KR20020063829A - Vertical Alignment Film of Liquid Crystal, Liquid Crystal Alignment Agent and Liquid Crystal Display Device with Vertical Alignment Type - Google Patents

Abstract

The present invention provides a vertical liquid crystal alignment film excellent in vertical liquid crystal alignment and voltage holding characteristics.

This is a vertically aligned liquid crystal alignment film obtained by irradiating a film having a surface tension of 40 dyn / cm or less with unpolarized ultraviolet light at an irradiation angle of less than 90 degrees.

Description

Vertical alignment film of liquid crystal, liquid crystal alignment agent and liquid crystal display device with vertical alignment type

The present invention relates to a vertical alignment liquid crystal alignment film and a vertical alignment liquid crystal display element. More specifically, it relates to the liquid crystal aligning film and the vertical liquid crystal display element which were excellent in the perpendicular | vertical liquid crystal orientation by voltage | radiation irradiation of unpolarized ultraviolet-ray, voltage retention characteristic.

At present, as a liquid crystal display element, the liquid crystal aligning film containing polyamic acid, polyimide, etc. is formed in the surface of the board | substrate with which a transparent conductive film is provided, and it is set as a board | substrate for liquid crystal display elements, and it arrange | positions two sheets and opposes positive dielectric anisotropy in the clearance gap. A TN type liquid crystal display device having a TN type (Twisted Nematic) liquid crystal cell configured to form a nematic liquid crystal layer having a sandwich cell, and have a long axis of liquid crystal molecules twisted 90 degrees continuously from one substrate to the other substrate. Known. Moreover, STN (Super Twisted Nematic) type | mold liquid crystal display element and a vertically oriented liquid crystal display element which have a high contrast compared with TN type liquid crystal display element, and its visual dependence are being developed. The STN type liquid crystal display element uses what blended the chiral agent which is an optically active substance with a nematic liquid crystal as a liquid crystal, and uses the birefringence effect which arises when the long axis of a liquid crystal molecule twists continuously more than 180 degrees between board | substrates. Such a liquid crystal display element was obtained by orienting an alignment film by the rubbing method. However, since the rubbing method rubs the alignment film with a cloth, dust and static electricity are generated to lower the yield, or require a cleaning step after rubbing, and the productivity is not high. In addition, the demand for wide viewing angle has increased and it has been necessary to divide the orientation. The mask rubbing method is known as a method of orientation division, but there are disadvantages such as a complicated process and poor productivity.

On the other hand, the optical alignment has the advantage that the orientation can be easily divided by the mask, the productivity is excellent, and the wide viewing angle is easy. However, in order to obtain the same degree of liquid crystal alignment as rubbing, it is necessary to irradiate a considerable amount of light, thereby adversely affecting the electrical properties since the decomposition reaction of the alignment film proceeds. In addition, although deflected light is conventionally used, a considerable amount of light is absorbed by the polarizing plate when passing through the polarizing plate, and the utilization efficiency of the light is poor.

In order to improve this, a method of vertically aligning liquid crystals by obliquely irradiating unpolarized ultraviolet rays has been developed.

An object of the present invention is to provide a vertical alignment liquid crystal alignment film. Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are achieved by a vertical liquid crystal alignment film obtained by irradiating a film having a surface tension of 40 dyn / cm or less with unpolarized ultraviolet light at an irradiation angle of less than 90 degrees.

Hereinafter, the present invention will be described in detail.

As a polymer which comprises the thin film whose surface tension is 40 dyn / cm or less used by this invention, a polyamic acid, a polyimide, an alkoxysilane hydrolysis-condensation product, a polyacrylate, etc. are mentioned. Of these, polyamic acid and polyimide are preferred. Among these, polymers having a repeating unit represented by the following general formula (1a) and / or a repeating unit represented by the following general formula (1b) (hereinafter, these are referred to as "specific repeating units") (hereinafter referred to as "specific polymers") are preferable. . It is preferable that the ratio of a specific repeating unit in a specific polymer is 10 mol% or more of all the repeating units.

In formula, A <^1> is a tetravalent organic group and B <^1> is group represented by following formula (2a) or (2b).

In the formula, A ² is a tetravalent organic group, and B ² is a group represented by the following formula (2a) or (2b).

Wherein X is a divalent group selected from -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH- and -S-, and R ¹ is a hydrocarbon group having 12 to 30 carbon atoms Or a monovalent organic group which is a C6 or more fluorine-containing hydrocarbon group.

Wherein X is a divalent group selected from -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH- and -S-, and R ² is a hydrocarbon group having 12 to 30 carbon atoms Or a divalent organic group that is a fluorine-containing hydrocarbon group having 6 or more carbon atoms.

As said specific polymer, the imidation polymer which has a polyamic acid and the structure obtained by dehydrating and ring-closing this polyamic acid is mentioned.

The polyamic acid preferably used in the present invention can be obtained by subjecting tetracarboxylic dianhydride and one or more diamines (hereinafter, referred to as "specific diamines") selected from the following formulas 3a and 3b to ring-opening polyaddition. The imidized polymer preferably used in the invention can be obtained by dehydrating and closing the polyamic acid.

It is preferable to use the polyamic acid and imidation polymer used by this invention which has an alicyclic skeleton in 1 or more parts of tetracarboxylic dianhydride.

[Polyamic acid]

Tetracarboxylic dianhydride

As tetracarboxylic dianhydride which can be used for the synthesis | combination of the said polyamic acid, For example, aliphatic tetracarboxylic dianhydrides, such as butane tetracarboxylic dianhydride; 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2, 3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2 , 3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3, 3 ', 4,4'-dicyclohexyltetracarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6- dianhydride, 2,3,4,5- Tetrahydrofurantetetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2- c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1 , 3,3a, 4,5,9b-hexahydro-5-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1, 3-dione, 1,3,3a, 4,5,9b-hexahydro-7-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] Furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1 , 2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) Naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-ethyl-5 (tetrahydro-2,5-dioxo- 3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5,8-dimethyl-5 (tetrahydro- 2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -3-methyl-3 -Cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2.2.2] -octo-7-ene-2, Aliphatic tetracarboxylic dianhydrides such as 3,5,6-tetracarboxylic dianhydride and compounds represented by the following formulas (4) and (5);

Pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylsulfontetracarboxylic dianhydride, 1,4,5 , 8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenylethertetracarboxylic dianhydride, 3,3 ', 4,4'-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3', 4,4'-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic Acid dianhydrides, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfide dianhydrides, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydrides, 4 , 4'-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ', 4,4'-perfluoroisopropylidenediphthalic dianhydride, 3,3', 4,4 '-Biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride , m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4'-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4'-diphenylmethane dianhydride , Ethylene glycol -bis (anhydrotrimelitate), propylene glycol -bis (anhydrotrimelitate), 1,4-butanediol-bis (anhydrotrimelitate), 1,6-hexanediol-bis (an Hydrotrimellitate), 1,8-octanediol-bis (anhydrotrimelitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimelitate), the following formulas 6 to 9 Aromatic tetracarboxylic dianhydrides, such as a compound represented by these, are mentioned. These are used individually by 1 type or in combination of 2 or more types.

In the formula, R ³ and R ⁵ represent a divalent organic group having an aromatic ring, R ⁴ and R ⁶ represent a hydrogen atom or an alkyl group, and a plurality of R ⁴ and R ^{6 present} may be the same or different.

In these, 50 mol% or more is alicyclic tetracarboxylic dianhydride from a viewpoint of voltage retention. Preferred alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5- (2,5-dioxotetrahydrofuranyl) -3-methyl- 3-cyclohexene-1,2-dicarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride, 3, 5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5 -Dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetra Hydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5,8 -Dimethyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, bicyclo [2.2.2 ] -Octo-7-ene-2,3,5,6-tetracarboxylic dianhydride,

Among the compounds represented by Formula 4, compounds represented by the following Formulas 10 to 12 and compounds represented by Formula 5 may include compounds represented by Formula 13 below. Preferred tetracarboxylic dianhydrides other than alicyclic are butanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenylsulfontetracarboxylic dianhydride and 1,4,5,8-naphthalenetetracarboxylic dianhydride are preferable because they can express good liquid crystal orientation. Especially preferred are 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5- Tricarboxycyclopentylacetic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c ] Furan-1,3-dione, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride, 3,5,6-tricarbonyl 2-carboxynorbornane-2: 3,5: 6-dianhydride, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo 3-furanyl) -naphtho [1,2-c] furan-1,3-dione, a pyromellitic dianhydride, and the compound represented by following formula (10) are mentioned.

[Diamine Compound]

Examples of the monovalent organic group which is a hydrocarbon group having 12 to 30 carbon atoms in Chemical Formula 3a include, for example, a straight chain such as n-dodecyl group, n-pentadecyl group, n-hexadecyl group, n-octadecyl group, n-ecosyl group, or the like. Branched alkyl groups; Alicyclic hydrocarbon groups such as bicyclohexyl group, cyclododecyl group, and adamantyl group: aromatic hydrocarbon groups such as biphenyl group, naphthyl group and anthryl group; Steroid skeletons, such as a cholesteryl group and a cholesteryl group, etc. are mentioned.

Moreover, as monovalent organic group which is a C6 or more fluorine-containing hydrocarbon group, For example, C6-C11 linear alkyl groups, such as n-hexyl group, n-octyl group, n-decyl group; Alicyclic hydrocarbon groups having 6 to 11 carbon atoms such as a cyclohexyl group, a cyclopentyl group, and a cyclooctyl group; The group in which one part or all of the hydrogen atoms were substituted by the fluorine atom or the fluoroalkyl group in organic groups, such as a C6-C11 aromatic hydrocarbon group, such as a phenyl group, is mentioned.

As said divalent organic group which is a C12-C30 hydrocarbon group and a bivalent organic group which is a C6 or more fluorine-containing hydrocarbon group in said Formula (3b), the bivalent organic group except the one hydrogen atom from the said monovalent organic group which is a C12-C30 hydrocarbon group Organic groups may be mentioned.

As a specific example of the specific diamine represented by the said Formula (3a), for example, dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diamino Benzene, octadecanoxy-2,4-diaminobenzene, dodecanoxy-2,5-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-dia Minobenzene, an octadecanoxy-2, 5- diamino benzene, the compound represented by following formula (14) -21 is mentioned. These diamine compounds may be used alone or in combination of two or more thereof.

Moreover, as a specific example of the specific diamine represented by the said General formula (3b), the compound represented by following formula (22)-25 is mentioned, for example. These diamine compounds can be used individually or in combination of 2 or more types.

In the formula, R is an alkylene group having 12 to 30 carbon atoms, and y is an integer of 2 to 12.

Other diamine may be used together with the specific polymer used by this invention in the range which does not impair the effect of this invention. Examples of other diamines include p-phenylenediamine, m-phenylenediamine, 1,1-methaxylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4 , 4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 4 , 4'-diaminodiphenylether, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl) -1, 3,3-trimethylindane, 6-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 3,4'-diaminodiphenylether, 3,3'-diaminobenzophenone , 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4 -Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4 -Bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy ) Benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, 2,7-diaminofluorene, 9,9-bis (4 -Aminophenyl) fluorene, 4,4'-methylene-bis (2-chloroaniline), 2,2 ', 5,5'-tetrachloro-4,4'-diaminobiphenyl, 2,2'- Dichloro-4,4'-diamino-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 1,4,4 '-(p-phenylene Isopropylidene) bisaniline, 4,4 '-(m-phenyleneisopropylidene) bisaniline, 2,2'-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexa Fluoropropane, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl, 4,4'-bis [(4-amino-2-trifluoromethyl) phenoxy]- Aromatic diamines such as octafluorobiphenyl;

Aliphatic diamines such as 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, and 4,4-diaminoheptamethylenediamine;

1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindenylenedimethylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenedimethyl Alicyclic diamines such as diamine and 4,4'-methylenebis (cyclohexylamine);

2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5, 6-diamino-2,4-dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino- 6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl-s-triazine, 2,4-diamino-1,3,5-triazine, 4,6-dia Mino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6-diaminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5- Diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6-phenylphenanthtridine, 1,4-diaminopiperazine, Two molecules in a molecule such as 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine, and the compounds represented by the following formulas 26 and 27 Diamines having a nitrogen atom other than the primary amino group and the primary amino group;

In the formula, R ⁷ represents a monovalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, and Y represents a divalent organic group.

In the formula, R ⁸ represents a divalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, Y represents a divalent organic group, and a plurality of Y May be the same or different.

And diamino organosiloxane represented by the following formula (28).

In formula, R <^9> represents a C1-C12 hydrocarbon group, two or more R <^9> may be same or different, p is an integer of 1-3, q is an integer of 1-20.

These diamine compounds can be used individually or in combination of 2 or more types.

Among them, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4 , 4'-diaminodiphenylether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4 -(4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '-(p-phenylenediisopropylidene) bisaniline, 4, 4 '-(m-phenylenediisopropylidene) bisaniline, 1,4-cyclohexanediamine, 4,4'-methylenebis (cyclohexylamine), 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, And among the compounds represented by the following Chemical Formula 26, the compound represented by the following Chemical Formula 29, and the compound represented by the following Chemical Formula 27, by The compound represented is preferable.

The usage-amount of specific diamine is 10 mol% or more normally in all diamine, Preferably it is 10-50 mol%. When the usage-amount of specific diamine is less than 10 mol%, sufficient perpendicular orientation may not be obtained.

Synthesis of Polyamic Acid

As for the usage ratio of the tetracarboxylic dianhydride and diamine provided for a polyamic-acid synthesis reaction, the ratio in which the acid anhydride group of tetracarboxylic dianhydride becomes 0.2-2 equivalent with respect to 1 equivalent of amino group of diamine is more preferable. Is a ratio of 0.3 to 1.2 equivalents.

It is preferable that the polyamic acid used by this invention has an alicyclic skeleton, and what was obtained using what has an alicyclic skeleton in tetracarboxylic dianhydride and / or diamine is preferable. Among them, more preferred is to use tetracarboxylic dianhydride having an alicyclic skeleton.

The synthesis reaction of the polyamic acid is preferably carried out in an organic solvent under temperature conditions of -20 ° C to 150 ° C, more preferably 0 to 100 ° C. The organic solvent is not particularly limited as long as it can dissolve the polyamic acid synthesized, and examples thereof include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, and dimethyl. Aprotic polar solvents such as sulfoxide, γ-butyrolactone, tetramethyl urea and hexamethylphospholtriamide; and phenol solvents such as m-cresol, xylenol, phenol, and halogenated phenol. In addition, it is preferable that the usage-amount ((alpha)) of an organic solvent shall be 0.1-30 weight% with respect to the total amount ((beta)) of tetracarboxylic dianhydride and a diamine compound with respect to the reaction solution total amount ((alpha) + (beta)).

In the organic solvent, alcohols, ketones, esters, ethers, halogenated hydrocarbons or hydrocarbons, which are poor solvents of the polyamic acid, can be used in combination within the range in which the resulting polyamic acid is not precipitated. . As a specific example of such a poor solvent, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol, propylene glycol, 1,4-butanediol, Triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxy propionate, ethyl ethoxy Propionate, diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether , Ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol Col monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloro Roethane, chlorbenzene, o-dichlorbenzene, hexane, heptane, octane, benzene, toluene, xylene and the like.

The reaction solution which melt | dissolves a polyamic acid as mentioned above can be obtained. The reaction solution is poured into a large amount of poor solvent to obtain a precipitate, and the polyamic acid can be obtained by drying the precipitate under reduced pressure. In addition, the polyamic acid can be purified by dissolving the polyamic acid again in an organic solvent and then precipitating with a poor solvent once or several times.

[Synthesis of imidized polymer]

The imidation polymer which comprises the liquid crystal aligning agent of this invention can be synthesize | combined by dehydrating and ring-closing the said polyamic acid. The dehydration ring closure of the polyamic acid may be carried out by (i) a method of heating the polyamic acid, or (ii) by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating it as necessary. Is done. In addition, the imidation polymer used by this invention has the imidation ratio (the ratio of the imide ring repeating unit to% total number of the amic acid repeating unit and the imide ring repeating unit in a polymer) partially dehydrated and closed. Imidized polymers of less than 100% may be included.

The reaction temperature in the method of heating the polyamic acid of said (i) becomes like this. Preferably it is 50-200 degreeC, More preferably, it is 60-170 degreeC. When reaction temperature is less than 50 degreeC, dehydration ring-closure reaction does not fully advance, and when reaction temperature exceeds 200 degreeC, the molecular weight of the imidation polymer obtained may fall.

On the other hand, in the method of adding a dehydrating agent and a dehydration ring-closure catalyst to the polyamic acid solution of said (ii), acid anhydrides, such as an acetic anhydride, a propionic anhydride, a trifluoroacetic anhydride, can be used as a dehydrating agent, for example. Although the usage-amount of a dehydrating agent changes with a desired imidation ratio, it is preferable to set it as 0.01-20 mol with respect to 1 mol of polyamic-acid repeating units. As the dehydration ring closure catalyst, tertiary amines such as pyridine, collidine, lutidine and triethylamine can be used, for example. However, it is not limited to these. It is preferable that the usage-amount of a dehydration ring-closure catalyst shall be 0.01-10 mol with respect to 1 mol of dehydrating agents used. The imidation ratio can be raised so that the usage-amount of said dehydrating agent and dehydration ring-opening agent increases. The imidation ratio is preferably 20% or more from the viewpoint of storage stability. Moreover, as an organic solvent used in a dehydration ring-closure reaction, the organic solvent illustrated as what is used for polyamic-acid synthesis | combination is mentioned. And the reaction temperature of dehydration ring-closure reaction becomes like this. Preferably it is 0-180 degreeC, More preferably, it is 10-150 degreeC. Moreover, the imidation polymer can be refine | purified by performing the same operation as the polyamic-acid purification method with respect to the reaction solution obtained in this way.

<Terminal modified polymer>

The polyamic acid and the imidized polymer may be of terminally modified form with controlled molecular weight. By using this terminal-modified polymer, the coating characteristic of a liquid crystal aligning agent, etc. can be improved, without impairing the effect of this invention. Such a terminally modified polymer can be synthesized by adding an acid-anhydride, a monoamine compound, a monoisocyanate compound, or the like to the reaction system when synthesizing the polyamic acid. Here, examples of the acid-anhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride, n-hexadecylsuccinic anhydride, and the like. Can be. Moreover, as a monoamine compound, for example, aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine , n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n -Ecosyl amine, etc. are mentioned. Moreover, as a monoisocyanate compound, phenyl isocyanate, naphthyl isocyanate, etc. are mentioned, for example.

Logarithmic viscosity of the polymer

The logarithmic viscosity (η ¹ⁿ ) value of the polyamic acid and / or imidized polymer obtained as described above is preferably 0.05 to 10 dl / g, more preferably 0.05 to 5 dl / g.

In the present invention, the value of the logarithmic viscosity (η ¹ⁿ ) is measured by using a N-methyl-2-pyrrolidone as a solvent and measuring the viscosity at 30 ° C. for a solution having a concentration of 0.5 g / 100 ml. Is obtained by

<Liquid crystal aligning agent>

The vertically aligned liquid crystal alignment film of the present invention is preferably obtained by obliquely irradiating unpolarized ultraviolet light to a thin film formed from a liquid crystal aligning agent in which the polyamic acid and / or the imidized polymer is dissolved in an organic solvent.

The temperature at the time of manufacturing the liquid crystal aligning agent used by this invention becomes like this. Preferably it is 0 degreeC-200 degreeC, More preferably, it is 20 degreeC-60 degreeC.

As an organic solvent which comprises a liquid crystal aligning agent, it is 1-methyl- 2-pyrrolidone, (gamma) -butyrolactone, (gamma) -butyrolactam, N, N- dimethylformamide, N, N- dimethylacetamide, for example. , 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxy propionate, ethyl ethoxy propionate, ethylene glycol methyl ether, ethylene glycol ethyl ether , Ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene Glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, and the like. have.

The solid content concentration in the liquid crystal aligning agent is selected in consideration of viscosity, volatility and the like, but is preferably in the range of 1 to 10% by weight. That is, although the liquid crystal aligning agent is apply | coated to the surface of a board | substrate, and forms the thin film used as the liquid crystal aligning film of this invention, when solid content concentration is less than 1 weight%, the film thickness of this thin film becomes too thin and a favorable liquid crystal aligning film is not obtained, solid content When the concentration exceeds 10% by weight, the film thickness of the thin film becomes too thick to obtain a good liquid crystal aligning film, and the viscosity of the liquid crystal aligning agent increases, so that the coating properties tend to be inferior.

The liquid crystal aligning agent used by this invention may contain a functional silane containing compound and an epoxy compound from a viewpoint of improving the adhesiveness to the surface of a board | substrate within the range which does not impair the desired physical property. As such a functional silane containing compound, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 2-aminopropyl trimethoxysilane, 2-aminopropyl triethoxysilane, N- ( 2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltrier Methoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-tri Methoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecan, 10-triethoxysilyl-1,4,7-triazadecan, 9-trimethoxysilyl- 3,6-diazanyl acetate, 9-triethoxysilyl-3,6-diazanyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-ben Jyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltri Methoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, etc. are mentioned. Examples of such epoxy compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, Neopentylglycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentylglycol diglycidyl ether, 1,3,5, 6-tetraglycidyl-2,4-hexanediol, N, N, N ', N'-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl ) Cyclohexane, N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 3- (N-allyl-N-glycidyl) aminopropyltrimethoxysilane, 3- (N, N- diglycidyl) aminopropyltrimethoxysilane etc. are mentioned.

<Liquid crystal aligning film>

The liquid crystal aligning film of this invention can be obtained by apply | coating the said liquid crystal aligning agent to a board | substrate normally, and baking, and irradiating obliquely irradiating unpolarized ultraviolet-ray to less than 90 degree of irradiation angles. As a coating method of a liquid crystal aligning agent, a spin coating method, the printing method, etc. are mentioned, for example, A printing method is preferable. Firing can be performed at 50 to 300 ° C. for 0.5 to 300 minutes. As an ultraviolet irradiation device, a high pressure mercury lamp, a low pressure mercury lamp, a xenon mercury lamp, an excimer laser, etc. can be used. In addition, the irradiation angle is preferably 20 to 70 degrees. In addition, the irradiation intensity is preferably 0.2 to 30 J / cm ² .

<Example>

Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not restrict | limited to these Examples.

[Liquid Crystal Display Device Manufacturing Method]

Fabrication of Liquid Crystal Display Devices:

A liquid crystal aligning agent was applied using a spinner on a transparent conductive film including an ITO film provided on one side of a glass substrate having a thickness of 1 mm, and dried on a hot plate at 180 ° C. for 10 minutes to form a coated film having a dry film thickness of 600 kPa. It was set as the liquid crystal aligning film. The substrate was obliquely irradiated with ultraviolet rays of 2 J / cm ² at a 45 degree angle with a xenon mercury lamp.

Two board | substrates with a liquid crystal aligning film were produced as mentioned above, the epoxy resin adhesive containing an aluminum oxide sphere was apply | coated by the screen printing method to each board | substrate outer edge, and two board | substrates were opposed through a gap. It arrange | positioned, the outer edge part contacted and crimped | bonded and hardened the adhesive agent.

A negative nematic liquid crystal was injected and filled into the cell gap partitioned by the adhesive on the substrate surface and the outer edge portion, and then the injection hole was sealed with an acrylic photocuring adhesive to prepare a vertically aligned liquid crystal display device.

[Orientation]

At the time of voltage off of the vertically-aligned liquid crystal display element, application of 4V alternating current was visually confirmed and observed.

[Voltage retention rate]

After applying a voltage of 5 V to the liquid crystal display element at an application time of 60 microseconds and an interval of 167 milliseconds, the voltage retention after 167 milliseconds from the release of the application was measured. The measurement apparatus used VHR-1 by Toyo Technica.

[Surface tension of thin film]

JOURNAL OF APPLIED POLYMER SClENCE VOL. 13, PP. 1741-1747 (1969)] was obtained from the contact angle of pure water and the contact angle of methylene iodide on the thin film by the method of D.K.OWENS et al.

In a system in which a liquid is in contact with the surface of a solid, the relationship between the surface free energy (surface tension) of the liquid, the surface free energy of the solid, and the contact angle is represented by the following equation.

In the formula, γ ^L : surface free energy of the liquid

γ ^Ld : dispersion component of surface free energy of liquid

γ ^Lp : polar component of the surface free energy of a liquid

γ ^Sd : dispersion component of surface free energy of solid

γ ^Sp : polar component of surface free energy of solid

θ: contact angle

Thus at 20 ° C. for pure water γ ^L = 72.8, γ ^Ld = 21.8 and γ ^Lp = 51.0 (unit is dyn / cm), and for methylene iodide γ ^L = 50.8, γ ^Ld = 49.5 and γ ^Lp = 1.3 (dyn / cm).

Substituting these values into Equation 2 yields Equation 3 below for pure water and Equation 4 below for methylene iodide. Here, θ ¹ and θ ² are the contact angles of pure water and methylene iodide, respectively.

Therefore, γ ^Sd and γ ^Sp were obtained from the simultaneous equations by substituting the measured values of the contact angles into the equations (3) and (4), and the surface free energy γ ^S of the thin film was obtained by the following equation (5).

In addition, the contact angle was measured by using a contact angle measuring device "CA-A type" (manufactured by Kyowa Kaimen Kagaku Co., Ltd.) by adding 4 µl of water or methylene iodide onto the thin film and measuring the contact angle after 1 minute. It was.

<Synthesis Examples 1 to 9 and Comparative Synthesis Example 1>

N-methyl-2-pyrrolidone was added to diamine and tetracarboxylic dianhydride in the order shown in Table 1, and it was made to react for 6 hours, and the polyamic acid which has the logarithmic viscosity shown in Table 1 was obtained.

Synthesis Example Polymerization Concentration (%) Polymerization temperature (℃) Diamine (mmol) Acid anhydride (mmol) Logarithmic viscosity (dl / g) One 20 Room temperature Eq 18 (50) CB (50) 0.7 2 20 Room temperature Eq 18 (50) CB (40) DMCB (10) 0.6 3 20 60 Eq 18 (50) TCAAH (50) 0.7 4 20 60 Eq. 15 (50) TCAAH (50) 0.7 5 20 60 ODDA (50) TCAAH (50) 0.7 6 20 60 15 (5) PDA (45) TCAAH (50) 1.0 7 20 60 15 (12.5) PDA (37.5) TCAAH (50) 0.9 8 20 60 15 (12.5) PDA (37.5) TCAAH (37.5) PMDA (12.5) 1.0 9 20 60 ODDA (50) CB (50) 0.8 Comparative Synthesis Example 20 60 PDA (50) TCAAH (50) 1.2 Formula 15: Diamine represented by Chemical Formula 15 Formula 18: Diamine represented by Chemical Formula 18: octadecanoxy-2,5-diaminobenzenePDA: p-phenylenediamine Cβ: 1,2,3,4 -Cyclobutanetetracarboxylic dianhydride DMCB: 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride TCAAH: 2,3,5-tricarboxycyclopentylacetic dianhydride PMDA: Pyromellitic dianhydride

Synthesis Example 10

The polyamic acid obtained in Synthesis Example 3 was diluted with N-methyl-2-pyrrolidone to a solid content concentration of 5%, and pyridine and acetic anhydride were added 5 times and 3 times, respectively, to the repeating units of the polyamic acid. The imidation reaction was performed at 4 degreeC for 4 hours. After the completion of the reaction, the precipitate was recovered by reprecipitation with methanol and the precipitate was recovered and dried to obtain a white polyimide powder.

Synthesis Example 11

The polyamic acid obtained in Synthesis Example 6 was diluted to 5% solids concentration with N-methyl-2-pyrrolidone, and pyridine and acetic anhydride were added 5 times and 3 times the molar amount, respectively, to the repeating units of the polyamic acid. And imidation reaction was performed at 110 degreeC for 4 hours. After completion of the reaction, the precipitate was reprecipitated with methanol to recover the precipitate and dried to obtain a white polyimide powder.

<Examples 1 to 17 and Comparative Example 1>

Using the polyamic acid, the polyimide obtained in the synthesis example, the solvent of Table 2, and an additive, the liquid crystal aligning agent of 3.0 weight% of solid content concentration was manufactured by the same composition as Table 2. The liquid crystal aligning film was formed using this liquid crystal aligning agent, the liquid crystal display element was produced, and the evaluation was performed. The results are shown in Table 2.

Example polymer menstruum Additive (part by weight) Pretilt angle (degrees) Orientation Voltage retention rate (%) Thin film surface tension (dyn / cm) One Synthesis Example 1 NMP (3) BC (7) 0 89.3 Good 85 32 2 Synthesis Example 2 NMP (3) BC (7) 0 89.3 Good 85 32 3 Synthesis Example 3 NMP (3) BC (7) 0 89.4 Good 85 32 4 Synthesis Example 4 NMP (3) BC (7) 0 89.5 Good 98 31 5 Synthesis Example 5 NMP (3) BC (7) 20 89.5 Good 98 32 6 Synthesis Example 6 NMP (5) BC (5) 20 88.3 Good 98 37 7 Synthesis Example 7 NMP (3) BC (7) 20 89.1 Good 98 34 8 Synthesis Example 8 NMP (3) BC (7) 20 89.0 Good 98 35 9 Synthesis Example 9 NMP (3) BC (7) 0 89.4 Good 98 32 10 Synthesis Example 10 γ-BL (8) BC (2) 0 89.0 Good 87 32 11 Synthesis Example 11 γ-BL (8) BC (2) 0 88.1 Good 98 37 12 Synthesis Example 10 (1) Synthesis Example 1 (99) γ-BL (8) BC (2) 0 89.0 Good 97 32 13 Synthesis Example 10 (1) Synthesis Example 6 (99) γ-BL (8) BC (2) 0 89.0 Good 97 32 14 Synthesis Example 10 (1) Synthesis Example 7 (99) γ-BL (8) BC (2) 0 89.0 Good 97 32 15 Synthesis Example 11 (1) Synthesis Example 1 (99) γ-BL (8) BC (2) 0 88.1 Good 98 37 16 Synthesis Example 11 (1) Synthesis Example 7 (99) γ-BL (8) BC (2) 0 88.1 Good 98 37 Comparative example Comparative Synthesis Example NMP (3) BC (7) 0 - Not vertically oriented - 56 NMP: N-methyl-2-pyrrolidone BC: Butyl cellosolve (ethylene glycol-n-butyl ether) γ-BL: γ-butyrolactone * As an additive, N, N, N ', N'-tetragly Cidyl-4,4'-diaminodiphenylmethane (epoxy compound) was used. The amount of the additive added represents parts by weight with respect to 100 parts by weight of the polymer.

As mentioned above, according to this invention, the liquid crystal aligning film excellent in the perpendicular | vertical liquid-crystal orientation and voltage retention characteristic can be provided by the inclination irradiation of unpolarized ultraviolet-ray.

Claims (7)

The vertical alignment liquid crystal aligning film obtained by irradiating an unpolarized ultraviolet-ray to a thin film with a surface tension of 40 dyn / cm or less at less than 90 degree of irradiation angles. The vertical alignment liquid crystal alignment film according to claim 1, wherein the thin film contains a polymer having at least one repeating unit selected from repeating units represented by the following general formula (1a) and repeating units represented by the following general formula (1b). <Formula 1a> In formula, A <^1> is a tetravalent organic group and B <^1> is group represented by following formula (2a) or (2b). <Formula 1b> In the formula, A ² is a tetravalent organic group, and B ² is a group represented by the following formula (2a) or (2b). <Formula 2a> Wherein X is a divalent group selected from -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH- and -S-, and R ¹ is a hydrocarbon group having 12 to 30 carbon atoms Or a monovalent organic group which is a C6 or more fluorine-containing hydrocarbon group. <Formula 2b> Wherein X is a divalent group selected from -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH- and -S-, and R ² is a hydrocarbon group having 12 to 30 carbon atoms Or a divalent organic group which is a C6 or more fluorine-containing hydrocarbon group. The vertical alignment liquid crystal alignment film according to claim 2, wherein the thin film contains at least one polymer selected from polyamic acid and an imidized polymer having a structure obtained by dehydrating and closing the polyamic acid. The polyamic acid according to claim 2, wherein the thin film is selected from a polyamic acid obtained by ring-opening a tetracarboxylic dianhydride and at least one diamine selected from the formulas 3a and 3b below, and an imidized polymer obtained by dehydrating and closing the polyamic acid. It consists of 1 or more types of polymers which become, The vertical alignment liquid crystal aligning film characterized by the above-mentioned. <Formula 3a> Wherein X is a divalent group selected from -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH- and -S-, and R ¹ is a hydrocarbon group having 12 to 30 carbon atoms Or a monovalent organic group which is a C6 or more fluorine-containing hydrocarbon group. <Formula 3b> Wherein X is a divalent group selected from -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH- and -S-, and R ² is a hydrocarbon group having 12 to 30 carbon atoms Or a divalent organic group which is a C6 or more fluorine-containing hydrocarbon group. The vertically oriented liquid crystal aligning film of Claim 4 whose 50 mol% or more of tetracarboxylic dianhydride is alicyclic tetracarboxylic dianhydride. The vertical alignment liquid crystal aligning agent used in order to obtain the vertical alignment liquid crystal aligning film of Claim 1. The vertical alignment liquid crystal display element provided with the liquid crystal aligning film of Claim 1.