KR101928350B1 - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display device - Google Patents

Abstract

(Problems to be solved) A liquid crystal aligning agent capable of obtaining a liquid crystal display element that not only has good printability but also maintains good electric characteristics even after a long time of driving.
The liquid crystal aligning agent is obtained by a method comprising the steps of: A) mixing at least one polymer (a) selected from the group consisting of A) a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine and a polyimide obtained by dehydrocondensing the polyamic acid, (B) at least one kind of solvent selected from the group consisting of C) 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone and compounds represented by the following formula (c).

Description

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

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film and a liquid crystal display element, and more particularly to a liquid crystal aligning agent for obtaining a liquid crystal display element having good printability and good electric characteristics after long driving, And a liquid crystal alignment film and a liquid crystal display device manufactured using the alignment agent.

Conventionally, as a liquid crystal display element, a horizontally aligned type such as a TN mode, an IPS mode and an FFS mode, and a vertically aligned type such as a VA mode are known. These liquid crystal display devices have a liquid crystal alignment film for aligning liquid crystal molecules. As a material of the liquid crystal alignment film, polyamic acid and polyimide are generally used in view of good heat resistance, mechanical strength, and various properties such as affinity with liquid crystal.

In recent years, liquid crystal display devices are used not only for display terminals such as personal computers, but also for various purposes such as liquid crystal televisions, car navigation systems, mobile phones, smart phones, and information displays. With such versatility, the liquid crystal display element may be used under conditions more severe than conventional ones in terms of driving time and the like. Therefore, as a liquid crystal display element, it is required that there is little decrease in display quality (less deterioration of electric characteristics) even when continuous driving is performed for a long time, and various liquid crystal aligning agents for obtaining such liquid crystal display elements have been proposed See, for example, Patent Document 1 or Patent Document 2).

Japanese Laid-Open Patent Publication No. 2010-97188 Japanese Laid-Open Patent Publication No. 2010-156934

However, in a liquid crystal display element, it is unavoidable that it deteriorates with use as with other polymer materials. In addition, among the deterioration, the deterioration of the oxidation caused by energy such as ultraviolet rays or heat is particularly serious. On the other hand, in recent years, for example, liquid crystal display elements are often driven for a long time, such as information displays. In this case, the oxidative deterioration progresses, and the electric characteristics of the liquid crystal display element are lowered. Therefore, in order to suppress oxidation deterioration of the liquid crystal display element, it is conceivable to include an antioxidant as an additive in the liquid crystal aligning agent. However, when an antioxidant is contained in the liquid crystal aligning agent, there arises a problem that the printability is lowered.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems described above, and it is an object of the present invention to provide a liquid crystal aligning agent capable of obtaining a liquid crystal display element which not only has good printability but also maintains good electrical properties even after a long driving time, And to provide a liquid crystal alignment film and a liquid crystal display element to be manufactured.

DISCLOSURE OF THE INVENTION The present inventors have intensively studied in order to achieve the problems of the prior art as described above. As a result, they found that the above problems can be solved by dissolving a polymer component and an antioxidant in a specific solvent to prepare a liquid crystal aligning agent, I have come to completion. Specifically, the following liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element are provided by the present invention.

(A) at least one polymer (a) selected from the group consisting of A) a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine and a polyimide obtained by dehydrocondylating the polyamic acid, and (B) (B) at least one solvent selected from the group consisting of (C) 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone and compounds represented by the following formula c). < / RTI >

(In the formula (1), R ¹ and R ² are each independently a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or a monovalent group containing -O- between carbon-carbon bonds of the hydrocarbon group, R ¹ and R ² may combine with each other to form a ring structure; and R ³ is an alkyl group having 1 to 6 carbon atoms).

According to the liquid crystal aligning agent of the present invention, by including the antioxidant (b), in the liquid crystal display element manufactured using the liquid crystal aligning agent, the peroxy radical or hydroperoxide generated in the liquid crystal or in the liquid crystal alignment film can be supplemented or decomposed It is possible to do. Thus, oxidation deterioration of the liquid crystal display element can be suppressed, and the electric characteristics can be maintained well after the liquid crystal display element is driven for a long time. Particularly, since the liquid crystal aligning agent of the present invention uses a specific solvent (c), the printing property is good even though it contains an antioxidant.

In one embodiment of the liquid crystal aligning agent of the present invention, the content of the solvent (c) is 5% by weight or more of the total solvent. In this case, the printability can be further improved.

In another embodiment, the tetracarboxylic acid dianhydride may be 2,3,5-tricarboxycyclopentylacetic acid dianhydride and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2 : 4,6: 8-2 An anhydride may be preferably used. When the tetracarboxylic dianhydride is the specific compound described above, the solubility of the polymer (a) in the solvent (c) becomes better and the printing property can be further improved.

In one embodiment of the liquid crystal aligning agent of the present invention, the antioxidant (b) is preferably at least one selected from the group consisting of a compound having a hindered amine structure and a compound having a hindered phenol structure. By using the above specific compound as the antioxidant, it is possible to suppress the deterioration of the electrical characteristics as much as possible by driving the liquid crystal display element for a long time.

Further, in one aspect, the present invention provides a liquid crystal alignment film formed by the above-described liquid crystal aligning agent and a liquid crystal display element comprising the liquid crystal alignment film. In the liquid crystal display device having the liquid crystal alignment film, the electric characteristics can be maintained satisfactorily even after driving for a long time.

(Mode for carrying out the invention)

<Liquid Crystal Aligner>

The liquid crystal aligning agent of the present invention comprises at least one polymer (a) selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine and a polyimide obtained by dehydrocondensing the polyamic acid, and an antioxidant (b ), And the polymer (a) and the antioxidant (b) are dissolved in a solvent. Hereinafter, the liquid crystal aligning agent of the present invention will be described in detail.

For polymer (a)

<Polyamic acid>

[Tetracarboxylic acid dianhydride]

Examples of the tetracarboxylic acid dianhydride used for synthesizing the polyamic acid in the present invention include aliphatic tetracarboxylic acid dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride . As specific examples of these,

Examples of the aliphatic tetracarboxylic acid dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride and the like;

As the alicyclic tetracarboxylic acid dianhydride, for example, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4, 5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2- c] furan-1,3-dione, , 5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [ (Tetrahydrofuran-2 ', 5'-dione), 5- (2,5-dioxotetrahydro-3 ' 3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-2 anhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-2 anhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane- , 5,8,10-tetraone, cyclohexanetetracarboxylic dianhydride and the like;

As the aromatic tetracarboxylic acid dianhydride, for example, pyromellitic dianhydride and the like; The tetracarboxylic acid dianhydride described in JP-A-2010-97188 can be used. The tetracarboxylic acid dianhydrides may be used singly or in combination of two or more.

The tetracarboxylic acid dianhydride used for synthesizing the polyamic acid preferably contains an alicyclic tetracarboxylic acid dianhydride in view of good solubility in a solvent. Examples of the alicyclic tetracarboxylic acid dianhydride include 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro- 3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro- -2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane- 2: 4,6: 8-2 anhydride, and 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride are preferable, and in view of good printing property, Tricarboxycyclopentyl acetic acid dianhydride, and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-2 anhydride.

As the tetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6,8-2 The total content of these compounds is preferably 10 mol% or more, more preferably 20 to 100 mol%, based on the total amount of the tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid. , And more preferably 50 to 100 mol%.

[Diamine]

Examples of the diamine used for synthesizing the polyamic acid in the present invention include aliphatic diamines, alicyclic diamines, aromatic diamines, diaminoorganosiloxanes, and the like. These diamines can be used singly or in combination of two or more. Specific examples of the diamine include aliphatic diamines such as 1,1-meta-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine and the like;

As the alicyclic diamine, for example, 1,4-diaminocyclohexane, 4,4'-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane and the like;

As aromatic diamines, for example, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 1,5-diaminonaphthalene, 2,2'-dimethyl Diaminobiphenyl, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 2,7-diaminofluorene, 4,4'-diamino Diphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9- 4,4'- (m-tert-butylphenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, Bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3,4 - diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacrylidine, 3,6-diaminocarbazole, N-methyl- , 6-diaminocarbazole, N-phenyl (4-aminophenyl) -N, N'-dimethylbenzidine, 1,4-diaminocyclohexane, N, N'- Aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, 1- (4-amino Phenyl) -2,3-dihydro-1,3,3-trimethyl-1 H-inden-6-amine, 3,5-diaminobenzoic acid, cholestanyloxy-3,5-diaminobenzene, cholesteryl Oxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestenyloxy-2,4-diaminobenzene, 3,5-diaminobenzoic acid cholestanyl, 3,5 (4-aminobenzoyloxy) cholestane, 3,6-bis (4-aminophenoxy) cholestane, 4-aminobenzoic acid cholestane, - (4'-trifluoromethoxybenzoyloxy) cyclohexyl-3,5-diaminobenzoate, 4- (4'-trifluoromethylbenzoyloxy) cyclohexyl-3,5-diaminobenzoate, 1 , 1-bis (4 - ((amino (4 - ((aminophenyl) methyl) phenyl) -4-heptylcyclohexane, 1,1-bis ) Methyl) phenyl) -4-heptylcyclohexane, 1,1-bis (4- (aminophenyl) methyl) , N-diallylamine, 4-aminobenzylamine, 3-aminobenzylamine and the following formula (A-1):

(Wherein X ^I and X ^II are each a single bond, -O-, -COO- or -OCO-, R ^I is an alkanediyl group having 1 to 3 carbon atoms, a is 0 or 1, b is an integer of 0 to 2, c is an integer of 1 to 20, n is 0 or 1, provided that a and b are not 0 at the same time)

And the like;

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

Examples of the divalent group represented by "-X ^I - (R ^I -X ^II ) _n -" in the above formula (A-1) include an alkanediyl group having 1 to 3 carbon atoms, * -O-, Or * -OC ₂ H ₄ -O- (provided that a bonding hand having "*" attached thereto is bonded to a diaminophenyl group). Specific examples of the group "-C _c H _{2c +1} " include a methyl group, an ethyl group, a n-propyl group, an n-butyl group, an n-pentyl group, n-heptadecyl, n-heptadecyl, n-octadecyl, n-hexadecyl, n-hexadecyl, An n-nonadecyl group, and an n-eicosyl group. Two amino groups of the diamino-phenyl group is preferably in the 2,4-position or 3,5-position with respect to the group "X ^I".

Specific examples of the compound represented by the formula (A-1) include compounds represented by the following formulas (A-1-1) to (A-1-3).

The diamine used in the synthesis of the polyamic acid in the present invention preferably contains an aromatic diamine (diamine having an amino group bonded to an aromatic ring) in an amount of 30 mol% or more, more preferably 50 mol% or more , And particularly preferably 80 mol% or more.

When synthesizing a polyamic acid contained in a liquid crystal aligning agent for a vertically aligned pattern, those having a pretilt component as the diamine may be used in order to impart good vertical alignment properties. Specific examples of the diamine having such a pretilt component include dodecanoxy-2,4-diaminobenzene, tetradecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene , Hexadecaneoxy-2,4-diaminobenzene, octadecanoxy-2,4-diaminobenzene, dodecaneoxy-2,5-diaminobenzene, tetradecanoxy-2,5-diaminobenzene, Decanoxy-2,5-diaminobenzene, hexadecaneoxy-2,5-diaminobenzene, octadecaneoxy-2,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, 3, 5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestenyloxy-2,4-diaminobenzene, 3,5-diaminobenzoic acid cholestanyl, 5-diaminobenzoic acid cholestenyl, 3,5-diaminobenzoic acid ranostanyl, 3,6-bis (4-aminobenzoyloxy) cholestane, 3,6-bis (4-aminophenoxy) 4- (4 ' -trifluoromethoxybenzoyloxy) cyclohexyl (4 - ((aminophenyl) methyl) -3,5-diaminobenzoate, 4- (4'-trifluoromethylbenzoyloxy) cyclohexyl- Phenyl) -4-butylcyclohexane, 1,1-bis (4 - ((aminophenoxy) methyl) ), 4-heptylcyclohexane, 1,1-bis (4 - ((aminophenyl) methyl) phenyl) -4- (4-heptylcyclohexyl) cyclohexane, . The diamines having a pretilt component can be used singly or in combination of two or more.

The total amount of the diamines having a pretilt component is preferably 5 mol% or more, more preferably 10 mol% or more, based on the total diamine.

[Molecular Weight Regulator]

In synthesizing the polyamic acid, the endmodified polymer may be synthesized using a suitable molecular weight regulator together with the tetracarboxylic dianhydride and the diamine as described above. By using such a polymer having a terminal modification type, the coating property (printing property) of the liquid crystal aligning agent can be further improved without impairing the effect of the present invention.

Examples of the molecular weight regulator include acid anhydride, monoamine compound, monoisocyanate compound, and the like. Specific examples of the acid anhydrides include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride, and n-hexadecylsuccinic anhydride. ;

As the monoamine compound, for example, aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine and the like;

Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

The use ratio of the molecular weight modifier is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, based on 100 parts by weight of the total amount of tetracarboxylic acid dianhydride and diamine to be used.

<Synthesis of polyamic acid>

The ratio of the tetracarboxylic acid dianhydride and the diamine to be used in the synthesis reaction of the polyamic acid in the present invention is such that the ratio of the acid anhydride group of the tetracarboxylic acid dianhydride to the equivalent of one equivalent of the amino group of the diamine is 0.2 to 2 equivalents , More preferably 0.3 to 1.2 equivalents.

The synthesis reaction of the polyamic acid is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20 ° C to 150 ° C, more preferably 0 to 100 ° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

Examples of the organic solvent include aprotic polar solvents, phenol and derivatives thereof, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like.

Specific examples of these organic solvents include, but are not limited to, the aprotic polar solvents such as N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, Dimethylformamide, dimethylsulfoxide,? -Butyrolactone, tetramethylurea, hexamethylphosphoric triamide, compounds represented by the following formula (1), and the like;

As the phenol derivative, for example, m-cresol, xylenol, halogenated phenol and the like;

Examples of the alcohols include methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether and the like;

Examples of the ketone include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and the like;

As the ester, for example, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate and the like;

Examples of the ether include diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether, ethylene glycol dimethyl ether , Ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, Tetrahydrofuran and the like;

As the halogenated hydrocarbon, for example, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene and the like;

Examples of the hydrocarbon include hexane, heptane, octane, benzene, toluene, xylene, isoamyl propionate, isoamyl isobutylate, diisopentyl ether and the like.

Among these organic solvents, an aprotic polar solvent, at least one selected from the group consisting of phenol and its derivatives (the first group of organic solvents), or at least one selected from organic solvents of the first group, Ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (second group of organic solvents). In the latter case, the use ratio of the organic solvent of the second group is preferably 50% by weight or less, more preferably 40% by weight or less, relative to the total amount of the organic solvent of the first group and the organic solvent of the second group By weight, and more preferably 30% by weight or less.

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

In this way, a reaction solution obtained by dissolving polyamic acid can be obtained. The reaction solution may be directly supplied to the preparation of the liquid crystal aligning agent. Alternatively, the polyamic acid contained in the reaction solution may be isolated and then supplied to the preparation of the liquid crystal aligning agent, or after the isolated polyamic acid is purified, . When the polyamic acid is subjected to dehydration ring closure to form a polyimide, the reaction solution may be directly supplied to the dehydration ring-closing reaction. Alternatively, the polyamic acid contained in the reaction solution may be isolated and then subjected to dehydration ring- May be purified and then subjected to a dehydration ring-closing reaction. The polyamic acid can be isolated and purified by a known method.

<Synthesis of polyimide and polyimide>

The polyimide contained in the liquid crystal aligning agent of the present invention can be obtained by imidizing the polyamic acid synthesized as described above by dehydration ring closure.

The polyimide may be a complete imide cargo which is dehydrated and ring-closed with all of the arboric acid structure possessed by the polyamic acid which is the precursor thereof. The polyimide may be dehydrated and ring-closed only a part of the arboric acid structure to form a partial imide cargo . The imide ratio of the polyimide in the present invention is preferably 30% or more, more preferably 50 to 99%, and even more preferably 60 to 99%. The imidization rate is expressed as a percentage of the ratio of the number of imide ring structures to the sum of the number of amide structure and the number of imide ring structure of polyimide. Here, a part of the imide ring may be an isoimide ring.

The dehydration ring closure of the polyamic acid is preferably carried out by a method of heating the polyamic acid, or a method of dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to the solution, and optionally heating . Of these, the latter method is preferable.

In the method of adding the dehydrating agent and the dehydrating ring-closing catalyst to the solution of the polyamic acid, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride can be used as the dehydrating agent. The amount of the dehydrating agent to be used is preferably 0.01 to 20 mol based on 1 mol of the acid structure of the polyamic acid. As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, collidine, lutidine and triethylamine can be used. The amount of the dehydration ring-closing catalyst to be used is preferably 0.01 to 10 mol based on 1 mol of the dehydrating agent to be used. Examples of the organic solvent used in the dehydration ring-closure reaction include the organic solvents exemplified for use in the synthesis of polyamic acid. The reaction temperature of the dehydration ring-closing reaction is preferably 0 to 180 캜, more preferably 10 to 150 캜. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

In this manner, a reaction solution containing polyimide can be obtained. This reaction solution may be provided as it is in the preparation of a liquid crystal aligning agent, or may be supplied to the preparation of a liquid crystal aligning agent after removing the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution. Alternatively, after the polyimide is isolated, Or may be added to the preparation of a liquid crystal aligning agent after purification of the isolated polyimide. These purification operations can be carried out according to a known method.

&Lt; Solution viscosity of polymer &gt;

The polyamic acid and polyimide obtained as described above preferably have a solution viscosity of 10 to 800 mPa · s and a solution viscosity of 15 to 500 mPa · s Do. The solution viscosity (mPa · s) of the polymer is preferably in a good solvent (good solvent) of the polymer (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, -Imidazolidinone, N-ethyl-2-pyrrolidone, etc.) at 25 占 폚 using an E-type rotational viscometer.

· For antioxidant (b)

The liquid crystal aligning agent of the present invention contains an antioxidant (b) as an additive. The antioxidant (b) functions as a radical supplements or a peroxide decomposition releasing the peroxide radical or hydroperoxide generated by energy such as ultraviolet rays or heat. By containing such antioxidant (b) in the liquid crystal alignment film, when peroxydicarboxylic acid or hydroperoxide occurs in the liquid crystal alignment film or in the liquid crystal alignment film of the liquid crystal display element due to the prolonged use of the liquid crystal display element, And deterioration of the electrical characteristics of the liquid crystal display element due to oxycarbide or the like is suppressed.

As the antioxidant (b), for example, a compound having a hindered amine structure, a compound having a hindered phenol structure, a compound having an alkyl phosphate structure (phosphorus-based antioxidant), a compound having a thioether structure Antioxidants), mixtures thereof (blend-based antioxidants), and the like.

The antioxidant (b) to be used is preferably a compound having a hindered amine structure, a compound having a hindered phenol structure, or a mixture thereof (hereinafter also referred to as a specific antioxidant). When such a specific antioxidant is used, the electric characteristics of the liquid crystal display element after the long driving time of the liquid crystal display element can be improved compared to the case of using other antioxidant (for example, a phosphorus antioxidant or a sulfur-based antioxidant) It can be kept good. That is, the light resistance of the liquid crystal display element can be further improved.

Specifically, a compound represented by the following formula (d1) as a compound having a hindered amine structure and a compound represented by the following formula (d2) as a compound having a hindered phenol structure can be suitably used.

(In the formula (d1), R ⁴ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 13 carbon atoms, a 1,3- di-oxobutyl group; However, R ⁴ is, may even form a part of the molecular chain as a divalent group having from which one hydrogen atom has been removed the art R ^4; R ⁵ ~R ⁸ are, each independently having a carbon number of 1 to 6 alkyl group, 6 to 12 carbon atoms of the aryl group or an aralkyl group having a carbon number of 7-13 and; X ¹ is a single bond, an oxygen atom, a carbonyl _{group, ** - (CH 2) n} -O- (n is 1 to integer of 4) or ** - a CONH-, X ² ~X ⁵ are each independently a single bond, carbonyl group, ** - CH ₂ -CO-, or _{** - CH 2 -CH (OH)} - is; With the proviso that ** represents the bonding bond bonding with the piperidine ring;

(In the formula (d2), R ⁹ is a hydrocarbon group having 4 to 16 carbon atoms or a group containing at least any one of "-O-" and "-S-" between carbon-carbon bonds of the hydrocarbon group; R ¹⁰ is a hydrogen atom or a hydrocarbon group having 1 to 16 carbon atoms and a is an integer of 0 to 3, provided that when a is 2 or 3, plural R ¹⁰ independently have the above definition; Indicating a combined hand).

Examples of the alkyl group having 1 to 20 carbon atoms for R ⁴ in the formula (d1) include methyl, ethyl, propyl, butyl, pentyl, hexyl, An undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, and a nonadecyl group.

Examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a 3-fluorophenyl group, a 3-chlorophenyl group, a 4-chlorophenyl group, a 4-i-propylphenyl group, Methylphenyl group, a 4-pyridinyl group, a 2-phenyl-4-quinolinyl group, a 2- (4'- Norbornyl group and the like;

Examples of the aralkyl group having 7 to 13 carbon atoms include a benzyl group, a phenethyl group and the like; Respectively.

As the aralkyl group of R ⁵ ~R ⁸ having 1 to 6 carbon atoms alkyl group, an aryl group having a carbon number of 7-13 and having a carbon number of 6 to 12 of the, in the description of the R ^4, the alkyl group having 1 to 6 carbon atoms, having a carbon number of 6 to 12 An aryl group and an aralkyl group having 7 to 13 carbon atoms.

Examples of the group represented by "-X ¹ -R ⁴ " in the formula (d1) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, An acetyl group, a phenyl group, a benzyl group, a 1,3-dioxobutyl group, a 1, 3-dioxobutyl group, (2 ', 4', 5 ', 6', 6 ', 6', 6 ', 7', 8 ' 4-quinolinyl group, a group represented by the formula -CONH-Ph (wherein Ph represents a phenyl group, a 3-fluorophenyl group, a 3-chlorophenyl group, a 4-chlorophenyl group, -Butylphenyl group or a 3-chloro-4-methylphenyl group ").

R ⁴ may form part of a molecular chain as a divalent group obtained by removing one hydrogen atom of a carbon atom. In this case, as the divalent group represented by the "-X ¹ -R ⁴ ', in each of the examples in the description of the monovalent group represented by the group" -X ¹ -R ⁴ ", one of the hydrogen atoms having a carbon atom The dogs are removed.

Examples of the group represented by "-X ² -R ⁵ ", "-X ³ -R ⁶ ", "-X ⁴ -R ⁷ ", and "-X ⁵ -R ⁸ " in the formula (d1) A methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-butyl group, an i-butyl group, 2-phenylethyl group, 2-oxo-2- (3,4,5-trimethoxyphenyl) ethyl group and the like. Further, "-X ² -R ⁵ ", "-X ³ -R ⁶ ", "-X ⁴ -R ⁷ " and "-X ⁵ -R ⁸ " may be the same or different.

Examples of the hydrocarbon group having 4 to 16 carbon atoms for R ⁹ in the formula (d2) include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Specific examples of the aliphatic hydrocarbon group include those exemplified as the alkyl group having ⁴ to 16 carbon atoms in the description of R ⁴ above; As the alicyclic hydrocarbon group, for example, cyclopentyl group, cyclohexyl group, norbornyl group, isobonyl group, adamantyl group, tricyclodecanyl group and the like; Examples of the aromatic hydrocarbon group include a phenyl group, a fluorophenyl group, a chlorophenyl group, a benzyl group, a phenethyl group and the like; Respectively. R ⁹ may also be a monovalent group containing at least one of "-O-" and "-S-" between the carbon-carbon bonds of the above-mentioned hydrocarbon groups having 4 to 16 carbon atoms.

Preferable specific examples of R ⁹ include, for example, t-butyl, 1-methylpentadecyl, 1-ethylpentadecyl, octylthiomethyl, decylthiomethyl, dodecylthiomethyl and tetradecylthiomethyl groups.

Examples of the hydrocarbon group having 1 to 16 carbon atoms represented by R ¹⁰ include the groups exemplified in the description of R ⁹ in addition to the methyl group, ethyl group, n-propyl group, i-propyl group and the like.

The bonding position of R &lt; ¹⁰ &gt; is not particularly limited, but is preferably an ortho position with respect to the phenolic hydroxyl group or a para position relative to R &lt; ⁹ &gt;

Preferable specific examples of R ¹⁰ include, for example, methyl, ethyl, t-butyl, 1-methylpentadecyl and 1-ethylpentadecyl.

As the antioxidant (b), a commercially available product may be used. Specific examples of such a compound include commercially available products of compounds having an amine structure such as Adekastab LA-52, LA-57, LA-63, LA-68, LA-72, LA- (Manufactured by ADEKA), CHIMASSORB119, CHIMASSORB2020, CHIMASSORB944, TINUVIN622, TINUVIN123, TINUVIN144, TINUVIN765, TINUVIN770, TINUVIN111, TINUVIN783, TINUVIN791 (manufactured by ADEKA), LA- Manufactured by BASF Japan);

Examples of commercially available compounds having a phenolic structure include adecustable AO-20, copper AO-30, copper AO-40, copper AO-50, copper AO-60, copper AO-80, copper AO- IRGANOX 1050, IRGAOX 1076, IRGANOX 1135, IRGANOX 1135, IRGANOX 1330, IRGANOX 1726, IRGANOX 1425, IRGANOX 1520, IRGANOX 254, IRGANOX 259, IRGANOX 3114, IRGANOX 3710, IRGANOX 5057, IRGANOX 565, and IRGAMOD 295 (manufactured by BASF Japan);

PEP-8, copper PEP-36, HP-10, 2112 (manufactured by ADEKA), IRGAFOS 168, and GSY-P101 (manufactured by ADEKA) IRGAFOS 168, IRGAFOS 12, IRGAFOS 126, IRGAFOS 38, and IRGAFOS P-EPQ (manufactured by BASF Japan);

Examples of commercial products of the sulfur-based antioxidant include Adekustab AO-412, AO-503 (manufactured by ADEKA), IRGANOX PS 800, IRGANOX PS 802 (manufactured by BASF Japan);

As the commercial products of the blend-type antioxidant, for example, Adekstab A-611, A-612, A-613, AO-37, AO-15, AO- ), TINUVIN 111, TINUVIN 783, TINUVIN 791 (manufactured by BASF Japan); . The antioxidant (b) may be used alone or in combination of two or more.

The content of the antioxidant (b) is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 10 parts by weight, per 100 parts by weight of the polymer (a), from the viewpoint of both suppressing oxidation deterioration of the liquid crystal display element and improving printability Is preferably 0.01 to 5 parts by weight, particularly preferably 0.1 to 3 parts by weight.

· About solvent

The liquid crystal aligning agent of the present invention is constituted by dissolving the polymer (a) and the antioxidant (b) in a solvent. As such a solvent, the liquid crystal aligning agent of the present invention is preferably at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, And contains a kind of solvent (c). The solvent (c) has high solubility in polyamic acid and polyimide, and high boiling point. By using such a solvent (c), volatilization of the solvent from the printing machine can be suppressed during printing on the substrate of the liquid crystal aligning agent, and the polymer component and the antioxidant are hardly precipitated on the printing machine. As a result, Can be improved.

(In the formula (1), R ¹ and R ² are each independently a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or a monovalent group containing -O- between carbon-carbon bonds of the hydrocarbon group, R ¹ and R ² may combine with each other to form a ring structure; and R ³ is an alkyl group having 1 to 6 carbon atoms).

The hydrocarbon group having 1 to 6 carbon atoms in R ¹ and R ² in the formula (1) may be saturated or unsaturated. Also, R ¹ and R ² may include "-O-" between the carbon-carbon single bond of the hydrocarbon group having 1 to 6 carbon atoms. Specific examples of R ¹ and R ² include, for example, an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and groups containing "-O-" between carbon-carbon bonds of these groups have. In formula (1), R ¹ and R ² may be the same or different.

Examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, And practical training.

Examples of the alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group and the like; Examples of the aromatic hydrocarbon group include a phenyl group and the like; .

R ¹ and R ² may be bonded to each other to form a ring together with the nitrogen atom to which R ¹ and R ² bond. Examples of the ring formed by bonding R ¹ and R ² to each other include a pyrrolidine ring and a piperidine ring. In these rings, monovalent chain hydrocarbon groups such as a methyl group may be bonded.

R ¹ and R ² are preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group.

The alkyl group having 1 to 6 carbon atoms represented by R ³ may be linear or branched, and specifically includes the groups exemplified for the alkyl groups having 1 to 6 carbon atoms represented by R ¹ and R ² . Among them, those in which R ³ is an alkyl group having 1 to 4 carbon atoms can be preferably used.

Specific examples of the compound represented by the formula (1) include 3-methoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide, 3-hexyloxy- Isopropoxy-N-isopropyl-propionamide, and n-butoxy-N-isopropyl-propionamide. Among them, 3-methoxy-N, N-dimethylpropanamide and 3-butoxy-N, N-dimethylpropanamide can be preferably used.

As the solvent (c), the above-exemplified compounds may be used singly or in combination of two or more. Among them, 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropanamide, Amide, or a combination of two or more of them may be particularly preferably used.

From the viewpoint of suppressing the precipitation of the polymer (a) and the antioxidant (b) during printing and improving the printing property, the solvent (c) is used in an amount of not less than 5% by weight based on the total solvent contained in the liquid crystal aligning agent , More preferably 10 wt% or more. From the viewpoint of decreasing the residual amount of the solvent in the formed liquid crystal alignment film and improving the electrical characteristics, the upper limit of the content of the solvent (c) is preferably 90 By weight or less, more preferably 70% by weight or less, and further preferably 50% by weight or less.

As the solvent used for preparing the liquid crystal aligning agent of the present invention, other solvents than the above-mentioned solvent (c) may be used. Examples of other solvents include N-methyl-2-pyrrolidone,? -Butyrolactone,? -Butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, Methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n Propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether (DP M), diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate and the like. These may be used alone or in combination of two or more.

<Other components>

The liquid crystal aligning agent of the present invention contains the polymer (a), the antioxidant (b) and the solvent as described above, but may contain other components as necessary. Such other components include, for example, other polymers other than the specific polymer, a compound having at least one epoxy group in the molecule (hereinafter referred to as an &quot; epoxy group-containing compound &quot;), and a functional silane compound.

[Other Polymers]

The other polymer may be used for improving solution characteristics and electrical properties. Examples of such other polymers include polyamic acid esters, polyesters, polyamides, polysiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly (styrene-phenylmaleimide) have.

When the other polymer is added to the liquid crystal aligning agent, the blending ratio thereof is preferably 50% by weight or less, more preferably 0.1 to 40% by weight, further preferably 0.1 to 30% by weight based on the total amount of the polymer in the composition desirable.

[Epoxy group-containing compound]

The epoxy group-containing compound can be used for improving adhesion to the substrate surface in the liquid crystal alignment film. Examples of the epoxy group-containing compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether Diallyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylol propane triglycidyl ether, 2,2-dibromonopentyl glycol di N, N, N ', N'-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N, N-diglycidyl-benzylamine, N, N-diglycidylaminomethylcyclohexane, N-diglycidyl-cyclohexylamine, and the like. As other examples of the epoxy group-containing compound, an epoxy group-containing polyorganosiloxane described in International Publication No. 2009/096598 can also be used.

When these epoxy compounds are added to the liquid crystal aligning agent, the blending ratio thereof is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight, per 100 parts by weight of the total amount of the polymers contained in the liquid crystal aligning agent.

[Functional silane compound]

The functional silane compound can be used to improve the printability of the liquid crystal aligning agent. Examples of such a functional silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2 -Aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane Silane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N- Trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3 , 6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, methyl 9-trimethoxysilyl-3,6-diazononanoate, Benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl- N-phenyl-3-aminopropyltriethoxysilane, glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and the like.

When these functional silane compounds are added to the liquid crystal aligning agent, the blending ratio thereof is preferably 2 parts by weight or less, more preferably 0.02 to 0.2 parts by weight based on 100 parts by weight of the total of the polymers.

Other components include compounds having at least one oxetanyl group in the molecule (hereinafter referred to as &quot; oxetanyl group-containing compound &quot;), and the like. Specific examples of the oxetanyl group-containing compound include 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene (aroxoxetane OXT-121 (XDO) Bis (3-ethyloxetan-3-yl) methoxy] benzene (HQOX), di [2- (3-oxetanyl) butyl] ether (aroxoxetane OXT- And the like.

The solid concentration of the liquid crystal aligning agent of the present invention (the ratio of the total weight of the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent other than the solvent) is appropriately selected in consideration of viscosity, volatility, etc., 1 to 10% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the surface of the substrate as described later, and is preferably heated to form a coating film which becomes a liquid crystal alignment film or a liquid crystal alignment film. When the solid concentration is less than 1 wt% , The film thickness of this coating film becomes too small to obtain a good liquid crystal alignment film. On the other hand, when the solid concentration exceeds 10% by weight, the film thickness of the coating film becomes excessively large, so that a good liquid crystal alignment film can not be obtained, and further, the viscosity of the liquid crystal aligning agent increases and the coating property becomes poor.

A particularly preferable range of the solid concentration is different depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, in the case of the spinner method, the solid content concentration is particularly preferably in the range of 1.5 to 4.5 wt%. In the case of the printing method, it is particularly preferable to set the solid concentration in the range of 3 to 9% by weight and the solution viscosity in the range of 12 to 50 mPa · s accordingly. In the case of the inkjet method, it is particularly preferable that the solid concentration is in the range of 1 to 5 wt%, and the solution viscosity is in the range of 3 to 15 mPa · s.

The temperature for preparing the liquid crystal aligning agent of the present invention is preferably 10 to 50 占 폚, more preferably 20 to 30 占 폚.

<Liquid Crystal Alignment Film and Liquid Crystal Display Device>

The liquid crystal alignment film of the present invention is formed by the liquid crystal aligning agent prepared as described above. Further, the liquid crystal display element of the present invention comprises a liquid crystal alignment film formed using the liquid crystal aligning agent of the present invention. The liquid crystal display of the present invention may be applied to an operation mode of a horizontal alignment type such as an IPS, TN, STN, or FFS type, or may be applied to a vertical alignment type operation mode such as VA.

Hereinafter, a method of manufacturing the liquid crystal display element of the present invention will be described, and a method of manufacturing the liquid crystal alignment film of the present invention will be described. The liquid crystal display element of the present invention can be produced, for example, by the following steps (1) to (3). Process (1) differs from substrate to be used in accordance with a desired operation mode. Steps (2) and (3) are common to each operation mode.

[Process (1): Formation of coating film]

First, the liquid crystal aligning agent of the present invention is coated on a substrate, and then a coated film is formed on the substrate by heating the coated surface.

(1-1) In the case of producing a TN type, STN type or VA type liquid crystal display device, two substrates on which a patterned transparent conductive film is formed are paired, and on the respective transparent conductive film forming surfaces, (Preferably preheating (prebaking) and firing (post baking) by applying the liquid crystal aligning agent of the liquid crystal aligning agent, preferably by an offset printing method, a spin coating method, a roll coater method or an inkjet printing method, ) To form a coating film. Examples of the substrate include glass such as float glass and soda glass; A transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, and poly (alicyclic olefin) can be used. As the transparent conductive film to be formed on one surface of the substrate, an ITO film made of NESA film (a registered trademark of PPG Corporation of the US) or indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) made of tin oxide (SnO ₂ ) . In order to obtain a patterned transparent conductive film, for example, a method of forming a pattern by photoetching after forming a pattern-free transparent conductive film, a method of using a mask having a desired pattern for forming a transparent conductive film, and the like . When applying the liquid crystal aligning agent, a functional silane compound, a functional titanium compound or the like is preferably added to the surface of the substrate on which the coating film is to be formed, in order to improve the adhesion between the substrate surface and the transparent conductive film and the coating film The pre-treatment for pre-coating may be carried out.

After application of the liquid crystal aligning agent, preheating (prebaking) is preferably performed for the purpose of preventing the flow of the liquid of the applied aligning agent or the like. The prebaking temperature is preferably 30 to 200 캜, more preferably 40 to 150 캜, and particularly preferably 40 to 100 캜. The prebaking time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Thereafter, the solvent is completely removed, and a baking (post-baking) step is carried out for the purpose of thermally modifying the acid structure present in the polymer as required. The firing (post-baking) temperature is preferably 80 to 300 占 폚, more preferably 120 to 250 占 폚. The post baking time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The film thickness of the film thus formed is preferably 0.001 to 1 占 퐉, and more preferably 0.005 to 0.5 占 퐉.

(1-2) In the case of producing an IPS or FSS type liquid crystal display element, the electrode formation surface of the substrate on which the electrode composed of the transparent conductive film or the metal film patterned in the comb shape is formed, The liquid crystal aligning agent of the present invention is applied to one side of the substrate, and then each coated side is heated to form a coated film. The material, the coating method, the heating conditions after coating, the method of patterning the transparent conductive film or the metal film, the pretreatment of the substrate, and the preferable film thickness of the coating film to be formed are the same as those in the above (1-1) . As the metal film, for example, a film made of a metal such as chromium can be used.

In any one of (1-1) and (1-2), a coating film to be an alignment film is formed by applying a liquid crystal aligning agent on a substrate and then removing the organic solvent. When the polymer contained in the liquid crystal aligning agent of the present invention is a polyamic acid or an imidized polymer having an imidazole ring structure and an arboric acid structure, the dehydration ring-closure reaction is further advanced by heating after forming the film, Or may be a coated film.

[Process (2): rubbing treatment]

In the case of producing a TN type, STN type, IPS type or FFS type liquid crystal display device, the coating film formed in the above step (1) is coated with a cloth made of fibers such as nylon, rayon, Rub rubbing treatment is performed. Accordingly, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film. On the other hand, in the case of manufacturing a VA type liquid crystal display device, the coating film formed in the above step (1) can be directly used as a liquid crystal alignment film, but the coating film may be rubbed.

The liquid crystal alignment layer may be formed by irradiating a part of the liquid crystal alignment layer with ultraviolet rays to change the pretilt angle of a part of the liquid crystal alignment layer or by forming a resist film on a part of the surface of the liquid crystal alignment layer, And then the resist film is removed so that the liquid crystal alignment film has a different liquid crystal aligning ability for each region. In this case, it is possible to improve the clock characteristic of the obtained liquid crystal display element.

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

Two substrates on which the liquid crystal alignment film is formed as described above are prepared, and the liquid crystal is arranged between the two substrates arranged opposite to each other to manufacture a liquid crystal cell. Here, when the coating film is subjected to the rubbing treatment, the two substrates are opposed to each other such that the rubbing directions of the coating films are at a predetermined angle, for example, orthogonal or anti-parallel to each other.

For example, the following two methods can be used to manufacture the liquid crystal cell.

The first method is a conventionally known method. First, two substrates are opposed to each other with a gap (cell gap) interposed therebetween so that the respective liquid crystal alignment films face each other, and the peripheral portions of the two substrates are bonded to each other using a sealant. After the liquid crystal is injected and filled in the cell gap, the injection hole is sealed to manufacture the liquid crystal cell.

The second method is a method called ODF (One Drop Fill) method. For example, an ultraviolet curable sealant is applied to a predetermined place on one of the two substrates on which the liquid crystal alignment film is formed, and liquid crystal is further dropped onto a predetermined number of places on the liquid crystal alignment film surface, The liquid crystal cell can be manufactured by spreading the liquid crystal on the entire surface of the substrate and then irradiating the entire surface of the substrate with ultraviolet light to cure the sealant.

In either case, the liquid crystal cell manufactured as described above is further heated to a temperature at which the liquid crystal used is isotropic, and then gradually cooled to room temperature to remove the flow alignment at the time of filling the liquid crystal desirable.

The liquid crystal display element of the present invention can be obtained by bonding a polarizing plate to the outer surface of the liquid crystal cell.

As the sealing agent, for example, an epoxy resin containing a curing agent and an aluminum oxide sphere as a spacer can be used.

Examples of the liquid crystal include nematic liquid crystals and smectic liquid crystals. Of these, nematic liquid crystals are preferable, and examples thereof include a cypher base liquid crystal, an agar watch liquid crystal, a biphenyl liquid crystal, a phenyl cyclohexane liquid crystal, , Terphenyl-based liquid crystals, biphenylcyclohexane-based liquid crystals, pyrimidine-based liquid crystals, dioxane-based liquid crystals, bicyclooctane-based liquid crystals, quaternary type liquid crystals and the like. Further, to these liquid crystals, for example, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonanoate and cholesteryl carbonate; Chiral agents such as those sold under the trade names "C-15" and "CB-15" (Merck); p-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate, or the like may be added and used.

As the polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing plate in which a polarizing film called "H film" in which iodine is absorbed while polyvinyl alcohol is oriented in a stretched polyvinyl alcohol is sandwiched between cellulose acetate protective films or a polarizing plate comprising H film itself .

The liquid crystal display device of the present invention can be effectively applied to various devices and can be applied to various devices such as a clock, a portable game, a word processor, a notebook computer, a car navigation system, a camcorder, a PDA, , Various monitors, liquid crystal televisions, and information displays.

(Example)

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

The solution viscosity of each polymer solution and the imidization rate of polyimide in the synthesis examples were measured by the following methods.

[Solution viscosity of polymer solution]

The solution viscosity [mPa 占 퐏] of the polymer solution was measured at 25 占 폚 using an E-type rotational viscometer for a solution prepared by using a predetermined solvent and having a polymer concentration of 10% by weight.

[Imidization Rate of Polyimide]

The polyimide solution was poured into pure water, and the obtained precipitate was sufficiently dried under reduced pressure at room temperature. The precipitate was dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference material. From the obtained ¹ H-NMR spectrum, the imidization ratio [%] was determined by the following equation (1).

Imidization rate [%] = ((1-A ¹ ) / (A ² × α)) × 100 (One)

(In the formula (1), A ¹ is the peak area derived from the proton of the NH group near the chemical shift of 10 ppm, A ² is the peak area derived from the other proton, and? Is the peak area derived from the proton The ratio of the number of other protons to one proton in the NH group).

&Lt; Synthesis of Polymer (a) &gt;

Polymerization Example 1: Synthesis of polyimide (PI-1)

22.4 g (0.1 mole) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride (TCA) as tetracarboxylic acid dianhydride, 2.2 g (0.02 mole) of p-phenylenediamine (PDA) 7.6 g (0.05 mol) of diaminobenzoic acid (DAB), 10.5 g (0.02 mol) of 3,5-diaminobenzoic acid cholestanyl (HCDA) and 4.9 g of cholestanyloxy-2,4-diaminobenzene (0.01 mol) was dissolved in 190 g of N-methyl-2-pyrrolidone (NMP), and the reaction was carried out at 60 DEG C for 6 hours to obtain a solution containing 20 wt% of polyamic acid. The solution viscosity of the obtained polyamic acid solution measured by adding NMP to a solution having a polyamic acid concentration of 10 wt% was 88 mPa · s.

Next, 442 g of NMP was added to the obtained polyamic acid solution, 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and the dehydration ring-closure reaction was carried out at 110 DEG C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with a solvent by a new NMP (pyridine and anhydrous acetic acid used in the dehydration ring closure reaction were removed out of the system by this operation; 1) was obtained in an amount of 26% by weight. A small amount of the obtained polyimide solution was collected, and the solution viscosity was measured as a solution having a polyimide concentration of 10% by weight by adding NMP, and the solution viscosity was 55 mPa · s.

[Polymerization Example 2: Synthesis of polyimide (PI-2)] [

(0.04 mole) of PDA as a diamine, 3.1 g (0.02 mole) of DAB, 5.2 g (0.01 mole) of HCDA and 14.9 g (0.03 mole) of HCODA as a diamine were added to 200 g , And the reaction was carried out at 60 DEG C for 6 hours to obtain a solution containing 20 wt% of polyamic acid. The solution viscosity of the obtained polyamic acid solution measured by adding NMP to a solution having a polyamic acid concentration of 10 wt% was 60 mPa · s.

Subsequently, 464 g of NMP was added to the obtained polyamic acid solution, 7.9 g of pyridine and 10.3 g of acetic anhydride were added, and the dehydration ring-closure reaction was carried out at 110 DEG C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with a fresh NMP solvent to obtain a solution containing 26% by weight of a polyimide (PI-2) having an imidization rate of about 51%. A small amount of the obtained polyimide solution was collected, and the solution viscosity was measured as a solution having a polyimide concentration of 10% by weight by adding NMP. The viscosity of the solution was 39 mPa · s.

[Polymerization Example 3: Synthesis of polyimide (PI-3)] [

24.9 g (0.10 mol) of 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4, 6: 8-2 anhydride (BODA) as tetracarboxylic acid dianhydride, 2.2 g (0.02 mole) of DAB, 7.6 g (0.05 mole) of DAB, 10.4 g (0.02 mole) of HCDA and 4.9 g (0.01 mole) of HCODA were dissolved in 200 g of NMP and reacted at 60 ° C for 6 hours. Was obtained. The solution viscosity of the obtained polyamic acid solution measured by adding NMP to a solution having a polyamic acid concentration of 10 wt% was 70 mPa · s.

Subsequently, 464 g of NMP was added to the resulting polyamic acid solution, 11.8 g of pyridine and 15.3 g of acetic anhydride were added, and the dehydration ring-closure reaction was carried out at 110 DEG C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with a fresh NMP solvent to obtain a solution containing 26% by weight of polyimide (PI-3) having an imidization rate of about 63%. A small amount of the obtained polyimide solution was collected, and the solution viscosity was measured as a solution having a polyimide concentration of 10% by weight by adding NMP, and the solution viscosity was 53 mPa · s.

[Polymerization Example 4: Synthesis of polyimide (PI-4)] [

(0.10 mole) of TCA as tetracarboxylic dianhydride, 6.5 g (0.06 mole) of PDA as diamine, 4.0 g (0.02 mole) of 4,4'-diaminodiphenylmethane (DDM) and 5.2 g ) And 4.9 g (0.01 mole) of HCODA were dissolved in 172 g of NMP, and the reaction was carried out at 60 DEG C for 6 hours to obtain a solution containing 20 wt% of polyamic acid. The solution viscosity of the obtained polyamic acid solution measured by adding NMP to a solution having a polyamic acid concentration of 10 wt% was 101 mPa · s.

Subsequently, 400 g of NMP was added to the obtained polyamic acid solution, 10.3 g of pyridine and 13.3 g of acetic anhydride were added, and the dehydration ring-closure reaction was carried out at 110 DEG C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with a fresh NMP solvent to obtain a solution containing 26% by weight of a polyimide (PI-4) having an imidization rate of about 55%. A small amount of the obtained polyimide solution was collected, and the solution viscosity was measured as a solution having a polyimide concentration of 10% by weight by adding NMP, and the solution viscosity was 65 mPa · s.

[Polymerization Example 5: Synthesis of polyimide (PI-5)] [

A polyamic acid solution was obtained in the same manner as in Polymerization Example 1 except that 1,3-dimethyl-2-imidazolidinone (DMI) was used instead of NMP. The solution viscosity of the obtained polyamic acid solution measured by adding DMI to a solution having a polyamic acid concentration of 10 wt% was 90 mPa · s.

Then, polyimide was synthesized using the obtained polyamic acid solution. Synthesis was carried out in the same manner as in Polymerization Example 1 except that DMI was used instead of NMP to obtain a solution containing 26% by weight of a polyimide (PI-5) having an imidization rate of about 66%. A small amount of the obtained polyimide solution was collected and DMI was added thereto to obtain a solution having a polyimide concentration of 10% by weight, and the solution viscosity was 56 mPa · s.

[Polymerization Example 6: Synthesis of polyimide (PI-6)] [

A polyamic acid solution was obtained in the same manner as in Polymerization Example 2 except that N-ethyl-2-pyrrolidone (NEP) was used instead of NMP. The solution viscosity of the obtained polyamic acid solution measured by adding NEP to a solution having a polyamic acid concentration of 10 wt% was 59 mPa · s.

Then, polyimide was synthesized using the obtained polyamic acid solution. Synthesis was carried out in the same manner as in Polymerization Example 2 except that NEP was used instead of NMP, whereby a solution containing 26% by weight of polyimide (PI-6) having an imidization rate of about 49% was obtained. A small amount of the obtained polyimide solution was collected, and NEP was added thereto to obtain a solution having a polyimide concentration of 10 wt%, and the solution viscosity was 38 mPa · s.

&Lt; Preparation of liquid crystal aligning agent &

[Example 1]

3 parts by weight of IRGANOX 1010 (manufactured by BASF Japan K.K.) as antioxidant to 100 parts by weight of polyimide (PI-1) was added to a solution containing 100 parts by weight of synthesized polyimide (PI-1) The solvent composition was NMP: BC: DMI = 30: 50: 20 (weight ratio), and the solid content (mass ratio) of ethylene glycol- And a concentration of 6.5 wt%. This solution was filtered using a filter having a pore size of 1 탆 to prepare a liquid crystal aligning agent.

[Examples 2 to 14, Comparative Examples 1 to 7]

A liquid crystal aligning agent was prepared in the same manner as in Example 1 except that the polyimide, antioxidant and solvent composition used were changed as shown in the following Table 1, respectively.

&Lt; Evaluation of printability &gt;

The printability of each of the liquid crystal aligning agents prepared above was evaluated. The evaluation was carried out as follows. First, a liquid crystal aligning agent to anilox roll was applied to each of the prepared liquid crystal aligning agents by using a liquid crystal alignment film printing machine (Nippon Shinyu Satsuki Sangyo Co., Ltd., Angstromer type "S40L-532" Was applied on the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film under the condition of 20 drops reciprocating (about 0.2 g). The application to the substrate was carried out 20 times while using a new substrate at intervals of one minute.

Subsequently, a liquid crystal aligning agent was dispensed (one-way) on the anilox roll at intervals of one minute, and an operation of bringing the anilox roll and the printing plate into contact with each other (hereinafter referred to as idle operation) was performed 10 times in total , And printing on a glass substrate is not performed). Here, this coarse operation is not performed in the normal manufacturing process of the liquid crystal display element but is an operation performed so that the printing of the liquid crystal aligning agent onto the substrate is intentionally carried out under severe conditions.

After ten times of operation, the printing was performed using a glass substrate. In this printing, five substrates were put at intervals of 30 seconds after the ball operation, each substrate after applying the liquid crystal aligning agent was heated (prebaked) at 80 DEG C for 1 minute to remove the solvent, (Post baking) for a minute to form a coating film having a thickness of about 80 nm. The printability was evaluated by observing the pattern edge portion (outer peripheral portion of the print pattern) of this coating film with a microscope having a magnification of 20 times. In the evaluation, precipitates were observed from the first printing after the blank printing to a superior (O) when no precipitate (considered to be polyimide and antioxidant) was observed, and the first printing after the printing operation, (?) When no precipitate was observed during the execution, and the case where the precipitate was observed even after repeating this printing five times was regarded as poor (X). The evaluation results are shown in Table 1 below. In addition, in a liquid crystal aligning agent having a good printability, it was experimentally found that the precipitate was quantified (lost) while the substrate was continuously injected.

The printability of the liquid crystal aligning agent was evaluated by carrying out the same operation as above except that the number of times of the open operation was changed 15 times, 20 times, and 25 times. The evaluation results are shown in Table 1 below.

&Lt; Production of liquid crystal display element &

[Production Example 1]

The liquid crystal aligning agent of Example 1 prepared above was applied to a transparent electrode surface of a glass substrate with a transparent electrode made of ITO film having a thickness of 1 mm by a spinner and prebaked on a hot plate at 80 DEG C for 1 minute. Subsequently, the substrate after pre-baking was post-baked at 210 캜 for 30 minutes. Thus, a liquid crystal alignment film having a film thickness of about 80 nm was formed. This operation was repeated to obtain a pair of substrates (two substrates) each having a liquid crystal alignment film. Next, in one of the pair of substrates, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 占 퐉 was applied to the outer edge of the surface having the liquid crystal alignment film, and then the liquid crystal alignment film surface was superimposed and pressed against each other, . Subsequently, a nematic liquid crystal (MLC-6608, manufactured by Merck Ltd.) was filled between the pair of substrates from the liquid crystal injection port, and then a liquid crystal injection hole was sealed with an acrylic-based photo-curable adhesive to manufacture a liquid crystal cell.

[Production Examples 2 to 14, Comparative Production Examples 1 to 7]

Liquid crystal cells were prepared in the same manner as in Production Example 1, except that the liquid crystal aligning agent used was changed to those of Examples 2 to 14 and Comparative Examples 1 to 7.

&Lt; Evaluation of light resistance &

For each liquid crystal cell prepared above, a voltage of 5 V was applied at 70 캜 for an application time of 60 microseconds and a span of 167 milliseconds, and the voltage maintenance ratio after 167 ms after the application was released was measured by VHR-1 manufactured by Toyotec Respectively. This value was set as the initial voltage holding ratio VHR1 [%]. Subsequently, the liquid crystal cell after the VHR1 measurement was irradiated with light for 650 hours using a weather meter having a carbon arc as a light source. The voltage holding ratio of the liquid crystal cell after light irradiation was measured by the same method as described above. This value was set as the voltage holding ratio VHR2 [%] after light irradiation. The decrease amount? VHR [%] of the voltage holding ratio before and after light irradiation was obtained from the following formula (2), and the light resistance was evaluated by? VHR. The results are shown in Table 1 below. The smaller the? VHR, the better the light resistance.

 ? VHR [%] = VHR1-VHR2 ... (2)

The symbol of the solvent composition and the symbol of the antioxidant in Table 1 have the following meanings respectively.

a: N-methyl-2-pyrrolidone (NMP)

b: Ethylene glycol-mono-n-butyl ether (BC)

c:? -butyrolactone (GBL)

d: 1,3-dimethyl-2-imidazolidinone (DMI)

e: N-ethyl-2-pyrrolidone (NEP)

f: 3-Methoxy-N, N-dimethylpropanamide

g: 3-Butoxy-N, N-dimethylpropanamide

F-1: IRGANOX1010 (phenolic antioxidant)

F-2: Adhesive LA-72 (amine antioxidant)

F-3: TINUVIN 622 (amine antioxidant)

F-4: IRGAFOS12 (phosphorus antioxidant)

F-5: IRGANOX PS 800 (sulfur antioxidant)

F-6: Adhesive AO-40 (phenolic antioxidant)

As shown in Table 1, all of the liquid crystal aligning agents of the Examples were good in light fastness of the liquid crystal display element. Among them, in the case of using a hindered amine-based or hindered phenol-based antioxidant as the antioxidant (Examples 1 to 4, 6 and 8 to 14), the degradation amount of the voltage holding ratio before and after the long- To 3.1%, and the light resistance was particularly good.

With respect to the printability, in the liquid crystal aligning agent of the examples, no precipitate was observed from the first time in the main printing after 10 times of the operation. In addition, when the number of times of the blank operation was increased by 20 times and 25 times, the precipitates were observed during the first printing of this printing, but the precipitates disappeared during the fifth printing. From these viewpoints, it was found that the liquid crystal aligning agent of the Examples hardly generates precipitates during printing, and has good printability.

On the other hand, in the comparative examples (Comparative Examples 1, 2 and 5) in which the antioxidant was not included, although the printability was good, the amount of decrease in the voltage holding ratio due to the irradiation of light for a long time was as large as 9.3 to 12.3% The light resistance was not so good. In addition, in the case of containing the antioxidant but not containing the solvent (c) (Comparative Examples 3, 4, 6 and 7), precipitates were observed in the main printing after 10 times of operation, When 15 circuits were increased, precipitates were observed in all of the 5 main prints, and the printability was not so good.

Claims (6)

(A) at least one polymer (a) selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine and a polyimide obtained by dehydrocondensing the polyamic acid, and
B) at least one antioxidant (b) selected from the group consisting of a compound represented by the following formula (d1) and a compound represented by the following formula (d2)
C) at least one kind of solvent (c) selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone and compounds represented by the following formula (1)
&Lt; / RTI &gt;
The content of the antioxidant (b) is 0.01 to 3 parts by weight based on 100 parts by weight of the polymer (a)

(In the formula (d1), R ⁴ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 13 carbon atoms, a 1,3- di-oxobutyl group; However, R ⁴ is, may even form a part of the molecular chain as a divalent group having from which one hydrogen atom has been removed the art R ^4; R ⁵ ~R ⁸ are, each independently having a carbon number of 1 to 6 alkyl group, 6 to 12 carbon atoms of the aryl group or an aralkyl group having a carbon number of 7-13 and; X ¹ is a single bond, an oxygen atom, a carbonyl _{group, ** - (CH 2) n} -O- (n is 1 to integer of 4) or ** - a CONH-, X ² ~X ⁵ are each independently a single bond, carbonyl group, ** - CH ₂ -CO-, or _{** - CH 2 -CH (OH)} - is; With the proviso that ** represents the bonding bond bonding with the piperidine ring;

(Formula (d2) of, R ⁹ is a hydrocarbon group, or a carbon in the art hydrocarbon group having a carbon number of 4-16-carbon bond between the group which comprises at least one of -O- and -S-, and; R ¹⁰ is hydrogen Atom or a hydrocarbon group having 1 to 16 carbon atoms, and a is an integer of 0 to 3, provided that when a is 2 or 3, plural R ¹⁰ independently have the above definition; ;

(In the formula (1), R ¹ and R ² are each independently a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or a monovalent group containing -O- between carbon-carbon bonds of the hydrocarbon group, R ¹ and R ² may combine with each other to form a ring structure; and R ³ is an alkyl group having 1 to 6 carbon atoms). The method according to claim 1,
Wherein the content of the solvent (c) is 5 wt% or more of the total solvent. The method according to claim 1,
Wherein the polymer (a) is at least one selected from the group consisting of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane- 4,6: 8-2 anhydride, and the liquid crystal aligning agent is synthesized by using a compound containing at least one of 4,6: 8-2 anhydride. delete A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of claims 1 to 3. A liquid crystal display element comprising the liquid crystal alignment film according to claim 5.