KR101756244B1 - Liquid crystal aligning agent, liquid crystal alignment layer and liquid crystal display - Google Patents

Abstract

식(1)에 있어서, R¹은 수소, -OH, -NH-C₄H₉, -N(CH₃)₂, -N(C₂H₅)₂, -N(CH₂CH=CH₂)₂, -NH-CH₂CH=CH₂, 할로겐, 탄소수 1∼20의 알킬, 탄소수 1∼20의 알콕시, 탄소수 2∼20의 알케닐, 탄소수 6∼20의 아릴, 탄소수 7∼20의 아릴알킬, 또는 하기의 구조임:

The present invention relates to a liquid crystal alignment composition comprising a polymer component A, which is a polyamic acid obtained by reacting a diamine mixture comprising at least one of the diamines represented by formula (1) and at least one of other diamines with a tetracarboxylic dianhydride, Jay. By using the liquid crystal alignment film formed using the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal display device having a high voltage retention ratio and good thermal reliability and light resistance.

In formula (1), R ¹ is hydrogen, -OH, -NH-C ₄ H ₉ , -N (CH ₃ ) ₂ , -N (C ₂ H ₅ ) ₂ , -N (CH ₂ CH═CH ₂ ) ₂ , -NH-CH ₂ CH = CH ₂ , halogen, alkyl of 1 to 20 carbon atoms, alkoxy of 1 to 20 carbon atoms, alkenyl of 2 to 20 carbon atoms, aryl of 6 to 20 carbon atoms, aryl of 7 to 20 carbon atoms Alkyl, or the following structure:

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal alignment material, a liquid crystal alignment film, and a liquid crystal display device,

The present invention relates to a liquid crystal aligning agent containing a polyamic acid obtained by reacting a diamine having a triazine structure with a tetracarboxylic dianhydride, and a use thereof.

The driving method of the liquid crystal display device is a twisted nematic (TN) mode, a super twisted nematic (STN) mode, an in plane switching (IPS) mode, and a vertical alignment : VA) mode.

Although these liquid crystal display devices require an external light source for their operation, they are classified into two types, namely, a transmissive type and a reflective type, depending on the type of the external light source. The transmissive type is a type of liquid crystal in which display is performed using a backlight of the screen as a light source. In contrast, the reflection type is a type in which display is performed by reflection of external light. Particularly, in the transmissive liquid crystal display device, the liquid crystal alignment film is always exposed to the backlight during operation, and the temperature rise of the liquid crystal display device itself due to the backlight irradiation is considered. On the other hand, in a reflection type liquid crystal, sunlight can be assumed as a light source when it is used outdoors. Since sunlight contains ultraviolet light, it causes deterioration of the liquid crystal alignment film (see, for example, Patent Documents 1 to 3).

In addition, liquid crystal dropping process (ODF process: One Drop Fill process) may be used in the liquid crystal injection process in order to improve the yield, especially in the process of manufacturing a large liquid crystal display device. In the liquid crystal dropping method, usually, an ultraviolet curing type sealant is used. That is, in the liquid crystal dropping method, since the liquid crystal alignment film is exposed to ultraviolet light, development of a liquid crystal alignment film with good UV resistance is required (see, for example, Patent Document 4).

As described above, in recent years, liquid crystal display devices have been processed under severe conditions or used in harsh environments. Therefore, as one of the characteristics required for a liquid crystal aligning agent, electrical characteristics such as voltage retention rate after exposure to light or heat or after being driven for a long time in such an environment have become important.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2008-70463 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-292940 [Patent Document 3] Japanese Patent Application Publication No. 2002-333624 [Patent Document 4] Japanese Patent Application Laid-Open No. 2001-174829

An object of the present invention is to provide, for example, a liquid crystal aligning agent for a liquid crystal display element which solves the above problems and is excellent in reliability. A further object of the present invention is to provide a liquid crystal display element provided with a liquid crystal alignment film formed using the liquid crystal aligning agent.

DISCLOSURE OF THE INVENTION When a polyamic acid obtained by reacting a 2,4-diamino-1,3,5-triazine derivative with a tetracarboxylic dianhydride is used for a liquid crystal alignment film, A liquid crystal display element having a liquid crystal alignment layer has a high voltage retention ratio and an excellent effect of improving thermal reliability and light resistance.

The liquid crystal aligning agent of the present invention can be represented by the following [1].

[1] A polyamic acid or a derivative thereof obtained by reacting a diamine mixture composed of at least one of diamines represented by formula (1) and at least one other diamine with a tetracarboxylic dianhydride is referred to as a polymer component A;

A polyamic acid or a derivative thereof obtained by reacting at least one of the other diamines with a tetracarboxylic dianhydride is referred to as a polymer component B;

A liquid crystal aligning agent comprising a polymer component A as an essential component and a polymer component B as an optional component.

In formula (1), R ¹ is hydrogen, -OH, -NH-C ₄ H ₉ , -N (CH ₃ ) ₂ , -N (C ₂ H ₅ ) ₂ , -N (CH ₂ CH═CH ₂ ) ₂ , -NH-CH ₂ CH = CH ₂ , halogen, alkyl of 1 to 20 carbon atoms, alkoxy of 1 to 20 carbon atoms, alkenyl of 2 to 20 carbon atoms, aryl of 6 to 20 carbon atoms, aryl of 7 to 20 carbon atoms Alkyl, or the following structure.

According to the present invention, it is possible to provide a liquid crystal display element having a high voltage holding ratio, heat reliability, and light resistance, a liquid crystal alignment film therefor, a polymer capable of forming the liquid crystal alignment film, and a liquid crystal aligning agent.

The usage of the terms in this specification is as follows.

The term "liquid crystalline compound" is a generic term for a compound having a liquid crystal phase and a compound which does not have a liquid crystal phase but is useful as a component of a liquid crystal composition. A liquid crystal compound, a liquid crystal composition, and a liquid crystal display element may be referred to as a compound, a composition, or an element, respectively.

The diamine represented by the formula (1) may be represented by the diamine (1). The diamines represented by other formulas may also be abbreviated (abbreviated) in some cases.

The tetracarboxylic dianhydride may be abbreviated as an acid anhydride. The tetracarboxylic dianhydride represented by the formula (T1) may be represented by an acid anhydride (T1). The same applies to tetracarboxylic dianhydrides represented by other formulas.

In the chemical structural formula, a symbol enclosed by a letter (for example, A) in a hexagon indicates that it is ring (ring A).

A substituent whose bonding position with carbon constituting the ring is not clear means that the bonding position is free within a range in which there is no chemical problem.

The term "arbitrary" used in the definition of the formula means "to be freely selectable not only in position but also in number ". For example, the expression "arbitrary A may be substituted with B, C, D or E" means that one A may be substituted with B, C, D, or E, Or A may be substituted with B, C, D, or E, and at least two of A substituted with B, A substituted with A, D substituted with D, and A substituted with E may be mixed . When arbitrary -CH ₂ - may be substituted with -O-, substitution such as formation of the linking group -OO- is not included as a result.

When the same symbol is used in a plurality of expressions, it means that the same group has the same definition range, but it does not mean that all the expressions must be the same group at the same time. In such a case, the same group may be selected in a plurality of expressions, and different groups may be selected for each expression.

The present invention consists of the above-mentioned [1] and the following [2] - [9].

[2] The liquid crystal aligning agent according to [1], wherein R ¹ is vinyl or phenyl.

[3] The liquid crystal aligning agent according to [1] or [2], wherein the tetracarboxylic dianhydride is at least one compound represented by formula (T1) to formula (T8).

[4] The liquid crystal aligning agent according to [3], wherein the tetracarboxylic dianhydride is at least one compound represented by formula (T1), formula (T6) and formula (T7).

[5] The liquid crystal aligning agent according to any one of [1] to [4], wherein the other diamine is a diamine selected from the group of compounds represented by the formulas (3) to (6)

In formula (3), Y is alkylene having 1 to 7 carbon atoms, and arbitrary -CH ₂ - of the alkylene may be substituted with -O- or -S-; R ² is independently alkyl of 1 to 3 carbon atoms; k is independently 0 or 1;

In formula (4), X ¹ is independently -CH ₂ - or -O-; X ² is alkylene having 1 to 8 carbon atoms, and any hydrogen of the alkylene may be substituted with methyl or -CF ₃ ;

In formula (5), X ¹ is independently alkylene having 1 to 6 carbon atoms or -O-; X ³ is a single bond or alkylene having 1 to 3 carbon atoms, and the ring T is 1,4-phenylene or 1,4-cyclohexylene, h is 0 or 1; R ³ is hydrogen or alkyl having 1 to 30 carbon atoms, and any -CH ₂ - of the alkyl may be substituted with -O-, -CH = CH- or -C≡C- when the number of carbon atoms is 2 to 30 ;

In formula (6), A ¹ represents a single bond, -O-, -COO-, -OCO-, -CO-, -CONH-, -NHCO-, alkylene of 1 to 4 carbon atoms or 1,4- Hexylene; R ⁴ is a group having a steroid skeleton, or a group represented by the formula (A);

In formula (A), A ² and A ³ are independently a single bond, -O-, -COO-, -OCO-, -CONH-, -NHCO-, -CH = CH- or alkyl of 1 to 12 carbon atoms It is wen;

R ⁵ and R ⁶ are independently fluorine or methyl, f and g are independently integers of from 0 to 2;

The ring S can be selected from the group consisting of 1,4-phenylene, 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, pyrimidine- 1,4-diyl, naphthalene-1,5-diyl, naphthalene-2,6-diyl, naphthalene-2,7-diyl, or anthracene-9,10-diyl;

R ⁷ is H, F, -OH, fluorinated alkyl, alkyl of 1 to 30 carbon atoms, 1 to 30 carbon atoms alkoxy of 1 to 30 carbon _{atoms, -CN, -OCH 2 F, -OCHF} 2 or -OCF _3, and;

c, d and e are independently integers of from 0 to 3, with c + d + e? 1; When e is 2 or 3, the plurality of rings S may all be the same ring or may be composed of at least two different rings.

[6] A diamine mixture comprising at least one of the diamines represented by the formula (1) and at least one other diamine, wherein the content of the diamine represented by the formula (1) is in the range of 5 to 30 mol %. The liquid crystal aligning agent according to any one of [1] to [5].

[7] A process for producing a polyamic acid according to [1], which comprises only a polymer component A which is a polyamic acid obtained by reacting a diamine mixture comprising at least one of diamines represented by the formula (1) and at least one of other diamines with a tetracarboxylic dianhydride, To (6) above.

[8] A liquid crystal alignment film obtained from the liquid crystal aligning agent described in any one of [1] to [7].

[9] A liquid crystal display element comprising the liquid crystal alignment film according to [8].

The polymer component A which is an essential component of the liquid crystal aligning agent of the present invention is a polyamic acid or a derivative thereof obtained by reacting a diamine mixture comprising at least one of diamines (1) and at least one other diamine with an acid anhydride.

In formula (1), R ¹ is hydrogen, -OH, -NH-C ₄ H ₉ , -N (CH ₃ ) ₂ , -N (C ₂ H ₅ ) ₂ , -N (CH ₂ CH═CH ₂ ) ₂ , -NH-CH ₂ CH = CH ₂ , halogen, alkyl of 1 to 20 carbon atoms, alkoxy of 1 to 20 carbon atoms, alkenyl of 2 to 20 carbon atoms, aryl of 6 to 20 carbon atoms, aryl of 7 to 20 carbon atoms Alkyl, or the following structure.

On the other hand, examples of derivatives of the polyamic acid are soluble polyimide, polyamic acid ester and polyamic acid amide. More specifically, a polyamic acid-polyamide copolymer obtained by the reaction of 1) polyimide, 2) partially imidized polyamic acid, 3) polyamic acid ester, and 4) a part of tetracarboxylic acid dianhydride with dicarboxylic acid (derivative) And 5) a polyamideimide obtained by subjecting the polyamic acid-polyamide copolymer to dehydration ring-closure reaction. Except for the examples, in the following description, "polyamic acid" is used as a generic term of polyamic acid and derivatives thereof unless otherwise specified.

Examples of the diamine (1) are shown below.

Of these, diamines (1-1) to diamines (1-3), diamines (1-7), diamines (1-9), diamines (1-13), diamines (1-20) ), And diamine (1-7), diamine (1-9), diamine (1-13) and diamine (1-20) are more preferable. The diamine (1) may be used alone, or two or more thereof may be used in combination. One or more of diamines (1) and diamines other than diamines (1) may be used in combination.

The other diamine is preferably a diamine selected from the group of diamines represented by the formulas (3) to (6).

In the formula (3), Y is alkylene having 1 to 7 carbon atoms, and any -CH ₂ - of the alkylene may be substituted with -O- or -S-. R ² is independently alkyl having 1 to 3 carbon atoms, and k is independently 0 or 1. The bonding position of the amino group to the benzene ring is preferably a meta position or a para position with respect to Y, and more preferably a para position.

Wherein X ¹ is independently -CH ₂ - or -O-; X ² is alkylene having 1 to 8 carbon atoms, and arbitrary hydrogen of the alkylene may be substituted with methyl or -CF ₃ . It is preferable that the two X < ^{1 >} are the same coupler. The bonding position of the amino group to the benzene ring is preferably a meta position or a para position with respect to X ¹ , and more preferably a para position.

Wherein X ¹ is independently alkylene having 1 to 6 carbon atoms or -O-; X ³ is a single bond or alkylene having 1 to 3 carbon atoms, and the ring T is 1,4-phenylene or 1,4-cyclohexylene, h is 0 or 1; R ³ is hydrogen or alkyl having 1 to 30 carbon atoms, and any -CH ₂ - of the alkyl may be substituted with -O-, -CH = CH- or -C≡C- when the number of carbon atoms is 2 to 30 . The preferred range of the number of carbon atoms is 1 to 10. The bonding position of the amino group to the benzene ring is preferably a meta position or a para position with respect to X ¹ , and more preferably a para position.

Wherein A ¹ is a single bond, -O-, -COO-, -OCO-, -CO-, -CONH-, -NHCO-, alkylene of 1 to 4 carbon atoms or 1,4-cyclohexylene; R ⁴ is a group having a steroid skeleton, or a group represented by the formula (A).

Wherein A ² and A ³ are independently a single bond, -O-, -COO-, -OCO-, -CONH-, -NHCO-, -CH = CH- or alkylene of 1 to 12 carbon atoms; R ⁵ and R ⁶ are independently fluorine or methyl, and f and g are independently an integer of 0 to 2. The ring S can be selected from the group consisting of 1,4-phenylene, 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, pyrimidine- 1,4-diyl, naphthalene-1,5-diyl, naphthalene-2,6-diyl, naphthalene-2,7-diyl, or anthracene-9,10-diyl. R ⁷ is H, F, -OH, _{alkoxy, -CN, -OCH 2 F, -OCHF} 2 or -OCF of fluorinated alkyl, of 1 to 30 carbon atoms in the alkyl, of 1 to 30 carbon atoms having a carbon number of 1 to 30 _3, and therefore The alkyl, fluorinated alkyl and alkoxy preferably have 1 to 10 carbon atoms. c, d and e are independently an integer of 0 to 3, and c + d + e? 1. When e is 2 or 3, the plurality of rings S may all be the same ring or may be composed of at least two different rings. The bonding position of two amino groups to the benzene ring is preferably in the meta position with respect to A < ^{1 &} gt ;.

Preferable specific examples of the diamine (3) are shown below.

Among these preferred examples, diamines (3-1) to diamines (3-4), diamines (3-6), diamines (3-8), diamines (3-13), diamines (3-14), diamines 3-19), diamines (3-20) and diamines (3-21) are more preferable.

Preferred specific examples of the diamine (4) are shown below.

Among these preferred examples, diamine (4-1) and diamine (4-5) to diamine (4-9) are more preferable.

Preferable specific examples of the diamine (5) are shown below.

Preferred examples of these diamines (5) include diamines (5-3) to diamines (5-8), diamines (5-15) to diamines (5-18), diamines (5-23), and diamines (5- 24) is more preferable.

Preferable examples of the diamine (6) are shown below.

In these formulas, R ⁸ is alkyl of 3 to 12 carbon atoms or alkoxy of 3 to 12 carbon atoms, preferably alkyl of 5 to 12 carbon atoms or alkoxy of 5 to 12 carbon atoms. R ⁹ is alkyl of 1 to 10 carbon atoms or alkoxy of 1 to 10 carbon atoms, preferably alkyl of 3 to 10 carbon atoms or alkoxy of 3 to 10 carbon atoms.

In these formulas, R ¹⁰ is alkyl of 4 to 16 carbon atoms, preferably alkyl of 6 to 16 carbon atoms. R ¹¹ is an alkyl having 6 to 20 carbon atoms, preferably an alkyl having 8 to 20 carbon atoms.

In formulas (6-18) to (6-38), R ¹² is alkyl of 1 to ¹² carbon atoms or alkoxy of 1 to 12 carbon atoms, preferably alkyl of 3 to 12 carbon atoms or alkoxy of 3 to 12 carbon atoms to be. R ¹³ is hydrogen, fluorine, alkyl having 1 to 12 carbon atoms, having 1 to 12 carbon atoms, cyano, and -OCH ₂ F, -OCHF ₂ or -OCF ₃ of a, preferably alkyl having a carbon number of 3 to 12 carbon atoms or a 3 Lt; / RTI > A ⁹ is alkylene having 1 to 12 carbon atoms.

Among diamines (6), preferred are diamines (6-1) to diamines (6-11), diamines (6-2), diamines (6-4), diamines (6-5) (6-6) is more preferable.

In the present invention, other diamines other than the diamines (3) to (6) may be further used. An example of such another diamine is the siloxane-based diamine represented by the formula (7).

Wherein R ²² and R ²³ independently represent alkyl having 1 to 3 carbon atoms or phenyl, R ²¹ independently represents methylene, phenylene or alkyl-substituted phenylene, x is independently an integer of 1 to 6 , and y represents an integer of 1 to 10.

Other diamines used in the present invention can be determined according to the required characteristics of the electric field system in the liquid crystal display element. In the former system represented by TN system or VA system, a relatively large pretilt angle is required, so that diamine (5) or diamine (6) is mainly used. Also, diamine (3) or diamine (4) can be used to control the pretilt angle. In the transverse electric field system, the diameters of the diamine (3) and the diamine (4) are mainly used because the pretilt angle is small and the liquid crystal orientation is required. Such a combination of diamines is preferable from the viewpoint of improving the black display characteristic of a liquid crystal display element of a transverse electric field system when no voltage is applied.

In the above-mentioned diamine mixture to be used in the present invention, the use ratio of the diamine (1) is preferably 5 to 30 mol% based on the total amount of the diamine mixture. The content of the diamine (1) is preferably not less than 5 mol% in order to obtain the above-mentioned improvement effect on the electric characteristics, that is, the heat reliability and the light resistance improving effect. In order not to hinder the synthesis of the polyamic acid, .

In the VA system, the TN system, and the OCB system, which are the conventional system, the expression of a comparatively large pretilt angle is essential. In this case, it is necessary to use at least one of diamine (5) and diamine (6), which are diamines having side chains, in combination with diamine (1). By controlling the kinds and ratios of these diamines, a predetermined pretilt angle can be expressed. When a polymer is obtained by using these diamines in combination, the liquid crystal display element to which the polymer is applied can be a liquid crystal display element of the previous system in which the voltage holding ratio is further improved.

As the acid anhydride to be reacted with the diamine, any of aromatic tetracarboxylic acid dianhydride, alicyclic tetracarboxylic acid dianhydride and aliphatic tetracarboxylic acid dianhydride may be used so long as the effect of the present invention is not impaired. One or two or more of them can be selected and used.

Examples of the acid anhydrides usable in the present invention are shown below.

Of the above examples, more preferred acid anhydrides are shown below.

Among these acid anhydrides (T1) to acid anhydrides (T8), acid anhydrides (T1), acid anhydrides (T6) and acid anhydrides (T7) are more preferable.

The molecular weight of the polyamic acid obtained by the reaction between the diamine and the acid anhydride is, for example, a weight average molecular weight (Mw) in terms of polystyrene as determined by a gel permeation chromatography (GPC) method, preferably 10,000 to 500,000 Preferably 20,000 to 200,000.

The polyamic acid can be produced in the same manner as the known polyamic acid used for forming the polyimide film, except that the diamine and the acid anhydride described above are used. For example, at least one of the diamines (1) or at least one of the diamines (1) and at least one of the diamines (3) to diamines (6) is added to a reaction vessel equipped with a feed inlet, a nitrogen inlet, a thermometer, a stirrer and a condenser. (3) to at least one other diamine other than the diamine (6), and if necessary, the amount of the monoamine, in addition to the diamine . Next, at least one of a solvent (for example, N-methyl-2-pyrrolidone or dimethylformamide which is an amide-based polar solvent) and an acid anhydride and, if necessary, a carboxylic anhydride are added and heated under stirring Respectively. At this time, the total amount of the acid anhydride is preferably approximately the same mole (molar ratio of 0.9 to 1.1) as the total molar amount of diamine.

The polyamic acid thus obtained contains the chemical structure formed by the reaction of the diamine (1) with the acid anhydride, and the chemical structure formed by the reaction of the other diamine and the acid anhydride. Examples of the chemical structure of the reaction between the diamine (1) and the acid anhydride include structural units represented by the following formulas (10) and (11). Examples of the structure of the reaction between the other diamine and the acid anhydride include structural units represented by the following formulas (12) and (13). In the formulas (10) to (13), Q ¹ is a residue of an acid anhydride, R ¹ is the same as R ¹ in formula (1), and Q ² is a residue of another diamine.

The structure of formulas 10 to 13 can be specified by IR or NMR. More specifically, the polyamic acid in the present invention can be identified by precipitating with a large amount of a poor solvent, completely separating the solid component and the solvent by filtration, and analyzing by IR and NMR. In addition, the polyamic acid having a solid content is decomposed with a strong alkaline aqueous solution such as KOH or NaOH, and then extracted with an organic solvent and analyzed by GC, HPLC or GC-MS to identify the monomers used.

The liquid crystal aligning agent of the present invention may further contain, in addition to the polymer component A, a polymer component B which is a polyamic acid obtained by reacting other diamine other than the diamine (1) with an acid anhydride. This is a form of so-called polymer blend. When the polymer component B is blended, its preferable content is 1 to 50% by weight, more preferably 2 to 30% by weight, based on the total amount of the polymer in the liquid crystal aligning agent. By setting to such a range, both the manifestation of the effect of the present invention and the adjustment of the orientation can be achieved.

The liquid crystal aligning agent of the present invention may further contain one or two or more other components in addition to the above-mentioned polyamic acid. For example, the liquid crystal aligning agent of the present invention may further contain an epoxy compound from the viewpoint of improving the durability in the liquid crystal alignment film.

In the present invention, the content of the epoxy compound in the liquid crystal aligning agent is not particularly limited. When an epoxy compound is used, the liquid crystal alignment layer formed from the liquid crystal aligning agent is preferably 0.1 to 40% by weight based on the total amount of the liquid crystal alignment agent, From the viewpoint of improving the durability such that the film is hardly removed by the film, and more preferably 0.2 to 30% by weight.

Examples of the epoxy compound include a copolymer of a monomer having an oxirane and another monomer with a monomer of a bisphenol A type epoxy resin, a glycidyl ester type epoxy resin, an alicyclic epoxy resin, an oxirane, (E1) to (E3), (E5), and a compound represented by the formula (E4).

(N in the formula (E4) represents an integer of 0 to 10).

Specific examples of the epoxy resin include Epikote 807, Epikote 815, Epikote 825 and Epikote 827. Examples of the compound represented by the formula (E4) include Epikote 828, Epikote 190P, Epikote 191P, Epikote 1004, Epikote 1256, and Araldite CY177. Epikote is a trade name of JAPAN EPOXY RESIN CO., LTD. (Currently available as a product of Mitsubishi Kagaku jER series). Aralidite is a trade name of Nihon Chiba Kogyo Co., Ltd. (now available from Hanshan Japan Co., Ltd.).

As the compound represented by the formula (E1), Araldite CY184 can be mentioned. Examples of the compound represented by the formula (E2) include "Sucroxide 2021P" and "EHPE-3150" available from Daicel Chemical Industries, Ltd. As the compound represented by the formula (E3), trade name "Techmore VG3101L" of Mitsui Chemicals, Inc. can be mentioned. As the compound represented by the formula (E5), 4,4-methylene bis (N, N-diglycidylatilline) available from Sigma-Aldrich Co. can be mentioned.

Of these, Epikote 828 which is a compound represented by the formula (E4) (mixture of compounds in which n = 0 to 4), Araldite CY184 which is a compound represented by the formula (E1), and a compound represented by the formula (N, N-diglycidyl aniline), which is a compound represented by the formula (E5), is used in the liquid crystal alignment layer, From the viewpoint of improving transparency and flatness.

The liquid crystal aligning agent of the present invention may further contain one or more kinds of coupling agents such as a silane coupling agent, a titanium-based coupling agent, and an amino silicone compound from the viewpoint of improving the adhesion to the substrate. Examples of the aminosilicon compound include vinyltrimethoxysilane, vinyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) Aminopropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltriethoxysilane, methaminophenyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxy Silane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, N- (1,3-dimethylbutylidene) -3- Propylamine, and N, N'-bis [3- (trimethoxysilyl) propyl] ethylenediamine. . When the coupling agent is used, the content thereof is preferably 0.01 to 20% by weight in the liquid crystal aligning agent.

The liquid crystal aligning agent of the present invention may further contain other polymer components such as polyester, acrylic acid polymer, and acrylate polymer within the range not impairing the characteristics of the present invention. As other polymer components, polyamides or polyamideimides having other diamines as the diamine raw materials described above may be used. At this time, the preferable ratio of the other polymer components is 0.2 or less by weight relative to the above-mentioned polyamic acid having a residue of the diamine (1) in the constituent unit.

The liquid crystal aligning agent of the present invention may further contain a surfactant for its purpose from the viewpoint of improving the coatability of the liquid crystal aligning agent and may further contain an antistatic agent for improving the antistatic property of the liquid crystal aligning agent May be further contained.

The liquid crystal aligning agent of the present invention may further contain a solvent from the viewpoint of adjusting the coating property of the liquid crystal aligning agent and the concentration of the polymer component. The selection conditions of the solvent may be determined in consideration of the solubility of the polymer component, economic efficiency, environmental safety, etc. Specifically, a solvent commonly used in the production process of the polymer component such as polyamic acid, soluble polyimide, You can choose. This solvent may be used alone or in combination with two or more solvents.

Examples of the aprotic polar organic solvent which is a hydrophilic solvent for the polyamic acid include N-methyl-2-pyrrolidone, dimethylimidazolidinone, N-methylcaprolactam, N-methylpropionamide, N, N, N-dimethylformamide, N, N-diethylformamide, diethylacetamide, and lactones such as? -Butyrolactone.

Examples of the solvent other than the aprotic polar organic solvent for improving the coating property include alkyl lactates such as 3-methyl-3-methoxybutanol, tetralin, isophorone, ethylene glycol monoalkyl ether (e.g., Ethylene glycol monobutyl ether), diethylene glycol monoalkyl ethers (e.g., diethylene glycol monoethyl ether), triethylene glycol monoalkyl ethers, propylene glycol monoalkyl ethers (e.g., propylene glycol monobutyl ether), malonic acid dialkyl (For example, diethyl malonate), dipropylene glycol monoalkyl ethers (e.g., dipropylene glycol monomethyl ether), and ester compounds of these glycol monoalkyl ethers (e.g., acetate).

Among these, preferred solvents are N-methyl-2-pyrrolidone, dimethylimidazolidinone,? -Butyrolactone, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monobutyl ether and dipropylene glycol Monomethyl ether.

In the present invention, the preferred concentration of the polymer component in the liquid crystal aligning agent is 0.1 to 40% by weight. When this liquid crystal aligning agent is applied to a substrate, it may be necessary to dilute the polymer component contained in advance with a solvent in order to adjust the film thickness. If the concentration of the polymer component is 40% by weight or less, the diluting solvent can be easily mixed and it is considered that the viscosity adjustment for adjusting the film thickness is not hindered.

The concentration of the polymer component in the liquid crystal aligning agent may be adjusted depending on the application method of the liquid crystal aligning agent. When the application method of the liquid crystal aligning agent is a spinner method or a printing method, the concentration of the polymer component is usually set to 10 wt% or less in order to maintain good film thickness. In some other coating methods, for example, the dipping method and the ink-jet method, there may be a case where the concentration is lower. On the other hand, if the concentration of the polymer component is 0.1% by weight or more, the film thickness of the resulting liquid crystal alignment film tends to be optimal. Therefore, the concentration of the polymer component is 0.1% by weight or more, and preferably 0.5 to 10% by weight in the conventional spinner method and printing method. However, depending on the application method of the liquid crystal aligning agent, it may be used in a leaner concentration.

On the other hand, when used in the production of a liquid crystal alignment film, the viscosity of the liquid crystal aligning agent of the present invention can be determined by means or a method of forming the film of the liquid crystal aligning agent. For example, when a film of a liquid crystal aligning agent is formed by using a printing machine, it is preferably 5 mPa · s or more from the viewpoint of obtaining a sufficient film thickness, 100 mPa · s or less from the viewpoint of suppressing printing unevenness, And preferably 10 to 80 mPa · s. When the liquid crystal aligning agent is applied by spin coating to form a liquid crystal aligning agent film, it is preferably 5 to 200 mPa · s, more preferably 10 to 100 mPa · s, from the same viewpoint. The viscosity of the liquid crystal aligning agent can be reduced by curing accompanied by dilution or agitation with a solvent.

The liquid crystal alignment film of the present invention is obtained from the above-described liquid crystal aligning agent of the present invention. The liquid crystal alignment film of the present invention can be obtained by a conventional method for producing a liquid crystal alignment film from a liquid crystal aligning agent. For example, the liquid crystal alignment film of the present invention can be produced by a process of forming a coating film of the liquid crystal aligning agent of the present invention, Followed by heating and firing. This coating film can be formed by applying the liquid crystal aligning agent of the present invention to a substrate in a liquid crystal display element in the same manner as in the production of an ordinary liquid crystal alignment film. As a coating method, generally known methods such as a spinner method, a printing method, a dipping method, a dropping method, and an ink jet method can be applied. As the substrate, an electrode such as an ITO (Indium Tin Oxide) electrode or a glass substrate on which a color filter or the like may be provided may be used.

The firing of the coating film is carried out under the conditions necessary for dehydration and cyclization of the polyamic acid. As the firing method, a method of heating in an oven or an infrared furnace, a method of heating on a hot plate, or the like can be applied. It is generally preferable to carry out the reaction at a temperature of about 150 to 300 DEG C for 1 minute to 3 hours.

In the liquid crystal alignment film of the present invention, if necessary, the film obtained in the above firing step may be subjected to rubbing treatment. This rubbing treatment can be carried out in the same manner as in the rubbing treatment for the alignment treatment of an ordinary liquid crystal alignment film, provided that sufficient retardation can be obtained in the liquid crystal alignment film of the present invention. Particularly preferable conditions are a pad press-in amount of 0.2 to 0.8 mm, a stage moving speed of 5 to 250 mm / sec, and a roller rotation speed of 500 to 2,000 rpm. As the alignment treatment method of the liquid crystal alignment film, besides the rubbing method, a photo alignment method, a transfer method and the like are generally known. Within the range in which the effect of the present invention can be obtained, these other orientation treatment methods may be used in combination in the rubbing treatment.

The liquid crystal alignment film of the present invention is preferably obtained also by a method including a process other than the process described above. Examples of such another process include a step of drying the coating film, a step of cleaning the film before and after the rubbing treatment with a cleaning liquid, and the like.

In this drying step, as in the above-mentioned firing step, a method of heating in an oven or infrared, a method of heating on a hot plate, and the like are generally known. These methods can be similarly applied to the drying step. The drying process is preferably performed at a temperature within a range in which evaporation of the solvent is possible, and more preferably at a relatively low temperature relative to the temperature in the baking process.

Examples of the cleaning method of the liquid crystal alignment film by the cleaning liquid before and after the alignment treatment include brushing, jet spraying, steam cleaning, ultrasonic cleaning, and the like. These methods may be performed alone or in combination. Examples of the cleaning liquid include pure water or various alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, aromatic hydrocarbons such as benzene, toluene and xylene, halogen solvents such as methylene chloride, and ketones such as acetone and methyl ethyl ketone But are not limited to these. Needless to say, these cleaning liquids are sufficiently purified so that a small amount of impurities are used. Such a cleaning method can also be applied to the cleaning step in the formation of the liquid crystal alignment film of the present invention.

The thickness of the liquid crystal alignment film of the present invention is not particularly limited, but is preferably 10 to 300 nm, more preferably 30 to 150 nm. The film thickness of the liquid crystal alignment film of the present invention can be measured by a known film thickness measuring apparatus such as a step system or an ellipsometer.

A liquid crystal display element of the present invention is a liquid crystal display element in which a pair of substrates obtained by forming a liquid crystal alignment film of the present invention on at least one side are faced to each other with a spacer interposed therebetween in a liquid crystal alignment film, Layer. The above-mentioned ITO electrode-attached glass substrate can be used for this substrate. The production of the liquid crystal display device of the present invention may include a new process such as attaching a polarizing film to the substrate if necessary.

The liquid crystal composition is not particularly limited, and various liquid crystal compositions having a positive or negative dielectric anisotropy may be used. Preferred liquid crystal compositions having a positive dielectric anisotropy include those described in Japanese Patent No. 3086228, Japanese Patent No. 2635435, Japanese Patent Application Publication No. Hei 5-501735, Japanese Patent Application Laid-Open No. 8-157826, Japanese Patent Japanese Patent Application Laid-open No. Hei 8-231960, Japanese Patent Application Laid-open No. 9-241644 (EP 885272A1 specification), Japanese Patent Application Laid-open No. 9-302346 (EP 806466A1 specification), Japanese Patent Application Laid- Japanese Patent Application Laid-Open No. 9-235552, Japanese Patent Application Laid-Open No. 9-255956, Japanese Patent Application Laid-Open No. 9-241643 (EP 885271A1 specification), Japanese Patent Application Laid- ), Japanese Patent Application Laid-Open No. 10-204016 (specification of EP 844229A1), Japanese Patent Application Laid-open No. 10-204436, Japanese Patent Application Laid-open No. 10-231482, Japanese Patent Application Laid- 087040, Japan Heochulwon may be a liquid crystal composition that is disclosed in Laid-open No. 2001-48822 discloses.

Preferred liquid crystal compositions having a negative dielectric anisotropy include those disclosed in Japanese Patent Application Laid-open Nos. 57-114532, 2-4725, 4-224885, and Japanese Patent Application Laid Open Japanese Patent Application Laid-Open No. 8-40953, Japanese Patent Application Laid-Open No. 8-104869, Japanese Patent Application Laid-Open No. 10-168076, Japanese Patent Application Laid-Open No. 10-168453, Japanese Patent Application Laid- 10-236989, Japanese Patent Application Laid-Open No. 10-236990, Japanese Patent Application Laid-Open No. 10-236992, Japanese Patent Application Laid-Open No. 10-236993, Japanese Patent Application Laid- Japanese Patent Application Laid-open No. Hei 10-237000, Japanese Patent Application Laid-open No. Hei 10-237024, Japanese Patent Application Laid-open No. Hei 10-237035 Bulletin, Japanese patent application Open No. 10-237075, Japanese Patent Application Laid-open No. 10-237076, Japanese Patent Application Laid-open No. 10-237448 (EP 967261A1 specification), Japanese Patent Application Laid-Open No. 10-287874, Japanese Patent Application Laid-Open Nos. 10-287875, 10-291945, 11-029581, 11-080049, and Japanese Patent Application Liquid crystal compositions disclosed in Japanese Patent Application Laid-Open No. 2000-256307, Japanese Patent Application Laid-Open No. 2001-019965, Japanese Patent Application Laid-Open No. 2001-072626, Japanese Patent Application Laid-Open No. 2001-192657, have.

One or more optically active compounds may be added to the liquid crystal composition having a positive or negative dielectric anisotropy.

The liquid crystal display element of the present invention can form liquid crystal display elements for various electric field systems. The liquid crystal display element for such an electric field system includes a liquid crystal display element for a transverse electric field system in which the electrode applies a voltage to the liquid crystal layer in the horizontal direction with respect to the surface of the substrate, And a liquid crystal display element for an aging system in which the electrode applies a voltage to the liquid crystal layer.

Since the liquid crystal display element for the transverse electric field system does not need to exhibit a comparatively large pretilt angle, an alignment film of the liquid crystal aligning agent of the present invention obtained from a diamine containing no diamine having a side chain is preferably used.

Since the liquid crystal display element for the conventional system requires a relatively large pretilt angle, a liquid crystal alignment film using a polymer A obtained from a diamine mixture containing a diamine represented by the general formula (1) and a diamine having a side chain Is preferably used. When the polymer A is a polymer obtained from a mixture of a diamine represented by the general formula (1) and a diamine having no side chain, a diamine having a side chain or a diamine mixture containing a diamine having a side chain and a diamine having no side chain Is preferably used as the alignment film of the liquid crystal aligning agent of the present invention.

As described above, the liquid crystal alignment film produced using the liquid crystal aligning agent of the present invention as a raw material can be applied to liquid crystal display devices of various display driving systems by appropriately selecting the polymer as a raw material thereof.

[Example]

The liquid crystal aligning agent and liquid crystal display element obtained by using the polymer of the present invention will be described in detail by the following examples, but the present invention is not limited to these examples. In the examples, GPC was used for measurement of the molecular weight, polystyrene was used as the standard solution, and DMF was used as the eluent. In the following embodiments, the unit liters of the volume are denoted by L. Thus, mL means milliliter.

Hereinafter, an evaluation method of a liquid crystal display element used in the examples will be described.

(1) Voltage maintenance ratio (VHR)

Measurement was carried out at a frequency of 30 Hz, a voltage of ± 5 V, and a measurement temperature of 60 ° C. using the "6254-type liquid crystal physical property evaluation system" manufactured by Toyo Technica Co., The larger the value, the better the electrical characteristics.

(2) Measurement of long-term high-temperature reliability

With respect to the liquid crystal display device manufactured, the voltage holding ratio was obtained with a lapse of time, and the holding characteristics were evaluated. As a test method of the holding characteristics, the liquid crystal display device was left in an atmosphere at a temperature of 100 占 폚 for 500 hours, and the voltage sustained rate was measured by taking out the liquid crystal display device over time. The lower the voltage holding ratio after heating at 100 占 폚 as compared with the initial voltage holding ratio is, the better the long-term high temperature reliability is.

(3) Measurement of UV resistance

The liquid crystal display device manufactured was irradiated with light on the entire surface of the device using a metal halide lamp as a light source. By using a filter, the irradiation wavelength was set to a wavelength range of 300-450 nm and the irradiation energy was 8 J / cm 2. The lower the decrease in the voltage holding ratio after light irradiation compared with the initial voltage holding ratio, the better the UV resistance.

(4) Pretilt angle (Pt angle)

(OMS-CA3), manufactured by Chuo Seiki Co., Ltd., at room temperature.

The names of acid anhydrides, diamines and solvents used in Examples and Comparative Examples are denoted by the abbreviation. There are cases where this abbreviation is used in the following description.

<Acid anhydride>

1,2,3,4-Cyclobutane tetracarboxylic acid dianhydride (acid anhydride (T6)): CBDA

Pyromellitic dianhydride (acid anhydride (T1)): PMDA

1,2,3,4-butanetetracarboxylic acid dianhydride (acid anhydride (T7)): BTDA

4,4'-ethane-1,2-diyl) bis (morpholine-2,6-dione): EDDA

<Diamine>

2,4-diamino-6-phenyl-1,3,5-triazine (diamine (1-9)): DPTA

2-vinyl-4,6-diamino-1,3,5-triazine (diamine (1-7)): VDTA

2,4-diamino-6- (methacryloyloxy) ethyl-1,3,5-triazine (diamine (1-13)): ETZ

2,4-diamino-6-diallylamino-1,3,5-triazine (diamine (1-20)): AAZ

4,4'-diaminodiphenylmethane (diamine (3-1)): DDM

2,2'-dimethyl-4,4'-diaminodiphenylmethane (diamine (3-21)): MBMB

Phenyl] methyl] -1,3-diaminobenzene (diamine (6- (5-1)): Synthesis of PBPB (4-aminophenyl)

Compound: 1,1-Bis [4- (4-aminophenoxy) phenyl- (4-trans-4-n-pentylcyclohexyl) cyclohexane (diamine (5-23)

1,2-bis (4-aminophenyl) ethane (diamine (3-2)): DET

<Solvent>

N-methyl-2-pyrrolidone: NMP

Butyl cellosolve: BC

[Synthesis Example 1]

&Lt; Preparation of Composition P1 for Liquid Crystal Alignment Film (Varnish P1)

0.298 g of DPTA, 2.883 g of MBMB, 0.689 g of PBPB and 58.3 mL of dehydrated NMP were placed in a 200 mL four-necked flask equipped with a thermometer, a stirrer, a feed inlet and a nitrogen gas inlet, and dissolved under stirring in a dry nitrogen stream . While maintaining the temperature of the reaction system at 5 占 폚, 2.50 g of CBDA and 0.631 g of BTDA were added and reacted for 30 hours. 36.6 mL of BC was added to prepare a varnish of polyamic acid having a polymer component concentration of 7 wt%. When the reaction temperature rises due to the reaction heat during the reaction of the raw materials, the reaction temperature is controlled to be about 70 캜 or lower and the reaction is carried out.

The weight average molecular weight of the obtained polyamic acid was 108,500. The weight average molecular weight was obtained by diluting the obtained polyamic acid with a phosphoric acid-DMF mixed solution (phosphoric acid / DMF = 0.6 / 100: weight ratio) such that the concentration of polyamic acid was about 1% by weight, and then diluted with 2695 separation module, 2414 differential refractometer Manufactured by Mitsui Chemicals, Inc.), measuring the GPC method using the mixed solution as a developing agent, and calculating the polystyrene conversion. The column was measured under the conditions of a column temperature of 40 DEG C and a flow rate of 0.35 mL / min using HSPgel RT MB-M (manufactured by Waters).

The varnish obtained as described above was diluted with a mixed solvent of NMP / BC (weight ratio 50/50) to adjust the concentration of the entire polymer component to 3 wt%, thereby obtaining a varnish P1 for application.

[Synthesis Examples 2 to 18]

<Preparation of various varnishes>

Varnishes P2 to P18 having a total polymer component concentration of 3% by weight were prepared in the same manner as in the case of the varnish P1 except that the raw materials shown in Table 1 were used in the respective molar ratios. The weight average molecular weight of the obtained polyamic acid is shown in Table 1 together with the results of Synthesis Example 1.

[Example 1]

&Lt; Production of cell a for voltage maintaining ratio measurement >

The varnish P1 obtained in Synthesis Example 1 was applied onto a glass substrate with an ITO electrode by a spinner. The application condition was 1,700 rpm for 15 seconds. The substrate coated with the varnish P1 was prebaked at 80 캜 for about 5 minutes and then subjected to a heat treatment at 200 캜 for 40 minutes to obtain a substrate for liquid crystal alignment in which a liquid crystal alignment film having a thickness of about 70 nm was formed. This substrate was ultrasonically cleaned in ultrapure water for 5 minutes and then dried in an oven at 120 ° C for 30 minutes. A gap of 4 mu m was spread on the other glass substrate with an ITO electrode and the glass substrate with the other ITO electrode was sealed with an epoxy curing agent to prepare a cell having a gap of 4 mu m. A liquid crystal material was injected into the cell, and the injection port was sealed with a photo-curing agent. Then, the cell was subjected to a heat treatment at 110 DEG C for 30 minutes to obtain cell a for measuring pre-tilt angle and voltage maintenance ratio. The composition of the liquid crystal composition A used as the liquid crystal material is shown below. The NI point of this composition was 75.4 DEG C and the birefringence was 0.081.

<Liquid crystal composition A>

The measurement cell a was used to measure the pretilt angle, voltage retention rate, long-term high-temperature reliability, and UV resistance. The measurement results are shown in Table 2.

[Examples 2 to 8]

Using the varnish P2 obtained in Synthesis Examples 2 and 7 to 12 and the varnish P7 to 12, a measurement cell a was prepared in the same manner as in Example 1, and the pretilt angle, voltage retention, long term high temperature reliability and UV resistance were measured. The measurement results are shown in Table 2.

[Comparative Example 1]

Using the varnish P3 obtained in Synthesis Example 3, a measuring cell a was prepared in the same manner as in Example 1, and the pretilt angle, voltage holding ratio, long-term high temperature reliability and UV resistance were measured. The measurement results are shown in Table 2.

[Example 9]

The varnish P4 obtained in Synthesis Example 4 was applied onto a glass substrate with an ITO electrode by a spinner. The application condition was 1,700 rpm for 15 seconds. The substrate coated with the varnish P4 was prebaked at 80 캜 for about 3 minutes and then subjected to a heat treatment at 230 캜 for 20 minutes to obtain a substrate on which a liquid crystal alignment film having a film thickness of about 70 nm was formed. Using this rubbing treatment apparatus manufactured by Iinuma Gage Seisakusho Co., Ltd., the liquid crystal alignment film was irradiated with ultraviolet light at an ultraviolet light irradiation amount of 0.40 mm on the rubbing cloth (mother-of-pearl 1.8 mm: rayon), a stage moving speed of 60 mm / sec, Rubbing treatment was carried out under the condition of 1,000 rpm to obtain a liquid crystal interposing substrate. This substrate was ultrasonically cleaned in ultrapure water for 5 minutes and then dried in an oven at 120 ° C for 30 minutes. An antiparallel cell having a gap of 7 mu m was prepared by applying a gapping agent of 7 mu m to the other glass substrate with an ITO electrode and adhering it to the other glass substrate with an ITO electrode with an epoxy curing agent. A liquid crystal material was injected into the cell, and the injection port was sealed with a photo-curing agent. Subsequently, heat treatment was performed at 110 占 폚 for 30 minutes to obtain cell b for measuring pre-tilt angle and voltage maintenance ratio. The composition of the liquid crystal composition B used as the liquid crystal material is shown below. The NI point of this composition was 100.0 占 폚 and the birefringence was 0.093.

<Liquid Crystal Composition B>

The pre-tilt angle, voltage retention rate, long-term high-temperature reliability and UV resistance were measured using the obtained measurement cell b. The measurement results are shown in Table 3.

[Examples 10 to 16]

Measurement cell b was prepared in the same manner as in Example 9 using varnish P5 and varnish P13 to P18 obtained in Synthesis Example (5) and Synthesis Examples 13 to 18, and evaluated for pretilt angle, voltage retention, Were measured. The measurement results are shown in Table 3.

[Comparative Example 2]

Using the varnish P6 obtained in Synthesis Example 6, a measurement cell b was prepared in the same manner as in Example 9, and the pretilt angle, voltage retention rate, long-term high temperature reliability and UV resistance were measured. The measurement results are shown in Table 3.

[Synthesis Examples 19 to 22]

The raw materials shown in Table 4 were used at respective molar ratios to obtain a polyamic acid solution having a polymer concentration of 7% by weight in accordance with Synthesis Example 1. Table 4 shows the weight average molecular weights of the obtained polyamic acid.

[Example 17]

A polyamic acid solution having a concentration of 7% by weight obtained in Synthesis Example 19 and a polyamic acid solution having a concentration of 7% by weight obtained in Synthesis Example 22 were mixed in a weight ratio of 10/90 (Synthesis Example 19 / Synthesis Example 22). This mixed solution was diluted with a mixed solvent of NMP / BC (weight ratio 50/50) to adjust the concentration of the entire polymer component to 3 wt%, thereby obtaining a varnish P19 for coating. Using this varnish P19, a measuring cell a was prepared in the same manner as in Example 1, and the voltage holding ratio, long-term high temperature reliability and UV resistance were measured. The measurement results are shown in Table 5.

[Example 18]

A polyamic acid solution having a concentration of 7% by weight obtained in Synthesis Example 20 and a polyamic acid solution having a concentration of 7% by weight obtained in Synthesis Example 22 were mixed in a weight ratio of 10/90 (Synthesis Example 20 / Synthesis Example 22). This mixed solution was diluted with a mixed solvent of NMP / BC (weight ratio 50/50) to adjust the concentration of the entire polymer component to 3 wt%, and used as a varnish P20 for application. Using this varnish P20, a measuring cell a was prepared in the same manner as in Example 1, and the voltage holding ratio, long-term high temperature reliability and UV resistance were measured. The measurement results are shown in Table 5.

[Comparative Example 3]

A polyamic acid solution having a concentration of 7% by weight obtained in Synthesis Example 21 and a polyamic acid solution having a concentration of 7% by weight obtained in Synthesis Example 22 were mixed in a weight ratio of 10/90 (Synthesis Example 21 / Synthesis Example 22). The mixed solution was diluted with a mixed solvent of NMP / BC (weight ratio 50/50) to adjust the concentration of the entire polymer component to 3 wt%, thereby obtaining a varnish P21 for coating. Using this varnish P21, a measuring cell a was prepared in the same manner as in Example 1, and the voltage holding ratio, long-term high temperature reliability and UV resistance were measured. The measurement results are shown in Table 5.

As is clear from the results of Examples 1 to 18 and Comparative Examples 1 to 3, the use of the polyamic acid having the diamine residue of the triazine skeleton in the constituent unit enables high voltage retention, long-term high-temperature reliability (thermal reliability), and UV resistance Light resistance) can be produced at the same time.

Claims (9)

A polyamic acid or a derivative thereof obtained by reacting a diamine mixture comprising at least one of the diamines represented by the formula (1) and at least one other diamine with a tetracarboxylic acid dianhydride is referred to as a polymer component A;
The diamine compound represented by the formula (1) in the diamine mixture is contained in an amount of 5 to 30 mol% based on the total amount of the diamine mixture, and the polymer component A has a weight average molecular weight of 20,000 to 200,000;
A polyamic acid or a derivative thereof obtained by reacting at least one of the other diamines with a tetracarboxylic dianhydride is referred to as a polymer component B;
A liquid crystal aligning agent containing a polymer component A as an essential component and containing a polymer component B as an optional component:

In formula (1), R ¹ is hydrogen, -OH, -NH-C ₄ H ₉ , -N (CH ₃ ) ₂ , -N (C ₂ H ₅ ) ₂ , -N (CH ₂ CH═CH ₂ ) ₂ , -NH-CH ₂ CH = CH ₂ , halogen, alkyl of 1 to 20 carbon atoms, alkoxy of 1 to 20 carbon atoms, alkenyl of 2 to 20 carbon atoms, aryl of 6 to 20 carbon atoms, aryl of 7 to 20 carbon atoms Alkyl, or the following structure:

The method according to claim 1,
And R &lt; ^{1 &gt;} is vinyl or phenyl. 3. The method according to claim 1 or 2,
Wherein the tetracarboxylic dianhydride is at least one of compounds represented by the following formulas (T1) to (T8): liquid crystal aligning agent:

The method of claim 3,
Wherein the tetracarboxylic dianhydride is at least one compound represented by the formula (T1), the formula (T6) and the formula (T7). 3. The method according to claim 1 or 2,
Wherein the other diamine is a diamine selected from the group of the compounds represented by the formulas (3) to (6), the liquid crystal aligning agent:

In formula (3), Y is alkylene having 1 to 7 carbon atoms, and arbitrary -CH ₂ - of the alkylene may be substituted with -O- or -S-; R ² is independently alkyl of 1 to 3 carbon atoms; k is independently 0 or 1;

In formula (4), X ¹ is independently -CH ₂ - or -O-; X ² is alkylene having 1 to 8 carbon atoms, and any hydrogen of the alkylene may be substituted with methyl or -CF ₃ ;

In formula (5), X ¹ is independently alkylene having 1 to 6 carbon atoms or -O-; X ³ is a single bond or alkylene having 1 to 3 carbon atoms, and the ring T is 1,4-phenylene or 1,4-cyclohexylene, h is 0 or 1; R ³ is hydrogen or alkyl having 1 to 30 carbon atoms, and any -CH ₂ - of the alkyl may be substituted with -O-, -CH = CH- or -C≡C- when the number of carbon atoms is 2 to 30 ;

In formula (6), A ¹ represents a single bond, -O-, -COO-, -OCO-, -CO-, -CONH-, -NHCO-, alkylene of 1 to 4 carbon atoms or 1,4- Hexylene; R ⁴ is a group having a steroid skeleton, or a group represented by formula (A)

(Wherein A ² and A ³ are independently a single bond, -O-, -COO-, -OCO-, -CONH-, -NHCO-, -CH = CH- or alkylene having 1 to 12 carbon atoms;
R ⁵ and R ⁶ are independently fluorine or methyl, f and g are independently integers of from 0 to 2; The ring S can be selected from the group consisting of 1,4-phenylene, 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, pyrimidine- 1,4-diyl, naphthalene-1,5-diyl, naphthalene-2,6-diyl, naphthalene-2,7-diyl, or anthracene-9,10-diyl; R ⁷ is H, F, -OH, fluorinated alkyl, alkyl of 1 to 30 carbon atoms, 1 to 30 carbon atoms alkoxy of 1 to 30 carbon _{atoms, -CN, -OCH 2 F, -OCHF} 2 or -OCF _3, and;
c, d and e are independently integers of from 0 to 3, with c + d + e? 1; When e is 2 or 3, the plurality of rings S may all be the same ring or may be composed of at least two different rings. 3. The method according to claim 1 or 2,
A liquid crystal aligning agent containing only a polymer component A which is a polyamic acid obtained by reacting a diamine mixture comprising at least one of the diamines represented by the formula (1) and at least one of other diamines with a tetracarboxylic dianhydride or a derivative thereof. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 1 or 2. A liquid crystal display element comprising the liquid crystal alignment film according to claim 7. delete