as a white solid (yield 42.3 g, yield 96%).

A mixture of the compound [C] (42.32 g, 118 mmol), 5% palladium carbon (5% Pd / C) (4.23 g) and 1,4-dioxane (2031 g) And the mixture was stirred at room temperature in the presence of hydrogen. The reaction was followed by HPLC. After completion of the reaction, the catalyst was filtered with celite. Thereafter, the solvent of the filtrate was distilled off under reduced pressure to obtain a crude product of a white solid. 2-propanol (85 g) was added to the obtained crude product, followed by dispersion washing with an ultrasonic device, followed by filtration and drying to obtain a white solid diamine compound BAPU (Yield 31.9 g, yield 91%).

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

[Chemical Formula 12]

4-nitrobenzylamine hydrochloride [D] (50.00 g, 265 mmol), pyridine (20.97 g, 265 mmol) and dichloromethane (750 g) were added to a four-necked flask under nitrogen atmosphere at room temperature, Or less. Then, a dichloromethane (150 g) solution of 4-nitrophenyl chloroformate [E] (53.43 g, 265 mmol) was added thereto, the reaction temperature was elevated to 23 ° C and stirred for 1 hour, . 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 mass% were added to perform filtration. The filtrate was stirred at room temperature, and the precipitated solid was filtered. The solid was washed with methanol (200 g) and dried to obtain a white solid compound [F] (yield 33.26 g, yield 40%). On the other hand, a saturated aqueous solution of sodium hydrogencarbonate (500 g) was added to the filtrate and washed. The organic layer was further washed with saturated brine (500 g) and dried with 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 further white solid compound [F] (yield 16.6 g, yield 20%).

(30.29 g, 150 mmol), compound [F] (45.18 g, 142 mmol) and THF (2260 g) were added to a four-necked flask under nitrogen atmosphere at room temperature, The reaction was carried out by adding triethylamine (43.23 g, 427 mmol) and 4-N, N-dimethylaminopyridine (1.74 g, 14.2 mmol) thereto. The reaction was followed by HPLC. After completion of the reaction, the reaction solution was added to pure water (10 L) and stirred for 30 minutes. Thereafter, filtration was performed, and the filtrate was washed with pure water (2 L) to obtain a crude product of a white solid. The resulting white solid was washed with 2-propanol (300 g), followed by filtration and drying to obtain dinitro compound [H] as white solid (yield 43.9 g, yield 90%).

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) And the mixture was stirred at room temperature in the presence of hydrogen. The reaction was followed by HPLC. After completion of the reaction, the catalyst was filtered with celite. Thereafter, the filtrate was distilled off under reduced pressure to obtain the crude product of a tea white solid. 2-Propanol (330 g) was added to the crude product, followed by dispersion washing with an ultrasonic device, followed by filtration and drying to obtain a diamine compound ABAPHU (yield 37.0 g, yield 90%) as a pale white solid.

(Preparation of polymer solution 1) TDA / BAPU (10) p-PDA (80) C18DAB

(0.0035 mol) of BAPU as a diamine component, 3.03 g (0.028 mol) of p-PDA and 1.31 g (0.0035 mol) of C18 DAB as a diamine component as a tetracarboxylic acid component, And reacted in 90.32 g of NMP at 50 占 폚 for 24 hours to obtain a polyamic acid solution (PAA-1).

50.00 g of NMP, 10.78 g of acetic anhydride and 5.02 g of pyridine were added to 30.00 g of the polyamic acid solution (PAA-1), and the mixture was stirred at room temperature for 30 minutes and then reacted at 40 DEG C for 3 hours with stirring. After completion of the reaction, 335 g of methanol was slowly added to precipitate the polymer. After stirring for 30 minutes, the solid was recovered by filtration. The resulting solid was sufficiently washed with methanol, and then vacuum-dried at 100 占 폚 to obtain a polyimide powder. The polyimide had a number average molecular weight of 10,600, a weight average molecular weight of 26,200, and an imidization ratio of 82%.

To the resulting polyimide powder, 30.01 g of? -BL was added and the mixture was stirred and dissolved at 50 占 폚 for 24 hours to confirm that it was completely dissolved. Then, 5.85 g of? -BL and 2% of? And the mixture was stirred at 50 占 폚 for 24 minutes to obtain a polyimide solution (SPI-1) having polyimide of 6.0% by mass and? -BL of 94% by mass.

(Preparation of polymer solution 2) TDA / BAPU (20) p-PDA (70) C18DAB

9.90 g (0.033 mol) of TDA as a tetracarboxylic acid component, 1.96 g (0.0066 mol) of BAPU as a diamine component, 2.50 g (0.023 mol) of p-PDA and 1.25 g (0.0033 mol) The reaction was carried out in 88.41 g of NMP at 50 占 폚 for 24 hours to obtain a polyamic acid solution (PAA-2).

To 50.00 g of the polyamic acid solution (PAA-2), 90.00 g of NMP, 18.11 g of acetic anhydride and 8.42 g of pyridine were added. The mixture was stirred at room temperature for 30 minutes and then reacted at 40 占 폚 for 3 hours with stirring. After completion of the reaction, 580 g of methanol was slowly injected to precipitate the polymer. After stirring for 30 minutes, the solid was recovered by filtration. The resulting solid was sufficiently washed with methanol, and then vacuum-dried at 100 占 폚 to obtain a polyimide powder. The polyimide had a number average molecular weight of 10,500, a weight average molecular weight of 25,200 and an imidization ratio of 84%.

To 6.02 g of the obtained polyimide powder, 69.23 g of? -BL was added and dissolved by stirring at 50 占 폚 for 24 hours to confirm that it was completely dissolved. Then, 22.41 g of? -BL and 2%? -BL solution of LS- And the mixture was stirred at 50 占 폚 for 24 minutes to obtain a polyimide solution (SPI-2) having a polyimide content of 6.0% by mass and a γ-BL content of 94% by mass.

(Preparation of polymer solution 3) TDA / BAPU (30) p-PDA (60) C18DAB

(0.031 mol) of TDA as a tetracarboxylic acid component, 2.77 g (0.0093 mol) of BAPU as a diamine component, 2.01 g (0.019 mol) of p-PDA and 1.17 g (0.0031 mol) of C18 DAB, And reacted in 86.38 g of NMP at 50 DEG C for 24 hours to obtain a polyamic acid solution (PAA-3).

50.50 g of NMP, 10.01 g of acetic anhydride and 4.65 g of pyridine were added to 30.00 g of the polyamic acid solution (PAA-3), stirred at room temperature for 30 minutes, and reacted at 40 占 폚 for 3 hours with stirring. After completion of the reaction, 580 g of methanol was slowly injected to precipitate the polymer. After stirring for 30 minutes, the solid was recovered by filtration. The resulting solid was sufficiently washed with methanol, and then vacuum-dried at 100 占 폚 to obtain a polyimide powder. The polyimide had a number average molecular weight of 12,000, a weight average molecular weight of 28,500, and an imidization ratio of 82%.

To the obtained polyimide powder, 30.59 g of? -BL was added, and the mixture was stirred at 50 占 폚 for 24 hours to dissolve the mixture. It was confirmed that the mixture was completely dissolved. Then, 6.55 g of? -BL and 2% And the mixture was stirred at 50 占 폚 for 24 minutes to obtain a polyimide solution (SPI-3) having polyimide of 6.0% by mass and? -BL of 94% by mass.

(Preparation of polymer solution 4) TDA / BAPU (50) p-PDA (40) C18DAB

9.30 g (0.031 mol) of TDA as a tetracarboxylic acid component, 4.63 g (0.016 mol) of BAPU as a diamine component, 1.35 g (0.012 mol) of p-PDA and 1.17 g (0.0031 mol) And reacted in 93.09 g of NMP at 50 占 폚 for 24 hours to obtain a polyamic acid solution (PAA-4).

45.00 g of NMP, 8.66 g of acetic anhydride and 4.03 g of pyridine were added to 30.00 g of the polyamic acid solution (PAA-4), stirred at room temperature for 30 minutes, and reacted at 40 DEG C for 3 hours with stirring. After completion of the reaction, 300 g of methanol was slowly injected to precipitate the polymer. After stirring for 30 minutes, the solid was recovered by filtration. The resulting solid was sufficiently washed with methanol, and then vacuum-dried at 100 占 폚 to obtain a polyimide powder. The polyimide had a number average molecular weight of 11,200, a weight average molecular weight of 25,200 and an imidization ratio of 82%.

To 2.60 g of the obtained polyimide powder, 29.90 g of? -BL was added and dissolved by stirring at 50 占 폚 for 24 hours to confirm that it was completely dissolved. Then, 4.00 g of? -BL and 2% of? And the mixture was stirred at 50 占 폚 for 24 minutes to obtain a polyimide solution (SPI-4) having polyimide of 6.0% by mass and? -BL of 94% by mass.

(Preparation of polymer solution 5) TDA / BAPU (90) C18DAB

, 7.50 g (0.025 mol) of TDA as a tetracarboxylic acid component, 6.71 g (0.023 mol) of BAPU as a diamine component, and 0.90 g (0.0025 mol) of C18 DAB as a diamine component were reacted in 86.23 g of NMP at 50 캜 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 the polyamic acid solution (PAA-5), stirred at room temperature for 30 minutes, and reacted at 40 占 폚 for 3 hours with stirring. After completion of the reaction, 320 g of methanol was slowly added to precipitate the polymer. After stirring for 30 minutes, the solid was recovered by filtration. The resulting solid was sufficiently washed with methanol, and then vacuum-dried at 100 占 폚 to obtain a polyimide powder. The polyimide had a number average molecular weight of 12,400, a weight average molecular weight of 27,400, and an imidization ratio of 82%.

30.71 g of? -BL and 4.76 g of? -BL were added to 2.67 g of the obtained polyimide powder and dissolved by stirring at 50 占 폚 for 24 hours to confirm that they were completely dissolved. 6.35 g of a 2% NMP solution of LS-2450 was added And stirred at 50 占 폚 for 24 minutes to obtain a polyimide solution (SPI-5) having polyimide of 6.0% by mass,? -BL of 69% by mass and NMP of 25% by mass.

(Preparation of polymer solution 6) TDA / p-PDA (90) C16DAB

A solution was prepared by dissolving 7.51 g (0.025 mol) of TDA as a tetracarboxylic acid component, 2.43 g (0.023 mol) of p-PDA as a diamine component and 0.87 g (0.0025 mol) And reacted for a time 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). The mixture was stirred at room temperature for 30 minutes, and then reacted at 40 占 폚 for 3 hours with stirring. After completion of the reaction, 214 g of methanol was slowly injected to precipitate the polymer. After stirring for 30 minutes, the solid was recovered by filtration. The resulting solid was sufficiently washed with methanol, and then vacuum-dried at 100 ° C to obtain a polyimide powder. The polyimide had a number average molecular weight of 12,400, a weight average molecular weight of 27,400 and an imidization ratio of 88%.

To 2.60 g of the obtained polyimide powder, 29.90 g of? -BL was added and dissolved by stirring at 50 占 폚 for 24 hours to confirm that it was completely dissolved. Then, 4.00 g of? -BL and 2% of? And the mixture was stirred at 50 占 폚 for 24 minutes to obtain a polyimide solution (SPI-6) having polyimide of 6.0% by mass and? -BL of 94% by mass.

(Preparation of polymer solution 7) CBDA (50) PMDA / DDM

BL 113.00 g and NMP 113.00 g, using 9.81 g (0.050 mol) of CBDA as a tetracarboxylic acid component, 10.25 g (0.047 mol) of PMDA and 19.83 g (0.0060 mol) of DDM as a diamine component, The mixture was reacted at room temperature for 3 hours to obtain a polyamic acid solution.

198.97 g of the obtained polyamic acid solution was diluted with 204.23 g of? -BL, 14.63 g of NMP and 73.74 g of BCS to obtain a solution containing 6 mass% of solids, 59 mass% of? -BL, 20 mass% of NMP, 15 mass % Polyamic acid solution (PAA-7). 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

(0.015 mol) of CBDA as a tetracarboxylic acid component and 1.56 g (0.014 mol) of p-PDA as a diamine component were reacted in 15.18 g of? -BL and 25.31 g of NMP at room temperature for 2 hours , 0.35 g (0.0018 mol) of a tetracarboxylic acid component CBDA, 0.72 g (0.036 mol) of a diamine component DDM and 10.12 g of γ-BL were added and reacted at room temperature for 3 hours to obtain a polyamic acid solution.

47.37 g of the obtained polyamic acid solution was diluted with 52.28 g of? -BL and 17.59 g of BCS to obtain a polyamic acid solution having a solid content of 4 mass%, a γ-BL content of 63 mass%, an NMP content of 18 mass%, and a BCS content of 15 mass% To obtain a solution (PAA-8). 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

(0.028 mol) of CBDA as a tetracarboxylic acid component and 1.04 g (0.0096 mol) of p-PDA as a diamine component were reacted in 23.8 g of? -BL and 14.28 g of NMP at room temperature for 2 hours , 0.94 g (0.0048 mol) of a tetracarboxylic acid component CBDA, 1.26 g (0.064 mol) of a diamine component DDM and 9.52 g of γ-BL were added and reacted at room temperature for 3 hours to obtain a polyamic acid solution.

46.38 g of the obtained polyamic acid solution was diluted with 20.64 g of? -BL and 11.83 g of BCS to obtain a polyamic acid solution having a solids content of 6 mass%, a γ-BL content of 53 mass%, an NMP content of 26 mass%, and a BCS content of 15 mass% 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

27.43 g of? -BL and 18.35 g of NMP were obtained by using 2.86 g (0.014 mol) of CBDA as a tetracarboxylic acid component, 1.09 g (0.0045 mol) of 3AMPDA as a diamine component and 1.13 g , And reacted at room temperature for 3 hours to obtain a polyamic acid solution.

43.49 g of the obtained polyamic acid solution was diluted with 21.82 g of? -BL and 11.52 g of BCS to obtain a polyamic acid solution having a solids content of 6 mass%, a γ-BL content of 59 mass%, an NMP content of 20 mass%, and a BCS content of 15 mass% 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

(0.042 mol) of CBDA as the tetracarboxylic acid component, 3.65 g (0.034 mol) of p-PDA as the diamine component, 0.68 g (0.0045 mol) of DBA and 0.92 g (0.0068 mol) of Me-3ABA , And reacted in 38.39 g of? -BL and 38.39 g of NMP at room temperature for 3 hours to obtain a polyamic acid solution.

80.90 g of the resulting polyamic acid solution was diluted with 84.95 g of? -BL, 6.07 g of NMP, and 30.33 g of BCS to obtain a solid content of 6 mass%, γ-BL of 59 mass%, NMP of 20 mass%, BCS of 15 mass % Polyamic acid solution (PAA-11). 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

A solution was prepared by dissolving 9.00 g (0.030 mol) of TDA as a tetracarboxylic acid component, 2.92 g (0.027 mol) of p-PDA as a diamine component and 1.13 g (0.0030 mol) And reacted for a time 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 polyamic acid solution (PAA-12), stirred at room temperature for 30 minutes, and reacted at 40 占 폚 for 3 hours with stirring. After completion of the reaction, 214 g of methanol was slowly injected to precipitate the polymer. After stirring for 30 minutes, the solid was recovered by filtration. The resulting solid was sufficiently washed with methanol, and then vacuum-dried at 100 ° C to obtain a polyimide powder. The polyimide had a number average molecular weight of 11,280, a weight average molecular weight of 29,100, and an imidization ratio of 85%.

To 2.60 g of the obtained polyimide powder, 29.00 g of? -BL was added and dissolved by stirring at 50 占 폚 for 24 hours to confirm that it was completely dissolved. Then, 4.00 g of? -BL and 2% of? 6.15 g, and the mixture was stirred at 50 占 폚 for 24 minutes to obtain a polyimide solution (SPI-7) having polyimide of 6.0% by mass and? -BL of 94% by mass.

(Preparation of polymer solution 13) TDA / ABAPHU (20) p-PDA (70) C18DAB

5.10 g (0.017 mol) of TDA as a tetracarboxylic acid component, 0.96 g (0.0034 mol) of ABAPHU as a diamine component, 1.29 g (0.012 mol) of p-PDA and 0.64 g (0.0017 mol) NM? Was reacted in 45.47 g at 50 占 폚 for 24 hours to obtain a polyamic acid solution (PAA-13).

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

36.92 g of? -BL was added to 3.21 g of the polyimide powder and dissolved by stirring at 50 占 폚 for 24 hours to confirm that it was completely dissolved. 7.75 g of? -BL, 9.86 g of NMP and 2% of LS- 8.08 g of the? -BL solution was added and stirred at 50 占 폚 for 24 minutes to obtain a polyimide solution (SPI-8) having polyimide of 5.0 mass%,? -BL of 80 mass% and NMP of 15 mass%.

(Example 1) Preparation of polymer solution 1 / Preparation of polymer solution 7 = 20/80

Preparation of Polymer Solution The polyimide solution (SPI-1) obtained in Preparation 1 and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution (PAA-7) were mixed at a mass ratio of 20: 80, and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 2) Preparation of polymer solution 2 / Preparation of polymer solution 7 = 20/80

Preparation of Polymer Solution The polyimide solution (SPI-2) obtained in Preparation 2 and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution (PAA-7) were mixed in a mass ratio of 20: 80, and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 3) Preparation of polymer solution 3 / Preparation of polymer solution 7 = 20/80

Preparation of Polymer Solution The polyimide solution (SPI-3) obtained in Preparation 3 and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution (PAA-7) were mixed so that the mass ratio thereof was 20:80 and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 4) Preparation of polymer solution 4 / Preparation of polymer solution 7 = 20/80

Preparation of Polymer Solution The polyimide solution (SPI-4) obtained in Preparation 4 and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution (PAA-7) were mixed so that the mass ratio thereof was 20: 80 and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 5) Preparation of polymer solution 5 / Preparation of polymer solution 7 = 20/80

Preparation of polymer solution The polyimide solution (SPI-5) obtained in Preparation 5 and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution (PAA-7) were mixed at a mass ratio of 20: 80, and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 6) Preparation of polymer solution 2 / Preparation of polymer solution 7 = 30/70

Preparation of Polymer Solution The polyimide solution (SPI-2) obtained in Preparation 2 and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution (PAA-7) were mixed at a mass ratio of 30:70 and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 7) Preparation of polymer solution 2 / Preparation of polymer solution 7 = 40/60

Preparation of Polymer Solution The polyimide solution (SPI-2) obtained in Preparation 2 and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution (PAA-7) were mixed at a mass ratio of 40:60 and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 8) Preparation of polymer solution 2 / Preparation of polymer solution 7 = 50/50

Preparation of Polymer Solution The polyimide solution (SPI-2) obtained in Preparation 2 and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution (PAA-7) were mixed at a mass ratio of 50:50 and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 9) Preparation of polymer solution 2 / Preparation of polymer solution 7 = 70/30

Preparation of Polymer Solution The polyimide solution (SPI-2) obtained in Preparation 2 and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution (PAA-7) were mixed at a mass ratio of 70:30, and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 10) Preparation of polymer solution 2 / Preparation of polymer solution 8 = 20/80

Preparation of Polymer Solution The polyimide solution (SPI-2) obtained in Preparation 2 and the polyamic acid solution (PAA-8) obtained in Preparation 8 of the polymer solution (PAA-8) were mixed so that the mass ratio thereof was 20: 80 and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 11) Preparation of polymer solution 2 / Preparation of polymer solution 9 = 20/80

Preparation of Polymer Solution The polyimide solution (SPI-2) obtained in Preparation 2 and the polyamic acid solution (PAA-9) obtained in Preparation 9 of the polymer solution (PAA-9) were mixed so that the mass ratio thereof was 20: 80 and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 12) Preparation of polymer solution 2 / Preparation of polymer solution 10 = 20/80

Preparation of Polymer Solution The polyimide solution (SPI-2) obtained in Preparation 2 and the polyamic acid solution (PAA-10) obtained in Preparation 10 of the polymer solution (PAA-10) were mixed in a mass ratio of 20: 80, and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Example 13) Preparation of polymer solution 2 / Preparation of polymer solution 11 = 20/80

Preparation of Polymer Solution The polyimide solution (SPI-2) obtained in Preparation 2 and the polyamic acid solution (PAA-11) obtained in Preparation 11 of the polymer solution (PAA-11) were mixed at a mass ratio of 20:80 and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Comparative Example 1) Preparation of polymer solution 12 / Preparation of polymer solution 7 = 20/80

Preparation of Polymer Solution The polyimide solution (SPI-7) obtained in Preparation 12 and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution (PAA-7) were mixed at a mass ratio of 20:80, and stirred at room temperature for 1 hour, To obtain an alignment agent.

(Comparative Example 2) Preparation of polymer solution 13 / Preparation of polymer solution 7 = 20/80

Preparation of Polymer Solution The polyimide solution (SPI-8) obtained in 13 and the polyamic acid solution (PAA-7) obtained in Preparation 7 of the polymer solution (PAA-7) were mixed at a mass ratio of 20:80 and stirred at room temperature for 1 hour, To obtain an alignment agent.

&Lt; Production of liquid crystal cell &

A liquid crystal aligning agent prepared in Examples 1 to 13 and a liquid crystal aligning agent prepared in Comparative Examples 1 and 2 were each prepared as follows.

The liquid crystal aligning agent was spin-coated on a glass substrate having a transparent electrode formed thereon, dried on a hot plate at 80 DEG C for 70 seconds, and then fired on a hot plate at 210 DEG C for 10 minutes to form a 100 nm thick coating film. The coated film surface was rubbed with a rubbing device having a roll diameter of 120 mm using a rayon cloth under the conditions of a roll revolution rate of 1000 rpm, a roll advancing speed of 50 mm / sec, and an indentation amount of 0.3 mm to obtain a substrate on which a liquid crystal alignment film was formed. Two substrates on which liquid crystal alignment films were formed were prepared, spacers having a size of 6 mu m were dispersed on one liquid crystal alignment film surface, and a sealant was printed thereon. And then adhered so as to be perpendicular to each other. Thereafter, the sealing agent was cured to prepare a public cell. A liquid crystal MLC-2003 (manufactured by Merck Japan Co.) was injected into this vacant 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 liquid crystal cell and the liquid crystal aligning agent thus prepared 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, respectively.

<Evaluation of whiteness>

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 thick Cr substrate and the time until the liquid crystal aligning agent was whitened under the conditions of a temperature of 23 캜 and a humidity of 65% . The results are shown in Table 2.

<Evaluation of Backlight Resistance by Measurement of Voltage Holding Ratio (VHR)> [

For each manufactured twisted nematic liquid crystal cell, the initial voltage maintaining ratio (VHR) in which no backlight was irradiated was measured. The voltage holding ratio was measured by applying a voltage of 4 V for 60 占 퐏 under a temperature of 90 占 폚, measuring the voltage after 166.7 ms and calculating the voltage holding ratio. For the measurement of the voltage holding ratio, a VHR-1 voltage maintenance ratio measuring apparatus manufactured by Toyota Technica was used.

Thereafter, each twisted nematic liquid crystal cell was left on a 40-inch type backlight module for a liquid crystal TV for 240 hours, and the voltage holding ratio was measured in the same manner as the measurement of the voltage holding ratio. The measurement results of the voltage holding ratio before being irradiated with the back light (indicated as &quot; BL before &quot; in Table 2) and the voltage holding ratio after the back light was irradiated for 240 hours .

As a result, as shown in Table 2, in Examples 1 to 13 in which the liquid crystal aligning agent containing polyimide and polyamic acid using the diamine compound represented by the formula (1) as a raw material was used, And the VHR reduction before and after the irradiation of the backlight was very small, so that the backlight resistance was excellent.

[Table 1-1]

[Table 1-2]

[Table 2]

Claims (6)

A liquid crystal aligning agent characterized by containing a solvent-soluble polyimide, a polyamic acid and a solvent, wherein at least a part of the starting material is a diamine compound represented by the following formula (1).
[Chemical Formula 1]

X ¹ (wherein 1 is an oxygen atom or a sulfur atom, Y ¹ is bonded with a single bond, -O-, -S- or -COO- * (However, the coupling hand is attached to R ¹ '*' ) And R &lt; ¹ &gt; is an alkylene group having 1 to 3 carbon atoms) The method according to claim 1,
A liquid crystal aligning agent characterized in that the diamine compound represented by the formula (1) is contained in an amount of 10 to 90 mol% of the diamine component as a raw material of the solvent-soluble polyimide. 3. The method according to claim 1 or 2,
A liquid crystal aligning agent characterized in that X ¹ in the formula (1) is an oxygen atom. 4. The method according to any one of claims 1 to 3,
Wherein the solvent-soluble polyimide is a diamine compound represented by the following formula (2) as a part of raw materials.
(2)

(2) wherein 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 cyclohexane ring, and p, q, And R ³ is a monovalent organic group having 12 to 25 carbon atoms and having a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or 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 having the liquid crystal alignment film according to claim 5.