KR101503933B1 - Liquid crystal aligning agent and liquid crystal display - Google Patents

Abstract

The present invention relates to a liquid crystal aligning agent containing a polyamic acid obtained by using an aliphatic tetracarboxylic acid dianhydride represented by the following formula (1) and p-phenylenediamine and an imidized polymer thereof. The liquid crystal aligning agent exhibits good applicability and a high initial voltage holding ratio and can provide a liquid crystal alignment film having a small decrease in voltage holding ratio even if a light or thermal stress is applied to the liquid crystal display element or the liquid crystal display element is driven for a long time.

≪ Formula 1 >

(Wherein R ¹ to R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and m and n each independently represent an integer of 0 to 3)

Liquid crystal aligning agent, polyamic acid, imidized polymer

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal aligning agent,

The present invention relates to a novel liquid crystal aligning agent and a liquid crystal display element. More specifically, the present invention relates to a liquid crystal composition which has a structure derived from a specific aliphatic tetracarboxylic dianhydride, exhibits excellent applicability at the time of formation of a liquid crystal alignment film, exhibits a high voltage holding ratio, applies a stress caused by light or heat to the liquid crystal panel for a long time, And a liquid crystal alignment film formed from the liquid crystal aligning agent and a liquid crystal display element comprising the liquid crystal alignment film.

Since liquid crystal electronic calculators have been mass-produced for the first time, liquid crystal display devices such as liquid crystal displays, which are representative of liquid crystal displays from the viewpoints of space saving and low power consumption, have been widely used in the fields of watches, portable games, word processors, notebook personal computers, car navigation systems, Mobile phones, various monitors, liquid crystal televisions, and the like, and various applications are underway, and active development is continuing. As the liquid crystal display element, a TN (Twisted Nematic) type liquid crystal display element or a TN type liquid crystal display element in which a nematic liquid crystal having positive dielectric anisotropy is used to continuously tilt the liquid crystal molecule from one substrate on the major axis to another substrate by 90 degrees STN (Super Twisted Nematic) type liquid crystal display devices which have a higher contrast than liquid crystal display devices are widely used. Recently, in order to further improve the display quality of the liquid crystal display, VA (Vertical Alignment) type liquid crystal display elements and IPS (In Plane Switching) type liquid crystal display elements with small viewing angle dependency, Excellent optical compensation bend (OCB) type liquid crystal display devices are being developed.

In a liquid crystal display element, a member for controlling the alignment of the liquid crystal is a liquid crystal alignment film. The liquid crystal alignment film may be formed by applying a liquid crystal aligning agent containing an imidized polymer obtained by imidizing a polyamic acid or the polyamic acid to a substrate by a roll coater method, a spinner method, a flexo printing method, an ink jet method or the like, And the like. Here, the uneven application of the liquid crystal alignment film leads directly to the orientation deficiency of the liquid crystal, which causes the display quality of the liquid crystal panel to remarkably deteriorate. In the conventional polyimide-containing liquid crystal aligning agent, studies have been made to increase the imidization rate of the polyimide to improve the electrical characteristics such as the voltage retention rate. However, since the high imidization rate and the application property of the liquid crystal aligning agent are interchangeable Therefore, development of a liquid crystal aligning agent that satisfies excellent electric characteristics and coating properties has been desired. As a method for improving the voltage holding ratio up to now, there have been known a method of adding a polyfunctional epoxy compound to a polyamic acid (JP 10-168455 A), a tetracarboxylic acid dianhydride or diamine as a raw material of a polyamic acid and an imidized polymer (Japanese Patent No. 3572690 and Japanese Patent Laid-Open No. 2001-228481), and an example of adding an acrylic polymer to polyamic acid (Japanese Patent No. 3206169) have been reported. However, the improvement effect of the initial voltage retention rate and its reliability (that is, the application of light or thermal stress to the liquid crystal panel or the change of the voltage retention rate even after driving the liquid crystal panel for a long time) by these reports is not sufficient, It has not been studied from the viewpoint of improving the coating property at the time of forming the liquid crystal alignment film. In recent years, as liquid crystal panels are applied to liquid crystal TVs and high-quality monitors, it has been desired to improve not only high-voltage retention ratios but also reliability of voltage retention ratios and coating properties in forming liquid crystal alignment films in order to achieve high- have.

SUMMARY OF THE INVENTION The present invention has been accomplished on the basis of the above-described circumstances, and an object of the present invention is to provide a liquid crystal display device which exhibits good applicability and a high initial voltage holding ratio, and which, when light or thermal stress is applied to a liquid crystal display element, And a liquid crystal alignment film formed from the liquid crystal aligning agent. The present invention also relates to a liquid crystal display device capable of displaying a beautiful image over a long period of time by a liquid crystal alignment film formed from the liquid crystal aligning agent.

Other objects and advantages of the present invention will be apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are attained by the use of at least one aliphatic tetracarboxylic acid dianhydride represented by the following general formula (1) and optionally other tetracarboxylic acid dianhydrides and p-phenylenediamine, , And a liquid crystal aligning agent containing at least one polymer selected from an imidized polymer obtained by imidizing the polyamic acid.

(Wherein R ¹ to R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and m and n each independently represent an integer of 0 to 3)

Further, according to the present invention, the above object of the present invention is achieved by a liquid crystal display element comprising a liquid crystal alignment film formed of the above-mentioned liquid crystal aligning agent.

EFFECTS OF THE INVENTION [

According to the liquid crystal aligning agent of the present invention, it is possible to provide a liquid crystal alignment film which exhibits good applicability, a high initial voltage holding ratio, applies a light or thermal stress to a liquid crystal display element, An orientation agent is obtained.

BEST MODE FOR CARRYING OUT THE INVENTION [

Hereinafter, the present invention will be described in detail.

[Polyamic acid and imidized polymer]

The polyamic acid to be used in the present invention may be at least one kind of aliphatic tetracarboxylic acid dianhydride represented by the above formula (1), other tetracarboxylic acid dianhydrides and p-phenylenediamines, if necessary, . The imidized polymer used in the present invention is obtained by dehydrating and ring closure of the polyamic acid.

The liquid crystal aligning agent of the present invention is a tetracarboxylic acid dianhydride for synthesizing a polyamic acid and / or an imidized polymer contained in the liquid crystal aligning agent, wherein at least one of the tetracarboxylic acid dianhydrides represented by the formula (1) The use of other tetracarboxylic acid dianhydrides in accordance with the present invention exhibits an excellent and excellent application property and a high initial voltage holding ratio, and the liquid crystal display element exhibits high reliability. In the present invention, the polyamic acid synthesized by using the tetracarboxylic acid dianhydride represented by the above formula (1) can be obtained by subjecting a polyarylate synthesized using a tetracarboxylic acid dianhydride Since the liquid crystal alignment film having a high imidization rate can be obtained, the liquid crystal alignment layer exhibits a high initial voltage holding ratio, and when light or thermal stress is applied to the liquid crystal display element or the liquid crystal panel is driven for a long time, It is possible to provide a liquid crystal alignment film having a small decrease in the retention ratio.

In the present invention, the use ratio of the tetracarboxylic dianhydride represented by the formula (1) is preferably 5 to 100 mol%, more preferably 25 to 100 mol%, based on the total tetracarboxylic dianhydride, And particularly preferably 50 to 100 mol%.

In Formula 1, R ¹ to R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and particularly preferably a hydrogen atom or a methyl group. m and n are each independently an integer of 0 to 3, preferably 0 or 1, particularly preferably a structure represented by the following formula (2) wherein m = n = 0 or a structure represented by the following formula Is preferable.

The tetracarboxylic acid dianhydrides represented by the above formula (1) may be used alone or in combination of two or more.

Other tetracarboxylic acid dianhydrides which are different from the tetracarboxylic acid dianhydrides represented by the above formula (1) and optionally used together with the tetracarboxylic dianhydrides represented by the above formula (1) For example, butane tetracarboxylic acid dianhydride, 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride Water, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3-dichloro-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5 -Cyclohexanetetracarboxylic dianhydride, 3,3 ', 4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 3,5,6 -Tricarboxy norbornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofuran tetracarboxylic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetra Dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro- Methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2- c] -furan-1,3-dione, 1,3,3a, 4,5,9b -Hexahydro-5-ethyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2- c] , 4,5,9b-hexahydro-7-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [ , 1,3,3a, 4,5,9b-hexahydro-7-ethyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [ -1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) 2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-ethyl-5- (tetrahydro- -Naphtho [l, 2-c] -furan-l, 3-dione, 1,3,3a , 4,5,9b-hexahydro-5,8-dimethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [ Cyclohexene-1,2-dicarboxylic acid anhydride, bicyclo [2.2.2] -oct-7-ene- Tetra carboxylic acid dianhydride, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 '- (tetrahydrofuran- -Dione), 3,5,6-tricarboxy-2-carboxy norbornane-2: 3,5: 6- dianhydride, bicyclo [3.3.0] octane-2,4,6,8- Alicyclic and alicyclic tetracarboxylic acid dianhydrides such as a compound represented by the following Chemical Formulas 4 and 5;

(Wherein R ¹⁵ and R ¹⁷ each represent a divalent organic group having an aromatic ring, R ¹⁶ and R ¹⁸ each represent a hydrogen atom or an alkyl group, and a plurality of R ¹⁶ and R ¹⁸ which may be present may be the same or different has exist)

Pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,3,3', 4'-benzophenonetetracarboxylic acid dianhydride, 2,2 ', 3 , 3'-benzophenonetetracarboxylic acid dianhydride, 3,3 ', 4,4'-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 2 , 3,6,7-naphthalenetetracarboxylic acid dianhydride, 3,3 ', 4,4'-biphenyl ether tetracarboxylic acid dianhydride, 3,3', 4,4'-dimethyldiphenylsilane tetra Carboxylic acid dianhydride, 3,3 ', 4,4'-tetraphenylsilane tetracarboxylic acid dianhydride, 1,2,3,4-furan tetracarboxylic acid dianhydride, 4,4'-bis (3 , 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, Phenoxy) diphenylpropane dianhydride, 3,3 ', 4,4'-perfluoroisopropylidene diphthalic acid dianhydride, 3,3', 4,4'-biphenyltetracarboxylic acid (Triphenylphthalic acid) dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m- Diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4'-diphenylmethane dianhydride, ethylene glycol-bis (anhydrotrimellitate), propylene glycol-bis (anhydrotrimellitate) Bis (anhydrotrimellitate), 1,6-hexanediol-bis (anhydrotrimellitate), 1,8-octanediol-bis (anhydrotrimellitate) Aromatic tetracarboxylic acid dianhydrides such as 2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate) and compounds represented by the following general formulas (6) to (8).

Among them, preferred are butanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 5- (2,5-dioxotetrahydrofuranyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 1,3,3a, 4,5,9b-hexahydro- 1,2-c] furan-1,3-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, 1,3,3a, 4,5,9b- (Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [l, 2-c] furan-l, 3-dione, bicyclo [2.2. 2] -oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, 3-oxabicyclo [3.2.1] octane-2,4-dione- 3, 5: 6-dianhydride, bicyclo [3.3.0] heptan-2- Octane-2,4,6,8-tetracarboxylic acid dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic acid dianhydride, 2,3,3', 4 '- benzophenone tetracarboxylic acid dianhydride, 2,2', 3,3'-benzophenonetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenylsulfonetetracarboxylic acid dianhydride, Naphthalenetetracarboxylic acid dianhydride, compounds represented by the following general formulas (9) to (11) and compounds represented by the following general formulas (5) Is preferable from the viewpoint of being able to exhibit good liquid crystal alignability. Particularly preferred are 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,4,5 -Cyclohexanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-di 3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro- Dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3.2.1] octane- 3,3 '- (tetrahydrofuran-2', 5'-dione), 3,5,6-tricarboxy-2-carboxynorbornane- -0] octane-2,4,6,8-tetracarboxylic acid dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic acid dianhydride and . ≪ / RTI >

Other tetracarboxylic acid dianhydrides different from the tetracarboxylic dianhydrides represented by the above formula (1), which are used as necessary, may be used singly or in combination of two or more.

[Diamine]

The liquid crystal aligning agent of the present invention exhibits a high initial voltage maintaining ratio by containing p-phenylenediamine as an essential component and optionally using other diamine as a diamine. The proportion of the p-phenylenediamine used in the present invention is preferably 5 to 100 mol%, more preferably 10 to 100 mol%, and particularly preferably 25 to 100 mol% based on the total diamine.

Other diamines are preferred compounds depending on the manner in which the liquid crystal aligning agent of the present invention is used. When the liquid crystal aligning agent of the present invention is used in a TN system, an STN system, an OCB system or a VA system, as a diamine used for the synthesis of the main component polymer, besides p-phenylenediamine, a pretilt represented by the following formula It is preferable to use diamines having respective expression sites in combination.

(Wherein R ⁷ and R ⁸ are each independently a hydrogen atom or a methyl group, R ⁹ is a linear or branched alkyl group having 1 to 20 carbon atoms, and R ¹⁰ and R ¹¹ are each independently a divalent organic group )

(Wherein, a is 0 or 1 and R ¹² is an ether bond (-O-), a carbonyl group (-CO-), a carbonyloxy group (-COO-), an oxycarbonyl group (-OCO-) -NHCO-, -CONH-), a thioether bond (-S-) and a methylene group, R ¹³ is a divalent organic group different from R ¹² , and R ¹⁴ is a steroid skeleton A group having a fluorine atom and a group having a straight chain or branched alkyl group having 1 to 30 carbon atoms)

These diamines having these pretilt angle expression sites are used singly or in combination of two or more.

Specific examples of the diamine represented by the formula (13) include compounds represented by the following formulas (15) and (16), respectively.

Specific examples of the diamine represented by the formula (14) include compounds represented by the following formulas (17) to (21).

When the liquid crystal aligning agent of the present invention is used for a TN system, an STN system, an OCB system, a VA system, a TN system, an STN system or an OCB system, at least one pretilt The pretilt angle of the liquid crystal of 1 to 30 DEG can be stably expressed by using the diamine having each expression site. In this case, the amount of the diamine having a pretilt angle expression site is preferably 0.5 to 30 mol%, more preferably 0.7 to 20 mol%, particularly preferably 1 to 15 mol% based on the total diamine. As the diamines having a pretilt angular expression site, it is particularly preferable to use at least one of the diamines represented by each of the above formulas (15) to (21).

In the case where the liquid crystal aligning agent of the present invention is used in the VA system among the TN system, the STN system, the OCB system and the VA system, superior linear orientation of liquid crystal is exhibited. Therefore, among the diamines having the pretilt angle- The amount of the diamine to be used is preferably 8 to 60 mol%, more preferably 9 to 50 mol%, particularly preferably 10 to 25 mol%, based on the total diamine. As the diamines having a pretilt angular expression site, it is preferable to use the diamines represented by the above-mentioned formulas (17) to (21), especially the diamines represented by the above formula (17) or (18).

On the other hand, when the liquid crystal aligning agent of the present invention is used in the IPS system or the FFS system, the diamine having the pretilt angle expression site can be used, but the diamine other than the diamine having the pretilt angular expression site It is preferable to synthesize the main component polymer.

Examples of other diamines other than the diamines having p-phenylenediamine used for synthesis of the main component polymer of the liquid crystal aligning agent of the present invention and the pretilt angular expression site include the following diamines.

m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone , 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, (4'-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4'-aminophenyl) 1,3,3-trimethylindane, 3,4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone Bis (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2- (Aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,4- (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10- (4-aminophenyl) fluorene, 4,4'-methylene-bis (2-chloroaniline), 2,2 ', 5,5 '-Tetrachloro-4,4'-diaminobiphenyl, 2,2'-dichloro-4,4'-diamino-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy- 4,4'- (p-phenylene isopropylidene) bisaniline, 4,4 '- (m-phenyleneisopropylidene) bisaniline, 2,2'-bis (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4'-diamino-2,2'-bis (trifluoromethyl) (4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl, 1,3-bis (4- Aminophenoxy) -2,2-dimethylpropane, and 4,4'-bis (4-aminophenoxy) biphenyl;

Diaminopyridine, 5, 6-diamino-2,3-dicyanopyrimidine, 5, 6-diamino-2,3-dicyanopyrimidine, Dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, Diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4- 2,4-diamino-6-methyl-s-triazine, 2,4-diamino-1,3,5-triazine, 4,6- Vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6-diaminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5- Diamino-1,2,4-triazole, 6,9-diamino-2-ethoxy acridactate, 3,8-diamino-6-phenylphenanthridine, (4-aminophenyl) phenylamine, and compounds represented by the following formulas (22) and (23), respectively, A diamine having two primary amino groups and a nitrogen atom other than the primary amino group;

(Wherein R ¹⁹ represents a monovalent organic group having a ring structure including a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, and X represents a divalent organic group)

(Wherein R ²⁰ represents a divalent organic group having a ring structure including a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine)

There may be mentioned 1,3-bis (aminomethyl) cyclohexane, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, Methylenediamine, 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanedanilinedimethylenediamine, tricyclo [6.2.1.0 ^2,7 ] Aliphatic and alicyclic diamines such as undecylenedimethyldiamine and 4,4'-methylenebis (cyclohexylamine);

A diaminoorganosiloxane represented by the following formula (24);

(Wherein R ²¹ represents a hydrocarbon group of 1 to 12 carbon atoms, and plural R ^{21 s} present may be the same or different, p is an integer of 1 to 3, and q is an integer of 1 to 20)

. These p-phenylenediamines and other diamines other than the diamines having the pretilt angle expression sites are used alone or in combination of two or more.

Of these, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4'- Bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- ) Phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 1,4-bis (4-aminophenoxy) benzene, ) Biphenyl, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, 2,6- diamino Pyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacrylidine, a compound represented by the following Chemical Formula 25 in the compound represented by Chemical Formula 22, (Aminomethyl) cyclohexane, 1,4-cyclohexanediamine, 4,4'-methylenebis 3,3 '- (tetramethyldisiloxane-1,3-diyl) bis (propylamine) represented by the following Chemical Formula 27 in the compound represented by Chemical Formula 24 is preferable.

Particularly preferable examples include 4,4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 2,7- (Propylamine), 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,3- Bis (aminomethyl) cyclohexane, 2,2-bis (4-aminophenyl) hexafluoropropane and 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl .

<Synthesis of polyamic acid>

The ratio of the tetracarboxylic dianhydride to the diamine used in the synthesis reaction of the polyamic acid of the present invention is from 0.2 to 2 equivalents of the acid anhydride group of the tetracarboxylic dianhydride with respect to one equivalent of the amino group contained in the diamine , More preferably from 0.3 to 1.2 equivalents.

The synthesis reaction of the polyamic acid is carried out in an organic solvent at a temperature of preferably -20 to 150 ° C, more preferably 0 to 100 ° C. The organic solvent is not particularly limited as long as it can dissolve the polyamic acid to be synthesized. Examples of the organic solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, Non-protonic polar solvents such as dimethyl sulfoxide,? -Butyrolactone, tetramethyl urea, and hexamethylphosphoric triamide; m-cresol, xylenol, phenol, halogenated phenol, and the like. The amount (a) of the organic solvent used is preferably from 0.1 to 30% by weight based on the total amount (a + b) of the reaction solution when the total amount (b) of the tetracarboxylic acid dianhydride and the diamine is used.

Alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbons, etc. which are poor solvents of polyamic acid may be used in the organic solvent in a range that does not cause the production of polyamic acid to be produced. Specific examples of such poor solvent include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, diacetone alcohol, ethylene glycol monomethyl ether, But are not limited to, ethyl lactate, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, (Ethylene glycol) propyl ether, ethylene glycol-i-propyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethyleneglycol-diethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, Glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol di Diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dioxane - dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene and the like. These poor solvents may be used alone or in combination of two or more.

In this way, a reaction solution obtained by dissolving polyamic acid is obtained. Further, this reaction solution is poured into a large amount of a poor solvent to obtain a precipitate, and this precipitate is dried under reduced pressure to obtain a polyamic acid. Further, the polyamic acid can be purified by once or several times the step of dissolving the polyamic acid in an organic solvent and then precipitating it with a poor solvent.

<Imidized Polymer>

The imidized polymer used in the liquid crystal aligning agent of the present invention can be synthesized by dehydrating and ring closure of the polyamic acid. The imidized polymer referred to herein includes a partial imide polymer in which the polyamic acid is partially imidized and a polymer which is 100% imidized, and these are collectively referred to as "imidized polymer ".

The imidization ratio in the imidized polymer used in the liquid crystal aligning agent of the present invention is preferably 10 to 100%, more preferably 20 to 99%, particularly preferably 40 to 98%. Here, the "imidization rate" is a percentage of the number of imide rings relative to the sum of the number of amic acid structures and the number of imide rings in the polymer. At this time, a part of the imide ring may be an isoimide ring.

Examples of the method for synthesizing the imidized polymer include: (I) a method of dehydrating and ring closure by heating the polyamic acid, (II) a method of dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring- To obtain a polymer having a desired imidization ratio by appropriately controlling the above reaction conditions.

The reaction temperature in the method of heating the polyamic acid of (I) is preferably 50 to 300 占 폚, more preferably 100 to 250 占 폚. If the reaction temperature is less than 50 ° C, the dehydration ring-closure reaction does not proceed sufficiently, and if the reaction temperature exceeds 300 ° C, the molecular weight of the resulting imidized polymer may be lowered.

On the other hand, in the method of adding the dehydrating agent and the dehydration ring-closing catalyst to the solution of the polyamic acid of the above (II), for example, an acid anhydride such as acetic anhydride, propionic acid 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 per 1 mol of the repeating unit of the polyamic acid. As the dehydration cyclization catalyst, for example, tertiary amines such as pyridine, collidine, lutidine and triethylamine can be used. However, the dehydrating agent and dehydration ring-closing catalyst are not limited to these examples. 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. The organic solvent used in the dehydration ring closure reaction may be the same as the organic solvent exemplified in the synthesis of the polyamic acid. The reaction temperature of the dehydration ring-closure reaction is preferably 0 to 180 ° C, more preferably 60 to 150 ° C. In addition, the imidized polymer can be purified by carrying out the same operation as the purification method of polyamic acid for the reaction solution thus obtained.

&Lt; Polymer of terminal modification type &

The polyamic acid and the imidized polymer constituting the liquid crystal aligning agent of the present invention may be a terminally modified type having a controlled molecular weight. By using the polymer of the terminal modification type, the coating property and the like of the liquid crystal aligning agent can be improved without impairing the effect of the present invention. Such a terminal modification type can be synthesized by adding an acid anhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when synthesizing polyamic acid. Examples of the acid anhydride include dicarboxylic acid monoanhydride, and examples thereof include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride , and n-hexadecyl succinic anhydride. Examples of the monoamine compound include aniline, cyclohexylamine, p-ethyl aniline, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-decylamine, n-decylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, Octadecylamine, n-eicosylamine, and the like. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

<Logarithmic Viscosity of Polymer>

The value of the logarithmic viscosity (? _Ln ) of the polyamic acid and imidized polymer obtained as described above is preferably 0.05 to 10 dl / g, more preferably 0.05 to 5 dl / g.

The value of the logarithmic viscosity (? _Ln ) in the present invention is determined by measuring the viscosity at 30 ° C for a solution having a concentration of 0.5 g / 100 ml using N-methyl-2-pyrrolidone as a solvent, Is obtained by the following equation (a).

<Liquid Crystal Aligner>

The liquid crystal aligning agent of the present invention is constituted by dissolving polyamic acid and imidized polymer in an organic solvent. The liquid crystal aligning agent of the present invention is preferably a polyamic acid or imidized liquid containing a structure derived from the aliphatic tetracarboxylic acid dianhydride represented by the above formula (1) of the present invention in order to improve the film resistance at the time of forming the liquid crystal alignment film But may also contain other polyamic acid or imidized polymer than the polymer. Such other polyamic acid or imide polymer may be one type or plural types depending on the purpose, in particular 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3-dimethyl- Cyclobutanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, (Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a , 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [ 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 '- (tetrahydrofuran-2', 5'- dione), 3,5,6-tricarboxy- Carboxynorbornane-2: 3,5: 6-dianhydride, bicyclo [3.3.0] octane-2,4,6,8-tetracarboxylic acid dianhydride and pyromellitic acid dianhydride The above acid dianhydride, and p-phenyl Diamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4'-diamino di Bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- ) Phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl, Diamino-2,2'-dimethylbiphenyl, and 3,3- (tetramethyldisiloxane-1,3-diyl) bis (propylamine) is reacted with 1 mol of diamine to obtain 1 It is preferable to add at least one species. The amount of the polyamic acid or the imidized polymer not containing a constituent unit derived from the aliphatic tetracarboxylic dianhydride represented by the above formula (1) is preferably from 1 to 50 parts by weight, Is preferably 10 to 900 parts by weight, more preferably 25 to 500 parts by weight, particularly preferably 100 to 400 parts by weight, based on 100 parts by weight of the total amount of the polymer containing the structural unit.

In the liquid crystal aligning agent of the present invention, in order to improve the initial voltage holding ratio, reduce the amount of change in the voltage holding ratio when applying light or thermal stress to the liquid crystal display element, or driving the liquid crystal display element for a long time , A compound having an epoxy group may be added. Examples of the compound having an epoxy group include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl Ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3, N, N ', N'-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidyl Aminomethyl) cyclohexane, N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N, N, N', N'-tetraglycidyl- -Diaminobenzene, N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenyl ether, N, N, N' '-Dimethyl-4,4'-diaminobiphenyl, and the like. Among these compounds having epoxy groups, a compound having an epoxy group containing a nitrogen atom in a molecule having a mother skeleton as a nucleus is particularly preferable because of excellent reactivity with the polyamic acid and the imidized polymer of the present invention. The addition amount of the compound having an epoxy group is preferably 0 to 60 parts by weight, more preferably 5 to 50 parts by weight, based on 100 parts by weight of the total amount of the polyamic acid and the imidized polymer of the present invention.

The liquid crystal aligning agent of the present invention may also contain a functional silane compound from the viewpoint of improving the adhesion to the substrate surface. 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-triethoxysilylpropyl triethylenetriamine, N- Trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3 , 6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N- Aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, N-bis (oxyethylene ) -3-aminopropyltrimethoxysilane, and N-bis (oxyethylene) -3-aminopropyltriethoxysilane. The amount of these functional silane compounds to be added is preferably 0 to 60 parts by weight, more preferably 0 to 50 parts by weight, based on 100 parts by weight of the total amount of the polyamic acid and the imidized polymer of the present invention.

Examples of the organic solvent constituting the liquid crystal aligning agent of the present invention include the same solvents as those exemplified for use in the synthesis reaction of polyamic acid. Among them, a solvent having a boiling point of 160 占 폚 or higher is preferable from the viewpoint of printing property, and for example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide,? -Butyrolactone, Propyleneglycol, 1,4-butanediol, triethyleneglycol, diacetone alcohol, butyl lactate, butyl acetate, ethyl ethoxyacetate, ethyl lactate, Propylene carbonate, propylene carbonate, propylene carbonate, diethyl oxalate, diethyl malonate, ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, di Ethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, 1,4-dichlorobutane, o-dichlorobenzene and the like . Among these, N-methyl-2-pyrrolidone,? -Butyrolactone, diacetone alcohol, ethylene glycol monobutyl ether (butyl cellosolve), propylene carbonate and diethylene glycol diethyl ether are preferable. Particularly preferable solvent composition is a composition obtained by combining the above solvents, and the composition is such that the polymer is not precipitated in the aligning agent and the surface tension of the aligning agent is in the range of 25 to 40 mN / m.

The solid concentration in the liquid crystal aligning agent of the present invention (the ratio of the total weight of the components from which the organic solvent is removed in the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is selected in consideration of viscous volatility and the like, To 10% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the surface of the substrate to form a coating film which becomes a liquid crystal alignment film. However, when the solid concentration is less than 1% by weight, the film thickness of the coating film becomes too small to obtain a good liquid crystal alignment film, When the solid concentration exceeds 10% by weight, the film thickness of the coating film becomes too large to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal aligning agent is increased and the coating property is lowered.

The viscosity of the liquid crystal aligning agent of the present invention (viscosity measured at 25 캜 using a rotational viscometer for the liquid crystal aligning agent) needs to be appropriately adjusted according to the method of applying the liquid crystal aligning agent, S, more preferably 3 to 50 mPa s, and particularly preferably 3 to 35 mPa s.

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 range of 1.5 to 4.5 wt% is particularly preferable. In the case of the printing method, it is particularly preferable that the solid concentration is in the range of 3 to 9 wt%, and the solution viscosity is accordingly in the range of 12 to 50 mPa · s. In the case of the ink-jet 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 accordingly.

The temperature in the production of the liquid crystal aligning agent of the present invention is preferably 0 ° C to 200 ° C, more preferably 10 ° C to 100 ° C, particularly preferably 20 ° C to 60 ° C.

<Liquid crystal display element>

The liquid crystal display element of the present invention can be produced, for example, by the following method.

(1) The liquid crystal aligning agent of the present invention is applied to one side of a substrate provided with a patterned transparent conductive film by, for example, a roll coater method, a spinner method, a printing method, or an ink jet method, . Here, as a method of applying a liquid crystal aligning agent to a substrate, a spinner method is preferable for a small substrate, a printing method is preferable for a medium type substrate, and an ink jet method is preferable for a large substrate. Examples of the substrate include glass such as float glass and soda glass; A transparent substrate containing plastics such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, and cyclic polyolefin can be used. As the transparent conductive film to be provided on one side of the substrate, an ITO film including indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ), a NESA film containing tin oxide (SnO ₂ ) Etc. may be used. For patterning these transparent conductive films, a photoetching method or a method using a mask in advance is used. As the reflective electrode, a metal such as Al or Ag, or an alloy containing these metals can be used. However, it is not limited to these as long as it has a sufficient reflectance. In applying the liquid crystal aligning agent, a functional silane compound, a functional titanium compound, and the like may be previously applied to the surface of the substrate in order to further improve adhesion between the substrate surface and the transparent conductive film or the reflective electrode and the coating film . After application of the liquid crystal aligning agent, preheating (prebaking) is usually carried out for the purpose of preventing the applied alignment agent from being dropped. The prebaking temperature is preferably 30 to 300 占 폚, more preferably 40 to 200 占 폚, particularly preferably 50 to 150 占 폚. Thereafter, a baking (post baking) process is performed for the purpose of completely removing the solvent. The firing temperature is preferably 80 to 300 占 폚, more preferably 120 to 250 占 폚. In this way, the liquid crystal aligning agent of the present invention forms a coating film which becomes an alignment film by removing the organic solvent after coating. When the liquid crystal aligning agent of the present invention contains a polyamic acid or an imidized polymer having a low imidization ratio, Thereby promoting the dehydration ring closure, so that a more imaged coating film can be obtained. The film thickness of the formed coating film is preferably 0.001 to 1 mu m, more preferably 0.005 to 0.5 mu m.

(2) The orientation of the liquid crystal molecules can be controlled by a rubbing process in which the coated film surface is rubbed in a certain direction with a roll wound with a cloth containing fibers such as nylon, rayon, and cotton. In addition to the rubbing method, a method of controlling the aligning ability by irradiating the surface of the coating film with the polarizing ultraviolet light can also be applied. Further, it is preferable to clean the formed liquid crystal alignment film with isopropyl alcohol and / or pure water in order to remove the fine powder (foreign matter) generated in rubbing treatment or the like and to make the surface of the coated film clean. Further, by partially irradiating the liquid crystal alignment film formed by the liquid crystal aligning agent of the present invention with ultraviolet rays as described in, for example, Japanese Patent Application Laid-Open No. 6-222366 or Japanese Patent Application Laid-Open No. 6-281937, The resist film is partially formed on the rubbed liquid crystal alignment film as described in JP-A-5-107544, and the rubbing process is performed in a direction different from the preceding rubbing process Thereafter, the resist film is removed to change the alignment capability of the liquid crystal alignment film, thereby improving the visual field characteristics of the liquid crystal display element.

(3) Two substrates each having a liquid crystal alignment film formed thereon as described above were prepared, two substrates were disposed opposite each other with a gap (cell gap), the peripheral portions of the two substrates were bonded together using a sealing agent, The liquid crystal is injected and filled in the cell space defined by the substrate surface and the sealant, and the injection hole is sealed to constitute the liquid crystal cell. In addition, by disposing the polarizing plate on the outer surface of the liquid crystal cell, that is, on the outer surface side of each substrate constituting the liquid crystal cell, a liquid crystal display element is obtained.

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

Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals. Among them, a nematic liquid crystal is preferable, and examples thereof include a shiff base liquid crystal, an agar liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, an ester liquid crystal, a terphenyl liquid crystal, a biphenylcyclohexane A liquid crystal, a pyrimidine-based liquid crystal, a dioxane-based liquid crystal, a bicyclooctane-based liquid crystal, a quartz-based liquid crystal and the like. Further, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonanoate and cholesteryl carbonate in the liquid crystal are sold as "C-15" and "CB-15" (manufactured by Merck) And ferroelectric liquid crystal such as chiral agent, p-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate, and the like.

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 .

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples. Measurement of the imidization ratio, measurement of the voltage holding ratio, reliability evaluation of the voltage holding ratio, and printability test in Examples and Comparative Examples were evaluated by the following methods.

[Measurement of imidization rate]

The polymer was dried under reduced pressure at room temperature and then tetramethylsilane was dissolved in dehydrated dimethylsulfoxide (DMSO-d ₆ ) using a superconducting nuclear magnetic resonance absorption apparatus (NMR (EX-90A manufactured by Nippon Denshi Co., ¹ H-NMR was measured as a reference material. From the obtained data, the imidization ratio was calculated from the ratio of the peak area (near 10 ppm) derived from the proton of the NH group in the polymer and the peak area derived from the other proton.

[Measurement of voltage holding ratio]

A voltage of 5 V was applied to the liquid crystal display element with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage maintenance ratio after 167 milliseconds from the application of the release voltage was measured under an atmosphere of 60 deg. VHR-1 manufactured by Toyo Technica Co., Ltd. was used as a measuring device. The case where the voltage holding ratio was 99.0% or more was judged as "good" and the case where the voltage holding ratio was other than 99.0% was judged as "defective ".

[Evaluation of Reliability of Voltage Maintenance Rate]

After the voltage holding ratio was measured by the above-described measuring method, the produced liquid crystal display device was stored in a constant-temperature oven at 100 ° C for 10 days to apply thermal stress, and then cooled to room temperature. The voltage holding ratio of this liquid crystal display element was again measured by the aforementioned measuring method, and the change amount of the voltage holding ratio before and after the thermal stress was calculated. The case where the change amount of the voltage holding ratio was within 5% of the initial value was judged as "good"

[Printing test]

Each of the liquid crystal aligning agents prepared in the following examples and comparative examples (having a total solid concentration of 4.5 to 6.5% by weight) was coated with a liquid crystal alignment film printing machine (manufactured by Nippon Shashin Inks Co., Ltd.) And ITO films having a width of 20 占 퐉 were applied to the transparent electrode surfaces of the glass substrates with transparent electrodes formed in stripes at intervals of 100 占 퐉, preliminary drying was performed at 80 占 폚 for 1 minute on a hot plate, For 10 minutes to form a liquid crystal alignment film having a film thickness of about 60 nm. A peripheral portion and a central portion of the liquid crystal alignment film were observed with a microscope having a magnification of 20 times, and it was judged as "good" when there was no coating irregularity and "bad" when there was coating irregularity. The results of evaluating the printability of each liquid crystal aligning agent are shown in Table 2 below.

Synthesis Example 1 (Synthesis of polyamic acid P-1)

(0.1709 mol) of tetracarboxylic dianhydride represented by the above formula (2), 12.433 g (0.0570 mol) of pyromellitic dianhydride and 18.860 g (0.1744 mol) of p-phenylenediamine as a diamine as tetracarboxylic dianhydride ), 30.376 g (0.0581 mol) of the diamine represented by the above formula (17) was dissolved in 400 g of N-methyl-2-pyrrolidone and reacted at 60 DEG C for 4 hours. The reaction solution was then poured into a very large excess of methyl alcohol to precipitate the reaction product. Thereafter, the resultant was washed with methyl alcohol, and dried at 40 DEG C for 24 hours under reduced pressure to obtain 88 g of a polyamic acid having an inherent viscosity of 0.70 dl / g (referred to as "polymer P-1").

Synthesis Example 3 (Synthesis of imidated polymer P-3)

25.690 g (0.0930 mole) of the tetracarboxylic dianhydride represented by the above formula (3) as a tetracarboxylic dianhydride, 9.2135 g (0.0852 mole) of p-phenylenediamine as a diamine and 4.9668 g 0.0095 mol) was dissolved in 140 g of N-methyl-2-pyrrolidone, and the reaction was carried out at 60 DEG C for 5 hours. The reaction solution was then poured into a very large excess of methyl alcohol to precipitate the reaction product. Thereafter, the solution was washed with methyl alcohol, and dried at 40 DEG C for 24 hours under reduced pressure to obtain 31 g of polyamic acid having an inherent viscosity of 0.72 dl / g. 30 g of the obtained polyamic acid was dissolved in 400 g of N-methyl-2-pyrrolidone, and 6.3 g of pyridine and 8.1 g of acetic anhydride were added and dehydrated and cyclized at 110 ° C for 4 hours. To obtain 26 g of an imidation polymer (referred to as "polymer P-3") having an inherent viscosity of 0.68 dl / g and an imidization ratio of 48%.

Synthesis Example 6 (Synthesis of imidated polymer P-6)

16.7061 g (0.0795 mole) of the tetracarboxylic acid dianhydride represented by the above formula (2) as a tetracarboxylic dianhydride, 2.9198 g (0.0270 mole) of p-phenylenediamine as a diamine and 6.2216 g (0.0397 mol) of 4,4'-diaminodiphenylmethane and 0.1480 g (0.0016 mol) of aniline as a terminal monoamine were dissolved in 140 g of N-methyl-2-pyrrolidone, And reacted at 60 DEG C for 4 hours. The reaction solution was then poured into a very large excess of methyl alcohol to precipitate the reaction product. Thereafter, the resultant was washed with methyl alcohol, and dried at 40 DEG C for 24 hours under reduced pressure to obtain 32 g of polyamic acid having an inherent viscosity of 0.60 dl / g. 30 g of the obtained polyamic acid was dissolved in 400 g of N-methyl-2-pyrrolidone, and 10.8 g of pyridine and 13.9 g of acetic anhydride were added, followed by dehydration cyclization at 110 DEG C for 4 hours. To obtain 27 g of an imidation polymer (referred to as "polymer P-6") having an inherent viscosity of 0.55 dl / g and an imidization rate of 75%.

Synthesis Example 2, Synthesis Examples 4 and 5, and Synthesis Examples 7 to 14, Comparative Synthesis Examples 1 to 5

Tetra carboxylic acid dianhydride and diamine were changed to those shown in the following Table 1, polyamic acid and imidized polymer shown in Table 1 (these are shown in Table 1, respectively) were obtained in the same manner as in Synthesis Example 1, Synthesis Example 3 and Synthesis Example 6, respectively P-2 "," P-4 "," P-5 "," P-7 "to" P-19 "). Each polymer was able to obtain a polymer having the viscosity shown in Table 1 by appropriately adjusting the weight ratio of tetracarboxylic dianhydride and diamine used when synthesizing the corresponding polyamic acid. Further, the imidization ratios of the respective polymers having the imidization ratios shown in Table 1 were obtained by appropriately adjusting the addition amounts of pyridine and acetic anhydride. In Table 1, the tetracarboxylic dianhydrides A to F and the diamines G to M represent the following compounds, respectively.

Acid dianhydride A: The tetracarboxylic acid dianhydride represented by the above formula (2)

Acid dianhydride B: The tetracarboxylic acid dianhydride represented by the above formula (3)

Acid dianhydride C: 2,3,5-tricarboxycyclopentylacetic acid dianhydride

Acid dianhydride D: pyromellitic dianhydride

Acid dianhydride E: 1,2,3,4-Cyclobutane tetracarboxylic acid dianhydride

Acid dianhydride F: 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) c] furan-l, 3-dione

Diamine G: diamine represented by the above formula (17)

Diamine H: p-phenylenediamine

Diamine I: 4,4'-diaminodiphenylmethane

Diamine J: diamine represented by the above formula (15)

Diamine K: The diamine represented by the above formula (27)

Diamine L: diamine represented by the following formula (28)

Diamine M: 2,2'-dimethyl-4,4'-diaminobiphenyl

Example 1

N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether were added to the polymer (P-1) obtained in Synthesis Example 1 at a mixing weight ratio of N-methyl-2-pyrrolidone / ethylene glycol monobutylether = , 20 parts by weight of N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane was added to the polymer (P-1) Thereby forming a liquid crystal aligning agent. However, when the printing test was carried out, a liquid crystal aligning agent having a solid content concentration of 6.5% by weight was used. This was sufficiently stirred, filtered using a filter having a pore size of 0.2 mu m, and applied on a transparent conductive film containing an ITO film provided on one side of the glass substrate, using a spinner. Dried, and then baked at 200 ° C for 1 hour in a clean oven (under a nitrogen atmosphere) to produce a transparent electrode substrate having a liquid crystal alignment film with a thickness of 60 nm. Subsequently, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 占 퐉 was applied to the respective outer edge portions of the pair of transparent electrode / transparent electrode substrates having the liquid crystal alignment film of the liquid crystal alignment film coated substrate so that the liquid crystal alignment film surface faced each other. Polymerized and compressed, and the adhesive was cured. Subsequently, a negative type liquid crystal (MLC-2038, manufactured by Merck & Co., Inc.) was charged between the substrates from the liquid crystal injection port, and then the liquid crystal injection hole was sealed with an acrylic photo-curable adhesive to produce a VA type liquid crystal display device. Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Example 2

A liquid crystal aligning agent and a VA liquid crystal display element of the present invention were obtained in the same manner as in Example 1 except that the polymer (P-2) obtained in Synthesis Example 2 was used instead of the polymer (P-1). Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Example 3

Except that the polymer (P-3) obtained in Synthesis Example 3 was used in place of the polymer (P-1), the solvent composition was N-methyl-2-pyrrolidone / ethylene glycol monobutylether mixture weight ratio = 50 / , N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane was not added to the liquid crystal aligning agent of the present invention and VA type liquid crystal display element . Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Example 4

Except that the polymer (P-4) obtained in Synthesis Example 4 was used in place of the polymer (P-1) and the solvent composition was adjusted to a mixed weight ratio of N-methyl-2-pyrrolidone / ethylene glycol monobutylether = 50 / , And the liquid crystal aligning agent and VA type liquid crystal display device of the present invention were obtained in the same manner as in Example 1. Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Example 5

The polymer (P-5) obtained in Synthesis Example 5 was used in place of the polymer (P-1), and the solvent composition was adjusted to a mixed weight ratio of gamma -butyrolactone / N-methyl-2-pyrrolidone / ethylene glycol monobutylether = / 30/30, the liquid crystal aligning agent and VA type liquid crystal display device of the present invention were obtained in the same manner as in Example 1. [ Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Example 6

(P-6): (P-7) = 50: 50 (weight ratio) instead of the polymer (P-6) obtained in Synthesis Example 6 and the polymer (P- And the solvent composition was changed to a mixed weight ratio of? -Butyrolactone / N-methyl-2-pyrrolidone / ethylene glycol monobutyl ether = 40/35/25, A liquid crystal aligning agent and a VA type liquid crystal display element were obtained. Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Example 7

Butyrolactone and ethylene glycol monobutyl ether were added to the polymer (P-8) obtained in Synthesis Example 8 so that the blend weight ratio of? -Butyrolactone / ethylene glycol monobutyl ether was 90/10, and N, N, 10 parts by weight of N, N'-tetraglycidyl-4,4'-diaminodiphenylmethane was added to the polymer (P-8) to prepare a liquid crystal aligning agent having a solid concentration of 3.5% by weight, And when the printing test was conducted, the liquid crystal aligning agent had a solid concentration of 4.5 wt%). After sufficiently stirring the mixture, the mixture was filtered using a filter having a pore size of 0.2 탆 to prepare a liquid crystal aligning agent of the present invention. The liquid crystal aligning agent of the present invention prepared as described above was applied on a transparent conductive film containing ITO film provided on one side of a glass substrate with a thickness of 1 mm as a comb using a spinner and heated at 180 캜 for 1 hour And dried to form a film having a dry film thickness of 80 nm. A rubbing process was performed using a rubbing machine having a roll coated with a cloth made of nylon formed on the coated film surface to prepare a liquid crystal alignment film. Here, the rubbing treatment conditions were set at a rotation number of 400 rpm of the roll, a moving speed of the stage of 3 cm / sec, and a femoral indentation length of 0.4 mm (this substrate is referred to as a substrate A).

A liquid crystal aligning agent of the present invention prepared as described above was applied to one side of a glass substrate having a thickness of 1 mm using a spinner and dried at 180 DEG C for 1 hour to form a film having a dry film thickness of 80 nm. A rubbing process was performed using a rubbing machine having a roll coated with a cloth made of nylon formed on the coated film surface to prepare a liquid crystal alignment film. Here, the rubbing treatment conditions were set at a rotation speed of 400 rpm of the roll, a moving speed of the stage of 3 cm / sec, and a femoral indentation length of 0.4 mm (this substrate is referred to as substrate B).

An epoxy resin adhesive containing an aluminum oxide sphere having a diameter of 17 mu m was applied to the outer edge of the coated film surface of the substrates A and B by screen printing, and then the two liquid crystal alignment films The substrates were disposed to face each other with a gap therebetween, and the outer edges were brought into contact with each other and pressed to cure the adhesive.

Subsequently, a nematic liquid crystal (MLC-2019, manufactured by Merck & Co., Inc.) was filled between the pair of substrates from the liquid crystal injection port, the liquid crystal injection port was sealed with an epoxy adhesive and the polarizing plate was polarized on both sides of the outside of the substrate Were bonded so as to coincide with the rubbing direction of the liquid crystal alignment film of each substrate, thereby manufacturing an IPS type liquid crystal display device. Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Example 8

The polymer (P-9) obtained in Synthesis Example 9 and the polymer (P-13) obtained in Synthesis Example 13 were mixed so that the ratio of (P-9) :( P-13) = 20: 80 N, N ', N', N'-tetraglycidyl-4,4 ', 5'-tetramethylpiperidone / ethylene glycol monobutyl ether mixed solvent (solvent weight ratio 68/17/15) -Diaminodiphenylmethane was added in an amount of 2 parts by weight based on the total amount of the polymer to prepare a liquid crystal aligning agent having a solid content concentration of 3.5% by weight (provided that when the printing test was conducted, a liquid crystal aligning agent having a solid content concentration of 6.0% box). After sufficiently stirring the mixture, the mixture was filtered using a filter having a pore size of 0.2 탆 to prepare a liquid crystal aligning agent of the present invention. The liquid crystal aligning agent was applied on a transparent conductive film including an ITO film provided on one side of a glass substrate using a spinner, pre-dried at 80 DEG C for 1 minute on a hot plate, Followed by firing for a minute to produce a transparent electrode substrate having a liquid crystal alignment film having a thickness of 60 nm. This film was rubbed once with a rubbing machine having a roll of a rayon cloth wound thereon at a roll rotation speed of 400 rpm, a stage moving speed of 30 mm / sec and a piercing length of 0.4 mm. The liquid crystal alignment film coated substrate was ultrasonically cleaned in pure water for 1 minute and then dried in a clean oven at 100 DEG C for 10 minutes. Subsequently, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 占 퐉 was applied to the outer edge portions of the pair of transparent electrode / transparent electrode substrates having the liquid crystal alignment film of the liquid crystal alignment film coated substrate, and then the liquid crystal alignment film was polished And the adhesive was cured. Subsequently, a nematic liquid crystal (MLC-6221, manufactured by Merck & Co., Inc.) was charged between the substrates from the liquid crystal injection port, the liquid crystal injection port was sealed with an acrylic photocurable adhesive, a polarizing plate was bonded to both sides of the substrate, A display device was manufactured. Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Example 9

The polymer (P-10) obtained in Synthesis Example 10 and the polymer (P-7) obtained in Synthesis Example 7 were used instead of the polymers (P-9) and (P- And N, N ', N'-tetraglycidyl-4,4'-diaminodiphenyl methane was changed to 20 parts by weight based on the whole amount of the polymer, and the solvent composition was changed to γ -Butyrolactone / N-methyl-2-pyrrolidone / ethylene glycol monobutyl ether was 71/17/12, the liquid crystal aligning agent and TN liquid crystal aligning agent of the present invention A display device was obtained. Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Example 10

The polymer (P-11) obtained in Synthesis Example 11 was used in place of the polymer (P-9), and the addition amount of N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane Was changed to 10 parts by weight based on the whole amount of the polymer. The same procedure as in Example 8 was carried out except that the solvent composition was changed to a mixed weight ratio of? -Butyrolactone / N-methyl-2-pyrrolidone / ethylene glycol monobutylether = 72/15 / And a TN type liquid crystal display device were obtained. Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Example 11

The amount of addition of N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane was measured using the polymer (P-12) obtained in Synthesis Example 12 instead of the polymer (P- Except that the solvent was changed to 10 parts by weight based on the total amount of the polymer and the solvent composition was changed to a mixed weight ratio of? -Butyrolactone / N-methyl-2-pyrrolidone / ethylene glycol monobutyl ether = 72/15 / In the same manner, the liquid crystal aligning agent and TN liquid crystal display device of the present invention were obtained. Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Example 12

The polymer (P-14) obtained in Synthesis Example 14 was used in place of the polymer (P-13), and the solvent composition was adjusted to a mixed weight ratio of? -Butyrolactone / N-methyl-2-pyrrolidone / ethylene glycol monobutylether = 72 / 16/12, a liquid crystal aligning agent and a TN type liquid crystal display device of the present invention were obtained in the same manner as in Example 8. Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Comparative Example 1

Except that the polymer (P-15) obtained in Comparative Synthesis Example 1 was used in place of the polymer (P-1) and the solvent composition was N-methyl-2-pyrrolidone / ethylene glycol monobutylether mixed weight ratio = 50 / A liquid crystal aligning agent and a VA type liquid crystal display element were obtained in the same manner as in Example 1 except for the above. Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Comparative Example 2

The polymer (P-16) obtained in Comparative Synthesis Example 2 was used instead of the polymer (P-1), and the solvent composition was changed to a mixed weight ratio of? -Butyrolactone / N-methyl-2-pyrrolidone / ethylene glycol monobutylether = 40/30/30, a liquid crystal aligning agent and a VA type liquid crystal display device were obtained. Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Comparative Example 3

A liquid crystal aligning agent and an IPS liquid crystal display device were obtained in the same manner as in Example 7 except that the polymer (P-17) obtained in Comparative Synthesis Example 3 was used instead of the polymer (P-8). Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Comparative Example 4

A liquid crystal aligning agent and a TN type liquid crystal display device were obtained in the same manner as in Example 8 except that the polymer (P-18) obtained in Comparative Synthesis Example 4 was used instead of the polymer (P-9). Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

Comparative Example 5

A liquid crystal aligning agent and a TN liquid crystal display device were obtained in the same manner as in Example 9 except that the polymer (P-19) obtained in Comparative Synthesis Example 5 was used instead of the polymer (P-10). Table 2 shows the results of evaluating the voltage holding ratio and the reliability of the obtained liquid crystal display element.

From the results of the above Table 2, it is apparent that the liquid crystal alignment films obtained from the liquid crystal aligning agents obtained in Examples 1 to 12 exhibit a higher voltage holding ratio and better reliability than the comparative examples and exhibit excellent liquid crystal aligning agent applicability Do. It is apparent that the above-mentioned characteristics of the liquid crystal aligning agent of the present invention can be adjusted depending on the structure selection and the content of the tetracarboxylic dianhydride represented by the above formula (1).

As described above, according to the present invention, it has been found that it is possible to provide a liquid crystal display device having a liquid crystal aligning agent exhibiting a high voltage holding ratio and excellent in coating properties of a liquid crystal aligning agent and the liquid crystal alignment film and having a beautiful image .

Claims (8)

A polyamic acid obtained by a heavy-chain reaction of a tetracarboxylic acid dianhydride containing at least one aliphatic tetracarboxylic dianhydride represented by the following formula (1) and a diamine containing p-phenylenediamine, and At least one first polymer selected from an imidized polymer obtained by condensation, and A second polymer which is a polyamic acid obtained by a moderate reaction of a tetracarboxylic acid dianhydride and a diamine not containing an aliphatic tetracarboxylic acid dianhydride represented by the following formula Wherein the ratio of the aliphatic tetracarboxylic acid dianhydride represented by the following formula (1) is 5 to 100 mol% based on the total amount of the tetracarboxylic acid dianhydride for synthesizing the first polymer . &Lt; Formula 1 >

(Wherein R ¹ to R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, m is 1, and n is an integer of 0 to 3) delete The liquid crystal aligning agent according to claim 1, wherein the aliphatic tetracarboxylic acid dianhydride represented by the formula (1) is a compound represented by the following formula (3). (3)

The liquid crystal aligning agent according to claim 1 or 3, wherein the diamine for synthesizing the first polymer further comprises a diamine having a pretilt angular expression site represented by the following formula (13). &Lt; Formula 13 >

(Wherein R ⁷ and R ⁸ are each independently a hydrogen atom or a methyl group, R ⁹ is a linear or branched alkyl group having 1 to 20 carbon atoms, and R ¹⁰ and R ¹¹ are each independently a divalent organic group ) The liquid crystal aligning agent according to claim 1 or 3, wherein the diamine for synthesizing the first polymer further comprises a diamine having a pretilt angular expression site represented by the following formula (14). &Lt; Formula 14 >

(Wherein, a is 0 or 1 and R ¹² is an ether bond (-O-), a carbonyl group (-CO-), a carbonyloxy group (-COO-), an oxycarbonyl group (-OCO-) -NHCO-, -CONH-), a thioether bond (-S-) and a methylene group, R ¹³ is a divalent organic group different from R ¹² , and R ¹⁴ is a steroid skeleton A group having a fluorine atom and a group having a straight chain or branched alkyl group having 1 to 30 carbon atoms) The liquid crystal aligning agent according to claim 1 or 3, further comprising at least one epoxy group-containing compound containing two or more epoxy groups in the molecule. A liquid crystal alignment film formed from 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 7.