KR101501779B1 - Liquid crystal aligning agent and liquid crystal display device - Google Patents

Abstract

An object of the present invention is to provide a liquid crystal aligning agent which provides a liquid crystal alignment film exhibiting good liquid crystal alignability and excellent voltage retention and afterimage characteristics, as well as applied to TN type and STN type, as well as vertically aligned type liquid crystal display device.

Wherein the liquid crystal aligning agent is at least one selected from the group consisting of 1,2,3,4-cyclobutane tetracarboxylic dianhydride and tetracarboxylic acid containing 1 to 10 mol% of pyromellitic dianhydride based on the total tetracarboxylic dianhydride At least one polymer selected from the group consisting of a polyamic acid obtained by reacting dianhydride and diamine containing a compound represented by the following formula (1) and an imidized polymer thereof.

A liquid crystal aligning agent, a tetracarboxylic acid dianhydride, a polyamic acid, an imidized polymer

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal aligning agent and a liquid crystal display element,

The present invention relates to a liquid crystal aligning agent and a liquid crystal display element.

More particularly, the present invention relates to a liquid crystal aligning agent which provides a liquid crystal alignment film excellent in voltage retention and afterimage characteristics, and a liquid crystal display element excellent in afterimage characteristics.

At present, as a liquid crystal display element, a liquid crystal alignment film is formed on a substrate surface provided with a transparent conductive film including an ITO (Indium-Tin Oxide) film or the like to form a substrate for a liquid crystal display element, Called Twisted Nematic liquid crystal cell in which a nematic liquid crystal layer having a positive dielectric anisotropy is formed into a cell having a sandwich structure and the major axis of the liquid crystal molecule is twisted by 90 degrees continuously from one substrate toward the other substrate A TN type liquid crystal display device is widely known. Further, a STN (Super Twisted Nematic) type liquid crystal display device which can realize a higher contrast ratio than a TN type liquid crystal display device has been developed. The alignment of liquid crystal molecules in the TN type and STN type liquid crystal display elements is generally controlled by a rubbed liquid crystal alignment film.

On the other hand, a multi-domain vertical alignment (MVA) type liquid crystal display device (see Patent Document 1 and Non-Patent Document 1) is proposed in which protrusions are provided on a transparent conductive film to regulate alignment of liquid crystal molecules to improve viewing angle characteristics. , An EVA (Enhanced Vertical Alignment) type liquid crystal display device (refer to Non-Patent Document 2 below) for performing alignment control of liquid crystal molecules by a special electrode structure, a vertical alignment type liquid crystal display device by a photo alignment method ) Have been proposed in recent years. These vertical alignment type liquid crystal display devices are excellent in viewing angle characteristics, contrast, and the like, and may not be subjected to rubbing treatment in the formation of a liquid crystal alignment film, and are also excellent in manufacturing process. However, the performance is still insufficient as compared with the TN type and STN type liquid crystal display devices described above, and in particular, it is required to improve the vertical alignment property and the performance afterimage characteristic of the liquid crystal display device.

In order to solve the above problems, attention is paid to the relationship between the voltage holding ratio and the afterimage characteristic, and the voltage holding ratio is improved by using a polyimide synthesized by using a diamine compound having an allyl group or an imidized polymer thereof in a liquid crystal alignment film, Attempts have been made to improve the characteristics (see Patent Document 2 below), but the improvement of afterimage characteristics is still insufficient even with this technique.

Further, by using a polyamic acid synthesized using a tetracarboxylic acid dianhydride containing 1,2,3,4-cyclobutane tetracarboxylic dianhydride and pyromellitic dianhydride as a liquid crystal aligning agent, Attempts have been made to improve the voltage holding ratio, residual charge and afterimage characteristics (see Patent Documents 3 to 6 below). However, these techniques have a problem in that a sufficient voltage holding ratio can not be obtained.

[Patent Document 1] JP-A-11-258605

[Patent Document 2] International Publication WO2005 / 052028

[Patent Document 3] Japanese Patent Application No. 2001-206168

[Patent Document 4] Japanese Patent Application Laid-Open No. 2001-510497

[Patent Document 5] Japanese Patent Application Laid-Open No. 2001-296525

[Patent Document 6] Japanese Unexamined Patent Application Publication No. 10-197875

[Patent Document 7] JP-A-6-222366

[Patent Document 8] JP-A-6-281939

[Patent Document 9] JP-A-5-107544

[Non-Patent Document 1] "Liquid Crystal" vol.3 No.2 117 (1999)

[Non-Patent Document 2] "Liquid crystal" vol.3 No.4 272 (1999)

[Non-Patent Document 3] "Jpn Appl. Phys." Vol.36 428 (1997)

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to provide a liquid crystal alignment film which exhibits good liquid crystal alignability as well as application to TN type and STN type, And a liquid crystal display element excellent in residual properties.

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

According to the present invention, said object of the present invention is firstly,

A tetracarboxylic acid dianhydride containing 1 to 10 mol% of pyromellitic dianhydride relative to 1,2,3,4-cyclobutanetetracarboxylic dianhydride and an entire tetracarboxylic dianhydride, And at least one polymer selected from the group consisting of a polyamic acid obtained by reacting a diamine containing a compound represented by the following formula (1) and an imidized polymer thereof.

≪ Formula 1 >

The above object of the present invention is secondly,

And a liquid crystal alignment film formed of the above-mentioned liquid crystal aligning agent.

According to the present invention, it is possible to provide a liquid crystal aligning agent which provides a liquid crystal alignment film exhibiting good liquid crystal alignability, excellent voltage retention and afterimage characteristics, as well as applied to TN type and STN type, An excellent liquid crystal display element can be provided.

<Polyamic acid>

The polyamic acid contained in the liquid crystal aligning agent of the present invention can be obtained by reacting 1,2,3,4-cyclobutane tetracarboxylic dianhydride and the entire tetracarboxylic dianhydride in an amount of 1 to 10 mol% of pyromellitic dianhydride Can be synthesized by reacting a tetracarboxylic acid dianhydride containing a compound represented by the formula (1) with a diamine containing a compound represented by the formula (1).

[Tetracarboxylic acid dianhydride]

The tetracarboxylic acid dianhydride used for synthesizing the polyamic acid contains at least 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride and pyromellitic dianhydride. In the synthesis of the polyamic acid, other tetracarboxylic acid dianhydrides other than 1,2,3,4-cyclobutane tetracarboxylic dianhydride and pyromellitic dianhydride may be used in combination.

Such other tetracarboxylic acid dianhydrides include, for example,

Butane tetracarboxylic acid dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxyl Acid dianhydride, 1,3-dichloro-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracar 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 3,3 ', 4,4'-dicyclopentanetetracarboxylic acid dianhydride, Tricarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 3,5,6-tricarboxy norbornane-2-acetic acid dianhydride, 2,3,4,5-tetra Hydrofuran tetracarboxylic acid dianhydride,

1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2- c] Dione, 1,3,3a, 4,5,9b-hexahydro-5-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [ -1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-ethyl-5- (tetrahydro-2,5-dioxo-3-furanyl) 2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-methyl-5- (tetrahydro- -Naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-ethyl-5- (tetrahydro- 3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro- 1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-ethyl- (Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2- c] -furan- 1,3 -dione, 1,3,3a, 4,5,9b- hexa (Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [l, 2-c] 5-dioxo Cyclohexene-1,2-dicarboxylic acid dianhydride, bicyclo [2,2,2] -oct-7-ene-2,3,5,6-tetrahydro- Tetra-carboxylic acid dianhydride, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 '- (tetrahydrofuran-2', 5'- , 5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 3,5,6-tricarboxy-2-carboxynorbornane- : 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetralone, represented by the formula TI or T-II Aliphatic or alicyclic tetracarboxylic acid dianhydride such as a compound

[Chemical formula I-I]

[Chemical Formula T-II]

(In the formulas TI and T-II, R ¹ and R ³ represent a divalent organic group having an aromatic ring, R ² and R ⁴ represent a hydrogen atom or an alkyl group, and R ² and R ⁴ , Lt; / RTI &gt;

3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylsulfone tetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracar 3,3 ', 4,4'-biphenyl ether tetracarboxylic acid dianhydride, 3,3', 4,4 '-biphenyl ether tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, - dimethyldiphenylsilane tetracarboxylic acid dianhydride, 3,3 ', 4,4'-tetraphenylsilanetetracarboxylic acid dianhydride, 1,2,3,4-furan tetracarboxylic acid dianhydride, 4, 4,4'-bis (3,4-dicarboxyphenoxy) diphenyl sulfone dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfide dianhydride, 3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ', 4,4'-perfluoroisopropylidene diphthalic acid dianhydride, 3,3', 4,4'-biphenyltetracar Bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphosphine) diisocyanate, 2,2 ', 3,3'-biphenyltetracarboxylic dianhydride, (Triphenylphthalic acid) -4,4'-di (triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis Propylene glycol-bis (anhydrotrimellitate), 1,4-butanediol-bis (anhydrotrimellitate), 1,6-hexanediol Bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate), 1,8-octanediol-bis (anhydrotrimellitate) Aromatic tetracarboxylic acid dianhydrides such as compounds represented by the formulas T-1 to T-4. These may be used singly or in combination of two or more.

[Chemical formula (T-1)

[Chemical Formula T-2]

[Chemical Formula T-3]

[Chemical Formula T-4]

Of these, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro- 1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5,8-dimethyl-5- (tetrahydro- -Dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, bicyclo [2,2,2] - tetracarboxylic dianhydride, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3'- (tetrahydrofuran-2 ', 5'- 3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 3,5,6-tricarboxy-2-carboxy norbornane- 2: 3,5: 6-dianhydride, 4, Dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, 3,3 ', 4,4'-benzophenonetetracarboxylic acid dianhydride, 3,3 ', 4,4'-biphenylsulfonetetracarboxylic acid dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride Water, a compound represented by the following general formula T-5 to T-7 and a compound represented by the general formula T-II in the compound represented by the general formula TI, and a compound represented by the following general formula T-8 to exhibit good liquid crystal alignability . Another particularly preferred tetracarboxylic dianhydride is 2,3,5-tricarboxycyclopentylacetic dianhydride.

[Chemical Formula T-5]

[Chemical Formula T-6]

[Chemical Formula T-7]

[Chemical Formula T-8]

The tetracarboxylic acid dianhydride used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention is obtained by reacting 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride with the total tetracarboxylic acid dianhydride , Preferably 60 to 99 mol%, more preferably 65 to 97 mol%. Further, pyromellitic dianhydride is contained in an amount of 1 to 10 mol% based on the total tetracarboxylic dianhydride, but this value is preferably 2 to 10 mol%.

The tetracarboxylic acid dianhydride used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention may further contain 2,3,5-tricarboxycyclopentylacetic dianhydride as the other tetracarboxylic dianhydride Is preferably contained in an amount of 50 mol% or less, more preferably 10 mol% to 40 mol%, and still more preferably 15 mol% to 35 mol%, based on the tetracarboxylic acid dianhydride.

By using the tetracarboxylic dianhydride containing the respective tetracarboxylic dianhydrides in the respective ratios as described above, it is possible to obtain a polymer exhibiting good solubility with respect to the solvent to be described later, and a polymer formed by a liquid crystal aligning agent containing the same The liquid crystal alignment film is preferable in that the alignment property is excellent.

[Diamine]

The diamine used for synthesizing the polyamic acid contains the compound represented by the formula (1). In the synthesis of the polyamic acid, diamines other than the diamine may be used in combination.

Examples of such other diamines include diamines having a steroid skeleton and other diamines.

Examples of the diamine having a steroid skeleton include a compound represented by the following formula (D-I) and a compound represented by the following formula (D-II). Specific examples thereof include compounds represented by the following formulas (D-1) to (D-6);

[Formula D-I]

(In the formula DI, X ¹ represents a divalent organic group selected from -O-, -COO-, -OCO-, -NHCO-, -CONH- and -CO-, R ⁵ represents a monovalent organic group having a steroid skeleton Lt; / RTI &gt;

[Formula D-II]

(In the formula (D-II), X ² represents a divalent organic group selected from -O-, -COO-, -OCO-, -NHCO-, -CONH- and -CO-, and R ⁶ represents a divalent organic group having 2 &Lt; / RTI &gt;

[Formula D-1]

[Formula D-2]

[Formula D-3]

[Formula D-4]

[Formula D-5]

[Formula D-6]

Examples of the compound represented by the above formula (D-II) include compounds represented by the following formulas (D-7) to (D-9).

[Formula D-7]

[Formula D-8]

[Chemical formula D-9]

As the other diamines, for example,

p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylsulfide, 4,4 ' Diaminodiphenylsulfone, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether, 1,5-di Diminaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-ditrifluoromethyl- Diaminobiphenyl, 3,3'-ditrifluoromethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl) -1,3,3-trimethyl (4'-aminophenyl) -1,3,3-trimethylindane, 3,4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) Phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis [4- Benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, Diaminofluorene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, 2,7-diaminofluorene, Fluorene, 4,4'-methylene-bis (2-chloroaniline), 2,2 ', 5,5'-tetrachloro-4,4'- diaminobiphenyl, 2,2'- , 4'-diamino-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 1,4,4 '- (p- phenyleneisopropylidene ) Bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane (hereinafter referred to as &quot; , 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl, 4,4'-bis [(4-amino-2- trifluoromethyl) phenoxy] -octafluoroborane Aromatic diamines such as phenyl;

But are not limited to, 1,1-hexanediol diamine, 1,1-meta-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, , 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindenyldimethylenediamine, tricyclo [6.2.1.0 ^2,7 ] undecylene Aliphatic or alicyclic diamines such as dimethyldiamine, 4,4'-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane and 1,4-bis (aminomethyl) cyclohexane;

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, Aminophenyl) phenylamine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl- Aminocarbazole, N-phenyl-3,6-diaminocarbazole, N, N'-di (4-aminophenyl) -benzidine, a compound represented by the following formula D-III, A diamine having two primary amino groups in the molecule such as a compound and a nitrogen atom other than the primary amino group;

[Formula D-III]

(In the formula (D-III), R ⁷ represents a monovalent organic group having a ring structure including a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, and X ³ represents a divalent organic group )

[Formula D-IV]

(In the formula (D-IV), R ⁸ represents a divalent organic group having a ring structure including a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, and X ⁴ represents a divalent organic group And a plurality of X &lt; ⁴ &gt; s may be the same or different,

A compound represented by the following formula (D-V);

[Chemical formula D-V]

(In the formula (IV), X ⁵ represents a divalent organic group selected from -O-, -COO-, -OCO-, -NHCO-, -CONH- and -CO-, and R ⁹ represents a monovalent organic group having a fluorine atom Or an alkyl group having 6 to 30 carbon atoms)

A compound represented by the following formula (D-VI);

[Formula D-VI]

(Wherein R ¹⁰ represents a hydrocarbon group of 1 to 12 carbon atoms, plural R ^{10 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)

A compound represented by the following formula (D-10) or (D-11), and the like. These diamines may be used alone or in combination of two or more.

[Formula D-10]

[Formula D-11]

(Y in the formula (D-10) is an integer of 2 to 12, and z in the formula (D-11) is an integer of 1 to 5)

Of these, diamines having a steroid skeleton, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 1,5-diaminonaphthalene, 2,2'- Dimethyl-4,4'-diaminobiphenyl, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 2,7-diaminofluorene, 4,4'- Phenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9- ) Phenyl hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '- (p-phenylenediisopropylidene) 4,4'-bis (4-aminophenoxy) biphenyl, 1,4-cyclohexanediamine, 4,4'- -Methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, Diami Acridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N- Among the compounds represented by the above formula (D-III), the compounds represented by the following formula (D-12) and the compounds represented by the formula (D-IV) -13, dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene , Octadecanoxy-2,4-diaminobenzene, dodecaneoxy-2,5-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-diaminobenzene, octa Decanoxy-2,5-diaminobenzene, a compound represented by the following formula (D-14) to (D-16) or a compound represented by the formula (D-VI) Siloxane is preferred The.

[Formula D-12]

[Formula D-13]

[Chemical Formula D-14]

[Formula D-15]

[Formula D-16]

Particularly preferred other diamines are diamines having a steroid skeleton, of which the compounds represented by the above formulas D-I or D-II are preferred.

The diamine used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention is preferably at least 30 mol%, more preferably from 40 to 80 mol%, based on the total diamine, of the compound represented by the formula (1) More preferably 50 to 75 mol%. The diamine used for synthesizing the polyamic acid preferably contains 50 mol% or less, more preferably 10 to 30 mol%, of the diamine having a steroid skeleton based on the total diamine.

It is preferable to use a diamine containing each of the diamines in the above-mentioned ratio in order to obtain a liquid crystal aligning agent which provides a liquid crystal alignment film excellent in voltage retention and afterimage characteristics.

[Synthesis of polyamic acid]

The polyamic acid which may be contained in the liquid crystal aligning agent of the present invention is preferably 1 to 10 mol% of pyromellitic acid relative to 1,2,3,4-cyclobutane tetracarboxylic dianhydride and the entire tetracarboxylic dianhydride Is obtained by reacting a tetracarboxylic acid dianhydride containing dianhydride with a diamine containing the compound represented by the formula (1).

The ratio of the tetracarboxylic dianhydride and the diamine used in the synthesis reaction of the polyamic acid is preferably such that the amount of the acid anhydride group of the tetracarboxylic dianhydride is 0.5 to 2 equivalents based on 1 equivalent of the amino group of the diamine, Is 0.7 to 1.2 equivalents.

The synthesis reaction of the polyamic acid is preferably carried out in an organic solvent under a temperature condition of preferably -20 ° C to 150 ° C, more preferably 0 to 100 ° C, preferably 1 to 48 hours, more preferably 2 For 12 hours. The organic solvent is not particularly limited as long as it can dissolve the polyamic acid to be produced, and examples thereof include 1-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, Amide compounds such as butoxy-N, N-dimethylpropanamide, 3-methoxy-N, N-dimethylpropanamide and 3-hexyloxy-N, N-dimethylpropanamide, dimethylsulfoxide, Amphoteric compounds such as lactone, tetramethyl urea, and hexamethylphosphoric triamide; phenol compounds such as m-cresol, xylenol, phenol, halogenated phenol, and the like. The amount (a) of the organic solvent used is preferably such that the total amount (b) of the tetracarboxylic acid dianhydride and the diamine compound is 0.1 to 30% by weight based on the total amount (a + b) of the reaction solution.

Alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbon, etc., which are poor solvents of polyamic acid, may be added to the organic solvent in such a range that the produced polyamic acid is not precipitated. Specific examples of such a poor solvent include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol, propylene glycol, But are not limited to, triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, Propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether, ethylene glycol diisopropyl ether, diethylene glycol diethyl ether, diethylene glycol diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol- , Ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol Monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloro There may be mentioned ethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, diisobutylketone, isoamylpropionate, isoamylisobutyrate and diisopentylether.

When an organic solvent and a poor solvent are used in combination, the amount of the poor solvent to be used can be suitably determined within a range in which the produced polyamic acid is not precipitated, but is preferably 30% by weight or less based on the total amount of the solvent, desirable.

In this way, a reaction solution obtained by dissolving polyamic acid is obtained. The reaction solution may be used as it is for preparing a liquid crystal aligning agent. Alternatively, the polyamic acid contained in the reaction solution may be isolated and used for the preparation of a liquid crystal aligning agent, or after the isolated polyamic acid is purified, . The isolation of the polyamic acid can be carried out by pouring the reaction solution into a large amount of poor solvent to obtain a precipitate and drying the precipitate under reduced pressure, or by a method of distilling off the reaction solution under reduced pressure using an evaporator. Alternatively, the polyamic acid can be purified by a method of dissolving the polyamic acid in an organic solvent and then precipitating it with a poor solvent, or a step of distillation under reduced pressure using an evaporator once or several times.

<Imidized Polymer>

The imidized polymer that may be contained in the liquid crystal aligning agent of the present invention can be obtained by imidizing the polyamic acid as described above by dehydrating and ring closure.

Examples of the tetracarboxylic acid dianhydride used in the synthesis of the imidized polymer include the same compounds as the tetracarboxylic dianhydride used in the synthesis of the polyamic acid described above. Examples of the diamine used for synthesizing the imidized polymer contained in the liquid crystal aligning agent of the present invention include the same diamine as the diamine compound used in the synthesis of the above-mentioned polyamic acid.

The imidized polymer contained in the liquid crystal aligning agent of the present invention may be a completely imidized product in which all of the amic acid structure possessed by the raw material polyamic acid is dehydrated and cyclized and only a part of the amic acid structure is dehydrated and cyclized to form an amic acid structure And the moiety in which the imidazole ring structure coexists may be a midtones.

The imidized polymer contained in the liquid crystal aligning agent of the present invention preferably has an imidization ratio of 60% or more, more preferably 70% or more, and further preferably 80% or more. By using an imidized polymer having an imidization ratio of 60% or more, it is possible to obtain a liquid crystal aligning agent capable of forming an excellent liquid crystal alignment film by the afterimage characteristic.

The imidization ratio is expressed as a percentage of the ratio of the number of imide ring structures to the sum of the number of amic acid structures and the number of imide ring structures in the imidized polymer. At this time, a part of the imide ring may be an isoimide ring. The imidation rate can be determined by dissolving the imidized polymer in a suitable deuterated solvent (for example, deuterated dimethyl sulfoxide) and measuring tetramethylsilane as a reference material at room temperature by ¹ H-NMR, . &Lt; / RTI &gt;

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

(A ¹ is the peak area derived from the proton of the NH group near 10 ppm of the chemical shift, A ² is the peak area derived from the other protons, and? Is the precursor of the imidized polymer (polyamic acid) The ratio of the number of other protons to one of the proton of the NH group in the &lt; RTI ID = 0.0 &gt;

The dehydration ring-closure of the polyamic acid is preferably carried out by heating the polyamic acid (i), or (ii) dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to the solution, . &Lt; / RTI &gt;

The reaction temperature in the method of heating the polyamic acid of (i) is preferably 50 to 200 占 폚, more preferably 60 to 170 占 폚. The reaction time is preferably 1 to 120 hours, more preferably 2 to 48 hours. If the reaction temperature is less than 50 ° C, the dehydration ring-closure reaction does not proceed sufficiently, and if the reaction temperature exceeds 200 ° 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 dehydrating 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. The amount of the dehydrating agent used is preferably 0.01 to 20 mol based on 1 mol of the amic acid structure of the polyamic acid although it differs depending on the desired imidization ratio. As the dehydration cyclization catalyst, for example, tertiary amines such as pyridine, collidine, lutidine and triethylamine can be used. However, it is not limited thereto. 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 imidization rate can be increased as the amount of the dehydrating agent and the dehydrating ring closure agent used is larger. Examples of the organic solvent used in the dehydration ring-closure reaction include organic solvents exemplified for use in the synthesis of polyamic acid. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C, more preferably 10 to 150 ° C. The reaction time is preferably 1 to 24 hours, more preferably 2 to 8 hours.

In the above method (ii), a reaction solution containing the imidized polymer is obtained as described above. This reaction solution can be used as it is for the preparation of a liquid crystal aligning agent or after the dehydrating agent and the dehydration ring-closing catalyst are removed from the reaction solution, the reaction solution can be used for preparing a liquid crystal aligning agent or after the imidized polymer is isolated, Or may be used in the production of a liquid crystal aligning agent after purification of the isolated imidized polymer. In order to remove the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution, for example, a method such as solvent substitution can be applied. Isolation and purification of the imidized polymer can be performed by carrying out the same operation as described above as a method for isolation and purification of polyamic acid.

- Polymers of terminal modified type -

The polyamic acid or imidized polymer contained in 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 modified type, the coating property and the like of the liquid crystal aligning agent can be further improved without impairing the effect of the present invention. Such a terminal modified polymer can be produced by adding a molecular weight regulator to a polymerization reaction system when synthesizing a polyamic acid. Examples of the molecular weight regulator include acid monoanhydrides, monoamine compounds, and monoisocyanate compounds.

Examples of the acid anhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride and n-hexadecylsuccinic anhydride. have. Examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, hexadecylamine, n-heptadecylamine, n-octadecylamine, n-octadecylamine, n-octadecylamine, Eicosylamine 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 the tetracarboxylic acid dianhydride and diamine used in synthesizing the polyamic acid.

- solution viscosity -

The polyamic acid or the imidized polymer obtained as described above preferably has a solution viscosity of 20 to 800 mPa 으로 when it is a 10 wt% solution and has a solution viscosity of 30 to 500 mPa 보다 desirable.

The solution viscosity (mPa 占 퐏) of the polymer was determined by using an E-type rotational viscometer at 25 (concentration) of a polymer solution having a concentration of 10% by weight prepared by using a good solvent for the polymer (e.g.,? -Butyrolactone) Lt; 0 &gt; C.

<Other additives>

The liquid crystal alignment film of the present invention contains at least one polymer selected from the group consisting of the above-mentioned polyamic acid and its imidized polymer. The polymer contained in the liquid crystal aligning agent of the present invention is preferably an imidized polymer.

The liquid crystal alignment film of the present invention contains the polymer as described above as an essential component, but may contain other components as necessary. Such other components include, for example, a compound having two or more epoxy groups in the molecule (hereinafter referred to as "epoxy compound") and a functional silane compound.

Examples of the epoxy compound 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, 1,3,5, Tetraglycidyl-2,4-hexanediol, N, N, N ', N'-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl ) N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 3- (N-allyl-N-glycidyl) aminopropyltrimethoxysilane, And 3- (N, N-diglycidyl) aminopropyltrimethoxysilane.

The proportion of the epoxy compound as described above is preferably 40 parts by weight or less based on 100 parts by weight of the total amount of the polymer (the total amount of the polyamic acid and the imidized polymer contained in the liquid crystal aligning agent) 0.1 to 30 parts by weight.

Examples of the 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, N-bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane and the like.

The use ratio of the functional silane compound as described above is preferably 2 parts by weight or less, more preferably 0.2 parts by weight or less, based on 100 parts by weight of the total amount of the polymer.

<Liquid Crystal Aligner>

The liquid crystal aligning agent of the present invention is constituted by dissolving and containing at least one member selected from the group consisting of the above-mentioned polyamic acid and its imidized polymer and optionally other additives optionally mixed in an organic solvent .

Examples of the organic solvent include the solvents exemplified for use in the synthesis reaction of polyamic acid. The poor solvent exemplified as being usable in the synthesis reaction of the polyamic acid can also be suitably selected and used in combination.

Examples of particularly preferable organic solvents used in the liquid crystal aligning agent of the present invention include N-methyl-2-pyrrolidone,? -Butyrolactone,? -Butyrolactam, N, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, , Ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, Dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether There may be mentioned the lactate, isoamyl propionate, isoamyl isobutyrate, di-isopentyl ether. These may be used alone or in combination of two or more.

The solid concentration in the liquid crystal aligning agent of the present invention (the ratio of the total weight of components other than the solvent of the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc., 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 preferably is heated to form a coating film which becomes a liquid crystal alignment film. However, when the solid concentration is less than 1% by weight, On the other hand, 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, the viscosity of the liquid crystal aligning agent is increased, and the coating property is deteriorated .

Particularly preferable range of the solid concentration varies depending on the method used when applying the liquid crystal aligning agent 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 that the solid concentration is in the range of 3 to 9% by weight and the solution viscosity is 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 for producing the liquid crystal aligning agent of the present invention is preferably 0 to 200 캜, more preferably 20 to 60 캜.

<Liquid crystal display element>

The liquid crystal display element of the present invention comprises the liquid crystal alignment layer formed of the liquid crystal aligning agent of the present invention as described above.

The liquid crystal display element of the present invention can be produced, for example, by the following steps (1) to (3).

(1) First, two pairs of substrates on which a patterned transparent conductive film is provided are placed on each transparent conductive film-formed surface, and the liquid crystal aligning agent of the present invention is laminated on the respective transparent conductive film forming surfaces by a roll coater method, a spinner method, A coating method, a printing method, or the like, and then each coating surface is heated to form a coating film. 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 poly (alicyclic olefin) can be used. As the transparent conductive film to be provided on one surface 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 ) In order to obtain a patterned transparent conductive film, for example, a method of forming a transparent conductive film without a pattern and then forming a pattern by photo-etching, a method of using a mask having a desired pattern when forming a transparent conductive film And the like. In order to improve the adhesiveness between the substrate surface and the transparent conductive film and the coating film during the application of the liquid crystal aligning agent, the surface of the substrate surface on which the coating film is to be formed may be pre-applied with a functional silane compound, a functional titanium compound, Processing may be performed.

The heating temperature after application of the liquid crystal aligning agent is preferably 30 to 300 占 폚, more preferably 40 to 250 占 폚, and the heating time is preferably 1 to 30 minutes, more preferably 5 to 20 minutes. 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) Then, the coating film surface formed as described above is rubbed in a predetermined direction with a cloth-wound roll including fibers such as nylon, rayon, and cotton. Accordingly, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film. In addition, the vertically aligned liquid crystal display element may not be subjected to the rubbing treatment. In this case, the above coating film can be used as it is as a liquid crystal alignment film.

Further, the liquid crystal alignment film formed by the liquid crystal aligning agent of the present invention can be produced, for example, in Patent Document 7 (Japanese Patent Application Laid-Open No. 6-222366) or Patent Document 8 (Japanese Patent Application Laid-Open No. 6-281939 (Japanese Unexamined Patent Publication (Kokai) No. 5-107544) discloses a treatment for changing a pretilt angle of a part of a liquid crystal alignment film by irradiating a part of the liquid crystal alignment film as described in Patent Document 9 A process of forming a resist film on a part of the surface of the liquid crystal alignment film as described above and then rubbing treatment in a direction different from the rubbing process performed previously is performed to remove the resist film to obtain a liquid crystal alignment film having a liquid crystal aligning ability different from region to region, It is possible to improve the visual field characteristic of the display element.

(3) A pair of substrates on which a liquid crystal alignment film is formed as described above is disposed opposite to each other through a gap (cell gap) such that the rubbing directions of the liquid crystal alignment films of the two substrates are orthogonal or inverted, The periphery of the substrate is bonded using a sealant, 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. Further, a liquid crystal display element can be obtained by joining the polarizing plate on the outer surface of the liquid crystal cell so that its polarization direction coincides with or perpendicular to the rubbing direction of the liquid crystal alignment film formed on each substrate. 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 the liquid crystal include a nematic liquid crystal and a smectic liquid crystal. Among them, a nematic liquid crystal is preferable. Examples thereof include a liquid crystal such as a Schiff salt mechanical liquid crystal, an agglomerated clock liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, , Terphenyl-based liquid crystals, biphenylcyclohexane-based liquid crystals, pyrimidine-based liquid crystals, dioxane-based liquid crystals, bicyclooctane-based liquid crystals, quaternary-based liquid crystals and the like. Examples of the liquid crystal include cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonoate and cholesteryl carbonate; Chiral agents sold under the trade names "C-15" and "CB-15" (manufactured by Merck); and a ferroelectric liquid crystal such as p-disiloxybenzylidene-p-amino-2-methylbutyl cinnamate.

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 made of H film itself is exemplified.

<Examples>

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples.

The imidization ratio of the imidized polymer in the following synthesis examples was measured by a method in which the imidized polymer was sufficiently dried under reduced pressure at room temperature and then dissolved in deuterated dimethyl sulfoxide and tetramethylsilane was used as a reference material and ¹ H -NMR according to Equation (1) above.

Synthesis Example 1

93 g (0.48 mol) of 1,2,3,4-cyclobutane tetracarboxylic dianhydride and 5 g (0.03 mol) of pyromellitic dianhydride as a tetracarboxylic dianhydride, 2,4-diamine 81 g (0.4 mol) of minino-N, N-diallyaniline (the compound represented by the formula 1) and 52 g (0.1 mol) of the compound represented by the formula D-3 were dissolved in N-methyl- And the reaction was carried out at 60 DEG C for 6 hours to obtain a solution containing polyamic acid. A small amount of the obtained polyamic acid solution was collected and N-methyl-2-pyrrolidone was added to measure the solution viscosity as a solution having a polyamic acid concentration of 10% by weight, and found to be 53 mPa.s.

Next, 1,160 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, and 198 g of pyridine and 204 g of acetic anhydride were added, followed by dehydration ring-closure reaction at 110 ° C for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with a new? -Butyrolactone solvent (pyridine and acetic anhydride used in the dehydration ring closure imidization reaction were removed from the system by this operation) to obtain imidized About 1,300 g of a solution containing the polymer (A-1) was obtained. A small amount of the imidized polymer solution was collected, and? -Butyrolactone was added to measure the solution viscosity as a solution having an imidized polymer concentration of 10% by weight, and found to be 65 mPa 占 퐏.

Synthesis Example 2

93 g (0.48 mol) of 1,2,3,4-cyclobutane tetracarboxylic dianhydride and 5 g (0.03 mol) of pyromellitic dianhydride as a tetracarboxylic dianhydride, 2,4-diamine (0.2 mol) of mono-N, N-diallyaniline (61 g, 0.3 mol) and 4- [4- (4- trans- n-heptylcyclohexyl) phenoxy] Was dissolved in 944 g of N-methyl-2-pyrrolidone and reacted at 60 DEG C for 6 hours to obtain a solution containing polyamic acid. A small amount of the obtained polyamic acid solution was collected and N-methyl-2-pyrrolidone was added to measure the solution viscosity as a solution having a polyamic acid concentration of 10% by weight, and found to be 56 mPa 占 퐏.

Subsequently, 1,180 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, and 198 g of pyridine and 204 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 new? -Butyrolactone solvent (pyridine and acetic anhydride used in this dehydration ring-closure reaction were removed from the system by this operation) to obtain an imidized polymer having an imidization rate of about 94% A-2). &Lt; / RTI &gt; A small amount of this imidized polymer solution was collected, and? -Butyrolactone was added to measure the solution viscosity as a solution having an imidized polymer concentration of 10% by weight, and found to be 67 mPa.s.

Synthesis Example 3

64 g (0.33 mol) of 1,2,3,4-cyclobutane tetracarboxylic dianhydride as a tetracarboxylic dianhydride, 34 g (0.15 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride and 5 g (0.03 mol) of pyromellitic dianhydride, 81 g (0.4 mol) of 2,4-diamino-N, N-diallylaniline as a diamine compound and 52 g ) Was dissolved in 956 g of N-methyl-2-pyrrolidone, and the reaction was carried out at 60 DEG C for 6 hours to obtain a solution containing polyamic acid. A small amount of the obtained polyamic acid solution was fractionated and N-methyl-2-pyrrolidone was added to measure the solution viscosity as a solution having a polyamic acid concentration of 10% by weight, and found to be 52 mPa.s.

Next, 1,195 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, and 198 g of pyridine and 204 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 cyclization reaction, the solvent in the system was replaced with a new? -Butyrolactone solvent (pyridine and acetic anhydride used in this dehydration cyclization reaction were removed from the system by this operation) to obtain imidized About 1,300 g of a solution containing the polymer (A-3) was obtained. A small amount of this imidized polymer solution was collected and? -Butyrolactone was added to measure the solution viscosity as a solution having an imidized polymer concentration of 10% by weight, and found to be 63 mPa 占 퐏.

Comparative Synthesis Example 1

98 g (0.5 mol) of 1,2,3,4-cyclobutane tetracarboxylic dianhydride as a tetracarboxylic dianhydride and 81 g of 2,4-diamino-N, N-diallylamine as a diamine compound 0.4 mol) and 52 g (0.1 mol) of the compound represented by the above formula (D-3) were dissolved in 926 g of N-methyl-2-pyrrolidone and reacted at 60 DEG C for 6 hours to obtain a solution &Lt; / RTI &gt; A small amount of the obtained polyamic acid solution was fractionated and N-methyl-2-pyrrolidone was added to measure the solution viscosity as a solution having a polyamic acid concentration of 10% by weight, and found to be 52 mPa.s.

Next, 1,158 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, and 198 g of pyridine and 204 g of acetic anhydride were added, followed by dehydration ring-closure reaction at 110 ° C for 4 hours. After the dehydration cyclization reaction, the solvent in the system was replaced with a new? -Butyrolactone solvent (pyridine and acetic anhydride used in this dehydration cyclization reaction were removed from the system by this operation) to obtain an imidization rate of about 93% About 1,300 g of a solution containing the hydrogenated polymer (B-1) was obtained. A small amount of this imidized polymer solution was collected, and? -Butyrolactone was added thereto to measure the solution viscosity as a solution having an imidized polymer concentration of 10% by weight, and found to be 62 mPa 占 퐏.

Comparative Synthesis Example 2

98 g (0.5 mole) of 1,2,3,4-cyclobutane tetracarboxylic dianhydride as a tetracarboxylic dianhydride and 61 g of 2,4-diamino-N, N-diallylamine as a diamine compound (0.2 mol) of 4- [4- (4- trans-n-heptylcyclohexyl) phenoxy] -1,3-diaminobenzene was dissolved in 941 g of N-methyl- And the reaction was carried out at 60 DEG C for 6 hours to obtain a solution containing polyamic acid. A small amount of the obtained polyamic acid solution was collected and N-methyl-2-pyrrolidone was added to measure the solution viscosity as a solution having a polyamic acid concentration of 10% by weight, and found to be 48 mPa.s.

Then, 1,177 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, and 198 g of pyridine and 204 g of acetic anhydride were added, followed by dehydration ring closure reaction at 110 ° C for 4 hours. After the dehydration cyclization reaction, the solvent in the system was replaced with a new? -Butyrolactone solvent (pyridine and acetic anhydride used in this dehydration cyclization reaction were removed from the system by this operation) to obtain imidized About 1,300 g of a solution containing the polymer (B-2) was obtained. A small amount of the imidized polymer solution was collected, and? -Butyrolactone was added to measure the solution viscosity as a solution having an imidized polymer concentration of 10% by weight, which was 55 mPa 占 퐏.

Comparative Synthesis Example 3

As the tetracarboxylic acid dianhydride, 93 g (0.5 mol) of 1,2,3,4-cyclobutane tetracarboxylic dianhydride and 5 g (0.03 mol) of pyromellitic dianhydride as the diamine compound, 4,4'- 80 g (0.4 mol) of diaminodiphenyl ether and 52 g (0.1 mol) of the compound represented by the above formula (D-3) were dissolved in 944 g of N-methyl-2-pyrrolidone and reacted at 60 DEG C for 6 hours To obtain a solution containing polyamic acid. A small amount of the obtained polyamic acid solution was fractionated and N-methyl-2-pyrrolidone was added to measure the solution viscosity as a solution having a polyamic acid concentration of 10% by weight, and found to be 52 mPa.s.

Next, 924 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, and 198 g of pyridine and 204 g of acetic anhydride were added and the dehydration ring-closure reaction was carried out at 110 DEG C for 4 hours, Precipitation. Since this gel polymer was not dissolved in both N-methyl-2-pyrrolidone and? -Butyrolactone, subsequent analysis and evaluation were not carried out.

Example 1

&Lt; Preparation of liquid crystal aligning agent &

(BL), N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) were added to a solution containing the imidized polymer (A-1) obtained in Synthesis Example 1 To prepare a solution having a solvent composition of BL: NMP: BC = 71: 17: 12 (weight ratio) and a solid concentration of 4% by weight, and this solution was filtered using a filter having an opening diameter of 1 占 퐉 to prepare a liquid crystal aligning agent.

&Lt; Evaluation of voltage holding ratio &

The liquid crystal aligning agent prepared above was applied to the transparent electrode surface of the glass substrate with a transparent electrode including the ITO film using a liquid crystal alignment film printing machine (manufactured by Nippon Sha Shingen Co., Ltd.) and heated on a hot plate at 80 캜 for 1 minute And further heated on a hot plate at 200 DEG C for 10 minutes to form a coating film having an average film thickness of 600 ANGSTROM. This operation was repeated to prepare two substrates (one pair) having a coating film. The coating film on these substrates was observed under a microscope with a magnification of 20 times, and no printing irregularity or pinholes were observed, and the coating properties were good.

An epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 mu m was applied to each of the outer edges of the coated film-attached substrates having a pair of liquid crystal alignment films, and the adhesive liquid was superimposed and bonded so that the liquid crystal alignment film surfaces faced each other. Subsequently, a negative type liquid crystal (MLC-2038, manufactured by Merck & Co., Inc.) was filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection hole was sealed with an acrylic photo-curing adhesive to prepare a liquid crystal cell for evaluating the voltage holding ratio .

A voltage of 5 V was applied to the liquid crystal cell at an environmental temperature of 60 占 폚 with a span of 167 milliseconds after the application time of 60 microseconds and then the voltage maintenance ratio after 167 milliseconds from the application of the liquid crystal cell was measured. VHR-1 manufactured by Toyo Technica Co., Ltd. was used as a measuring device. The voltage holding ratio was evaluated as "good" when the voltage holding ratio was 95% or more, and the voltage holding ratio was rated "bad"

&Lt; Evaluation of after-image characteristic &

A liquid crystal cell for evaluating afterimage characteristics was prepared in accordance with the method described in < evaluation of voltage holding ratio > except that a substrate having an ITO electrode as shown in Fig. 1 was used as a substrate. A DC voltage of 6.0 V was applied to the electrode (A), and a DC voltage of 0.5 V was applied to the electrode (B) at room temperature for 24 hours. After the voltage was removed, the luminance difference in the areas corresponding to the electrodes (A) and (B) when the direct current voltage of 0.1 to 5.0 V was applied to the electrodes (A) and (B) by 0.1 V was evaluated. When the luminance difference was small, the afterimage characteristic was evaluated as "good" and when the luminance difference was large, the afterimage characteristic was evaluated as "bad ".

Examples 2 and 3, Comparative Examples 1 and 2

A liquid crystal aligning agent was prepared and evaluated in the same manner as in Example 1 except that a solution containing the polymer described in the following Table 1 was used instead of the solution containing the imidized polymer (A-1). The evaluation results are shown in Table 1 below.

1 is a schematic view of a liquid crystal cell manufactured for evaluation of afterimage characteristics.

Claims (5)

A tetracarboxylic acid dianhydride containing 1 to 10 mol% of pyromellitic dianhydride relative to 1,2,3,4-cyclobutanetetracarboxylic dianhydride and an entire tetracarboxylic dianhydride, And a diamine containing diamine having a steroid skeleton in an amount of 10 to 50 mol% based on the total diamine, and an imidized polymer thereof, wherein the polyamic acid is at least one selected from the group consisting of A liquid crystal aligning agent characterized by being used for forming a liquid crystal alignment film of an alignment type liquid crystal display element. &Lt; Formula 1 >

The liquid crystal aligning agent according to claim 1, wherein the tetracarboxylic dianhydride further contains 2,3,5-tricarboxycyclopentylacetic dianhydride. The liquid crystal aligning agent according to claim 1, further comprising a compound having two or more epoxy groups in the molecule. A method of forming a liquid crystal alignment film of a vertically aligned liquid crystal display element in which a liquid crystal aligning agent according to any one of claims 1 to 3 is applied on a substrate to form a coated film and subsequently the coated film is heated, Is not subjected to rubbing treatment. A vertical alignment type liquid crystal display device comprising a liquid crystal alignment film formed from the liquid crystal alignment agent according to any one of claims 1 to 3 without rubbing treatment.

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