WO2018043326A1

WO2018043326A1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: WO2018043326A1
Application number: PCT/JP2017/030520
Authority: WO
Inventors: 尚士鉄谷; 武重林; 静如呉; 啓文志田
Original assignee: 日産化学工業株式会社
Priority date: 2016-08-30
Filing date: 2017-08-25
Publication date: 2018-03-08
Also published as: TW201825595A; CN109891310A; KR20190045258A; KR102469386B1; CN109891310B; TWI735642B; JPWO2018043326A1; JP7081488B2

Abstract

Provided is a liquid crystal alignment agent that enables improving seal adhesiveness in a liquid crystal element to be sealed with a sealing agent, and also enables a resultant liquid crystal alignment film to not become in blackish-brown in color while retaining transparency and to have fine properties such as a pre-tilt angle and liquid crystal alignment. This liquid crystal alignment agent comprises at least one polymer selected from the group consisting of: polyamic acids obtained from a reaction between a tetracarboxylic acid dianhydride component, and a diamine component that contains a diamine having the structure of formula [1], a diamine having the structure of formula [2], and a diamine having the structure of formula [3]; and polyimides obtained by imidizing said polyamic acids. (The definitions of the respective symbols in the formulas are as described in the description.)

Description

Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

The present invention relates to a liquid crystal aligning 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 aligning liquid crystals in a certain direction. Currently, the main liquid crystal alignment film used industrially is formed from a liquid crystal aligning agent made of a polyimide precursor polyamic acid (also referred to as polyamic acid) or a polyimide solution. Specifically, a liquid crystal aligning agent is applied to a substrate, heated and fired, and then subjected to a liquid crystal aligning treatment.

Conventionally, surface treatment by rubbing is mainly performed as the liquid crystal alignment treatment. However, in the rubbing treatment, it is usually difficult to perform highly uniform alignment treatment, and liquid crystal alignment defects and defects in the liquid crystal alignment film are caused. Occasionally, display defects may occur, and there may be problems such as dust generation. In recent years, there has been a tendency to increase the area of the substrate and increase the unevenness due to the increase in size, definition, and cost of the substrate used for the panel. When forming an alignment film on such a substrate, rubbing is performed. Processing still leaves room for improvement.

On the other hand, an alignment process using a photoreaction has been proposed as an alignment process method instead of the rubbing method. Specifically, a method of imparting liquid crystal alignment ability by forming a polymer film having a specific site causing a photoreaction such as polyvinyl cinnamate on the substrate surface and irradiating with polarized or non-polarized radiation ( The photo-alignment method) is known. According to this method, uniform liquid crystal alignment can be realized without generating static electricity or dust, and viewing angle can be improved by alignment division (see Patent Documents 1 and 2).

Further, in liquid crystal cells such as TN (Twisted Nematic) and STN (Super Twisted Nematic), the liquid crystal alignment film needs to have a function of tilting and aligning liquid crystal molecules at a predetermined angle (pretilt angle) with respect to the substrate surface. . In order to develop a pretilt angle, a liquid crystal alignment film using a polyamic acid having an alkyl side chain, a side chain of a steroid skeleton, a side chain having a ring structure, polyimide, or the like is known (Patent Documents 3 and 4). 5). In the alignment treatment 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 normal direction of the substrate (see Patent Document 1).

Japanese Unexamined Patent Publication No. 6-287453 Japanese Unexamined Patent Publication No. 9-297313 Japanese Unexamined Patent Publication No. 05-043687 Japanese Unexamined Patent Publication No. 04-281427 Japanese Unexamined Patent Publication 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 that is as large as possible, a so-called narrow frame is required in which the width of a sealing agent used for bonding between substrates of a liquid crystal display element is as narrow as possible. As the panel becomes narrower, a sealant used for manufacturing a liquid crystal display element is applied at a position close to the end of the liquid crystal alignment film or 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 adhesion between the substrates is insufficient. . In such a case, particularly when used under high temperature and high humidity conditions, water tends to be mixed from between the sealing agent and the liquid crystal alignment film, resulting in a problem that display unevenness occurs near the frame of the liquid crystal display element. . For this reason, it is necessary to improve the adhesiveness (adhesion) between the liquid crystal alignment film and the sealing agent or the substrate. On the other hand, the improvement of the adhesive property of the liquid crystal alignment film with the sealing agent or the substrate needs to be achieved without deteriorating the liquid crystal alignment property and electrical characteristics of the liquid crystal alignment film.
The main object of the present invention is to provide a liquid crystal aligning agent that can improve the adhesion between the liquid crystal aligning film and the sealing agent or the substrate without deteriorating the liquid crystal aligning property and electrical characteristics.

As a result of intensive studies to achieve the above object, the present inventors have completed the present invention.
The present invention relates to 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 dianhydride component. The gist of the present invention 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 heat-eliminable group that is replaced with 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 when m is 3 to 18, —O— may exist between any carbon-carbon bonds. n is an integer of 2 to 18. When n is 3 to 18, —O— may exist between any carbon-carbon bonds. * Represents a bond.

The liquid crystal aligning agent of the present invention can improve the seal adhesion in a liquid crystal display element sealed with a sealing agent, and the obtained liquid crystal aligning film is not colored black brown and does not lose transparency. And characteristics such as pretilde angle are good.

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

<Specific diamine 1>
The specific diamine 1 contained in the liquid crystal aligning agent of the present invention is a diamine having a structure represented by the following formula [1].

In the formula [1], A is a heat-eliminable group that can be replaced with hydrogen by heating at a temperature of 150 to 300 ° C. The thermally desorbable group is more preferably removed at 170 to 300 ° C, particularly preferably at 180 to 250 ° C. * Represents a bond.

Examples of the thermal leaving group include carbamate organic compounds represented by benzyloxycarbonyl group, 9-fluorenylmethyloxycarbonyl group, allyloxycarbonyl group, tertiary butoxycarbonyl group (also referred to as Boc group), and the like. Groups. A Boc group or a 9-fluorenylmethoxycarbonyl group is particularly preferred from the viewpoint that the elimination efficiency is high and the gas is harmless at the time of elimination at a relatively low temperature.

The amino group possessed by 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 amino group is substituted with an alkyl group having a relatively small molecular weight such as a methyl group, an ethyl group, a propyl group, or a butyl group.
The hydrogen atom of the benzene ring in the formula [1] is optionally substituted with an alkyl group or 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. May be.
Preferable specific examples of the diamine represented by the formula [1] include the following diamines. In the formula, Boc represents a tert-butoxycarbonyl group.

<Specific diamine 2>
The specific diamine 2 contained in the liquid crystal aligning 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, and preferably an integer of 2 to 18. When m is an integer of 3 to 18, —O— may exist between any carbon-carbon bonds. * Represents a bond with another atom.
The hydrogen atom of the benzene ring in the formula [2] is optionally substituted with an alkyl or alkoxy group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, or a halogen group such as a chlorine atom, bromine atom or fluorine atom. May be.
Preferable specific examples of the diamine having the structure represented by the formula [2] include, but are not limited to, the following diamines.

<Specific diamine 3>
The specific diamine 3 contained in the liquid crystal aligning 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 when n is an integer of 3 to 18, —O— may exist between any carbon-carbon bonds. The definition of A and its preferred range are the same as A in formula [1]. * Represents a bond.
The hydrogen atom of the benzene ring in the formula [3] is optionally substituted with an alkyl group or alkoxy group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, or a halogen group such as a chlorine atom, bromine atom or fluorine atom. May be.
Preferable specific examples of the diamine represented by the formula [3] include, but are not limited to, the following diamines.

<Tetracarboxylic dianhydride component>
In order to obtain the polyimide precursor of the present invention, a tetracarboxylic dianhydride (also referred to as a specific tetracarboxylic dianhydride) represented by the following formula [7] is used as a part of the tetracarboxylic 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], a preferred group of Z ₁ is a group represented by the formula [7a] or the formula [7g] from the viewpoint of polymerization reactivity and ease of synthesis. Of these, the formula [7a] is most preferable.
When the tetracarboxylic dianhydride having the structure of the formula [7a] is used, it is preferably 20% by mass or more of the total tetracarboxylic dianhydride component, more preferably 30% by mass or more. is there. A desired effect can be obtained by using it for the production of a polyimide precursor. More preferably, it is 30 mass% or more. All of the tetracarboxylic acid components used for the polyimide synthesis may be tetracarboxylic dianhydrides having the structure of the formula [7a].

In the present invention, an aliphatic tetracarboxylic dianhydride other than the specific tetracarboxylic dianhydride and other tetracarboxylic acid components can be used.
Examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride. Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4- Cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride 1,3-diphenyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexane Tetracarboxylic dianhydride, 1,2,3,4-cycloheptanetetracarboxylic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 3,4-dicarboxy-1-cycl Hexylsuccinic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, bicyclo [3 , 3,0] octane-2,4,6,8-tetracarboxylic dianhydride, bicyclo [4,3,0] nonane-2,4,7,9-tetracarboxylic 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 dianhydride, 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3 , 4-Tetrahydraphthalene-1,2-dicarboxylic acid Anhydride, bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3 -Cyclohexane-1,2-dicarboxylic dianhydride, tetracyclo [6,2,1,1,0,2,7] dodeca-4,5,9,10-tetracarboxylic dianhydride, 3, And 5,6-tricarboxynorbornane-2: 3,5: 6 dicarboxylic dianhydride.
Other tetracarboxylic acid components include tetracarboxylic acid, tetracarboxylic acid dihalide, tetracarboxylic dianhydride, esterified product obtained by dialkyl esterifying the carboxylic acid group of tetracarboxylic acid, and dialkyl carboxylic acid group of tetracarboxylic acid dihalide. Examples include esterified esterified products.

The above-mentioned other tetracarboxylic acid components can be used alone or in combination of two or more kinds in consideration of characteristics such as liquid crystal alignment properties, voltage holding characteristics and accumulated charges of the liquid crystal alignment film to be formed.

<Polymer>
The liquid crystal aligning agent contains a polyamic acid and / or a polyimide obtained by imidizing the polyamic acid (hereinafter also collectively referred to as a polymer).
Among these, the polymer of the present invention is a polyamic acid obtained by reaction of a diamine component containing the specific diamines 1, 2 and 3 and a tetracarboxylic dianhydride component, and / or imidizing the polyamic acid. It means the polyimide obtained. On the other hand, the polymer other than the present invention is a polyamic acid obtained by reaction of a diamine component containing a diamine which is not thermally desorbed and protected and a tetracarboxylic dianhydride component, and / or the polyamic acid. Means polyimide obtained by imidization.

<Polyamic acid>
A polyamic acid is obtained by reaction of a diamine component containing a diamine and a tetracarboxylic dianhydride component.
The content ratio of the specific diamine 1, 2 and 3 in the diamine component for obtaining the polyamic acid as the polymer of the present invention by reaction with the tetracarboxylic dianhydride component is preferably 5 to 95 mol% of the specific diamine 1. More preferably, it is 10 to 60 mol%.
The total content 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 to the specific diamine 3 is preferably 10:90 to 90:10, and 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 liquid crystal and a property of improving the vertical alignment property of liquid crystal. Therefore, other diamines can be used in combination. 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 other diamines include alicyclic diamines, aromatic-aliphatic diamines, heterocyclic diamines, and aliphatic diamines (excluding diamines represented by the formulas [1] to [3]). It is done.

Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4′-diaminodicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexylamine, isophorone diamine Etc.
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′-diaminostilbene, 4,4′-diaminostilbene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 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-aminophenyl) Enoxy) 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-aminophenyl) tetramethyldisi Xanthone, 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-dioate, 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-aminopheno) 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- And bis [4- (4-aminophenoxy) phenoxy] decane.

Examples of aromatic-aliphatic diamines include 3-aminobenzylamine, 4-aminobenzylamine, 3-amino-N-methylbenzylamine, 4-amino-N-methylbenzylamine, 3-aminophenethylamine, 4-aminobenzylamine, 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- (6-aminonaphthyl) methylamine, 3- (6-aminonaphthyl) methylamine, 2- (6 -Aminonaphthyl) ethylamine, 3- (6-aminonaphthyl) ethylamine and the like.

Examples of heterocyclic diamines include 2,6-diaminopyridine, 2,4-diaminopyridine, 2,4-diamino-1,3,5-triazine, 2,7-diaminodibenzofuran, 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-methylheptane, 1,9-diamino-5-methylheptane, 1,12-diaminododecane 1,18-diaminooctadecane, 1,2-bis (3-aminopropoxy) ethane and the like.

You may use together the diamine compound which has an alkyl group, a fluorine-containing alkyl group, an aromatic ring, an aliphatic ring, a heterocyclic ring, or the macrocyclic substituent which consists of them in a side chain. Specifically, 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 represents —COO—, —OCO—, —CONH—, —NHCO—, —CH ₂ —, —O—, —CO—, or —NH—, and R ₆ represents 1 to 22 carbon atoms. It has an alkyl group or a fluorine-containing alkyl group.)

(S ₆ represents —O—, —OCH ₂ —, —CH ₂ O—, —COOCH ₂ —, or —CH ₂ OCO—, and R ₇ represents an alkyl group or alkoxy group having 1 to 22 carbon atoms. , A fluorine-containing alkyl group or a fluorine-containing alkoxy group.)

(S ₇ represents —COO—, —OCO—, —CONH—, —NHCO—, —COOCH ₂ —, —CH ₂ OCO—, —CH ₂ O—, —OCH ₂ —, or —CH ₂ —. R ₈ represents 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 is —COO—, —OCO—, —CONH—, —NHCO—, —COOCH ₂ —, —CH ₂ OCO—, —CH ₂ O—, —OCH ₂ —, —CH ₂ —, —O — Represents — or —NH—, and R ₉ represents a fluorine group, a cyano group, a trifluoromethane group, a nitro group, an azo group, a formyl group, an acetyl group, an acetoxy group, or a hydroxyl group.

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

In the case of aligning with light, it is preferable to use a 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. More preferred diamines that can be used in combination are those represented by the formulas [DA-10] to [DA-26], more preferably diamines of [DA-10] to [DA-16]. The preferred content of these diamines is not particularly limited, but is preferably 5 to 50 mol% in the diamine component, and is preferably 5 to 30 mol% in terms of printability.
Moreover, you may use the following diamine together.

(M is an integer of 0 to 3, and n is an integer of 1 to 5 in the formula [DA-34]).
By containing a diamine of formula [DA-27], formula [DA-28] or the like, the voltage holding characteristics when a liquid crystal alignment film is formed can be improved. Formulas [DA-29] to [DA-34 ] Is effective in reducing the accumulation of electricity.

Furthermore, diaminosiloxanes represented by the following formula [DA-35] can also be mentioned as other diamines.

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

<Production of polyamic acid>
As a method for obtaining the polyamic acid of the present invention by the reaction of the tetracarboxylic dianhydride component and the diamine component, a known method can be used. In general, the tetracarboxylic dianhydride component and the diamine component are reacted in an organic solvent. The reaction between the tetracarboxylic dianhydride component and 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 dianhydride component and the diamine is not limited as long as the produced polyamic acid dissolves. Specific examples are given below.
N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide , Γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl Carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethyl 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, diisobutyl ketone, 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, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, Ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropion , 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy -N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide and the like. These may be used alone or in combination. Furthermore, even if it is a solvent which does not dissolve a polyamic acid, you may mix and use it for the said solvent in the range which the produced | generated polyamic acid does not precipitate.

Further, since water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the generated polyamic acid, it is preferable to use a dehydrated and dried organic solvent as much as possible.
When the tetracarboxylic 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 dianhydride component is used as it is or in an organic solvent. A method of adding by dispersing or dissolving in a solvent, a method of adding a diamine component to a solution in which a tetracarboxylic dianhydride component is dispersed or dissolved in an organic solvent, and a tetracarboxylic dianhydride component and a diamine component. The method of adding alternately etc. is mentioned, You may use any of these methods. In addition, when the tetracarboxylic dianhydride component or the diamine component is composed of a plurality of types of compounds, they may be reacted in a premixed state, may be individually reacted sequentially, or may be further reacted individually. The body may be mixed and reacted to form a high molecular weight body.

The temperature at which the tetracarboxylic dianhydride component reacts with the diamine component 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 is difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring is difficult. Therefore, the total concentration of the tetracarboxylic 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 stage of the reaction is carried out at a high concentration, and then an organic solvent can be added.
In the polymerization reaction of polyamic acid, the ratio of the total number of moles of the tetracarboxylic dianhydride component to the total number of moles of the diamine component is preferably 0.8 to 1.2, preferably 0.9 to 1. 1 is more preferable. Similar to the normal polycondensation reaction, the molecular weight of the polyamic acid produced increases as the molar ratio approaches 1.0.

<Manufacture of polyimide>
The polyimide of the present invention is a polyimide obtained by dehydrating and ring-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 cyclization rate (imidation rate) of the amic acid group is not necessarily 100%, and can be arbitrarily adjusted according to the application and purpose.
Examples of the method for imidizing a polyamic acid include a thermal imidization method in which a polyamic acid solution is heated as it is, and a catalyst imidation method in which a catalyst is added to the polyamic acid solution.
The temperature at which the polyamic acid is thermally imidized in the solution is 100 to 400 ° C., preferably 120 to 250 ° C., and is preferably carried out while removing water generated by the imidization reaction from the system.

The catalytic imidation of polyamic acid can be carried out by adding a basic catalyst and an acid anhydride to a polyamic acid solution 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 amidic acid group, and the amount of the acid anhydride is 1 to 50 mol times, preferably 3 to 30 mol times the amido group. 30 mole times. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Among them, pyridine is preferable because it has basicity suitable for proceeding with the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Among them, use of acetic anhydride is preferable because purification after completion of the reaction is facilitated. The imidization rate by catalytic imidation 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 aligning agent of the present invention is determined by GPC (Gel Permeation Chromatography) method in consideration of the strength of the obtained coating film, workability at the time of coating film formation, and uniformity of the coating film. The measured weight average molecular weight is preferably 5,000 to 1,000,000, and more preferably 10,000 to 150,000.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of this invention is a coating liquid for forming a liquid crystal aligning film, and is a solution which the resin component for forming a resin film melt | dissolved in the organic solvent. Here, the said resin component contains at least 1 type of polymer chosen from the polymer of above-described this invention. The content of the resin component in the liquid crystal aligning agent is preferably 1 to 20% by mass, more preferably 3 to 15% by mass, and particularly preferably 3 to 10% by mass.
All of the resin components may be the polymer of the present invention, or other polymers may be mixed. In that case, 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 polymer include polyamic acid or polyimide obtained by using a diamine compound other than the specific diamine compound as a diamine component to be reacted with the tetracarboxylic dianhydride component.

The organic solvent used for the liquid crystal aligning agent of this invention will not be specifically limited if it is an organic solvent in which a resin component is dissolved. Specific examples are given below.
N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 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, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, 4-hydroxy-4 Such as methyl-2-pentanone and the like. These may be used alone or in combination.

The liquid crystal aligning agent of this 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 a solvent-rich substance that improves film thickness uniformity and surface smoothness when a liquid crystal aligning agent is applied.
The following are mentioned as a specific example of the solvent (poor solvent) which improves the uniformity of film thickness and surface smoothness.

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 monoacetate 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, die Lenglycol 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, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl Ketone, 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-methoxypropionate Acid butyl, 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, ethyl lactate Examples thereof include solvents having low surface tension such as esters, lactic acid n-propyl ester, lactic acid n-butyl ester, and lactyl isoamyl ester.
These poor solvents may be used alone or in combination. 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 solvent contained in the liquid crystal aligning agent.

Examples of compounds that improve film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants.
More specifically, for example, F-top EF301, EF303, EF352 (manufactured by Tochem Products), MegaFuck F171, F173, R-30 (manufactured by Dainippon Ink), 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.). The use ratio of these surfactants is preferably 0.01 to 2 parts by mass, 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 aligning agent.

Specific examples of the compound for improving the adhesion between the liquid crystal alignment film and the substrate include the following functional silane-containing compounds and epoxy group-containing compounds.
For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-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-to Ethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltri Methoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-amino Propyltrimethoxysilane, 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, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetra Glycidyl-2,4-hexanediol, N, N, N ′, N ′,-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N Examples include ', N',-tetraglycidyl-4,4'-diaminodiphenylmethane.

Furthermore, in addition to improving the adhesion between the substrate and the film, it is preferable to contain the following phenoplast type additives for the purpose of preventing electrical characteristics from being deteriorated by the backlight. Specific phenoplast type additives are shown below.

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

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal aligning agent of the present invention can be applied as a liquid crystal alignment film without applying an alignment treatment in a vertical alignment application or the like after being applied on a substrate and baked and then subjected to an alignment treatment by rubbing treatment or light irradiation. In this case, 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 polycarbonate substrate such as a polycarbonate substrate, or the like can be used. In addition, it is preferable to use a substrate on which an ITO electrode or the like for driving liquid crystal is formed from the viewpoint of simplification of the process. In the reflective liquid crystal display element, an opaque material such as a silicon wafer can be used as long as only one substrate is used. In this case, a material that reflects light, such as aluminum, can also be used.
The application method of the liquid crystal aligning agent is not particularly limited, but industrially, it is generally performed by a method such as screen printing, offset printing, flexographic printing, or inkjet. Other coating methods include dip, roll coater, slit coater, spinner and the like, and these may be used depending on the purpose.

Firing after applying the liquid crystal aligning agent on the substrate can be carried out by a heating means such as a hot plate at 50 to 300 ° C., preferably 80 to 250 ° C., and the solvent can be evaporated to form a coating film. If the thickness of the coating film formed after baking 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 be lowered. The thickness is preferably 10 to 100 nm. When the liquid crystal is horizontally 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 aligning agent of the present invention by the method described above, and then preparing a liquid crystal cell by a known method.

If an example of liquid crystal cell production is given, prepare a pair of substrates on which a liquid crystal alignment film is formed, spread spacers on the liquid crystal alignment film of one substrate, so that the liquid crystal alignment film surface is on the inside, Examples include a method of bonding the other substrate and injecting liquid crystal under reduced pressure, or a method of bonding a substrate after sealing the liquid crystal on the liquid crystal alignment film surface on which spacers are dispersed, and sealing. The thickness of the spacer is preferably 1 to 30 μm, more preferably 2 to 10 μm.

Hereinafter, examples will be given to describe the present invention more specifically, but the interpretation of the present invention is not limited to these examples. The abbreviations used in the examples and the method of property 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 amount of 1.1 mL and a cone rotor TE-1 (1 ° 34 ′, R24) at a temperature of 25 ° C. .

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

The pixel electrode of the third layer has a comb-like shape configured by arranging a plurality of “bow” -shaped electrode elements having a bent central portion. The width in the short direction of each electrode element is 3 μm, and the distance between the electrode elements is 6 μm. Since the pixel electrode forming each pixel is formed by arranging a plurality of bent-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 bends and resembles a bold “Koji”. Each pixel is divided vertically with a central bent portion as a boundary, and has a first region on the upper side of the bent portion and a second region on the lower side.

When the first region and the second region of each pixel are compared, the formation 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 element of the pixel electrode is formed to form an angle of + 10 ° (clockwise) in the first region of the pixel, and the pixel in the second region of the pixel. The electrode elements of the electrode 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 (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode is in the substrate plane. It is comprised so that it may become a mutually reverse direction.

Next, after the liquid crystal aligning agent is filtered through a 1.0 μm filter, an ITO film is formed on the back surface as the prepared substrate with electrodes and a counter substrate, and glass having columnar spacers with a height of 4 μm. Each of the substrates was spin coated. Subsequently, after drying on an 80 degreeC hotplate for 2 minutes, the polyimide film with a film thickness of 60 nm was obtained on each board | substrate by baking at 230 degreeC for 20 minutes. The polyimide film is rubbed with a rayon cloth in a predetermined rubbing direction (roll diameter 120 mm, rotation speed 500 rpm, moving speed 30 mm / sec, pushing amount 0.3 mm), and then irradiated with ultrasonic waves in pure water for 1 minute. And dried at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.

Using the obtained two types of substrates with liquid crystal alignment film, the rubbing directions are combined so that they are antiparallel, the periphery is sealed leaving the liquid crystal injection port, and an empty cell with a cell gap of 3.5 μm is formed. Produced. A liquid crystal (MLC-3019, manufactured by Merck & Co., Inc.) was vacuum-injected into the empty cell at room temperature, and the injection port was sealed to obtain an anti-parallel alignment liquid crystal cell. The obtained liquid crystal cell constitutes an FFS mode liquid crystal display element. Thereafter, the obtained liquid crystal cell was heated at 120 ° C. for 1 hour and allowed to stand overnight before being used for each evaluation.

<Evaluation of liquid crystal alignment>
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 of the liquid crystal cell and the counter electrode were short-circuited and left as it was for one day at room temperature. After leaving, the liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal, 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 darkest to the angle at which the first region became darkest was calculated as an angle Δ. Similarly, for the second pixel, the second area was compared with the first area, and a similar 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 alignment.

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

<Preparation of adhesive evaluation sample>
The liquid crystal aligning agent was filtered through a filter having a pore diameter of 1.0 μm, spin-coated on a glass substrate with a transparent electrode, dried on an 80 ° C. hot plate for 2 minutes, and then baked at 230 ° C. for 20 minutes to have a film thickness of 70 nm. A coating film was obtained. Two substrates thus obtained were prepared, and after spraying a 4 μm diameter bead spacer (manufactured by JGC Catalysts & Chemicals Co., Ltd., true ball, SW-D1) on the liquid crystal alignment film surface of one substrate, UV ( UV) curable adhesive was added dropwise. Next, bonding was performed so that the liquid crystal alignment film surface of the other substrate was inside, and the overlapping width of the substrates was 0.5 cm. At that time, the dropping amount of the sealing agent was adjusted so that the diameter of the sealing agent after bonding was about 3 mm. After fixing the two bonded substrates together with a clip, using a cut filter with a wavelength of 325 nm or less, irradiating 3.0 J of UV with a wavelength of 365 nm, and then thermally curing at 120 ° C. for 1 hour to evaluate adhesiveness A sample of was prepared.

<Measurement of adhesive strength>
After fixing the edge part of an up-and-down board | substrate with the desktop type | mold precision universal testing machine, the produced sample was pulled up and down from both ends of the board | substrate short side, and the pressure (N) at the time of peeling was measured. And adhesive force was evaluated using the value which normalized the pressure (N) with the area (mm < ² >) estimated from the measured diameter of the sealing compound. A 3 mm diameter seal fracture surface was observed. The case where the adhesion area of the seal cross section was more than half was judged as good, and the case where the adhesion area of the seal was less than half was judged as bad.

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

(Synthesis Example 2)
A 50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 0.73 g (2.58 mmol) of DA-1, 2.22 g (9.09 mmol) of DA-4, and 0.724 g of DA-6 ( 1.30 mmol) was weighed and 46.5 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, and then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 505.4 mPa · s). s, PAA-2).

(Synthesis Example 3)
A 50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 0.71 g (2.41 mmol) of DA-1, 2.06 g (8.40 mmol) of DA-4, and 0.724 g of DA-6 ( 1.30 mmol) was weighed, 46.9 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, and then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 456.1 mPa · s). s, PAA-3).

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

(Synthesis Example 5)
A 50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 0.71 g (2.60 mmol) of DA-1, 2.06 g (8.43 mmol) of DA-4, and 1.09 g of DA-6 ( 1.96 mmol) was weighed, 48.7 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, and then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 80.9 mPa · s). s, PAA-5).

(Synthesis Example 6)
A 50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 0.93 g (3.25 mmol) of DA-1, 1.91 g (7.82 mmol) of DA-4 and 1.09 g (1) of DA-6. .96 mmol) was weighed and 48.7 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, and then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 471.4 mPa · s). s, PAA-6).

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

(Synthesis Example 8)
A 50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 0.71 g (2.61 mmol) of DA-1, 1.91 g (7.82 mmol) of DA-4, and 1.45 g of DA-6 (2 .60 mmol) was weighed, 50.2 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, stirred for 2 hours at room temperature, then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 475.2 mPa · s). s, PAA-8).

(Synthesis Example 9)
A 50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 0.93 g (3.23 mmol) of DA-1, 1.74 g (7.12 mmol) of DA-4, and 1.45 g of DA-6 ( 2.61 mmol), 50.4 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, stirred for 2 hours at room temperature, and then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 451.6 mPa · s). s, PAA-9).

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

(Synthesis Example 11)
A 50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 0.71 g (2.59 mmol) of DA-1, 2.60 g (9.08 mmol) of DA-4, and 0.724 g of DA-6 ( 1.3 mmol), 50.0 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, stirred for 2 hours at room temperature, and then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 498.1 mPa · s). s, PAA-11).

(Synthesis Example 12)
A 500 mL four-necked flask equipped with a stirrer is placed in a nitrogen atmosphere, 22.3 g (0.112 mol) of DA-2 and 5.55 g (0.026 mol) of DA-3 are weighed, 442 g of NMP is added, and nitrogen is added. Was dissolved by stirring while feeding. While stirring this diamine solution, 26.3 g (0.105 mol) of CA-3 was added, and after stirring for 2 hours at 50 ° C., 6.18 g (0.032 mol) of acid dianhydride (CA-2) was added. 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 placed in 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 feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, and then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 550.1 mPa · s). s, PAA-13).

(Synthesis Example 14)
A 50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 2.86 g (11.7 mmol) of DA-4 and 0.724 g (1.3 mmol) of DA-6 were weighed, and 46.1 g of NMP was added. The solution was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 523.2 mPa · s). s, PAA-14).

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

(Synthesis Example 16)
A 50 mL four-necked flask with a stirrer was placed in a nitrogen atmosphere, 0.518 g (2.60 mmol) of DA-2 and 2.51 g (10.3 mmol) of DA-4 were weighed, and 42.3 g of NMP was added. The solution was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 531.5 mPa · s). s, PAA-16).

(Synthesis Example 17)
A 50 mL four-necked flask equipped with a stirrer is placed in a nitrogen atmosphere, 1.02 g (5.22 mmol) of DA-2 and 1.91 g (7.82 mmol) of DA-4 are weighed, and 41.4 g of NMP is added. The solution was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, and then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 542.2 mPa · s). s, PAA-17).

(Synthesis Example 18)
A 50 mL four-necked flask equipped with a stirrer was placed in 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, stirred for 2 hours at room temperature, then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 525.2 mPa · s). s, PAA-18).

(Synthesis Example 19)
A 50 mL four-necked flask with a stirrer was placed in a nitrogen atmosphere, 0.51 g (2.61 mmol) of DA-2 and 2.97 g (10.4 mmol) of DA-5 were weighed, and 47.2 g of NMP was added. The solution was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 547.1 mPa · s). s, PAA-19).

(Synthesis Example 20)
A 50 mL (liter) four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 0.73 g (2.50 mmol) of DA-1 and 2.54 g (10.4 mmol) of DA-4 were weighed, and NMP was measured. 46.5 g was added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, and then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 510.7 mPa · s). s, PAA-20).

(Synthesis Example 21)
A 50 mL four-necked flask equipped with a stirrer is placed in a nitrogen atmosphere, 0.773 g (2.58 mmol) of DA-1 and 2.98 g (10.4 mmol) of DA-5 are weighed, and 47.4 g of NMP is added. The solution was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, and then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 525.3 mPa · s). s, PAA-21).

(Synthesis Example 22)
A 50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 1.51 g (5.21 mmol) of DA-1 and 2.23 g (7.79 mmol) of DA-4 were weighed, and 47.7 g of NMP was measured. In addition, it was dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 2.71 g (12.4 mmol) of CA-1 was added, stirred for 2 hours at room temperature, then stirred at 50 ° C. for 24 hours to obtain a polyamic acid solution (viscosity: 510.4 mPa · s). s, PAA-22).

(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 were collected. To this, 11.3 g of the polyamic acid solution (PAA-12) obtained in Synthesis Example 12 was added, and while stirring, an NMP solution containing 13.9 g of NMP, 8.00 g of BCS, and 1% by weight of LS-4668 Was added, 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 were collected. To this, 11.3 g of the polyamic acid solution (PAA-12) obtained in Synthesis Example 12 was added, and while stirring, an NMP solution containing 13.9 g of NMP, 8.00 g of BCS, and 1% by weight of LS-4668 Was added, 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 aligning agents (AL-1) to (AL-21) of Examples 1 to 11 and Comparative Examples 1 to 10 obtained above, evaluation of liquid crystal alignment, pretilt angle, and evaluation of seal adhesion Went. The results are shown in Table 1.

The liquid crystal aligning agent of the present invention is used in a wide range of fields such as a narrow frame type, a liquid crystal display device for mobile use such as a smart phone and a mobile phone, and a large liquid crystal display device that requires high definition and low cost. Is done.
It should be noted that the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2016-168471 filed on August 30, 2016 are cited herein as disclosure of the specification of the present invention. Incorporate.

Claims

A diamine component containing a diamine having a structure represented by the following formula [1], a diamine having a structure represented by the following formula [2], and a diamine having a structure represented by the following formula [3]; A liquid crystal aligning agent comprising at least one polymer selected from the group consisting of a polyamic acid obtained by a reaction with a tetracarboxylic dianhydride component and a polyimide obtained by imidizing the polyamic acid.

(In the formula, A represents a heat-eliminable group that is replaced with a hydrogen atom by heating at a temperature of 150 to 300 ° C. The hydrogen atom of the benzene ring is an alkyl group having 1 to 3 carbon atoms, an alkoxy group, or a halogen group. M is an integer of 1 to 18, and when m is 3 to 18, there may be —O— between any carbon-carbon bonds. When it is an integer of 18 and n is 3 to 18, there may be —O— between any carbon-carbon bonds, * represents a bond.
2. The liquid crystal aligning agent according to claim 1, wherein the thermally leaving group is a tert-butoxycarbonyl group or a 9-fluorenylmethoxycarbonyl group.
The liquid crystal aligning agent according to claim 1 or 2, wherein the diamine having the structure represented by the formula [1] is a diamine represented by any of the following formulas. However, Boc in the formula represents a tert-butoxycarbonyl group.
The liquid crystal aligning agent according to any one of claims 1 to 3, wherein the diamine having the structure represented by the formula [2] is a diamine represented by any one of the following formulas.
The liquid crystal aligning agent according to any one of claims 1 to 4, wherein the diamine having the structure represented by the formula [3] is a diamine represented by any one of the following formulas. However, Boc in the formula represents a tert-butoxycarbonyl group.
The liquid crystal aligning agent according to any one of claims 1 to 5, wherein a content of the diamine having a structure represented by the formula [1] in the diamine component is 5 to 95 mol%.
The total content of the diamine having the structure represented by the formula [2] and the diamine having the structure represented by the formula [3] is 10 to 60 mol%, and the structure represented by the formula [2] 7. The liquid crystal aligning agent according to claim 1, wherein the content ratio (molar ratio) of the diamine having the structure represented by the formula [3] is 10:90 to 90:10. .
The liquid crystal aligning agent according to any one of claims 1 to 7, wherein the tetracarboxylic 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 aligning agent according to claim 8, wherein Z 1 is any one of structures represented by the following formulas [7a] to [7k].
A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 9.
A liquid crystal display element comprising the liquid crystal alignment film according to claim 10.
The liquid crystal display element according to claim 11, wherein the liquid crystal display element is a frame element having a narrow seal width between substrates.