TWI432852B - Liquid crystal orientation agent and liquid crystal display device - Google Patents

Description

Liquid crystal alignment agent and liquid crystal display element

The present invention relates to a liquid crystal alignment agent and a liquid crystal display element. More specifically, it relates to a liquid crystal alignment agent which is excellent in electrical characteristics and excellent in printability, and a liquid crystal alignment agent for a horizontal electric field type liquid crystal display element obtained therefrom.

A TN type liquid crystal display element having a TN (twisted nematic) type liquid crystal cell has been known, and has a positive dielectric orientation between two substrates which form a liquid crystal alignment film on a surface through a transparent conductive film. The opposite nematic liquid crystal layer constitutes a cell having a sandwich structure, and the long axis of the liquid crystal molecules is continuously twisted by 90 degrees from one substrate to the other substrate.

Further, there is also an STN (Super Twisted Nematic) type liquid crystal display element in which a long axis of the liquid crystal molecules is brought into a state of being continuously twisted by 180 degrees or more between substrates by adding a chiral agent, and the resulting Birefringence effect.

On the other hand, in the horizontal electric field type liquid crystal display device, the two electrodes for driving the liquid crystal are provided in a comb shape on the substrate side, and an electric field parallel to the substrate surface is generated to control the liquid crystal molecules. The biggest feature is that without using an optical compensation film, a wide viewing angle comparable to that of a cathode ray tube without gray-scale inversion and hue change can be obtained. The orientation of the liquid crystal in these liquid crystal display elements is usually manifested by a liquid crystal alignment film subjected to rubbing treatment.

As a material of the liquid crystal alignment film of these liquid crystal display elements, polyimine, polyamine, polyester, etc. are known according to the prior art. In particular, polyimine is used in many liquid crystal display elements because it is excellent in heat resistance, affinity with liquid crystals, mechanical strength, and the like.

Recently, research into improving the display quality and low power consumption, starting with the high precision of liquid crystal display elements, has been increasing, and the range of application of liquid crystal display elements has been expanding. In recent years, in addition to the conventional transmission type, the range of application of liquid crystal display elements such as reflective and semi-transmissive types has also expanded. Further, in order to maintain flatness on the transparent conductive film, an organic film such as a protective film is applied first, and then a liquid crystal alignment film is coated thereon. However, the conventional liquid crystal alignment film made of polyimide and the organic film such as a protective film lacks affinity, and repulsion is likely to occur during coating, and pores are easily generated, which causes alignment of the liquid crystal and the obtained liquid crystal display element. The problem of the decline in electrical characteristics.

An object of the present invention is to provide a liquid crystal alignment film which is obtained from a precursor of polyimine which is useful as a liquid crystal alignment film, polyacrylic acid and polyimine, and has a high voltage holding ratio and is organic to a protective film or the like. The film has good printability, and a transverse electric field type liquid crystal display element having the liquid crystal alignment film is provided.

Other objects and advantages of the invention will be apparent from the description which follows.

According to the present invention, the above objects and advantages of the present invention are attained by a liquid crystal alignment agent characterized by comprising (A) a repeating unit represented by the following formula (I-1) and the following formula (I-2) A polymer of a repeating unit (hereinafter referred to as "specific polymer"), a compound having four epoxy groups in the molecule, and a decane coupling agent.

(wherein P ¹ is a tetravalent organic group and Q ¹ is a divalent organic group).

(In the formula, P ² is a tetravalent organic group different from P ¹ and Q ² is a divalent organic group).

According to the present invention, the above object and advantages of the present invention, and a second object, are achieved by a transverse electric field type liquid crystal display device comprising a liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention.

When the liquid crystal alignment agent of the present invention is applied to an organic film such as a protective film, there is no printing unevenness and pores, and the printability is good, and it is possible to obtain a horizontal electric field type liquid crystal display element which is excellent in voltage holding ratio. Liquid crystal alignment film.

Further, the liquid crystal display element having the alignment film formed by the liquid crystal alignment agent of the present invention is excellent in orientation and reliability of liquid crystal, and can be effectively used for various devices, for example, for desktop computers, watches, clocks, and counting. In display devices such as displays, word processors, personal computers, and liquid crystal televisions.

Hereinafter, the present invention will be described in detail.

The liquid crystal alignment agent of the present invention contains a polymer having a repeating unit represented by the above formula (I-1) and a repeating unit represented by the above formula (I-2). The polymer may be a mixture of (1) a polylysine having a repeating unit represented by the above formula (I-1) and a repeating unit polyimine represented by the above formula (I-2), or may be (2) a polymer in which a repeating unit represented by the above formula (I-1) and a repeating unit represented by the above formula (I-2) are randomly or block-bonded in the same molecule (hereinafter referred to as "partially sulfiminated polymer" ").

The above polylysine can be obtained by ring-opening copolymerization of a tetracarboxylic dianhydride with a diamine compound, which is usually obtained by dehydration ring closure of polyglycine. The partially ruthenium iodide polymer can be generally obtained by a method in which a polyamid acid partial dehydration ring closure or a proline prepolymer is bonded to a quinone imine prepolymer to synthesize a block copolymer.

<polylysine>

[tetracarboxylic dianhydride]

Examples of the tetracarboxylic acid dianhydride include butane tetracarboxylic acid dianhydride, 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, and 1,2-dimethyl-1,2,3. 4-cyclobutane tetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3-dichloro-1,2,3,4 - cyclobutane tetracarboxylic acid dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,2,3,4-cyclopentane Tetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxyl Cyclopentyl acetic acid dianhydride, 3,5,6-tricarboxynorbornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofuran tetracarboxylic dianhydride, 1,3,3a,4,5, 9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione, 1,3,3a,4 ,5,9b-hexahydro-5-ethyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione 1,3,3a,4,5,9b-hexahydro-7-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]- Furan-1,3-diketone, 1,3,3a,4,5,9b-hexahydro-7-ethyl-5-(tetrahydro-2,5-dioxo-3-furan -Naphthalene [1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5 -dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-ethyl-5 -(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-six Hydrogen-5,8-dimethyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione, 5- (2,5-dioxotetrahydrofuranmethylene)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid 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'- An aliphatic or alicyclic tetracarboxylic dianhydride such as a diketone) or a compound represented by the following formulas (I) and (II), (wherein R ¹ and R ³ represent a divalent organic group having an aromatic ring, R ² and R ⁴ represent a hydrogen atom or an alkyl group, and a plurality of R ² and R ^{4 present} may be the same or different); Pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride, 3,3',4,4'-diphenylstilbene tetracarboxylic acid dianhydride, 1,4, 5,8-naphthalenetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic acid dianhydride, 3,3' , 4,4'-dimethyldiphenylnonanetetracarboxylic acid dianhydride, 3,3',4,4'-tetraphenylnonanetetracarboxylic acid dianhydride, 1,2,3,4-furan tetracarboxylic acid Acid dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylanthracene Diacid anhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, 3,3',4,4'-perfluoroisopropylidene diphthalic acid dianhydride , 3,3',4,4'-biphenyltetracarboxylic dianhydride, bis(phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis(triphenylphthalic acid) Anhydride, m-phenylene-bis(triphenylphthalic acid) dianhydride, bis(triphenyl-o-phenylene) Formic acid)-4,4'-diphenyl ether dianhydride, bis(triphenylphthalic acid)-4,4'-diphenylmethane dianhydride, ethylene glycol-di(hydrogen trimellitate) , propylene glycol-di (hydrogen trimellitate), 1,4-butanediol-di (hydrogen trimellitate), 1,6-hexanediol-di(anhydroelellitic acid ester), 1 , 8-octanediol-di(anhydrotrimellitic acid ester), 2,2-bis(4-hydroxyphenyl)propane-di(hydrogen trimellitate), the following formula (1) to (4) An aromatic tetracarboxylic acid dianhydride such as a compound represented by the formula. They can be used alone or in combination of two or more.

Among them, from the viewpoint of exhibiting good liquid crystal alignment, butane tetracarboxylic acid dianhydride, 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3-dimethyl group are preferred. -1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid Anhydride, 2,3,5-tricarboxycyclopentyl acetic acid diacid, 5-(2,5-dioxotetrahydrofuranmethylene)-3-methyl-3-cyclohexene-1,2-di Dicarboxylic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene [1,2-c]-furan -1,3-diketone, 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene [ 1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5,8-dimethyl-5-(tetrahydro-2,5-di Oxo-3-furanyl)-naphthalene [1,2-c]-furan-1,3-dione, bicyclo[2,2,2]-oct-7-ene-2,3,5,6- Tetracarboxylic acid dianhydride, 3-oxabicyclo[3.2.1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), pyromellitic acid Dihydride, 3,3',4,4'- Dibenzophenone tetracarboxylic acid dianhydride, 3,3',4,4'-diphenylstilbene tetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, represented by the above formula (I) Among the compounds represented by the following formulas (5) to (7), and the compound represented by the following formula (8) in the compound represented by the above formula (II). Particularly preferred are 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride. 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro 8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione, 3-oxabicyclo[ 3.2.1] Octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), pyromellitic dianhydride, and a compound represented by the following formula (5) .

The tetravalent organic group represented by P ¹ in the repeating unit (proline acid unit) represented by the above formula (I-1) and the P ² represented by the repeating unit (in the imine unit) represented by the above formula (I-2) The tetravalent organic groups are all groups derived from tetracarboxylic dianhydride. These may be the same or different, and P ¹ in the above formula (I-1) is preferably a group represented by each of the following formulas (i) and (i'). P ^{2 is} preferably a group having an alicyclic skeleton, and particularly preferably a group represented by the following formulas (ii) and (ii').

(wherein R is a halogen atom, a methyl group or an ethyl group, a is an integer of 0 or 1, b is an integer of 0 to 6, c is an integer of 0 to 4, and d is an integer of 0 to 5).

Specific examples of the preferred tetracarboxylic dianhydride in each repeating unit are exemplified, and as the tetracarboxylic dianhydride constituting the guanamine unit, 1,2,3,4-cyclobutanetetracarboxylic acid is exemplified. Anhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid Anhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane IV A carboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, pyromellitic dianhydride, etc. Examples of the tetracarboxylic dianhydride constituting the quinone imine unit include an alicyclic tetracarboxylic dianhydride, particularly 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5. 9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione, 1,3,3a,4 ,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione 1,3,3a,4,5,9b-hexahydro-7-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]- Furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene [1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5,8-dimethyl-5-(tetrahydro-2,5- Dioxo-3-furanyl)-naphthalene [1,2-c]-furan-1,3-dione, etc., more preferably 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1 ,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-di Ketones and 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5 Dioxo-3-furanyl) - naphthalene [1,2-c] - furan-1,3-dione.

[diamine compound]

Examples of the diamine compound used in the synthesis of the polylysine include p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenyl. Ethane, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylanthracene, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4' -diaminobenzamide, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4'-diaminobiphenyl, 5-amino-1 -(4'-aminophenyl)-1,3,3-trimethylindan, 6-amino-1-(4'-aminophenyl)-1,3,3-trimethylindan, 3 , 4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2-di[ 4-(4-Aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4-aminophenyl] Hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]anthracene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminobenzene) Oxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)-10-hydrogen Bismuth, 2,7-diaminopurine, 9,9-bis(4-aminophenyl)purine, 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'-dimethoxyBase-4,4'-diaminobiphenyl,1,4,4'-(p-phenylene isopropylidene)diphenylamine, 4,4,-(m-phenylene isopropylidene) Aniline, 2,2,-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane, 4,4'-diamino-2,2'-di(trifluoro An aromatic diamine such as methyl)biphenyl or 4,4'-bis[(4-amino-2-trifluoromethyl)phenoxy]-octafluorobiphenyl;1,1-m-xylylenediamine; 1,3-propanediamine, butanediamine, pentanediamine, hexamethylenediamine, heptanediamine, octanediamine, decanediamine, 4,4-diaminoheptanediamine, 1,4-diaminocyclohexane Alkane, isophorone diamine, tetrahydrodicyclopentadiene diamine, hexahydro-4,7-methylene dimethylene diamine, tricyclo[6.2.1.0 ^{2 , 7} ]- eleven Aliphatic and alicyclic diamines such as carbene 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)pyridazine, 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-ethoxy acridine lactate, 3,8-diamino-6-phenylphenanthridine, 1,4-diaminopyridazine, 3,6- a diamino acridine, a bis(4-aminophenyl)phenylamine, and a diamine having two primary amino groups in the molecule and a nitrogen atom other than the primary amino group, such as a compound represented by the following formulas (III) to (IV); (Wherein, R ⁵ represents a group selected pyridine, pyrimidine, triazine, piperidine and a monovalent organic group having a nitrogen atom of the piperazine ring structure, X represents 2 monovalent organic group).

(wherein R ⁶ represents a divalent organic group having a cyclic structure containing a nitrogen atom selected from the group consisting of pyridine, pyrimidine, triazine, acridine and pyridazine; X represents a divalent organic group, and a plurality of X present The monosubstituted phenylenediamine represented by the following formula (V); the diaminoorganooxy oxane represented by the following formula (VI); (wherein R ⁷ represents a divalent organic group selected from the group consisting of -O-, -COO-, -OCO-, -NHCO-, -CONH-, and -CO-, and R ⁸ represents a group selected from a steroid skeleton, trifluoro A monovalent organic group of a methyl group and a fluorine group or an alkyl group having 6 to 30 carbon atoms.

(wherein R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ⁹ groups may be the same or different, p is an integer of 1 to 3, and q is an integer of 1 to 20); Compounds represented by (9) to (13). These diamine compounds may be used singly or in combination of plural kinds.

(where y is an integer from 2 to 12, and z is an integer from 1 to 5).

Among them, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,7-diaminopurine are preferred. , 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 9,9-bis(4-aminophenyl)anthracene, 2,2 - bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4-aminophenyl]hexafluoropropane, 4,4'-(p-phenylene diiso) Propyl)diphenylamine, 4,4'-(m-phenylene diisopropylidene)diphenylamine, 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 formula (9) to (13), 2,6- a compound represented by the following formula (14) in the compound represented by the above formula (III), diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, and the above The compound represented by the following formula (15) and the compound represented by the following formula (16) to (21) in the compound represented by the above formula (V) among the compounds represented by the formula (IV).

[Synthesis reaction of poly-proline]

The ratio of use of the tetracarboxylic dianhydride to the diamine compound to be supplied to the polyaminic acid synthesis reaction is preferably from 0.2 to 2.0 based on the amino group contained in one equivalent of the diamine compound. The ratio of the equivalent is more preferably a ratio of 0.3 to 1.2 equivalents.

The synthesis reaction of polylysine is carried out usually in an organic solvent at a temperature of from -20 to 150 ° C, more preferably from 0 to 100 ° C. Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized polyaminic acid, and examples thereof include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N,N. - aprotic polar solvents such as dimethylformamide, dimethyl hydrazine, γ-butyrolactone, tetramethylurea, hexamethylphosphonium triamine; m-methylphenol, xylenol, phenol, halogen A phenolic solvent such as phenol. Further, the amount (a) of the organic solvent is usually preferably an amount such that the total amount (b) of the tetracarboxylic dianhydride and the diamine compound is from 0.1 to 30% by weight based on the total amount (a+b) of the reaction solution.

[poor solvent]

Further, in the range in which the produced polyaminic acid is not precipitated, a poor solvent alcohol, a ketone, an ester, an ether, a halogenated hydrocarbon, or a hydrocarbon of polyamic acid may be used in combination in the above organic solvent. Wait. Specific examples of such a poor solvent include methanol, ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, and lactic acid. Ethyl ester, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethoxy propyl Ethyl acetate, diethyl oxalate, diethyl malonate, diethyl ether, Ethylene glycol methyl ether, ethylene glycol ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol Methyl 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-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, and the like.

As described above, a reaction solution in which polylysine was dissolved was obtained. Then, the reaction solution was poured into a large amount of poor solvent to obtain a precipitate. The polyamine acid is obtained by drying the precipitate under reduced pressure. Further, the polylysine is again dissolved in an organic solvent, and then precipitated with a poor solvent, and the polyamic acid can be purified by performing one or several steps.

[醯i-imidized polymer]

The quinone imidized polymer constituting the liquid crystal alignment agent of the present invention can be obtained by dehydrating and ring-closing the above polyamic acid. The dehydration ring closure of polylysine may be carried out by (i) heating the poly-proline, or (ii) dissolving the poly-proline in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst to the solution and heating as needed. The method is carried out.

The reaction temperature of the above method (i) for heating poly-proline is usually 50 to 200 ° C, preferably 60 to 170 ° C. When the reaction temperature is less than 50 ° C, the dehydration ring-closure reaction cannot be completed. If the reaction temperature exceeds 200 ° C, the molecular weight of the obtained quinone imidized polymer may decrease.

On the other hand, in the method of adding a dehydrating agent and a dehydration ring-closure catalyst to the polyamido acid solution of the above (ii), as the dehydrating agent, for example, for example, Anhydride such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride. The amount of the dehydrating agent is preferably 0.01 to 20 moles per 1 mole of the polyamido acid repeating unit. Further, as the dehydration ring-closure catalyst, for example, a tertiary amine such as pyridine, trimethylpyridine, lutidine or triethylamine can be used. However, it is not limited to these. The amount of the dehydration ring-closing catalyst is preferably from 0.01 to 10 mols per mol of the dehydrating agent used. In addition, examples of the organic solvent used in the dehydration ring closure reaction include an organic solvent exemplified as a solvent used in the synthesis of polylysine. Further, the reaction temperature of the dehydration ring closure reaction is usually from 0 to 180 ° C, preferably from 10 to 150 ° C. Further, the ruthenium iodide polymer can be purified by performing the same operation as the polyamic acid purification method on the reaction solution thus obtained.

[partial quinone]

<polyimine containing quinone imine>

The ruthenium group-containing polyphthalic acid used in the present invention is a structure obtained by imidating a polyamidino group, and the ruthenium group-containing polyphthalic acid used in the present invention is preferably The oxime imidization ratio is 30% or more, more preferably 50% or more. Here, the "rhodium imidization ratio" means a value expressed as a percentage of the ratio of the number of repeating units forming the quinone ring with respect to the total number of repeating units in the polymer. At this time, a part of the quinone ring may also be an isoindole ring.

As a method of synthesizing the ruthenium group containing ruthenium group, (i) a method of synthesizing a polyhydric acid by partially heating and dehydrating the ring, (ii) dissolving the above polyamine in an organic solvent can be used. In the middle, a dehydrating agent and a dehydration ring-closing catalyst are added to the solution and heated to partially dehydrate the mixture as needed. A method of synthesizing by ring, or (iii) a method of synthesizing by mixing a tetracarboxylic dianhydride, a diamine compound, and a diisocyanate compound, and heating and condensing as needed.

In the above method (i), the reaction temperature is usually 300 ° C or lower, preferably 100 to 250 ° C. If the reaction temperature exceeds 300 ° C, the molecular weight of the obtained quinone imine group-containing polyaminic acid may decrease.

On the other hand, as the dehydrating agent used in the method (ii) above, an acid anhydride such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride can be used. The amount of the dehydrating agent is preferably 0.2 to 20 moles per 1 mole of the polyglycine repeating unit. Further, as the dehydration ring-closure catalyst, for example, a tertiary amine such as pyridine, trimethylpyridine, lutidine or triethylamine can be used. However, it is not limited to these. Further, the amount of the ruthenium iodide catalyst is preferably from 0.1 to 10 mols per mol of the dehydrating agent used. In addition, examples of the organic solvent used in the dehydration ring closure reaction include an organic solvent exemplified as a solvent used in the synthesis of polylysine. Further, the reaction temperature of the dehydration ring closure is usually from 0 to 180 ° C, preferably from 60 to 150 ° C. Further, by carrying out the same operation as the polyamic acid purification method on the reaction solution thus obtained, the polyamido acid containing the quinone imine group can be purified.

Specific examples of the diisocyanate compound used in the reaction of the above (iii) include aliphatic diisocyanates such as hexamethylene diisocyanate; cyclohexane-1,2-diisocyanate and 1-methylcyclohexane- 2,4-diisocyanate, 1,2-dimethylcyclohexane-ω,ω'-diisocyanate, 1,4-dimethylcyclohexane-ω,ω'-diisocyanate, isophorone II Isocyanate, 1,3,5-trimethyl-2-propylcyclohexane-1ω, 2ω-diisocyanate, dicyclohexylmethane An alicyclic diisocyanate such as -4,4'-diisocyanate; diphenylmethane-4,4'-diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1- Methyl-2,4-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, or an aromatic diisocyanate such as a diisocyanate represented by the following formulas (22) to (26).

Among them, preferred are dicyclohexylmethane-4,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, 1-methyl-2,4-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate. They can be used singly or in combination of plural kinds. Further, the reaction of the above (iii) is not particularly necessary, and the reaction temperature is usually from 50 to 200 ° C, preferably from 100 to 160 ° C.

[end modification]

<End modified polymer>

The polyamic acid and the ruthenium group-containing polyphthalic acid may also be a terminal-modified polymer having a molecular weight adjusted. By using the terminal-modified polymer, the coating properties and the like of the liquid crystal alignment agent can be improved without impairing the effects of the present invention. Such a terminal-modified polymer can be synthesized by adding a monobasic acid anhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system during the synthesis of poly-proline. Among them, examples of the monobasic acid anhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride, n-hexadecyl group. Succinic anhydride and the like. Further, examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-decylamine, n-decylamine, n-undecylamine, and Dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecaneamine, n-octadecylamine, n-icosylamine, and the like. Further, examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

[logarithmic viscosity]

<Logarithmic Viscosity of Polymer>

The polyamic acid and the ruthenium group-containing polyphthalic acid obtained as above have a logarithmic viscosity (η ln) value of usually 0.05 to 10 dl/g, preferably 0.05 to 5 dl/g.

In the present invention, the logarithmic viscosity (η ln) value is obtained by measuring the viscosity of a solution having a concentration of 0.5 g/100 ml at 30 ° C by using N-methyl-2-pyrrolidone as a solvent, and is obtained by the following formula (i). value.

[Liquid alignment agent]

The liquid crystal alignment agent of the present invention is usually composed of the above polymer dissolved in an organic solvent. Further, in the polymer constituting the liquid crystal alignment agent of the present invention, the ratio of the repeating unit represented by the above formula (I-2) to the repeating unit represented by the above formula (I-1) is preferably 1:9 to 5: 5.

The organic solvent constituting the liquid crystal alignment agent of the present invention may, for example, be a solvent exemplified as a solvent used in the polyamido acid synthesis reaction. In addition, a poor solvent exemplified as a solvent which can be used in combination in the polyamic acid synthesis reaction can be appropriately selected and used in combination.

The solid content concentration in the liquid crystal alignment agent of the present invention is selected in consideration of viscosity, volatility, etc., and is preferably in the range of 1 to 10% by weight. In other words, the liquid crystal alignment agent of the present invention is applied to the surface of the substrate to form a coating film as a liquid crystal alignment film. When the solid content concentration is less than 1% by weight, the thickness of the coating film is too small, and it is difficult to obtain a favorable liquid crystal alignment film. When the solid content concentration exceeds 10% by weight, the thickness of the coating film is too thick, and it is difficult to obtain a favorable liquid crystal alignment film, and when the viscosity of the liquid crystal alignment agent is increased, the coating property is likely to be deteriorated. Further, the temperature at which the liquid crystal alignment agent of the present invention is prepared is preferably from 0 ° C to 200 ° C, more preferably from 20 ° C to 60 ° C.

The liquid crystal alignment agent of the present invention contains at least 2 parts by weight of a compound having four epoxy groups in the molecule (hereinafter also referred to as "epoxy group-containing compound") with respect to 100 parts by weight of the specific polymer.

As the epoxy group-containing compound, preferred examples include, for example, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-di(N ,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N '-Tetraglycidyl-4,4'-diaminodiphenyl ether, N,N,N',N'-tetraglycidyl-p-xylyleneamine, N,N,N',N' -tetraglycidyl-3,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-1,3-propanediamine, N,N,N',N' -tetraglycidyl-4,4'-diaminoheptanediamine, 1,3-bis(N,N-diglycidylaminoethyl)cyclohexane, N,N,N',N'-four Glycidyl-2,2'-dimethyl-4,4'-diaminobiphenyl, and the like. The content of the epoxy compound is preferably 2 to 40 parts by weight, more preferably 5 to 30 parts by weight, per 100 parts by weight of the specific polymer contained in the alignment agent.

Further, the liquid crystal alignment agent of the present invention may further contain a compound having a functional decane (hereinafter also referred to as "decane coupling agent"). The decane coupling agent is preferably a decane coupling agent represented by the following formula (I-4), YR ³ SiR _3-m X _m (I-4) (wherein Y is an organic group having an amino group, R ³ Is a divalent hydrocarbon group having 1 to 10 carbon atoms, R is an alkyl group having 1 to 5 carbon atoms, X is an alkoxy group represented by OR ⁴ or an alkoxycarbonyl group represented by OCOR ⁵ (wherein R ⁴ and R ^{5 are)} It is an alkyl group having 1 to 10 carbon atoms, and m is an integer of 1 to 3).

As such a decane coupling agent, for example, 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 2-aminopropyltrimethoxydecane, 2-aminopropyltriethoxy group can be mentioned. Decane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldi Methoxydecane, 3-ureidopropyltrimethoxydecane, 3-ureidopropyltriethoxydecane, N-ethoxycarbonyl-3-aminopropyltrimethoxydecane, N-ethoxycarbonyl- 3-aminopropyltriethoxydecane, N-triethoxydecylpropyltriethylenetriamine, N-trimethoxydecylpropyltriethylenetriamine, 10-trimethoxydecyl- 1,4,7-triazanonane, 10-triethoxydecyl-1,4,7-triazadecane, 9-trimethoxydecyl-3,6-diazaindole Acetate, 9-triethoxydecyl-3,6-diazaindolyl acetate, N-benzyl-3-aminopropyltrimethoxydecane, N-benzyl-3-aminopropane Triethoxy decane, N-phenyl-3-aminopropyltrimethoxydecane, N-phenyl-3-aminopropyltriethoxydecane, N-bis(oxyvinyl)-3-amino Propyltrimethoxydecane, N-bis(oxyvinyl)-3-aminopropyltriethoxydecane, 3-glycidoxypropyltrimethoxydecane, 3-[2-(3-trimethyl) Oxyalkyl propylaminopropyl)ethylamino]propionic acid methyl ester or the like.

The mixing ratio of these decane coupling agents is usually 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight, more preferably 0.5 to 2 parts by weight, per 100 parts by weight of the specific polymer. If it is less than 0.01 part by weight, the effect of improving the printability may be insufficient, and if it exceeds 5 parts by weight, the viscosity may increase.

<Liquid crystal display element>

The liquid crystal display element obtained by using the liquid crystal alignment agent of the present invention can be produced, for example, by the following method.

(1) The liquid crystal alignment agent of the present invention is applied onto one surface of a substrate on which a patterned transparent conductive film is provided by, for example, a roll coater method, a spin coater method, a printing method, an inkjet method, or the like, and then passed through The coated surface is heated to form a coating film. Among them, as the substrate, for example, glass such as float glass or soda lime glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether fluorene or polycarbonate can be used. As the transparent conductive film provided on one side of the substrate, a NESA film made of tin oxide (SnO ₂ ) (registered trademark of PPG, USA), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ), or the like can be used. . Patterning of these transparent conductive films may be performed by photolithography and a method of using a mask in advance. At the time of application of the liquid crystal alignment agent, in order to further improve the adhesion between the substrate surface and the transparent conductive film and the coating film, a functional decane-containing compound or a functional titanium-containing compound or the like may be applied to the surface of the substrate in advance. The heating temperature after the application of the liquid crystal alignment agent is preferably from 80 to 300 ° C, more preferably from 120 to 250 ° C. Further, the liquid crystal alignment agent of the present invention containing polyglycolic acid can form a coating film as an oriented film by coating, remove the organic solvent, or perform dehydration ring closure by further heating, thereby forming a coating film which is further imidized. The thickness of the formed coating film is usually 0.001 to 1 μm, preferably 0.005 to 0.5 μm.

(2) The surface of the formed coating film is rubbed in a certain direction by a roller wrapped with a fiber cloth such as nylon, rayon, or cotton. Thus, a liquid crystal alignment film which imparts alignment energy to liquid crystal molecules to the coating film is prepared.

In addition, the liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention is subjected to a process of changing the pretilt angle by partially irradiating ultraviolet rays as shown in, for example, JP-A-6-222366 or JP-A-6-281937, or A protective film is partially formed on the surface of the liquid crystal alignment film subjected to the rubbing treatment as shown in Japanese Laid-Open Patent Publication No. Hei 5-105044, and after the rubbing treatment is performed in a direction different from the previous rubbing treatment, the protective film is removed to make the liquid crystal alignment film. The liquid crystal alignment can be changed, whereby the field of view characteristics of the liquid crystal display element can be improved.

(3) manufacturing two substrates in which the liquid crystal alignment film is formed as described above, and placing the two substrates in opposite directions through the gap (cell gap) so that the rubbing directions of the respective liquid crystal alignment films are perpendicular or antiparallel to each other, and the two substrates are surrounded by the substrate. The parts are bonded together with a sealant. The liquid crystal gap is filled into the cell gap separated by the surface of the substrate and the sealant, and the injection hole is closed to form a liquid crystal cell. Then, a polarizing plate is bonded to the outer surface of the liquid crystal cell, that is, the transparent substrate side constituting the liquid crystal cell, to obtain a liquid crystal display element.

Among them, as the sealant, for example, an alumina ball-containing epoxy resin as a curing agent and a separator can be used.

Examples of the liquid crystal include nematic liquid crystal and dish-shaped liquid crystal. Among them, a nematic liquid crystal is preferable, and for example, a Schiff's liquid crystal, an oxidized azo liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, an ester liquid crystal, a terphenyl liquid crystal, or a biphenyl can be used. A cyclohexane liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, a bicyclooctane liquid crystal, a cubic liquid crystal, or the like. Further, in these liquid crystals, a cholesteric liquid crystal such as chlorinated cholesterol, cholesterol citrate or cholesterol carbonate, and a palm-shaped product sold under the trade names "C-15" and "CB-15" (manufactured by Merck) may be added. It is used as a structure agent or the like. Further, a ferroelectric liquid crystal such as p-nonyloxybenzylidene-p-amino-2-methylbutylcinnamate may also be used.

In addition, a polarizing plate which is bonded to the outer surface of the liquid crystal cell, a polarizing plate which is obtained by absorbing iodine while extending the orientation of the polyvinyl alcohol, and which is a polarizing film called an H film, is sandwiched between the protective film of the cellulose acetate or A polarizing plate made of the H film itself.

[Examples]

The invention will be more specifically illustrated by the following examples, but the invention is not limited thereto. The voltage holding ratios in the examples and comparative examples were evaluated in the following manner.

[Voltage retention rate]

In a time span of 167 milliseconds, a voltage of 5 V was applied to the liquid crystal display element, and the voltage application time was 60 microseconds, and the voltage holding ratio from the voltage release to 167 milliseconds was measured. The measuring device used VHR-1 manufactured by Dongyang Science and Technology Co., Ltd. When the voltage holding ratio was 95% or more, it was evaluated as "good", and the other cases were evaluated as "not good".

Synthesis Example 1

224.17 g (1.0 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic acid dianhydride and 108.14 g (1.0 mol) of p-phenylenediamine as diamine compound were dissolved in 4500 g In N-methyl-2-pyrrolidone, the reaction was carried out at 60 ° C for 6 hours. Next, the reaction solution was poured into a large excess of methanol to precipitate a reaction product. Then, it was washed with methanol, and dried at 40 ° C for 15 hours under reduced pressure, thereby obtaining 380 g of polylysine having a logarithmic viscosity of 0.75 dl / g. 30 g of the obtained polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, 23.4 g of pyridine and 18.1 g of acetic anhydride were added, and the mixture was dehydrated and closed at 110 ° C for 4 hours, and precipitated and washed in the same manner as above. Under reduced pressure, 18.2 g of a polyimine having a logarithmic viscosity of 0.68 dl/g (which is referred to as "polyimine (A-1)") was obtained.

Synthesis Example 2

In the same manner as in Synthesis Example 1, except that 198.27 g (1.0 mol) of 4,4'-diaminodiphenylmethane was used as the diamine compound, 390 g of a logarithmic viscosity of 0.55 dl/g was obtained. Polylysine. 30 g of the obtained polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, and 5.7 g of pyridine and 7.4 g of acetic anhydride were added thereto, and the mixture was dehydrated and closed at 110 ° C for 4 hours, and precipitated and washed in the same manner as above. Under reduced pressure, 20.5 g of a polyimine having a logarithmic viscosity of 0.49 dl/g (as "polyimine (A-2)") was obtained.

Synthesis Example 3

In the same manner as in Synthesis Example 1, except that 200.24 g (1.0 mol) of 4,4'-diaminodiphenyl ether was used as the diamine compound, 390 g of a logarithmic viscosity of 0.52 dl/g was obtained. Polylysine. 30 g of the obtained polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, and 5.7 g of pyridine and 7.4 g of acetic anhydride were added thereto, and the mixture was dehydrated and closed at 110 ° C for 4 hours, and precipitated and washed in the same manner as above. Under reduced pressure, 18.5 g of a polyimine having a logarithmic viscosity of 0.48 dl/g (which is referred to as "polyimine (A-3)") was obtained.

Synthesis Example 4

In Synthesis Example 1, the same procedure as in Synthesis Example 1 was carried out except that 75.69 g (0.7 mol) of p-phenylenediamine and 59.48 g (0.3 mol) of 4,4'-diaminodiphenylmethane were used as the diamine compound. The operation was carried out to obtain 390 g of polylysine having a logarithmic viscosity of 0.56 dl/g. 30 g of the obtained polyamic acid was dissolved in 570 g of Nmethyl-2-pyrrolidone, and 5.7 g of pyridine and 7.4 g of acetic anhydride were added thereto, and the mixture was dehydrated and closed at 110 ° C for 4 hours, and precipitated, washed, and reduced in the same manner as above. Under pressure, 17.5 g of a polyimine having a logarithmic viscosity of 0.50 dl/g (which is referred to as "polyimine (A-4)") was obtained.

Synthesis Example 5

In Synthesis Example 1, except that 86.51 g (0.8 mol) of p-phenylenediamine and 40.04 g (0.2 mol) of 4,4'-diaminodiphenyl ether were used as the diamine compound, the same as in Synthesis Example 1. The operation was carried out to obtain 390 g of polylysine having a logarithmic viscosity of 0.70 dl/g. 30 g of the obtained polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, and 5.7 g of pyridine and 7.4 g of acetic anhydride were added thereto, and the mixture was dehydrated and closed at 110 ° C for 4 hours, and precipitated and washed in the same manner as above. Under reduced pressure, 19.8 g of a polyimine having a logarithmic viscosity of 0.61 dl/g (as "polyimine (A-5)") was obtained.

Synthesis Example 6

In Synthesis Example 1, except that 112.08 g (0.5 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 157.14 g (0.5 mol) 1,3,3a, 4,5,9b-six were used. Hydrogen-8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione as tetracarboxylic acid dianhydride In the same manner as in Synthesis Example 1, except that 108.14 g (1.0 mol) of p-phenylenediamine was used as the diamine compound, 390 g of polylysine having a logarithmic viscosity of 0.8 dl/g was obtained. 30 g of the obtained polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, and 5.7 g of pyridine and 7.4 g of acetic anhydride were added thereto, and the mixture was dehydrated and closed at 110 ° C for 4 hours, and precipitated and washed in the same manner as above. Under reduced pressure, 18.3 g of a polyimine having a logarithmic viscosity of 0.68 dl/g (which is referred to as "polyimine (A-6)") was obtained.

Synthesis Example 7

In Synthesis Example 1, except that 86.51 g (0.8 mol) of p-phenylenediamine and 82.1 g (0.2 mol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane were used as two. Other than the amine compound, in the same manner as in Synthesis Example 1, 390 g of polylysine having a logarithmic viscosity of 0.61 dl/g was obtained. 30 g of the obtained polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, and 5.7 g of pyridine and 7.4 g of acetic anhydride were added thereto, and the mixture was dehydrated and closed at 110 ° C for 4 hours, and precipitated, washed, and reduced in the same manner as above. Under pressure, 19.2 g of a polyimine (having a "polyimine (A-7)") having a logarithmic viscosity of 0.53 dl/g was obtained.

Synthesis Example 8

In Synthesis Example 1, except that 112.08 g (0.5 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 157.14 g (0.5 mol) 1,3,3a, 4,5,9b-six were used. Hydrogen-5-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione as tetracarboxylic acid dianhydride 95.71 g (0.885 mol) of p-phenylenediamine and 24.85 g (0.1 mol) of diaminopropyltetramethyldioxane as a diamine compound, 2.793 g (0.03 mol) of aniline as a monoamine. In the same manner as in Synthesis Example 1, 390 g of polylysine having a logarithmic viscosity of 0.85 dl/g was obtained. 30 g of the obtained polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, and 5.7 g of pyridine and 7.4 g of acetic anhydride were added thereto, and the mixture was dehydrated and closed at 110 ° C for 4 hours, and precipitated and washed in the same manner as above. Under reduced pressure, 18.5 g of a polyimine (having a polyimine (A-8)) having a logarithmic viscosity of 0.70 dl/g was obtained.

Example 1

100 parts by weight of the polyimine (A-1) obtained in Synthesis Example 1, 10 parts by weight of N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane And 0.75 parts by weight of methyl 3-[2-(3-trimethoxydecylpropylamino)ethylamino]propanoate dissolved in a mixed solvent of γ-butyrolactone/N-methyl-2-pyrrolidone (weight ratio) In 90/10), a solution having a solid concentration of 4% by weight was prepared, and after sufficiently stirring, the solution was filtered through a filter having a pore size of 1 μm to prepare a liquid crystal alignment agent of the present invention. The liquid crystal alignment agent of the present invention prepared as described above was applied onto a transparent conductive film made of an ITO film having a shape of 1 mm on a glass substrate having a thickness of 1 mm by a spin coater, and dried at 180 ° C for 1 hour to form a dry film thickness. It is a coating of 0.08 μm. The formed coating film surface was subjected to a rubbing treatment using a rubbing machine equipped with a roller wound with a nylon cloth to prepare a liquid crystal alignment film. Among them, the rubbing treatment conditions were: a roll rotation speed of 400 rpm, a stage moving speed of 3 cm/sec, and a pile extrusion length of 0.4 mm. (This substrate serves as "substrate A").

The liquid crystal alignment agent of the present invention prepared as described above was applied onto one surface of a glass substrate having a thickness of 1 mm by a spin coater, and dried at 180 ° C for 1 hour to form a coating film having a dry film thickness of 0.08 μm. When the substrate was observed under a microscope having a magnification of 20, no unevenness in printing and pinhole defects were observed, and the printability was good.

The formed coating film surface was rubbed with a friction machine equipped with a roller wound with a nylon cloth to prepare a liquid crystal alignment film. Among them, the rubbing treatment conditions were: the roller rotation speed was 400 rpm, the table movement speed was 3 cm/sec, and the pile extrusion length was 0.4 mm. (This substrate serves as "substrate B").

At the outer edge portion of the coating film faces of the substrates A and B, an epoxy resin binder containing alumina balls having a diameter of 17 μm is applied by screen printing, and the rubbing directions in the respective liquid crystal alignment films are reversed. Parallelly, two substrates are disposed oppositely through the gap, and the outer edge portions are brought into contact with each other to press and cure the adhesive.

Then, a nematic liquid crystal (MLC-2019, manufactured by Merck) was filled between the pair of substrates through the liquid crystal injection port, and then the liquid crystal injection port was closed with an epoxy-based adhesive, and the polarizing plate was attached to both sides of the substrate. The polarization direction of the polarizing plate is made to match the rubbing direction of the liquid crystal alignment film of the respective substrates to form a liquid crystal display element.

The voltage holding ratio of the obtained liquid crystal display element was evaluated. The voltage holding ratio showed a good value of 95% or more, and no unevenness in contrast and display defects after voltage application were found.

Examples 2 to 8 and Comparative Examples 1 to 3

The polyimine (A-2) to (A-8), various epoxy group-containing compounds and decane coupling agents prepared in Synthesis Examples 2 to 8 are dissolved in γ-butyrolactone as a main component. A solution having a solid concentration of 4.0% was prepared in the mixed solvent, and the solution was filtered through a filter having a pore size of 1 μm to prepare a liquid crystal alignment agent of the present invention, and a coating was formed on the substrate in the same manner as in Example 1. The film was observed for the presence or absence of uneven printing and small hole defects, and further formed into a liquid crystal display element, and the voltage holding ratio was evaluated. The results are shown in Table 1.

Claims (5)

A liquid crystal alignment agent for a liquid crystal display device of a horizontal electric field type, which comprises (A) a polymer or a molecule having a repeating unit represented by the following formula (I-1) and a repeating unit represented by the following formula (I-2) a compound having four epoxy groups and a functional decane compound, and the repeating unit represented by the following formula (I-1) in the (A) polymer: a ratio of repeating units represented by the following formula (I-2) It is 1:9 to 5:5, and the content of the compound having 4 epoxy groups in the molecule is 2 to 40 parts by weight with respect to 100 parts by weight of the (A) polymer, and the content of the functional decane compound is 0.01 to 5 parts by weight, the (A) polymer is a part in which the repeating unit represented by the following formula (I-1) and the repeating unit represented by the following formula (I-2) are combined in the same molecule. An imidized polymer, the (A) polymer system does not contain poly-proline, In the formula, P ¹ is a tetravalent organic group, and Q ¹ is a divalent organic group. In the formula, P ² is a tetravalent organic group which may be different or identical to P ¹ , and Q ² is a divalent organic group. The liquid crystal alignment agent for a horizontal electric field type liquid crystal display device according to the first aspect of the invention, wherein the compound having four epoxy groups in the molecule is selected from the group consisting of compounds represented by the following formula (I-3). At least one epoxy-containing compound, In the formula, R ² represents a divalent organic group. The liquid crystal alignment agent for a horizontal electric field type liquid crystal display device according to the first aspect of the invention, wherein the functional decane compound is a decane coupling agent selected from the group consisting of compounds represented by the following formula (I-4), YR ³ In the formula of SiR _3-m X _m (I-4), Y is an organic group having an amine group, R ³ is a divalent hydrocarbon group having 1 to 10 carbon atoms, and R is an alkane having 1 to 5 carbon atoms. A group, X represents an alkoxy group represented by OR ⁴ or an alkoxycarbonyl group represented by OCOR ⁵ , wherein R ⁴ and R ⁵ are an alkyl group having 1 to 10 carbon atoms, and m represents an integer of 1 to 3. The liquid crystal alignment agent for a horizontal electric field type liquid crystal display element according to any one of claims 1 to 3, wherein the tetracarboxylic dianhydride which produces the polymer (A) comprises 1,2,3,4-cyclobutane Tetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3, 3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione or 1 ,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan- Any one of 1,3-diketone and pyromellitic anhydride. The liquid crystal alignment agent for a horizontal electric field type liquid crystal display device according to any one of claims 1 to 3, which is used for producing a liquid crystal alignment film for a horizontal electric field type liquid crystal display device.