JP2001081323A - Liquid crystal orienting agent and liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal orienting agent capable of exhibiting good printability and defoaming properties and forming a liquid crystal oriented film suitable for composing a liquid crystal display element by including at least one polymer selected from a polyamic acid and a polyimide and a specified solvent. SOLUTION: This liquid crystal orienting agent comprises (A) at least one polymer selected from the group consisting of (i) a polyamic acid prepared by reacting a tetracarboxylic dianhydride with a diamine compound represented by the formula (R1 is a 1-12C hydrocarbon; a is 1-3; b is 1-20) and (ii) a polyimide obtained by cyclodehydrating the component (i) and (B) a solvent containing N-methyl-2-pyrrolidone. The content of the component B is 5-90 wt.% based on the liquid crystal orienting agent. The liquid crystal display element can be obtained by using the resultant liquid crystal orienting agent and forming a liquid crystal oriented film. The obtained liquid crystal display element is excellent in orienting properties of liquid crystals and reliability and useful for various devices.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a liquid crystal aligning agent and a liquid crystal display device. More specifically, the present invention relates to a liquid crystal aligning agent excellent in printability and defoaming property, and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art At present, as a liquid crystal display device, a liquid crystal alignment film made of polyamic acid, polyimide or the like is formed on the surface of a substrate on which a transparent conductive film is provided to form a substrate for the liquid crystal display device. A nematic liquid crystal layer having a positive dielectric anisotropy is formed in the gap to form a cell having a sandwich structure, and the major axis of the liquid crystal molecules is continuously shifted from one substrate to the other substrate by 90%. So-called TN type (Twisted Nemati)
c) A TN type liquid crystal display device having a liquid crystal cell is known. In recent years, the ST has a higher contrast than the TN type liquid crystal display element and has less viewing angle dependence.
N (Super Twisted Nematic) type liquid crystal display devices and vertical alignment type liquid crystal display devices have been developed. This STN type liquid crystal display element uses a nematic type liquid crystal blended with an optically active substance, a chiral agent, as a liquid crystal, and the major axis of liquid crystal molecules is continuously twisted over 180 degrees between substrates. This utilizes the birefringence effect caused by the above. The vertical alignment type liquid crystal display element is, for example, one in which liquid crystal having negative dielectric anisotropy of liquid crystal molecules is vertically aligned, and the liquid crystal molecules are tilted down by application of a voltage to operate horizontally. Orientation of the liquid crystal in these liquid crystal display elements is usually exhibited by a rubbed liquid crystal alignment film.

[0003] The liquid crystal aligning agent used in such a liquid crystal display element is applied on a substrate by a method such as printing or spin coating. However, in the case of mass production, the printing method is often used. If unevenness occurs at the time of printing, the yield decreases, and thus an alignment agent having improved printability has been demanded. Further, there is a drawback that bubbles are generated by transporting the liquid crystal aligning agent or by bubbles during printing, resulting in deterioration of printability.

However, at present, there is no liquid crystal display element which sufficiently satisfies printability and defoaming property with a conventional liquid crystal aligning agent.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal aligning agent having good printability and defoaming properties. It is in. Still other objects and advantages of the present invention will become apparent from the following description.

[0006]

According to the present invention, the above objects and advantages of the present invention are as follows: (A) tetracarboxylic dianhydride and a compound represented by the following formula (1):

[0007]

Embedded image (Wherein, R ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ^{1 s} may be the same or different, a is an integer of 1 to 3, b is 1 to 20) Is an integer.)

A polyamic acid (hereinafter, also referred to as "polyamic acid (A)") obtained by reacting a diamine compound (hereinafter, also referred to as "organosiloxane diamine") represented by the following formula (B): It contains at least one polymer (hereinafter, also referred to as "specific polymer") selected from the group consisting of polyimides obtained by ring closure (hereinafter, also referred to as "polyimide (B)") and a solvent, and the solvent contains N -Methyl-2-pyrrolidone, wherein the content is 5 to 90% by weight based on the liquid crystal aligning agent.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. [Polyamic acid (A)] The polyamic acid (A) used in the present invention is obtained by ring-opening polyaddition of a tetracarboxylic dianhydride and an organosiloxane diamine. The polyimide (B) used in the present invention can be obtained by dehydrating and ring-closing the above polyamic acid (A).

<Tetracarboxylic dianhydride> Examples of the tetracarboxylic dianhydride used in the synthesis of the polyamic acid (A) include butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutane Tetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,
3,4-cyclobutanetetracarboxylic dianhydride, 1,3
-Dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,
4-cyclobutanetetracarboxylic dianhydride, 1,2,
3,4-cyclopentanetetracarboxylic dianhydride, 1,
2,4,5-cyclohexanetetracarboxylic dianhydride,
3,3 ′, 4,4′-dicyclohexyltetracarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5
-Diene-1,2,5,6-tetracarboxylic dianhydride,
2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 2,3,4,5-tetrahydrofurantetra Carboxylic dianhydride, 1,3,3
a, 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-2,5-
Dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-ethyl-5 (tetrahydro-2,5- Dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-methyl-5 (tetrahydro-2,5- Dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,
3-dione, 1,3,3a, 4,5,9b-hexahydro-
7-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 [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8- Ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione;
1,3,3a, 4,5,9b-Hexahydro-5,8-dimethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3- Zeon,
5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2,2,2] -oct-7-ene-2,
Aliphatic and alicyclic tetracarboxylic dianhydrides such as 3,5,6-tetracarboxylic dianhydride, compounds represented by the following formulas (2) and (3);

[0011]

Embedded image (Wherein, R ² and R ⁴ represent a divalent organic group having an aromatic ring, R ³ and R ⁵ represent a hydrogen atom or an alkyl group, and a plurality of R ³ and R ⁵ are the same. But may be different.)

Pyromellitic dianhydride, 3,3 ', 4,
4'-benzophenonetetracarboxylic dianhydride, 3,
3 ', 4,4'-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3 , 3 ', 4,4'-biphenylethertetracarboxylic dianhydride, 3,3', 4,4'-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ', 4,
4′-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride,
4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfone dianhydride,
4,4′-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidene diphthalic dianhydride, 3,3 ′,
4,4′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride,
p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether dianhydride, bis ( (Triphenylphthalic acid) -4,4'-diphenylmethane dianhydride, ethylene glycol-bis (anhydrotrimellitate), propylene glycol-bis (anhydrotrimellitate), 1,4-butanediol-bis (anne Hydrotrimellitate), 1,6-hexanediol-bis (anhydrotrimellitate), 1,8-octanediol-
Bis (anhydrotrimellitate), 2,2-bis (4
-Hydroxyphenyl) propane-bis (anhydrotrimellitate) and aromatic tetracarboxylic dianhydrides such as compounds represented by the following formulas (4) to (7). These are used alone or in combination of two or more.

[0013]

Embedded image

Of these, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride Anhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5- (2,5-dioxotetrahydrofural) -3-methyl -3-cyclohexene-1,2-dicarboxylic dianhydride, cis-3,7
-Dibutylcycloocta-1,5-diene-1,2,5,6
-Tetracarboxylic dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 1,3,3a, 4,5,9b-hexahydro-5-
(Tetrahydro-2,5-dioxo-3-furanyl)-
Naphtho [1,2-c] furan-1,3-dione, 1,3,3
a, 4,5,9b-Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3, 3a,
4,5,9b-Hexahydro-5,8-dimethyl-5-
(Tetrahydro-2,5-dioxo-3-furanyl)-
Naphtho [1,2-c] furan-1,3-dione, bicyclo [2,2,2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, pyromellitic dianhydride Anhydride, 3,
3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride A compound represented by the following formulas (8) to (10) among the compounds represented by the above formula (2) and a compound represented by the following formula (11) among the compounds represented by the above formula (II) Is preferred from the viewpoint that good liquid crystal alignment can be exhibited, and particularly preferred are 1, 2, and
3,4-cyclobutanetetracarboxylic dianhydride, 1,3
-Dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- ( Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione;
Cis-3,7-dibutylcycloocta-1,5-diene-
1,2,5,6-tetracarboxylic dianhydride, 3,5,6-
Tricarbonyl-2-carboxynorbornane-2:
3,5: 6-dianhydride, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2- c] Furan-1,3-dione, pyromellitic dianhydride and a compound represented by the following formula (8).

[0015]

Embedded image

<Organosiloxane Diamine> The organosiloxane diamine used in the synthesis of the polyamic acid (A) is represented by the above formula (1). As such organosiloxane diamine, for example, 1,3-bis (1
-Aminomethyl) -1,1,3,3-tetramethyldisiloxane, 1,3-bis (2-aminoethyl) -1,1,3,
3-tetramethyldisiloxane, 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane, 1,3-bis (4-aminobutyl) -1,1,3, 3
-Tetramethyldisiloxane, 1,5-bis (3-aminopropyl) -1,1,3,3,5,5-hexamethyltrisiloxane, 1,3-bis (3-aminopropyl) -1,
1,3,3-tetraethyldisiloxane, 1,3-bis (3-aminopropyl) -1,1,3,3-tetrapropyldisiloxane, 1,3-bis (3-aminopropyl)
-1,1,3,3-tetraphenyldisiloxane, 1,7-
Bis (3-aminopropyl) -1,1,3,3,5,5,7,
7-octamethyltetrasiloxane and the like can be mentioned. These can be used alone or in combination of two or more.

<Diamine Compounds Other than Organosiloxane Diamine> In the synthesis of the polyamic acid (A), other diamine compounds can be used in addition to the organosiloxane diamine. Further, the liquid crystal alignment agent of the present invention, in addition to the specific polymer using an organosiloxane diamine, obtained from other diamine and tetracarboxylic dianhydride without using an organosiloxane diamine, other than the specific polymer Other polyamic acids and / or
Alternatively, a polyimide can be used in combination.

The other diamines include, 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-diaminonaphthalene, 3,3
-Dimethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4'-aminophenyl) -1, 3,3-trimethylindane, 3,4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-
Diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-amino Phenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4
-Aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, , 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, 4,4'-(p-
(Phenyleneisopropylidene) bisaniline, 4,4 '
-(M-phenyleneisopropylidene) bisaniline,
2,2'-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl, 4,4 '-Bis [(4-amino-
Aromatic diamines such as 2-trifluoromethyl) phenoxy] -octafluorobiphenyl;

1,1-metaxylylenediamine, 1,3-
Propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine,
1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine,
Aliphatic and alicyclic diamines such as hexahydro-4,7-methanoindanylene dimethylene diamine, tricyclo [6.2.1.0 ^2,7 ] -undecylene dimethyl diamine, 4,4'-methylene bis (cyclohexylamine) ;

2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino- 2,4-dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5
-Triazine, 1,4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,
3,5-triazine, 2,4-diamino-6-methoxy-
1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl-s-triazine, 2,4-diamino-1,3, 5-
Triazine, 4,6-diamino-2-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-ethoxyacridine lactate, 3,8- Diamino-6-phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine and compounds represented by the following formulas (12) to (13), A diamine having two primary amino groups and a nitrogen atom other than the primary amino group in the molecule;

[0021]

Embedded image

Wherein R ⁶ is pyridine, pyrimidine,
X represents a monovalent organic group having a ring structure containing a nitrogen atom selected from triazine, piperidine and piperazine;
Represents a divalent organic group. )

[0023]

Embedded image (Wherein R ⁷ is pyridine, pyrimidine, triazine,
X represents a divalent organic group having a ring structure containing a nitrogen atom selected from piperidine and piperazine; X represents a divalent organic group; and a plurality of Xs may be the same or different. )

A monosubstituted phenylenediamine represented by the following formula (14):

Embedded image (Wherein, R ⁸ represents —O—, —COO—, —OCO—,
R9 represents a divalent organic group selected from NHCO-, -CONH- and -CO-, and R9 is a monovalent organic group having a steroid skeleton, a trifluoromethyl group or a group selected from a fluoro group, or a C6-C6 group. And represents 30 alkyl groups. )

Examples include compounds represented by the following formulas (15) to (19). These diamine compounds can be used alone or in combination of two or more.

[0026]

Embedded image (In the formula, y is an integer of 2 to 12, and z is an integer of 1 to 5.)

Of these, p-phenylenediamine,
4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4'-diaminodiphenylether, 2,2-bis [4- (4- Aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-
Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '-(p-phenylenediisopropylidene) bisaniline, 4,4'-(m-phenylenediisopropyl Riden) bisaniline, 1,4-cyclohexanediamine, 4,4′-methylenebis (cyclohexylamine), 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, Compounds represented by formulas (15) to (19),
2,6-diaminopyridine, 3,4-diaminopyridine,
2,4-diaminopyrimidine, 3,6-diaminoacridine, among the compounds represented by the above formula (12), the following formula (2
0), compounds represented by the above formula (13), compounds represented by the following formula (21), and compounds represented by the above formula (14); 2
The compound represented by 7) is preferred.

[0028]

Embedded image

The ratio of the organosiloxane diamine to the total diamine component in the total polymer contained in the liquid crystal aligning agent of the present invention is 0.1 to 0.1 relative to the total amount of the diamine component.
50% by weight is preferred. When the use ratio is less than 0.1% by weight, a sufficient effect for improving printability and defoaming property may not be obtained. If it exceeds 50% by weight, the liquid crystal alignment of the obtained liquid crystal alignment agent may be reduced.

<Synthesis of Polyamic Acid (A)> The proportions of the tetracarboxylic dianhydride, the organosiloxane diamine, and the other diamine compound used in the synthesis reaction of the polyamic acid (A) are as follows. The acid anhydride group of tetracarboxylic dianhydride is 0.2 to 1 equivalent of the amino group of the diamine compound other than the above.
The ratio is preferably 2 to 2 equivalents, more preferably 0.1 equivalent.
It is a ratio of 3 to 1.2 equivalents. The synthesis reaction of the polyamic acid (A) is usually carried out in an organic solvent at -20.
C. to 150.degree. C., preferably 0 to 100.degree. Here, the organic solvent is not particularly limited as long as it can dissolve the polyamic acid (A) to be synthesized. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide ,
Examples include aprotic polar solvents such as dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, and hexamethylphosphortriamide; and phenol solvents such as m-cresol, xylenol, phenol, and halogenated phenol. The amount of the organic solvent used (α) is usually the total amount of the tetracarboxylic dianhydride and the diamine compound (β), and the total amount of the reaction solution (α + β).
It is preferable that the amount is 0.1 to 30% by weight based on the total weight.

The organic solvent includes a polyamic acid which produces alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc., which are poor solvents for the polyamic acid (A). They can be used together as long as they do not precipitate. Specific examples of such a poor solvent include:
For example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol,
Propylene glycol, 1,4-butanediol, 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 , Ethyl ethoxypropionate,
Diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol Ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-
Dichlorobutane, trichloroethane, chlorobenzene,
Examples thereof include o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, and xylene.

As described above, the polyamic acid (A)
To obtain a reaction solution. Then, the reaction solution is poured into a large amount of a poor solvent to obtain a precipitate, and the precipitate is dried under reduced pressure to obtain a polyamic acid (A). In addition, the polyamic acid (A) can be purified by dissolving the polyamic acid again in the organic solvent and then performing the step of precipitating with the poor solvent once or several times.

<Synthesis of Polyimide (B)> The polyimide (B) constituting the liquid crystal aligning agent of the present invention can be synthesized by dehydrating and ring-closing the above polyamic acid (A). The dehydration and ring closure of the polyamic acid (A) can be performed by (i) a method of heating the polyamic acid (A) or (ii)
The method is carried out by dissolving the polyamic acid (A) in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst to the solution, and heating as necessary. The polyimide (B) used in the present invention has a partially dehydrated and ring-closed imidization ratio (the percentage of the repeating unit forming an imide ring in all repeating units in the polymer is represented by%. Less than 100%) may be contained.

The reaction temperature in the method (i) of heating the polyamic acid (A) is usually from 50 to 200 ° C., preferably from 60 to 170 ° C. Reaction temperature 5
When the reaction temperature is lower than 0 ° C, the dehydration ring-closing reaction does not sufficiently proceed, and when the reaction temperature exceeds 200 ° C, the molecular weight of the obtained polyimide (B) may decrease.

On the other hand, the polyamic acid (A) of the above (ii)
In the method of adding a dehydrating agent and a dehydration ring-closing catalyst to the above solution, as the dehydrating agent, for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably 0.01 to 20 mol per 1 mol of the repeating unit of the polyamic acid (A). In addition, as a dehydration ring closure catalyst,
For example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used. However, it is not limited to these. The amount of the dehydration ring-closing catalyst used is preferably 0.01 to 10 mol per 1 mol of the dehydrating agent used. In addition, as the organic solvent used for the dehydration ring closure reaction, the organic solvents exemplified as those used for the synthesis of the polyamic acid (A) can be mentioned. The reaction temperature of the dehydration ring closure reaction is usually 0 to 18
0 ° C, preferably 10 to 150 ° C. The polyimide (B) can be purified by subjecting the reaction solution thus obtained to the same operation as the method for purifying the polyamic acid (A).

<Terminal-Modified Polymer> The polyamic acid (A) and the polyimide (B) may be terminal-modified polymers having a controlled molecular weight. By using this terminal-modified polymer, the coating characteristics of the liquid crystal aligning agent can be improved without impairing the effects of the present invention. Such a terminal-modified type can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound, or the like to the reaction system when synthesizing the polyamic acid (A). Here, as the acid monoanhydride, for example, 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, for example, aniline, cyclohexylamine, n
-Butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-
Nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-
Examples thereof include tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, and n-eicosylamine. In addition, examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

<Logarithmic Viscosity of Polyamic Acid (A)> The polymer (A) obtained as described above preferably has a logarithmic viscosity (η _ln ) value of 0.05 to 10 dl / g, more preferably 0.05 to 5 dl / g. The value of the logarithmic viscosity (η _ln ) in the present invention is obtained by measuring the viscosity of a solution having a concentration of 0.5 g / 100 ml at 30 ° C. using N-methyl-2-pyrrolidone as a solvent.
It is determined by the following equation (i).

[0038]

(Equation 1)

[Organic Solvent Used for Liquid Crystal Alignment Agent] The liquid crystal alignment agent of the present invention accounts for 5 to 90% by weight, preferably 10 to 90% by weight of N-methyl-2-based on the whole liquid crystal alignment agent.
It contains pyrrolidone and must contain a solvent other than N-methyl-2-pyrrolidone. When the content of N-methyl-2-pyrrolidone is large, the water absorbing property of the liquid crystal aligning agent is increased, and the solubility of the dissolved polyamic acid and / or polyimide may be reduced to facilitate precipitation. If the amount is too small, foaming during transport and printing is likely to occur, and the printability may decrease.

As the organic solvent constituting the liquid crystal aligning agent of the present invention, in addition to N-methyl-2-pyrrolidone, other good solvents exemplified as those used in the synthesis reaction of the polyamic acid (A) are used in combination. be able to. In addition, the poor solvents exemplified as those which can be used together in the synthesis reaction of the polyamic acid (A) can be appropriately selected and used in combination. Good solvents other than N-methyl-2-pyrrolidone are preferably used in a range of 1 to 94 parts by weight or less per 100 parts by weight of the whole liquid crystal aligning agent.

[Liquid Crystal Alignment Agent] The liquid crystal alignment agent of the present invention is a polyamic acid (A) and / or polyamic acid (A) obtained by reacting tetracarboxylic dianhydride and an organosiloxane diamine of the formula (1). Is dissolved and contained in N-methyl-2-pyrrolidone. The liquid crystal aligning agent of the present invention further comprises another polyamic acid (C) containing no organosiloxane diamine as another component and / or another polyimide obtained by dehydrating and ring-closing another polyamic acid (C). D) can be contained. The other polyamic acid (C) and / or other polyimide (D) is preferably in a range of 95 parts by weight or less based on 100 parts by weight of polyamic acid (A) or / and polyimide (B).

The solid content concentration in the present invention is selected in consideration of viscosity, volatility, etc., and is preferably in the range of 1 to 10% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface to form a coating film serving as a liquid crystal aligning film. When the solid content concentration is less than 1% by weight,
In some cases, the film thickness of this coating film is too small to obtain a good liquid crystal alignment film, and when the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes excessively good. In some cases, it is difficult to obtain a liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent is increased, resulting in poor coating characteristics.

The liquid crystal aligning agent of the present invention may contain a functional silane-containing compound from the viewpoint of improving the adhesion to the substrate surface. Such functional silane-containing compounds include, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,
Aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3
-Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltri Methoxysilane, N-
Ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 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-benzyl-3
-Aminopropyltriethoxysilane, N-phenyl-
3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxy Examples include silane. The mixing ratio of these functional silane-containing compounds is as follows:
It is usually 40 parts by weight or less, preferably 0.1 to 30 parts by weight with respect to 0 parts by weight.

[Liquid crystal display device] A liquid crystal display device obtained by using the liquid crystal aligning agent of the present invention can be produced, for example, by the following method.

(1) The liquid crystal aligning agent of the present invention is applied to one surface of a substrate on which a patterned transparent conductive film is provided, for example, by a roll coater method, a spinner method, a printing method or the like, and then the coated surface Is heated to form a coating film. Here, as the substrate, for example, a transparent substrate made of glass such as float glass or soda glass; or a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, or polycarbonate can be used. As the transparent conductive film provided on one surface of a substrate, NESA film (US PPG registered trademark) made of tin oxide (SnO _2), indium oxide - IT consisting of tin oxide (In ₂ O ₃ -SnO ₂₎
An O film or the like can be used. A photo-etching method or a method using a mask in advance is used for patterning these transparent conductive films. In applying the liquid crystal aligning agent, a functional silane-containing compound, a functional titanium-containing compound, etc. are applied in advance to the substrate surface and the surface of the substrate in order to further improve the adhesion between the transparent conductive film and the coating film. You can also. Heating temperature after application of liquid crystal aligning agent is 80 ~ 3
The temperature is set to 00 ° C, preferably 120 to 250 ° C.
The liquid crystal aligning agent of the present invention containing a polyamic acid forms a coating film to be an alignment film by removing the organic solvent after coating, but further heated to promote dehydration ring closure and imidization. It can also be a coating film. The thickness of the formed coating film is preferably 0.001.
１1 μm, more preferably 0.005 to 0.5 μm
It is.

(2) A rubbing treatment is performed in which the formed coating film surface is rubbed in a certain direction with a roll around which a cloth made of fibers such as nylon, rayon, cotton or the like is wound. Thereby, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film.

Further, the liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention is partially irradiated with ultraviolet rays as disclosed in, for example, JP-A-6-222366 and JP-A-6-281937. To change the pretilt angle by changing the pre-tilt angle.
No. 544, a resist film is partially formed on the surface of the rubbed liquid crystal alignment film, and the resist film is removed after performing a rubbing process in a direction different from the previous rubbing process. By performing a process for changing the liquid crystal alignment ability of the liquid crystal alignment film, the visibility characteristics of the liquid crystal display element can be improved.

(3) Two substrates on which a liquid crystal alignment film is formed as described above are prepared, and the two substrates are separated by a gap so that the rubbing directions of the respective liquid crystal alignment films are orthogonal or antiparallel. (Cell gap)
The peripheral portions of the two substrates are bonded to each other using a sealant, and liquid crystal is injected and filled into the substrate surface and a cell gap defined by the sealant, and the injection hole is sealed to form a liquid crystal cell. Then, a polarizing plate is provided on the outer surface of the liquid crystal cell, that is, on the other surface side of each substrate constituting the liquid crystal cell, and the polarization direction thereof coincides with or is orthogonal to the rubbing direction of the liquid crystal alignment film formed on one surface of the substrate. Thus, a liquid crystal display element is obtained.

Here, as the sealant, for example, an epoxy resin containing aluminum oxide spheres 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, for example, a Schiff base liquid crystal, an azoxy liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, an ester liquid crystal, a terphenyl liquid crystal, a biphenylcyclohexane liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, and bicyclooctane. Liquid crystal, cubane liquid crystal, or the like can be used. In addition, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonaate, and cholesteryl carbonate, and chiral agents such as those sold under the trade names "C-15" and "CB-15" (manufactured by Merck & Co.) It can also be used by adding it. In addition, ferroelectric liquid crystals such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate can be used.

The polarizing plate to be bonded to the outer surface of the liquid crystal cell is a polarizing plate in which a polarizing film called an H film absorbing iodine is sandwiched between cellulose acetate protective films while stretching and aligning polyvinyl alcohol. Alternatively, a polarizing plate composed of the H film itself can be used.

[0051]

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

Synthesis Example 1 2,2.4 g (100 mmol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride and 1,5-g as organosiloxane diamine
1.3 g (5 mmol) of bis (1-aminomethyl) -1,1,3,3,5,5-hexamethyltrisiloxane and 8.9 g of 4,4'-diaminodiphenylmethane as a diamine other than organosiloxane diamine (45 mmol), 26 g of a diamine represented by the above chemical formula (22)
(50 mmol) was added to N-methyl-2-pyrrolidone 45
0 g, and reacted at 60 ° C. for 6 hours. Then
The reaction solution was poured into a large excess of methyl alcohol to precipitate a reaction product. After that, wash with methyl alcohol,
After drying under reduced pressure at 40 ° C. for 15 hours, a polyamic acid using organosiloxane diamine having an logarithmic viscosity of 0.95 dl / g and an imidation ratio of 0% (this is referred to as “polyamic acid (A-1)”) 56. 8 g were obtained.

Synthesis Example 2 As a diamine other than the organosiloxane diamine, p-
9.2 g (85 mmol) of phenylenediamine and 5.2 g (10 mmol) of the diamine represented by the above chemical formula (22) were used, and the reaction time was changed to 60 ° C. for 5 hours. 34.5 g of a polyamic acid using an organosiloxane diamine having a logarithmic viscosity of 0.94 dl / g and an imidation ratio of 0% was obtained. 25.0 g of the obtained polyamic acid was mixed with 450 g of N-methyl-2-pyrrolidone.
, 7.0 g of pyridine and 9.1 g of acetic anhydride were added, and a dehydration ring closure reaction was performed at 100 ° C. for 3 hours. Next, the reaction solution was precipitated, washed and dried in the same manner as in Synthesis Example 1 to obtain an organosiloxane-based polyimide having an inherent viscosity of 0.95 dl / g and an imidation ratio of 70% (this was referred to as “polyimide (B-1)”). 20.0 g was obtained.

Synthesis Example 3 In Synthesis Example 2, 7.6 g of p-phenylenediamine was used.
(70 mmol) and 13 g (25 mmol) of the diamine represented by the above chemical formula (22).
Except that the temperature was changed to 1 hour, the same procedure as in Synthesis Example 2 was repeated except that a polyimide using organosiloxane having an logarithmic viscosity of 0.65 dl / g and an imidation ratio of 68% (this was referred to as “polyimide (B-
2) ". 2) g were obtained.

Synthesis Example 4 In Synthesis Example 3, 1,5-bis (1-aminomethyl)
4.0 g (15 mmol) of -1,1,3,3,5,5-hexamethyltrisiloxane, p-phenylenediamine 6.
5 g (60 mmol) and 13 g (25 mmol) of the diamine represented by the above chemical formula (22), except that the organosilicon had a logarithmic viscosity of 0.64 dl / g and an imidation ratio of 69% in the same manner as in Synthesis Example 3. 20.8 g of a siloxane-based polyimide (hereinafter referred to as "polyimide (B-3)") was obtained.

Synthesis Example 5 In Synthesis Example 2, tetracarboxylic dianhydride was converted to cis-
3,7-dibutylcycloocta-1,5-diene-1,2,
Except that 3,6-g (100 mmol) of 5,6-tetracarboxylic dianhydride was used, the logarithmic viscosity was set to 0.3 in the same manner as in Synthesis Example 2.
20.1 g of a polyimide containing 90 dl / g and an imidization ratio of 70% using an organosiloxane (hereinafter referred to as "polyimide (B-4)") was obtained.

Synthesis Example 6 In Synthesis Example 2, the tetracarboxylic dianhydride was replaced with 3,5,6
-Tricarbonyl-2-carboxynorbornane-2:
Except that 25.0 g (100 mmol) of 3,5: 6-dianhydride was used, the logarithmic viscosity was 0.98 dl /
g, a polyimide containing an organosiloxane having an imidation ratio of 73% (this is referred to as “polyimide (B-5)”).
9.8 g were obtained.

Synthesis Example 7 In Synthesis Example 1, 9.9 g (5,4 ′) of 4,4′-diaminodiphenylmethane was used without using an organosiloxane diamine.
0 mmol), and an organosiloxane diamine-free polyamic acid having a logarithmic viscosity of 0.95 dl / g and an imidation ratio of 0% (this was referred to as “polyamic acid (C-1)”). 55.8 g was obtained.

Synthesis Example 8 As the tetracarboxylic dianhydride, 10.9 g (50 mmol) of pyromellitic dianhydride, 9.8 g (50 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 20 g of 4,4'-diaminodiphenyl ether as diamine other than organosiloxane diamine
(100 mmol) was used. Otherwise in the same manner as in Synthesis Example 1, 50.0 g of an organosiloxanediamine-free polyamic acid having a logarithmic viscosity of 1.45 dl / g (hereinafter referred to as “polyamic acid (C-2)”) was obtained.

Synthesis Example 9 The same procedure as in Synthesis Example 2 was carried out except that the organosiloxane diamine was not used and p-phenylenediamine was changed to 9.7 g (90 mmol). g, and 19.9 g of an organosiloxane diamine-free polyimide having an imidation ratio of 68% (hereinafter referred to as "polyimide (D-1)").

Synthesis Example 10 In Synthesis Example 3, 8.1 g (75 mmol) of p-phenylenediamine was used without using an organosiloxane diamine.
Except that the logarithmic viscosity was set to 0.3 in the same manner as in Synthesis 3.
69 dl / g, 71% imidization ratio organosiloxane diamine-free polyimide (this is referred to as "polyimide (D-
2) ". 2) g were obtained.

Example 1 (1) Preparation of liquid crystal aligning agent: 5 g of the polyamic acid (A-1) obtained in Synthesis Example 1 was mixed with 25 g of N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2. -Dissolved in a mixed solvent with 70 g of pentanone to obtain a solid content of 5% by weight
Solution. This solution was filtered through a filter having a pore size of 1 μm to prepare a liquid crystal aligning agent of the present invention. (2) Evaluation of printability: The liquid crystal aligning agent of the present invention prepared as described above was printed on a transparent conductive substrate composed of an ITO film using a printing machine for coating a liquid crystal alignment film, and a coating film of 800 Å was formed. Was formed. The printed coated surface was visually checked, and it was confirmed that there was no unevenness and the printability was good. (3) Evaluation of defoaming property 10 ml of the liquid crystal aligning agent of the present invention was poured into a glass sample bottle having a capacity of 20 ml containing a rotor, and stirred at 500 rpm for 10 minutes using a magnetic stirrer. After the sample bottle was allowed to stand for 10 minutes, the presence or absence of bubbles in the liquid crystal aligning agent was visually observed. Those in which no bubbles were observed were regarded as having good defoaming properties, and those in which they were observed were regarded as having poor printability. In Example 1, no foam was observed and the defoaming property was good.

Examples 2 to 6 The polyamic acid and / or polyimide obtained in Synthesis Examples 1 to 10 and N-methyl-2-pyrrolidone and other organic solvents were used according to the formulation shown in Table 1 below. The liquid crystal aligning agent of the present invention was prepared in the same manner as described above, and the printability and the defoaming property were evaluated. Both printability and defoamability were good. The results are shown in Table 1.

Comparative Examples 1 to 4 According to the formulation shown in Table 1 below, the polyamic acid and / or polyimide obtained in Synthesis Examples 1 to 10, N-methyl-2-pyrrolidone and other organic solvents were used. The liquid crystal aligning agent of the present invention was prepared in the same manner as described above, and the printability and the defoaming property were evaluated. In Comparative Examples 1 to 3, unevenness occurred on the printed application surface, and the printability was poor. The defoaming properties were also poor. In Comparative Example 4, although a large amount of N-methyl-2-pyrrolidone was added and the defoaming property was good, the liquid crystal aligning agent became cloudy at the time of printing, making printing impossible. The results are shown in Table 1.

[0065]

[Table 1]

[0066]

According to the present invention, it is possible to provide a liquid crystal aligning agent having excellent printability and defoaming properties. The liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention can be used not only for TN type liquid crystal display elements and STN type liquid crystal display elements but also for SH (Super
It can be suitably used for constructing various liquid crystal display elements such as an (rhomeotropic) type liquid crystal display element. Further, the liquid crystal display device provided with the liquid crystal alignment film has excellent liquid crystal alignment and reliability, and can be effectively used for various devices. For example, a desk calculator, a wristwatch, a clock, a counting display, a word processor It can be suitably used as a display device such as a personal computer and a liquid crystal television.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Keiichi Yamamoto F-term (reference) 2J090 HB08Y HB09Y HB10Y HC06 KA04 MB01 4J002 CM04W CM04X FD206 GP00 4J043 PA02 QB26 QB31 RA34 SA06 SA43 SA44 SA47 SA49 SA52 SA54 SA63 SA72 SA85 SB01 SB03 TA02 TA09 TA22 TA43 TA67 TA68 TA71 TB01 TB03 UA022 UA032 UA041 UA042 UA051 UA052 UA061 UA062 UA082 UA121 UA121 UA1 UA UA UA UA UA UA UA UA UA UA UA UA UB011 UB021 UB022 UB061 UB062 UB121 UB122 UB132 UB151 UB152 UB221 UB281 UB282 UB301 UB302 UB312 UB382 VA021 VA031 VA041 ZB23

Claims (2)

[Claims] (A) Tetracarboxylic dianhydride and the following formula (1) (Wherein, R ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ^{1 s} may be the same or different, a is an integer of 1 to 3, b is 1 to 20) At least one polymer selected from the group consisting of a polyamic acid obtained by reacting a diamine compound represented by the formula (I) and (B) a polyimide obtained by dehydrating and cyclizing the polyamic acid, and a solvent. And the solvent is N-
A liquid crystal aligning agent comprising methyl-2-pyrrolidone, the content of which is 5 to 90% by weight based on the liquid crystal aligning agent. 2. A liquid crystal display device comprising a liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 1.