KR101431277B1 - Liquid crystal aligning agent and liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal aligning agent containing at least one polymer selected from the group consisting of polyamic acid and polyimide obtained by dehydration cyclization thereof and a solvent, wherein the solvent is (A) a compound represented by the following formula (I) (B) at least one solvent selected from the group consisting of N-methyl-2-pyrrolidone,? -Butyrolactone, 1,3-dimethyl-2-imidazolidinone, Dimethylacetamide, and (C) at least one solvent selected from the group consisting of butyl cellosolve, diacetone alcohol, propylene carbonate, diethylene glycol diethyl ether and ethyl-3-ethoxy And a third solvent comprising at least one member selected from the group consisting of propionate.

(Wherein each R is independently an alkyl group having from 3 to 10 carbon atoms)

Liquid crystal aligning agent, liquid crystal display element

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 having good applicability and excellent various performances such as liquid crystal aligning ability in an inkjet coating method, and a liquid crystal display element having excellent display characteristics and reliability.

At present, as a liquid crystal display element, a liquid crystal alignment film containing polyamic acid, polyimide or the like is formed on the surface of a substrate provided with a transparent conductive film such as ITO (indium oxide-tin oxide) And a nematic liquid crystal layer having positive dielectric anisotropy is formed in the gap to form a cell having a sandwich structure so that the long axis of the liquid crystal molecules is continuously twisted by 90 DEG from one substrate toward the other substrate , TN type liquid crystal display devices having so-called TN (Twisted Nematic) type liquid crystal cells are known. Further, STN (Super Twisted Nematic) type liquid crystal display devices having higher contrast and less time dependency than TN type liquid crystal display devices have been developed. This STN type liquid crystal display device uses a liquid crystal in which a chiral agent as an optically active substance is blended with a nematic liquid crystal and a birefringence effect caused by a state in which the long axis of the liquid crystal molecule is continuously twisted over 180 degrees between the substrates .

Recently, a transverse electric field type liquid crystal display device has been proposed in which liquid crystal molecules are controlled by arranging two electrodes for driving a liquid crystal in a comb shape on one substrate to generate an electric field parallel to the substrate surface. This device is generally referred to as an infra-red switching type (IPS type) and is known to have a wide viewing angle. Particularly when the IPS type device is used in combination with the optical compensation film, the viewing angle characteristic can be further improved, and a wide viewing angle comparable to that of a cathode ray tube without gradation reversal or color tone change can be obtained.

In addition to these, a vertical alignment type liquid crystal display device called a MVA (Multi-Domain Vertical Alignment) method or a PVA (Patterned Vertical Alignment) method in which liquid crystal molecules having negative dielectric anisotropy are oriented perpendicular to a substrate has been proposed Japanese Patent Application Laid-Open No. 11-258605 and "Liquid Crystal", Vol. 3 (No. 2), p117 (1999)). These vertical alignment type liquid crystal display devices are excellent in terms of manufacturing process, such as excellent viewing angle, contrast and the like, and no rubbing treatment is required in forming a liquid crystal alignment film.

However, recently, the spread of liquid crystal televisions is progressing, and a large-scale line called the "seventh generation " In addition, the construction of the "Eighth Generation" line, which is larger, is also planned. Advantages of enlarging the size of a substrate using a large-size line include that a plurality of panels can be obtained from a single substrate, so that the process time can be shortened and the cost can be reduced, and the size of the liquid crystal display device itself can be coped with . On the other hand, a disadvantage of the enlargement of the substrate is that it becomes difficult to ensure uniformity of printing of the liquid crystal aligning agent over a large area. Particularly, when a liquid crystal alignment film over a large area is formed by an offset printing machine widely used in the past, defects in electrical characteristics of the liquid crystal alignment film due to printing failure of the liquid crystal alignment agent may occur .

In order to solve the above problem, studies have been made using an ink jet coating method for forming a liquid crystal alignment film. An advantage of the ink-jet coating method is that since the liquid crystal aligning agent used in printing is substantially equal to the liquid amount actually applied, the use amount of the liquid crystal aligning agent can be reduced and no replacement or cleaning is required because no printing plate is used And the like, which can reduce the time, labor, and cost required for maintenance, etc., and have flexibility to cope with various panel sizes.

In order to produce a liquid crystal display element with a high yield on a large substrate manufactured by a large-scale line, a liquid crystal aligning agent having more excellent printability than ever in the inkjet coating method is required. In addition, recent demands for improvement in display quality have become more severe. In particular, a liquid crystal alignment film having a liquid crystal alignment property and an electric characteristic at or above the current level is required.

The present invention has been made based on the above-described circumstances, and its object is to provide an inkjet printing method which is excellent in printing property particularly in an inkjet coating method and can improve the yield of a product in a manufacturing process by a large- A liquid crystal aligning agent which provides a liquid crystal alignment film excellent in various performances, and a liquid crystal display element which exhibits high quality display characteristics and is excellent in reliability.

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

According to the present invention, the above objects and advantages of the present invention are achieved by a

A liquid crystal aligning agent containing at least one polymer selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride and a diamine compound and a polyimide obtained by dehydration ring closure thereof,

Solvent

(A) a first solvent comprising a compound represented by the following formula (I)

(B) a group consisting of N-methyl-2-pyrrolidone,? -Butyrolactone, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylformamide and N, N- A second solvent comprising at least one selected from the group consisting of:

(C) a third solvent comprising at least one member selected from the group consisting of butyl cellosolve, diacetone alcohol, propylene carbonate, diethylene glycol diethyl ether and ethyl-3-ethoxypropionate

And a liquid crystal aligning agent.

(In the formula (I), each R is independently an alkyl group having 3 to 10 carbon atoms)

The above objects and advantages of the present invention can be achieved by providing

And a liquid crystal alignment film obtained from the liquid crystal aligning agent.

The liquid crystal aligning agent of the present invention can improve the yield of the product in a manufacturing process by a large-scale line, especially because it has excellent applicability when it is used in an inkjet coating method. Further, the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention is excellent in various performances such as liquid crystal aligning ability, electrical characteristics and the like, and is particularly preferable for application to vertically aligned liquid crystal display devices.

The liquid crystal display element of the present invention having the liquid crystal alignment film is preferably used as a display device of various devices such as a desk calculator, a wrist watch, a desk clock, a mobile phone, a coefficient display board, a word processor, a personal computer, Can be used.

Hereinafter, the present invention will be described in detail.

The liquid crystal aligning agent of the present invention contains at least one polymer selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride and a diamine compound and a polyimide obtained by dehydration cyclization thereof, and a solvent.

[Tetracarboxylic acid dianhydride]

Examples of the tetracarboxylic acid dianhydride used for synthesizing the polyamic acid or polyimide contained in the liquid crystal aligning agent of the present invention include, for example,

(Wherein R ¹ is each independently a hydrogen atom, a chlorine atom or an alkyl group having 1 to 6 carbon atoms)

, A compound represented by the following formula (2)

(Wherein R ² is each independently an alkyl group having 1 to 6 carbon atoms and n is an integer of 0 to 4)

, Butane tetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 3,3 ', 4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,2,4-tricarboxycyclopentylacetic dianhydride, bicyclo [2.2. 1] heptane-2,3,5,6-tetracarboxylic dianhydride, 3,5,6-tricarboxy norbornane-2-acetic acid dianhydride, tetracyclo [4.4.0.1 ^{2,5 . 10} ] dodecane-3,4,8,9-tetracarboxylic acid dianhydride, 2,3,4,5-tetrahydrofuran tetracarboxylic acid dianhydride, 5- (2,5-dioxotetrahydrofuran ) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid dianhydride, bicyclo [2.2.2] -oct-4-ene-2,3,5,6-tetracarboxylic acid dianhydride , Bicyclo [2.2.2] -octo-7-ene-2,3,5,6-tetracarboxylic dianhydride, the following structural formulas (II-1) and (II-2)

(Wherein R ³ and R ⁵ are each a divalent organic group having an aromatic ring, R ⁴ and R ⁶ are each a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and a plurality of R ⁴ and R ⁶ present are the same Or may be different)

Aliphatic or alicyclic tetracarboxylic acid dianhydride such as a compound represented by each of the following formulas:

Pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylsulfonetetracarboxylic acid dianhydride, 1,4,5 , 8-naphthalene tetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3 ', 4,4'-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3', 4,4'-tetraphenylsilane tetracarboxylic dianhydride, 1,2,3,4-furan tetracarboxyl Acid dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfide dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4 , 4'-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ', 4,4'-perfluoroisopropylidene diphthalic acid dianhydride, 3,3' '-Biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, ethylene glycol-bis (anhydrotrimellitic acid Propane glycol-bis (anhydrotrimellitate), 1,4-butanediol-bis (anhydrotrimellitate), 1,6-hexanediol-bis (anhydrotrimellitate) Bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate), the following chemical formulas (3) to (6)

And aromatic tetracarboxylic acid dianhydride such as a compound represented by each of the following formulas.

Specific examples of the compound represented by the formula (1) include 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,2-dimethyl-1,2,3,4-cyclo Butane tetracarboxylic acid dianhydride, 1,2-diethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracar 1,3-diethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3-dichloro-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3- Water, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, etc. Among them, 1,2,3,4-cyclobutanetetracarboxylic acid Dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,2-diethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride , 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride or 1,3-diethyl-1,2,3,4-cyclobutanetetracar Bicylic acid dianhydride is preferred.

Specific examples of the compound represented by the formula (2) include 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo-3-furanyl) -Naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-methyl-5- (tetrahydro- 3-dione, 1,3,3a, 4,5,9b-hexahydro-5-ethyl-5 (tetrahydro-2, Furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-methyl-5 ( 1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7,7-dihydro- -Ethyl 5- (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 [ (Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [l, 2-c] -furan-1,3-dione, 1, , 3,3a, 4,5,9b-hexahydro-5,8-dimethyl-5 (tetrahydro-2, Dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione.

These tetracarboxylic acid dianhydrides may be used singly or in combination of two or more.

Among them, the compound represented by the formula (1), the compound represented by the formula (2), pyromellitic dianhydride, 1,2,4-tricarboxycyclopentyl acetic acid dianhydride, 2,3,5-tri At least one selected from the group consisting of carboxycyclopentyl acetic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride and 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride ( (Hereinafter also referred to as "specific tetracarboxylic dianhydride") is preferably used as the tetracarboxylic acid dianhydride.

When the polymer contained in the liquid crystal aligning agent of the present invention is a polyamic acid, the tetracarboxylic acid dianhydride used for synthesizing the polyamic acid is preferably at least 10 mol% based on the total amount of the tetracarboxylic acid dianhydride , More preferably 20 mol% or more, and still more preferably 40 mol% or more. In this case, as the tetracarboxylic acid dianhydride other than the specific tetracarboxylic dianhydride, it is preferable to use an alicyclic tetracarboxylic dianhydride.

On the other hand, when the polymer contained in the liquid crystal aligning agent of the present invention is polyimide, the tetracarboxylic acid dianhydride used for synthesizing the polyimide is preferably a tetracarboxylic dianhydride of 50 Mol% or more, more preferably 70 mol% or more, further preferably 80 mol% or more. In this case, as the tetracarboxylic acid dianhydride other than the specific tetracarboxylic dianhydride, it is preferable to use an alicyclic tetracarboxylic dianhydride.

[Diamine compound]

Examples of the diamine compound used for synthesizing the polyamic acid or polyimide contained in the liquid crystal aligning agent of the present invention include compounds represented by the following formulas (III-1) and (III-2)

(Wherein X ¹ independently represents a single bond, -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH-, -S-, a methylene group, an alkyl of 2 to 6 R ⁷ is a monovalent organic group having an alkyl group of 10 to 20 carbon atoms, an alicyclic group having an alicyclic skeleton of 4 to 40 carbon atoms, or a monovalent organic group having a fluorine atom of 6 to 20 carbon atoms, and R ⁸ is a carbon number A divalent organic group having 4 to 40 alicyclic skeletons)

, And other diamine compounds.

Examples of the alkyl group having 10 to 20 carbon atoms represented by R ⁷ in the above formula (III-1) include n-decyl, n-dodecyl, n-pentadecyl, An octadecyl group, and an n-eicosyl group. Examples of the alicyclic skeleton included in the monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms include alicyclic skeletons derived from cycloalkanes such as cyclobutane, cyclopentane, cyclohexane, and cyclodecane; Bridged alicyclic skeletons such as norbornene and adamantane; Steroid skeleton, and the like.

Here, the steroid skeleton refers to a skeleton in which one or two or more carbon-carbon bonds in the structure including the cyclopentano-perhydrophenanthrene nucleus are double-bonded. The monovalent organic group having a steroid skeleton of R ⁷ preferably has 17 to 40 carbon atoms, more preferably 17 to 29 carbon atoms. Specific examples of R ⁷ having such a steroid skeleton include, for example, a cholestan-3-yl group, a cholesta-5-en-3-yl group, a cholesta- Di-3-yl group and the like.

The monovalent organic group having an alicyclic skeleton of R ⁷ may have a part or all of its hydrogen atoms substituted with a halogen atom, preferably a fluorine atom. Examples of the monovalent organic group having 6 to 20 carbon atoms and having a fluorine atom include straight chain alkyl groups having 6 to 20 carbon atoms such as n-hexyl group, n-octyl group and n-decyl group; An alicyclic hydrocarbon group having 6 to 20 carbon atoms such as a cyclohexyl group and a cyclooctyl group; And aromatic hydrocarbon groups having 6 to 20 carbon atoms, such as a phenyl group and a biphenyl group, in which some or all of the hydrogen atoms are substituted with a fluorine atom or a fluoroalkyl group (provided that the number of carbon atoms of R ⁷ is Lt; RTI ID = 0.0 > fluoroalkyl < / RTI >

X ¹ in the above formula (III-1) is preferably -O-, -CO-, -COO- or -OCO-.

Specific examples of the diamine compound represented by the above formula (III-1) include dodecaneoxy-2,4-diaminobenzene, pentadecaneoxy-2,4-diaminobenzene, hexadecanoxy- , 4-diaminobenzene, octadecanoxy-2,4-diaminobenzene, the following formulas (7) to (22)

, And the like.

Examples of the alicyclic skeleton included in the divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms and represented by R ⁸ in the above formula (III-2) include cyclobutane, cyclopentane, cyclohexane, cyclodecane An alicyclic skeleton derived from a cycloalkane such as a cycloalkane; Bridged alicyclic skeletons such as norbornene and adamantane; Steroid skeleton, and the like.

Wherein the steroid skeleton is the same as the steroid skeleton in R ⁷ above. The divalent organic group having a steroid skeleton of R ⁸ preferably has 17 to 40 carbon atoms, more preferably 17 to 29 carbon atoms. Specific examples of R ⁸ having a steroid skeleton include, for example, a cholestane-3,3-diyl group, a cholestan-3,6-diyl group, a cholesta- Ene-3,6-diyl group, cholesta-5,24-diene-3,6-diyl group, and the like.

The divalent organic group having an alicyclic skeleton of R ⁸ may have a part or all of its hydrogen atoms substituted with a halogen atom, preferably a fluorine atom.

Specific examples of the diamine compound represented by the above formula (III-2) include, for example, the following formulas (23) to (27)

, And the like.

Examples of the other diamine compounds include p-phenylenediamine, 2-methyl-1,4-phenylenediamine, 2-ethyl-1,4-phenylenediamine, 2,5- - phenylenediamine, 2,5-diethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, m- Diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, 2,2'-dimethyl-4,4 Diaminobiphenyl, 2,2'-di (trifluoromethyl) -4,4'-diaminobiphenyl, 2,2'-diethyl-4,4'-diaminobiphenyl, 3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-di (trifluoromethyl) -4,4'-diaminobiphenyl, -Diaminobiphenyl, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 2,2'-dimethyl-4,4'- (4'-aminophenyl) -1,3,3-trimethylindane, 3-amino-1- , 4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2-bis [4- (Aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2- Bis (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, 2,7-diaminofluorene, 9,9 Bis (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'- diaminobiphenyl, 1,4,4 '- (m-phenylene isopropylidene) bisaniline, 2,2'-bis [4- (4-amino Bis (trifluoromethyl) biphenyl, 4,4'-bis [4 (4-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4'-diamino- -Amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl, and 4- (4-n-heptylcyclohexyl) phenoxy-2,4-diaminobenzene;

Aliphatic diamines such as 1,3-bis (aminomethyl) benzene, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine and nonamethylenediamine;

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, 2-aminopyridine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine, and the like, Diamines having a nitrogen atom;

(28) to (30): < EMI ID =

(Wherein each R ⁹ is independently a hydrocarbon group of 1 to 12 carbon atoms, p is independently an integer of 1 to 3, q is an integer of 1 to 20, y is an integer of 2 to 12, z Is an integer of 1 to 5)

, And the like.

Examples of other diamine compounds include p-phenylenediamine, 2-methyl-1,4-phenylenediamine, 2-ethyl-1,4-phenylenediamine, 2,5- , 2,5-diethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 4,4'-diaminodiphenylmethane, 2,2 ' -Dimethyl-4,4'-diaminobiphenyl, 2,2'-di (trifluoromethyl) -4,4'-diaminobiphenyl, 2,2'-diethyl- Diminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-diethyl-4,4'-diaminobiphenyl, 3,3'-di (trifluoromethyl ) -4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 2,2-bis (4-aminophenyl) Bis (4-aminophenyl) hexafluoropropane, 2,6-diaminopyridine or 3,4-diaminopyridine are preferable.

These diamine compounds may be used alone or in combination of two or more.

When the liquid crystal aligning agent of the present invention is used as a vertically aligned liquid crystal aligning agent, the diamine compound used for synthesizing the polyamic acid or polyimide contained in the liquid crystal aligning agent is preferably a diamine represented by the above formula (III-1) And a diamine compound represented by the above formula (III-2). In this case, the amount of the diamine compound represented by the formula (III-1) or (III-2) in the total amount of the diamine compound is preferably 7 mol% or more, and more preferably 10 mol% or more.

[Synthesis of polyamic acid]

The polyamic acid which may be contained in the liquid crystal aligning agent of the present invention can be obtained by reacting the tetracarboxylic dianhydride and the diamine compound as described above.

The ratio of the tetracarboxylic dianhydride and the diamine to be 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 from 0.2 to 2.0 equivalents based on 1 equivalent of the amino group of the diamine, Is 0.8 to 1.2 equivalents. The synthesis reaction of the polyamic acid is preferably carried out in an organic solvent, preferably at a temperature of -20 DEG C to 150 DEG C, more preferably 0 DEG C to 100 DEG C, preferably 0.5 to 24 hours, It is done for 10 hours.

The organic solvent usable herein is not particularly limited as long as it can dissolve the polyamic acid to be synthesized, and examples thereof include 1-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, Amide, dimethyl sulfoxide,? -Butyrolactone, tetramethyl urea, and hexamethylphosphotriamide; phenol-based solvents such as m-cresol, xylenol, phenol, halogenated phenol and the like. The amount (?) Of the organic solvent is preferably such that the total amount (?) Of the tetracarboxylic dianhydride and the diamine compound is 0.1 to 30% by weight based on the total amount (? +?) Of the reaction solution.

The organic solvent may be used by replacing a part of the organic solvent by alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbon or the like which is a poor solvent of polyamic acid within a range in which the produced polyamic acid is not precipitated.

Specific examples of such a poor solvent include alcohols such as methanol, ethanol, isopropanol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol, propylene glycol, But are not limited to, 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-diethyl ether, diethylene glycol, Dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, di Diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene and the like.

When a part of the organic solvent is replaced with a poor solvent, the amount of the poor solvent to be used is preferably 50% by weight or less based on the total amount of the organic solvent.

As described above, a reaction solution obtained by dissolving polyamic acid is obtained. The polyamic acid solution may be directly supplied to the dehydration ring-closing reaction of the subsequent process, or may be provided to the dehydration ring-closing reaction after the polyamic acid contained in the reaction solution is isolated, or after the isolated polyamic acid is purified, May be provided to the reaction. The isolation of polyamic acid can be carried out by pouring the polyamic acid 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 polyamic acid solution under reduced pressure with an evaporator. The polyamic acid can also be purified by once or several times the method of dissolving the polyamic acid thus obtained in an organic solvent and then precipitating with a poor solvent or by distillation under reduced pressure with an evaporator.

[Synthesis of polyimide]

The polyimide which can contain the liquid crystal aligning agent of the present invention can be synthesized by dehydrating and ring closure of the polyamic acid. The polyimide used in the present invention may be a complete imide precursor in which all of the amic acid structure of the polyamic acid is imidized or a partial imide precursor in which only a part of the amic acid structure is imidized and the amic acid structure and the imide structure coexist It may be a cargo. When the polymer contained in the liquid crystal aligning agent of the present invention is polyimide, its imidization ratio is preferably 40% or more. Herein, the term "imidization rate" refers to a value indicating the ratio of the number of imide structures occupying the amic acid structure and the total number of imide structures in the polymer as a percentage. Imidization ratio is sufficiently dried polyimide a suitable deuterated solvent such as deuterated dimethyl sulfoxide was dissolved in the seed, in the ¹ H-NMR was measured at room temperature as a reference tetramethylsilane material, to obtain by the formula (1) .

Wherein A1 is a peak area (about 10 ppm) derived from the proton of the NH group, A2 is a peak area (7 to 8 ppm) derived from the proton of the aromatic ring, and? The ratio of the number of proton in the aromatic ring to one proton in the group)

The dehydration ring closure of polyamic acid can be carried out by a method of (1) heating polyamic acid, or (2) dissolving polyamic acid in an organic solvent, adding a dehydrating agent and dehydrating ring-closing catalyst to the solution, .

The reaction temperature in the method of heating the polyamic acid of (1) is preferably 50 to 200 ° C, more preferably 60 to 170 ° C. If the reaction temperature is less than 50 캜, the dehydration ring-closure reaction does not proceed sufficiently, and if the reaction temperature exceeds 200 캜, the molecular weight of the obtained polyimide may be lowered. The reaction time is preferably 0.5 to 72 hours, more preferably 1 to 10 hours.

On the other hand, as the dehydrating agent in the method of adding the dehydrating agent and the dehydrating ring-closing catalyst to the solution of the polyamic acid of the above (2), for example, an acid anhydride such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride can be used. The amount of the dehydrating agent to be used is preferably 0.01 to 20 mol based on 1 mol of the amic acid structure of the polyamic acid, though it depends on the desired imidization rate. As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, collidine, lutidine and triethylamine can be used. However, it is not limited to this. 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 used. The imidization rate can be increased as the amount of the dehydrating agent and the dehydrating ring closure agent used increases. Examples of the organic solvent used in the dehydration ring-closing reaction include those used for the synthesis of polyamic acid, and the same organic solvents as those exemplified. 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 12 hours, more preferably 1 to 6 hours.

The imidized polymer obtained by the above method (1) may be directly supplied to the preparation of a liquid crystal aligning agent, or may be provided for the production of a liquid crystal aligning agent after the obtained imidized polymer is purified. On the other hand, in the above method (2), a reaction solution containing an imidized polymer is obtained. This reaction solution may be directly supplied to the preparation of a liquid crystal aligning agent or may be provided to the preparation of a liquid crystal aligning agent after removing the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution. Alternatively, after the imidized polymer is isolated, May be provided for production, or may be provided for 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 carried out by carrying out the same operations as those described above as a method for isolation and purification of polyamic acid.

[Polymer of terminal modified type]

The polyamic acid or polyimide used in the present invention may be a terminal modified type having a controlled molecular weight. By using a polymer of a terminal modification type, the effect of the present invention is not impaired and the coating properties and the like of the liquid crystal aligning agent can be further improved.

Such a terminal modified polymer can be synthesized by adding an appropriate molecular weight regulator such as anhydride monoacid, monoamine compound, or monoisocyanate compound to the reaction system in the synthesis of the polyamic acid. Examples of the acid anhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride, n-hexadecylsuccinic anhydride and the like . 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.

The polyamic acid or imidized polymer obtained as described above preferably has a solution viscosity of 20 to 800 mPa · s and a solution viscosity of 30 to 500 mPa · s desirable.

The solution viscosity (mPa 占 퐏) of the polymer is preferably 10% by weight of a polymer solution prepared by using a good solvent for the polymer (e.g.,? -Butyrolactone, N-methyl- Is a value measured at 25 DEG C using an E-type rotational viscometer.

[Optional additives]

The liquid crystal aligning agent of the present invention contains at least one polymer selected from the group consisting of the above-mentioned polyamic acid and polyimide and a solvent described later as an essential component. In addition, An epoxy compound or a functional silane compound may be contained as an additive. These can be added for the purpose of further improving the adhesion of the formed liquid crystal alignment film to the substrate surface.

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 N, N ', N'-tetraglycidyl-p-phenylenediamine, N, N, N', N'- tetraglycidyl- N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N, N'N'N'N'N'-diaminodiphenyl ether, N, N, N ', N'-tetraglycidyl-2,2'-dimethyl- Tetraglycidyl-1, 2-diaminocyclohexane, N, N, N ', N'-tetramethylcyclohexane, N, Aminocyclohexyl) methane, bis (N, N-diglycidyl-2-methyl-4-aminocyclohexyl) Methylene-4-aminocyclohexyl) methane, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1,4 Bis (N, N-diglycidylaminomethyl) benzene, 1,4-bis (N, N-diglycidylaminomethyl) cyclohexane, (N, N-diglycidylaminomethyl) benzene, 1,3,5-tris (N, N-diglycidylaminomethyl) cyclohexane, 1,3,5- (31) to (35)

, And the like. The mixing ratio of these epoxy compounds is preferably 40 parts by weight or less, more preferably 40 parts by weight or less, based on 100 parts by weight of the total amount of the polymers (the total amount of the polyamic acid and the imidized polymer thereof 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- ( Aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3- Ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-tri Methoxysilylpropyl triethylenetriamine, 10-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, Aminopropyltriethoxysilane, 3- (N-allyl-N-glycidyl) aminopropyltrimethoxysilane, 3- (N, N-diglycidyl) amino Propyl trimethoxysilane and the like.

The blending ratio of these functional silane compounds is preferably 2 parts by weight or less, more preferably 0.2 to 1 part by weight based on 100 parts by weight of the total amount of the polymer.

[Liquid crystal aligning agent]

The liquid crystal aligning agent of the present invention comprises at least one polymer selected from the group consisting of the above-mentioned polyamic acid and polyimide and optionally added optional components dissolved in a solvent.

The solvent used in the liquid crystal aligning agent of the present invention is

(A) a first solvent comprising a compound represented by the above formula (I)

(B) a group consisting of N-methyl-2-pyrrolidone,? -Butyrolactone, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylformamide and N, N- A second solvent comprising at least one selected from the group consisting of:

(C) a third solvent comprising at least one member selected from the group consisting of butyl cellosolve, diacetone alcohol, propylene carbonate, diethylene glycol diethyl ether and ethyl-3-ethoxypropionate

.

The compound represented by the formula (I) preferably has a boiling point of 140 to 200 ° C and a surface tension of 18 to 27 mN / m. From the viewpoint of setting the boiling point and the surface tension of the compound represented by the formula (I) within the above range, R in the formula (I) is preferably an alkyl group having 4 to 8 carbon atoms, more preferably 4 to 6 carbon atoms Alkyl group, and specific examples thereof include an amyl group and an isopentyl group.

Specific examples of the compound represented by the above formula (I) include, for example, diamyl ether and diisopentyl ether, and it is preferable to use at least one selected from these.

In the liquid crystal aligning agent of the present invention, the ratio of the first solvent (A) to the total of the first solvent (A), the second solvent (B) and the third solvent (C) is preferably from 0.5 to 20% , And more preferably 1 to 10 wt%. The ratio of the second solvent (B) to the total amount of the first solvent (A), (B) the second solvent and (C) the third solvent is preferably 10 to 94.5% by weight, more preferably 30 to 89% More preferable. The ratio of the (C) third solvent to the sum of (A) the first solvent, (B) the second solvent and (C) the third solvent is preferably 5 to 70% by weight, more preferably 10 to 60% More preferable.

In the liquid crystal aligning agent of the present invention, when the first solvent (B), the second solvent (B) and the third solvent (C) are contained preferably in the above-mentioned ratio, the desired effect of the present invention, And excellent coating properties can be preferably realized in the coating method. Particularly when (A) the compound represented by the formula (I) in which the boiling point and the surface tension are in the above ranges is used as the first solvent, (A) even when the content ratio of the first solvent is relatively small, Can be expressed to the maximum extent.

(A) the first solvent, (B) the second solvent and (C) the third solvent may be used as the solvent. C) Other solvents may be used together with the third solvent. Examples of the other solvent that can be used here include γ-butyrolactam, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, methyl methoxy propionate, ethylene Ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol monomethyl ether, Diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, and the like.

The solvent composition in the liquid crystal aligning agent of the present invention is such that the polymer and optional additives are not precipitated in the liquid crystal aligning agent and the surface tension of the liquid crystal aligning agent is in the range of 20 to 40 mN / m. From this point of view, the ratio of the total amount of (A) the first solvent, (B) the second solvent and (C) the third solvent in the liquid crystal aligning agent of the present invention to the total amount of the solvent is preferably 30% More preferably 50% by weight or more, and further preferably 70% by weight 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 in the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is selected in consideration of viscosity, volatility, etc., To 10% by weight. That is, when the solid concentration of the liquid crystal aligning agent is less than 1% by weight, the film thickness of the above-mentioned coating film becomes too small, and a good liquid crystal alignment film is formed On the other hand, when the concentration of the solid content exceeds 10% by weight, the film thickness of the coating film becomes excessively large and a good liquid crystal alignment film can not be obtained, and the viscosity of the liquid crystal aligning agent is increased, . Particularly preferable range of the solid concentration is 2 to 8% by weight, and it is particularly preferable that the solution viscosity of the liquid crystal aligning agent is in the range of 3 to 15 mPa · s.

The temperature in the production of the liquid crystal aligning agent of the present invention is preferably from 0 캜 to 60 캜, more preferably from 20 캜 to 40 캜.

[Method of producing liquid crystal display element]

The liquid crystal display element of the present invention comprises the liquid crystal alignment layer formed from 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 method.

(1) First, the liquid crystal alignment film of the present invention is applied on a pair of substrates, and the solvent is removed to form a coating film. When a display mode of a liquid crystal display element to be manufactured is a vertical electric field system such as TN type, STN type or VA type, two substrates provided with a transparent conductive film patterned on one side are used as a pair of substrates. On the other hand, when the display mode of the liquid crystal display element to be manufactured is a transverse electric field system, a substrate provided with a transparent conductive film having a comb-shaped pattern and a substrate having no transparent conductive film are used as a pair of substrates.

In any of the above cases, the liquid crystal aligning agent is applied on the substrate (on the side having the transparent conductive film on the substrate when the substrate has the transparent conductive film). Examples of the substrate include glass such as float glass and soda glass; A transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, and poly (alicyclic olefin) can be used. Examples of the transparent conductive film provided on one surface of the substrate include a NESA film (registered in the US PPG company) and indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) containing tin oxide (SnO ₂ ) An ITO film or the like can be used. In order to obtain these patterned transparent conductive films, a method of forming a pattern by a photo-etching method after forming a transparent conductive film without a pattern, a method of forming a patterned transparent conductive film by using a mask having a desired pattern in forming a transparent conductive film, A method of directly forming a transparent conductive film, or the like can be adopted.

The application of the liquid crystal aligning agent onto the substrate can be performed by a suitable application method such as a roll coater method, a spinner method, a printing method, or an inkjet method. The liquid crystal aligning agent of the present invention has an advantage of being able to exert particularly good applicability (printability) when the ink jet printing method is employed as a coating method.

A functional silane compound, a functional titanium compound and the like may be previously applied to the surface to be coated of the substrate in order to improve the adhesiveness between the substrate surface and the transparent conductive film and the coating film during application of the liquid crystal aligning agent.

Pre-heating (pre-baking) is preferably performed for the purpose of preventing the liquid from flowing out of the applied alignment agent after application. The prebaking temperature is preferably 30 to 200 占 폚, more preferably 40 to 150 占 폚, particularly preferably 40 to 100 占 폚. The prebaking time is preferably 10 seconds to 20 minutes, more preferably 10 seconds to 10 minutes. Thereafter, a baking (post-baking) step is performed for the purpose of completely removing the solvent or the like. This post-baking is intended to completely remove the solvent from the coating film. When the polymer contained in the liquid crystal aligning agent of the present invention is a polymer having an amic acid structure, To further promote the dehydration ring closure of the amic acid structure of the polymer to further enhance the imidization rate of the coating film. The post-baking temperature is preferably 80 to 300 占 폚, more preferably 120 to 250 占 폚. The post baking time is preferably 5 to 60 minutes, more preferably 5 to 30 minutes.

In this manner, a coating film that becomes a liquid crystal alignment film can be formed. 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.

In the case where the liquid crystal display element to which the liquid crystal aligning agent of the present invention is applied is a VA type liquid crystal display element, for example, after a projected dried body described in Japanese Patent Application Laid-Open No. 2002-327058 is formed on a substrate, It is also possible to improve the viewing angle characteristics by applying an alignment agent.

(2) When the display mode of the liquid crystal display element to be produced is of the VA type, the coating film formed as described above can be used as the liquid crystal alignment film as it is, but rubbing treatment described later can also be performed if necessary. On the other hand, rubbing treatment is performed on the coated film surface formed when the display mode of the liquid crystal display element to be manufactured is the vertical electric field system other than the VA type or when the transverse electric field system is used.

The rubbing treatment can be carried out by a method of rubbing the fabric in a certain direction with a roll formed of fibers such as nylon, rayon or cotton, for example. Accordingly, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film. Further, with respect to the coated film after the rubbing treatment, ultraviolet rays are irradiated to a part of the liquid crystal alignment film as shown in, for example, Japanese Patent Application Laid-Open Nos. 6-222366 and 6-281937, A process of changing the pretilt angle of a part of the alignment film or a process of forming a resist film on a part of the surface of the liquid crystal alignment film as shown in Japanese Patent Application Laid-open No. 5-107544, It is possible to improve the clock characteristic of the obtained liquid crystal display element by performing a treatment for removing the resist film after the treatment and making the liquid crystal alignment film have different liquid crystal aligning ability for each region.

(3) A liquid crystal cell is prepared by preparing two substrates on which a liquid crystal alignment film is formed as described above, and arranging the liquid crystal between two substrates arranged opposite to each other. Here, when the coating film is subjected to the rubbing treatment, the two substrates are opposed to each other such that the rubbing directions of the respective coating films are made to have a predetermined angle, for example, orthogonal or inversely.

In order to produce a liquid crystal cell, for example, the following two methods can be used.

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

The second method is a so-called ODF (One Drop Fill) method. For example, an ultraviolet-light curable sealing material is applied to a predetermined place on one of the two substrates on which the liquid crystal alignment film is formed and the liquid crystal is further dropped on the liquid crystal alignment film surface, And subsequently, the entire surface of the substrate is irradiated with ultraviolet light to cure the sealing agent, whereby the liquid crystal cell can be manufactured.

Regarding the liquid crystal cell manufactured as described above, the liquid crystal used in the above-mentioned method is further heated to a temperature at which the liquid crystal used has an isotropic phase, and then slowly cooled to room temperature to remove the flow orientation at the time of liquid crystal injection desirable.

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

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

As the liquid crystal, for example, a nematic liquid crystal, a smectic liquid crystal and the like can be used, and among them, a nematic liquid crystal is preferable. In the VA type liquid crystal cell, a nematic liquid crystal having a negative dielectric anisotropy is preferable, and examples thereof include a dicyanobenzene liquid crystal, a pyridazine liquid crystal, a Schiffbaic acid liquid crystal, an agar liquid crystal, a biphenyl liquid crystal, Hexane-based liquid crystal or the like is used. In the case of a TN type liquid crystal cell or an STN type liquid crystal cell, a nematic liquid crystal having a positive dielectric anisotropy is preferable. For example, biphenyl type liquid crystal, phenyl cyclohexane type liquid crystal, ester type liquid crystal, terphenyl type liquid crystal, A cyclohexane-based liquid crystal, a pyrimidine-based liquid crystal, a dioxane-based liquid crystal, a bicyclooctane-based liquid crystal, a quartz-based liquid crystal, or the like. Examples of the liquid crystal include cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonanoate, and cholesteryl carbonate; A chiral agent sold under the trade names C-15 and CB-15 (manufactured by Merck Ltd.); p-disiloxybenzylidene-p-amino-2-methylbutyl cinnamate, and the like can be further added and used.

As the polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing plate in which a polarizing film called "H film " in which iodine is absorbed while stretching polyvinyl alcohol in a stretched orientation is sandwiched by a cellulose acetate protective film, or a polarizing plate including the H film itself have.

<Examples>

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

&Lt; Synthesis Example 1 &

10 mmol of the compound represented by the above formula (11), 70 mmol of p-phenylenediamine and 20 mmol of 4,4'-diaminodiphenylmethane as a diamine compound in N-methyl-2-pyrrolidone, 100 mmol of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as an acid dianhydride was added in this order to obtain a solution in which the total amount of the tetracarboxylic acid dianhydride and the diamine compound was 20% by weight based on the total amount of the solution , And the reaction was carried out at 60 DEG C for 4 hours to obtain a solution containing polyamic acid.

To the solution containing the polyamic acid, pyridine and acetic anhydride in an amount of two times that of the total amount (theoretical value) of the amic acid structure contained in the polyamic acid were added, and the mixture was heated to 110 DEG C and dehydration ring- Respectively.

The resulting solution was poured into a large excess of diethyl ether to obtain a precipitate, which was recovered and dried under reduced pressure to obtain a polyimide (PI-1) having an imidization rate of 78%.

&Lt; Synthesis Example 2 &

110 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride and 38 g (0.35 mol) of p-phenylenediamine as diamine, 4,4'-diaminodiphenyl 20 g (0.1 mol) of methane and 26 g (0.05 mol) of 3- (3,5-diaminobenzoyloxy) cholestane were dissolved in 800 g of N-methyl-2-pyrrolidone, To obtain a solution containing polyamic acid. The solution viscosity of the obtained polyamic acid solution was measured as a solution having a polyamic acid concentration of 10% by weight by adding a small amount of N-methyl-2-pyrrolidone and measuring 60 mPa · s.

Then, 1,800 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, and 80 g of pyridine and 100 g of acetic anhydride were added and the dehydration ring-closure reaction was carried out 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 reaction were removed from the system by this solvent substitution operation, the same applies hereinafter) Approximately 1,100 g of a solution containing 15% by weight of 80% imidation polymer (PI-2) was obtained. A small amount of this imidized polymer solution was collected, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight by adding? -Butyrolactone was 87 mPa 占 퐏.

&Lt; Synthesis Example 3 &

110 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride and 43 g (0.40 mol) of p-phenylenediamine as diamine and 3- (3,5-diamino Benzoyloxy) cholestane (52 g, 0.10 mole) was dissolved in 830 g of N-methyl-2-pyrrolidone and reacted at 60 DEG C for 6 hours to obtain a solution containing the polyamic acid. A small amount of the obtained polyamic acid solution was fractionated and the solution viscosity was measured as a solution having a polyamic acid concentration of 10% by weight by adding N-methyl-2-pyrrolidone to a viscosity of 60 mPa · s.

Next, 1,900 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, and 40 g of pyridine and 51 g of acetic anhydride were added, followed by dehydration ring closure reaction at 110 ° C for 4 hours. After the dehydration ring closure reaction, about 1,200 g of a solution containing 15% by weight of an imidation polymer (PI-3) having an imidization rate of about 50% was obtained by replacing the solvent in the system with fresh N-methyl- . A small amount of this imidized polymer solution was collected, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight by adding N-methyl-2-pyrrolidone was 47 mPa · s.

&Lt; Synthesis Example 4 &

110 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride and 49 g (0.45 mol) of p-phenylenediamine as diamine and 3- (3,5-diamino Benzoyloxy) cholestane (26 g, 0.05 mol) was dissolved in 750 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 the solution viscosity was measured as a solution having a polyamic acid concentration of 10% by weight by adding N-methyl-2-pyrrolidone was 58 mPa · s.

Then, 1,800 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, and 40 g of pyridine and 51 g of acetic anhydride were added, followed by dehydration ring closure reaction at 110 ° C for 4 hours. After the dehydration ring closure reaction, about 1,100 g of a solution containing 15% by weight of an imidation polymer (PI-4) having an imidization rate of about 50% was obtained by replacing the solvent in the system with fresh N-methyl-2-pyrrolidone . A small amount of this imidized polymer solution was collected, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight by adding N-methyl-2-pyrrolidone was 85 mPa · s.

&Lt; Example 1 >

The polyimide (PI-1) obtained in Synthesis Example 1 was dissolved in a mixed solvent (mixing ratio (weight ratio) = 5) of diisopentyl ether,? -Butyrolactone, N-methyl-2-pyrrolidone and butyl cellosolve : 30: 40: 25) to obtain a liquid crystal aligning agent having a solution viscosity of 6 mPa · s. This was filtered through a filter having a pore size of 0.2 mu m and then subjected to the following evaluation.

&Lt; Evaluation of inkjet application property &

As a substrate to which a liquid crystal aligning agent is applied, a glass substrate with a transparent electrode made of ITO is heated on a hot plate at 200 ° C for 1 minute and then subjected to ultraviolet / ozone cleaning to adjust the contact angle of water on the transparent electrode surface to 10 ° or less Were used.

The liquid crystal aligning agent (after filtration) prepared above was applied to the transparent electrode surface of the glass substrate to which the transparent electrode was attached using an ink jet applicator (Shibaura Mechatronics Co., Ltd.). At this time, the application conditions were two rounds of reciprocation (four times in total) at a discharge rate of 2,500 / (nozzle / minute) and a discharge rate of 250 mg / 10 second. After the application, the film was allowed to stand for one minute and then heated at 80 DEG C to form a coating film having an average film thickness of 0.1 mu m. The obtained coating film was observed with naked eyes under irradiation of an interference fringe measurement lamp (sodium lamp), and when no stain and elasticity were visible, the case where at least one of unevenness and elasticity was observed was defined as "good" The evaluation was evaluated as "defective ", and the inkjet application property of the liquid crystal aligning agent was" good ".

&Lt; Production of liquid crystal cell &

The liquid crystal cell for evaluating the liquid crystal alignment property and the voltage holding ratio was produced as follows. The application of the liquid crystal aligning agent in the production of the liquid crystal cell described below is in accordance with the spin coating method, but this makes it possible to make comparison with the comparative example which will be described later which is poor in inkjet application property.

The liquid crystal aligning agent (after filtration) prepared above was coated on the transparent electrode surface of a glass substrate with a transparent electrode containing an ITO film by spin coating, prebaked on a hot plate at 80 DEG C for 1 minute , And then baked on a hot plate at 200 DEG C for 10 minutes to form a coating film having an average film thickness of 0.1 mu m. The same operation was repeated to prepare two pairs of substrates having a liquid crystal alignment film on the transparent conductive film.

An epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 占 퐉 was applied to the outer edges of each of the pair of substrates having the liquid crystal alignment film, and then the liquid crystal alignment film faces were superimposed so as to oppose each other. Subsequently, a nematic liquid crystal (MLC-6601, 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 light-curing adhesive to prepare a liquid crystal cell.

<Evaluation of Liquid Crystal Alignment Property>

The liquid crystal cell prepared above was observed visually under the crossed Nicol polarized light, and when the light leakage was not observed, the liquid crystal alignment property was evaluated as "good ", and when the light leakage was observed, the liquid crystal alignment property was evaluated as & The liquid crystal alignment of the liquid crystal cell was "good ".

&Lt; Evaluation of voltage holding ratio &

A voltage of 5 V was applied to the liquid crystal cell obtained above 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 value was 95% or more, and the voltage holding ratio was evaluated as" bad "

&Lt; Example 2 >

Diisopentylether,? -Butyrolactone, N-methyl-2-pyrrolidone and butyl cellosolve were added to a solution containing the imidized polymer (PI-2) obtained in Synthesis Example 2, A liquid crystal aligning agent having a solution viscosity of 6 mPa · s and a diisopentyl ether:? -Butyrolactone: N-methyl-2-pyrrolidone: butyl cellosolve = 5: 30: . This was filtered with a filter having a pore size of 0.2 탆 and then evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

&Lt; Example 3 >

Diisopentylether, N-methyl-2-pyrrolidone and butyl cellosolve were added to a solution containing the imidized polymer (PI-3) obtained in Synthesis Example 3, and the solvent composition was diisopentyl ether: N-methyl-2-pyrrolidone: butyl cellosolve = 5: 50: 45 (weight ratio) and a solution viscosity of 6 mPa · s was prepared. This was filtered with a filter having a pore size of 0.2 탆 and then evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

<Example 4>

Diisopentyl ether, N-methyl-2-pyrrolidone and butyl cellosolve were added to a solution containing the imidized polymer (PI-4) obtained in Synthesis Example 4, and the solvent composition was diisopentyl ether: N-methyl-2-pyrrolidone: butyl cellosolve = 5: 50: 45 (weight ratio) and a solution viscosity of 6 mPa · s was prepared. This was filtered with a filter having a pore size of 0.2 탆 and then evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

&Lt; Comparative Example 1 &

Diisopentylether and N-methyl-2-pyrrolidone were added to a solution containing the imidized polymer (PI-3) obtained in Synthesis Example 3, and the solvent composition was diisopentylether: N-methyl- - pyrrolidone = 5: 95 (weight ratio), and a solution viscosity of 6 mPa · s was prepared. This was filtered with a filter having a pore size of 0.2 탆 and then evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

&Lt; Comparative Example 2 &

Butylolactone, N-methyl-2-pyrrolidone and butyl cellosolve were added to a solution containing the imidized polymer (PI-2) obtained in Synthesis Example 2, and the solvent composition was changed to butyrolactone: N- Methyl-2-pyrrolidone: butyl cellosolve = 40: 30: 30 and a solution viscosity of 6 mPa · s was prepared. This was filtered with a filter having a pore size of 0.2 탆 and then evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

Claims (6)

A liquid crystal aligning agent containing at least one polymer selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride and a diamine compound and a polyimide obtained by dehydration ring closure thereof, Solvent (A) a first solvent comprising a compound represented by the following formula (I)

(In the formula (I), each R is independently an alkyl group having 3 to 10 carbon atoms) (B) a group consisting of N-methyl-2-pyrrolidone,? -Butyrolactone, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylformamide and N, N- A second solvent comprising at least one selected from the group consisting of: (C) a third solvent comprising at least one member selected from the group consisting of butyl cellosolve, diacetone alcohol, propylene carbonate, diethylene glycol diethyl ether and ethyl-3-ethoxypropionate Wherein the liquid crystal aligning agent is a liquid crystal aligning agent. The method of claim 1, wherein the ratio of the first solvent (A) to the total amount of the first solvent (A), the second solvent (B), and the third solvent (C) Wherein the ratio of the second solvent is 10 to 94.5% by weight, and (C) the ratio of the third solvent is 5 to 70% by weight. The liquid crystal aligning agent according to claim 1 or 2, wherein the compound represented by the formula (I) has a boiling point of 140 to 200 ° C and a surface tension of 18 to 27 mN / m. The liquid crystal aligning agent according to claim 3, wherein the compound represented by the formula (I) is at least one selected from the group consisting of diamyl ether and diisopentyl ether. 3. The process according to claim 1 or 2, wherein the tetracarboxylic dianhydride is represented by the following formula (1)

(Wherein R ¹ is each independently a hydrogen atom, a chlorine atom or an alkyl group having 1 to 6 carbon atoms) , A compound represented by the following formula (2)

(Wherein R ² is each independently an alkyl group having 1 to 6 carbon atoms and n is an integer of 0 to 4) , Pyromellitic dianhydride, 1,2,4-tricarboxycyclopentylacetic acid dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,2,3,4-cyclopentanetetra A carboxylic acid dianhydride, and a 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride. A liquid crystal display element comprising a liquid crystal alignment film obtained from the liquid crystal alignment agent according to any one of claims 1 to 5.