TWI427375B - Vertical alignment mode liquid crystal alignment agent and liquid crystal display device - Google Patents

Description

Vertical alignment type liquid crystal alignment agent and liquid crystal display element

The present invention relates to a vertical alignment type liquid crystal alignment agent and a liquid crystal display element, and more particularly to a vertical alignment type liquid crystal alignment agent excellent in printability and vertical alignment, and a liquid crystal display element obtained from the vertical alignment type liquid crystal alignment agent.

In the past, liquid crystal cells such as TN (Twisted Nematic), STN (Super Twisted Nematic), and IPS (In Plane Switching) type liquid crystals have been known as liquid crystal display elements. a display element which forms a liquid crystal alignment film on the surface of a substrate on which a transparent conductive film is provided, and as a substrate for a liquid crystal display element, two sheets of the substrate are disposed opposite each other to form positive dielectric anisotropy in a gap therebetween The nematic liquid crystal layer constitutes a unit cell of a sandwich structure, and the long axis of the liquid crystal molecules is continuously twisted from one substrate to the other substrate by 0 to 360 degrees (refer to Patent Document 1 and Patent Document 2).

In such a liquid crystal cell, the liquid crystal alignment film is usually formed by a method of rubbing the surface of the organic film formed on the surface of the substrate in one direction with a cloth such as rayon (grinding method). As such an organic film, a film obtained from a polyimine resin prepared by subjecting a diamine compound to a dianhydride to undergo a polycondensation reaction is widely used from the viewpoint of heat resistance and electrical properties.

However, for liquid crystal cells such as TN (Twisted Nematic) type and STN (Super Twisted Nematic) type, the liquid crystal alignment film must have a liquid crystal molecule inclined at a certain angle (usually 3 to 10 Å) with respect to the substrate surface. Pretilt performance. Here, the "pretilt angle" as used herein means an angle at which liquid crystal molecules are inclined from a direction parallel to a substrate surface.

Further, as an operation mode of the liquid crystal display element different from the above, a homeotropic alignment method in which liquid crystal molecules having negative dielectric anisotropy are perpendicular to the substrate, that is, a pretilt angle of about 90 Å is known. In this mode of operation, once a voltage is applied between the substrates, the liquid crystal molecules are tilted from the normal direction of the substrate toward one direction in the substrate surface.

It is known that in order to exhibit the high pretilt angle required for these various modes, the liquid crystal alignment film may be a polyimine resin having a bulky substituent such as octadecyl group. Among such substituents, a group having a large volume and having a rigid steroid skeleton is particularly advantageous because it can exhibit a high pretilt angle. Such a polyimine resin having a large volume of a substituent can be produced by using a diamine compound having a bulky substituent or a dianhydride in the synthesis thereof.

In addition, in recent years, as liquid crystal display elements have become larger, the liquid crystal alignment film has to be formed into a large area. Therefore, the liquid crystal alignment agent for forming a liquid crystal alignment film is required to have further improved printability (coating property).

[Patent Document 1] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. [Patent Document 5] Japanese Patent Laid-Open Publication No. 2006-010896

An object of the present invention is to provide a vertical alignment type liquid crystal alignment agent excellent in printability and vertical alignment.

Another object of the present invention is to provide a liquid crystal display element having a liquid crystal alignment film produced by the above liquid crystal alignment agent.

The vertical alignment type liquid crystal alignment agent of the present invention is characterized by comprising a polymer consisting of at least one group consisting of repeating units each represented by the following formula (I-1) and the following formula (I-2) a repeating unit selected from the group consisting of at least one of the divalent organic groups represented by the following formula (II-1) and formula (II-2) as the following formula (I-1) and Q in the following formula ^{(I-2) Q 1 2} ; mixed solvent, the mixed solvent comprising: selected from N- methyl-2-pyrrolidone, [gamma] -butyrolactone, 1,3-bis a solvent A composed of at least one of methyl-2-imidazolidinone, N,N-dimethylformamide, and N,N-dimethylacetamide; selected from the group consisting of butyl sirosu, two a solvent B composed of at least one of acetol, propylene carbonate, diethylene glycol diethyl ether and ethyl 3-ethoxypropionate; and a compound selected from the group consisting of compounds represented by the following formula (III) At least one solvent C is formed.

(In the formula (I-1), P ¹ is a tetravalent organic group derived from a tetracarboxylic acid, and Q ¹ is a divalent organic group derived from a diamine compound. Further, in the formula (I-2), P ² is a tetravalent organic group derived from a tetracarboxylic acid, and Q ² is a divalent organic group derived from a diamine compound.)

(In the formula (II-1), X ¹ is a single bond, -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH-, -S-, methylene, and the carbon number is 2 to 6 alkyl or phenyl, R ¹ is an alkyl group having 10 to 20 carbon atoms, a monovalent organic group having an alicyclic skeleton having a carbon number of 4 to 40, or a carbon number of 6 to 20 a monovalent organic group of a fluorine-containing atom, and, in the formula (II-2), X ¹ is a single bond, -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH- , -S-, methylene, an alkyl group having a carbon number of 2 to 6 or a phenyl group, and R ² is a divalent organic group having an alicyclic skeleton having a carbon number of 4 to 40 or a carbon number of 5 ~30 of a fluorine atom-containing divalent organic group.)

(In the formula (III), Z is -O-, -CO- or -COO-, and each of R ³ and R ⁴ is a monovalent hydrocarbon group, and the total carbon number of R ³ and R ⁴ is 6 to 10.

In the present invention, the boiling point of the solvent C is preferably 140 ° C or higher.

Further, the solvent C preferably satisfies any of the following conditions (1) to (3).

(1) A compound wherein Z is -O- in the formula (III), and the carbon number of R ³ and R ⁴ is 6 to 10 in total.

(2) A compound of the formula (III) wherein Z is -CO- and the carbon number of R ³ and R ⁴ is 8 in total.

(3) A compound of the formula (III) wherein Z is -COO- and the carbon numbers of R ³ and R ⁴ are 6 to 9 in total.

Further, the solvent C preferably satisfies any of the following conditions (4) to (6).

(4) A compound wherein Z is -O- in the formula (III) and the carbon number of R ³ and R ⁴ is 6 to 10 in total, and the surface tension is 25 mN/m or less.

(5) A compound of the formula (III) wherein Z is -CO- and the carbon number of R ³ and R ⁴ is 8 in total, and the surface tension is 24 mN/m or less.

(6) A compound of the formula (III) wherein Z is -COO- and the carbon number of R ³ and R ⁴ is 6 to 9 in total, and the surface tension is 26 mN/m or less.

Further, the content ratio of the solvent C in the mixed solvent is preferably from 0.1 to 40% by weight.

The liquid crystal display device of the present invention is characterized by having a vertical alignment type liquid crystal alignment film obtained by the above-described vertical alignment type liquid crystal alignment agent.

According to the vertical type liquid crystal alignment agent of the present invention, excellent printability can be obtained, and a liquid crystal alignment film excellent in vertical alignment can be formed.

The liquid crystal display element of the present invention can be effectively used in various devices, for example, can be applied to a desktop computer, a watch, a desk clock, a mobile phone, a counting display screen, a word processor, a personal computer, a liquid crystal television, etc. Display device.

Hereinafter, the present invention will be specifically described.

The vertical alignment type liquid crystal alignment agent (hereinafter also referred to as "liquid crystal alignment agent") according to the present invention includes a reaction of a tetracarboxylic dianhydride and a diamine compound. A polymer and a mixed solvent of the obtained repeating unit represented by the above formula (I-1) or formula (I-2).

A polymer containing a repeating unit represented by the above formula (I-1) in the above repeating unit (hereinafter also referred to as "specific polyphthalic acid polymer") can usually be obtained by making a tetracarboxylic dianhydride and a diamine compound organic It is prepared by reacting in a solvent. Further, the polymer containing the repeating unit represented by the above formula (I-2) (hereinafter also referred to as "specific polyimine polymer") can be obtained by dehydrating and ring-closing the glycine moiety of the specific polyaminic acid polymer. be made of.

Hereinafter, a method for producing a specific polyamine polymer and a specific polyimine polymer constituting the liquid crystal alignment agent of the present invention will be described.

[tetracarboxylic dianhydride]

As the tetracarboxylic dianhydride which can be used for preparing the specific polyaminic acid polymer and/or the specific polyimine polymer constituting the liquid crystal alignment agent of the present invention, for example, butane tetracarboxylic dianhydride, 1 , 2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-diethyl-1 , 2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-diethyl-1 , 2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetra 1,2-,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid Dihydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,2,4-tricarboxycyclopentyl acetic acid Anhydride, bicyclo[2,2,1]-heptane-2,3,5,6-tetracarboxylic dianhydride, 3,5,6-tricarboxynorbornane-2-acetic acid dianhydride, tetracyclo[4 , 4,0,1 ^2,5 ,1 ^7,10 ]dodecane-3,4,8,9-tetracarboxylic 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-methyl- 5(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-six Hydrogen-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-dione 1,3,3a,4,5,9b-hexahydro-7-ethyl-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-8-ethyl-5(tetrahydro-2,5-dioxo-3 -furyl)-naphthalene [1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5,8-dimethyl-5(tetrahydrogen) -2,5-dioxo-3-furanyl)-naphthalene [1,2-c]-furan-1,3-dione, 5-(2,5-dioxotetrahydrofuranmethylene)-3 -methyl-3 -cyclohexene-1,2-dicarboxylic anhydride, bicyclo[2,2,2]-oct-4-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2,2,2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, aliphatic and alicyclic tetracarboxylic dianhydrides such as compounds represented by the following formulas (1) and (2); Acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenylindole tetracarboxylic dianhydride, 1,4,5,8 -naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4, 4'-Dimethyldiphenylnonanetetracarboxylic dianhydride, 3,3',4,4'-tetraphenylnonanetetracarboxylic dianhydride, 1,2,3,4-furan tetracarboxylic dianhydride 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylphosphonium dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, 3,3',4,4'-perfluoroisopropylidene diphthalic dianhydride, 3,3 ',4,4'-biphenyltetracarboxylic dianhydride, di(phthalic acid)benzenephosphine oxide dianhydride, ethylene glycol-di(hydroper trimellitate), propylene glycol-di(dehydrated trimellitic acid) Acid ester), 1,4-butanediol-di(dehydrated benzotriene) Acid ester), 1,6-hexanediol-di(hydroper trimellitate), 1,8-octanediol-di(hydrogen trimellitate), 2,2-bis(4-hydroxybenzene) An aromatic tetracarboxylic dianhydride such as a compound represented by the following formulas (3) to (6) and a propane-di(hydrogen trimellitate). They may be used alone or in combination of two or more.

(wherein R ¹¹ and R ¹² represent a divalent organic group having an aromatic ring, R ⁴ and R ⁵ represent a hydrogen atom or an alkyl group, and a plurality of R ⁴ and R ^{5 present} may be the same or different.)

Among them, it is preferable to contain 50 mol% or more of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,2-dimethyl-1,2 with respect to all tetracarboxylic dianhydride. , 3,4-cyclobutane tetracarboxylic dianhydride, 1,2-diethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2 , 3,4-cyclobutane tetracarboxylic dianhydride, 1,3-diethyl-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, bicyclo[2,2,1] - heptane-2,3,5,6-tetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid Anhydride, 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-methyl-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- Furyl)-naphthalene [1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-7-ethyl-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-diketone, 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-hexahydro-5,8-dimethyl-5(tetrahydro-2,5-dioxo- At least one alicyclic tetracarboxylic dianhydride in 3-furyl)-naphthalene [1,2-c]-furan-1,3-dione, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride From the viewpoint of improving performance, it is more preferably 70% by mole or more.

[diamine compound]

Q ¹ and Q ² in the repeating unit represented by the above formula (I-1) and the above formula (I-2) (hereinafter referred to as "specific repeating unit") are organic groups derived from a diamine compound, equivalent to two The amine compound removes the residues of the two amine groups. In the present invention, a polymer containing a repeating unit having at least one of the organic groups represented by the above formula (II-1) and the above formula (II-2) as Q ¹ and Q ^{2 is used} .

In the above formula (II-1), R ¹ is an alkyl group having 10 to 20 carbon atoms, a monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms, or a fluorine having 6 to 20 carbon atoms. A monovalent organic group of an atom.

Here, examples of the alkyl group having 10 to 20 carbon atoms include n-decyl, n-dodecyl, n-pentadecyl, n-hexadecyl, n-octadecyl, n-icosyl. Wait.

In addition, examples of the monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms include an alicyclic ring derived from a cycloalkane such as cyclobutane, cyclopentane, cyclohexane or cyclodecane. Skeleton; norbornane, adamantane, etc. A bridged alicyclic skeleton; a monovalent organic group of a steroid skeleton such as cholesterol or cholestyl alcohol. The above monovalent organic group having an alicyclic skeleton may also be a group substituted by a halogen atom, preferably a fluorine atom.

In addition, examples of the monovalent organic group having a fluorine atom having 6 to 20 carbon atoms include straight-chain alkyl groups having 6 to 20 carbon atoms such as n-hexyl group, n-octyl group and n-decyl group; An alicyclic hydrocarbon group having 6 to 20 carbon atoms such as a cyclooctyl group; a part or all of hydrogen atoms in an organic group such as an aromatic hydrocarbon group having 6 to 20 carbon atoms such as a phenyl group or a biphenyl group; A fluoroalkyl or fluoroalkoxy-substituted group.

Further, in the above formula (II-1), the group represented by X ¹ is a single bond, -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH-.-S-, and methylene The alkyl group having a carbon number of 2 to 6 and a phenyl group are particularly preferred, and examples thereof include a group represented by -O-, -CO-, -COO-, and -OCO-.

Specific examples of the diamine compound having the group represented by the above (II-1) include dodecyloxy-2,4-diaminobenzene and pentadecyloxy-2,4. -diaminobenzene, hexadecyloxy-2,4-diaminobenzene, octadecyloxy-2,4-diaminobenzene, a compound represented by the following formulas (7) to (22).

In the above formula (II-2), R ² is a divalent organic group having a condensed ring-shaped divalent organic group having 4 to 40 carbon atoms or a fluorine atom having 5 to 30 carbon atoms.

Here, examples of the divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms include an alicyclic ring derived from a cycloalkane such as cyclobutane, cyclopentane, cyclohexane or cyclodecane. A skeleton having a bridged alicyclic skeleton such as norbornane or adamantane; a divalent organic group having a steroid skeleton such as cholesterol or cholalkanol; and the like. The above divalent organic group having an alicyclic skeleton may also be a group substituted by a halogen atom, preferably a fluorine atom.

Further, specific examples of the divalent organic group having a fluorine atom having 5 to 30 carbon atoms include a linear alkyl group having 5 to 30 carbon atoms such as n-hexyl, n-octyl or n-decyl; An alicyclic hydrocarbon group having a carbon number of 5 to 30 such as a hexyl group or a cyclooctyl group; or a part or all of hydrogen atoms in an organic group such as an aromatic hydrocarbon group having a carbon number of 6 to 30 such as a phenyl group or a biphenyl group; A group substituted with an atom or a fluoroalkyl group.

Specific examples of the diamine compound having a group represented by the above formula (II-2) include compounds represented by the following formulas (23) to (27).

In the specific polyaminic acid polymer and/or the specific polyimine polymer used in the present invention, the ratio of the specific repeating unit is preferably 7 moles in all the repeating units from the viewpoint of the vertical alignment property. More than %, more preferably 10% by mole or more.

In the synthesis of the specific polyaminic acid polymer and/or the specific polyimine polymer used in the present invention, the above formula (II-1) or the above may be contained within the range not impairing the effects of the present invention. A group other than the divalent organic group represented by the formula (II-2) is a repeating unit of Q ¹ and Q ² (hereinafter referred to as "other repeating unit").

As the diamine compound for obtaining other repeating units, for example, p-phenylenediamine, 2-methyl-1,4-phenylenediamine, 2-ethyl-1,4-phenylenediamine, 2, 5 may be mentioned. - dimethyl-1,4-phenylenediamine, 2,5-diethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, Phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylanthracene, 2,2'-dimethyl- 4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-diethyl-4,4'-di Aminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3 , 3'-diethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzimidamide, 4,4'-diaminodiphenyl ether, 1,5-di Amino naphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 5-amino-1-(4'-aminophenyl)-1,3,3-trimethyl Indane, 6-amino-1-(4'-aminophenyl)-1,3,3-trimethylindan, 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)propane, 2,2-di(4- Aminophenyl) hexafluoropropane, 2,2-di[ 4-(4-Aminophenoxy)phenyl]anthracene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1, 3-bis(3-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)-10-hydroquinone, 2,7-diaminopurine, 9,9-di(4- Aminophenyl)anthracene, 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-phenylene isopropylidene)diphenylamine, 4,4'-(meta-phenylisopropylene)diphenylamine, 2,2'-bis[4-(4-amino -2-trifluoromethylphenoxy)phenyl]hexafluoropropane, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-di[( Aromatic diamines such as 4-amino-2-trifluoromethyl)phenoxy]-octafluorobiphenyl, 4-(4-n-heptylcyclohexyl)phenoxy-2,4-diaminobenzene ; 1,3-bis(aminomethyl)benzene, 1,3-propanediamine, butanediamine, pentanediamine, hexamethylenediamine, heptanediamine, octanediamine, decanediamine, 4,4-diamine Aliphatic diamines such as hexyl heptane diamine; 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-di Amino-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 6,6-Diamino-2-ethoxyacridine lactate, 3,8-diamino-6-phenylphenanthridine, 1,4-diaminopyridazine, 3,6-di Amino acridine, bis(4-amine (30) the following compounds of formula (28) represents the ~; phenyl) diphenylamine molecule within a diamine having a nitrogen atom other than the two-stage 1 and stage 1 amine group.

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

(wherein R ⁶ represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ⁶ groups may be the same or different, p is an integer of 1 to 3, q is an integer of 1 to 20, and y is 2 to 12 The integer, z is an integer from 1 to 5.)

Among them, preferred examples thereof include p-phenylenediamine, 2-methyl-1,4-phenylenediamine, 2-ethyl-1,4-phenylenediamine, and 2,5-dimethyl- 1,4-phenylenediamine, 2,5-diethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 4,4'-di Aminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-diethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-diethyl-4 , 4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 4,4 '-Diaminobenzophenone, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,6-diaminopyridine, 3,4-diaminopyridine and the like.

[Synthesis of specific polyaminic acid polymers]

Tetracarboxylic dianhydride and two for the synthesis reaction of a specific poly-proline polymer The ratio of use of the amine compound is preferably such that the acid anhydride group of the tetracarboxylic dianhydride is 0.2 to 2.0 equivalents, more preferably 0.8 to 1.2 equivalents, based on 1 equivalent of the amine group of the diamine compound.

The synthesis reaction of the specific polyaminic acid polymer is carried out usually in an organic solvent at a temperature of from -20 ° C to 150 ° C, preferably from 0 to 100 ° C.

Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized specific polyaminic acid polymer, and specific examples thereof include 1-methyl-2-pyrrolidone and N,N-. Aprotic polar solvents such as dimethylacetamide, N,N-dimethylformamide, dimethyl hydrazine, γ-butyrolactone, tetramethylurea, hexamethylphosphonium triamine; A phenolic solvent such as phenol, xylenol, phenol or halogenated phenol.

Further, the amount (α) of the organic solvent is usually preferably an amount such that the total amount (β) of the tetracarboxylic dianhydride and the diamine compound is from 0.1 to 30% by weight based on the total amount (α + β) of the reaction solution.

Further, in the above organic solvent, alcohols, ketones, and esters which are poor solvents of a specific polyaminic acid polymer may be used in combination insofar as the specific polyamic acid polymer formed is not precipitated. Classes, ethers, halogenated hydrocarbons, hydrocarbons, and the like. Specific examples of such a poor solvent include methanol, ethanol, isopropanol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol, propylene glycol, and 1,4-butane. Alcohol, triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, acetic acid Butyl ester, methyl methoxypropionate, ethyl ethoxy propionate, diethyl oxalate, diethyl malonate, diethyl Ether, ethylene glycol methyl ether, ethylene glycol ethyl 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 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-dichlorobenzene, hexane , heptane, octane, benzene, toluene, xylene, and the like.

As described above, a reaction solution in which a specific polyaminic acid polymer was dissolved was 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, or the reaction solution is distilled off under reduced pressure in an evaporator to obtain a specific polymer polyamine. Further, the specific polyamine can be purified by performing one or several times of dissolving the specific polyaminic acid polymer in an organic solvent, and then precipitating it with a poor solvent, or by distilling off the distillation process with an evaporator. Acid polymer.

[Synthesis of specific polyimine polymers]

The specific polyimine polymer constituting the liquid crystal alignment agent of the present invention can be synthesized by dehydrating a specific poly-proline polymer. The specific polyiminoimine polymer used in the present invention may also be a partially dehydrated ring-closed polymer having a ruthenium iodide ratio of less than 100%. Here, the "rhodium imidization ratio" means a value expressed by a percentage of a repeating unit having a quinone ring or an isoindole ring in all repeating units of the polyimine. The specific polyamidonic acid polymer and/or the specific polyimine polymer used in the present invention preferably has a ruthenium amination ratio of 40% or more. Dehydration ring closure of specific polyaminic acid polymers To use (i) by heating a specific polyaminic acid polymer, or (ii) by dissolving a specific polyaminic acid polymer in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst to the solution, as needed A method of synthesizing by condensation by heating.

In the method of heating the specific polyaminic acid polymer of the above (i), the reaction temperature is preferably from 50 to 200 ° C, more preferably from 60 to 170 ° C. When the reaction temperature is less than 50 ° C, the dehydration ring-closure reaction may not proceed sufficiently. When the reaction temperature exceeds 200 ° C, the molecular weight of the obtained polyimine may decrease.

On the other hand, in the method of adding the dehydrating agent and the dehydration ring-closure catalyst to the specific polyamido acid polymer solution of the above (ii), as the dehydrating agent, an acid anhydride such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride can be used. . The amount of the dehydrating agent is preferably from 0.01 to 20 moles per mole of the repeating unit of the specific mole of the poly-proline polymer. Further, as the dehydration ring-closure catalyst, 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. The higher the amount of the above dehydrating agent and the dehydration ring-closure catalyst, the higher the yield of ruthenium. In addition, examples of the organic solvent used in the dehydration ring-closure reaction include the same organic solvents as those exemplified as the solvent used in the synthesis of the specific polyaminic acid polymer. Further, the reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C, more preferably 10 to 150 ° C. Further, by subjecting the reaction solution thus obtained to the same operation as in the method for purifying a specific polyaminic acid polymer, it is possible to refine a specific polyimine polymerization. Things.

[End modified polymer]

The specific polyaminic acid polymer and the specific polyimine polymer used in the present invention may also be terminal modified polymers having molecular weight adjustment. By using the terminal-modified polymer, the coating characteristics 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 a reaction system at the time of synthesis of a specific polyaminic acid polymer. Here, 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 the like. N-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 isofluoride.

[Polymer viscosity]

The polymer used in the alignment agent of the present invention preferably has a solution of 10% to 800 mPa when formulated into a 10% solution. The viscosity of s is more preferably 30 to 500 mpa. s viscosity.

In addition, the solution viscosity (mPa.s) of the polymer is a prescribed solvent, and the solution having a solid component concentration diluted to 10% is an E-type rotational viscometer. Measured at 25 ° C.

[Polylination rate of polymer]

The specific polyiminoimine polymer obtained as above has a ruthenium imidation ratio of preferably 40% or more from the viewpoint of improving voltage holding performance.

The value of the oxime imidization ratio of the specific polyimine polymer used in the present invention is that the polyimine is dried under reduced pressure at room temperature and then dissolved in deuterated dimethyl hydrazine to Tetramethyl decane was used as a reference, and ¹ H-NMR was measured at room temperature, and the value was obtained by the formula represented by the following formula (i).

Formula (i): oxime imidization ratio (%) = (1-A ¹ /A ² × α ) × 100

Here, A1 is the peak area (10 ppm) derived from the NH proton, A2 is the peak area derived from the aromatic ring proton (7 to 8 ppm), and α is relative to the polymer precursor (specific poly-proline polymer) The ratio of the number of protons derived from the aromatic ring of one NH matrix.

[Liquid alignment agent]

The liquid crystal alignment agent of the present invention is constituted by dissolving the above specific polyaminic acid polymer and/or a specific polyimine polymer in a mixed solvent. Here, the temperature at which the liquid crystal alignment agent is prepared is preferably 0 ° C to 200 ° C, more preferably 20 ° C to 60 ° C.

The mixed solvent used in the liquid crystal alignment agent of the present invention comprises: selected from the group consisting of N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, N,N- a solvent A composed of at least one of dimethylformamide and N,N-dimethylacetamide; selected from the group consisting of butyl sirolimus, diacetone alcohol, propylene carbonate, diethylene glycol diethyl ether And at least one of ethyl 3-ethoxypropionate Solvent B; and solvent C composed of at least one selected from the group consisting of compounds represented by the above formula (III).

The solvent C preferably has a boiling point of 140 to 190 ° C from the viewpoint of uniformity of the drying speed of the liquid.

In addition, as the solvent C, it is preferable to satisfy any of the following conditions (1) to (3) from the viewpoint of liquid expandability of the obtained liquid crystal alignment agent.

(1) A solvent composed of a compound in which Z is -O- in the formula (III) and a carbon number of R ³ and R ⁴ is 6 to 10 in total, and particularly preferably a surface tension of 25 mN/m or less.

(2) A solvent composed of a compound in which Z in the formula (III) is -CO- and the carbon number of R ³ and R ⁴ is 8 in total, particularly preferably a surface tension of 24 mN/m or less.

(3) A solvent composed of a compound of the formula (III) wherein Z is -COO- and the carbon number of R ³ and R ⁴ is 6 to 9 in total, particularly preferably a surface tension of 26 mN/m or less.

Specific examples of the solvent of the above (1) include di-n-pentyl ether and di-n-butyl ether.

Specific examples of the solvent of the above (2) include 2-nonanone, 3-fluorenone, 4-fluorenone, 5-fluorenone, 5-methyl-2-octanone, and 2-methyl-4. - Octanone, 2,4-dimethyl-3-heptanone, 1-cyclohexyl-1-propanone, and the like.

Specific examples of the solvent of the above (3) include n-hexyl acetate, 2-ethylbutyl acetate, n-butyl propionate, n-amyl acetate, n-butyl acetate, and the like.

The content ratio of the solvent A in the mixed solvent is preferably from 40 to 80% by weight, more preferably from 45 to 70% by weight.

The content ratio of the solvent B in the mixed solvent is preferably from 10 to 50% by weight, more preferably from 20 to 50% by weight.

The content ratio of the solvent C in the mixed solvent is preferably from 0.1 to 30% by weight, more preferably from 1 to 20% by weight.

Further, as the mixed solvent, it is preferred that the liquid crystal alignment agent does not precipitate a polymer and the surface tension of the liquid crystal alignment agent is in the range of 25 to 40 mN/m.

In the mixed solvent, a solvent other than the solvent A, the solvent B, and the solvent C (hereinafter referred to as "another solvent") may be contained within a range not impairing the effects of the present invention.

Specific examples of such other solvents include γ-butyrolactam, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, and methoxypropionic acid. Methyl ester, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol propyl ether, ethylene glycol isopropyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate Ester, diethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, and the like.

The 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. That is, the liquid crystal alignment agent of the present invention is applied to the surface of the substrate to form a resin film as a liquid crystal alignment film, and when the solid content concentration is less than 1% by weight, the result is The thickness of the resin film is too small to obtain a good liquid crystal alignment film; when the solid content concentration exceeds 10% by weight, the thickness of the resin film is too thick, so that a good liquid crystal alignment film cannot be obtained, and the viscosity of the liquid crystal alignment agent is not obtained. The increase causes the coating properties to deteriorate. Further, a particularly preferable solid content concentration range differs depending on the method used when the liquid crystal alignment agent is applied to the substrate. For example, when the spin coating method is employed, it is particularly preferably in the range of 1.5 to 4.5% by weight. When using the printing method, it is particularly preferable to make the solid content concentration range of 4 to 10% by weight, so that the solution viscosity can be reduced to 10 to 50 mPa. The scope of s. When the inkjet method is used, it is particularly preferable to make the solid content concentration in the range of 2 to 5% by weight, so that the solution viscosity can be reduced to 5 to 15 mPa. The scope of s.

The liquid crystal alignment agent of the present invention may further contain an epoxy group-based compound, and specific examples thereof include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and the like. Propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromo neopentyl glycol Diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N',N'-tetraglycidyl-p-phenylenediamine, N,N, N',N'-tetraglycidyl-m-phenylenediamine, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N' , N'-tetraglycidyl-4,4'-diaminodiphenyl ether, N,N,N',N'-tetraglycidyl-2,2'-dimethyl-4,4' -diaminobiphenyl, N,N,N',N'-tetraglycidyl-1,2-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1, 3-diaminocyclohexane, N,N,N',N'- Tetraglycidyl-1,4-diaminocyclohexane, bis(N,N-diglycidyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-2-methyl) 4-aminocyclohexyl)methane, bis(N,N-diglycidyl-3-methyl-4-aminocyclohexyl)methane, 1,3-bis(N,N-diglycidyl) Aminomethyl)cyclohexane, 1,4-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl) Benzene, 1,4-bis(N,N-diglycidylaminomethyl)benzene, 1,3,5-tris(N,N-diglycidylaminomethyl)cyclohexane, 1 3,5-tris(N,N-diglycidylaminomethyl)benzene, a compound represented by the following formulas (31) to (35), and the like.

Further, in the liquid crystal alignment agent of the present invention, a compound containing a functional decane may be contained from the viewpoint of improving the adhesion to the surface of the substrate within a range not impairing the physical properties of the object. As such a functional decane-containing compound, for example, 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 2-aminopropyltrimethoxydecane, 2- Aminopropyltriethoxydecane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyl Dimethoxyoxane, 3-ureidopropyltrimethoxydecane, 3-ureidopropyltriethoxydecane, N-ethoxycarbonyl-3-aminopropyltrimethoxydecane, N-B Oxycarbo-3-aminopropyl Triethoxy decane, N-triethoxydecylpropyltriethylamine, N-trimethoxydecylpropyltriethylamine, 10-trimethoxydecyl-1 4,7-triazadecane, 10-triethoxydecyl-1,4,7-triazadecane, 9-trimethoxydecyl-3,6-diazepineacetic acid Ester, 9-triethoxydecyl-3,6-diazaindolyl acetate, N-benzyl-3-aminopropyltrimethoxydecane, N-benzyl-3-aminopropyl Triethoxy decane, N-phenyl-3-aminopropyltrimethoxydecane, N-phenyl-3-aminopropyltriethoxydecane, N-bis(oxyvinyl)-3 -Aminopropyltrimethoxydecane, N-bis(oxyvinyl)-3-aminopropyltriethoxydecane, 3-(N-allyl-N-glycidyl)aminopropyl Trimethoxy decane, 3-(N,N-diglycidyl)aminopropyltrimethoxydecane, and the like.

[Manufacture of display elements using liquid crystal alignment agents]

The liquid crystal display element using the vertical alignment type 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 provided with a patterned transparent conductive film by, for example, a roll coating method, a spin coating method, a printing method, an inkjet method, or the like, followed by heat coating. The coated surface forms a coating film. Here, as the substrate, for example, glass such as float glass or soda lime glass can be used; and it is composed of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether oxime or polycarbonate. Transparent substrate. 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) and made of indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) can be used. ITO film, etc. These transparent conductive film patterns are formed by photolithography or 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 surface of the substrate and the resin film, for example, a compound containing a functional decane, a compound containing a functional titanium, or the like may be applied in advance. The heating temperature after the application of the liquid crystal alignment agent is preferably from 80 to 300 ° C or more preferably from 120 to 250 ° C. Further, the liquid crystal alignment agent of the present invention removes an organic solvent by coating to form a resin film as an alignment film, and when it has not been completely imidized, it can be further subjected to dehydration ring closure by heating to form further yam. Aminated resin film. The thickness of the formed resin film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.

(2) Two substrates on which the vertical liquid crystal alignment film is formed are formed, and the two substrates are opposed to each other through a gap (cell gap), and the peripheral portions of the two substrates are bonded together with a sealant, and are separated from the surface of the substrate and the sealant. The liquid crystal gap is injected into the cell gap to close the injection hole to form a liquid crystal cell. Then, a polarizing plate is disposed on the outer surface of the liquid crystal cell, that is, on the transparent substrate side constituting the liquid crystal cell, to obtain a liquid crystal display element.

Here, as the sealant, for example, an alumina ball-containing epoxy resin or the like as a curing agent and a spacer may 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, and for example, a Schiff base liquid crystal, an oxidized azo liquid crystal, a biphenyl liquid crystal, or a phenyl ring can be used. Hexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, two An alkane liquid crystal, a bicyclooctane liquid crystal, a cubic liquid crystal, or the like. Further, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl phthalate, and cholesteryl carbonate may be added to these liquid crystals, and trade names "C-15" and "CB-15" (manufactured by Merck) may be added. It is used by selling chiral agents and the like. Further, a ferroelectric liquid crystal such as p-methoxybenzylidene-p-amino-2-methylbutylcinnamate may also be used.

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

[Examples]

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

Further, various measurements of the examples and comparative examples were carried out in the following manner.

(1) Vertical alignment evaluation When the vertical alignment type liquid crystal display element produced by the above method was subjected to visual observation of the liquid crystal display element from the vertical direction when no voltage was applied under crossed polarography (Cross Nicol), it was evaluated as "good" when no light leakage was observed.

(2) Voltage retention rate A voltage of 5 V was applied to the liquid crystal display element at 60 ° C for a time span of 16.7 μs, the voltage application time was 60 μsec, and then the voltage holding ratio from the voltage release to 16.7 msec was measured.

(3) Printability evaluation The modulation viscosity is 15~25mPa. s (solid content concentration is 6.0% by weight ~8.0% by weight), the solvent composition was a solution having the compositions shown in Tables 2 and 3 below. It was applied to a transparent electrode surface of a glass substrate with a transparent electrode in which a strip-shaped ITO film having a thickness of 200 nm and a width of 20 μm was formed at intervals of 100 μm by a liquid crystal alignment agent (manufactured by Japan Photo Printing Co., Ltd.). . After the coated substrate was allowed to stand for 1 minute and formed into a liquid crystal alignment film by baking, the peripheral portion and the central portion of the liquid crystal alignment film were observed under a microscope at a magnification of 10 times, and no unevenness or repulsion was judged as "good". The determination of uneven coating or cracking is "poor".

(4) The ruthenium imine rate of the ruthenium iodide polymer

The ruthenium iodide polymer was dried under reduced pressure at room temperature, and then dissolved in deuterated dimethyl hydrazine, and ¹ H-NMR was measured at room temperature using tetramethyl decane as a reference. The formula shown in the formula (i) is obtained.

醯 imidization rate (%) = (1-A ¹ /A ² × α ) × 100 (i)

A ¹ : Peak area derived from NH proton (10 ppm)

A ² : peak area of protons derived from aromatic rings (7 to 8 ppm)

α : The ratio of the number of protons derived from the aromatic ring to the precursor of one polymer (polyproline) relative to one NH matrix.

(5) Solution viscosity of the polymer

The solution viscosity (mPa.s) of the polymer was measured by using a predetermined solvent, and the solution having a solid content concentration of 10% by weight was measured at 25 ° C using an E-type rotational viscometer.

(Synthesis examples 16 to 21)

According to the composition shown in Table 1, according to the N-methyl-2-pyrrolidone A diamine compound and a tetracarboxylic dianhydride (indicated as "anhydride" in the table) were added, and a solution having a solid concentration of 20% by weight was prepared, and reacted at 60 ° C for 4 hours to obtain the results shown in Table 1. Polylysine polymer solution (PA-1) ~ (PA-6). These polyaminic acid solutions were each taken in small amounts, diluted with N-methyl-2-pyrrolidone to a solid concentration of 10% by weight, and the solution viscosity was measured. The measured values of the solution viscosity are listed in Table 1.

(Synthesis Examples 1 to 15)

According to the composition shown in Table 1, a diamine compound and a tetracarboxylic dianhydride (indicated as "anhydride" in the table) were added to N-methyl-2-pyrrolidone in the order, and the solid concentration was 20 The % by weight solution was allowed to react at 60 ° C for 4 hours to obtain a polyaminic acid polymer solution. The obtained polyaminic acid polymer solution was diluted to 2 times with N-methyl-2-pyrrolidone, and further, after adding the molar ratio of pyridine and acetic anhydride shown in Table 1, to the repeating unit of the poly-proline polymer, It was heated at 110 ° C for 4 hours to dehydrate the ring. After the ruthenium imidization reaction, the solvent in the system is subjected to solvent replacement with a new NMP (by this operation, the pyridine and acetic anhydride used in the oxime imidization reaction are excluded from the system) to obtain a solid concentration of about 15 % by weight of polyamidene polymer solution (PI-1) ~ (PI-15). The viscosity and oxime imidization ratio of the N-methyl-2-pyrrolidone solution (10% by weight) of these polyimine polymers are shown in Table 1.

In the diamine compound and the acid anhydride in Table 1, the numbers in parentheses indicate the content ratio, and the symbols in Table 1 have the following meanings.

<Diamine compound>

D-1: a diamine compound represented by the above formula (10)

D-2: a diamine compound represented by the above formula (11)

D-3: a diamine compound represented by the above formula (13)

D-4: a diamine compound represented by the above formula (21)

D-5: p-phenylenediamine

D-6: 4,4'-diaminodiphenylmethane

D-7: 4,4'-diaminodiphenyl ether

D-8: 2,2'-dimethyl-4,4'-diaminobiphenyl

<tetracarboxylic dianhydride>

T-1:1,2,4,5-cyclohexanetetracarboxylic dianhydride

T-2: 2,3,5-tricarboxycyclopentyl acetic acid dianhydride

T-3: 1,2,3,4-cyclobutane tetracarboxylic dianhydride

T-4: 1,3,3a,4,5,9b-hexahydro-8-methyl-5(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene [1,2-c ]-furan-1,3-dione

T-5: pyromellitic dianhydride

(Example 1)

The polymer solution (PI-1) prepared in Synthesis Example 1 was dissolved in a mixed solvent of N-methyl-2-pyrrolidone/butyl races/n-hexyl acetate to prepare a solvent composition (N- A solution of methyl-2-pyrrolidone/butyl sarbuta/n-hexyl acetate = 50/40/10: weight ratio) and a solid concentration of 6 wt%. Then, the liquid crystal alignment agent of the present invention was obtained by filtration using a filter having a pore size of 0.2 μm. The liquid crystal alignment agent was evaluated for printability, and no film was applied. It is now rejected or unevenly coated, and it is confirmed that it has good printability.

Then, the liquid crystal alignment agent of the present invention was prepared in the same manner as above except that the solid content concentration was 4% by weight.

The obtained liquid crystal alignment agent was applied by spin coating to a transparent conductive film made of ITO provided on one surface of a glass substrate having a thickness of 1 mm, and dried at 200 ° C for 60 minutes to form a dried film thickness of 0.08 μm. Laminating.

In this way, two substrates for liquid crystal display elements are produced, and an epoxy resin adhesive containing alumina balls having a diameter of 3.5 μm is applied to the outer edge portions of the liquid crystal alignment film forming surfaces of the liquid crystal display element substrates, and then passed through a liquid crystal. The alignment films are recombined and pressed against each other to form a gap, and the adhesive is hardened in this state.

Then, a negative liquid crystal (MLC-6608, manufactured by Merck & Co., Inc.) is filled in the cell gap between the liquid crystal display elements and the liquid crystal display port, and the injection port is closed with an acrylic photo-curing adhesive. A polarizing plate was bonded to both sides of the outer surface of the display element substrate to fabricate a liquid crystal display element.

The vertical alignment property evaluation of the obtained liquid crystal display element was good. Further, the voltage holding ratio was measured to be 99% or more, and it was confirmed that the liquid crystal display element was extremely excellent.

(Examples 2 to 28, Comparative Examples 1 to 3)

A solution having a solid concentration of 6% was prepared in the same manner as in Example 1 in accordance with the following Table 2 and the formulation shown in the following Table 3 to obtain a liquid crystal alignment agent, and the solubility and printability of the liquid crystal alignment agent were evaluated. Further, a solution having a solid concentration of 4% was prepared in the same manner to prepare a liquid crystal display element. then. The vertical alignment evaluation was performed and the voltage holding ratio was measured. The results are shown in Tables 2 and 3.

In the polymers of Examples 21 to 28 in Table 2, the mixing ratio of both polymers was 50/50 (% by weight).

In addition, the solvents shown in Table 2 and Table 3 are as follows.

<solvent>

A-1: γ-butyrolactone

A-2: N-methyl-2-pyrrolidone

A-3: 1,3-dimethyl-2-imidazolidinone

B-1: Butyl Cyrus

B-2: Diacetone alcohol

B-3: propylene carbonate B-4: diethylene glycol diethyl ether C-1: n-hexyl acetate C-2: n-pentyl acetate C-3: 5-anthrone C-4: 5-methyl -2-octanone C-5: 2,4-dimethyl-3-heptanone

From the above results, it was confirmed that the liquid crystal alignment agent of the present invention has excellent printability and can form a liquid crystal alignment film having excellent vertical alignment properties and high voltage holding ratio.

Claims (6)

A vertical alignment type liquid crystal alignment agent comprising: a polymer comprising at least one group consisting of repeating units each represented by the following formula (I-1) and the following formula (I-2) a repeating unit selected from the group consisting of at least one of the divalent organic groups represented by the following formula (II-1) and formula (II-2) as Q ¹ in the following formula (I-1) And Q ² in the following formula (I-2); and a mixed solvent comprising: selected from the group consisting of N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl a solvent A composed of at least one of 2-imidazolidinone, N,N-dimethylformamide and N,N-dimethylacetamide; selected from the group consisting of butyl sirolimus and diacetone alcohol a solvent B composed of at least one of propylene carbonate, diethylene glycol diethyl ether and ethyl 3-ethoxypropionate; and at least one selected from the group consisting of compounds represented by the following formula (III) The solvent C formed; (In the formula (I-1), P ¹ is a tetravalent organic group derived from a tetracarboxylic acid, and Q ¹ is a divalent organic group derived from a diamine compound; further, in the formula (I-2), P ² is a tetravalent organic group derived from a tetracarboxylic acid, and Q ² is a divalent organic group derived from a diamine compound) (In the formula (II-1), X ¹ is a single bond, -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH-, -S-, methylene, and the carbon number is 2 to 6 alkyl or phenyl, R ¹ is an alkyl group having 10 to 20 carbon atoms, a monovalent organic group having an alicyclic skeleton having a carbon number of 4 to 40, or a carbon number of 6 to 20 a monovalent organic group of a fluorine atom; in addition, in the formula (II-2), X ¹ is a single bond, -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH- , -S-, methylene, an alkyl group having a carbon number of 2 to 6 or a phenyl group, and R ² is a divalent organic group having an alicyclic skeleton having a carbon number of 4 to 40 or a carbon number of 5 ~30 of a fluorine atom-containing divalent organic group), (In the formula (III), Z is -O-, -CO- or -COO-, and R ³ and R ⁴ are each a monovalent hydrocarbon group, and the carbon numbers of R ³ and R ⁴ are 6 to 10 in total. The vertical alignment type liquid crystal alignment agent of claim 1, wherein the solvent C has a boiling point of 140 ° C or higher. The vertical alignment type liquid crystal alignment agent according to claim 1 or 2, wherein the solvent C satisfies any of the following conditions (1) to (3), and (1) in the formula (III), Z is -O- And the total number of carbon atoms of R ³ and R ⁴ is 6 to 10; (2) the compound of the formula (III) wherein Z is -CO- and the carbon number of R ³ and R ⁴ is 8 in total; (3) III) A compound wherein Z is -COO- and the carbon numbers of R ³ and R ⁴ are 6 to 9 in total. The vertical alignment type liquid crystal alignment agent according to claim 1 or 2, wherein the solvent C satisfies any of the following conditions (4) to (6), and (4) the formula (III) wherein Z is -O- And R ³ and R ^{4 have} a total carbon number of 6 to 10, and the surface tension thereof is 25 mN/m or less; (5) in the formula (III), Z is -CO- and the total carbon number of R ³ and R ⁴ is a compound of 8 having a surface tension of 24 mN/m or less; (6) a compound of the formula (III) wherein Z is -COO- and R ³ and R ^{4 have} a carbon number of 6 to 9 in total, and the surface tension is 26 mN/m. the following. The vertical alignment type liquid crystal alignment agent according to claim 1 or 2, wherein the content ratio of the solvent C in the mixed solvent is 0.1 to 40% by weight. A liquid crystal display element characterized by having a vertical alignment type liquid crystal alignment film produced by the vertical alignment type liquid crystal alignment agent according to any one of claims 1 to 5.