KR101923080B1 - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display device - Google Patents

Abstract

A liquid crystal aligning agent excellent in printability is provided.
(A) a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine containing a diamine compound (a1) having at least one carboxyl group in the molecule, and a polyimide obtained by dehydrocondensing the polyamic acid (B) at least one kind of polymer selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone and compounds represented by the following formula At least one kind of solvent (B) is contained in the liquid crystal aligning agent.

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 which is less likely to precipitate a polymer component and has excellent printability (particularly long time printing property) To a liquid crystal alignment film and a liquid crystal display device to be manufactured.

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.

Recently, 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, display devices such as mobile phones and smart phones as in the past. On the other hand, depending on the use of the liquid crystal display element, the liquid crystal display element may be used under conditions more severe than conventional ones in terms of luminance and driving time. In this background, as a liquid crystal display element, in recent years, it has been further demanded that the display quality is low even when the display quality is high and continuous driving is performed for a long time, and liquid crystal aligning agents for obtaining such liquid crystal display elements are various (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

In order to improve the display quality of the liquid crystal display element, for example, the imidization ratio of the polyimide in the liquid crystal alignment film may be increased to improve the electrical characteristics, or the liquid crystal alignment component (pretilt component) may be introduced into the polyimide, It is conceivable to improve the performance of the apparatus. However, when these are carried out, the solubility of the polymer is lowered, the cohesiveness of the polymer is easily increased, and, due to this, there is a problem that printing unevenness occurs when the liquid crystal aligning agent is applied on the substrate, There is a case where the printing property is deteriorated due to precipitation or the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its main object to provide a liquid crystal aligning agent having excellent printability, and a liquid crystal alignment film and a liquid crystal display element manufactured using the liquid crystal aligning agent.

DISCLOSURE OF THE INVENTION The present inventors have intensively studied in order to achieve the above-described problems of the prior art. As a result, they have found that not only a polymer obtained by the reaction of a specific diamine and a tetracarboxylic acid dianhydride is used as a polymer component of a liquid crystal aligning agent, And then dissolved in a specific solvent to prepare a liquid crystal aligning agent. Thus, the present inventors have completed the present invention. Specifically, according to the present invention, the following liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element are provided.

According to the present invention, there is provided a polyamic acid composition comprising: (A) a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine containing a diamine compound (a1) having at least one carboxyl group in the molecule and a polyimide obtained by dehydrocondensing the polyamic acid (B) at least one polymer selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone and compounds represented by the following formula (B) at least one kind of solvent (B).

(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 liquid crystal aligning agent of the present invention contains the above polymer (A) as a polymer component and contains the above-mentioned solvent (B) as a solvent, whereby the coating property to the substrate is good, and even when printing on the substrate is performed for a long time The precipitation of the polymer is hardly caused and the printing property for a long time is excellent.

In the present invention, in order to further suppress precipitation of the polymer, it is preferable that the content of the solvent (B) is 10% by weight or more of the whole solvent. This makes it possible to improve the applicability to the substrate and the printing property for a long time. Examples of the tetracarboxylic acid dianhydride in the polymer (A) include 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane- 2: 4,6: 8-2 anhydride, can be suitably used.

In another embodiment of the present invention, the polymer (A) is at least one selected from the group consisting of 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl- -Amine and 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-inden-6-amine.

In the manufacturing process of the liquid crystal display element, the substrate may be left untouched (left alone) after formation of the liquid crystal alignment film by mechanical trouble or tact adjustment. At that time, since moisture in the air is adsorbed or absorbed by the liquid crystal alignment film, the electric characteristics of the liquid crystal display device manufactured using the substrate may be deteriorated and display unevenness may be caused. In this regard, in the present embodiment, examples of the diamine used for synthesizing the polymer include 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-inden-6-amine in combination with the diamine compound (a1) The electric characteristics of the liquid crystal display element can be maintained well (even when the substrate is left in a state in which the liquid crystal display element is formed).

The liquid crystal aligning agent of the present invention preferably contains, as a solvent, a dipropylene glycol monomethyl ether in addition to the above-mentioned solvent (B). By using the above-mentioned solvent (B) and dipropylene glycol monomethyl ether in combination, the printing property for a long time can be further improved.

According to the present invention, there is also provided 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. Since the liquid crystal alignment film of the present invention is formed by using the liquid crystal aligning agent described above, the polymer is hardly precipitated and the film quality is good even when printing is performed for a long time. In addition, when a liquid crystal display element is manufactured using such a liquid crystal alignment film, printing defects can be reduced in the manufacturing process, and as a result, the yield can be improved.

(Mode for carrying out the invention)

The liquid crystal aligning agent of the present invention contains at least one polymer selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine and a polyimide obtained by dehydrocondylating the polyamic acid, . Hereinafter, the liquid crystal aligning agent of the present invention will be described in detail.

<Polyamic acid>

[Tetracarboxylic acid dianhydride]

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

As the tetracarboxylic acid dianhydride used for synthesizing polyamic acid, those containing alicyclic tetracarboxylic dianhydride are preferable from the viewpoints of transparency and solubility in a solvent, and among them, 2,3, 5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) 3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) 2,3,4] octane-2, 4,6, 8-2 anhydride and 1,2,3,4-tetrahydrocarbazole- Cyclobutanetetracarboxylic acid dianhydride, and 3,4-cyclobutanetetracarboxylic acid dianhydride. Among them, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 2,3,5-tricarboxycyclopentyl acetic acid dianhydride are preferable in view of good printing property. 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-2 To include at least one of the water is preferred.

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. Is more preferable.

[Diamine]

As the diamine used for synthesizing the polyamic acid in the present invention, at least a diamine compound (a1) having at least one carboxyl group in the molecule is used. By using such compound (a1), the solubility of the polymer component (polyamic acid or polyimide) contained in the liquid crystal aligning agent in a solvent can be increased. In particular, solubility in a solvent containing the solvent (B) shown below is good, and the combination with the solvent can suitably improve the printability.

[Diamine compound (a1)]

The structure of the diamine compound (a1) is not limited as long as it has a carboxyl group, and may be any of an aliphatic diamine, an alicyclic diamine, an aromatic diamine, and a diaminoorganosiloxane. As the diamine compound (a1), an aromatic diamine is preferable, and in particular, a carboxyl group is bonded to an aromatic ring having an aromatic diamine.

The number of carboxyl groups in the molecule of the diamine compound (a1) is preferably 1 to 4, more preferably 1 or 2.

Examples of the preferable diamine compound (a1) include a compound represented by the following formula (a1-1) or a compound represented by the following formula (a1-2).

(Wherein X is a single bond, an oxygen atom or an alkanediyl group having 1 to 3 carbon atoms, m and n are each independently an integer of 1 or 2, and s and t are each independently 0 to 2 A hydrogen atom bonded to the carbon atom of the benzene ring may be substituted with an alkyl group having 1 to 5 carbon atoms).

Specific examples of the diamine compound (a1) include compounds represented by the following formulas (a1-1-1) to (a1-1-3), the following formulas (a1-2-1) to (a1-2-5) , And the like.

The proportion of the diamine compound (a1) is preferably 5 mol% or more, more preferably 10 to 80 mol%, more preferably 10 to 80 mol%, based on the total amount of the diamine used in the synthesis of the polyamic acid, from the viewpoint of enhancing solubility in the solvent of the polyamic acid , More preferably from 10 to 50 mol%.

As the diamine for synthesizing the polyamic acid, only the above-mentioned diamine compound (a1) may be used alone, but other diamines may be used together with the diamine compound (a1).

Examples of other diamines usable herein include aliphatic diamines other than the diamine compound (a1), alicyclic diamines, aromatic diamines, diaminoorganosiloxanes, and the like. Specific examples thereof 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-1H-inden-6-amine, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3,5-diamino Benzene, cholestanyloxy-2,4-diaminobenzene, cholestenyloxy-2,4-diaminobenzene, 3,5-diaminobenzoic acid cholestanyl, 3,5-diaminobenzoic acid cholestenyl, (4-aminobenzoyloxy) cholestane, 3,6-bis (4-aminophenoxy) cholestane, 4- (4'-trifluoromethyl) Diaminobenzoate, 4- (4'-trifluoromethylbenzoyloxy) cyclohexyl-3,5-diaminobenzoate, 1,1-bis (4- (Aminophenyl) methyl) phenyl) -4-butyl 4-heptylcyclohexane, 1,1-bis (4 - ((aminophenoxy) methyl) phenyl) -4-heptylcyclohexane, (4-heptylcyclohexyl) cyclohexane, 2,4-diamino-N, N-diallylaniline, 4-amino Benzylamine, 3-aminobenzylamine, and a compound represented by 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. The two amino groups in the diaminophenyl group are preferably in the 2,4-position or the 3,5-position relative to the group &quot; ^{XI &} quot ;.

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).

In order to synthesize the polyamic acid, other diamines such as 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-inden-5- Phenyl) -2,3-dihydro-1,3,3-trimethyl-1H-inden-6-amine. By using these other diamines in combination with the compound (a1), the resistance to neglect can be improved. The content thereof is preferably 5 mol% or more, more preferably 10 to 50 mol%, based on the total amount of the diamines used.

When synthesizing a polyamic acid contained in a liquid crystal aligning agent for a vertical alignment type, those having a pretilt component as the other 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, Diaminobenzene, 3,5-diaminobenzoic acid cholestanyl, 3,5-diaminobenzoic acid cholestenyl, 3,5-diaminobenzoic acid cholestanyl, 3,5- (4-aminobenzoyloxy) cholestane, 3,6-bis (4-aminophenoxy) cholestane, 4- (4'-trifluoromethoxybenzoyloxy) Cyclohexyl-3, 5-diaminobenzoate, 4- (4'- Bis (4 - ((aminophenyl) methyl) phenyl) -4-butylcyclohexane, 1,1-bis (4- (4 - ((aminophenyl) methyl) phenyl) -4-heptylcyclohexane, 1,1-bis (Aminophenyl) methyl) phenyl) -4- (4-heptylcyclohexyl) cyclohexane, and the diamine represented by the formula (A-1). 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.

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 , More preferably 80 mol% or more.

[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 isobutyrate, 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 40 to 99%, still more preferably 45 to 99%. The imidization rate is 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.

<Solvent>

The liquid crystal aligning agent of the present invention is constituted such that at least one of polyamic acid and polyimide is dissolved and contained in an organic 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, (B) as an essential component. These solvents (B) all have a high boiling point and a high solubility in polyamic acid and polyimide. Therefore, even when the printing is performed for a long time, the volatilization of the solvent from the printing machine is small and the precipitation of the polymer can be suppressed.

(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 in 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 and a cyclohexyl group. 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 .

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

From the viewpoint of improving the solubility of the polymer contained in the liquid crystal aligning agent, the solvent (B) is preferably used in an amount of 5% by weight or more based on the total solvent contained in the liquid crystal aligning agent, more preferably 10% Is more preferable. The upper limit of the content of the solvent (B) is preferably 90% by weight or less, more preferably 60% by weight or less, further preferably 50% by weight or less based on the total amount of the solvent contained in the liquid crystal aligning agent. Or less. The solvent (B) may be used alone or in combination of two or more.

As the solvent used in the preparation of the liquid crystal aligning agent of the present invention, other solvents other than the above-mentioned solvent (B) include N-methyl-2-pyrrolidone,? -Butyrolactone, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate N-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol (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, di Diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether (DPM), 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.

The liquid crystal aligning agent of the present invention preferably contains dipropylene glycol monomethyl ether (DPM) as the other solvent. By using the above-mentioned solvent (B) in combination with DPM as a solvent to be contained in the liquid crystal aligning agent, printing property for a long time can be further improved.

<Other components>

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

[Other Polymers]

The other polymer may be used for improving solution characteristics and electrical properties. Examples of such another polymer include a polyamic acid (hereinafter referred to as "other polyamic acid") obtained by reacting a diamine containing no compound (a1) with a tetracarboxylic acid dianhydride (hereinafter referred to as "other polyamic acid"), Polyamide, polysiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate, poly ) Acrylate, and the like. Examples of the tetracarboxylic acid dianhydrides and diamines used for synthesizing other polyamic acids and other polyimides include those exemplified as compounds used for synthesizing the polymer (A).

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.

[Oxetanyl group-containing compound]

The oxetanyl group-containing compound can be used for improving the mechanical strength of the liquid crystal alignment film and adhesion to the substrate surface. Examples of the oxetanyl group-containing compound include 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, di [2- (3-oxetanyl) Methoxy] benzene, 1,4-bis [(3-ethyloxetan-3-yl) methoxy] benzene, [(3-ethyloxetane-3-yl) methoxy] biphenyl, 2,2'-bis [(3-ethyl-3-oxetanyl) methoxy] biphenyl, 3,3 ' (3-ethyloxetan-3-yl) methoxy] biphenyl, 2,7-bis [ Bis [(3-ethyloxetan-3-yl) methoxymethyl] norbornane, 2,2'-bis [ Methyl-propane-1,3-diol, 2,4,6-O-tris [(3-ethyloxetan- Ethyl oxetan-3-yl) methyl] cyanuric acid, oxetanylsil sesquioxane, 3-ethyl-3-hydroxymethyloxetane, ETARNACOLL OXBP (manufactured by Ube Chemical Industries, '- (1,3- (2- (3-ethyl-3-oxetanylmethoxy) methyl] ethane, dicyclopentenylbis (3-ethyloxetane) Ethyl-3-oxetanylmethyl) ether, triethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethoxy) butane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, ditrimethylolpropane tetrakis Methyl) ether, and the like.

When the oxetanyl group-containing compound is blended, the compounding ratio thereof is preferably 40 parts by weight or less, more preferably 30 parts by weight or less, based on 100 parts by weight of the total amount of the polymers.

[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-ureidopropyltriethoxy 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-diazanonate, Benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N- 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.

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. At this time, 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 further heating after forming the coating film, Or an imidized coating film may be used.

[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 so-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 the like.

(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 with respect to the solution adjusted to a polymer concentration of 10% by weight by using a predetermined solvent.

[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 α 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;

Synthesis 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) (0.02 mole) of cholestanyl diaminobenzoate (HCDA), 4.9 g (0.01 mole) of cholestanyloxy-2,4-diaminobenzene (HCODA) and 7.6 g of 3,5-diaminobenzoic acid (0.05 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. 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.

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

(0.1 mole) of TCA as tetracarboxylic dianhydride, 5.4 g (0.05 mole) of PDA as diamine, 10.5 g (0.02 mole) of HCDA, 4.9 g (0.01 mole) of HCODA and 4,4'- 5.4 g (0.02 mol) of 1'-biphenyl-2,2'-dicarboxylic acid (DBCA) was dissolved in 195 g of NMP, and the reaction was carried out at 60 ° C for 6 hours to obtain a solution containing 20% by weight 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 33 mPa · s.

Subsequently, 452 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 fresh NMP solvent to obtain a solution containing 22% by weight of polyimide (PI-2) having an imidization rate of about 67%. A small amount of the obtained polyimide solution was collected, and a solution viscosity of 29 mPa · s was measured using NMP as a solution having a polyimide concentration of 10% by weight.

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

(0.10 mole) of TCA as tetracarboxylic dianhydride, 5.4 g (0.05 mole) of PDA as diamine, 10.5 g (0.02 mole) of HCDA, 5.0 g (0.01 mole) of HCODA, ) Methane (BCPM) was dissolved in 196 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 34 mPa · s.

Subsequently, 455 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 fresh NMP solvent to obtain a solution containing 22% by weight of polyimide (PI-3) having an imidization rate of about 73%. A small amount of the obtained polyimide solution was collected, and a solution viscosity of 29 mPa · s was measured using NMP as a solution having a polyimide concentration of 10% by weight.

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

(0.10 mole) of TCA as tetracarboxylic dianhydride, 4.3 g (0.04 mole) of PDA as diamine, 10.5 g (0.02 mole) of HCDA, 4.9 g (0.01 mole) of HCODA, and 4,4'-diaminodiphenylmethane (0.02 mole) of DDM and 1.5 g (0.01 mole) of DAB were dissolved in 190 g of NMP, and the reaction was carried out at 60 占 폚 for 6 hours to obtain a solution containing 20 mass% 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 102 mPa · s.

Next, 442 g of NMP was added to the obtained polyamic acid solution, 7.9 g of pyridine and 10.2 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 22% by weight of polyimide (PI-4) having an imidization rate of about 52%. A small amount of the obtained polyimide solution was collected, and a solution viscosity of 60 mPa · s was measured by adding NMP to a solution having a polyimide concentration of 10% by weight.

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

(0.04 mole) of PDA as a diamine, 10.5 g (0.02 mole) of HCDA, 5.0 g (0.01 mole) of HCODA and 2.7 g (0.01 mole) of DBCA as a diamine and 22.5 g (0.1 mole) of TCA as a tetracarboxylic dianhydride. g (0.02 mol) was dissolved in 196 g of NMP, and the reaction was carried out at 60 DEG C for 6 hours to obtain a solution containing 20% by weight 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 44 mPa · s.

Subsequently, 455 g of NMP was added to the obtained polyamic acid solution, 7.9 g of pyridine and 10.2 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 22% by weight of a polyimide (PI-5) having an imidization rate of about 50%. A small amount of the obtained polyimide solution was collected and NMP was added thereto to obtain a solution having a polyimide concentration of 10% by weight, and the solution viscosity was 31 mPa · s.

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

25.1 g (0.1 mole) 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 mol) of HCDA, 5.0 g (0.01 mol) of HCODA and 7.6 g (0.05 mol) of DAB were dissolved in 202 g of NMP and reacted at 60 DEG C for 6 hours to obtain 20 wt% 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 44 mPa · s.

Subsequently, 468 g of NMP was added to the obtained polyamic acid solution, 11.9 g of pyridine and 15.4 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 22% by weight of polyimide (PI-6) 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 33 mPa · s.

[Synthesis Example 7: Synthesis of polyimide (PI-7)] [

(0.02 mole) of PDA as a diamine, 10.4 g (0.02 mole) of HCDA, 4.9 g (0.01 mole) of HCODA, 3.8 g (0.025 mole) of DAB, and 22.4 g (0.1 mole) of TCA as a tetracarboxylic acid dianhydride. (4-aminophenyl) -2,3-dihydro-1, 3-dihydro-1,3,3-trimethyl- 6.7 g (0.025 mol) of a mixture (TMDA) of 3-trimethyl-1H-inden-6-amine was dissolved in 202 g of NMP and reacted at 60 ° C for 6 hours to obtain a solution containing 20% by weight 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% by weight was 81 mPa · s.

Subsequently, 468 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 fresh NMP solvent to obtain a solution containing 22% by weight of polyimide (PI-7) 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 49 mPa · s.

[Synthesis Example 8: Synthesis of polyimide (PI-8)] [

(0.04 mole) of PDA as a diamine, 10.4 g (0.02 mole) of HCDA, 4.9 g (0.01 mole) of HCODA, 3.0 g (0.02 mole) of DAB, and 25.0 g (0.1 mole) of BODA as a tetracarboxylic dianhydride. g (0.01 mol) was dissolved in 202 g of NMP, and the reaction was carried out at 60 占 폚 for 6 hours to obtain a solution containing 20% by weight 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 49 mPa · s.

Subsequently, 468 g of NMP was added to the obtained polyamic acid solution, 7.9 g of pyridine and 10.2 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 22% by weight of polyimide (PI-8) having an imidization rate of about 49%. A small amount of the obtained polyimide solution was collected, and the solution viscosity was measured to be 34 mPa · s as a solution having a polyimide concentration of 10% by weight by adding NMP.

[Synthesis Example: Synthesis of polyimide (PI-9)] [

(0.07 mol) of PDA as diamine, 5.0 g (0.01 mol) of HCODA and 10.5 g (0.02 mol) of HCDA were dissolved in 182 g of NMP and the mixture was stirred at 60 占 폚 for 6 The reaction was carried out for a time 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 95 mPa · s.

Then, 423 g of NMP was added to the obtained polyamic acid solution, 11.9 g of pyridine and 15.4 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 22% by weight of polyimide (PI-9) having an imidization rate of about 67%. 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 49 mPa · s.

Synthesis Example 10: Synthesis of polyimide (PI-10)

(0.07 mole) of DDM as diamine, 10.4 g (0.02 mole) of HCDA and 4.9 g (0.01 mole) of HCODA as a diamine were dissolved in 206 g of NMP, The reaction was carried out for a time 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 100 mPa · s.

Next, 478 g of NMP was added to the obtained polyamic acid solution, 11.8 g of pyridine and 15.2 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 22% by weight of polyimide (PI-10) having an imidization rate of about 66%. A small amount of the obtained polyimide solution was collected and NMP was added thereto to obtain a solution having a polyimide concentration of 10% by weight, and the solution viscosity was 59 mPa · s.

Synthesis Example 11: Synthesis of polyimide (PI-11)

A polyamic acid solution was obtained in the same manner as in Synthesis 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 89 mPa · s.

Then, polyimide was synthesized using the obtained polyamic acid solution. Synthesis was carried out in the same manner as in Synthesis Example 1 except that DMI was used in place of NMP to obtain a solution containing 22% by weight of a polyimide (PI-11) having an imidization rate of about 65%. 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 57 mPa · s.

Synthesis Example 12: Synthesis of polyimide (PI-12)

A polyamic acid solution was obtained in the same manner as in Synthesis 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 32 mPa · s.

Then, polyimide was synthesized using the obtained polyamic acid solution. Synthesis was carried out in the same manner as in Synthesis Example 2 except that NEP was used instead of NMP, thereby obtaining a solution containing 22% by weight of a polyimide (PI-12) having an imidization rate of about 66%. 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 28 mPa · s.

&Lt; Preparation of liquid crystal aligning agent &

[Example 1]

NMP, ethylene glycol-mono-n-butyl ether (BC) and 1,3-dimethyl-2-imidazolidinone (DMI) were added as a solvent to a solution containing polyimide (PI- And a solution having a solvent composition of NMP: BC: DMI = 30: 50: 20 (weight ratio) and a solid content concentration of 6.5% by weight. This solution was filtered using a filter having a pore size of 1 탆 to prepare a liquid crystal aligning agent (S-1).

[Examples 2 to 33 and Comparative Examples 1 to 6]

(S-2) to (S-33) and (SR-1) were prepared in the same manner as in Example 1, except that the polyimide used and the solvent composition were changed as described in the following Table 1, ) To (SR-6) were prepared.

&Lt; Evaluation of printability &gt;

For the liquid crystal aligning agent prepared as described above, the printing property (long-term printing property) when printing on the substrate was performed for a long time was evaluated. The evaluation was carried out as follows. First, liquid crystal aligning agent (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 actual manufacturing process of the liquid crystal display element but is an operation performed so that the printing of the liquid crystal aligning agent is intentionally performed under a severe condition.

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 coating film was observed under a microscope with a magnification of 20 times to evaluate the printing property for a long time. In the evaluation, the precipitation of polyimide was observed in the case of no precipitation of polyimide from the first printing after the co-operation to be good and the precipitation of polyimide was observed in the first printing after the co-operation, The case where the precipitation of the polyimide was not observed was evaluated as good (?), And the case where the precipitation of the polyimide was observed even after the repetitive printing was repeated five times was evaluated as poor (X). The evaluation results are shown in Table 1 below. In addition, in a liquid crystal aligning agent having good printability, it is experimentally confirmed that the precipitation of polyimide is lost (lost) while the substrate is continuously fed.

Furthermore, the printing performance of the liquid crystal aligning agent for a long period of time was evaluated in the same manner as above by changing the number of times of the ball operation 15 times, 20 times, and 25 times. The evaluation results are also shown in Table 1 below.

&Lt; Production of liquid crystal display element &

[Production Example 1]

The liquid crystal aligning agent (S-1) prepared above was applied to the transparent electrode surface of a glass substrate with a transparent electrode formed of an 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, an epoxy resin adhesive containing an aluminum oxide spheres having a diameter of 5.5 占 퐉 was applied to one of the outer edges of the pair of substrates having the liquid crystal alignment film, and then the other face of the liquid crystal alignment film was pressed and bonded to 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 the liquid crystal injection port was sealed with an acrylic photo-curable adhesive, whereby the first liquid crystal cell C1-1 . Further, a pair of substrates with a liquid crystal alignment film was separately prepared by the same method as above, and the substrates were allowed to stand for 24 hours under the conditions of a humidity of 33% and 23 占 폚. Then, using the pair of substrates, To prepare a liquid crystal cell (C2-1).

[Production Examples 2 to 35]

(S-2) to (S-33) and (SR-1) to (SR-6), the liquid crystal aligning agent to be used was changed to the liquid crystal aligning agent The first liquid crystal cells C1-2 to C1-33, CR1-1 to CR1-6 and the second liquid crystal cells C2-2 to C2-33, (CR2-6), respectively.

<Evaluation of tolerance to neglect>

A voltage of 3 V was applied to each of the first liquid crystal cells prepared above at 70 캜 for an application time of 60 microseconds and a span of 1670 milliseconds and then the voltage maintenance ratio after 1670 milliseconds after the application was released was measured using a VHR- 1. This value was set as the initial voltage holding ratio (VHR1) (%). Similarly, for each of the second liquid crystal cells, the voltage holding ratio was measured in the same manner as described above, and the value was set as the voltage holding ratio (VHR2) [%]. The difference (? VHR) (%) between the voltage holding ratios of the first liquid crystal cell and the second liquid crystal cell was calculated from the following equation (2), and the tolerance was evaluated based on the calculated value. The results are shown in Table 1 below. Further, the smaller the? VHR, the better the tolerance to neglect.

 ? VHR (%) = VHR1-VHR2 ... (2)

The symbols of the solvent composition 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

h: dipropylene glycol monomethyl ether (DPM)

As shown in Table 1, in the liquid crystal aligning agents of the examples, no precipitation of polyimide was observed from the first printing of the main printing in the main printing after 10 times of the blank operation. In addition, even if the number of times of the ball operation was increased by 20 times or 25 times, the precipitation of polyimide was not observed from the first printing of the first printing, or the precipitation of polyimide was lost until the fifth printing was completed. On the other hand, in the liquid crystal aligning agent of the comparative example, when the number of times of co-operation was increased by 20 times, precipitation of polyimide was observed in all of the five main prints. From these results, it was found that the liquid crystal aligning agents of Examples 1 to 33 were less liable to precipitate polyimide than the comparative examples and printability (printing property for a long time) was good even when printing was continuously performed for a long time.

Further, from the results of Examples 6, 14, and 23, it was found that the printing properties for a long time can be further improved by using DPM as a solvent in combination. Further, in the liquid crystal aligning agents of Examples 26 to 29, not only the printing property for a long time is good but also the liquid crystal alignment film capable of maintaining a good electric characteristic can be formed with a small decrease in the voltage holding ratio even when the liquid crystal alignment film is left for a long time I know.

Claims (7)

A) a diamine containing tetracarboxylic dianhydride and a diamine compound (a1) having at least one carboxyl group in the molecule (provided that diaminobenzene having a disubstituted amino group substituted with an alkenyl group having 2 or 3 carbon atoms is excluded) (A) selected from the group consisting of a polyamic acid obtained by reacting a polyamic acid and a polyimide obtained by dehydrocondensing the polyamic acid,
B) at least one kind of solvent (B) 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;
Wherein the content of the diamine compound (a1) is from 10 mol% to 80 mol% based on the total amount of the diamine used in the synthesis of the polyamic acid,

(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 (B) is 10% by weight 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. The method according to claim 1,
Wherein the polymer (A) is at least one selected from the group consisting of 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-inden-5- ) -2,3-dihydro-1,3,3-trimethyl-1H-inden-6-amine. 5. The method according to any one of claims 1 to 4,
A liquid crystal aligning agent further containing dipropylene glycol monomethyl ether as a solvent. A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of claims 1 to 4. A liquid crystal display element comprising the liquid crystal alignment film according to claim 6.