JP2760022B2 - Materials for liquid crystal alignment film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a material for a liquid crystal alignment film, and more particularly to a material for a liquid crystal alignment film having good liquid crystal alignment and a large pretilt angle.

[Conventional technology]

Conventionally, a nematic liquid crystal having a positive dielectric anisotropy is
There is known a liquid crystal display element (TN display element) having a TN type alignment cell in which a transparent electrode coated with a liquid crystal alignment film is sandwiched so that the major axis of liquid crystal molecules is continuously twisted by 90 degrees between substrates. ing. The alignment of the liquid crystal in this liquid crystal display element is formed by rubbing a liquid crystal alignment film made of polyimide or the like applied on the electrode.

Since the TN type display element is inferior in contrast and viewing angle dependency, recently, SBE (Super twisted Birefring) has been used as a liquid crystal display element having excellent contrast and viewing angle dependency.
ency Effect) display elements have become known. This S
The BE display element uses a nematic type liquid crystal as a liquid crystal blended with a caryral agent, which is an optically active substance, and exhibits a birefringence effect caused by the long axis of liquid crystal molecules being continuously twisted by 180 degrees or more between substrates. To use.

[Problems to be solved by the invention]

However, the SBE display element conventionally has a problem that display reproducibility is poor and a manufacturing process is complicated because a substrate on which silicon dioxide groups are obliquely vapor-deposited in order to align liquid crystal is used. .

Further, when an SBE display element is manufactured using a liquid crystal alignment film made of polyimide or the like of the conventional TN type display element, the liquid crystal alignment film has a small pretilt angle between the major axis of the aligned liquid crystal molecules and the liquid crystal alignment film. Cannot be twisted more than 180 degrees between substrates, and it is difficult to obtain a required display function.

The present invention has been made in view of such conventional technical problems, and an object of the present invention is to provide a material for a liquid crystal alignment film having good liquid crystal alignment and a large pretilt angle.

[Means for solving the problem]

The present invention relates to (A) a diamine compound containing a secondary amino group represented by the general formula (I) (hereinafter referred to as “secondary diamine compound (I)) Wherein R ¹ is a divalent organic group, R ² and R ³ are the same or different and are monovalent organic groups containing a hydroxyl group, and (B) tetracarboxylic dianhydride (Hereinafter referred to as "tetracarboxylic acid (I)") and a material for a liquid crystal alignment film containing a polyamic acid formed by a reaction with at least one kind of tetracarboxylic acid selected from derivatives thereof.

R ¹ in the secondary diamine compound (I) used in the present invention
Represents a divalent organic group, such as ethylene, propylene, butylene, pentamethylene, hexamethylene, octamethylene, decamethylene, dodecylmethylene, tetradecamethylene, hexadecamethylene, octamethylene, Aliphatic groups such as decamethylene group; alicyclic groups such as cyclobutene group and cyclohexane group; and aromatic groups such as phenylene group, biphenylene group, naphthalene group and xylylene group. At least one aromatic group is at least one oxygen atom, sulfur atom, thiophene ring, furan ring, carbonyl group, sulfonyl group, methylene group, isopropylidene group, hexafluoropropylene group, Si (R ⁶ ) ₂ (here Wherein R ⁶ is a methyl group, an ethyl group,
Phenyl, etc.).

Further, one of R ² and R ^{3 in} the secondary diamine compound (I)
Examples of the valent organic group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group,
Aliphatic groups such as dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group; alicyclic groups such as cyclopropyl group, cyclobutyl group and cyclohexyl group; phenyl group And aromatic groups such as a biphenyl group, a naphthyl group and a benzyl group.

These aliphatic groups, alicyclic groups or aromatic groups may be substituted with a functional group such as a hydroxyl group, a cyano group, an alkoxy group, an alkylcarbonyl group, an alkoxycarbonyl group, or a halogen atom such as a fluorine atom. Good.

When the material for a liquid crystal alignment film of the present invention is used as a liquid crystal alignment film for an SBE display element, as R ² and R ³ ,
Organic groups having 6 or more carbon atoms, particularly groups having an alkyl group having 6 or more carbon atoms, preferably having 10 to 20 carbon atoms, are preferred.

The secondary diamine compound (I) used in the present invention includes a diamine compound represented by the following general formula (II) (hereinafter referred to as “diamine compound (II)”) and an epoxy compound represented by the following general formula (III) (Hereinafter referred to as “epoxy compound (III)
).

H ₂ NR ₄ —NH ₂ (II) (wherein, R ⁴ represents the same divalent organic group as R ¹ ) Here, the diamine compound (II) includes paraphenylenediamine, meta Phenylenediamine, 4,4'-diaminophenylmethane, 4,4'-diaminodiphenylethane, benzidine, 4,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylether, 1 , 5-diaminonaphthalene,
3,3'-dimethyl-4,4'-diaminobiphenyl, 3,4 '
-Diaminobenzanilide, 3,4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-
Diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2-bis [-(4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 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-hydro-anthracene, 9,9-bis (4-aminophenyl) fluorene, 4,4'-methylene-bis (2-
Chloroaniline), 2,2 ', 5,5'-tetrachloro-4,4'
Aromatic diamines such as diaminobiphenyl, 2,2'-dichloro-4,4-diamino-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl;
Aromatic diamine having a hetero atom such as diaminotetraphenylthiophene; 1,1'-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine , Nonamethylenediamine, 4,4'-dimethylheptamethylenediamine, 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylenediethylenediamine, tricyclo [6 , 2,1,0 ^2.7 ] -aliphatic or cycloaliphatic diamines such as undecylenedimethyldiamine; and (Wherein, R ⁷ represents a methyl group, an ethyl group, or a hydrocarbon group of 1 to 12;
An aliphatic group such as a propyl group, an alicyclic group such as a cyclohexyl group, or an aromatic group such as a phenyl group;
And n represents an integer of 1 to 20).

(In the formula, R ^{8 to} R ¹¹ are the same or different and represent an aliphatic group, an aliphatic group having a double bond, or an aromatic group which may be substituted with a hydrogen atom, a halogen atom or a hydroxyl group.) Specific examples of the epoxy compound (III) include propylene oxide, 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2-epoxyoctane, , 2-epoxynonane, 1,
2-epoxydecane, 1,2-epoxyundecane, 1,2-
Epoxide decane, 1,2-epoxytridecane, 1,2-epoxytetradecane 1,2-epoxypentadecane, 1,
Aliphatic epoxy compounds such as 2-epoxyhexadecane, 1,2-epoxyheptadecane, 1,2-epoxyoctadecane, and 1,2-epoxynonadecane; 3,4-epoxy-1-
Aliphatic epoxy compounds having a double bond such as butene, 1,2-epoxy-5-hexene, 1,2-epoxy-7-octene; styrene oxide, glycidylphenyl ether, glycidyl-4-methoxyphenyl ether, N-
Aromatic epoxy compounds such as (2,3-epoxypropyl) phthalimide and glycidylbiphenyl ether; halogenated epoxy compounds such as epifluorohydrin, epichlorohydrin, epipromohydrin, and the like. Among these, preferred are 1,2-epoxytetradecane, 1,2-epoxypentadecane, 1,2-epoxyhexadecane, 1,2-epoxyheptadecane, 1,2-
It is an aliphatic epoxy compound having 12 to 20 carbon atoms such as epoxy octadecane and 1,2-epoxynonadecane, and a halogenated epoxy compound such as epifluorohydrin.

The reaction between the diamine compound (II) and the epoxy compound (III) is carried out at 0 to 200 ° C. in an anhydrous state in the presence of a catalyst.

Here, as the catalyst, hydrochloric acid, sulfuric acid, boron trifluoride, pyridine, lutidine, collidine, triethylamine and the like are used. At this time, if necessary, a solvent,
For example, solvents such as diethyl ether, dioxane, N-methylpyrrolidone, N, N-dimethylformamide, and N, N-dimethylacetamide can be used.

The diamines (A) in the present invention may contain a secondary diamine compound (I) as an essential component, and may further contain a diamine compound (II) in the diamines (A) as needed.

In this case, the content of the secondary diamine compound (I) in the diamine (A) is preferably 2 to 30 mol%.

Next, the tetracarboxylic acid (I) used in the present invention
Is a compound represented by the following general formula (IV).

(In the formula, R ⁵ represents a tetravalent organic group.) Examples of the tetracarboxylic acid (I) include butanetetracarboxylic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride , 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarbocyclopentylacetic dianhydride, 3,5,6-tricarboxy-norbornane-2-acetic dianhydride, Aliphatics such as 5- (2,5-dioxotetrahydrofuryl) -3-methyl-cyclohexenedicarboxylic dianhydride, bicyclo [2,2,2] -oct-7-ene-tetracarboxylic dianhydride and Alicyclic tetracarbonyl dianhydride; pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylsulfonetetracarboxylic acid Dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenylethertetracarboxylic dianhydride, 3,3', 4,4'-dimethylphenylsilanetetracarboxylic Acid dianhydride, 3,3 ', 4,4'-tetraphenylsilanetetracarboxylic dianhydride 1,2,3,4-furantetracarboxylic dianhydride, 4,4'-bis (3,4 -Dicarboxyphenoxy) diphenyl sulfide dianhydride,
4,4'-bis (3,4-dicarboxyphenoxy (diphenylsulfone dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ', 4,
4'-perfluoroisopropylidenetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenylethertetracarboxylic 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,
Aromatic tetracarboxylic dianhydrides such as bis (triphenylphthalic acid) 4,4'-diphenylmethane dianhydride can be mentioned.

Further, as the tetracarboxylic acid (I), an oligomer having an acid anhydride group at both terminals obtained by reacting the above-described tetracarboxylic acid (I) with a diisocyanate compound can also be used. Here, as the diisocyanate compound, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4 '
-Diphenyl ether diisocyanate, 4,4'-diphenyl sulfone diisocyanate, 4,4'-diphenyl sulfide diisocyanate, 1,5-naphthalenediisocyanate, 2,6-naphthalenediisocyanate, tolidine isocyanate, 4,4'-biphenyl diisocyanate, p-xylyl Aromatic diisocyanates such as diisocyanate and m-xylylene diisocyanate; isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, Alicyclic diisocyanates such as 4'-dicyclohexyl ether diisocyanate; butane diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate DOO, lysine diisocyanate, and aliphatic diisocyanates such as trimethylhexamethylene diisocyanate.

These tetracarboxylic acids (I) can be used alone or in combination of two or more.

The tetracarboxylic acids in the present invention may be derivatives of tetracarboxylic acid (I).

Here, as the derivative of tetracarboxylic acid (I),
Examples thereof include tetracarboxylic acid which is a hydrolyzate of tetracarboxylic acid (I) and tetracarboxylic acid tetraester which is an esterified product of tetracarboxylic acid (I) with the following alcohols (V).

That is, the alcohols (V) include ethanol, propanol, butanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, and octanol. Decanol, Nonadecanol,
Aliphatic alcohols such as eicosanol; 3-ethylcyclobutanol, 2-isopropylcyclopentanol,
Alicyclic alcohols such as 4-tert-butylcyclohexanol; 4-tert-butyl-α-naphthol, 4-tert-butylphenol, p-octylphenol, p-decylphenol, p-pentadecylphenol, p-hexadecylphenol , Aromatic alcohol compounds such as p-octadecylphenol; ω-undecylenyl alcohol;
Aliphatic alcohols having a double bond such as oleyl alcohol and linolenyl alcohol; 2-fluoroethanol, 2,2,2-trifluoroethanol, 1-chloro-2
-Octanol, p-trifluoroethylphenol,
An alcohol containing a halogen atom, such as m-trifluoroethylphenol, may be used. Among these alcohols (V), particularly preferred are tetradecanol, hexadecanol, octadecanol, nonadecanol, eicosanol, p-hexadecylphenol,
alcohols having an aliphatic group having 14 to 20 carbon atoms or an aliphatic group having a double bond, such as p-octadecylphenol, oleyl alcohol, and linoleyl alcohol; and
It is an alcohol containing a halogen atom such as 2,2,2-trifluoroethanol.

The polyamic acid in the present invention is produced by reacting (A) a diamine and (B) a tetracarboxylic acid in the presence of an organic solvent.

The reaction ratio of the (A) diamine and the (B) tetracarboxylic acid is usually in the range of 1 mole of the (A) diamine.
(B) Tetracarboxylic acids 0.5 to 2 mol, preferably 0.8
~ 1.2 mol.

The organic solvent that can be used for the production of the polyamic acids is not particularly limited as long as it can dissolve the polyamic acids. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N- Examples include aprotic polar solvents such as dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, and hexamethylphosphortriamide, and phenol solvents such as m-cresol, xylenol, phenol, and halogenated phenol.

The amount of the organic solvent used is such that the solid concentration is usually 0.1%.
-30% by weight, preferably 0.5-20% by weight.

In addition, the reaction temperature at the time of synthesizing polyamic acids is usually 0 to 100 ° C.

When the polyamic acids thus produced have an acid anhydride group at the terminal, the chain can be extended with a diisocyanate compound.

Examples of the diisocyanate compound include the same compounds as described above.

The polyamic acids in the present invention are easily soluble in an organic solvent, are very stable even in a solution state, and do not show turbidity or change in viscosity even after long-term storage.

The polyamic acids used in the present invention may be partially dehydrated and ring-imidized in the above-mentioned production step, or may be partially imidized after production.

As a method of partially imidizing the polyamic acids, a solution in which the polyamic acids are dissolved in the same solvent as described above, a dehydrating agent equivalent to the amide bond to be imidized of the polyamic acids, and 50 to 50 A method in which 300 equivalents of a basic catalyst are mixed, and dehydration and a ring closure reaction are performed at 0 to 200 ° C.

Examples of the dehydrating agent used include anhydrides of organic acids such as acetic anhydride, trifluoroacetic anhydride, and propionic anhydride.

Examples of the basic catalyst include organic amines such as pyridine, lutidine, collidine, and triethylamine.

Intrinsic viscosity [η _inh =
(L _n η _ret ) / c, c = 0.5 g / dl, 30 ° C., in dimethylacetamide] is usually 0.05 to 10 dl / g, preferably 0.05 to 10 dl / g.
It is 5dl / g.

Further, the polyamic acids in the present invention can be used by mixing with other polyamic acids and polyamides in an arbitrary ratio. This mixing ratio depends on the required value of the pretilt angle, and is not particularly limited.

The material of the present invention is usually obtained by dissolving the polyamic acids thus obtained in an organic solvent, and having a solid content of 0.1 to 30% by weight.
It is preferably prepared as a 0.5 to 20% by weight solution.

Examples of the organic solvent here include the same organic solvents as those used for producing polyamic acids.

In this case, the organic solvent includes alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons such as methyl alcohol, ethyl alcohol, isopropyl alcohol, Hexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate,
Butyl acetate, 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, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene , Hexane, heptane, octane, benzene,
Toluene, xylene and the like can be mixed to such an extent that polyamic acids are not precipitated.

The liquid crystal display device obtained by using the material of the present invention can be manufactured, for example, by the following method.

First, a transparent conductive film is provided on a substrate, and the solution is applied to the transparent conductive film side of the substrate by a roll coater method, a spinner method, a printing method, or the like to form a coating film.
The liquid crystal alignment film is formed by heating at a temperature of 80 to 200 ° C, preferably 120 to 200 ° C.

The dry film thickness of this coating film (liquid crystal alignment film) is usually 0.001
１1 μm, preferably 0.005 to 0.5 μm.

In the liquid crystal display element, a silane coupling agent, a titanium coupling agent, and a titanium coupling agent may be previously provided on the substrate and the transparent conductive film in order to further improve the adhesion between the substrate and the transparent conductive film and the liquid crystal alignment film. A ring agent or the like can be applied.

Further, as a substrate used for a liquid crystal display element obtained by using the material of the present invention, float glass, soda glass or flexible polyethylene terephthalate, polyester film such as polybutylene terephthalate, further polyether sulfone, polycarbonate, can be used a transparent substrate made of other plastic film, the transparent conductive film, NESA film made of SnO _2,
An ITO film made of In ₂ O ₃ -SnO ₂ can be used, and the patterning of these electrodes can be performed by a photo-etching method,
A method using a mask is used in advance.

The liquid crystal alignment film thus obtained is rubbed with a roll wrapped around a cloth made of synthetic fiber such as nylon.
Liquid crystal alignment processing is performed, and liquid crystal is sealed.

Here, the liquid crystal is sealed by sealing the peripheral portion between the pair of substrates treated as described above with a sealant, and sealing the filling port with a sealant to form a liquid crystal cell. A liquid crystal display device is obtained by pressing a polarizing plate in parallel.

As the sealing agent, for example, an epoxy resin containing a hardening agent and aluminum oxide spheres as a spacer can be used.

The liquid crystal used for the liquid crystal display element is not particularly limited as long as it has a positive dielectric anisotropy, but is preferably a liquid crystal that forms a nematic liquid crystal, such as a Schiff base liquid crystal, an azoxy liquid crystal, and a biphenyl liquid crystal. And phenylcyclohexane-based liquid crystal, S-based liquid crystal, terphenyl-based liquid crystal, biphenylcyclohexane-based liquid crystal, pyrimidine-based liquid crystal, dioxane-based liquid crystal, bicyclooctane-based liquid crystal, and Cuban-based liquid crystal.

These liquid crystals are usually used as a mixture,
It may be used alone.

Furthermore, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonaate, and cholesteryl carbonate, and chiral agents such as those sold under the trade names C-15 and CB-15 (manufactured by British Drug House), etc. Can be added for use.

Also, p-decyloxybenzylidene-p'-amino-
Ferroelectric liquid crystals such as 2-methylbutylcinnamate can also be used.

Further, as the sealing agent, there are an organic sealing agent and an inorganic sealing agent, and the organic sealing agent is particularly preferable because it can be operated at a low temperature.

Examples of the polarizing plate used outside the liquid crystal cell include a polarizing plate in which a polarizing film called an H film, in which polyvinyl alcohol is stretched and oriented while absorbing iodine, is sandwiched by a cellulose acetate protective film or a polarizing plate made of the H film itself. Can be mentioned.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Incidentally, the measurement of the pretilt angle in the examples is (T.
J. Schffer, et.J. Appl. Phys., 48 , 1783 (1977), F. Nakan
o, et.al., JPN, J. Appl. Phys., 19 , 2013 (1980)] according to a crystal rotation method using He-Ne laser light.

Example 1 19.8 g of 4,4'-diaminodiphenylmethane and 1,2-
9.40 g of epoxy octadecane was added to N-methylpyrrolidone 4
It was dissolved in 64.4 g and reacted at 120 ° C. for 8 hours. The obtained reaction solution was cooled to room temperature, and 22.4 g of 2,3,5-
After addition of tricarboxycyclopentyl acetic acid dianhydride, the reaction was carried out at 60 ° C. for 4 hours. The obtained reaction solution is
3 l of a 1% by weight aqueous hydrochloric acid solution were added dropwise to precipitate a polymer.

The polymer was separated by filtration with a glass filter, washed sufficiently with a large amount of methanol, purified, and then dried under reduced pressure.

The reaction formula of the diamine compound represented by the general formula (I) obtained by reacting 4,4'-diaminodiphenylmethane with 1,2-epoxyoctadecane in the present example is as follows.

The intrinsic viscosity of the polymer obtained as described above is 30
° C., measured in N, N-dimethylacetamide,
It was 0.86 dl / g.

Further, the content of the structural unit consisting of the diamine represented by the general formula (I) and the tetracarboxylic acid (I) in the obtained polymer was measured by ¹ H-NMR spectrum.
3 mol%.

Next, an N-methylpyrrolidone / butyl cellosolve (70/30, weight ratio) solution of the obtained polymer (solid content: 5
% By weight), and this solution was filtered through a filter having a pore size of 1 μm to prepare a liquid crystal alignment film solution.

This solution was applied on a transparent electrode surface on a glass substrate with a transparent electrode made of an ITO film using a spinner at a rotation speed of 3,000 rpm for 3 minutes, and dried at 180 ° C. for 3 hours.
m of the liquid crystal alignment film was formed.

A rubbing machine having a roll around which a nylon cloth was wound was rubbed on the obtained liquid crystal alignment film at a roll rotation speed of 500 rpm and a stage moving speed of 1 cm / sec.

Next, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 17 μm is screen-printed and applied to the outer edges of each of the pair of rubbed substrates having the liquid crystal alignment film, and then the pair of substrates is rubbed up and down. The adhesive was hardened by overlapping and pressure bonding so as to be antiparallel, and a chamber for filling liquid crystal was left inside.

Next, after injecting a nematic liquid crystal (ZLI-1565, manufactured by Merck) from the liquid crystal injection port, sealing the liquid crystal injection port with an epoxy-based adhesive, and polarizing plates on both outer surfaces of the obtained device, The liquid crystal display devices were manufactured by laminating the polarizing plates so that the polarizing directions of the polarizing plates coincided with the rubbing directions of the liquid crystal alignment films applied to the respective substrates.

The liquid crystal orientation of the obtained liquid crystal display device was good, and the pretilt angle was measured and found to be 60 degrees or more.

Examples 2 to 5 In Example 1, the amount of 1,2-epoxyoctadecane used was changed, and the content of the diamine unit represented by the general formula (I) in the polymer was changed as shown in Table 1. Except for the above, a polymer was obtained in the same manner as in Example 1, a liquid crystal alignment film solution was prepared in the same manner as in Example 1, and a liquid crystal display device was produced.
evaluated.

 The results are shown in Table 1.

Example 6 In the same manner as in Example 1, 19.8 g of 4,4'-diaminodiphenylmethane and 2.68 g of 1,2-epoxyoctadecane were reacted, and 22.4 g of 2,3,5-tricarboxycyclopentylacetic acid dianhydride was further reacted. And then the polymer was precipitated.

Next, the polymer was purified and dried in the same manner as in Example 1, and then dissolved in N-methylpyrrolidone to prepare a 5% by weight solution. This solution was heated to 60 ° C., and 39.6 g of pyridine and 30.6 g of acetic anhydride were sequentially added thereto with stirring, followed by reaction at 120 ° C. for 5 hours. The obtained reaction solution is
The mixture was poured into a large amount of methanol to precipitate the polymer, which was separated by filtration with a glass filter, washed with methanol, and dried under reduced pressure.

The intrinsic viscosity of the polymer obtained as described above is 30
° C., measured in N, N-dimethylacetamide,
It was 0.78 dl / g.

The content of the structural unit composed of the diamine represented by the general formula (I) and the tetracarboxylic acid (I) in the obtained polymer was 5 mol% as measured from the ¹ H-NMR spectrum. It was shown that the remaining amic acid units consisted of a dehydrated ring-closed imide structure.

Next, an N-methylpyrrolidone / butyl cellosolve (70/30, weight ratio) solution of the obtained polymer (solid content: 5
% By weight), and a liquid crystal display device was prepared and evaluated in the same manner as in Example 1. The orientation of the liquid crystal display device was good.
When the pretilt angle was measured, it was 45 degrees.

Comparative Example 1 19.8 g of 4,4'-diaminodiphenylmethane and 2,3,5
Using 22.4 g of tricarboxycyclopentylacetic acid dianhydride, the mixture was reacted in N-methylpyrrolidone at 60 ° C. for 4 hours, after which the polymer was precipitated.

Next, the polymer was purified and dried in the same manner as in Example 1.

The intrinsic viscosity of the obtained polymer measured at 30 ° C. in N, N-dimethylacetamide was 1.15 dl / g. When the obtained polymer was evaluated in the same manner as in Example 1, the pretilt angle was 1.2 degrees.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY The liquid crystal alignment film material of the present invention has good alignment properties and a large pretilt angle, so that a liquid crystal alignment film particularly suitable for an SBE display element can be obtained.

Further, the liquid crystal display element using the material for a liquid crystal alignment film of the present invention can be suitably used for a TN type display element or a ferroelectric display element by selecting a liquid crystal to be used.

Furthermore, a liquid crystal display element using the material for a liquid crystal alignment film of the present invention has excellent liquid crystal alignment and reliability, and is combined with a polarizing plate such as a linear polarizing plate or a circular polarizing plate.
It can be effectively used for various devices, and is used for display devices such as desktop calculators, watches, clocks, coefficient display boards, word processors, personal computers, and liquid crystal televisions.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yukihiro Hosaka 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd. (56) References JP-A-63-23131 (JP, A) (58) Surveyed field (Int.Cl. ⁶ , DB name) G02F 1/1337-1/1337 530

Claims (1)

(57) [Claims] 1. A diamine compound having a secondary amino group represented by the general formula (I): Wherein R ¹ is a divalent organic group, R ² and R ³ are the same or different and are monovalent organic groups containing a hydroxyl group, and (B) tetracarboxylic dianhydride And at least one kind of tetracarboxylic acids selected from the group consisting of: and a derivative thereof;