KR20190045231A - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element using same - Google Patents

Abstract

Disclosed is a liquid crystal aligning agent capable of forming a liquid crystal alignment film having excellent electric characteristics in terms of emission of accumulated charges and the like and which is not colored but has transparency. At least one polymer selected from the group consisting of a polyamic acid obtained by reacting a diamine component having a structure of the formula [1] with a diamine component containing a tetracarboxylic acid dianhydride component, and a polyimide obtained by imidizing the polyamic acid Wherein the liquid crystal aligning agent is a liquid crystal aligning agent. (A represents a thermal decomposable group which is substituted with a hydrogen atom by heating at a temperature of 150 to 300 DEG C. The hydrogen atom of the benzene ring may be substituted with an alkyl group or an alkoxy group having 1 to 5 carbon atoms or a halogen group. * Indicates a combined hand.)

Description

Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element using same

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film using the liquid crystal aligning agent, and a liquid crystal display element.

The liquid crystal alignment film is a constituent member of a liquid crystal display element widely used as a display device, and plays a role of aligning the liquid crystal in a certain direction. At present, the main liquid crystal alignment film which is industrially used is formed of a liquid crystal aligning agent composed of polyimide precursor polyamic acid (also referred to as polyamide acid) or polyimide solution. Specifically, it is obtained by applying a liquid crystal aligning agent to a substrate, and heating and firing the liquid crystal aligning agent, followed by liquid crystal alignment treatment.

Conventionally, in the liquid crystal alignment treatment, the surface treatment is mainly carried out by rubbing. However, in the rubbing treatment, it is usually difficult to carry out a highly uniform alignment treatment, resulting in defective orientation of the liquid crystal or deficiency of the liquid crystal alignment film, Display defects may occur, or dust may be generated. In recent years, there has been a tendency that the area of the substrate is enlarged and the irregularity becomes larger due to enlargement of the substrate used for the panel, higher definition, lower cost, etc. In the case of forming the alignment film on such a substrate, Leaving behind.

On the other hand, as an orientation treatment method instead of the rubbing method, an orientation treatment using a photoreaction has been proposed. Specifically, a method of forming a film of a polymer having a specific site causing a photoreaction such as polyvinyl cinnamate on the surface of a substrate and irradiating polarized or unpolarized radiation to give a liquid crystal aligning ability (photo alignment method) It is known. According to this method, it is possible to realize uniform liquid crystal alignment without generating static electricity or dust, and it is also possible to improve the viewing angle by orientation division (see Patent Documents 1 and 2).

In a liquid crystal cell such as TN (Twisted Nematic) or STN (Super Twisted Nematic), it is necessary for the liquid crystal alignment film to have a function of tilting the liquid crystal molecules at a predetermined angle (pretilt angle) with respect to the substrate surface. In order to develop a pretilt angle, there is known a liquid crystal alignment film using polyamic acid or polyimide having alkyl side chains, side chains of steroid skeleton, side chains having a ring structure, and the like (Patent Documents 3, 4 and 5). In the alignment treatment using light, the pretilt angle is usually given by irradiating the radiation incidence direction to the substrate surface with respect to the substrate normal direction (see Patent Document 1).

Japanese Patent Application Laid-Open No. 6-287453 Japanese Patent Application Laid-Open No. 9-297313 Japanese Laid-Open Patent Publication No. 05-043687 Japanese Laid-Open Patent Publication No. 04-281427 Japanese Patent Application Laid-Open No. 02-223916

As described above, conventionally, the main liquid crystal alignment film is formed by a liquid crystal aligning agent comprising a solution of polyamic acid or polyimide, which is a polyimide precursor. However, such a liquid crystal aligning agent has recently been widely used as a substrate for a panel, , There are various problems due to low cost and the like, and there is room for improvement. In order to solve one of these problems, a polyamic acid obtained by reacting a diamine represented by the following formula (DA-3) as a raw material with a tetracarboxylic acid dianhydride component and / or a polyamic acid obtained by imidizing the polyamic acid A liquid crystal aligning agent containing a polyimide obtained by the above method.

[Chemical Formula 1]

A liquid crystal display device having a liquid crystal alignment film obtained from such a liquid crystal aligning agent has excellent properties in terms of electrical characteristics (such as the emission of accumulated charges). On the other hand, when such a liquid crystal aligning agent is used, it has been found that the resulting liquid crystal alignment film tends to be colored blackish brown and loses its transparency, and consequently adversely affects the liquid crystal alignment element having the liquid crystal alignment film.

The present invention is to provide a liquid crystal alignment film which is excellent in the properties of a polyamic acid as a polymer contained in a liquid crystal aligning agent and which can be obtained by using the above-mentioned diamine compound, It is an object of the present invention to provide a liquid crystal aligning agent without adversely affecting the liquid crystal aligning element.

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and as a result, the present invention has been completed.

The present invention relates to a polyimide obtained by reacting a diamine component containing a diamine having a structure represented by the following formula [1] with a tetracarboxylic acid dianhydride component, and a polyimide obtained by imidizing the polyamic acid And at least one polymer selected from the group consisting of

(2)

(Wherein A represents a thermally-cleavable group which is substituted with a hydrogen atom by heating at a temperature of 150 to 300 DEG C. The hydrogen atom of the benzene ring is preferably an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, And may be substituted by a halogen group.

The liquid crystal aligning agent of the present invention is characterized in that it contains polyamic acid derived from a diamine (hereinafter also referred to as a specific diamine) represented by the formula [1] and / or polyimide obtained by imidizing the polyamic acid Such a polymer has a high solubility in a polar solvent such as N-methylpyrrolidone (NMP) and has good handling during polymerization. The liquid crystal aligning agent containing such a polymer has excellent coating and film forming properties A liquid crystal alignment film in which the decrease in the voltage holding ratio is suppressed even when exposed to light irradiation can be obtained.

In addition, the liquid crystal aligning agent of the present invention is characterized in that a liquid crystal alignment layer obtained by using a polyamic acid or a polyimide containing the following diamine compound (DA-3) having a similar structure to a specific amine, , A liquid crystal alignment film which is not colored blackish brown and has transparency and does not adversely affect the liquid crystal display element can be formed.

Whether or not the liquid crystal aligning agent of the present invention achieves such excellent effects can be estimated as follows. Namely, the diamine of the formula (DA-3) having a similar structure of the diphenylamine skeleton as the specific diamine has a secondary amino group more reactive than the primary amino group in its structure, Reacts with a tetracarboxylic acid dianhydride component to obtain a polyamic acid, and causes an undesirable three-dimensional reaction. As a result, it is considered that the resulting reactant causes a coloring phenomenon and lowers the properties as a liquid crystal aligning agent.

On the other hand, the specific diamine of the present invention has a secondary amino group which is rich in reactivity in the same structure as the above-mentioned formula (DA-3). Since the secondary amino group is protected by a thermal degital component, In the course of the reaction with the tetracarboxylic acid dianhydride component to obtain the compound of the present invention does not cause an undesirable three-dimensional reaction and consequently does not cause a coloring phenomenon and does not degrade the properties as a liquid crystal aligning agent.

In the liquid crystal aligning agent of the present invention, the contained polyamic acid or polyimide has an amino group protected by a thermally cleavable group, but the amino group protected by the thermally cleavable group is a liquid crystal aligning agent Can be changed to a deprotected amino group by heating in a firing step in the process of applying the substrate to a substrate and firing to form a liquid crystal alignment film.

The deprotected amino group is reacted again to react and the amino group generated by the elimination is reacted in the molecule to form a heterocyclic ring or the like to produce a rigid side chain so that the side chain structure has a good pretilt angle As a triggering site. In addition, all the amino groups from which the thermally cleavable group is removed are not used for the cyclization reaction, and some of them are also used for intermolecular reaction, thereby contributing to improvement of the film strength and improvement of reliability by crosslinking with low molecular components in the polymer do.

In this way, the polyamic acid or polyimide using the specific diamine of the present invention does not easily shrink at the time of rubbing treatment, and even when exposed to a long period of high temperature, backlight irradiation, etc., It does not happen.

≪ Specific diamine of the present invention &

The diamine used as a raw material for the liquid crystal aligning agent of the present invention is a diamine having a structure represented by the following formula [1].

(3)

In the above formula [1], A is a thermal degassing group which is substituted with hydrogen by heating at 150 to 300 캜, which is the baking temperature of the liquid crystal aligning agent of the present invention. The thermal degreasing agent is desirably desorbed at 170 to 300 占 폚, particularly preferably at 180 to 250 占 폚. * Indicates a combined hand.

Examples of thermal degreasing agents include carbamate-based organic groups such as benzyloxycarbonyl, 9-fluorenylmethyloxycarbonyl, allyloxycarbonyl, tertiary butoxycarbonyl (also referred to as Boc). Particularly preferred is a Boc group or a 9-fluorenylmethoxycarbonyl group since it has a good efficiency of elimination, is a relatively low temperature and is harmless to the elimination.

The hydrogen atom of the benzene ring in the formula [1] may be optionally substituted with an alkyl group or an alkoxy group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, or a halogen group such as chlorine, bromine or fluorine .

The amino group of the specific diamine is preferably a primary amino group. The secondary amino group may be substituted with an alkyl group having a relatively small molecular weight such as methyl, ethyl, propyl or butyl.

Preferable specific examples of the specific diamine include, but are not limited to, the following. Boc in the formula represents a tert-butoxycarbonyl group.

[Chemical Formula 4]

≪ Tetracarboxylic acid dianhydride component >

In order to obtain the polyimide precursor of the present invention, a tetracarboxylic acid dianhydride (also referred to as a specific tetracarboxylic acid dianhydride) represented by the following formula [7] is preferably used as a part of the tetracarboxylic acid dianhydride component .

[Chemical Formula 5]

In the formula [7], Z ₁ is a tetravalent organic group having 4 to 13 carbon atoms and further has an aromatic cyclic hydrocarbon group. Specifically, the group represented by any one of formulas [7a] to [7k] is preferable.

[Chemical Formula 6]

In formula [7], a preferable group of Z ₁ is a group represented by formula [7a] or formula [7g] from the viewpoint of polymerization reactivity and ease of synthesis. Among them, formula [7a] is most preferable.

When a tetracarboxylic acid dianhydride having the structure of the formula [7a] is used, it is preferably 20 mass% or more, more preferably 30 mass% or more, of the total amount of the tetracarboxylic acid dianhydride components. All of the tetracarboxylic acid components used in the production of the polyimide precursor may be a tetracarboxylic acid dianhydride having the structure of the formula [7a].

In the present invention, an aliphatic tetracarboxylic acid dianhydride other than the specific tetracarboxylic acid dianhydride and other tetracarboxylic acid components may be used.

The aliphatic tetracarboxylic acid dianhydride includes, for example, 1,2,3,4-butanetetracarboxylic acid dianhydride. Examples of the alicyclic tetracarboxylic acid dianhydride include 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,2,3,4-tetramethyl-1,2,3, 4-cyclobutanetetracarboxylic acid dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutane Tetracarboxylic acid dianhydride, 1,3-diphenyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 1, 2,4,5-cyclohexanetetracarboxylic acid dianhydride, 1,2,3,4-cycloheptanetetracarboxylic acid dianhydride, 2,3,4,5-tetrahydrofuran tetracarboxylic acid dianhydride, Cyclohexylsuccinic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene Succinic dianhydride, bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic acid dianhydride, bicyclo [4, 3,0] nonane-2,4,7,9-tetracarboxylic acid dianhydride, bicyclo [4,4,0] decane-2,4,7,9-tetracarboxylic acid dianhydride, bicyclo [ 4,4,0] decane-2,4,8,10-tetracarboxylic acid dianhydride, tricyclo [6.3.0.0 <2,6>] undecane-3,5,9,11-tetracarboxylic acid 2-anhydride, 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid dianhydride, bicyclo [ , 2] octo-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl- -Dicarboxylic acid dianhydride, tetracyclo [6,2,1,1,0,2,7] dodeca-4,5,9,10-tetracarboxylic acid dianhydride, 3,5,6-tri Carboxynorbornane-2: 3,5: 6 dicarboxylic acid dianhydride, and the like.

Examples of the other tetracarboxylic acid component include tetracarboxylic acid, tetracarboxylic acid dihalide, tetracarboxylic acid dianhydride, an ester obtained by dialkyl esterifying the carboxylic acid group of tetracarboxylic acid, a tetracarboxylic acid dihalide , And the like, and dialkyl esterified esterified carboxylic acid groups.

The above other tetracarboxylic acid component may be used alone or in combination of two or more thereof in consideration of the properties of the liquid crystal alignment film to be formed in consideration of liquid crystal aligning property, voltage holding property, and accumulated charge.

&Lt; Polymer of the present invention &

The polymer in the present invention means a polyimide obtained by imidizing a polyamic acid and / or a polyamic acid thereof.

<Polyamic acid>

The polyamic acid of the present invention is obtained by the reaction of a diamine component containing a specific diamine and a tetracarboxylic acid dianhydride component.

The content of the specific diamine in the diamine component for obtaining the polyamic acid by the reaction with the tetracarboxylic acid dianhydride component is not limited. The content of the specific diamine in the diamine component may be 100%. However, various diamines can be used in combination in order to satisfy various properties required for the liquid crystal alignment film, for example, a property of increasing the pretilt angle of the liquid crystal and a property of increasing the vertical alignment of the liquid crystal . Therefore, the content of the specific diamine in the diamine component used for the polymerization is preferably 1 to 50 mol%, particularly preferably 5 to 30 mol%.

Examples of the diamines other than the specific diamine (hereinafter, also referred to as other diamines) used in combination with the diamine component in the case where the specific diamine is less than 100 mol% include alicyclic diamines, aromatic-aliphatic diamines, heterocyclic diamines, aliphatic Diamine and the like.

Examples of the alicyclic diamine include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'- Dimethyldicyclohexylamine, isophoronediamine, and the like.

Examples of the aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, , 4-diamino-2-methoxybenzene, 2,5-diamino-p-xylene, 1,3-diamino-4-chlorobenzene, 3,5-diaminobenzoic acid, Dichlorobenzene, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-2,2'-dimethylbibenzyl, 4,4'-diaminodiphenyl Methane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 2,2'-diaminostyrene Benzene, 4,4'-diaminostilbene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4 ' Diaminodiphenylsulfone, 4,3'-diaminodiphenylsulfone, 4,4'-diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3- Aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,5-bis Benzoic acid, 4,4'-bis (4-aminophenoxy) bibenzyl, 2,2-bis [ Bis [4- (4-aminophenoxy) phenyl] propane, bis [4- Bis (4-aminophenyl) phenyl] sulfone, 1,1-bis (4-aminophenyl) cyclohexane, 4-aminophenyl) fluorene, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2- , 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrrene, 1,6-diamino Pyrene, 1,8-diaminopyrene, 2,7-diaminofluorene, 1,3-bis (4-aminophenyl) tetramethyldisiloxane, benzidine, 2,2'-dimethylbenzidine, (4-aminophenyl) ethane, 1,3-bis (4- Bis (4-aminophenyl) pentane, 1,6-bis (4-aminophenyl) hexane, 1,7-bis Bis (4-aminophenyl) decane, 1,1-bis (4-aminophenyl) decane, Bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) Hexane, 1,7-bis (4-aminophenoxy) heptane, 1,8-bis (4-aminophenoxy) octane, (4-aminophenoxy) decane, di (4-aminophenyl) propane-1,3-dioate, , Di (4-aminophenyl) hexane-1,6-dioate, di (4-aminophenyl) heptane-1,7-dioate, di -Dioate, di (4-aminophenyl) nonane-1,9-dioate, di (4-aminophenyl) decane- Bis [4- (4-aminophenoxy) phenoxy] butane, 1,5-bis [4- (4-aminophenoxy) phenoxy] pentane, 1,6-bis [4- (4-aminophenoxy) phenoxy] Heptane, 1,8-bis [4- (4-aminophenoxy) phenoxy] octane, 1,9- (4-aminophenoxy) phenoxy] decane, and the like.

Examples of aromatic-aliphatic diamines include 3-aminobenzylamine, 4-aminobenzylamine, 3-amino-N-methylbenzylamine, 4-amino-N-methylbenzylamine, Amino-N-methylphenethylamine, 3- (3-aminopropyl) aniline, 4- (3-aminopropyl) aniline, 3- 4- (4-aminobutyl) aniline, 3- (4-methylaminobutyl) aniline, 4- 3- (5-methylaminopentyl) aniline, 4- (5-methylaminopentyl) aniline, Aniline, 2- (6-aminonaphthyl) methylamine, 3- (6-aminonaphthyl) methylamine, 2- .

Examples of the heterocyclic diamine include 2,6-diaminopyridine, 2,4-diaminopyridine, 2,4-diamino-1,3,5-triazine, 2,7-diaminodibenzofuran, Diaminocarbazole, 2,4-diamino-6-isopropyl-1,3,5-triazine, 2,5-bis (4-aminophenyl) -1,3,4-oxadiazole Sol and the like.

Examples of the aliphatic diamine include 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, Diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,3-diamino-2,2-dimethylpropane, 1,6- 2,5-dimethylhexane, 1,7-diamino-2,5-dimethylheptane, 1,7-diamino-4,4-dimethylheptane, 1,7-diamino- Diamino-5-methylheptane, 1,12-diaminododecane, 1,18-diaminooctadecane, 1,2-bis (3-aminopropoxy) ethane and the like.

A diamine compound having an alkyl group, a fluorine-containing alkyl group, an aromatic ring, an aliphatic ring, a heterocyclic ring, or a substituent having a pericyclic substituent may be used in combination in the side chain. Specifically, diamines represented by the following formulas [DA1] to [DA26] are exemplified.

(7)

(R &lt; ₆ &gt; is an alkyl group or a fluorine-containing alkyl group having 1 to 22 carbon atoms)

[Chemical Formula 8]

(S ₅ represents -COO-, -OCO-, -CONH-, -NHCO-, -CH ₂ -, -O-, -CO-, or -NH-, and R ₆ represents a group having 1 to 22 carbon atoms , An alkyl group or a fluorine-containing alkyl group)

[Chemical Formula 9]

(S ₆ represents -O-, -OCH ₂ -, -CH ₂ O-, -COOCH ₂ -, or -CH ₂ OCO-, R ₇ represents an alkyl group, an alkoxy group, a fluorine Containing alkyl group or a fluorine-containing alkoxy group)

[Chemical formula 10]

(S ₇ represents -COO-, -OCO-, -CONH-, -NHCO-, -COOCH ₂ -, -CH ₂ OCO-, -CH ₂ O-, -OCH ₂ -, or -CH ₂ - , R ₈ is an alkyl group, an alkoxy group, a fluorine-containing alkyl group or a fluorine-containing alkoxy group having 1 to 22 carbon atoms)

(11)

(S ₈ represents -COO-, -OCO-, -CONH-, -NHCO-, -COOCH ₂ -, -CH ₂ OCO-, -CH ₂ O-, -OCH ₂ -, -CH ₂ -, -O -, or -NH-, and R ₉ represents a fluorine group, a cyano group, a trifluoromethane group, a nitro group, an azo group, a formyl group, an acetyl group, an acetoxy group, or a hydroxyl group)

[Chemical Formula 12]

[Chemical Formula 13]

(Wherein R ₁₀ is an alkyl group having 3 to 12 carbon atoms and the cis trans isomer of 1,4-cyclohexylene is a trans-isomer)

[Chemical Formula 14]

[Chemical Formula 15]

[Chemical Formula 16]

In the case of orienting by light, it is preferable to use a specific diamine in combination with diamines of [DA-1] to [DA-26] to obtain a more stable pretilt angle. More preferred diamines that can be used in combination are diazines of the formula [DA-10] to [DA-26], and more preferably diamines of the [DA-10] to the [DA-16]. The preferred content of these diamines is not particularly limited, but is preferably 5 to 50 mol% of the diamine component, and is preferably 5 to 30 mol% in terms of printability.

In addition, the following diamines may be used in combination.

[Chemical Formula 17]

(m is an integer of 0 to 3, and in the formula [DA-34], n is an integer of 1 to 5).

The diamine of the formula [DA-29] to [DA-34] can improve the voltage holding property when the liquid crystal alignment film is formed by containing diamines such as the formula [DA- It is effective in reducing accumulation telephone.

The diaminosiloxane represented by the following formula [DA-35] and the like may also be mentioned as other diamines.

[Chemical Formula 18]

(m is an integer of 1 to 10)

The other diamines may be used alone or in combination of two or more thereof depending on the properties such as liquid crystal aligning property, voltage holding property, and accumulated charge when the liquid crystal alignment film is used.

&Lt; Preparation of polyamic acid &

As a method for obtaining the polyamic acid of the present invention by the reaction of the tetracarboxylic acid dianhydride component and the diamine component, a known method may be used. Generally, the tetracarboxylic acid dianhydride component and the diamine component are reacted in an organic solvent. The reaction of the tetracarboxylic acid dianhydride component and the diamine is advantageous in that it proceeds relatively easily in an organic solvent and does not generate any by-products.

The organic solvent used for the reaction of the tetracarboxylic acid dianhydride component and the diamine is not limited as far as the produced polyamic acid is dissolved. Specific examples thereof are given below.

N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, But are not limited to, pyridine, dimethyl sulfone, hexamethyl sulfoxide,? -Butyrolactone, isopropyl alcohol, methoxymethyl pentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, Ketones, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol mono Butyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol mono Diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene Glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, But are not limited to, acetate, butylbutyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, Propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, Methoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid, 3-ethoxypropionic acid, 3- Methoxy-N, N-dimethylpropanamide, 3-ethoxy-N, N-dimethylacetamide, propyl methoxypropionate, butyl 3-methoxypropionate, diglyme, Dimethyl propanamide, 3-butoxy-N, N-dimethylpropanamide, and the like. These may be used alone or in combination. In addition, a solvent that does not dissolve the polyamic acid may be mixed with the solvent in the range where the produced polyamic acid is not precipitated.

In addition, the water content in the organic solvent inhibits the polymerization reaction and, furthermore, causes hydrolysis of the produced polyamic acid. Therefore, it is preferable that the organic solvent is dehydrated and dried as much as possible.

When the tetracarboxylic acid dianhydride component and the diamine component are reacted in an organic solvent, the solution in which the diamine component is dispersed or dissolved in an organic solvent is stirred to disperse or dissolve the tetracarboxylic acid dianhydride component intact or in an organic solvent A method of adding a diamine component to a solution in which a tetracarboxylic acid dianhydride component is dispersed or dissolved in an organic solvent, a method of alternately adding a tetracarboxylic acid dianhydride component and a diamine component, and the like And any of these methods may be used. When the tetracarboxylic acid dianhydride component or the diamine component is composed of a plurality of compounds, they may be reacted in a preliminarily mixed state, or they may be sequentially reacted individually. Further, the separately reacted low molecular weight compounds are mixed and reacted Or may be a high molecular weight material.

The temperature at which the tetracarboxylic acid dianhydride component is reacted with the diamine component can be selected from any of -20 to 150 ° C, preferably -5 to 100 ° C. If the concentration is excessively low, it becomes difficult to obtain a polymer having a high molecular weight. If the concentration is too high, the viscosity of the reaction liquid becomes excessively high and it becomes difficult to carry out uniform stirring. Therefore, The total concentration of the acid anhydride component and the diamine component in the reaction solution is preferably 1 to 50 mass%, more preferably 5 to 30 mass%. The reaction is carried out at a high concentration in the initial stage, and then an organic solvent can be added.

In the polymerization reaction of the polyamic acid, the ratio of the total number of moles of the tetracarboxylic acid dianhydride component to the total number of moles of the diamine component is preferably 0.8 to 1.2, more preferably 0.9 to 1.1. As in the case of the usual polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the produced polyamic acid.

&Lt; Preparation of polyimide &

The polyimide of the present invention is a polyimide obtained by dehydrocondylating the above polyamic acid and is useful as a polymer for obtaining a liquid crystal alignment film.

In the polyimide of the present invention, the dehydration / removal rate (imidization rate) of the amide acid group is not necessarily 100%, and can be arbitrarily adjusted depending on the purpose and purpose.

Examples of the method for imidizing polyamic acid include a heat imidation method in which a solution of polyamic acid is heated as it is, and a catalyst imidation method in which a catalyst is added to a solution of polyamic acid.

The temperature at which the polyamic acid is thermally imidized in the solution is 100 to 400 ° C, preferably 120 to 250 ° C, and it is preferable to carry out the removal while removing the water generated by the imidization reaction out of the system.

The catalyst imidation of polyamic acid can be carried out by adding a basic catalyst and acid anhydride to a solution of polyamic acid and stirring at -20 to 250 캜, preferably 0 to 180 캜. The amount of the basic catalyst is 0.5 to 30 moles, preferably 2 to 20 moles, of the amide acid group, and the amount of the acid anhydride is 1 to 50 moles, preferably 3 to 30 moles, of the amide acid group. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, pyridine is preferable because it has a basicity suitable for promoting the reaction. As the acid anhydride, acetic anhydride, trimellitic anhydride, pyromellitic anhydride and the like can be given. Of these, use of acetic anhydride is preferable since the purification after completion of the reaction becomes easy. The imidization rate by the catalyst imidization can be controlled by adjusting the catalyst amount, the reaction temperature, the reaction time, and the like.

The molecular weight of the polymer contained in the liquid crystal aligning agent of the present invention is preferably 5,000 or more in terms of the weight average molecular weight measured by GPC (Gel Permeation Chromatography), considering the strength of the obtained coating film, the workability at the time of forming the coating film, To 1,000,000, and more preferably from 10,000 to 150,000.

<Liquid Crystal Aligner>

The liquid crystal aligning agent of the present invention is a coating liquid for forming a liquid crystal alignment film and is a solution in which a resin component for forming a resin film is dissolved in an organic solvent. Here, the resin component contains at least one kind of polymer selected from the above-mentioned polymers of the present invention. The content of the resin component in the liquid crystal aligning agent is preferably from 1 to 20% by mass, more preferably from 3 to 15% by mass, and particularly preferably from 3 to 10% by mass.

The resin component may be all the polymer of the present invention, or may be mixed with other polymer. At that time, the content of the other polymer in the resin component is 0.5 to 15 mass%, preferably 1 to 10 mass%.

Such another polymer may be, for example, a polyamic acid or polyimide obtained by using a diamine compound other than a specific diamine compound as a diamine component to be reacted with a tetracarboxylic acid dianhydride component.

The organic solvent used in the liquid crystal aligning agent of the present invention is not particularly limited as long as it is an organic solvent capable of dissolving the resin component. Specific examples thereof are given below.

N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N- Dimethyl sulfoxide, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide,? -Butyrolactone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy- Amide, 3-butoxy-N, N-dimethylpropanamide, 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone, Hexanone, ethylene carbonate, propylene carbonate, diglyme, 4-hydroxy-4-methyl-2-pentanone and the like. These may be used alone or in combination.

The liquid crystal aligning agent of the present invention may contain components other than those described above. Examples thereof include compounds that improve the adhesion between the liquid crystal alignment film and the substrate, such as a solvent multi-substance that improves film thickness uniformity and surface smoothness when the liquid crystal aligning agent is applied.

Specific examples of the solvent (poor solvent) for improving the uniformity of the film thickness and the surface smoothness include the following.

Examples of the solvent include isopropyl alcohol, methoxymethyl pentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl But are not limited to, carbitol acetate, carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, Monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl Ether, dipropylene glycol monopro Dipropylene glycol dimethyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoacetate monopropyl ether, dipropylene glycol dimethyl ether, Hexane, n-hexane, n-pentane, n-pentane, n-butane, n-butane, Propyleneglycol monoethyl ether, methyl pyruvate, methyl pyruvate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, methyl 3-ethoxypropionate, Methoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1- Butoxy-2-propanol, 2-butoxy-1-propanol, 2,6-dimethyl-4-heptanol, Acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, lactic acid methyl ester, propyleneglycol-1-monomethylether- And a solvent having a low surface tension such as lactic acid ethyl ester, n-propyl lactate, n-butyl lactate, and lactic acid diisobutyl ester.

These poor solvents may be used alone or in combination. When the solvent is used, it is preferably 5 to 80 mass%, more preferably 20 to 60 mass%, of the total solvent contained in the liquid crystal aligning agent.

Examples of the compound that improves film thickness uniformity and surface smoothness include a fluorine-based surfactant, a silicon-based surfactant, and a nonionic surface-active agent.

More specifically, it is possible to use, for example, EF Top EF301, EF303, and EF352 (manufactured by TOKEM PRODUCTS CO., LTD.), Mega Park F171, F173 and R-30 (manufactured by Dainippon Ink and Chemicals Inc.), FLORAD FC430 and FC431 (manufactured by Sumitomo 3M ), Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.). The proportion of these surfactants to be used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass based on 100 parts by mass of the resin component contained in the liquid crystal aligning agent.

Specific examples of the compound improving the adhesion between the liquid crystal alignment film and the substrate include the following functional silane-containing compounds and epoxy group-containing compounds.

For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3 3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxy (2-aminoethyl) Aminopropyltriethoxysilane, N-trimethoxysilylpropyltriethoxysilane, N-trimethoxysilylpropyltriethoxysilane, N-trimethoxysilylpropyltriethoxysilane, N-trimethoxysilylpropyltriethoxysilane, Amine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl Acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N- Bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N- Aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neo Pentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6 Tetraglycidyl-2,4-hexanediol, N, N, N ', N', -tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglycidylamino Methyl) cyclohexane, N, N, N ', N', -tetraglycidyl-4,4'-diaminodiphenylmethane and the like.

In addition to the improvement of the adhesion between the substrate and the film, it is preferable to add the following phenoplast-type additive for the purpose of preventing deterioration of electric characteristics due to the backlight. Specific phenoplast-based additives are shown below.

[Chemical Formula 19]

When a compound improving the adhesion with a substrate is used, the amount thereof is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the resin component. If the amount is less than 0.1 part by mass, the effect of improving the adhesion can not be expected. If the amount is more than 30 parts by mass, the alignment property of the liquid crystal may be deteriorated.

The liquid crystal aligning agent of the present invention may be a dielectric substance, a conductive substance, and a liquid crystal alignment film for the purpose of changing electric characteristics such as dielectric constant and conductivity of the liquid crystal alignment film as long as the effects of the present invention are not impaired A crosslinkable compound for the purpose of increasing the hardness and density of the film at the time of the coating.

<Liquid Crystal Alignment Film and Liquid Crystal Display Device>

The liquid crystal aligning agent of the present invention can be used as a liquid crystal alignment film without being subjected to an alignment treatment in an application process such as rubbing treatment, light irradiation, or vertical orientation. At this time, the substrate to be used is not particularly limited as long as it is a substrate having high transparency, and a plastic substrate such as a glass substrate, an acrylic substrate, or a polycarbonate substrate can be used. In addition, it is preferable to use a substrate on which an ITO electrode or the like for liquid crystal driving is formed from the viewpoint of simplifying the process. In a reflection type liquid crystal display element, an opaque material such as a silicon wafer can be used only for a substrate on one side, and a material for reflecting light such as aluminum can be used for the electrode in this case.

The application method of the liquid crystal aligning agent is not particularly limited, but it is generally carried out industrially by a method such as screen printing, offset printing, flexographic printing, inkjet or the like. Other coating methods include dip, roll coater, slit coater, spinner and the like, and these may be used depending on the purpose.

The baking after the liquid crystal aligning agent is applied on the substrate can be carried out by heating means such as a hot plate at 50 to 300 캜, preferably 80 to 250 캜, and the solvent can be evaporated to form a coat. When the thickness of the coating film formed after firing is too large, the power consumption of the liquid crystal display element is disadvantageously deteriorated. When the thickness is too thin, the reliability of the liquid crystal display element may be deteriorated. Therefore, the thickness is preferably 5 to 300 nm, 10 to 100 nm. When the liquid crystal is horizontally oriented or tilted, the coated film after firing is subjected to rubbing, polarized ultraviolet irradiation, or the like.

In the liquid crystal display element of the present invention, a substrate on which a liquid crystal alignment film is formed from the liquid crystal aligning agent of the present invention is obtained by the above-mentioned technique, and then a liquid crystal cell is produced by a known method to form a liquid crystal display element.

For example, a pair of substrates on which a liquid crystal alignment film is formed is prepared, spacers are dispersed on the liquid crystal alignment film of the substrate of the single chamber, and the substrates of the other single chamber are bonded to each other ), A method of sealing the liquid crystal by injecting it under reduced pressure, or a method in which liquid crystal is dropped on the surface of the liquid crystal alignment film on which the spacer is dispersed, and the substrate is then sealed by bonding. The thickness of the spacer is preferably 1 to 30 占 퐉, more preferably 2 to 10 占 퐉.

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the interpretation of the present invention is not limited to these examples. The abbreviations used in Examples and the like, and the methods for characterization are as follows.

[Chemical Formula 20]

<Organic solvent>

NMP: N-methyl-2-pyrrolidone  BCS: butyl cellosolve

<Additives>

LS-4668: 3-glycidoxypropyltriethoxysilane

<Viscosity Measurement>

The viscosity of the solution was measured at a temperature of 25 占 폚 with a sample amount of 1.1 ml and a cone TE-1 (1 占 34 ', R24) using an E-type viscometer TVE-22H (Toki Industries Co., Ltd.).

&Lt; Production of liquid crystal display element &

First, a substrate with electrodes was prepared. The substrate is a glass substrate having a rectangular shape of 30 mm in length x 35 mm in width and 0.7 mm in thickness. On the substrate, an IZO electrode having a beta-pattern constituting the counter electrode as the first layer is formed. On the first-layer counter electrode, a SiN (silicon nitride) film formed by the CVD method is formed as the second layer. The thickness of the second-layer SiN film is 500 nm and functions as an interlayer insulating film. On the second-layer SiN film, pixel electrodes on the combs formed by patterning the IZO film as the third layer are disposed to form two pixels, i.e., the first pixel and the second pixel. The size of each pixel is 10 mm in length and 5 mm in width. At this time, the first layer counter electrode and the third layer pixel electrode are electrically insulated by the action of the second layer SiN film.

The third-layer pixel electrode has a comb-like shape formed by arranging a plurality of &quot; square &quot; -shaped electrode elements whose central portions are curved. The width of each electrode element in the width direction is 3 占 퐉, and the interval between the electrode elements is 6 占 퐉. Since the pixel electrode forming each pixel is constituted by arranging a plurality of bent electrode elements in the central portion, the shape of each pixel is not rectangular, , And has a shape similar to "bold" in bold letters. Each pixel has a first region on the upper side of the bent portion and a second region on the lower side, which are vertically divided with the bent portion at the center as a boundary.

When the first region and the second region of each pixel are compared with each other, the electrode elements of the pixel electrodes constituting the first region and the second region are different from each other. In other words, when the rubbing direction of a liquid crystal alignment film to be described later is taken as a reference, the electrode elements of the pixel electrodes are formed so as to form an angle of +10 degrees (clockwise) in the first region of the pixel, The element is formed so as to form an angle (clockwise direction) of -10 degrees. Thus, the first region and the second region of each pixel are arranged such that the directions of rotation (inflation / switching) of the liquid crystal caused by application of a voltage between the pixel electrode and the counter electrode are opposite to each other Consists of.

Next, after the liquid crystal aligning agent was filtered with a filter having a pore diameter of 1.0 탆, the prepared substrate on which the above-described electrode was adhered and the opposed substrate were coated with an ITO film on the back surface and a columnar spacer having a height of 4 탆 Respectively. Then, the substrate was dried on a hot plate at 80 DEG C for 2 minutes, and then fired at 230 DEG C for 20 minutes to obtain a polyimide film having a film thickness of 60 nm on each substrate. This polyimide film was subjected to rubbing (roll diameter: 120 mm, rotation speed: 500 rpm, moving speed: 30 mm / sec, indentation amount: 0.3 mm) in a predetermined rubbing direction with a rayon cloth, And dried at 80 DEG C for 10 minutes to obtain a liquid crystal alignment film.

Using the two types of substrates on which the obtained liquid crystal alignment films were formed, the rubbing directions were combined so as to be anti-parallel, leaving the liquid crystal injection ports and sealing the periphery, thereby producing empty cells having a cell gap of 3.5 mu m. A liquid crystal (MLC-3019, manufactured by Merck Co.) was vacuum-injected into the empty cell at room temperature, and then the injection port was sealed to obtain an anti-parallel alignment liquid crystal cell. The resulting liquid crystal cell constitutes an FFS mode liquid crystal display element. Thereafter, the resulting liquid crystal cell was heated at 120 DEG C for 1 hour, left standing overnight, and used for evaluation.

<Evaluation of Liquid Crystal Alignment Property>

Using the liquid crystal cell obtained above, an AC voltage of 10 VPP was applied for 168 hours at a frequency of 30 Hz under a constant temperature environment of 60 占 폚. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited, and left at room temperature for one day. After leaving the liquid crystal cell, the liquid crystal cell was placed between two polarizers arranged so that the polarization axis thereof was orthogonal to each other, and the backlight was turned on in the voltage unapplied state, and the arrangement angle of the liquid crystal cell was adjusted so that the luminance of the transmitted light was minimized. The rotation angle at which the liquid crystal cell was rotated from the angle at which the second area of the first pixel was darkest to the angle at which the first area became darkest was calculated as the angle?. Similarly, in the second pixel, the second region is compared with the first region, and the same angle? Is calculated. The average value of the angle DELTA values of the first pixel and the second pixel was calculated as the angle DELTA of the liquid crystal cell.

The smaller the angle? Of the liquid crystal cell, the higher the liquid crystal alignment property of the liquid crystal alignment film.

<Gardner color number>

The obtained liquid crystal aligning agent was allowed to stand at room temperature for 24 hours, and then the number of colors of Gardner was measured. The Gardner color number representing the color tone was measured based on Japanese Industrial Standard JIS K 0071-2. The smaller the number of Gardner colors, the lighter the color of the obtained liquid crystal aligning agent.

(Synthesis Example 1)

0.473 g (2.58 mmol) of DA-1 and 2.54 g (10.4 mmol) of DA-4 were weighed in a 50 ml four-necked flask equipped with a stirrer and 46.5 g of NMP And dissolved by stirring while nitrogen was being supplied. While stirring the diamine solution, 2.71 g (12.4 mmol) of CA-2 was added and stirred at room temperature for 2 hours and then stirred at 50 캜 for 24 hours to obtain a polyamic acid solution (PAA-1, viscosity: 510.7 mPa · s).

(Synthesis Example 2)

1.55 g (5.18 mmol) of DA-1 and 1.90 g (7.78 mmol) of DA-4 were weighed in a 50 ml four-necked flask equipped with a stirrer and 54.6 g of NMP was added , And dissolved with stirring while nitrogen was being supplied. 2.71 g (12.4 mmol) of CA-2 was added while stirring the diamine solution, stirred at room temperature for 2 hours and then stirred at 50 占 폚 for 24 hours to obtain a polyamic acid solution (PAA-2, viscosity: 505.4 mPa · s).

(Synthesis Example 3)

A 50 ml four-necked flask equipped with a stirrer was charged with 0.773 g (2.58 mmol) of DA-1, 2.22 g (9.09 mmol) of DA-4 and 0.724 g mmol), 46.5 g of NMP was added, and the mixture was stirred to dissolve while nitrogen was being fed. 2.71 g (12.4 mmol) of CA-2 was added while stirring the diamine solution, stirred at room temperature for 2 hours and then stirred at 50 占 폚 for 24 hours to obtain a polyamic acid solution (PAA-3, viscosity: 505.4 mPa · s).

(Synthesis Example 4)

0.473 g (2.58 mmol) of DA-1 and 2.98 g (10.4 mmol) of DA-5 were weighed in a 50 ml four-necked flask equipped with a stirrer and 47.4 g of NMP And dissolved by stirring while nitrogen was being supplied. 2.71 g (12.4 mmol) of CA-2 was added while stirring the diamine solution, stirred at room temperature for 2 hours and then stirred at 50 캜 for 24 hours to obtain a polyamic acid solution (PAA-4, viscosity: 525.3 mPa · s).

(Synthesis Example 5)

1.56 g (5.21 mmol) of DA-1 and 2.23 g (7.79 mmol) of DA-5 were weighed in a 50 ml four-necked flask equipped with a stirrer and 47.7 g of NMP And dissolved by stirring while nitrogen was being supplied. The diamine solution was added with 2.71 g (12.4 mmol) of CA-2 and stirred at room temperature for 2 hours and then stirred at 50 캜 for 24 hours to obtain a polyamic acid solution (PAA-5, viscosity: 510.4 mPa 揃 s ).

(Synthesis Example 6)

A 50 ml four-necked flask equipped with a stirrer was charged with 0.778 g (2.60 mmol) of DA-1, 2.60 g (9.08 mmol) of DA-5 and 0.724 g mmol), 50.0 g of NMP was added, and the mixture was stirred to dissolve while nitrogen was being fed. While stirring the diamine solution, 2.71 g (12.4 mmol) of CA-2 was added and stirred at room temperature for 2 hours and then stirred at 50 ° C for 24 hours to obtain a polyamic acid solution (PAA-6, viscosity: 498.1 mPa · s).

(Comparative Synthesis Example 1)

A 50 ml four-necked flask equipped with a stirrer was charged with 2.79 g (14.0 mmol) of DA-3, and 47.1 g of NMP was added thereto. The mixture was stirred to dissolve while nitrogen was being supplied. While stirring the diamine solution, 2.44 g (12.4 mmol) of CA-1 was added and stirred at 15 캜 for 2 hours to obtain a polyamic acid solution (PAA-7, viscosity: 121.1 mPa s).

(Comparative Synthesis Example 2)

0.518 g (2.60 mmol) of DA-3 and 2.51 g (10.3 mmol) of DA-4 were weighed in a 50 ml four-necked flask equipped with a stirrer and 42.3 g of NMP was added , And dissolved with stirring while nitrogen was being supplied. 2.71 g (12.4 mmol) of CA-2 was added while stirring the diamine solution, stirred at room temperature for 2 hours and then stirred at 50 占 폚 for 24 hours to obtain a polyamic acid solution (PAA-8, viscosity: 531.5 mPa · s).

(Comparative Synthesis Example 3)

1.04 g (5.21 mmol) of DA-3 and 1.91 g (7.82 mmol) of DA-4 were weighed in a 50 ml four-necked flask equipped with a stirrer and 41.4 g of NMP was added , And dissolved with stirring while nitrogen was being supplied. 2.71 g (12.4 mmol) of CA-2 was added while stirring the diamine solution, stirred at room temperature for 2 hours and then stirred at 50 占 폚 for 24 hours to obtain a polyamic acid solution (PAA-9, viscosity: 542.2 mPa · s).

(Comparative Synthesis Example 4)

0.51 g (2.56 mmol) of DA-3 and 2.97 g (10.4 mmol) of DA-5 were weighed in a 50 ml four-necked flask equipped with a stirrer and 47.2 g of NMP was added , And dissolved with stirring while nitrogen was being supplied. 2.71 g (12.4 mmol) of CA-2 was added while stirring the diamine solution, stirred at room temperature for 2 hours and then stirred at 50 캜 for 24 hours to obtain a polyamic acid solution (PAA-10, viscosity: 547.1 mPa · s).

(Comparative Synthesis Example 5)

0.51 g (2.56 mmol) of DA-3 and 2.97 g (10.4 mmol) of DA-5 were weighed in a 50 ml four-necked flask equipped with a stirrer and 47.2 g of NMP was added , And dissolved with stirring while nitrogen was being supplied. While stirring the diamine solution, 2.71 g (12.4 mmol) of CA-2 was added and stirred at room temperature for 2 hours and then stirred at 50 캜 for 24 hours to obtain a polyamic acid solution (PAA-11, viscosity: 547.1 mPa · s).

(Comparative Synthesis Example 6)

In a 50 ml four-necked flask equipped with a stirrer, 3.29 g (11.0 mmol) of DA-1 was weighed, and 46.1 g of NMP was added. While nitrogen was being supplied, the mixture was stirred and dissolved . 1.91 g (9.7 mmol) of CA-1 was added while stirring the diamine solution, and the mixture was stirred at 15 캜 for 2 hours to obtain a polyamic acid solution (PAA-12, viscosity: 121.1 mPa s).

(Comparative Synthesis Example 7)

A 50-ml four-necked flask equipped with a stirrer was charged with 2.77 g (13.0 mmol) of DA-2, and 46.1 g of NMP was added. The mixture was stirred to dissolve while nitrogen was being supplied. 2.34 g (11.9 mmol) of the acid dianhydride (CA-1) was added while stirring the diamine solution, and the mixture was stirred at 15 캜 for 2 hours. Thereafter, a polyamic acid solution (PAA-13 viscosity: 110.4 mPa 揃 s) .

&Lt; Examples 1 to 6 and Comparative Examples 1 to 7 &gt;

24.0 g of each of 10 to 12% of the polyamic acid solutions PAA-1 to PAA13 obtained in the above-mentioned Synthesis Examples 1 to 6 and Comparative Synthesis Examples 1 to 7 was collected, and 5.6 g of NMP and 8.00 g of BCS (AL-1) to (AL-13) were obtained by adding 2.4 g of a mixed solution containing 1% by weight of bisphenol A and 1% by weight of LS-4668 with stirring and stirring at room temperature for 2 hours.

<Evaluation>

The liquid crystal alignability and the Gardner color number described above were evaluated for each of the liquid crystal aligning agents (AL-1) to (AL-13) of Examples 1 to 6 and Comparative Examples 1 to 7 obtained above. The results are shown in Table 1. In Table 1, the Gardner color number &quot; - &quot; means unmeasured.

Industrial availability

The liquid crystal aligning agent of the present invention is used in a wide range of fields such as a large liquid crystal display device requiring a high definition and a low cost and a mobile liquid crystal display device such as a smart phone and a mobile phone.

The entire contents of the specification, claims, drawings and summary of Japanese Patent Application No. 2016-168461 filed on August 30, 2016 are hereby incorporated herein by reference as the disclosure of the specification of the present invention.

Claims (8)

At least one member selected from the group consisting of a polyamic acid obtained by reacting a diamine component containing a diamine having a structure represented by the following formula [1] with a tetracarboxylic acid dianhydride component, and a polyimide obtained by imidizing the polyamic acid &Lt; / RTI &gt; of a liquid crystal aligning agent.

(Wherein A represents a thermally-cleavable group which is substituted with a hydrogen atom by heating at a temperature of 150 to 300 DEG C. The hydrogen atom of the benzene ring is substituted with an alkyl group or alkoxy group having 1 to 5 carbon atoms or a halogen group * Indicates a combined hand.) The method according to claim 1,
And the thermally-cleavable group is a tert-butoxycarbonyl group or a 9-fluorenylmethoxycarbonyl group. 3. The method according to claim 1 or 2,
A liquid crystal aligning agent wherein the diamine having the structure represented by the formula [1] is a diamine represented by any one of the following formulas. Boc in the formula represents a tert-butoxycarbonyl group.

4. The method according to any one of claims 1 to 3,
The content of the diamine having the structure represented by the formula [1] in the diamine component is 5 to 95 mol%. 5. The method according to any one of claims 1 to 4,
Wherein the tetracarboxylic acid dianhydride component is a compound represented by the following formula [7].

(Wherein Z ₁ is a tetravalent organic group having 4 to 13 carbon atoms and further has an aromatic cyclic hydrocarbon group) 6. The method of claim 5,
And Z &lt; ₁ &gt; is a structure represented by any one of the following formulas [7a] to [7k].

A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 6. A liquid crystal display element comprising the liquid crystal alignment film according to claim 7.