JP7081488B2 - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Description

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film using the same, 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 orienting a liquid crystal in a certain direction. Currently, the main liquid crystal alignment film used industrially is formed from a liquid crystal alignment agent consisting of a polyamic acid (also referred to as polyamic acid) which is a polyimide precursor or a solution of polyimide. Specifically, it is obtained by applying a liquid crystal alignment agent to a substrate, heating and firing, and then performing a liquid crystal alignment treatment.

Conventionally, the surface treatment by rubbing is mainly performed as the liquid crystal alignment treatment, but in the rubbing treatment, it is usually difficult to perform a highly uniform alignment treatment, and the liquid crystal alignment is poorly aligned or the liquid crystal alignment film is defective. It may occur, resulting in display defects, dust generation, and other problems. In recent years, there has been a tendency for the area of the substrate to increase and the unevenness to increase due to the increase in size, high definition, low cost, etc. of the substrate used for the panel, and when forming an alignment film on such a substrate, rubbing is performed. The treatment also leaves room for improvement.

On the other hand, as an orientation treatment method that replaces the rubbing method, an orientation treatment using a photoreaction has been proposed. Specifically, a method of forming a polymer film having a specific site such as polyvinyl cinnamate on the surface of a substrate and irradiating it with polarized or unpolarized radiation to impart liquid crystal alignment ability ( Photoorientation method) is known. According to this method, uniform liquid crystal alignment can be realized without generating static electricity or dust, and the viewing angle can be improved by dividing the orientation (see Patent Documents 1 and 2).

Further, in a liquid crystal cell such as TN (Twisted Nematic) or STN (Super Twisted Nematic), the liquid crystal alignment film needs to have a function of tilting or aligning liquid crystal molecules with respect to a substrate surface at a predetermined angle (pre-tilt angle). .. A liquid crystal alignment film using an alkyl side chain, a side chain of a steroid skeleton, a polyamic acid having a side chain having a ring structure, a polyimide, or the like is known in order to develop a pretilt angle (Patent Documents 3, 4, and 3. 5). In the orientation process using light, the pretilt angle is usually given by irradiation with radiation whose incident direction to the substrate surface is inclined 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 Patent Application Laid-Open No. 05-043687 Japanese Patent Application Laid-Open No. 04-281427 Japanese Patent Application Laid-Open No. 02-223916

In recent years, liquid crystal display elements have been used in mobile electronic devices such as smartphones and mobile phones. In these applications, in order to secure a display surface as large as possible, there is a demand for a so-called narrow frame in which the width of the sealant used for adhesion between the substrates of the liquid crystal display element is made as narrow as possible. With the narrowing of the frame of the panel, the sealing agent used for manufacturing the liquid crystal display element is applied at a position close to the end of the liquid crystal alignment film or superimposed on the liquid crystal alignment film. However, since the liquid crystal alignment film usually has no or few polar groups, there is a problem that a covalent bond is not formed between the sealant and the liquid crystal alignment film, and the adhesion between the substrates is insufficient. .. In such a case, especially when used under high temperature and high humidity conditions, water tends to be mixed between the sealant and the liquid crystal alignment film, and there arises a problem that display unevenness occurs near the frame of the liquid crystal display element. .. Therefore, it is necessary to improve the adhesiveness (adhesion) between the liquid crystal alignment film and the sealant or the substrate. On the other hand, it is necessary to improve the adhesiveness of the liquid crystal alignment film with the sealant and the substrate without deteriorating the liquid crystal alignment and electrical characteristics of the liquid crystal alignment film.
A main object of the present invention is to provide a liquid crystal alignment agent capable of improving the adhesion between a liquid crystal alignment film and a sealing agent or a substrate without deteriorating the liquid crystal alignment and electrical characteristics.

式中、Ａは、温度１５０～３００℃の加熱により水素原子に置き換わる熱脱離性基を表す。ベンゼン環の有する水素原子は、炭素数１～５のアルキル基若しくはアルコキシ基又はハロゲン基により置換されていてもよい。ｍは１～１８の整数であり、ｍが３～１８である場合は、任意の炭素―炭素結合間に－Ｏ－が存在していてもよい。ｎは２～１８の整数であり、ｎが３～１８である場合は、任意の炭素―炭素結合間に－Ｏ－が存在していてもよい。＊は結合手を表す。The present inventor has completed the present invention as a result of diligent research to achieve the above object.
The present invention has a diamine component containing a diamine having the structure of the following formula [1], a diamine having the structure of the following formula [2], and a diamine having the structure of the following formula [3], and a tetracarboxylic acid dianhydride component. The gist is a liquid crystal aligning agent characterized by containing at least one polymer selected from the group consisting of a polyamic acid obtained by the reaction with and a polyimide obtained by imidizing the polyamic acid.

In the formula, A represents a thermally desorbing group that replaces a hydrogen atom by heating at a temperature of 150 to 300 ° C. The hydrogen atom of the benzene ring may be substituted with an alkyl group having 1 to 5 carbon atoms, an alkoxy group or a halogen group. m is an integer of 1 to 18, and if m is 3 to 18, —O— may be present between any carbon-carbon bonds. n is an integer of 2 to 18, and if n is 3 to 18, —O— may be present between any carbon-carbon bonds. * Represents a bond.

The liquid crystal alignment agent of the present invention can improve the sealing adhesion in a liquid crystal display element or the like to be sealed with a sealing agent, and the obtained liquid crystal alignment film is not colored blackish brown and the transparency is not lost. Good characteristics such as LCD and LCD angle.

The liquid crystal aligning agent of the present invention has a diamine having a structure represented by the above formula [1] (hereinafter, also referred to as a specific diamine 1) and a diamine having a structure represented by the above formula [2] (hereinafter, a specific diamine 2). Also referred to as), and a polyamic acid obtained by reacting a diamine component containing a diamine having a structure represented by the above formula [3] (hereinafter, also referred to as specific diamine 3) with a tetracarboxylic acid dianhydride component. And at least one polymer selected from the group consisting of polyimide obtained by imidizing the polyamic acid.

式［１］中、Ａは、温度１５０～３００℃の加熱により水素に置き換わる熱脱離性基である。熱脱離性基は、好ましくは１７０～３００℃、特に好ましくは１８０～２５０℃で脱離すればさらに好適である。＊は結合手を表す。<Specific diamine 1>
The specific diamine 1 contained in the liquid crystal alignment agent of the present invention is a diamine having a structure represented by the following formula [1].

In the formula [1], A is a thermally desorbing group that replaces hydrogen by heating at a temperature of 150 to 300 ° C. The thermally desorbable group is more preferably desorbed at 170 to 300 ° C, particularly preferably 180 to 250 ° C. * Represents a bond.

The thermally desorbing group is a carbamate-based organic represented by a benzyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, an allyloxycarbonyl group, a tertiary butoxycarbonyl group (also referred to as a Boc group), and the like. The group is mentioned. A Boc group or a 9-fluorenylmethoxycarbonyl group is particularly preferable because it is a gas that is desorbing efficiently, has a relatively low temperature, and is harmless during desorption.

The amino group contained in the specific diamine is preferably a primary amino group, but may be a secondary amino group. In the case of a secondary amino group, an alkyl group having a relatively small molecular weight such as a methyl group, an ethyl group, a propyl group or a butyl group is replaced with an amino group.
The hydrogen atom of the benzene ring in the formula [1] is arbitrarily 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 a chlorine atom, a bromine atom or a fluorine atom. It may have been.
Preferred specific examples of the diamine represented by the formula [1] include the following diamines. Boc in the formula represents a tert-butoxycarbonyl group.

式中、ｍは、１～１８の整数であり、好ましくは、２～１８の整数である。また、ｍが３～１８の整数である場合、任意の炭素―炭素結合間に－Ｏ－が存在していてもよい。＊は他の原子との結合手を表す。
式［２］におけるベンゼン環の有する水素原子は、炭素数１～５、好ましくは１～３のアルキル基若しくはアルコキシ基、又は、塩素原子、臭素原子、フッ素原子などのハロゲン基により、任意に置換されていてもよい。
式［２］で表わされる構造を有するジアミンの好ましい具体例としては、以下のジアミンが挙げられるがこれらに限定されない。<Specific diamine 2>
The specific diamine 2 contained in the liquid crystal alignment agent of the present invention is a diamine having a structure represented by the following formula [2].

In the formula, m is an integer of 1 to 18, preferably an integer of 2 to 18. Further, when m is an integer of 3 to 18, —O— may be present between any carbon-carbon bond. * Represents a bond with another atom.
The hydrogen atom of the benzene ring in the formula [2] is arbitrarily 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 a chlorine atom, a bromine atom or a fluorine atom. It may have been done.
Preferred specific examples of the diamine having the structure represented by the formula [2] include, but are not limited to, the following diamines.

式中、ｎは２～１８の整数であり、ｎが３～１８の整数である場合は、任意の炭素―炭素結合間に－Ｏ－が存在していてもよい。Ａの定義及びその好ましい範囲は、式［１］のＡと同様である。＊は結合手を表す。
式［３］におけるベンゼン環の有する水素原子は、炭素数１～５、好ましくは１～３のアルキル基若しくはアルコキシ基、又は、塩素原子、臭素原子、フッ素原子などのハロゲン基により、任意に置換されていてもよい。
式［３］で表わされるジアミンの好ましい具体例としては、以下のジアミンが挙げられるがこれらに限定されない。<Specific diamine 3>
The specific diamine 3 contained in the liquid crystal alignment agent of the present invention is a diamine having a structure represented by the following formula [3].

In the formula, n is an integer of 2 to 18, and if n is an integer of 3 to 18, —O— may be present between any carbon-carbon bonds. The definition of A and its preferable range are the same as those of A in the formula [1]. * Represents a bond.
The hydrogen atom of the benzene ring in the formula [3] is arbitrarily 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 a chlorine atom, a bromine atom or a fluorine atom. It may have been.
Preferred specific examples of the diamine represented by the formula [3] include, but are not limited to, the following diamines.

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

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

In the formula [7], the preferred group of Z ₁ is a group represented by the formula [7a] or the formula [7g] because of the polymerization reactivity and the ease of synthesis. Of these, the formula [7a] is most preferable.
When the tetracarboxylic acid dianhydride having the structure of the formula [7a] is used, it is preferably 20% by mass or more, more preferably 30% by mass or more of the total tetracarboxylic acid dianhydride component. be. When used in the production of polyimide precursors, the desired effect can be obtained. More preferably, it is 30% by mass or more. It is also possible to use all of the tetracarboxylic acid components used in the polyimide synthesis as 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 can be used.
Examples of the aliphatic tetracarboxylic acid dianhydride include 1,2,3,4-butanetetracarboxylic acid dianhydride. Examples of the alicyclic tetracarboxylic acid dianhydride include 1,2,3,4-cyclobutanetetracarboxylic 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-cyclobutanetetracarboxylic acid dianhydride 1,3-Diphenyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexane Tetracarboxylic acid dianhydride, 1,2,3,4-cycloheptane tetracarboxylic acid dianhydride, 2,3,4,5-tetracarboxylic acid dianhydride, 3,4-dicarboxy-1-cyclo Hexyl succinic hydride, 2,3,5-tricarboxycyclopentylacetic hydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalen succinic hydride, 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 dianhydride, bicyclo [4,4,0] decane-2,4,8,10-tetracarboxylic dianhydride, tricyclo [6] 3.0.0 <2,6>] Undecane-3,5,9,11-Tetracarboxylic acid dianhydride, 4- (2,5-dioxotetrachloride-3-yl) -1,2,3 , 4-Tetrahydrinaphthalene-1,2-dicarboxylic acid dianhydride, Bicyclo [2,2,2] Oct-7-en-2,3,5,6-tetracarboxylic acid dianhydride, 5- (2) , 5-Dioxotetrahydrofuryl) -3-methyl-3-cyclohexane-1,2-dicarboxylic acid dianhydride, Tetracyclo [6,2,1,1,0,2,7] Dodeca-4,5 , 9,10-Tetracarboxylic acid dianhydride, 3,5,6-tricarboxynorbornan-2: 3,5: 6 dicarboxylic acid dianhydride, and the like.
Other tetracarboxylic acid components include tetracarboxylic acid, tetracarboxylic acid dihalide, tetracarboxylic acid dianhydride, esterified product obtained by dialkyl esterifying the carboxylic acid group of tetracarboxylic acid, and dialkyl carboxylic acid group of tetracarboxylic acid dihalide. Examples thereof include esterified esterified products.

As the above-mentioned other tetracarboxylic acid components, one kind or two or more kinds can be used in consideration of the liquid crystal orientation, the voltage holding characteristic, the accumulated charge and the like of the liquid crystal alignment film formed.

<Polymer>
The liquid crystal alignment agent contains a polyamic acid and / or a polyimide obtained by imidizing the polyamic acid (hereinafter, also collectively referred to as a polymer).
Of these, the polymer of the present invention is an imidized polyamic acid obtained by reacting a diamine component containing specific diamines 1, 2 and 3 with a tetracarboxylic acid dianhydride component, and / or the polyamic acid. Means the polyimide obtained from the above. On the other hand, the polymer other than the present invention is a polyamic acid obtained by reacting a diamine component containing a diamine that is not protected by thermal desorption with a tetracarboxylic acid dianhydride component, and / or the polyamic acid. Means a polyimide obtained by imidizing.

<Polyamic acid>
The polyamic acid is obtained by reacting a diamine-containing diamine component with a tetracarboxylic acid dianhydride component.
The content ratio of the specific diamines 1, 2 and 3 in the diamine component for obtaining the polyamic acid which is the polymer of the present invention by the reaction with the tetracarboxylic acid dianhydride component is preferably 5 to 95 mol%. , More preferably 10-60 mol%.
Further, the total content ratio of the specific diamine 2 and the specific diamine 3 in the diamine component for obtaining the polyamic acid which is the polymer of the present invention is preferably 10 to 60 mol%, more preferably 20 to 40 mol%. The content ratio (molar ratio) of the specific diamine 2: the specific diamine 3 is preferably 10:90 to 90:10, more preferably 10:40 to 40:10.
In the present invention, the diamine component for obtaining a polyamic acid better satisfies various properties required for a liquid crystal alignment film, for example, a property of increasing the pretilt angle of a liquid crystal display and a property of increasing the vertical orientation of a liquid crystal display. Therefore, other diamines can be used together. When other diamines are used, the content of the other diamines is preferably 1 to 50 mol%, more preferably 5 to 30 mol% in the amine component.

Examples of the above other diamines include alicyclic diamines, aromatic-aliphatic diamines, heterocyclic diamines, and aliphatic diamines (excluding diamines represented by the formulas [1] to [3]). Be done.

Examples of alicyclic diamines are 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylamine, isophorone diamine. And so on.
Examples of aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1,4-diamino. -2-methoxybenzene, 2,5-diamino-p-xylene, 1,3-diamino-4-chlorobenzene, 3,5-diaminobenzoic acid, 1,4-diamino-2,5-dichlorobenzene, 4,4 '-Diamino-1,2-diphenylethane, 4,4'-diamino-2,2'-dimethylbibenzyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane , 4,4'-diamino-3,3'-dimethyldiphenylmethane, 2,2'-diaminostylben, 4,4'-diaminosylben, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4, 4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3- Bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,5-bis (4-aminophenoxy) benzoic acid, 4,4'-bis (4-aminophenoxy) bibenzyl, 2,2-bis [(4-aminophenoxy) methyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) Phenyl] propane, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 1,1-bis (4-aminophenyl) cyclohexane, α, α'- Bis (4-aminophenyl) -1,4-diisopropylbenzene, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis (4) -Aminophenyl) Hexafluoropropane, 4,4'-diaminodiphenylamine, 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrene , 1,6-diaminopyrene, 1,8-diaminopyrene, 2,7-diaminofluorene, 1,3-bis (4-amino) Phenyl) tetramethyldisiloxane, benzidine, 2,2'-dimethylbenzidine, 1,2-bis (4-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,4-bis (4) -Aminophenyl) butane, 1,5-bis (4-aminophenyl) pentane, 1,6-bis (4-aminophenyl) hexane, 1,7-bis (4-aminophenyl) heptane, 1,8-bis (4-Aminophenyl) octane, 1,9-bis (4-aminophenyl) nonane, 1,10-bis (4-aminophenyl) decane, 1,3-bis (4-aminophenoxy) propane, 1,4 -Bis (4-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,7-bis (4-aminophenoxy) heptane, 1 , 8-bis (4-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,10-bis (4-aminophenoxy) decane, di (4-aminophenyl) propane-1,3 -Geoate, di (4-aminophenyl) butane-1,4-dioate, di (4-aminophenyl) pentane-1,5-dioate, di (4-aminophenyl) hexane-1,6-dioate, di ( 4-Aminophenyl) heptane-1,7-dioate, di (4-aminophenyl) octane-1,8-dioate, di (4-aminophenyl) nonane-1,9-dioate, di (4-aminophenyl) Decane-1,10-dioate, 1,3-bis [4- (4-aminophenoxy) phenoxy] propane, 1,4-bis [4- (4-aminophenoxy) phenoxy] butane, 1,5-bis [ 4- (4-Aminophenoxy) phenoxy] pentane, 1,6-bis [4- (4-aminophenoxy) phenoxy] hexane, 1,7-bis [4- (4-aminophenoxy) phenoxy] heptane, 1, 8-bis [4- (4-aminophenoxy) phenoxy] octane, 1,9-bis [4- (4-aminophenoxy) phenoxy] nonane, 1,10-bis [4- (4-aminophenoxy) phenoxy] Decan etc. can be mentioned.

Examples of aromatic-aliphatic diamines include 3-aminobenzylamine, 4-aminobenzylamine, 3-amino-N-methylbenzylamine, 4-amino-N-methylbenzylamine, 3-aminophenethylamine, 4-. Aminophenethylamine, 3-amino-N-methylphenethylamine, 4-amino-N-methylphenethylamine, 3- (3-aminopropyl) aniline, 4- (3-aminopropyl) aniline, 3- (3-methylaminopropyl) Aniline, 4- (3-methylaminopropyl) aniline, 3- (4-aminobutyl) aniline, 4- (4-aminobutyl) aniline, 3- (4-methylaminobutyl) aniline, 4- (4-methyl) Aminobutyl) aniline, 3- (5-aminopentyl) aniline, 4- (5-aminopentyl) aniline, 3- (5-methylaminopentyl) aniline, 4- (5-methylaminopentyl) aniline, 2- ( Examples thereof include 6-aminonaphthyl) methylamine, 3- (6-aminonaphthyl) methylamine, 2- (6-aminonaphthyl) ethylamine, and 3- (6-aminonaphthyl) ethylamine.

Examples of heterocyclic diamines are 2,6-diaminopyridine, 2,4-diaminopyridine, 2,4-diamino-1,3,5-triazine, 2,7-diaminodibenzofuran, and 3,6-diaminocarbazole. , 2,4-Diamino-6-isopropyl-1,3,5-triazine, 2,5-bis (4-aminophenyl) -1,3,4-oxadiazole and the like.
Examples of aliphatic diamines include 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-Diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,3-diamino-2,2-dimethylpropane, 1,6-diamino-2,5-dimethylhexane, 1,7- Diamino-2,5-dimethylheptane, 1,7-diamino-4,4-dimethylheptane, 1,7-diamino-3-methylheptan, 1,9-diamino-5-methylheptane, 1,12-diaminododecane , 1,18-diaminooctadecane, 1,2-bis (3-aminopropoxy) ethane and the like.

（Ｒ_６は、炭素数１～２２を有する、アルキル基又はフッ素含有アルキル基である。）A diamine compound having an alkyl group, a fluorine-containing alkyl group, an aromatic ring, an aliphatic ring, a heterocycle, or a large cyclic substituent comprising them may be used in combination in the side chain. Specifically, the diamines represented by the following formulas [DA1] to [DA26] are exemplified.

(R ₆ is an alkyl group or a fluorine-containing alkyl group having 1 to 22 carbon atoms.)

（Ｓ_５は、－ＣＯＯ－、－ＯＣＯ－、－ＣＯＮＨ－、－ＮＨＣＯ－、－ＣＨ_２－、－Ｏ－、－ＣＯ－、又は－ＮＨ－を示し、Ｒ_６は炭素数１～２２を有する、アルキル基若しくはフッ素含有アルキル基を示す。）

(S ₅ indicates -COO-, -OCO-, -CONH-, -NHCO-, -CH _2- , -O-, -CO-, or -NH-, and R ₆ has 1 to 22 carbon atoms. Indicates an alkyl group or a fluorine-containing alkyl group having.)

（Ｓ_６は、－Ｏ－、－ＯＣＨ_２－、－ＣＨ_２Ｏ－、－ＣＯＯＣＨ_２－、又は－ＣＨ_２ＯＣＯ－を示し、Ｒ_７は炭素数１～２２を有する、アルキル基、アルコキシ基、フッ素含有アルキル基若しくはフッ素含有アルコキシ基である。）

(S ₆ indicates -O-, -OCH _2- , -CH ₂ O-, -COOCH _2- , or -CH ₂ OCO-, and R ₇ has an alkyl group or an alkoxy group having 1 to 22 carbon atoms. , Fluorine-containing alkyl group or fluorine-containing alkoxy group.)

（Ｓ_７は、－ＣＯＯ－、－ＯＣＯ－、－ＣＯＮＨ－、－ＮＨＣＯ－、－ＣＯＯＣＨ_２－、－ＣＨ_２ＯＣＯ－、－ＣＨ_２Ｏ－、－ＯＣＨ_２－、又は－ＣＨ_２－を示し、Ｒ_８は炭素数１～２２を有する、アルキル基、アルコキシ基、フッ素含有アルキル基若しくはフッ素含有アルコキシ基である。）

(S ₇ indicates -COO-, -OCO-, -CONH-, -NHCO-, -COOCH _2- , -CH ₂ OCO-, -CH ₂ O-, -OCH _2- , or -CH _2- . , R8 is an alkyl group, an alkoxy group, a fluorine-containing alkyl group or a fluorine-containing alkoxy group having ₁ to 22 carbon atoms.)

（Ｓ_８は、－ＣＯＯ－、－ＯＣＯ－、－ＣＯＮＨ－、－ＮＨＣＯ－、－ＣＯＯＣＨ_２－、－ＣＨ_２ＯＣＯ－、－ＣＨ_２Ｏ－、－ＯＣＨ_２－、－ＣＨ_２－、－Ｏ－、又は－ＮＨ－を示し、Ｒ_９はフッ素基、シアノ基、トリフルオロメタン基、ニトロ基、アゾ基、ホルミル基、アセチル基、アセトキシ基、又は水酸基である。）

( _S8 is -COO-, -OCO-, -CONH-, -NHCO-, -COOCH _2- , -CH ₂ OCO-, -CH ₂ O-, -OCH _2- , -CH _2- , -O -Or -NH-, and R ₉ is 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.)

（Ｒ₁₀は炭素数３～１２のアルキル基であり、１，４－シクロへキシレンのシス－トランス異性は、それぞれトランス体である。）

(R ₁₀ is an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomers of 1,4-cyclohexylene are trans isomers, respectively.)

In the case of alignment treatment with light, it is preferable to use the diamine of the general formula [1] in combination with the diamines of the above [DA-1] to [DA-26] because a more stable pretilt angle can be obtained. As a more preferable diamine that can be used in combination, the diamines of the formulas [DA-10] to [DA-26] are preferable, and the diamines of the formulas [DA-10] to [DA-16] are more preferable. The preferable content of these diamines is not particularly limited, but is preferably 5 to 50 mol% in the diamine component, and preferably 5 to 30 mol% in terms of printability.
In addition, the following diamines may be used in combination.

（ｍは０～３の整数であり、式［ＤＡ－３４］中、ｎは１～５の整数である）。
式[ＤＡ－２７]、式[ＤＡ－２８]等のジアミンを含有させることにより、液晶配向膜とした際の電圧保持特性を向上させることができ、式[ＤＡ－２９]～［ＤＡ－３４］のジアミンは蓄積電化の低減に効果がある。

(M is an integer of 0 to 3, and in the formula [DA-34], n is an integer of 1 to 5).
By containing diamines of the formulas [DA-27] and [DA-28], the voltage holding characteristics when the liquid crystal alignment film is formed can be improved, and the formulas [DA-29] to [DA-34] can be improved. ] Diamine is effective in reducing accumulated electrification.

（ｍは、１～１０の整数である。）
その他のジアミンは、液晶配向膜とした際の液晶配向性、電圧保持特性、蓄積電荷などの特性に応じて、１種、又は２種以上を混合して使用することもできる。Further, diaminosiloxane as represented by the following formula [DA-35] can also be mentioned as other diamines.

(M is an integer from 1 to 10.)
Other diamines may be used alone or in combination of two or more, depending on the characteristics such as liquid crystal orientation, voltage holding characteristics, and accumulated charge when the liquid crystal alignment film is formed.

<Manufacturing 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 can be used. Generally, it is a method of reacting a tetracarboxylic acid dianhydride component and a diamine component in an organic solvent. The reaction of the tetracarboxylic acid dianhydride component with the diamine is advantageous in that it proceeds relatively easily in an organic solvent and no by-products are generated.

The organic solvent used for the reaction between the tetracarboxylic acid dianhydride component and the diamine is not limited as long as it dissolves the produced polyamic acid. Specific examples are given below.
N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactum, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide , Gamma-butylollactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethylamyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cell solve, ethyl cell solve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl Carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol 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 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, Amyl Acetate, Butyl Butyrate, Butyl Ether , Diisobutylketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, acetic acid Ethyl, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropion Acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglime, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropanamide, 3- Examples thereof include ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide and the like. These may be used alone or in combination. Further, even if the solvent does not dissolve the polyamic acid, it may be mixed with the above solvent and used as long as the produced polyamic acid does not precipitate.

Further, since the water content in the organic solvent inhibits the polymerization reaction and further causes the produced polyamic acid to be hydrolyzed, it is preferable to use an organic solvent that has been 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 the organic solvent is stirred, and the tetracarboxylic acid dianhydride component is used as it is or is organic. A method of adding a tetracarboxylic acid dianhydride component dispersed or dissolved in a solvent, conversely 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 adding a tetracarboxylic acid dianhydride component and a diamine component. Examples thereof include a method of adding alternately, and any of these methods may be used. When the tetracarboxylic acid dianhydride component or the diamine component is composed of a plurality of types of compounds, the reaction may be carried out in a premixed state, may be reacted individually in sequence, or may be further reacted individually with a low molecular weight. The body may be mixed and reacted to form a high molecular weight compound.

The temperature at which the tetracarboxylic acid dianhydride component and the diamine component are reacted can be selected from −20 to 150 ° C., but is preferably in the range of −5 to 100 ° C. The reaction can be carried out at any concentration, but if the concentration is too low, it becomes difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution becomes too high, making uniform stirring difficult. Therefore, the total concentration of the tetracarboxylic acid dianhydride component and the diamine component in the reaction solution is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The initial reaction can be carried out at a high concentration and then an organic solvent can be added.
In the polyamic acid polymerization reaction, 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, and 0.9 to 1. 1 is more preferable. Similar to a normal polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the polyamic acid produced.

<Manufacturing of polyimide>
The polyimide of the present invention is a polyimide obtained by dehydrating and closing the polyamic acid, and is useful as a polymer for obtaining a liquid crystal alignment film.
In the polyimide of the present invention, the dehydration ring closure rate (imidization rate) of the amic acid group does not necessarily have to be 100%, and can be arbitrarily adjusted according to the intended use and purpose.
Examples of the method for imidizing a polyamic acid include a thermal imidization method in which a solution of the polyamic acid is heated as it is, and a catalytic imidization method in which a catalyst is added to the solution of the 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 remove the water generated by the imidization reaction from the system.

The catalytic imidization of the polyamic acid can be carried out by adding a basic catalyst and an acid anhydride to the solution of the polyamic acid and stirring at −20 to 250 ° C., preferably 0 to 180 ° C. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times, the amount of the amic acid group, and the amount of the acid anhydride is 1 to 50 mol times, preferably 3 to 3 times the amid acid group. It is 30 mol times. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like, and among them, pyridine is preferable because it has basicity suitable for advancing the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride and the like, and among them, acetic anhydride is preferable because it facilitates purification after the reaction is completed. The imidization rate by catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature, reaction time and the like.

The molecular weight of the polymer contained in the liquid crystal alignment agent of the present invention is determined by the GPC (Gel Permeation Chromatography) method in consideration of the strength of the obtained coating film, the workability at the time of forming the coating film, and the uniformity of the coating film. The measured weight average molecular weight is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000.

<Liquid crystal alignment agent>
The liquid crystal alignment 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 includes at least one polymer selected from the polymers of the present invention described above. The content of the resin component in the liquid crystal alignment agent is preferably 1 to 20% by mass, more preferably 3 to 15% by mass, and particularly preferably 3 to 10% by mass.
The resin component may be all the polymer of the present invention, or may be mixed with other polymers. At that time, the content of the other polymer in the resin component is 0.5 to 15% by mass, preferably 1 to 10% by mass.
Examples of such other polymers include polyamic acids or polyimides obtained by using a diamine compound other than the specific diamine compound as the diamine component to be reacted with the tetracarboxylic acid dianhydride component.

The organic solvent used for the liquid crystal alignment agent of the present invention is not particularly limited as long as it is an organic solvent that dissolves the resin component. Specific examples are given below.
N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactum, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethylsulfoxide, tetramethylurea, pyridine, Dimethylsulfone, hexamethylsulfoxide, γ-butyrolactone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide, 1,3 -Dimethyl-imidazolidinone, ethylamyl ketone, methylnonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglime, 4-hydroxy-4-methyl-2-pentanone and the like. .. These may be used alone or in combination.

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

For example, isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol mono. Isopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, propylene glycol monobutyl ether, dipropylene glycol 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 monopropyl ether, dipropylene glycol monoacetate monopropyl ether, dipropylene glycol dimethyl ether, 3 -Methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethylisobutyl ether, diisobutylene, amylacetate, butylbutyrate, butyl ether, diisobutylketone, methylcyclohexene, Propyl ether, dihexyl ether, 1-hexanol, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, Methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, 3 -Butyl methoxypropanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate , Propi Lenglycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl Examples thereof include solvents having a low surface tension such as esters, lactic acid n-propyl esters, lactic acid n-butyl esters, and lactic acid isoamyl esters.
These poor solvents may be used alone or in admixture of a plurality of types. When the above solvent is used, it is preferably 5 to 80% by mass, more preferably 20 to 60% by mass, based on the total amount of the solvent contained in the liquid crystal alignment agent.

Examples of the compound for improving the uniformity of the film thickness and the surface smoothness include a fluorine-based surfactant, a silicone-based surfactant, and a nonion-based surfactant.
More specifically, for example, Ftop EF301, EF303, EF352 (manufactured by Tochem Products), Megafuck F171, F173, R-30 (manufactured by Dainippon Ink Co., Ltd.), Florard FC430, FC431 (manufactured by Sumitomo 3M). , Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.) and the like. The ratio of these surfactants used is preferably 0.01 to 2 parts by mass, and more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the resin component contained in the liquid crystal alignment agent.

Specific examples of the compound that improves 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-aminopropyltrimethoxysilane. , N- (2-Aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 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-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxy Silane, N-bis (oxyethylene) -3-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-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N', N',-tetraglycidyl -4,4'-diaminodiphenylmethane and the like can be mentioned.

Further, in addition to improving the adhesion between the substrate and the film, it is preferable to contain the following phenoplast-based additives for the purpose of preventing deterioration of electrical characteristics due to the backlight. Specific phenoplast-based additives are shown below.

When a compound that improves adhesion to a substrate is used, the amount used is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the resin component. be. If the amount used is less than 0.1 parts by mass, the effect of improving the adhesion cannot be expected, and if it is more than 30 parts by mass, the orientation of the liquid crystal may be deteriorated.
In addition to the above, the liquid crystal alignment agent of the present invention includes a dielectric and a conductive substance for the purpose of changing the electrical characteristics such as the dielectric constant and conductivity of the liquid crystal alignment film as long as the effects of the present invention are not impaired. Further, a crosslinkable compound or the like for the purpose of increasing the hardness and the density of the liquid crystal alignment film may be added.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal alignment agent of the present invention can be applied on a substrate, fired, and then subjected to alignment treatment by rubbing treatment, light irradiation, or the like, or can be used as a liquid crystal alignment film without alignment treatment in vertical alignment applications. At this time, the substrate to be used is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, an acrylic substrate, a plastic substrate such as a polycarbonate substrate, or the like can be used. Further, it is preferable to use a substrate on which an ITO electrode or the like for driving a liquid crystal display is formed from the viewpoint of simplifying the process. Further, in the reflective liquid crystal display element, an opaque object such as a silicon wafer can be used if only one side of the substrate is used, and in this case, a material that reflects light such as aluminum can also be used as the electrode.
The method of applying the liquid crystal alignment agent is not particularly limited, but industrially, it is generally performed by a method such as screen printing, offset printing, flexographic printing, and inkjet printing. Other coating methods include dips, roll coaters, slit coaters, spinners, and the like, and these may be used depending on the intended purpose.

The firing after applying the liquid crystal alignment agent on the substrate can be performed at 50 to 300 ° C., preferably 80 to 250 ° C. by a heating means such as a hot plate, and the solvent can be evaporated to form a coating film. If the thickness of the coating film formed after firing is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may decrease. It is preferably 10 to 100 nm. When the liquid crystal is horizontally oriented or tilted, the fired coating film is treated by rubbing or irradiation with polarized ultraviolet rays.
The liquid crystal display element of the present invention is a liquid crystal display element obtained by obtaining a substrate with a liquid crystal alignment film from the liquid crystal alignment agent of the present invention by the above-mentioned method, and then producing a liquid crystal cell by a known method.

To give an example of manufacturing a liquid crystal cell, a pair of substrates on which a liquid crystal alignment film is formed is prepared, a spacer is sprayed on the liquid crystal alignment film of one of the substrates, and the liquid crystal alignment film surface is on the inside. Examples thereof include a method in which the other substrate is bonded and the liquid crystal is injected under reduced pressure to seal the liquid crystal, or a method in which the liquid crystal is dropped on the liquid crystal alignment film surface on which the spacer is sprayed and then the substrate is bonded and sealed. The thickness of the spacer is preferably 1 to 30 μm, more preferably 2 to 10 μm.

Examples of the present invention will be given below for more specific purposes, but the interpretation of the present invention is not limited to these examples. The abbreviations used in the examples and the method of character evaluation are as follows.

<Organic solvent>
NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve <additive>
LS-4668: 3-glycidoxypropyltriethoxysilane

<Viscosity measurement>
The viscosity of the solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL and a cone rotor TE-1 (1 ° 34', R24) at a temperature of 25 ° C. ..

<Manufacturing of liquid crystal display element>
First, a substrate with electrodes was prepared. The substrate is a rectangular glass substrate having a length of 30 mm and a width of 35 mm and a thickness of 0.7 mm. An IZO electrode having a solid pattern, which constitutes a counter electrode as a first layer, is formed on the substrate. A silicon nitride (SiN) film formed by a CVD method is formed as a second layer on the counter electrode of the first layer. The film thickness of the SiN film of the second layer is 500 nm, and it functions as an interlayer insulating film. A comb-shaped pixel electrode formed by patterning an IZO film as a third layer is arranged on the SiN film of the second layer to form two pixels, a first pixel and a second pixel. ing. The size of each pixel is 10 mm in length and about 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer has a comb-like shape formed by arranging a plurality of "dogleg" -shaped electrode elements having a bent central portion. The width of each electrode element in the lateral direction is 3 μm, and the distance between the electrode elements is 6 μm. Since the pixel electrodes forming each pixel are configured by arranging a plurality of bent dogleg-shaped electrode elements in the central portion, the shape of each pixel is not rectangular, but in the central portion like the electrode elements. It has a shape that resembles a bold "dogleg" that bends. Then, each pixel is divided into upper and lower parts with a bent portion in the center as a boundary, and has a first region on the upper side and a second region on the lower side of the bent portion.

Comparing the first region and the second region of each pixel, the forming directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode elements of the pixel electrodes are formed so as to form an angle (clockwise) of + 10 ° in the first region of the pixel, and the pixel is formed in the second region of the pixel. The electrode elements of the electrodes are formed so as to form an angle of −10 ° (clockwise). As a result, in the first region and the second region of each pixel, the direction of the rotation operation (inplane switching) of the liquid crystal in the substrate surface induced by the voltage application between the pixel electrode and the counter electrode is changed. It is configured to be in opposite directions to each other.

Next, after filtering the liquid crystal alignment agent with a 1.0 μm filter, an ITO film is formed on the back surface of the prepared substrate with electrodes and the opposite substrate, and the glass has a columnar spacer having a height of 4 μm. Each of the substrates was spin coated. Then, after drying on a hot plate at 80 ° C. for 2 minutes and firing at 230 ° C. for 20 minutes, a polyimide film having a film thickness of 60 nm was obtained on each substrate. After rubbing (roll diameter 120 mm, rotation speed 500 rpm, moving speed 30 mm / sec, pushing amount 0.3 mm) on this polyimide film with a rayon cloth in a predetermined rubbing direction, ultrasonic irradiation is performed in pure water for 1 minute. And dried at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.

Using the two types of substrates with the obtained liquid crystal alignment film, combine them so that their rubbing directions are antiparallel, seal the surroundings leaving the liquid crystal injection port, and create an empty cell with a cell gap of 3.5 μm. Made. A liquid crystal (MLC-3019, manufactured by Merck & Co., Inc.) was vacuum-injected into this empty cell at room temperature, and then the injection port was sealed to obtain an anti-parallel oriented liquid crystal cell. The obtained liquid crystal cell constitutes an FFS mode liquid crystal display element. Then, the obtained liquid crystal cell was heated at 120 ° C. for 1 hour, left overnight, and then used for each evaluation.

<Evaluation of liquid crystal orientation>
Using the liquid crystal cell produced above, an AC voltage of 10 VPP was applied for 168 hours at a frequency of 30 Hz in a constant temperature environment of 60 ° C. Next, 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 it to stand, the liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the backlight is turned on with no voltage applied so that the brightness of the transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the first pixel became the darkest to the angle at which the first region became the darkest was calculated as the angle Δ. Similarly, in the second pixel, the second region and the first region were compared, and the same angle Δ was calculated. Then, the average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal cell. The smaller the angle Δ of the liquid crystal cell, the higher the liquid crystal orientation.

<Measurement of pre-tilt angle>
The pretilt angle of the liquid crystal cell produced above was measured. Further, the liquid crystal cell was heated at 110 ° C. for 1 hour in a heat circulation oven, and then the pretilt angle was measured. The pre-tilt angle was measured using a minute tilt angle measuring device (OPTI-PRO manufactured by Shintech).

<Preparation of adhesiveness evaluation sample>
The liquid crystal alignment agent is filtered through a filter having a pore size of 1.0 μm, spin-coated on a glass substrate with a transparent electrode, dried on a hot plate at 80 ° C. for 2 minutes, and then fired at 230 ° C. for 20 minutes to a film thickness of 70 nm. A coating film was obtained. Two substrates thus obtained were prepared, and a bead spacer with a diameter of 4 μm (manufactured by JGC Catalysts and Chemicals Co., Ltd., Shinkokyu, SW-D1) was sprayed on the liquid crystal alignment film surface of one of the substrates, and then UV (UV) ( Ultraviolet rays) Curable adhesive was dropped. Next, the liquid crystal alignment film surface of the other substrate was placed inside, and the substrates were bonded so that the overlapping width was 0.5 cm. At that time, the amount of the sealant dropped was adjusted so that the diameter of the sealant after bonding was about 3 mm. After fixing the two bonded substrates with a clip, irradiate with 3.0J of UV with a wavelength of 365 nm using a cut filter with a wavelength of 325 nm or less, and then heat-curing at 120 ° C. for 1 hour for adhesion evaluation. Samples were prepared.

<Measurement of adhesive strength>
After fixing the end portions of the upper and lower substrates of the prepared sample with a desktop precision universal testing machine, the sample was pulled up and down from both ends of the short sides of the substrate, and the pressure (N) at the time of peeling was measured. Then, the adhesive strength was evaluated using the value obtained by normalizing the pressure (N) with the area (mm ² ) estimated from the measured diameter of the sealant. A 3 mm diameter seal fracture surface was observed. When the contact area of the seal cross section was more than half, it was judged to be good, and when the contact area of the seal was less than half, it was judged to be defective.

(Synthesis Example 1)
A 50 mL four-necked flask equipped with a stirrer is used as a nitrogen atmosphere, and DA-1 is 1.56 g (5.28 mmol), DA-4 is 1.91 g (7.82 mmol), and DA-6 is 0.724 g (0.724 mmol). Weighed 1.30 mmol), added 46.5 g of NMP, and stirred while feeding nitrogen to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 485.1 mPa). -S, PAA-1) was obtained.

(Synthesis Example 2)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, and DA-1 was 0.773 g (2.58 mmol), DA-4 was 2.22 g (9.09 mmol), and DA-6 was 0.724 g (0.724 mmol). Weighed 1.30 mmol), added 46.5 g of NMP, and stirred while feeding nitrogen to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 505.4 mPa. s, PAA-2) was obtained.

(Synthesis Example 3)
A 50 mL four-necked flask equipped with a stirrer is used as a nitrogen atmosphere, and DA-1 is 0.723 g (2.41 mmol), DA-4 is 2.06 g (8.40 mmol), and DA-6 is 0.724 g (0.724 mmol). Weighed 1.30 mmol), added 46.9 g of NMP, and stirred while feeding nitrogen to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 456.1 mPa. s, PAA-3) was obtained.

(Synthesis Example 4)
A 50 mL four-necked flask equipped with a stirrer is used as a nitrogen atmosphere, and DA-1 is 1.16 g (3.87 mmol), DA-4 is 1.91 g (7.82 mmol), and DA-6 is 0.723 g (0.723 mmol). Weighed 1.30 mmol), added 47.7 g of NMP, and stirred while feeding nitrogen to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 513.9 mPa. s, PAA-4) was obtained.

(Synthesis Example 5)
A 50 mL four-necked flask equipped with a stirrer is used as a nitrogen atmosphere, and DA-1 is 0.778 g (2.60 mmol), DA-4 is 2.06 g (8.43 mmol), and DA-6 is 1.09 g (. Weighed 1.96 mmol), added 48.7 g of NMP, and stirred while feeding nitrogen to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 80.9 mPa. s, PAA-5) was obtained.

(Synthesis Example 6)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, and DA-1 was 0.973 g (3.25 mmol), DA-4 was 1.91 g (7.82 mmol), and DA-6 was 1.09 g (1). .96 mmol) Weighed, 48.7 g of NMP was added, and the mixture was dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 471.4 mPa. s, PAA-6) was obtained.

(Synthesis Example 7)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, and DA-1 was 1.16 g (3.86 mmol), DA-4 was 1.74 g (7.12 mmol), and DA-6 was 1.09 g (1). .96 mmol) Weighed, 49.2 g of NMP was added, and the mixture was dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 462.8 mPa. s, PAA-7) was obtained.

(Synthesis Example 8)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, and DA-1 was 0.780 g (2.61 mmol), DA-4 was 1.91 g (7.82 mmol), and DA-6 was 1.45 g (2). .60 mmol) Weighed, 50.2 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 475.2 mPa. s, PAA-8) was obtained.

(Synthesis Example 9)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, and DA-1 was 0.973 g (3.23 mmol), DA-4 was 1.74 g (7.12 mmol), and DA-6 was 1.45 g (1.23 mmol). Weighed 2.61 mmol), added 50.4 g of NMP, and stirred while feeding nitrogen to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 451.6 mPa. s, PAA-9) was obtained.

(Synthesis Example 10)
A 50 mL four-necked flask equipped with a stirrer is used as a nitrogen atmosphere, and DA-1 is 1.16 g (3.88 mmol), DA-4 is 1.58 g (6.47 mmol), and DA-6 is 1.44 g (. 2.60 mmol) Weighed, 50.7 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 41.4 mPa. s, PAA-10) was obtained.

(Synthesis Example 11)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, and DA-1 was 0.778 g (2.59 mmol), DA-4 was 2.60 g (9.08 mmol), and DA-6 was 0.724 g (0.724 mmol). 1.3 mmol) Weighed, 50.0 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 498.1 mPa. s, PAA-11) was obtained.

(Synthesis Example 12)
Using a 500 mL four-necked flask equipped with a stirrer as a nitrogen atmosphere, weigh 22.3 g (0.112 mol) of DA-2 and 5.55 g (0.026 mol) of DA-3, add 442 g of NMP, and add nitrogen. Was stirred and dissolved while feeding. While stirring this diamine solution, 26.3 g (0.105 mol) of CA-3 was added, and after stirring at 50 ° C. for 2 hours, 6.18 g (0.032 mol) of acid dianhydride (CA-2) was added. Then, the mixture was stirred for 2 hours while cooling with cold water to obtain a polyamic acid solution (viscosity: 1442 mPa · s, PAA-12).

(Synthesis Example 13)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, 3.17 g (13.0 mmol) of DA-4 was weighed, 43.0 g of NMP was added, and the mixture was stirred and dissolved while sending nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 550.1 mPa. s, PAA-13) was obtained.

(Synthesis Example 14)
Using a 50 mL four-necked flask equipped with a stirrer as a nitrogen atmosphere, weigh 2.86 g (11.7 mmol) of DA-4 and 0.724 g (1.3 mmol) of DA-6, and add 46.1 g of NMP. , Nitrogen was sent and stirred to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 523.2 mPa. s, PAA-14) was obtained.

(Synthesis Example 15)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, weighed 2.54 g (10.4 mmol) of DA-4 and 1.45 g (2.60 mmol) of DA-6, and added 49.1 g of NMP. , Nitrogen was sent and stirred to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 502.7 mPa. s, PAA-15) was obtained.

(Synthesis Example 16)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, weighed 0.518 g (2.60 mmol) of DA-2 and 2.51 g (10.3 mmol) of DA-4, and added 42.3 g of NMP. , Nitrogen was sent and stirred to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 531.5 mPa. s, PAA-16) was obtained.

(Synthesis Example 17)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, weighed 1.04 g (5.22 mmol) of DA-2 and 1.91 g (7.82 mmol) of DA-4, and added 41.4 g of NMP. , Nitrogen was sent and stirred to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 542.2 mPa. s, PAA-17) was obtained.

(Synthesis Example 18)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, 3.72 g (13.0 mmol) of DA-5 was weighed, 47.2 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 525.2 mPa. s, PAA-18) was obtained.

(Synthesis Example 19)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, weighed 0.51 g (2.61 mmol) of DA-2 and 2.97 g (10.4 mmol) of DA-5, and added 47.2 g of NMP. , Nitrogen was sent and stirred to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 547.1 mPa. s, PAA-19) was obtained.

(Synthesis Example 20)
A 50 mL (liter) four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, and 0.773 g (2.50 mmol) of DA-1 and 2.54 g (10.4 mmol) of DA-4 were weighed to obtain NMP. 46.5 g was added, and the mixture was dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 510.7 mPa. s, PAA-20) was obtained.

(Synthesis Example 21)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, weighed 0.773 g (2.58 mmol) of DA-1 and 2.98 g (10.4 mmol) of DA-5, and added 47.4 g of NMP. , Nitrogen was sent and stirred to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 525.3 mPa. s, PAA-21) was obtained.

(Synthesis Example 22)
A 50 mL four-necked flask equipped with a stirrer was used as a nitrogen atmosphere, weighed 1.56 g (5.21 mmol) of DA-1, 2.23 g (7.79 mmol) of DA-4, and 47.7 g of NMP. In addition, nitrogen was sent and stirred to dissolve. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, and the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 510.4 mPa. s, PAA-22) was obtained.

(Examples 1 to 11)
4.36 g of each of the polyamic acid solutions (PAA-1) to (PAA-12) obtained in Synthesis Examples 1 to 11 was taken. 11.3 g of the polyamic acid solution (PAA-12) obtained in Synthesis Example 12 was added thereto, and NMP solution containing 13.9 g of NMP, 8.00 g of BCS and 1% by weight of LS-4668 while stirring. Was added in an amount of 2.4 g, and the mixture was further stirred at room temperature for 2 hours to obtain liquid crystal alignment agents (AL-1) to (AL-11), respectively.

(Comparative Examples 1 to 10)
4.36 g of each of the polyamic acid solutions (PAA-13) to (PAA-22) obtained in Comparative Synthesis Examples 1 to 7 was taken. 11.3 g of the polyamic acid solution (PAA-12) obtained in Synthesis Example 12 was added thereto, and NMP solution containing 13.9 g of NMP, 8.00 g of BCS and 1% by weight of LS-4668 while stirring. Was added in an amount of 2.4 g, and the mixture was further stirred at room temperature for 2 hours to obtain liquid crystal alignment agents (AL-12) to (AL-21), respectively.

<Evaluation>
For each of the liquid crystal alignment agents (AL-1) to (AL-21) of Examples 1 to 11 and Comparative Examples 1 to 10 obtained above, the liquid crystal orientation, the evaluation of the pretilt angle, and the evaluation of the seal adhesion are evaluated. Was done. The results are shown in Table 1.

The liquid crystal alignment agent of the present invention is used in a wide range of fields such as narrow frame type, high-sealability mobile liquid crystal display elements such as smartphones and mobile phones, and large liquid crystal display elements that require high definition and low cost. Will be done.
The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2016-168471 filed on August 30, 2016 are cited here as the disclosure of the specification of the present invention. , Incorporate.

Claims (7)

A diamine component containing a specific diamine 1 represented by any of the following formulas, a specific diamine 2 represented by any of the following formulas, and a specific diamine 3 represented by any of the following formulas, and a tetra. A liquid crystal alignment agent comprising at least one polymer selected from the group consisting of a polyamic acid obtained by reaction with a carboxylic acid dianhydride component and a polyimide obtained by imidizing the polyamic acid.
<Specific diamine 1>
However, Boc in the following formula represents a tert-butoxycarbonyl group.

<Specific diamine 2>

<Specific diamine 3>
However, Boc in the following formula represents a tert-butoxycarbonyl group.

The liquid crystal alignment agent according to claim 1, wherein the content of the specific diamine 1 in the diamine component is 5 to 95 mol%. Claim 1 in which the total content ratio of the specific diamine 2 and the specific diamine 3 is 10 to 60 mol%, and the content ratio (molar ratio) of the specific diamine 2 : the specific diamine 3 is 10:90 to 90:10. Or the liquid crystal alignment agent according to 2 . The liquid crystal alignment agent according to any one of claims 1 to 3 , wherein the tetracarboxylic acid dianhydride is a compound represented by the following formula [7].

(In the formula, Z ₁ is a tetravalent organic group having 4 to 13 carbon atoms and has an aromatic cyclic hydrocarbon group.) The liquid crystal alignment agent according to claim 4 , wherein Z ₁ has any of the structures represented by the following formulas [7a] to [7k].

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