JP2001305549A - Aligning agent for liquid crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a perpendicular aligning agent for a liquid crystal from which an alignment film for a liquid crystal showing good perpendicular aligning property of the liquid crystal and having high voltage holding characteristics, low residual DC voltage and excellent printing property can be formed. SOLUTION: The perpendicular aligning agent for a liquid crystal contains polyamic acid and a polyimide which has organic groups having a steroid skeleton derived from diamine by at least 10% of the repeating unit and has >=40% imidization degree.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a liquid crystal aligning agent. More specifically, the present invention relates to a novel liquid crystal alignment agent excellent in vertical alignment, voltage holding characteristics, low residual DC, and printability.

[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 addition, the STN (Super) has a higher contrast than the TN type liquid crystal display element and has a small viewing angle dependency.
Twisted Nematic) type liquid crystal display device,
A vertical alignment type liquid crystal display device has been developed. This STN
-Type liquid crystal display device uses nematic liquid crystal blended with a chiral agent that is an optically active substance as liquid crystal,
The birefringence effect produced by the state where the major axis of the liquid crystal molecules is continuously twisted over 180 degrees between the substrates is used.

On the other hand, a vertical alignment type liquid crystal display element vertically aligns a liquid crystal having negative dielectric anisotropy of liquid crystal molecules, tilts the liquid crystal molecules by applying a voltage, and operates the liquid crystal molecules horizontally. It is excellent in terms of contrast, rubbing-less, and the like, and has been actively studied in recent years. A high pretilt angle is required for vertical alignment,
It is necessary to include a large amount of a component for expressing a pretilt angle in the alignment agent. In the pretilt expression component, usually,
Aliphatic, alicyclic, and fluorine-based functional groups are often used.

[0004] However, this causes a problem that aggregation or crystallization of the pretilt angle developing components occurs, thereby deteriorating printability. Therefore, development of a liquid crystal aligning agent which is excellent in printability and satisfies vertical alignment, low image persistence, and voltage holding characteristics is desired. The present invention has been made based on the above circumstances.

[0005]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a liquid crystal aligning agent having good vertical alignment, low residual DC, voltage holding characteristics, and printability. Still 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 as follows: (A) The following formula (1)

[0006]

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Here, R ¹ is a tetravalent organic group and R ² is a divalent organic group, and a polyamic acid having a repeating unit represented by the following formula: At least one polymer selected from the group consisting of the obtained imidized polymers (hereinafter also referred to as “component (A)”), and (B)
The following equation (2)

[0008]

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Here, R^ThreeIs a tetravalent organic radical and
R^FourIs a divalent organic group, provided that R ^FourAt least
10 mol% is a divalent organic compound represented by the following formula (2-1).
Group,

[0010]

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Here, R ⁵ is an alkyl group having 10 to 20 carbon atoms or a monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms, and X is a divalent organic group. The imidization ratio obtained by at least partially dehydrating and cyclizing a polyamic acid having a repeating unit is 40%.
This is achieved by a liquid crystal aligning agent containing the above imidized polymer (hereinafter, also referred to as “component (B)”).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

Polyamic Acid The polyamic acid used as the component (A) is obtained by ring-opening polyaddition of a tetracarboxylic dianhydride and a diamine. The imidized polymer used as the component (A) and the component (B) is obtained by at least partially dehydrating and ring-closing the polyamic acid.

<Tetracarboxylic dianhydride> Examples of the tetracarboxylic dianhydride used in the synthesis of the polyamic acid include aliphatic tetracarboxylic dianhydrides such as butanetetracarboxylic dianhydride and 1, 2,3,4-
Cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride Product, 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 dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,
5: 6-dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,3,3a, 4,5,9b-
Hexahydro-5 (tetrahydro-2,5-dioxo-
3-furanyl) -naphtho [1,2-c] -furan-1,3
-Dione, 1,3,3a, 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, 3
a, 4,5,9b-Hexahydro-5,8-dimethyl-5
(Tetrahydro-2,5-dioxo-3-furanyl)-
Naphtho [1,2-c] -furan-1,3-dione, 5-
(2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2,2,2] -oct-7-ene-2,3,
5,6-tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride such as compounds represented by the following formulas (3) and (4);

[0015]

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(Wherein R ⁷ and R ^{9 each} represent a divalent organic group having an aromatic ring, R ⁶ and R ^{8 each} represent a hydrogen atom or an alkyl group, and a plurality of R ⁷ and R ⁹ represent May be the same or 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'-tetraphenylsilane Tetracarboxylic 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 (anhydrotrimellitate),
1,6-hexanediol-bis (anhydrotrimellitate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate) Melitate) and aromatic tetracarboxylic dianhydrides such as compounds represented by the following formulas (5) to (8).
These are used alone or in combination of two or more.

[0017]

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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 And compounds represented by the following formulas (9) to (11) among the compounds represented by the above formula (3) and compounds represented by the following formula (12) among the compounds represented by the above formula (4) Is preferred from the viewpoint that good liquid crystal alignment can be exhibited. Particularly preferred are 1, 2,
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 the compound represented by the above formula (9).

[0019]

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The component (A) used in the present invention comprises:
Those in which 50 mol% or more of R ¹ in the formula (1) are alicyclic are preferred from the viewpoint of low residual DC and voltage holding characteristics. Such a component (A) can be obtained by using an alicyclic tetracarboxylic dianhydride as a tetracarboxylic dianhydride in an amount of 50 mol% or more.

<Diamine> Examples of the diamine used in the synthesis of the above polyamic acid include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, and 4,4 ′. -Diaminodiphenyl sulfide, 4,4 '
-Diaminodiphenyl sulfone, 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-bis (4-aminophenyl) 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, 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 '-(p-phenyleneisopropylidene) bisaniline, 4,4'-(m-phenyleneisopropylidene) bisaniline, 2,2'-bis [4- (4-amino-2-triene Fluoromethylphenoxy) phenyl] hexafluoropropane, 4,4'-
Aromatic diamines such as diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl; 1,1-meta Xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1,4-diaminocyclohexane , Isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene dimethylenediamine, tricyclo [6.2.1.
Aliphatic and cycloaliphatic diamines such as 0 ^2,7 ] -undecylenedimethyldiamine, 4,4′-methylenebis (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 diamines having two primary amino groups and a nitrogen atom other than the primary amino groups in the molecule, such as compounds represented by the following formulas (13) to (15):

[0022]

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Wherein R ¹⁰ 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. )

[0024]

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Wherein R ¹¹ is pyridine, pyrimidine,
X represents a divalent organic group having a ring structure containing a nitrogen atom selected from triazine, piperidine and piperazine;
Represents a divalent organic group, and a plurality of Xs may be the same or different. A diaminoorganosiloxane represented by the following formula (15):

[0026]

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(Wherein R ¹² represents a hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ¹² may be the same or different, p is an integer of 1 to 3, and q is 1-2
It is an integer of 0. Examples include compounds represented by the following formulas (16) to (20). These diamine compounds can be used alone or in combination of two or more.

[0028]

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(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'- Diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 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-phenylenediisopropylidene) bisaniline, 1,4-cyclohexanediamine, 4,4′-methylenebis (cyclohexylamine), 1, 4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, a compound represented by the above formulas (16) to (20),
6-diaminopyridine, 3,4-diaminopyridine, 2,
4-diaminopyrimidine, 3,6-diaminoacridine, among the compounds represented by the above formula (13), the following formula (2)
Among the compound represented by 1) and the compound represented by the above formula (14), a compound represented by the following formula (22) is preferable.

[0030]

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The component (B) used in the present invention,
The doped polymer is represented by R in the above formula (2). ^FourAt least
10 mol% is a divalent organic compound represented by the above formula (2-1).
Group. Such a component (B) is a tetracarboxylic acid
Dianhydride and a diamine represented by the following formula (23):
Polyamic acid using diamine containing at least mol%
Can be obtained by synthesis and dehydration ring closure.

[0032]

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In the formula, R ⁵ and X are defined by the formula (2-1)
Same as

The diamine represented by the above formula (23) is an alkyl group having 10 to 20 carbon atoms or a C4 to C4
It is a diamine having at least one selected from 0 alicyclic skeletons. Examples of the alkyl group having 10 to 20 carbon atoms include an n-decyl group, an n-dodecyl group, an n-hexadecyl group, an n-octadecyl group, and an n-eicosyl group. Further, as the alicyclic skeleton having 4 to 40 carbon atoms,
Alicyclic skeletons derived from cycloalkanes such as cyclobutane, cyclopentane, cyclohexane and cyclodecane; steroid skeletons such as cholesteryl group and cholesteryl group; norbornene skeleton and adamantane skeleton.
Among these, an alicyclic skeleton having 4 to 40 carbon atoms is preferable, and a steroid skeleton is particularly preferable.

Further, these alkyl groups or alicyclic skeletons may be partially or entirely substituted by halogen atoms. As the divalent organic group represented by X, -O-, -COO-,-
OCO -, - NHCO -, - CONH -, - CO- and -CH ² O-, methylene group, such as an alkylene group, and as particularly preferred, -O -, - COO- and -OCO- are mentioned .

Specific examples of the diamine having such a structure include compounds represented by the following formulas (24) to (29), n-decyloxy-2,4-diaminobenzene, n
-Dodecyloxy-2,4-diaminobenzene, n-hexadecyloxy-2,4-diaminobenzene, n-octadecyloxy-2,4-diaminobenzene, 2-n
-Decyloxy-1,4-diaminobenzene, 2-n-
Dodecyloxy-1,4-diaminobenzene, 2-n-
Hexadecyloxy-1,4-diaminobenzene, 2-
n-octadecyloxy-1,4-diaminobenzene,
n-decanoxymethyl-2,4-diaminobenzene, n
-Dodecanoxymethyl-2,4-diaminobenzene, n
-Hexadecanoxymethyl-2,4-diaminobenzene, n-octadecanoxymethyl-2,4-diaminobenzene, 2-n-decanoxymethyl-1,4-diaminobenzene, 2-n-dodecanoxymethyl -1,4-diaminobenzene, 2-n-hexadecanoxymethyl-1,
Examples thereof include 4-diaminobenzene, 2-n-octadecanoxymethyl-1,4-diaminobenzene, and the like. Among them, the compounds represented by the following formulas (24) to (29) are preferable because the printability of the obtained liquid crystal aligning agent is further improved, and particularly preferable is the following formula (2)
4) Compounds represented by (27).

[0037]

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In the synthesis of the component (B), the above formula (2)
The amount of the diamine represented by 3) is at least 10 mol%, preferably at least 15 mol%, more preferably at least 20 mol% of the total diamine used in the synthesis of the component (B). The diamine represented by the above formula (23) may be used in combination with the component (A). <Synthesis of polyamic acid> The ratio of the tetracarboxylic dianhydride and the diamine used in the synthesis reaction of the polyamic acid is such that the acid anhydride group of the tetracarboxylic dianhydride is equivalent to 1 equivalent of the amino group of the diamine. The ratio is preferably 0.2 to 2 equivalents, more preferably 0.3 to 1.2 equivalents.

The synthesis reaction of the polyamic acid is carried out in an organic solvent at a temperature of preferably -20 to 150 ° C, more preferably 0 to 100 ° C. Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized polyamic acid. For example, N-methyl-2
-Pyrrolidone, N, N-dimethylacetamide, N, N-
Non-protic polar solvents such as dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea and hexamethylphosphortriamide; phenolic solvents such as m-cresol, xylenol, phenol and halogenated phenol can be exemplified. The amount (α) of the organic solvent used is usually such that the total amount (β) of tetracarboxylic dianhydride and diamine is 0.1 to 30% by weight based on the total amount (α + β) of the reaction solution. It is preferable that the amount is large.

The organic solvent includes alcohols, ketones, esters, and the like, which are poor solvents for polyamic acid.
Ethers, halogenated hydrocarbons, hydrocarbons and the like can be used in combination as long as the generated polyamic acid does not precipitate. Specific examples of such poor solvents 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, o-
Examples thereof include dichlorobenzene, hexane, heptane, octane, benzene, toluene, and xylene.

As described above, a reaction solution obtained by dissolving the polyamic acid is obtained. 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. The polyamic acid can be purified by dissolving the polyamic acid in an organic solvent again and then performing a step of precipitating with a poor solvent once or several times.

<Imidated Polymer> The imidized polymer constituting the liquid crystal aligning agent of the present invention can be synthesized by at least partially dehydrating and cyclizing a polyamic acid. The dehydration and ring closure of the polyamic acid can be performed by (i) heating the polyamic acid or (ii) dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst to the solution, and heating as necessary. Done by the method. The imidized polymer used in the present invention has a partially dehydrated and ring-closed imidization ratio (the ratio of the imide ring repeating unit to the total number of amic acid repeating units and imide ring repeating units in the polymer is as follows: % (Expressed in%)) may be contained.

The imidization ratio of the imidized polymer in the present invention can be determined as follows. After the polymer was dried under reduced pressure at room temperature, dissolved in deuterated dimethyl sulfoxide at room temperature by ¹ H tetramethylsilane as reference substance
-NMR is measured and determined by the formula shown by the following formula (ii). Imidation ratio (%) = (1-A ¹ / A ² × α) × 100 (ii) A ¹ : peak area derived from proton of NH group (10 pp)
m) A ² : peak area derived from other protons α: N in a polymer precursor (polyamic acid)
The ratio of the number of other protons to one proton of the H group The imidation ratio can be adjusted by the amount of the dehydrating agent or dehydrating ring-closing agent used. The component (B) used in the present invention needs to have an imidization ratio of 40% or more, preferably 50% or more, and more preferably 70% or more. If it is less than 40%, sufficient vertical orientation and low residual D
C cannot be obtained. The component (A) used in the present invention preferably has an imidization ratio of 20% or less.

The reaction temperature in the method (i) for heating a polyamic acid is preferably 50 to 200 ° C., more preferably 60 to 170 ° C. When the reaction temperature is lower than 50 ° C., the dehydration ring-closing reaction does not sufficiently proceed, and when the reaction temperature exceeds 200 ° C., the molecular weight of the obtained imidized polymer may decrease. On the other hand, in the above method (ii) of adding a dehydrating agent and a dehydration ring-closing catalyst to a solution of a polyamic acid, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride is used as the dehydrating agent. Can be. The amount of the dehydrating agent used depends on the desired imidization ratio, but usually, the repeating unit 1 of the polyamic acid is used.
It is preferably 0.01 to 20 mol per mol.
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 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.

As the organic solvent used for the dehydration ring closure reaction, the same organic solvents as those exemplified for the synthesis of the polyamic acid can be used. Also,
The reaction temperature of the dehydration ring closure reaction is generally 0 to 180 ° C, preferably 10 to 150 ° C. The imidized polymer can be purified by subjecting the reaction solution thus obtained to the same operation as the method for purifying the polyamic acid.

<Terminal-Modified Polymer> The polyamic acid and imidized polymer used in the present invention may be of a terminal-modified type 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, when synthesizing a polyamic acid, an acid monoanhydride, a monoamine compound,
It can be synthesized by adding a monoisocyanate compound or the like to the reaction system. 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 aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, and 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.

The polyamic acid and imidized polymer obtained as described above have a logarithmic viscosity (η _ln ) value of preferably 0.05 to 10 dl / g, more preferably 0.05 to 5 dl / g. is there. 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 and obtaining the following formula (i )
Is required by

[0048]

(Equation 1)

The ratio of the component (A) to the component (B) is such that the component (B) is 1 to 99% by weight, preferably 5 to 95% by weight. If the amount of the component (B) is 1% by weight or less, sufficient vertical orientation cannot be obtained, and if it is 99% by weight or more, sufficient adhesion and printability cannot be obtained. <Liquid crystal aligning agent> The liquid crystal aligning agent of the present invention is generally constituted by dissolving and containing the components (A) and (B) in an organic solvent.

The temperature for preparing the liquid crystal aligning agent of the present invention is usually from 0 ° C. to 200 ° C., preferably from 20 ° C. to 60 ° C.
It is. Examples of the organic solvent constituting the liquid crystal alignment agent of the present invention include the solvents exemplified as those used in the synthesis reaction of the polyamic acid. In addition, the poor solvents exemplified as those which can be used together in the synthesis reaction of the polyamic acid can be appropriately selected and used in combination.

The solid content in the liquid crystal aligning agent of the present invention is selected in consideration of viscosity, volatility and the like, but 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 alignment film. When the solid content concentration is less than 1% by weight, the thickness of the coating film is reduced. When the solid content concentration exceeds 10% by weight, the thickness of the coating film becomes excessively large and a good liquid crystal alignment film cannot be obtained. In addition, the viscosity of the liquid crystal aligning agent is increased, and the coating characteristics are inferior.

The liquid crystal aligning agent of the present invention may contain a functional silane-containing compound or an epoxy compound from the viewpoint of improving the adhesion to the substrate surface as long as the desired physical properties are not impaired. Examples of such functional silane-containing compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl) -3-
Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxy Silane, 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. Such epoxy group-containing compounds include, for example, 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,
5,6-tetraglycidyl-2,4-hexanediol,
N, N, N ', N',-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ', N',-tetraglycidyl- 4,4'-diaminodiphenylmethane, 3- (N
-Allyl-N-glycidyl) aminopropyltrimethoxysilane and 3- (N, N-diglycidyl) aminopropyltrimethoxysilane.

[0053]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. [Polymer imidation ratio] After drying the polymer under reduced pressure at room temperature, it was dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance. It was determined by the formula shown. Imidation ratio (%) = (1-A ¹ / A ² × α) × 100 (ii) A ¹ : peak area derived from proton of NH group (10 pp)
m) A ² : peak area derived from other protons α: N in a polymer precursor (polyamic acid)
One proton of H group

[Printability] Printing was performed using Nissha Angstrom, and the substrate after post-baking was observed with a microscope. No printing unevenness ○ Printing unevenness × [Pretilt angle] 2% by OMS-J3 manufactured by Chuo Seiki
From the deviation of the retardation from the symmetry angle at 5 ° C,
The pretilt angle was calculated. [Voltage holding ratio of liquid crystal display element] A voltage of 5 V was applied to the liquid crystal display element for an application time of 60 microseconds for a span of 167 milliseconds, and then a voltage holding ratio 167 milliseconds after the application was canceled was measured. The measuring device is VHR manufactured by Toyo Corp.
-1 was used. [Residual DC voltage] A 30 Hz, 2.0 V rectangular wave obtained by superimposing a DC voltage of 1.0 V on the liquid crystal display element was applied at a temperature of 70 ° C. for 1 hour.
Immediately after the DC voltage was cut off, the voltage remaining in the liquid crystal cell was measured by a flicker-elimination method to obtain a residual DC voltage.

Synthesis Example 1 (Synthesis of Component (A)) Diamine and tetracarboxylic dianhydride were added to 450 g of 1-methyl-2-pyrrolidone so that the monomer concentration shown in Table 1 was 20% by weight. Were added in this order and reacted at room temperature for 4 hours to obtain a polyamic acid.

Synthesis Examples 2 to 7 and Comparative Synthesis Examples 1 and 2 ((B)
Synthesis of Components) Diamine and tetracarboxylic dianhydride were added to 450 g of 1-methyl-2-pyrrolidone in this order so that the solid content concentration was 20% by weight by charging the monomers shown in Table 1, and then 60 ° C. For 4 hours to obtain a polyamic acid. Subsequently, 1-methyl-2-pyrrolidone was added to adjust the solid content concentration to 5% by weight.
The dehydration ring closure reaction was performed at 0 ° C. for 4 hours. Next, this reaction solution was poured into diethyl ether, and the precipitate was recovered and dried to obtain an imidized polymer.

[0057]

[Table 1]

Examples 1 to 4 and Comparative Example 1 The polyamic acid (A) obtained in Synthesis Example 1 was added to N, N, N ',
N ',-tetraglycidyl-4,4'-diaminodiphenylmethane was converted to the total polymer amount (component (A) + component (B)) 1
1 part by weight of 1-methyl-2-pyrrolidone / 4-hydroxy-4-methyl-
A mixed solvent of 2-pentanone (60/40 by weight) and the imidized polymer (B) obtained in Synthesis Examples 2 to 7 were blended as shown in Table 2 to give a solid content of 6% by weight. After adjustment as described above, the mixture was filtered through a 1-micron filter to obtain a liquid crystal aligning agent. Using the obtained liquid crystal aligning agent, a liquid crystal display device was obtained by the following method.

Fabrication of a liquid crystal display element: A liquid crystal aligning agent is applied on a transparent conductive film made of an ITO film provided on one surface of a glass substrate having a thickness of 1 mm by using a spinner, and is applied at 80 ° C. for 1 minute, and then 180 ° By heating and drying at a temperature of 1 ° C. for 1 hour, a coating film having a dry film thickness of 600 Å was formed.
Next, by performing a rubbing process using a rubbing machine having a roll wound with rayon cloth,
Liquid crystal alignment ability was imparted to the coating film to form a liquid crystal alignment film. Here, the rubbing treatment conditions are as follows:
m, the stage moving speed was 30 mm / sec, and the length of the pressed foot was 0.4 mm. Two substrates on which the liquid crystal alignment film was formed as described above were prepared, and the outer edge of each substrate was
After applying an epoxy resin-based adhesive containing aluminum oxide spheres by a screen printing method, the two substrates were arranged to face each other with a gap therebetween, and the outer edges were brought into contact with each other and pressed to cure the adhesive. . A negative nematic liquid crystal was injected and filled into the cell gap defined by the adhesive on the surface of the substrate and the outer edge, and then the injection hole was sealed with an epoxy adhesive to produce a liquid crystal display device. Table 2 shows the evaluation results of these liquid crystal alignment agents and liquid crystal display elements.

[0060]

[Table 2]

[0061]

According to the present invention, when a liquid crystal alignment film is formed, a liquid crystal alignment film having good liquid crystal vertical alignment, high voltage holding characteristics, low residual DC, and excellent printability can be formed. The liquid crystal aligning agent which can be provided can be provided.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Keiichi Yamamoto 2-11-10 Tsukiji 2-chome, Chuo-ku, Tokyo JSR Corporation F-term (reference) 2H090 HB08Y KA05 MA10 MB01 4J002 CM04W CM04X GP00 4J043 QB31 RA34 SA31 SA52 SA54 SA61 SA63 TA70 TA79 UA012 UA032 UA042 UA061 UA062 UA081 UA082 UA111 UA112 UA122 UA132 UA231 UA261 UA262 UA361 UA391 UA591 UB012 UB122 UB211 UB281 UB282 UB301 UB302 UB311 Z51Z51A51

Claims (2)

[Claims] (A) The following formula (1):Where R¹Is a tetravalent organic radical and R^TwoIs divalent
A polyamic acid having a repeating unit represented by
Imi obtained by partially dehydrating and ring closing the polyamic acid.
At least one kind of weight selected from the group consisting of
And (B) the following formula (2):Where R^ThreeIs a tetravalent organic radical and R^FourIs divalent
A base, provided that R ^FourAt least 10 mol%
Is a divalent organic group represented by the following formula (2-1)
AndWhere R^FiveIs an alkyl group having 10 to 20 carbon atoms or carbon
A monovalent organic group having an alicyclic skeleton having a prime number of 4 to 40;
X is a divalent organic group, and the polyamic acid having a repeating unit represented by
The imidation ratio obtained by partially dehydrating and ring-closing is 40%
Liquid crystal alignment comprising the above imidized polymer
Agent. 2. The liquid crystal aligning agent according to claim 1, wherein at least 50 mol% of R ^{1 in} the formula (1) is a tetravalent alicyclic group.