KR20150039675A - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display device - Google Patents

Abstract

The purpose of the present invention is to provide a liquid crystal aligning agent wherein the rubbing resistance of a film is compatible at a high level with the excellent electric characteristics (high voltage holding ratio and inhibited residual voltage) of an obtained liquid crystal alignment film. The liquid crystal aligning agent comprises: (A) a polymer having a structure derived from diamine having carboxyl groups; and (B) a polymer having a structure derived from diamine having tertiary nitrogen atoms, wherein MA/MB, which is the ratio of the molar number MA of carboxyl groups in polymer (A) to the molar number MB of tertiary nitrogen atoms in polymer (B), ranges from 0.15 to 3.50.

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element,

The present invention relates to a liquid crystal aligning agent. Specifically, the present invention relates to a liquid crystal aligning agent which gives a liquid crystal display element excellent in rubbing resistance of a formed coating film and excellent in afterimage characteristics even when driven continuously for a long time.

For example, a twisted nematic (TN) type, a super-twisted nematic (STN) type, a VA (twisted nematic) type, a VA a liquid crystal display element such as a vertical alignment type, a multi-domain vertical alignment (MVA) type, an in-plane switching (IPS) type, a fringe field switching (FFS) type or a polymer-sustained alignment (PSA) type is known.

In such liquid crystal display devices, a liquid crystal alignment film is used to align liquid crystal molecules in the liquid crystal cell. As a liquid crystal alignment film, a coating film made of, for example, polyamic acid, polyimide, or polyorganosiloxane is widely used from the viewpoints of heat resistance, mechanical strength, affinity with liquid crystal, and the like.

The liquid crystal alignment layer has a high alignment ability, a high contrast, a high contrast for a long period of time, and a performance that does not cause a residual phenomenon even when the liquid crystal molecules are continuously driven for a long time. In other words, there is a demand for a liquid crystal alignment film having a good liquid crystal alignment, a high voltage holding ratio, and a small residual voltage after application of a direct current voltage.

In order to satisfy the above requirements, proposals have been made to introduce a carboxyl group, a carbonic acid anhydride group and a tertiary nitrogen atom into polymer chains such as polyamic acid and polyimide (Patent Documents 1 and 2). According to these techniques, it is pointed out that the rubbing resistance of the coating film is insufficient although certain improvement is seen in the electric characteristics of the liquid crystal alignment film.

That is, in a driving method (for example, a TN type, an IPS type, an FFS type, etc.) in which liquid crystal molecules are horizontally aligned, a rubbing process is performed to impart a liquid crystal alignment capability to a coating film formed on a substrate. In general, when the rubbing strength is increased, stronger liquid crystal alignability is exhibited and display defects are less likely to occur. However, if the rubbing strength is excessively strong, excessive force is exerted between the film and the fabric, so that peeling occurs in the film and the fabric, which may adhere to the film. Such redeposition of the exfoliated product leads to display failure in the liquid crystal display element, which leads to a reduction in the yield in the liquid crystal alignment film production process.

A liquid crystal aligning agent which gives a liquid crystal alignment film with a high voltage retaining rate and a small residual voltage after application of a direct current voltage and has a high rubbing strength of a coating film has not been known heretofore.

Japanese Patent Application Laid-Open No. 8-76128 International Publication No. 2009/93709 Japanese Laid-Open Patent Publication No. 2010-97188 International Publication No. 2009/96598

The present invention is intended to overcome the above-described present situation in the prior art. Accordingly, it is an object of the present invention to provide a liquid crystal aligning agent which is compatible with a rubbing resistance of a coating film and a good electric characteristic (voltage holding ratio and residual voltage) of the resulting liquid crystal alignment film at a high level.

According to the present invention,

(A) a polymer having a structure derived from a diamine having a carboxyl group,

(B) a polymer having a structure derived from a diamine having a tertiary nitrogen atom, and

The (A) liquid crystal alignment, characterized in that the number of moles of carboxyl groups in the polymer and the M _A (B) the number of moles of a tertiary nitrogen atom in the polymer of the non-M _A / M _B is from 0.15 to 3.50 with the _B M Lt; / RTI >

Since the coating film formed from the liquid crystal aligning agent of the present invention has high rubbing resistance, it is possible to impart strong liquid crystal alignability by rubbing treatment. Further, since the obtained liquid crystal alignment film has a high voltage holding ratio and a reduced residual electric charge, it gives a liquid crystal display element which is excellent in contrast and is hard to cause afterimage even in continuous driving for a long time.

Therefore, the liquid crystal display device manufactured using the liquid crystal aligning agent of the present invention can be effectively applied to various devices, and for example, it can be applied to various devices such as a clock, a portable game, a word processor, a notebook type personal computer, It can be used for a display device such as a camcorder, a PDA, a digital camera, a mobile phone, a smart phone, various monitors, and a liquid crystal television. Particularly, it is suitable to be applied to a liquid crystal television in which long-time driving is assumed, a display for public display in an airport / station, a display for advertisement, and the like.

(Mode for carrying out the invention)

The liquid crystal aligning agent of the present invention, as described above,

(A) a polymer having a structure derived from a diamine having a carboxyl group,

(B) a diamine having a tertiary nitrogen atom. The polymer (A) preferably does not have a structure derived from a diamine having a tertiary nitrogen atom,

It is preferable that the polymer (B) does not have a structure derived from a diamine having a carboxyl group. The liquid crystal aligning agent of the present invention,

(A) a polymer having a structure derived from a diamine having a carboxyl group but not having a structure derived from a diamine having a tertiary nitrogen atom and

(B) a polymer having a structure derived from a diamine having a tertiary nitrogen atom but having no structure derived from a diamine having a carboxyl group, and a structure derived from a diamine having a carboxyl group and a tertiary nitrogen atom Containing diamine having a structure derived from a diamine, but it is preferable that it does not contain such a polymer.

The "tertiary nitrogen atom" in the present specification does not include a nitrogen atom forming an imine structure and a nitrogen atom in a heteroaromatic ring.

Examples of the basic skeleton of the (A) polymer and the (B) polymer contained in the liquid crystal aligning agent of the present invention include imidized polymers of polyamic acid and polyamic acid, polyamic acid ester, polyester, polyamide, polysiloxane, , Polyacetal, polystyrene derivatives, poly (styrene-phenylmaleimide) derivatives, and poly (meth) acrylates. The polymer (A) and the polymer (B) are each independently at least one polymer selected from the group consisting of imidized polymers of polyamic acids and polyamic acids and polyamic acid esters. It is preferable that the polymers have affinity with liquid crystal molecules, From the viewpoints of the expression of liquid crystal alignability and adhesion to a substrate. Further, the polymer (A) and the polymer (B) may be selected from pyromellitic acid dianhydride, 4,4'-oxydiphthalic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,4,5-cyclohexanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro- Furan-1, 3-dione and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2, 4,6: 8-2 anhydride is preferable because a liquid crystal aligning agent having excellent stability over time is obtained.

<(A) Polymer>

The polymer (A) contained in the liquid crystal aligning agent of the present invention is a polymer having a structure derived from a diamine having a carboxyl group. The polymer (A) preferably does not have a structure derived from a diamine having a tertiary nitrogen atom.

The polymer (A) is preferably at least one polymer selected from the group consisting of imidized polymers of polyamic acid and polyamic acid, and polyamic acid ester, although the requirements other than those mentioned above are not particularly limited.

These preferred polymers will be described below in order.

[Polyamic acid]

The polyamic acid as the polymer (A) in the present invention can be synthesized preferably by reacting a tetracarboxylic acid dianhydride with a diamine containing a diamine having a carboxyl group.

- tetracarboxylic dianhydride -

Examples of the tetracarboxylic acid dianhydride used for synthesizing the polymer (A) in the present invention include aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aromatic tetracarboxylic dianhydrides. have. As specific examples of these,

Examples of the aliphatic tetracarboxylic acid dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride and the like;

As the alicyclic tetracarboxylic acid dianhydride, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,2,4,5- Cyclohexanetetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c ] Furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) 1,2-c] furan-1,3-dione, 3-oxabicyclo [3.2.1] octane-2,4-dione- Dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy- Methyl norbornane-2: 3,5: 6-2 anhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-2 anhydride, Dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, cyclohexanetetracarboxylic acid dianhydride and the like;

As aromatic tetracarboxylic acid dianhydrides, for example, pyromellitic dianhydride, 4,4'-oxydiphthalic dianhydride and the like,

And tetracarboxylic acid dianhydride described in Patent Document 3 (Japanese Unexamined Patent Application Publication No. 2010-97188), and it is preferable to use at least one selected from these.

Examples of the tetracarboxylic acid dianhydride used for synthesizing the polymer (A) in the present invention include pyromellitic dianhydride, 4,4'-oxydiphthalic dianhydride, 1,2,3,4- Cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b- (Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione and 2,4,6,8-tetracarboxybis Cyclo [3.3.0] octane-2: 4, and 6: 8-2 anhydride, and at least one selected from the group consisting of the tetracarboxylic acid dianhydride More preferably 55 mol% or more, and particularly preferably 75 mol% or more, based on the total amount of the copolymer.

- diamine -

The diamine used for synthesizing the polymer (A) in the present invention includes a diamine having a carboxyl group.

As the diamine having a carboxyl group, for example, there can be mentioned a compound represented by the following formula (A1):

(In the formula (A1), m is an integer of 1 to 4,

And Ar is an organic compound having an aromatic ring and having 6 to 30 carbon atoms, which is an (m + 2) -valent organic group).

Examples of Ar in formula (A1) include groups obtained by removing m + 2 hydrogen atoms from aromatic hydrocarbons such as benzene, biphenylene, terphenylene, 2,2-diphenylpropane and naphthalene . m is preferably 1.

As the diamine having a carboxyl group in the present invention, diaminobenzoic acid is preferable, and 3,5-diaminobenzoic acid is particularly preferable.

As the diamine used for synthesizing the polymer (A) in the present invention, only the diamine having a carboxyl group as described above may be used, and other diamines other than the diamine having the carboxyl group may be used in combination.

Examples of other diamines usable herein include aliphatic diamines, alicyclic diamines, aromatic diamines, diaminoorganosiloxanes, and the like. Specific examples of these diamines include aliphatic diamines such as m-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine and the like;

Examples of the alicyclic diamine include 1,4-diaminocyclohexane, 4,4'-methylenebis (cyclohexylamine), and 1,3-bis (aminomethyl) cyclohexane.

The aromatic diamine can be classified into an aromatic diamine having a liquid crystal aligning group and an aromatic diamine having no liquid crystal aligning group. Here, the liquid crystal aligning group includes a group having a steroid structure, a group having an alkyl group having 4 or more carbon atoms, a group having an alkoxy group having 4 or more carbon atoms, a group having a fluoroalkyl group having 1 or more carbon atoms, a group having a fluoroalkoxy group having 1 or more carbon atoms, A group in which two or more of the ring structures selected from a ring and cyclohexane ring are connected directly or via a bonding group, and a group having a plurality of these rings.

Specific examples of the aromatic diamine having such a liquid crystal aligning group include, for example, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3,5-diaminobenzene, cholestanyloxy- 4-diaminobenzene, 3,5-diaminobenzoic acid cholestanyl, 3,5-diaminobenzoic acid cholestenyl, 3,5-diaminobenzoic acid lanostanyl, 3 (4-aminophenoxy) cholestane, 4- (4'-trifluoromethoxybenzoyloxy) cyclohexyl-3,5-dia Diaminobenzoate, 1,1-bis (4 - ((aminophenyl) methyl) phenyl) -4-butyl (4-trifluoromethylbenzoyloxy) cyclohexyl- 4-heptylcyclohexane, 1,1-bis (4 - ((aminophenoxy) methyl) phenyl) -4-heptylcyclohexane, Hexane, 1,1-bis (4 - ((aminophenyl) methyl) phenyl) -4- 1,3-diamino-4-octadecyloxybenzene, 3- (3,5-diaminobenzoyloxy) cholestane, 3,6-bis (4-aminobenzoyloxy) cholestane, And a compound represented by the formula (D-1):

^Wherein X ¹ and X ² each independently represent a single bond, -O-, -COO- or -OCO-, and R ^I and R ^II each independently represent a single bond, A is 0 or 1, b is an integer of 0 to 2, c is an integer of 1 to 20, n is 0 or 1, provided that a and b are both 0 at the same time none).

Specific examples of the group "-C _c H _{2c +1} " include a methyl group, an ethyl group, a n-propyl group, an n-butyl group, an n-pentyl group, n-heptadecyl, n-heptadecyl, n-octadecyl, n-hexadecyl, n-hexadecyl, An n-nonadecyl group, and an n-eicosyl group. The two amino groups in the diaminophenyl group are preferably in the 2,4-position or the 3,5-position with respect to the other groups.

Specific examples of the compound represented by the formula (D-1) include compounds represented by the following formulas (D-1-1) to (D-1-5).

Specific examples of the aromatic diamine having no liquid crystal aligning group include aromatic diamines such as p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 1,5-diaminonaphthalene , 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 2,7- 4,4'-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9- 4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '- (p- phenylenediisopropylidene) , 4 '- (m-phenylene diisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4'- -Aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, 1- (4- Trimethyl-1H-inden-6-amine, (4-aminophenyl Aminophenethyl), 3,5-diaminobenzoic acid, 4-aminobenzylamine, 3-aminobenzylamine, diethylene glycol bis (4-aminophenyl) Ether, 4,4'-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, Diamine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N-phenyl- .

Examples of the diaminoorganosiloxane include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane and compounds represented by the following formula (DA1).

As the diamine used for synthesizing the polyamic acid in the present invention, the diamine described in Patent Document 3 (Japanese Patent Laid-Open Publication No. 2010-97188) can be used in addition to the above.

As the other diamines used for synthesizing polyamic acid in the present invention, it is preferable to use at least one selected from the above-mentioned diamines. However, it is preferable that the diamine does not contain a diamine having a tertiary nitrogen atom.

The diamine used for synthesizing the polyamic acid as the polymer (A) in the present invention preferably contains 5 mol% or more, and preferably 5 mol% to 60 mol%, of the diamine having a carboxyl group based on the total diamine , More preferably 10 to 50 mol%. The diamine used for synthesizing the polyamic acid as the polymer (A) is preferably 4,4'-diaminodiphenyl ether, 4,4'-ethylenedianiline, (4-aminophenyl) -4-aminobenzoate, 4 , 4'-diaminodiphenylmethane, and a compound represented by the formula (DA1), and it is preferable that these structures have a structure derived from 5 To 95 mol%, and more preferably 10 to 90 mol%. The diamine used for synthesizing the polyamic acid as the polymer (A) preferably contains an aromatic diamine in an amount of 60 mol% or more, more preferably 80 mol% or more, relative to the total diamine. When the diamine having a carboxyl group is an aromatic diamine, the diamine also includes 4,4'-diaminodiphenyl ether, 4,4'-ethylenedianiline, (4-aminophenyl) -4 -Aminobenzoate, 4,4'-diaminodiphenylmethane, and a compound represented by the above formula (DA1).

When the liquid crystal aligning agent of the present invention is applied to a TN type or STN type liquid crystal display device, the diamine used for synthesizing polyamic acid is preferably an aromatic diamine having a liquid crystal aligning group in an amount of not more than 20 mol% , More preferably in the range of 2 to 15 mol%, and particularly preferably in the range of 10 to 15 mol%. On the other hand, when the liquid crystal aligning agent of the present invention is applied to a liquid crystal display element of the IPS type or FFS type, the diamine used for synthesizing polyamic acid is preferably such that the ratio of the aromatic diamine having a liquid crystal aligning group to the total diamine, Is preferably in the range of 5 mol% or less, more preferably 3 mol% or less, and particularly preferably not.

- Synthesis of polyamic acid -

The polyamic acid as the polymer (A) in the present invention can be produced by reacting the above tetracarboxylic acid dianhydride and diamine with a suitable molecular weight regulator (for example, acid anhydride, monoamine compound, monoisocyanate compound, etc.) ) In a suitable organic solvent in accordance with a known method.

The ratio of the tetracarboxylic acid dianhydride and the diamine to be used in the synthesis reaction of the polyamic acid is preferably 0.2 to 2 equivalents of the tetracarboxylic acid dianhydride to the equivalent of 1 equivalent of the amino group of the diamine, To 1.2 equivalents is more preferable. The synthesis reaction of the polyamic acid is preferably carried out in an organic solvent. The reaction temperature is preferably -20 ° C to 150 ° C, more preferably 0 ° C to 100 ° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

Examples of the organic solvent used in the reaction include non-protic polar solvents, phenol solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons.

Specific examples of the organic solvent include non-protonic polar solvents such as N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N- N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, gamma -butyrolactone, tetramethylurea, hexamethylphosphoric triamide, 3-methoxy- 3-butoxy-N, N-dimethylpropionamide and the like;

As the phenolic solvent, for example, phenol, m-cresol, xylenol, halogenated phenol and the like;

As the alcohol, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether and the like;

As ketones, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like; Examples of esters include ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate, isoamyl propionate , Isoamyl isobutyrate, diacetone alcohol and the like;

As the ether, for example, 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 monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetraethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, Hydrofuran, diisopentyl ether and the like;

As the halogenated hydrocarbons, for example, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene and the like; Examples of hydrocarbons include hexane, heptane, octane, benzene, toluene, xylene, and the like.

Among these organic solvents, at least one kind selected from the group consisting of an aprotic polar solvent and a phenol type solvent (first group of organic solvents), or at least one kind selected from an organic solvent of the first group, It is preferable to use a mixture of at least one member selected from the group consisting of ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (organic solvent of the second group). In the latter case, the use ratio of the organic solvent of the second group is preferably 50% by weight or less, more preferably 40% by weight or less, based on the total amount of the organic solvent of the first group and the organic solvent of the second group, Or less, and more preferably 30 wt% or less.

The amount (a) of the organic solvent used is preferably such that the total amount (b) of the tetracarboxylic acid dianhydride and the diamine is 0.1 to 50% by weight based on the total amount (a + b) of the reaction solution.

As described above, a reaction solution obtained by dissolving polyamic acid is obtained. The reaction solution may be directly supplied to the preparation of the liquid crystal aligning agent. Alternatively, the polyamic acid contained in the reaction solution may be isolated and then supplied to the preparation of the liquid crystal aligning agent, or after the isolated polyamic acid is purified, . When the polyamic acid is dehydrated and cyclized to obtain an imidized polymer, the reaction solution may be directly supplied to the dehydration ring-closing reaction, or the polyamic acid contained in the reaction solution may be isolated and then subjected to a dehydration ring- The crude acid may be purified and then subjected to a dehydration ring-closing reaction. The polyamic acid can be isolated and purified by a known method.

[Imidized polymer of polyamic acid]

The imidized polymer of the polyamic acid as the polymer (A) in the present invention can be synthesized by dehydrating and cyclizing the above-mentioned polyamic acid to imidize it.

This imidized polymer may be a completely imidized product obtained by dehydrating and ring closure of all of the arid acid structures possessed by the polyamic acid which is a precursor. The imidated polymer may be subjected to dehydration ring closure of only a part of the arid acid structure to form a partial imide cargo . The imide ratio of the polyimide in the present invention is preferably 40% or more, more preferably 50 to 95%, from the viewpoint of increasing the voltage holding ratio. The imidization rate is a percentage of the ratio of the number of imide ring structures to the sum of the number of amide structure and the number of imide ring structure of polyimide. Here, a part of the imide ring may be an isoimide ring.

The dehydration ring-closure of the polyamic acid can be carried out, for example, by a method of heating, or by using a dehydrating agent and a dehydration ring-closing catalyst according to a known method. Of these, the dehydrating agent and the dehydration ring-closing catalyst are preferably used.

In the method of imidizing a polyamic acid solution by adding a dehydrating agent and a dehydrating ring-opening catalyst, an acid anhydride such as acetic anhydride, anhydrous propionic acid or trifluoroacetic anhydride can be used as the dehydrating agent. The amount of the dehydrating agent to be used is preferably 0.01 to 20 mol based on 1 mol of the acid structure of the polyamic acid. As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, collidine, lutidine and triethylamine can be used. The amount of the dehydration ring-closing catalyst to be used is preferably 0.01 to 10 mol based on 1 mol of the dehydrating agent to be used. Examples of the organic solvent used in the dehydration ring-closure reaction include the organic solvents exemplified for use in the synthesis of polyamic acid. The reaction temperature of the dehydration cyclization reaction is preferably 0 to 180 캜, more preferably 10 to 150 캜. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

In this way, a reaction solution containing an imidized polymer of polyamic acid is obtained. This reaction solution may be provided as it is in the preparation of a liquid crystal aligning agent, or may be supplied to the preparation of a liquid crystal aligning agent after removing the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution. Alternatively, after the polyimide is isolated, Or may be added to the preparation of a liquid crystal aligning agent after purification of the isolated polyimide. These purification operations can be carried out according to a known method.

[Polyamic acid ester]

The polyamic ester as the polymer (A) in the present invention can be synthesized, for example, by the following method.

(1) a method of reacting a compound selected from a compound having a polyamic acid and a hydroxyl group, a compound having a halogenide and an oxiranyl group, or

(2) A method of reacting a tetracarboxylic acid diester or a tetracarboxylic acid diester dihalide with a diamine.

The polyamic acid used in the above method (1) is the same as the polyamic acid as the (A) polymer in the present invention. Therefore, it includes a structure derived from a diamine having a carboxyl group, and preferably includes pyromellitic dianhydride, 4,4'-oxydiphthalic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro Furanyl) -naphtho [l, 2-c] furan-l, 3-dione and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane- 2: 4, and 6: 8-2 anhydride, and further includes a structure derived from at least one kind of compound selected from the group consisting of 2: 4,6: 8-2 anhydride.

Examples of the compound having a hydroxyl group used in the method (1) include an alcohol and a phenol compound. Specific examples thereof include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, t-butanol and the like;

Examples of the phenol compound include phenol, cresol, and the like.

Examples of the halide include methyl bromide, ethyl bromide, n-propyl bromide, isopropyl bromide, n-butyl bromide, isobutyl bromide, sec-butyl bromide, t- butyl bromide, stearyl bromide, Ethyl, n-propyl chloride, isopropyl chloride, n-butyl chloride, isobutyl chloride, sec-butyl chloride, t-butyl chloride, stearyl chloride, 1,1,1-trifluoro-2- of;

Examples of the compound having an oxiranyl group include propylene oxide and the like.

The reaction of a polyamic acid with a compound selected from a compound having a hydroxyl group, a compound having a halogenide and an oxiranyl group can be carried out in accordance with a known method.

The tetracarboxylic acid diester used in the above method (2) can be obtained, for example, by ring opening of the tetracarboxylic dianhydride exemplified above for use in the synthesis of polyamic acid by alcohol. The alcohol used here is the same as the alcohol as the hydroxyl group-containing compound used in the above method (1). The tetracarboxylic acid diester dihalide can be obtained by reacting the tetracarboxylic acid diester obtained as described above with a suitable chlorinating agent. Examples of the chlorinating agent include thionyl chloride and the like. The tetracarboxylic acid dianhydride used as a raw material for these compounds is the same as the tetracarboxylic dianhydride for synthesizing the polyamic acid as the polymer (A) in the present invention. Accordingly, it is preferable to use pyromellitic dianhydride, 4,4'-oxydiphthalic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid Acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl ) -Naphtho [1,2-c] furan-1,3-dione and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane- At least one member selected from the group consisting of the above-mentioned ranges.

The diamine used in the method (2) is the same as the diamine for synthesizing the polyamic acid as the polymer (A) in the present invention. A diamine having a carboxyl group; 4,4'-diaminodiphenyl ether, 4,4'-ethylenedianiline, (4-aminophenyl) -4-aminobenzoate, 4,4'-diaminodiphenylmethane and the above formula (DA1) At least one compound selected from the group consisting of the compounds shown; The content ratio of the aromatic diamine and the aromatic diamine containing the liquid crystal aligning group to the total diamine is also the same as in the above case.

The reaction of the tetracarboxylic acid diester or the tetracarboxylic acid diester dihalide with the diamine can be carried out in accordance with a known method.

The polyamic acid ester as the polymer (A) in the present invention may have only an amide ester structure, or may be a partial esterified product in which the amide structure and the amide ester structure coexist.

<(B) Polymer>

The (B) polymer contained in the liquid crystal aligning agent of the present invention is a polymer having a structure derived from a diamine having a tertiary nitrogen atom. The tertiary nitrogen atom in the polymer (B) may be present in the chain structure or in the cyclic structure.

The polymer (B) preferably does not have a structure derived from a diamine having a carboxyl group.

The (B) polymer is preferably at least one polymer selected from the group consisting of imidized polymers of polyamic acid and polyamic acid, and polyamic acid ester, although the requirements other than the above are not particularly limited.

With regard to the polymer (B), the above requirements for the polymer (A) are all proper, except that the requirements for the diamine used as the raw material are different. Therefore, in regard to the polymer (B), in the description of the polymer (A), it is also possible to substitute the description of the diamine with the following description, and further to the imidized polymer of the polyamic acid. Quot; diamine having a tertiary nitrogen atom &quot; in place of the &quot; diamine having a tertiary nitrogen atom &quot;.

[Diamine]

The diamine used for synthesizing the polymer (B) in the present invention includes a diamine having a tertiary nitrogen atom.

Examples of the diamine having a tertiary nitrogen atom include a compound represented by each of the following formulas (B1) and (B2), and it is preferable to use at least one selected from these compounds.

(Wherein (B1) of the X ¹ is a methylene group, a 2,2-propylene group, an alkylene group, an oxygen atom, an ester bond or an amide bond with a carbon number of 2 to 18,

n1 is 0 or 1;

In the case of two R's in the formula (B2), each R is independently an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms, preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, Particularly preferably an alkyl group having 1 carbon atom,

X ² is a methylene group, a 2,2-propylene group, an alkylene group having 2 to 12 carbon atoms, an allylene group having 6 to 18 carbon atoms, an oxygen atom, an ester bond or an amide bond,

n2 is 0 or 1, preferably 1).

Examples of the alkylene group represented by X ¹ in the formula (B1) include a 1,2-ethylene group, a 1,3-propylene group, a 1,4-butylene group, a 1,5-pentylene group, 1,7-pentylene group, 1,8-octylene group, n-dodecane-1,12-diyl group and the like. The number of carbon atoms of the X ¹ alkylene group is preferably 2 to 12, and more preferably 2 to 6. The ester bond and amide bond as X &lt; ¹ &gt; The two amino groups in the formula (B1) are preferably in the 4-position with respect to the other groups in the benzene ring to which the amino group is bonded.

Examples of the alkyl group of R in the formula (B2) include a methyl group, an ethyl group, a propyl group, a butyl group, and an octadecyl group. The alkyl group of R preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms. The aryl group of R may be unsubstituted or substituted. Examples of the substituent include an alkyl group having 1 to 4 carbon atoms, a halogen atom, a cyano group, and a hydroxyl group. Specific examples of such an aryl group include a phenyl group, a 4-methylphenyl group, a 4-fluorophenyl group, and a 4-cyanophenyl group.

As the alkylene group of X ^{2 in} the general formula (B2), the same alkyl groups as mentioned above as the alkylene group of X ^{1 in} the general formula (B1) can be exemplified. The number of carbon atoms of the alkylene group of X ² is preferably, 2 to 8. The allylene group as X ² may be unsubstituted or substituted. Examples of the substituent include an alkyl group having 1 to 4 carbon atoms, a halogen atom, a cyano group, and a hydroxyl group. Specific examples of such an allylene group include a 1,4-phenylene group, a 2-fluoro-1,4-phenylene group, a 2-cyano-1,4-phenylene group, .

Specific examples of the compound represented by the formula (B1) include compounds represented by the following formulas (B1-1) and (B1-2), respectively;

Specific examples of the compound represented by the formula (B2) include, for example, compounds represented by the following formulas (B2-1) and (B2-2), respectively, and at least one compound selected therefrom is used .

As the diamine used for synthesizing the polymer (B) in the present invention, only diamines having tertiary nitrogen atoms as described above may be used, and diamines other than the diamines having tertiary nitrogen atoms may be used in combination.

As other diamines that can be used herein, the same diamines as those described above can be used as other diamines used in the synthesis of the (A) polymer. However, it is preferable that the diamine does not contain a diamine having a carboxyl group.

The diamine used for synthesizing the polymer (B) in the present invention preferably contains 5 mol% or more, and preferably 5 mol% to 60 mol%, of the diamine having a tertiary nitrogen atom relative to the total diamine , More preferably 10 to 50 mol%. The diamine used for synthesizing the polyamic acid as the polymer (B) may be 4,4'-diaminodiphenyl ether, 4,4'-ethylenedianiline, (4-aminophenyl) -4-aminobenzoate, 4 , 4'-diaminodiphenylmethane, and a compound represented by the formula (DA1), and it is preferable that these structures have a structure derived from 5 To 95 mol%, and more preferably 10 to 90 mol%. The diamine used for synthesizing the polymer (B) preferably contains an aromatic diamine in an amount of 60 mol% or more, more preferably 80 mol% or more, relative to the total diamine. When the diamine having the tertiary nitrogen atom is an aromatic diamine, the diamine is also included in the numerical value. Examples of the diamine include 4,4'-diaminodiphenyl ether, 4,4'-ethylenedianiline, (4-aminophenyl ) -4-aminobenzoate, 4,4'-diaminodiphenylmethane, and a compound represented by the formula (DA1).

When the liquid crystal aligning agent of the present invention is applied to a TN type or STN type liquid crystal display device, the diamine used for synthesizing polyamic acid is preferably an aromatic diamine having a liquid crystal aligning group in an amount of not more than 20 mol% , More preferably in the range of 2 to 15 mol%, and particularly preferably in the range of 10 to 15 mol%. On the other hand, when the liquid crystal aligning agent of the present invention is applied to a liquid crystal display element of the IPS type or FFS type, the diamine used for synthesizing polyamic acid is preferably such that the ratio of the aromatic diamine having a liquid crystal aligning group to the total diamine, Is preferably in the range of 5 mol% or less, more preferably 3 mol% or less, and particularly preferably not.

<Solution viscosity and weight average molecular weight of (A) polymer and (B) polymer>

The imidized polymer and the polyamic acid ester of the polymer (A) or the polymer (B) of the polyamic acid and the polymer obtained as described above each have a concentration of 10 to 800 mPa · s And more preferably has a solution viscosity of 15 to 500 mPa 占 퐏. The solution viscosity (mPa 占 퐏) of the polymer is preferably 10 占 퐉 to 10 占 퐉, prepared using a good solvent (good solvent) of the polymer (e.g.,? -Butyrolactone, Measured at 25 캜 using an E-type rotational viscometer with respect to the weight% of the polymer solution.

The weight average molecular weight (Mw) of the polymer (A) and the polymer (B) in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably 500 to 100,000, and preferably 1,000 to 50,000 More preferable.

&Lt; Use ratio of polymer (A) and polymer (B) &gt;

The content of the (A) polymer and (B) polymer in the liquid crystal aligning agent of the present invention, (A) of the tertiary nitrogen atoms of the number of moles M _A and the (B) polymer of the carboxyl groups in the polymer the molar number ratio M _B M _a / M _B with a ratio in the range of 0.15 to 3.50. By having the ratio M _A / M _B of 0.15 or more, it is possible to prevent excitation by light of a non-covalent electron pair possessed by a tertiary nitrogen atom, and hence to suppress accumulation of DC charge by natural light or backlight irradiation. On the other hand, when the ratio M _A / M _B is 3.50 or less, a high voltage holding ratio is guaranteed and a voltage holding ratio is prevented from deteriorating over time. The ratio M _A / M _B is preferably 0.20 to 3.00.

<Other components>

The liquid crystal aligning agent of the present invention contains the polymer (A) and the polymer (B) as essential components and is preferably prepared as a solution-state composition dissolved and contained in an organic solvent to be described later, And may contain other components. Examples of such other components include (A) a polymer and (B) other polymer other than the polymer, a compound having at least one epoxy group in the molecule (hereinafter referred to as "epoxy compound"), a functional silane compound, And the like.

[Other Polymers]

The other polymer may be contained in the liquid crystal aligning agent of the present invention for the purpose of further improving the electrical characteristics of the obtained liquid crystal alignment film.

The other polymer in the present invention is a polymer not having any of a structure derived from a diamine having a carboxyl group and a structure derived from a diamine having a tertiary nitrogen atom and is preferably a polymer having an imidized polymer of polyamic acid or polyamic acid , Poly (amic acid) esters, polyesters, polyamides, polysiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly (styrene-phenylmaleimide) derivatives and poly (meth) acrylates. The other polymer is preferably a polymer having neither a structure derived from a diamine having a carboxyl group nor a structure derived from a diamine having a tertiary nitrogen atom as an imidized polymer of a polyamic acid or a polyamic acid, And at least one polymer selected from the group consisting of

The content of the other polymer in the liquid crystal aligning agent of the present invention is preferably 40% by weight or more based on the total amount of the polymer (hereinafter referred to as the total weight of the polymer (A), the polymer (B) By weight, and more preferably 20% by weight or less. Most preferably, the liquid crystal aligning agent of the present invention does not contain any other polymer.

[Epoxy Compound]

The epoxy compound can be compounded in the liquid crystal aligning agent of the present invention in order to improve the adhesiveness between the liquid crystal alignment film and the surface of the substrate, the electric characteristics of the liquid crystal alignment film, and the like.

The epoxy compound in the present invention is preferably a compound having at least two epoxy groups in the molecule, and examples thereof include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, Tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylol propane triglyceride N, N ', N'-tetraglycidyl-m-xylylene diamine, 1,3-bis (N, N N, N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N, N-diglycidyl-benzylamine, N , N-diglycidyl-aminomethylcyclohexane, N, N-diglycidyl-cyclohexylamine, and the like, 4 (International Publication No. 2009/096598) can be used as the polyorganosiloxane having an epoxy group.

When these epoxy compounds are compounded in the liquid crystal aligning agent, the blending ratio thereof is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the total amount of the polymers.

[Functional silane compound]

The functional silane compound can be used for the purpose of improving the printing property of the liquid crystal aligning agent. Examples of such a functional silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2 -Aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxy Silane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-triethoxysilylpropyl triethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 9-tri Methoxysilyl-3,6-diazanonyl acetate, methyl 9-trimethoxysilyl-3,6-diazanonanoate, N-benzyl-3-aminopropyltrimethoxysilane, Trimethoxysilane, glycidoxymethyltrimethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane and the like, Can.

When these functional silane compounds are compounded in the liquid crystal aligning agent, the blending ratio thereof is preferably 2 parts by weight or less, more preferably 0.02 to 0.2 parts by weight based on 100 parts by weight of the total of the polymers.

<Liquid Crystal Aligner>

The liquid crystal aligning agent of the present invention is constituted by dissolving the polymer (A), the polymer (B), and optionally other optional components optionally in an organic solvent.

Examples of the organic solvent used in the liquid crystal aligning agent of the present invention include N-methyl-2-pyrrolidone,? -Butyrolactone,? -Butyrolactam, N, N-dimethylformamide, Methylene-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxy propionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene Diethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether (ethylene glycol diethyl ether), ethylene glycol n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol- , Diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, di There may be used at least one selected from the group consisting of propylene glycol monomethyl ether, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, and propylene carbonate. .

A particularly preferable range of the solid concentration is different depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, in the case of the spinner method, the solid content concentration is particularly preferably in the range of 1.5 to 4.5% by weight. In the case of the printing method, it is particularly preferable that the solid concentration is in the range of 3 to 9 wt%, and the solution viscosity is in the range of 12 to 50 mPa · s accordingly. In the case of the ink-jet method, it is particularly preferable that the solid concentration is in the range of 1 to 5 wt%, and accordingly the solution viscosity is in the range of 3 to 15 mPa · s.

<Liquid Crystal Alignment Film and Liquid Crystal Display Device>

The liquid crystal alignment layer of the liquid crystal display device can be formed using the liquid crystal aligning agent of the present invention as described above.

The driving method of the liquid crystal display element to which the liquid crystal aligning agent of the present invention is applied is not particularly limited and liquid crystal display elements such as TN type, STN type, IPS type, FFS type, VA type, MVA type and PSA type Can be applied. However, since the liquid crystal display device of the present invention is excellent in rubbing resistance, it is preferable that the liquid crystal display device of the present invention is applied to liquid crystal display devices such as TN type, STN type, IPS type and FFS type which require a rubbing process for forming a liquid crystal alignment film, And is advantageous in that the effect of the present invention can be maximized.

The liquid crystal display element can be produced by using the liquid crystal aligning agent of the present invention, for example, through the following steps.

(1) Coating process (essential)

(2) Rubbing process (optional)

(3) Liquid crystal cell building process (essential)

(4) Polarizing plate bonding process (essential)

Hereinafter, each of the above steps will be described in order.

(1) Coating film formation process

In the coating film forming step, the liquid crystal alignment film of the present invention is applied to a substrate, and then the liquid crystal alignment film is heated to form a coating film on the substrate.

As a substrate, two substrates, each having or not having an electrode having the following constitution, are used as a pair by a driving method.

TN type, STN type, VA type, MVA type or PSA type: Two substrates each having a patterned transparent conductive film are used as a pair, and the formation surface of the transparent conductive film of each substrate is used as a coating surface.

IPS or FFS: a substrate on which a pair of electrodes made of a transparent conductive film or a metal film patterned in a comb shape and an opposing substrate on which no electrode is formed are used in a pair, And the one surface of the formation surface and the opposite substrate is a coated surface.

Examples of the material constituting the substrate include glass such as float glass and soda glass; Polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, poly (alicyclic olefin), and the like.

As the material constituting the transparent conductive film, for example, NESA film made of tin oxide (SnO ₂₎ (US PPG Company registered trademark), indium oxide - an ITO film or the like made of tin oxide (In ₂ O ₃ -SnO ₂₎ Can be used. In order to obtain the patterned transparent conductive film, for example, a method of forming a pattern by photo-etching after forming a transparent conductive film without a pattern, a method of using a mask having a desired pattern in forming a transparent conductive film, have.

Examples of the material constituting the metal film include chromium and the like.

A functional silane compound, a functional titanium compound or the like may be added to the film-forming surface of the substrate in order to improve the adhesion between the substrate surface and / or the transparent conductive film and the film prior to applying the liquid crystal aligning agent to the substrate. The pre-treatment for pre-coating may be carried out.

The liquid crystal aligning agent of the present invention is preferably applied on the application surface of such a substrate by an offset printing method, a spin coating method, a roll coating method, or an inkjet printing method. Pre-heating (pre-baking) is preferably carried out for the purpose of preventing the flow of the liquid of the applied alignment agent after application. The prebaking temperature is preferably 30 to 200 캜, more preferably 40 to 150 캜, particularly preferably 40 to 100 캜. The prebaking time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Thereafter, a firing (post-baking) process is carried out for the purpose of completely removing the solvent and for the purpose of thermally modifying the acid structure present in the polymer as required. The firing temperature (post-baking temperature) at this time is preferably 80 to 300 占 폚, more preferably 120 to 250 占 폚. The post baking time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes.

The film thickness of the film thus formed is preferably 0.001 to 1 占 퐉, and more preferably 0.005 to 0.5 占 퐉.

(2) Rubbing treatment process

This rubbing treatment step is optional depending on the driving method.

In the case of producing a liquid crystal display device of TN type, STN type, IPS type or FFS type, rubbing treatment is indispensable. On the other hand, in the case of producing a VA type liquid crystal display element, the film formed in the above step (1) can be directly used as a liquid crystal alignment film, but it is also possible to perform rubbing treatment arbitrarily. In the case of producing a PSA-type liquid crystal display element, the film formed in the above step (1) may be used as it is as the liquid crystal alignment film. However, for the purpose of controlling the inclination of the liquid crystal molecules and performing the orientation division in a simple manner, A rubbing treatment of strength may be performed.

The rubbing treatment can be carried out by rubbing the coating film in a predetermined direction by using, for example, a roll in which a cloth made of fibers such as nylon, rayon, and cotton is wound.

The coating film formed of the liquid crystal aligning agent of the present invention has excellent rubbing resistance, so that it is possible to perform a desired rubbing treatment, thereby giving a strong liquid crystal aligning property to the coating film.

(3) Liquid crystal cell building process

When a liquid crystal display device of a TN type, an STN type, an IPS type, an FFS type or a VA type is manufactured, a pair of substrates on which a liquid crystal alignment film is formed as described above is placed in a gap opposed to the liquid crystal alignment film, The liquid crystal cell can be manufactured. On the other hand, in the case of manufacturing a PSA type liquid crystal display device, a liquid crystal cell can be manufactured by disposing a liquid crystal composition containing liquid crystal and photopolymerizable compound in a gap between a pair of substrates.

In order to arrange the liquid crystal or the liquid crystal composition in the gap between the substrates, for example, the following method can be used;

First method: A liquid crystal or a liquid crystal composition is injected and filled in a cell gap partitioned by a liquid crystal alignment film surface and a sealing material after a periphery of a pair of substrates opposed to each other so as to face the liquid crystal alignment film is bonded by a sealing material, Followed by sealing the pores, or

Second Method: A sealing material having an ultraviolet curing property, for example, is applied to a predetermined position on one of the pair of substrates (two substrates) on which the liquid crystal alignment film is formed, Or the liquid crystal composition is dropped and then the other substrate is bonded and pushed so that the liquid crystal alignment film is opposed to spread the liquid crystal or the liquid crystal composition on the entire surface of the substrate and then the ultraviolet light is irradiated to the entire surface of the substrate to cure the sealing material (ODF (One Drop Fill) method).

In any of the above-described methods, the liquid crystal cell manufactured as described above is further heated to a temperature at which the liquid crystal used has an isotropic phase (isotropic phase), and then gradually cooled to room temperature to obtain a flow It is preferable to remove the orientation.

Examples of the liquid crystal arranged in the cell gap in the above are nematic liquid crystal and smectic liquid crystal. Of these, nematic liquid crystals are preferable, and examples thereof include liquid crystal such as cypher base liquid crystal, agar liquid crystal, biphenyl liquid crystal, phenyl cyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane liquid crystal, Based liquid crystal, a dioxane-based liquid crystal, a bicyclooctane-based liquid crystal, a quartz-based liquid crystal, and the like can be preferably used. Further, to these liquid crystals, for example, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonanoate and cholesteryl carbonate; Chiral agents such as those sold under the trade names "C-15" and "CB-15" (Merck); p-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate, and the like may be added and used. As the nematic liquid crystal, a liquid crystal (collectively referred to as a positive liquid crystal) in which the dielectric constant is expressed in the major axis direction of the liquid crystal molecule or a liquid crystal (collectively referred to as a negative liquid crystal) in which the dielectric constant is expressed in the minor axis direction of the liquid crystal molecule, Particularly, a negative type liquid crystal is particularly preferable. Normally, when a negative type liquid crystal is used, the voltage holding ratio is largely lowered. However, by using the liquid crystal aligning agent of the present invention, a decrease in the voltage holding ratio can be suppressed. Further, when the liquid crystal aligning agent of the present invention is used, the voltage holding ratio at the time of application of the negative type liquid crystal can be improved without deteriorating rubbing resistance and residual voltage characteristics.

In the case of manufacturing a PSA type liquid crystal display device, thereafter, a voltage is applied between the conductive films included in the pair of substrates to irradiate the liquid crystal cell with the liquid crystal activated. The voltage to be applied here may be DC or AC of 5 to 50 V, for example. As the light to be irradiated, for example, ultraviolet rays and / or visible rays including light having a wavelength of 150 to 800 nm can be used, but ultraviolet rays including light having a wavelength of 300 to 400 nm are preferable. As the light source of the irradiation light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp and an excimer laser can be used. The ultraviolet ray in the above-mentioned preferable wavelength range can be obtained by a means for using the light source together with, for example, a filter diffraction grating or the like. The dose of light is preferably 1,000 J / m 2 or more and less than 200,000 J / m 2, and more preferably 1,000 to 100,000 J / m 2.

(4) Polarizing plate bonding process

Then, the liquid crystal display element of the present invention can be obtained by bonding a polarizing plate to the outer surface of the liquid crystal cell constructed above. As a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing plate called a "H film" in which iodine is dielectrically absorbed while polyvinyl alcohol is oriented in a stretched state, a polarizing plate sandwiching a cellulose acetate protective film or a polarizing plate made of the H film itself . When the coating film is subjected to the rubbing treatment, the two substrates are opposed to each other such that the rubbing directions of the coating films are at a predetermined angle, for example, orthogonal or anti-parallel to each other.

(Example)

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

&Lt; Synthesis of Polymer &

Synthesis Examples A1 to A4, B1 to B4 and Comparative Synthesis Examples C1 to C3

(A) polymers (Synthesis Examples A1 to A4), (B) polymers (Synthesis Examples B1 to B4), and other polymers (Comparative Synthesis Examples C1 to C3) were synthesized.

A tetracarboxylic acid dianhydride and diamine shown in Table 1 were put into a four-necked flask equipped with a stirrer and a nitrogen inlet tube at the ratios (mol%) shown in Table 1, respectively, (NMP: BL = 50: 50 (weight ratio)) consisting of N-methylpyrrolidone (NMP) and? -Butyrolactone (BL) was added to the solution to prepare a solution having a monomer concentration of 15.0 wt% The reaction was carried out with stirring for a time to obtain a polymer solution containing each of polyamic acids A1 to A4, B1 to B4 and C1 to C3 having a polymer concentration of about 15%.

The solution viscosity of each polymer solution measured at 25 캜 using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) is also shown in Table 1.

The abbreviations of the monomers in Table 1 are as follows.

[Tetracarboxylic acid dianhydride]

CB: 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride

PMDA: pyromellitic acid dianhydride

ODPA: 4,4'-oxydiphthalic acid dianhydride

CHDA: 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride (trans form)

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

TDA: 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [ - Dion

BODA: 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-2 anhydride

[Diamine]

- diamine having a carboxy group -

3,5-DAB: 3,5-diaminobenzoic acid

2,5-DAB: 2,5-diaminobenzoic acid

A diamine having a -3-nitrogen atom,

BISP: Compound represented by the above formula (B1-1)

APPC: The compound represented by the above formula (B1-2)

DABZm: Compound represented by the above formula (B2-1)

DATA: Compound represented by the formula (B2-2)

- Other diamines -

BAAB: 4-aminobenzoic acid 4-aminophenyl

ETDA: 1,2-bis (4-aminophenyl) ethylene

DDE: 4,4'-diaminodiphenyl ether

DEGDA: 4,4 '- [oxybis (1,2-ethyleneoxy)] bis (aniline)

DDM: 4,4'-diaminodiphenylmethane

DA1: Compound represented by the above formula (DA1)

&Lt; Preparation and evaluation of liquid crystal aligning agent &gt;

Example 1

I. Preparation of liquid crystal aligning agent

133 parts by weight of the solution containing the polyamic acid A1 obtained in Synthesis Example A1 (20 parts by weight of polyamic acid A1 conversion) and 533 parts by weight of the solution containing polyamic acid B1 (80 parts by weight of polyamic acid A1 equivalent) , NMP, BL and butyl cellosolve (BC) were added to prepare a solution having a solvent composition of NMP: BL: BC = 40: 40: 20 (weight ratio) and a polymer concentration of 4 wt% .

Ⅱ. Evaluation of liquid crystal aligning agent

(1) Evaluation of storage stability

250 mL of the liquid crystal aligning agent prepared in the above was stored under an environment of -15 캜 and after initial (after preparation), 2 weeks after, 4 (using a particle counter "KL-11A" (Number of particles / 1 mL) having a particle diameter of 1.0 占 퐉 or more after the day, after the week, after the week, after the week, and after the week.

The number of foreign substances in each measurement is shown in Table 2.

(2) Evaluation of rubbing resistance

The "I. Preparation of liquid crystal aligning agent "was spin-coated on ITO surface of a glass substrate with an ITO electrode having a length of 3 cm and a width of 4.5 cm and was prebaked at 70 ° C for 80 seconds, Post baking was performed for 20 minutes in an oven to form a film having a thickness of 100 nm on the ITO surface of the substrate. This rubbing treatment was carried out for 20 times under the conditions of a rotation speed of 1,000 rpm, a roll advancing speed of 20 mm / min, and a pore press-in amount of 0.4 mm using a rubbing device wrapping a cotton cloth on a roll having a diameter of 120 mm. As apparent from comparison with the rubbing condition in the following "(3) Production of liquid crystal cell", this condition is a more severe acceleration test than usual.

The surface of the coated film after the rubbing treatment under the above conditions was observed by an optical microscope to examine the presence or absence of the peeling of the coated film on the surface of the coated film,

When no peeling material was observed: rubbing resistance &quot; good &quot;

When the exfoliation is observed very slightly: the rubbing resistance is "possible"

When a lot of peelings are observed: rubbing resistance "bad"

(3) Production of liquid crystal cell

The "I. Preparation of liquid crystal aligning agent "was applied on the ITO surface of a glass substrate with an ITO electrode having a length of 3 cm x 4.5 cm in width under the same conditions as in the above (2) Evaluation of rubbing resistance, Prebaking and post baking were performed to form a film having a thickness of 100 nm on the ITO surface of the substrate. This coating was subjected to rubbing treatment under the conditions of a rotation number of 1,000 rpm, a roll advancing speed of 20 mm / min, and a pore pressure of 0.4 mm using the same rubbing apparatus as in "(2) Evaluation of rubbing resistance" Thereby giving a liquid crystal alignment film.

Two substrates (one pair) having a liquid crystal alignment film on the ITO surface were prepared as described above.

A bead spacer having a diameter of 3.5 mu m was scattered on the surface of the liquid crystal alignment film of one of the substrates, and then a sealing material was printed on the outer periphery of the liquid crystal alignment film. Subsequently, another substrate was bonded to the liquid crystal alignment film surface so that the liquid crystal alignment film surface was inward and the rubbing direction was reversed, and then the substrate was cured by heating in an oven adjusted to 150 DEG C for 1 hour to form an empty cell . Thereafter, liquid crystal MLC-7028-100 (trade name, manufactured by Merck Ltd., positive liquid crystal) or MLC-7026-100 (trade name, manufactured by Merck Ltd., negative liquid crystal) was injected into the gap of the obtained blank cell by a low pressure injection method To prepare a nematic liquid crystal cell of antiparallel alignment.

(4) Evaluation of residual voltage relaxation

A direct current voltage of 5 V was applied to the liquid crystal cell prepared above for 5 minutes, a short circuit was made for 1 second after the application was canceled, and the residual voltage in the cell was measured for 1,200 seconds. For the measurement, a liquid crystal physical property evaluation device "Model 6254" manufactured by TOYO TECHNICAL CO., LTD. Was used.

Table 2 shows the residual voltages in the cells after 100 seconds and 200 seconds at this time.

(5) Evaluation of Voltage Conservation Rate

Using the liquid crystal cell prepared above, the voltage holding ratio was calculated by applying a direct current voltage of 5 V for 100 microseconds and measuring a change in voltage from 167 milliseconds after the application was canceled. For the measurement, a liquid crystal physical property evaluation device "Model 6254" manufactured by TOYO TECHNICAL CO., LTD. Was used.

Examples 2 to 6 and Comparative Examples 1 to 5

&Quot; I. &quot; A liquid crystal aligning agent was prepared and evaluated in the same manner as in Example 1 except that the type and amount of the polyamic acid contained in the polymer solution used were changed as shown in Table 2 .

The evaluation results are shown in Table 2.

The numerical values in parentheses in the column "M _A / M _B " in Comparative Examples 1, 2 and 5 in Table 2 indicate the number of moles of carboxyl groups in the other polymer used in these Comparative Examples and the number of moles of tertiary nitrogen atoms It is rain.

Claims (7)

(A) a polymer having a structure derived from a diamine having a carboxyl group,
(B) a polymer having a structure derived from a diamine having a tertiary nitrogen atom, and
The (A) liquid crystal alignment, characterized in that the number of moles of carboxyl groups in the polymer and the M _A (B) the number of moles of a tertiary nitrogen atom in the polymer of the non-M _A / M _B is from 0.15 to 3.50 with the _B M . The method according to claim 1,
Wherein the diamine having a tertiary nitrogen atom is at least one selected from the compounds represented by the following formulas (B1) and (B2)

(Wherein (B1) of the X ¹ is a methylene group, a 2,2-propylene group, an alkylene group, an oxygen atom, an ester bond or an amide bond with a carbon number of 2 to 18,
n1 is 0 or 1;
When two R's in the formula (B2) are each independently an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms,
X ² is a methylene group, a 2,2-propylene group, an alkylene group having 2 to 12 carbon atoms, an allylene group having 6 to 18 carbon atoms, an oxygen atom, an ester bond or an amide bond,
n2 is 0 or 1). The method according to claim 1,
Wherein the polymer (A) and the polymer (B) are each independently at least one polymer selected from the group consisting of polyamic acid, imidized polymer of polyamic acid and polyamic acid ester. The method of claim 3,
The polymer (A) and the polymer (B)
Pyromellitic dianhydride, 4,4'-oxydiphthalic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 2, , 3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) 1,2-c] furan-1,3-dione and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-2 anhydride. A liquid crystal aligning agent which is a polymer further having a structure derived from one kind of compound. The method of claim 3,
The polymer (A) and the polymer (B)
4,4'-diaminodiphenyl ether, 4,4'-ethylenedianiline, (4-aminophenyl) -4-aminobenzoate, 4,4'-diaminodiphenylmethane and the following formula Wherein the liquid crystal aligning agent further has a structure derived from at least one compound selected from the group consisting of compounds represented by the following formulas.

A liquid crystal alignment film formed by the liquid crystal aligning agent according to any one of claims 1 to 5. A liquid crystal display element comprising the liquid crystal alignment film according to claim 6.