JP2002327058A - Vertical-orientation type liquid crystal orientation agent and liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical-orientation type liquid crystal orientation agent, excellent in vertical orientation, short in erasing time of persistent vision in a liquid crystal display element, and preferably usable as a MVA-type liquid crystal display element, and to provide a liquid crystal display element. SOLUTION: The vertical-orientation type liquid-crystal orientation agent is composed of a polymer having a diamine of a specific structure, and a repeating unit having an imide ring, wherein repeating unit is 40 mol% or above of a total repeating unit, and the liquid crystal display element using the same is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vertical alignment type liquid crystal aligning agent. More specifically, vertical alignment, printability, the afterimage erasing time of a liquid crystal display element are short, and MVA (Multi
-Domain Vertical Alignment
The present invention relates to a vertical alignment type liquid crystal aligning agent particularly suitable for a liquid crystal display device of the t) type.

[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 (Twisted Nemati)
A TN type liquid crystal display device having a c) type 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 devices and vertical alignment type liquid crystal display devices have been developed. This S
The TN 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 the liquid crystal molecule is continuously twisted over 180 degrees between the substrates. This utilizes the birefringence effect that occurs. On the other hand, "liquid crystal" Vo
l. 3 No. 2117 (1999) and JP-A-11-258605.
MVA that controls the alignment direction of liquid crystal by forming protrusions on top
A vertical alignment type liquid crystal display device called a system has been proposed. The MVA-type liquid crystal display element is excellent in the manufacturing process, such as being excellent in viewing angle, contrast and the like, and not requiring rubbing treatment in forming a liquid crystal alignment film.
A liquid crystal alignment film suitable for the MVA method is required to have such properties as excellent vertical alignment and a short afterimage erasing time of a liquid crystal display device.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal display device having an excellent vertical alignment property and a short afterimage erasing time.
An object of the present invention is to provide a vertical alignment type liquid crystal alignment agent suitably used for a VA type liquid crystal display element and a liquid crystal display element using the same. Still other objects and advantages of the present invention will become apparent from the following description.

[0004]

According to the present invention, the above objects and advantages of the present invention are attained by providing a repeating unit represented by the following formula (I-1) and a repeating unit represented by the following formula (I-2) A polymer having at least one kind of repeating unit selected from units, and having a repeating unit having an imide ring in an amount of 40 mol% or more of all repeating units (hereinafter, also referred to as “specific polymer”). This is achieved by a vertical alignment type liquid crystal alignment agent.

[0005]

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Wherein P ¹ is a tetravalent organic group and Q ¹
Is a group represented by the following formula (Q-1) or (Q-2). )

[0007]

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Wherein P ² is a tetravalent organic group and Q ²
Is a group represented by the following formula (Q-1) or (Q-2). )

[0009]

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(Wherein X is -O-, -CO-, -COO
-, -OCO-, -NHCO-, -CONH-, -S
-, A methylene group, a divalent group selected from an alkylene group having 2 to 6 carbon atoms and a phenylene group, wherein R ¹ is an alkyl group having 10 to 20 carbon atoms and an alicyclic skeleton having 4 to 40 carbon atoms. A monovalent organic group or a monovalent organic group having a fluorine atom having 6 or more carbon atoms. )

[0011]

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(Wherein X is -O-, -CO-, -COO
-, -OCO-, -NHCO-, -CONH-, -S
—, A methylene group, a divalent group selected from an alkylene group having 2 to 6 carbon atoms and a phenylene group, and R ² is a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms. )

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The vertical alignment type liquid crystal alignment agent of the present invention is constituted by dissolving a specific polymer in an organic solvent. The specific polymer,
It is obtained by dehydrating and ring-closing a part or all of a polyamic acid having 5 mol% or more of the repeating unit represented by the formula (Q-1) in all the repeating units.

[Polyamic acid] <Tetracarboxylic dianhydride> As the tetracarboxylic dianhydride used in the synthesis of the above polyamic acid, an alicyclic tetracarboxylic dianhydride is preferable. Specific examples of the alicyclic tetracarboxylic dianhydride include, for example, 1,
2,3,4-cyclobutanetetracarboxylic 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-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,
3,3a, 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, 3-oxabicyclo [3,2,1] octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione) And the compounds represented by the following formulas (I) and (II).

[0015]

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(Wherein, R ³ and R ⁵ represent a divalent organic group having an aromatic ring, R ⁴ and R ⁶ represent a hydrogen atom or an alkyl group, and a plurality of R ⁴ and R ⁶ are represented by , May be the same or different.)

Other tetracarboxylic dianhydrides include aliphatic tetracarboxylic dianhydrides such as butanetetracarboxylic dianhydride; pyromellitic dianhydride,
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'-dimethyldiphenylsilanetetra Carboxylic 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) diphenylsulfone 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-
Aromatic tetracarboxylic dianhydrides such as bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate) and compounds represented by the following formulas (1) to (4) can be given. These are used alone or in combination of two or more.

[0018]

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Of the above alicyclic tetracarboxylic dianhydrides, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid Dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2, 3,5-tricarboxycyclopentylacetic acid dianhydride, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, cis-3,7-dibutyl Cycloocta-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, 1,3,3a, 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-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,
3-oxabicyclo [3,2,1] octane-2,4-
Dione-6-spiro-3 '-(tetrahydrofuran-
2 ′, 5′-dione), among the compounds represented by the formula (I), the compounds represented by the following formulas (5) to (7) and the compound represented by the following formula (II): The compound represented by (8) is preferable from the viewpoint that good liquid crystal alignment can be exhibited.
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, 3-oxabicyclo [3,2,
1] Octane-2,4-dione-6-spiro-3'-
(Tetrahydrofuran-2 ', 5'-dione) and a compound represented by the following formula (5).

[0020]

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Among other tetracarboxylic dianhydrides, preferred are butanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride. Things, 3,3 ', 4,
4'-biphenylsulfonetetracarboxylic dianhydride,
1,4,5,8-naphthalenetetracarboxylic dianhydride and the like can be mentioned. Of these tetracarboxylic dianhydrides, the content of the alicyclic tetracarboxylic dianhydride is preferably 50 mol% or more based on all the tetracarboxylic dianhydrides.

<Diamine> The groups represented by the above formulas (Q-1) and (Q-2) are groups derived from a diamine for synthesizing a polyamic acid. Hereinafter, the diamine having a group represented by the above formula (Q-1) or the above formula (Q-2) is also referred to as “specific diamine”. In the formula (Q-1), examples of the alkyl group having 10 to 20 carbon atoms represented by R ¹ include an n-decyl group, an n-dodecyl group, and an n-
Examples include a pentadecyl group, an n-hexadecyl group, an n-octadecyl group, and an n-eicosyl group. Examples of the organic group having an alicyclic skeleton having 4 to 40 carbon atoms represented by R ¹ in the above formula (Q-1) and R ² in the above formula (Q-2) include cyclobutane and cyclopentane. Groups having an alicyclic skeleton derived from cycloalkane such as cyclohexane and cyclodecane; groups having a steroid skeleton such as cholesterol and cholestanol; and groups having a bridged alicyclic skeleton such as norbornene and adamantane. Among them, particularly preferably, n
-An octadecyl group, a group having an alicyclic skeleton derived from cyclohexane or a group having a steroid skeleton. The organic group having an alicyclic skeleton may be a group substituted with a halogen atom, preferably a fluorine atom.

Examples of the group having a fluorine atom having 6 or more carbon atoms represented by R ¹ in the above formula (Q-1) include, for example, n-hexyl group, n-octyl group, n-decyl group and the like. A linear alkyl group having 6 or more carbon atoms; an alicyclic hydrocarbon group having 6 or more carbon atoms such as a cyclohexyl group and a cyclooctyl group; an aromatic hydrocarbon group having 6 or more carbon atoms such as a phenyl group and a biphenyl group; Examples include a group in which part or all of the hydrogen atoms in an organic group are substituted with a fluorine atom or a fluoroalkyl group.

The above formula (Q-1) and the above formula (Q
As the divalent organic group represented by X in -2),-
O-, -COO-, -OCO-, -NHCO-, -CO
NH-, -CO-, a methylene group, an alkylene group having 2 to 6 carbon atoms and a phenylene group. Of these, a group represented by -O-, -COO- or -OCO- is particularly preferable.

Specific examples of the diamine having a group represented by the above formula (Q-1) include dodecanoloxy-2,4-diaminobenzene, pentadecanoloxy-2,4-diaminobenzene, and hexadecanoloxy-2,4-diaminobenzene. And octadecanoxy-2,4-diaminobenzene, and compounds represented by the following formulas (9) to (16).

[0026]

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Specific examples of the diamine having a group represented by the above formula (Q-2) include the following formulas (17) to (2)
The diamine represented by 1) can be mentioned as a preferable example.

[0028]

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In synthesizing the polyamic acid used in the present invention, other diamine compounds may be used in combination as long as the effects of the present invention are not impaired. Other diamine compounds include, for example, p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenylsulfide, 4,4′-diamino Diphenylsulfone, 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide,
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-aminophenyl) hexafluoropropane, , 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-trifluoromethylphenoxy) ) Phenyl] hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluoro Aromatic diamines such as biphenyl;

1,1-methaxylylenediamine, 1,3-
Propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine,
1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine,
Aliphatic and cycloaliphatic 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- Two primary amino groups and one such primary amino group in a molecule such as diamino-6-phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine A diamine having a nitrogen atom other than the following;
And diaminoorganosiloxane represented by I).

[0032]

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(Wherein, R ⁷ represents a hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ⁷ 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. )

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

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 Ridene) bisaniline, 1,4-cyclohexanediamine, 4,4′-methylenebis (cyclohexylamine), 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2 , 6-Diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine and the like are preferred.

The proportion of the specific diamine in the total diamine component in the total polymer contained in the liquid crystal aligning agent of the present invention is preferably 5 mol% or more, more preferably 10 mol%, based on the total amount of the diamine component. That is all. If the use ratio is less than 5 mol%, a sufficient effect on the vertical alignment may not be obtained.

<Synthesis of Polyamic Acid> The ratio of tetracarboxylic dianhydride and diamine used in the synthesis reaction of polyamic acid is such that the acid anhydride of tetracarboxylic dianhydride is equivalent to 1 equivalent of amino group of diamine. The substance group is 0.2 to
A ratio of 2 equivalents is preferred, more preferably 0.3 equivalent.
It is a ratio of ~ 1.2 equivalents. The synthesis reaction of polyamic acid is usually carried out in an organic solvent at -20 ° C to 150 ° C.
C., preferably at a temperature of 0 to 100C.

Here, the organic solvent is not particularly limited as long as it can dissolve the polyamic acid to be synthesized. For example, 1-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide Dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide and the like; aprotic polar solvents; m-cresol, xylenol, phenol, halogenated phenol and the like. 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 above organic solvents include alcohols, ketones, esters 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.

<Dehydration Ring Closure Reaction> The specific polymer constituting the liquid crystal aligning agent of the present invention can be synthesized by dehydration ring closure of a part or all of the above polyamic acid.
In the specific polymer used in the present invention, the proportion of the repeating unit having an imide ring in all the repeating units (hereinafter, also referred to as “imidization ratio”) is at least 40 mol%, preferably 5%.
0 mol% or more. By using a polymer having an imidation ratio of 40 mol% or more, a liquid crystal alignment agent capable of forming a liquid crystal alignment film having a short afterimage erasing time can be obtained.

The dehydration and ring closure of the polyamic acid can be carried out by (i) heating the polyamic acid or (ii) dissolving the polyamic acid in an organic solvent and adding a dehydrating agent and a dehydration ring-closing catalyst to this solution, if necessary. This is performed by a method of heating. The reaction temperature in the method (i) for heating a polyamic acid is preferably from 50 to 200C, more preferably from 60 to 170C. 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 imidation ratio, but is preferably 0.01 to 20 mol per 1 mol of the repeating unit of the polyamic acid. 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. The imidation ratio can be increased as the amount of the above-mentioned dehydrating agent and dehydrating ring-closing agent increases. In addition, as the organic solvent used for the dehydration ring closure reaction, the organic solvents exemplified as those used for the synthesis of polyamic acid can be exemplified. The reaction temperature of the dehydration ring closure reaction is preferably 0.
-180 ° C, more preferably 10-150 ° C. The specific polymer obtained can be purified by subjecting the reaction solution thus obtained to the same operation as in the method for purifying a polyamic acid.

<Terminal-Modified Polymer> The specific polymer used in the present invention may be a terminal-modified polymer 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 polymer 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. Here, as the acid monoanhydride, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic 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-tetradecylamine,
n-pentadecylamine, n-hexadecylamine, n
-Heptadecylamine, n-octadecylamine, n-
Eicosylamine and the like can be mentioned. In addition, examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

<Logarithmic Viscosity of Polymer> The polyamic acid obtained as described above preferably has a logarithmic viscosity (η _ln ) value of 0.05 to 10 dl / g, more preferably 0.1 to 10 dl / g.
05 to 5 dl / g. In the present invention, the logarithmic viscosity (η
The value of _ln) uses a N- methyl-2-pyrrolidone as a solvent, the concentration was measured viscosity at 30 ° C. for the solution is 0.5 g / 100 ml are those obtained by the following formula (i) .

[0045]

[Liquid Crystal Alignment Agent] The liquid crystal alignment agent of the present invention is usually constituted by dissolving and containing the above specific polymer in an organic solvent. The temperature at the time of preparing the liquid crystal alignment agent of the present invention,
It is preferably 0 ° C to 200 ° C, more preferably 20 ° C to 200 ° C.
C. to 60C.

Examples of the organic solvent constituting the liquid crystal aligning agent of the present invention include 1-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, -Hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate,
Methylmethoxypropionate, ethylethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n
-Propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl Examples thereof include ether acetate and diethylene glycol monoethyl ether acetate.

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 a functional silane-containing compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, 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 Silane and the like can be mentioned. Examples of such epoxy compounds 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, 1,3,5,6
-Tetraglycidyl-2,4-hexanediol, N,
N, N ', N',-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ', N',-tetraglycidyl-4, 4'-diaminodiphenylmethane, 3- (N
-Allyl-N-glycidyl) aminopropyltrimethoxysilane, 3- (N, N-diglycidyl) aminopropyltrimethoxysilane, and the like.

<Liquid crystal display element> The liquid crystal aligning agent of the present invention is M
It can be suitably used for a VA liquid crystal display element.
What is the MVA mode? "Liquid crystal Vol.3 No.2 11
7 (1999) "and Japanese Patent Application Laid-Open No. 11-258605 show a vertical alignment mode using projections as alignment control means. The projections may be formed on the TFT substrate side and the color filter side, respectively. It is also possible to have a projection on the color filter side and a slit on the TFT side.

The liquid crystal display device obtained by using the liquid crystal aligning agent of the present invention can be manufactured, for example, by the following method. (1) The liquid crystal aligning agent of the present invention is applied, for example, by a roll coater method, a spinner method, or a printing method on one surface of a substrate on which a patterned transparent conductive film is provided or on a transparent conductive film on which projections are formed as alignment regulating means. And then heating the coated surface to form a coating. Here, as the substrate, for example, float glass,
A transparent substrate made of glass such as soda glass; plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, and polycarbonate can be used. Further, as a transparent conductive film provided on one surface of the substrate, a NESA film (registered trademark of US PPG) made of tin oxide (SnO ₂ ) and an ITO made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ )
A film or the like can be used, and a photo-etching method or a method using a mask in advance is used for patterning these transparent conductive films. In addition, the layout of the projections, such as forming a projection on the substrate to define the alignment direction of the liquid crystal and slits in the electrodes, and the design of the electrode structure and the way of applying an electric field, reduce the viewing angle dependence. An improved liquid crystal display device can be obtained. In applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate surface and the transparent conductive film and the liquid crystal aligning agent film, a functional silane-containing compound, a functional titanium-containing compound, etc. Can be applied in advance. The heating temperature is 80 to 250 ° C, preferably 120 to 200 ° C.
It is said. The thickness of the formed film is usually 0.001 to
It is 1 μm, preferably 0.005 to 0.5 μm. In addition, the liquid crystal alignment agent of the present invention forms a film to be a liquid crystal alignment film by removing the organic solvent after coating, and further heats to promote dehydration ring closure,
A partially or completely imidized film may be used.

(2) Two substrates on each of which a liquid crystal alignment film is formed as described above are prepared, arranged to face each other with a gap (cell gap) therebetween, and the peripheral portions of the two substrates are bonded with a sealant. Liquid crystal is injected and filled into the substrate surface and the cell gap defined by the sealant, and the injection hole is sealed to form a liquid crystal cell. Then, by attaching a polarizing plate to the outer surface of the liquid crystal cell, that is, the other surface of each substrate constituting the liquid crystal cell, a liquid crystal display element is obtained.

Here, as the sealing agent, 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,
Biphenyl-based liquid crystal, phenylcyclohexane-based liquid crystal, ester-based liquid crystal, terphenyl-based liquid crystal, biphenylcyclohexane-based liquid crystal, pyrimidine-based liquid crystal, dioxane-based liquid crystal, bicyclooctane-based liquid crystal, cubane-based liquid crystal, and 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. Further, p-decyloxybenzylidene-p
Ferroelectric liquid crystals such as -amino-2-methylbutylcinnamate can also be used. Further, as a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing plate or an H film in which a polarizing film called an H film absorbing iodine is sandwiched by a cellulose acetate protective film while stretching and aligning polyvinyl alcohol. A polarizing plate composed of itself can be mentioned.

[0054]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. [Method of measuring imidation ratio of specific polymer] After drying the polymer under reduced pressure at room temperature, it is dissolved in deuterated dimethyl sulfoxide, and 1H-
NMR was measured and determined by the formula shown in the following formula (ii).

Amount of imidization (%) = (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)
Number ratio of other protons to one proton of H group

[Production Method of Liquid Crystal Display Element] Production of Liquid Crystal Display Element: As shown in FIG. 1, a glass substrate with an ITO (A) having projections formed using a positive resist and a glass substrate having an ITO pattern Each of the liquid crystal aligning agents was printed on (B) and dried at 80 ° C. for 1 minute and then at 180 ° C. for 1 hour to form a coating film having a dry film thickness of 600 Å. Two substrates on which a liquid crystal alignment film was formed as described above were prepared, and an epoxy resin-based adhesive containing aluminum oxide spheres having a particle size of 3.5 μm was screen-printed on the outer edge of the substrate (B) by a screen printing method. After the application, the two substrates were bonded so as to have a positional relationship as shown in FIG. The cell gap defined by the adhesive on the surface and the outer edge of the substrate is filled with a negative liquid crystal MLC6608 manufactured by Merck Co., Ltd., and the injection hole is sealed with an epoxy-based adhesive to form a vertical alignment type liquid crystal display device. Was prepared.

[Vertical Orientation] When voltage is OFF and AC 1
The liquid crystal display device at 2 V (peak-peak) was observed under crossed Nicols. [Voltage holding ratio] After applying a voltage of 5 V to the liquid crystal display element for an application time of 60 microseconds and a span of 167 milliseconds,
The voltage holding ratio was measured 167 ms after the application was released.
The measuring device used was VHR-1 manufactured by Toyo Corporation.

[Afterimage erasing time of liquid crystal display element] DC 3.0 V, AC 6.0 V (peak-peak) is applied to the liquid crystal display element.
Was applied for 20 hours at an environmental temperature of 70 ° C., the voltage was turned off, and the time until the afterimage was erased was visually observed.

<Synthesis of Specific Polymer> Synthesis Examples 1 to 7 Diamine and tetracarboxylic dianhydride were added to 1-methyl-2-pyrrolidone in the order shown in Table 1 in the order of diamine and tetracarboxylic dianhydride to obtain a solid content of 20%. The mixture was reacted at 60 ° C. for 6 hours to obtain a polyamic acid having an logarithmic viscosity shown in Table 1.

[0060]

[Table 1] Figures in parentheses are mol% TCAAH: 2,3,5-tricarboxycyclopentylacetic dianhydride CB: 1,2,3,4-cyclobutanetetracarboxylic anhydride MTDA: 1,3,3a, 4,5, 9b-Hexahydro-5
-8-methyl- (tetrahydro-2,5-dioxo-3
-Furanyl) -naphtho [1,2-C] furan-1,3-dione PDA: p-phenylenediamine ODA: octadecanoxy-2,4-diaminobenzene diamine: diamine represented by the formula (9) diamine: formula ( Diamine represented by 10) Diamine: Diamine represented by formula (13)

Synthesis Examples 8 to 17 The polyamic acid obtained in Synthesis Examples 1 to 7 was 1-methyl-
After diluting to a solid concentration of 5% with 2-pyrrolidone, pyridine and acetic anhydride were added as catalysts shown in Table 2, and 11%
By stirring at 0 ° C. for 4 hours, a specific polymer was synthesized.
The polymer solution was reprecipitated with diethyl ether to obtain a white powder of a polymer (imidized polymer).
Table 2 also shows the imidation ratio of the obtained specific polymer.
In Table 2, pyridine / acid anhydride (fold molar) = 1.0 /
1.0 means that 1.0 mol of pyridine and 1.0 mol of acetic anhydride are added to 1.0 mol of amide bonds in the polyamic acid.

[0062]

[Table 2]

Synthesis Examples 18 to 27 Diamine and tetracarboxylic dianhydride were added to 1-methyl-2-pyrrolidone in the order shown in Table 3 in the order shown, and the mixture was reacted at 60 ° C. for 6 hours at a solid content of 20%. Thus, a polyamic acid having a logarithmic viscosity shown in Table 3 was obtained.

[0064]

[Table 3] Numbers in parentheses are mol% TDA: 1,3,3a, 4,5,9b-hexahydro-5-
(Tetrahydro-2,5-dioxo-3-furanyl)-
Naphtho [1,2-C] furan-1,3-dione MTDA: 1,3,3a, 4,5,9b-hexahydro-5
-Methyl-5 (tetrahydro-2,5-dioxo-3-
Furanyl) -naphtho [1,2-c] -furan-1,3-dione TNA: 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride CHA: Formula ( Acid anhydride represented by 1) DDE: 4,4'-diaminodiphenyl ether diamine: diamine represented by formula (10) Diamine: diamine represented by formula (21) Diamine: represented by formula (17) Diamine Diamine: Diamine represented by the formula (16)

Synthesis Examples 28 to 39 The obtained polyamic acid was diluted with 1-methyl-2-pyrrolidone to a solid concentration of 5%, pyridine and acetic anhydride were added as catalysts shown in Table 4, and the mixture was heated at 110 ° C. for 4 hours. By stirring, a specific polymer was synthesized. The polymer solution was reprecipitated with diethyl ether to obtain a white powder of a polymer (imidized polymer). Table 4 also shows the imidation ratio of the obtained specific polymer. In Table 4, pyridine / acid anhydride (times mol) = 1.0 / 1.0 means that 1.0 mol of pyridine and 1.0 mol of acetic anhydride are used for 1.0 mol of amide bond in polyamic acid. Is added.

[0066]

[Table 4]

Examples 1 to 10 and Comparative Example 1 The specific polymers obtained in Synthesis Examples 8 to 17 were prepared to a solid content of 6.0% with a solvent composition (weight ratio) as shown in Table 5, and the present invention was carried out. Was obtained. Using this liquid crystal aligning agent, a liquid crystal display device was manufactured and various evaluations were made. Table 5 shows the results.

[0068]

[Table 5] NMP: N-methyl-2-pyrrolidone BC: Butyl cellosolve

Examples 11 to 26, Comparative Example 2 Example 11: 95 g of a specific polymer (Synthesis Example 29) and an additive (N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane) Less than
5 g of EP (abbreviated as EP) was dissolved in a solvent (NMP: BC = 5: 5 by weight), and the solid content was adjusted to 6.0% to obtain a vertical alignment type liquid crystal aligning agent of the present invention. Using this liquid crystal aligning agent, the above-mentioned MVA type liquid crystal display element was produced, and various evaluations were made. Table 6 shows the results. In the same manner as in Example 11, specific polymers, additives and solvents were mixed at the ratios shown in Table 6 to adjust the orientation agent, and the characteristics of each were evaluated. The results are all shown in Table 6.

[0070]

[Table 6] Silane: N-glycidyl-N, N-bis [3- (methyldimethylmethoxysilyl) phenyl] amine

[0071]

According to the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal alignment film and a liquid crystal display element having good vertical alignment properties and a short afterimage erasing time and suitable for an MVA type liquid crystal display element.
Furthermore, a liquid crystal display device having a liquid crystal alignment film formed using the liquid crystal alignment agent of the present invention can be effectively used for various devices, for example, a monitor for a direct-view personal computer, a liquid crystal television, and the like, and a projection type. Used for transmissive and reflective display devices.

[Brief description of the drawings]

FIG. 1 is a schematic view of an MVA type liquid crystal cell used in an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 color filter side electrode (ITO) 2 liquid crystal alignment film 3 pixel electrode (ITO) 4 alignment control means (projection) 5 alignment control means (slit) 6 liquid crystal molecules

Continued on the front page F term (reference) 2H090 HB08Y HB13Y HB15Y KA05 KA08 4J043 PA02 QB33 RA05 RA34 RA35 SA06 SA44 SA46 SA47 SA54 SA63 SA85 SB01 TA22 TA32 TA68 TA70 TA71 TA72 TB01 UA031 UA032 UA041 UA042 UA121 UA042 UB162 XA16 XA19 ZA09 ZB23

Claims (2)

[Claims] 1. A repeating unit having at least one kind of repeating unit selected from a repeating unit represented by the following formula (I-1) and a repeating unit represented by the following formula (I-2), and having an imide ring. Is 40 mol% in all repeating units
A vertical alignment type liquid crystal aligning agent, characterized by containing the polymer having the above. Embedded image (Wherein P ¹ is a tetravalent organic group, and Q ¹ is represented by the following formula (Q
-1) or a group represented by (Q-2). ) (Wherein P ² is a tetravalent organic group, and Q ² is represented by the following formula (Q
-1) or a group represented by (Q-2). ) (Wherein X is -O-, -CO-, -COO-, -OCO
—, —NHCO—, —CONH—, —S—, a methylene group, a divalent group selected from an alkylene group having 2 to 6 carbon atoms and a phenylene group, and R ¹ has 10 to 20 carbon atoms.
Having an alicyclic skeleton having 4 to 40 carbon atoms
Having a divalent organic group or a fluorine atom having 6 or more carbon atoms
Is a valence organic group. ) (Wherein X is -O-, -CO-, -COO-, -OCO
—, —NHCO—, —CONH—, —S—, a methylene group, a divalent group selected from an alkylene group having 2 to 6 carbon atoms and a phenylene group, and R ² is an alicyclic ring having 4 to 40 carbon atoms. It is a divalent organic group having a formula skeleton. ) 2. A liquid crystal display device comprising a liquid crystal alignment film obtained by using the vertical alignment type liquid crystal alignment agent according to claim 1.