KR20170109604A - Liquid crystal orienting agent, liquid crystal display element, and method for producing liquid crystal display element - Google Patents

Abstract

A liquid crystal aligning agent, a liquid crystal alignment film, a liquid crystal display element and a manufacturing method of a liquid crystal display element having good residual DC characteristics are provided. A liquid crystal display device comprising a pair of substrates each having a conductive film on which a liquid crystal aligning agent is applied and heated to form a coated film on a liquid crystal cell opposed to the coated film with the liquid crystal layer interposed therebetween, Wherein the liquid crystal aligning agent contains the following components (A), (B), and an organic solvent. Component (A): at least one polymer selected from the group consisting of a polyimide precursor having a side chain that vertically aligns the liquid crystal, and an imide of the polyimide precursor. (B): a polyimide precursor which is a reaction product of a tetracarboxylic acid dianhydride component and a diamine component including a tetracarboxylic acid dianhydride selected from the following formulas (1) and (1 '), and a polyimide precursor At least one kind of polymer selected from the group consisting of polyimide which is an imide of imide. However, the component (B) may be the same polymer as the component (A) when it has a side chain that vertically aligns the liquid crystal. (j, k is 0 or 1, and x and y are a single bond, a carbonyl group, etc.)

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal display element, and a method of manufacturing a liquid crystal display element,

The present invention relates to a liquid crystal aligning agent, a liquid crystal display element and a method for producing a liquid crystal display element which can be used for the production of a liquid crystal display element of a vertical alignment type which is produced by irradiating liquid crystal molecules with ultraviolet rays.

Among liquid crystal display devices of a system (also referred to as a vertical alignment (VA) system) in which liquid crystal molecules vertically aligned with respect to a substrate are caused to respond by an electric field, in a manufacturing process, ultraviolet rays are irradiated while a voltage is applied to the liquid crystal molecules Process.

In such a vertical alignment type liquid crystal display device, a photopolymerizable compound is added in advance to a liquid crystal composition and used together with a vertical alignment film such as polyimide to irradiate ultraviolet light while applying a voltage to the liquid crystal cell, A polymer sustained alignment (PSA) device (see Patent Document 1 and Non-Patent Document 1) is known.

Usually, the tilting direction of the liquid crystal molecules in response to an electric field is controlled by protrusions formed on the substrate, slits formed on the display electrodes, and the like. When a photopolymerizable compound is added to a liquid crystal composition and ultraviolet rays are irradiated while a voltage is applied to the liquid crystal cell, a polymer structure in which the direction in which the liquid crystal molecules are inclined is stored is formed on the liquid crystal alignment layer. The response speed of the liquid crystal display element is said to be faster than the method of controlling the tilt direction of the liquid crystal display element.

On the other hand, it has been reported that the response speed of a liquid crystal display element is also improved by adding a photopolymerizable compound not in a liquid crystal composition but in a liquid crystal alignment film (SC-PVA type liquid crystal display) (see Non-Patent Document 2). In recent years, high-speed response of a single layer of a PSA type liquid crystal panel has been studied. As a technique of this, a monofunctional liquid crystalline compound having at least one of an alkenyl group and a fluoroalkenyl group (hereinafter referred to as " alkenyl- ) Is introduced into the liquid crystal composition (see Patent Documents 2 to 5). However, when the alkenyl-based liquid crystal is introduced into the liquid crystal composition, the voltage holding ratio and the DC charge accumulation characteristics (residual DC characteristics) tends to deteriorate as the reliability decreases (refer to Patent Documents 6 to 9).

In particular, the deterioration of the residual DC characteristic causes an exposure which leads to deterioration (after-image) of the display characteristics of the liquid crystal display element. As the remained DC improvement method so far, it is known that acceleration of charge movement by electrostatic interaction such as salt formation of a carboxyl group and a nitrogen-containing aromatic heterocyclic ring or hydrogen bonding is known. However, in the case of using an alkenyl-based liquid crystal as an improvement method for residual DC, the fact that there is little knowledge is current state (see Patent Documents 10 to 12).

Japanese Patent Application Laid-Open No. 2003-307720 International Publication No. 2009/050869 Japanese Patent Application Laid-Open No. 2010-285499 Japanese Patent Application Laid-Open No. 9-104644 Japanese Patent Application Laid-Open No. 6-108053 European Patent No. 0 474 062 specification U.S. Patent No. 6,666,268 Japanese Patent Application Laid-Open No. 2014-240486 Japanese Laid-Open Patent Publication No. 2014-224260 Japanese Patent Application Laid-Open No. 9-316200 Japanese Patent Application Laid-Open No. 10-104633 Japanese Patent Application Laid-Open No. 8-76128

 K. Hanaoka, SID 04 DIGEST, P. 1200-1202  K. H. Y. -J. Lee, SID 09 DIGEST, P. 666-668

It is an object of the present invention to provide a liquid crystal display device capable of improving the response speed of a liquid crystal display element of a vertical alignment system and capable of improving the electrical characteristics and residual DC characteristics of the obtained liquid crystal display element, A liquid crystal alignment film, a liquid crystal display device, and a method of manufacturing a liquid crystal display device which can improve residual DC characteristics.

Means for Solving the Problems In order to solve the above problems, the present inventors have made extensive studies and found out that the above problems can be solved, thereby completing the present invention having the following points.

1. A liquid crystal display device comprising: a pair of substrates having a conductive film; a liquid crystal aligning agent applied on the conductive film; and a substrate on which a coating film is formed by heating is applied to a liquid crystal cell opposed to the above- A liquid crystal aligning agent for a display element, which comprises the following components (A), (B), and an organic solvent.

Component (A): at least one polymer selected from the group consisting of a polyimide precursor having a side chain that vertically aligns the liquid crystal, and an imide of the polyimide precursor.

(B): a polyimide precursor which is a reaction product of a tetracarboxylic acid dianhydride component and a diamine component including a tetracarboxylic acid dianhydride selected from the following formulas (1) and (1 '), and a polyimide precursor At least one kind of polymer selected from the group consisting of polyimide which is an imide of imide. However, the component (B) may be the same polymer as the component (A) when it has a side chain that vertically aligns the liquid crystal.

[Chemical Formula 1]

(Wherein j and k are each independently 0 or 1, and x and y are each independently a single bond, carbonyl, ester, phenylene, sulfonyl or amide group.)

2. The liquid crystal aligning agent according to 1 above, wherein the liquid crystal layer in the liquid crystal display element is a liquid crystal layer containing a liquid crystal compound having an alkenyl type liquid crystal.

3. The composition as described in the above 1 or 2, wherein the content ratio of the component (A) and the component (B) is in a mass ratio of the component (A): the component (B) = X: (10- ≪ / RTI >

4. The liquid crystal aligning agent according to any one of items 1 to 3, wherein the side chain for vertically orienting the liquid crystal in the component (A) is represented by the following formula (a).

(2)

(1, m and n each independently represents an integer of 0 or 1, and R ¹ represents an alkylene group having 2 to 6 carbon atoms, -O-, -COO-, -OCO-, -NHCO-, -CONH- , Or an alkylene-ether group having 1 to 3 carbon atoms; R ² , R ³ and R ⁴ each independently represent a phenylene group, a fluorine-containing phenylene group or a cycloalkylene group; R ⁵ represents a hydrogen atom, An alkyl group having 2 to 24 carbon atoms, a fluorine-containing alkyl group having 2 to 24 carbon atoms, a monovalent aromatic ring, a monovalent aliphatic ring, a monovalent heterocyclic ring, or a monovalent cyclic substituent composed thereof.

5. A liquid crystal alignment film having a film thickness of 5 to 300 nm obtained from the liquid crystal aligning agent described in any one of 1 to 4 above.

6. A liquid crystal display element comprising the liquid crystal alignment film as described in 5 above.

7. A liquid crystal aligning agent containing a component (A), a component (B) and an organic solvent described below is applied on the conductive film of a pair of substrates each having a conductive film, followed by heating to form a coated film A second step of constructing a liquid crystal cell by arranging a pair of substrates on which the coating film is formed so as to oppose the coating film so as to face each other with the liquid crystal layer interposed therebetween; and a third step of irradiating the liquid crystal cell with light Wherein the liquid crystal display element is a liquid crystal display element.

Component (A): at least one polymer selected from the group consisting of a polyimide precursor having side chains for vertically aligning liquid crystals, and polyimide as an imide of the polyimide precursor.

Component (B): a polyimide precursor which is a reaction product of a tetracarboxylic acid dianhydride component containing at least one tetracarboxylic acid dianhydride selected from the group consisting of the following formulas (1) and (1 ') and a diamine: , And a polyimide which is an imide of the polyimide precursor. However, the component (B) may be the same polymer as the component (A) when it has a side chain that vertically aligns the liquid crystal.

(3)

(Wherein, j, k, x and y are as defined above.)

8. The method for manufacturing a liquid crystal display element according to 7 above, wherein the liquid crystal layer is a liquid crystal layer containing a liquid crystal compound having an alkenyl type liquid crystal.

9. A method for producing a liquid crystal display element as described in 7 or 8 above, wherein an irradiation amount of ultraviolet light is 1 to 50 J / cm 2.

10. The method for manufacturing a liquid crystal display element according to any one of 7 to 9 above, wherein the liquid crystal display element is a vertically aligned type display element.

According to the present invention, it is possible to provide a vertical alignment type liquid crystal display element in which the response speed of liquid crystal is fast and the residual DC is small.

The liquid crystal aligning agent used in the production method of the present invention is a liquid crystal aligning agent for a vertically aligned liquid crystal display element containing the component (A), the component (B) and an organic solvent. However, the component (B) may be the same polymer as the component (A).

In the present invention, the liquid crystal aligning agent is a solution for preparing a liquid crystal alignment film, and the liquid crystal alignment film is a film for aligning the liquid crystal in a predetermined direction, in the present invention, in the vertical direction.

[Component (A)] [

The liquid crystal aligning agent of the present invention comprises at least one polymer selected from the group consisting of a polyimide precursor having a side chain for vertically orienting a liquid crystal as a component (A) and a polyimide as an imide of the polyimide precursor Lt; / RTI >

<Side Chain for Vertically Orienting Liquid Crystal>

The side chain for vertically orienting the liquid crystal is not limited as long as the liquid crystal can be oriented perpendicular to the substrate. Examples thereof include an alkyl group in the long chain, a group having a ring structure or branched structure in the middle of the long chain alkyl group, a steroid group, and a group in which a part or all of the hydrogen atoms of these groups are substituted with a fluorine atom. The side chain for vertically orienting the liquid crystal may be directly bonded to the main chain of the polyamic acid or the polyimide, or may be bonded via a suitable bonding group. Examples of the side chain for vertically orienting the liquid crystal include those represented by the following formula (a).

[Chemical Formula 4]

(In the formula (a), l, m and n each independently represent an integer of 0 or 1, and R ¹ represents an alkylene group having 2 to 6 carbon atoms, -O-, -COO-, -OCO-, R ² , R ³ and R ⁴ each independently represent a phenylene group, a fluorine-containing phenylene group or a cycloalkylene group, R ³ represents an alkylene group having 1 to 3 carbon atoms, ⁵ represents a hydrogen atom, an alkyl group having 2 to 24 carbon atoms, a fluorine-containing alkyl group having 2 to 24 carbon atoms, a monovalent aromatic ring, a monovalent aliphatic ring, a monovalent heterocyclic ring, or a monovalent macrocyclic substituent composed thereof.

R ¹ in the formula (a) is preferably -O-, -COO-, -CONH- or an alkylene-ether group having 1 to 3 carbon atoms from the viewpoint of ease of synthesis.

R ² , R ³ and R ⁴ in the formula (a) are preferably selected from the group consisting of l, m, n, R ² , R ³ and R ⁴ in the following Table 1, from the viewpoints of ease of synthesis and ability to orient the liquid crystal vertically. R &lt; ⁴ &gt; is preferred.

When at least one of l, m and n is 1, R ⁵ in the formula (a) is preferably a hydrogen atom, an alkyl group having 2 to 14 carbon atoms, or a fluorine-containing alkyl group having 2 to 14 carbon atoms, , A hydrogen atom, an alkyl group having 2 to 12 carbon atoms, or a fluorine-containing alkyl group having 2 to 12 carbon atoms. When l, m and n are all 0, R ⁵ is preferably an alkyl group having 12 to 22 carbon atoms, a fluorine-containing alkyl group having 12 to 22 carbon atoms, a monovalent aromatic ring, a monovalent aliphatic ring, , Or monovalent macrocyclic substituents thereof, more preferably an alkyl group having 12 to 20 carbon atoms or a fluorine-containing alkyl group having 12 to 20 carbon atoms.

The content of the side chain that vertically aligns the liquid crystal in the polyimide or polyimide precursor used in the present invention is not particularly limited as long as the liquid crystal alignment film can orient the liquid crystal vertically. However, in a liquid crystal display device having a liquid crystal alignment film, when the response speed of the liquid crystal is intended to be faster, the content of the side chain that vertically aligns the liquid crystal is preferably as small as possible .

Further, the ability of the polymer having a side chain to vertically orient liquid crystal, the ability to vertically align liquid crystal is different depending on the structure of the side chain that vertically aligns the liquid crystal. Generally, when the content of the side chain that vertically aligns the liquid crystal is increased, the ability to vertically align the liquid crystal is increased, and when it is decreased, it is decreased. The side chain having a cyclic structure tends to have a higher ability to vertically align the liquid crystal as compared with a side chain having no cyclic structure.

&Lt; Production method of component (A) &gt;

The method for producing the component (A), which is at least one kind of polymer selected from the group consisting of a polyimide precursor having a side chain that vertically aligns the liquid crystal and a polyimide obtained by imidizing the polyimide precursor, And is not particularly limited. For example, in the method of obtaining a polyamic acid by the reaction of a diamine and a tetracarboxylic acid dianhydride, a diamine having a side chain that vertically aligns the liquid crystal may be copolymerized with a tetracarboxylic acid dianhydride.

Examples of the diamine having a side chain that vertically aligns the liquid crystal include a long-chain alkyl group, a group having a cyclic structure or branched structure in the middle of the long-chain alkyl group, a steroid group, a group obtained by substituting a part or all of hydrogen atoms of these groups with a fluorine atom And the like as a side chain, for example, a diamine having a side chain represented by the above formula (a). More specifically, for example, diamines represented by the following formulas (2), (3), (4) and (5) can be mentioned, but the present invention is not limited thereto.

[Chemical Formula 5]

(The definitions of 1, m, n, and R ¹ to R ⁵ in the formula (2) are the same as those of the formula (a).)

[Chemical Formula 6]

(In the formulas (3) and (4), A ₁₀ represents -COO-, -OCO-, -CONH-, -NHCO-, -CH ₂ -, -O-, -CO- or -NH- , A ₁₁ represents a monovalent bond or a phenylene group, a represents the same structure as the side chain for vertically orienting the liquid crystal represented by the formula (a), and a 'represents the liquid crystal represented by the formula (a) Represents a divalent group having a structure in which one hydrogen atom or the like is missing from the same structure as the side chain in which the hydrogen atom is removed.

(7)

Of, A ₁₄ is an alkyl group, having 3 to 20 carbon atoms which may be substituted with a fluorine atom, A ₁₅ is 1,4-cyclohexyl, and xylene group or a 1,4-phenylene group, A ₁₆ (equation (5), oxygen atom or -COO- * is (provided that combined hand provided with an "*" are combined with a _15), a ₁₇ is a bond hand provided with an oxygen atom or -COO- * (However, the "*" (CH ₂ ) combines with a _2. an) and again, a ₁ is an integer of 0, or 1, ₂ a is an integer of 2 ~ 10, a ₃ represents an integer of 0 or 1.)

The bonding position of two amino groups (-NH ₂ ) in the formula (2) is not limited. Specifically, with respect to the coupler of the side chains, positions 2 and 3, positions 2 and 4, positions 2 and 5, positions 2 and 6, positions 3 and 4, positions 3 and 5 on the benzene ring . Among them, from the viewpoint of reactivity in the synthesis of polyamic acid, positions 2 and 4, positions 2 and 5, and positions 3 and 5 are preferable. When the ease of synthesis of the diamine is also considered, positions 2 and 4, or positions 3 and 5 are more preferable.

Specific examples of the structure of the formula (2) include, but are not limited to, diamines represented by the following formulas [A-1] to [A-24].

[Chemical Formula 8]

(In the formulas [A-1] to [A-5], A ₁ represents an alkyl group having 2 to 24 carbon atoms or a fluorinated alkyl group having 2 to 24 carbon atoms.)

[Chemical Formula 9]

(In the formulas [A-6] and [A-7], A ₂ represents -O-, -OCH ₂ -, -CH ₂ O-, -COOCH ₂ - or -CH ₂ OCO- and A ₃ is an alkyl group having 1 to 22 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, a fluorine-containing alkyl group having 1 to 22 carbon atoms, or a fluorine-containing alkoxy group having 1 to 22 carbon atoms.

[Chemical formula 10]

(In the formulas [A-8] to [A-10], A ₄ represents -COO-, -OCO-, -CONH-, -NHCO-, -COOCH ₂ -, -CH ₂ OCO-, -CH ₂ O-, -OCH ₂ -, or -CH ₂ -, and A ₅ is an alkyl group, an alkoxy group, a fluorine-containing alkyl group or a fluorine-containing alkoxy group having 1 to 22 carbon atoms.

(11)

(Wherein [A-11] and the equation [A-12], A ₆ is, -COO-, -OCO-, -CONH-, -NHCO- , -COOCH 2 -, -CH 2 OCO-, -CH 2 -OCH ₂ -, -CH ₂ -, -O-, or -NH-, A ₇ represents a fluorine group, a cyano group, a trifluoromethane group, a nitro group, an azo group, a formyl group, An acetoxy group, or a hydroxyl group.

[Chemical Formula 12]

(In the formulas [A-13] and [A-14], A ₈ is an alkyl group having 3 to 12 carbon atoms and the cis-trans isomer of 1,4-cyclohexylene is a trans isomer.

[Chemical Formula 13]

(In the formulas [A-15] and [A-16], A ₉ is an alkyl group having 3 to 12 carbon atoms and the cis-trans isomer of 1,4-cyclohexylene is a trans isomer.

[Chemical Formula 14]

[Chemical Formula 15]

[Chemical Formula 16]

Specific examples of the diamine represented by the formula (3) include diamines represented by the following formulas [A-25] to [A-30], but the present invention is not limited thereto.

[Chemical Formula 17]

(In the formulas [A-25] to [A-30], A ₁₂ represents -COO-, -OCO-, -CONH-, -NHCO-, -CH ₂ -, -O-, -NH-, and A ₁₃ represents an alkyl group having 1 to 22 carbon atoms or a fluorine-containing alkyl group having 1 to 22 carbon atoms.

Specific examples of the diamine represented by the formula (4) include diamines represented by the following formulas [A-31] to [A-32], but the present invention is not limited thereto.

[Chemical Formula 18]

Among these, [A-1], [A-2], [A-3], [A-4], [A- 5], and [A-2] are preferable from the viewpoints of the ability to vertically align liquid crystals, A-25], [A-26], [A-27], [A- 28], [A- 29], or [A-30] are preferred.

The diamine may be used alone or in combination of two or more thereof depending on the properties of the liquid crystal alignment film, such as liquid crystal alignability, pretilt angle, voltage holding characteristics, and accumulated charge.

The diamine having a side chain that vertically aligns the liquid crystal is preferably used in an amount of 5 to 50 mol% of the diamine component used in the synthesis of the polyamic acid (A) component, more preferably 10 To 40 mol%, particularly preferably 15 to 30 mol%. When the diamine having a side chain that vertically aligns the liquid crystal is used in an amount of 5 to 50 mol% of the diamine component used for the synthesis of the polyamic acid, this is particularly excellent in view of the fixation ability of the vertical alignment.

In addition, as long as the effect of the present invention is not impaired, the polyamic acid may be used in combination with other diamines other than the diamine having a side chain for vertically orienting the liquid crystal as the diamine component. Specific examples include p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m- , 4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 2,5-diaminophenol, 2,4-diaminophenol, , 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diaminobiphenyl, 3,3'-dimethyl- Diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-dicarboxy 4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-biphenyl, 3,3'-trifluoromethyl-4,4'- Diaminobiphenyl, 3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, 4,4'-diaminodiphenylmethane, 3'- , 3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2'-diaminodiphenylmethane, 2,3'-diamino Diaminodiphenyl ether, 2,2'-diaminodiphenyl ether, 2,2'-diaminodiphenyl ether, 2,2'-diaminodiphenyl ether, 2,3,4'-diaminodiphenyl ether, Bis (4-aminophenyl) silane, dimethyl-bis (4-aminophenyl) silane, -Aminophenyl) silane, dimethyl-bis (3-aminophenyl) silane, 4,4'-thiodianiline, 3,3'- thiodianiline, 4,4'- diaminodiphenylamine, - diaminodiphenylamine, 3,4'-diaminodiphenylamine, 2,2'-diaminodiphenylamine, 2,3'-diaminodiphenylamine, N-methyl (4,4'-dia (3,3'-diaminodiphenyl) amine, N-methyl (3,4'-diaminodiphenyl) amine, N-methyl (2,2'-diaminodiphenyl) Phenyl) amine, N-methyl (2,3'-diaminodiphenyl) amine, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,4'- 1,4-diaminonaphthalene, 2,2'-diaminobenzophene , 2,3'-diaminobenzophenone, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 1,8-diaminonaphthalene, Bis (4-aminophenyl) ethane, 1,2-bis (3-aminophenyl) ethane, 2,6-diaminonaphthalene, 2,6-diaminonaphthalene, Bis (4-aminophenyl) propane, 1,3-bis (3-aminophenyl) propane, 1,4- Butene, bis (3,5-diethyl-4-aminophenyl) methane, 1,4-bis (4-aminophenoxy) benzene, Bis (4-aminophenyl) benzene, 1,4-bis (4-aminophenoxy) benzene, , 4'- [1,4-phenylenebis (methylene)] dianiline, 4,4 '- [1,3-phenylenebis (methylene)] dianiline, 3,4' - [ (Methylene)] dianiline, 3,4 '- [1,3-phenylenebis (methylene)] dianiline, Phenylenebis (methylene)] dianiline, 1,4-phenylenebis [(4 (4-phenylenebis -Aminophenyl) methanone], 1,4-phenylenebis [(3-aminophenyl) methanone], 1,3-phenylenebis [ Phenylene bis (3-aminophenyl) methanone], 1,4-phenylene bis (4-aminobenzoate), 1,4-phenylene bis (3-aminobenzoate) Aminobenzoate), bis (3-aminophenyl) terephthalate, bis (4-aminophenyl) iso (4-aminobenzamide), N, N '- (1,3-phenylene) bis (4-aminophenyl) (Aminobenzamide), N, N '- (1,4-phenylene) bis (3-aminobenzamide), N, N' N, N'-bis (4-aminophenyl) terephthalamide, N, N'- Bis (3-aminophenyl) isophthalamide, N, N'-bis (4-aminophenyl) isophthalamide, Bis (4-aminophenoxy) phenyl] propane, 2,2'-bis [4 Bis (3-aminophenoxy) phenyl] hexafluoropropane, 2,2'-bis (4-aminophenyl) hexafluoropropane, 2,2'- Bis (3-aminophenyl) propane, 2,2'-bis (3-aminophenyl) propane, Bis (4-aminophenyl) cyclohexane, 3,5-diaminobenzoic acid, 2,5-diaminobenzoic acid, bis (4- Bis (4-aminophenoxy) propane, 1, 3-bis (3-aminophenoxy) 4-bis (4-aminophenox Butene, 1,4-bis (3-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, Bis (4-aminophenoxy) hexane, 1,7-bis (3-aminophenoxy) hexane, Heptane, 1,8-bis (4-aminophenoxy) octane, 1,8-bis (3-aminophenoxy) octane, Bis (4-aminophenoxy) undecane, 1,10-bis (4-aminophenoxy) decane, , Aromatic diamines such as 1,11-bis (3-aminophenoxy) undecane, 1,12-bis (4-aminophenoxy) dodecane and 1,12-bis (3-aminophenoxy) dodecane; Alicyclic diamines such as bis (4-aminocyclohexyl) methane and bis (4-amino-3-methylcyclohexyl) methane; 1,3-diaminopropane, Aminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diamine Aliphatic diamines such as octane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane and 1,12-diaminododecane; 1,3-bis [2- aminophenyl) ethyl] urea, 1,3-bis [2- (p-aminophenyl) ethyl] -1-tertiarybutyloxycarbonylurea and the like; diamines having urea structure such as Np- diamines having a nitrogen-containing unsaturated heterocyclic structure such as p-aminophenyl (tertiarybutyloxycarbonyl) aminomethylpiperidine, N-tertiarybutoxycarbonyl-N- (2- (B-1) to (B-5) described in the item of the component (B) described below, such as a diamine having an N-Boc group such as N- One kind of diamine and diamines exemplified as specific examples thereof, and the like.

Examples of other diamines include diamines having a photoreactive side chain containing at least one selected from the group consisting of a methacryl group, an acryl group, a vinyl group, an allyl group, a coumarin group, a styryl group, and a cinnamoyl group, And a diamine having a site where radicals are generated in the side chain.

Specifically, for example, the diamine having a photoreactive side chain may be a diamine represented by the following general formula (6), but is not limited thereto.

[Chemical Formula 19]

(In the formula (6), R ⁶ represents a single bond, -CH ₂ -, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-, -N (CH ₃ ) -, -CON (CH ₃ ) - or -N (CH ₃ ) CO-, and R ⁷ represents a single bond or an alkyl having 1 to 20 carbon atoms which is substituted by an unsubstituted or fluorine atom And -CH ₂ - in the alkylene group may be optionally substituted with -CF ₂ - or -CH═CH-, and in the case where any of the groups shown below are not adjacent to each other, these groups may be substituted; -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, a divalent carbon ring, or a divalent heterocyclic ring, R ⁸ represents a photoreactive group selected from the following formulas.

[Chemical Formula 20]

The bonding position of two amino groups (-NH ₂ ) in the formula (6) is not limited. Specifically, with respect to the coupler of the side chains, positions 2 and 3, positions 2 and 4, positions 2 and 5, positions 2 and 6, positions 3 and 4, positions 3 and 5 on the benzene ring . Among them, from the viewpoint of reactivity in the synthesis of polyamic acid, positions 2 and 4, positions 2 and 5, and positions 3 and 5 are preferable. When the ease of synthesis of the diamine is also considered, positions 2 and 4, or positions 3 and 5 are more preferable.

Specific examples of the diamine having a photoreactive group containing at least one member selected from the group consisting of a methacryl group, an acrylic group, a vinyl group, an allyl group, a coumarin group, a styryl group and a cinnamoyl group include the following compounds But is not limited thereto.

[Chemical Formula 21]

(Wherein J ¹ is a bonding group selected from a single bond, -O-, -COO-, -NHCO-, or -NH-, J ² is a single bond or a carbon number An alkylene group having 1 to 20 carbon atoms.

The diamine having a site which is decomposed by irradiation with ultraviolet rays and which generates radicals as a side chain includes diamines represented by the following general formula (7), but is not limited thereto.

[Chemical Formula 22]

(Wherein Ar represents an aromatic hydrocarbon group selected from phenylene, naphthylene and biphenylene, they may be substituted with an organic group, and a hydrogen atom may be substituted with a halogen atom.) R ⁹ and R ¹⁰ may be the same or different, , T ₁ and T ₂ each independently represent a single bond, -O-, -S-, -COO-, -OCO-, -NHCO-, -NHCO-, -NHCO-, _{-CONH-, -NH-, -CH 2 O-,} -N (CH 3) -, -CON (CH 3) - a, or -N (CH ₃₎ CO-, S is a single bond, or unsubstituted or An alkylene group having 1 to 20 carbon atoms substituted with a fluorine atom (with the proviso that -CH ₂ - or CF ₂ - of the alkylene group may be optionally substituted with -CH═CH-, and any of the following groups may be adjacent to each other -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, a divalent carbon ring, or a divalent heterocyclic ring) , Q represents the following structure .

(23)

(Wherein R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ¹¹ represents -CH ₂ -, -NR-, -O-, or -S-).

The bonding position of two amino groups (-NH ₂ ) in the formula (7) is not limited. Specifically, with respect to the coupler of the side chains, positions 2 and 3, positions 2 and 4, positions 2 and 5, positions 2 and 6, positions 3 and 4, positions 3 and 5 on the benzene ring . Among them, from the viewpoint of reactivity in the synthesis of polyamic acid, positions 2 and 4, positions 2 and 5, and positions 3 and 5 are preferable. When the ease of synthesis of the diamine is also considered, positions 2 and 4, or positions 3 and 5 are more preferable.

The structure represented by the following formula is most preferable in view of ease of synthesis, height of general-purpose properties, characteristics, etc., but is not limited thereto.

&Lt; EMI ID =

(Wherein n is an integer of 2 to 8)

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

In the synthesis of polyamic acid, the tetracarboxylic acid dianhydride to be reacted with the above-mentioned diamine component is not particularly limited. Specific examples include pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7-anthracene tetracarboxylic acid, 1,2,5,6-anthracene tetracarboxylic acid, 3,3 ', 4,4'-biphenyltetracarboxylic acid, 2,3,3 (3,4-dicarboxyphenyl) ether, 3,3 ', 4,4'-benzophenonetetracarboxylic acid, bis (3,4-dicarboxyphenyl) Bis (3,4-dicarboxyphenyl) propane, 1,1,1,3,3,3-hexafluoro-2,2 (3,4-dicarboxyphenyl) propane, bis (3,4-dicarboxyphenyl) dimethylsilane, bis (3,4-dicarboxyphenyl) diphenylsilane, 2,3,4,5- Carboxylic acid, 2,6-bis (3,4-dicarboxyphenyl) pyridine, 3,3 ', 4,4'-diphenylsulfone tetracarboxylic acid, 3,4,9,10- A carboxylic acid, 1,3-diphenyl-1,2,3,4-cyclobutanetetracar Oxydipetetracarboxylic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, 1,2,4,5-cyclohexane Tetracarboxylic acid, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane tetracarboxylic acid, 1,2-dimethyl-1,2,3,4-cyclobutane tetracarboxyl Acid, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic acid, 1,2,3,4-cycloheptane tetracarboxylic acid, 2,3,4,5-tetrahydrofuran tetra Carboxylic acid, 3,4-dicarboxy-1-cyclohexylsuccinic acid, 2,3,5-tricarboxycyclopentylacetic acid, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene Succinic acid, bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic acid, bicyclo [4,3,0] nonane-2,4,7,9-tetracarboxylic acid, Bicyclo [4,4,0] decane-2,4,7,9-tetracarboxylic acid, bicyclo [4,4,0] decane-2,4,8,10-tetracarboxylic acid, tricyclo [6.3.0.0 &lt; 2,6 &gt;] undecane-3,5,9,11-te 1,2,4-butanetetracarboxylic acid, 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydrinaphthalene- 1,2-dicarboxylic acid, bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic acid, 5- (2,5-dioxotetrahydrofuryl) Methyl-3-cyclohexane-1,2-dicarboxylic acid, tetracyclo [6,2,1,1,0,2,7] dodeca-4,5,9,10-tetracarboxylic Anhydride of a tetracarboxylic acid such as an acid, 3,5,6-tricarboxy norbornane-2: 3,5: 6 dicarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, . Of course, the tetracarboxylic acid dianhydride may be used alone or in combination of two or more, depending on the properties such as liquid crystal aligning property, voltage holding property, and accumulated charge when the liquid crystal alignment film is used.

In order to obtain the polyamic acid by reacting the raw diamine (also referred to as the "diamine component") with the tetracarboxylic acid dianhydride (also referred to as "tetracarboxylic acid dianhydride component") as the raw material, Can be used. Generally, the diamine component and the tetracarboxylic acid dianhydride component are reacted in an organic solvent. The reaction between the diamine component and the tetracarboxylic acid dianhydride component is advantageous in that it proceeds relatively easily in an organic solvent and does not generate any by-products.

The organic solvent used in the reaction is not particularly limited as long as it dissolves the produced polyamic acid. In addition, even if the organic solvent does not dissolve the polyamic acid, the organic solvent may be mixed with the solvent in the range that the produced polyamic acid is not precipitated. Further, the moisture in the organic solvent inhibits the polymerization reaction and further causes the hydrolysis of the produced polyamic acid, so that the organic solvent is preferably dehydrated and dried.

Examples of the organic solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, N-methylformamide, Dimethyl-2-imidazolidinone, 3-methoxy-N, N-dimethylpropanamide, N-methylcaprolactam, dimethylsulfoxide , Tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide,? -Butyrolactone, isopropyl alcohol, methoxymethyl pentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, Ketones, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, butyl 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 Propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol, diethylene glycol monoacetate, di Ethylene glycol dimethyl ether, diethylene glycol diethyl 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, ethylisobutyl ether, diisobutyl Rhen, amyl acetate, butyl N-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, isobutyl ketone, , Methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methylethyl 3-ethoxypropionate, Methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 2- 1-hexanol, and the like. These organic solvents may be used alone or in combination.

When the diamine component and the tetracarboxylic acid dianhydride component are reacted in an organic solvent, the solution in which the diamine component is dispersed or dissolved in an organic solvent is stirred and the tetracarboxylic acid dianhydride component is dispersed or dissolved in the organic solvent as it is A method of adding a diamine component to a solution in which a tetracarboxylic acid dianhydride component is dispersed or dissolved in an organic solvent, a method of alternately adding a tetracarboxylic acid dianhydride component and a diamine component, and the like Any of these methods may be used. In the case where the diamine component or the tetracarboxylic acid dianhydride component is composed of a plurality of compounds, they may be reacted in advance in a mixed state, or they may be sequentially reacted individually, and the low- May be used.

The temperature at which the diamine component and the tetracarboxylic acid dianhydride component are reacted can be selected arbitrarily, and is, for example, in the range of -20 to 150 ° C, preferably -5 to 100 ° C. The reaction can be carried out at an arbitrary concentration. For example, the total amount of the diamine component and the tetracarboxylic acid dianhydride component relative to the reaction solution is 1 to 50 mass%, preferably 5 to 30 mass%.

The ratio of the total number of moles of the tetracarboxylic acid dianhydride component to the total moles of the diamine component in the above polymerization reaction can be selected in accordance with the molecular weight of the polyamic acid to be obtained. As in the case of the usual polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the produced polyamic acid. The preferable range is 0.8 to 1.2.

The method for synthesizing the polyamic acid to be used in the present invention is not limited to the above-mentioned method, and a tetracarboxylic acid having a corresponding structure or a tetracarboxylic acid having a corresponding structure may be used in place of the tetracarboxylic acid dianhydride, The corresponding polyamic acid can also be obtained by reacting a tetracarboxylic acid derivative such as a tetracarboxylic acid dihalide with a known method.

Examples of the method of imidizing the polyamic acid to form polyimide include thermal imidization in which a solution of polyamic acid is heated as it is, and catalyst imidization in which a catalyst is added to a solution of polyamic acid. The imidation rate from the polyamic acid to the polyimide is preferably 30% or more, more preferably 50 to 99%, from the viewpoint of increasing the voltage holding ratio. On the other hand, from the viewpoint of suppressing the whitening characteristics, that is, the precipitation of the polymer in the varnish, it is preferably 70% or less. When both characteristics are taken into account, 50 to 80% is more preferable.

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

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

In the case of recovering the polyamic acid or polyimide produced from the reaction solution of polyamic acid or polyimide, the reaction solution may be put into a poor solvent and precipitated. Examples of the poor solvent used for the formation of the precipitate include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene and water. The polymer precipitated by charging into a poor solvent can be recovered by filtration and then dried at normal temperature or under reduced pressure or by heating. In addition, when the polymer precipitated and recovered is redissolved in an organic solvent and the operation of reprecipitation and recovery is repeated 2 to 10 times, impurities in the polymer can be reduced. As the poor solvent at this time, for example, alcohols, ketones, hydrocarbons and the like can be mentioned, and when three or more poor solvents selected from these are used, the purification efficiency is further increased, which is preferable.

[Component (B)] [

The liquid crystal aligning agent of the present invention comprises, as the component (B), a tetracarboxylic acid dianhydride component containing at least one tetracarboxylic acid dianhydride selected from the group consisting of the above-mentioned formulas (1) and (1 ' And at least one polymer selected from the group consisting of a polyimide precursor obtained by the reaction of a diamine and a diamine and a polyimide obtained by imidizing the polyimide precursor.

When a liquid crystal alignment film having at least one tetracarboxylic acid dianhydride selected from the group consisting of the above-mentioned formulas (1) and (1 ') is used as a raw material, it occurs between the liquid crystal and the liquid crystal alignment film by light irradiation By the interaction assumed, the residual DC characteristics can be improved.

Examples of the tetracarboxylic acid dianhydride selected from the above formulas (1) and (1 ') include, but are not limited to, the following compounds.

(25)

At least one tetracarboxylic acid dianhydride selected from the group consisting of the above-mentioned formulas (1-1) to (1-5) is a tetracarboxylic acid dianhydride component used for the synthesis of the polyamic acid (B) It is preferable to use an amount of 10 to 100% It is more preferable to use 10 to 60%. More preferably, at least one tetracarboxylic acid 2 selected from the group consisting of the formulas (1-1), (1-3) and (1-5) It is preferable that the anhydride is used in an amount of 10 to 40 mol%, more preferably 20 to 40 mol%, of the entire tetracarboxylic acid dianhydride component used in the synthesis of the component (B).

Further, as long as the effect of the present invention is not impaired, other tetracarboxylic acid dianhydrides described in the component (A) may be used as a raw material for the component (B). For example, the tetracarboxylic acid dianhydride having an aliphatic group or an alicyclic group is used in an amount of 0 to 90 mol% of the tetracarboxylic acid dianhydride component used in the synthesis of the polyamic acid (B) component desirable.

The polymer as the component (B) may be at least one kind of diamine selected from the group consisting of the following formulas (B-1) to (B-5) as a raw material.

(26)

(Wherein Y ₁ represents a secondary amine, a tertiary amine, or a monovalent organic group having a heterocyclic structure, and Y ₂ represents a secondary amine, a tertiary amine, or a divalent organic group having a heterocyclic structure. )

At least one diamine having a specific polar structure selected from the above-mentioned formulas (B-1) to (B-5) is used, and further, a diamine having a carboxyl group and a diamine having a nitrogen- , The charge transfer is promoted by electrostatic interaction such as salt formation or hydrogen bonding, so that residual DC characteristics can be improved.

Examples of the at least one diamine selected from the group consisting of the above-mentioned formulas (B-1) to (B-5) include the following diamines, but are not limited thereto.

(27)

The polymer as the component (B) may be a diamine having a side chain that vertically aligns the liquid crystal used as the component (A), or other diamine described in the above-mentioned component (A).

At least one kind of diamine selected from the group consisting of the above-mentioned formulas (B-1) to (B-5) is an amount of 10 to 80 mol% of the diamine component used for the synthesis of the component (B) , And it is more preferable to use 20 to 70 mol%. More preferably, among the diamines exemplified above, 3,5-diaminobenzoic acid and 3,5-diamino-N- (pyridin-3-ylmethyl) benzamide Is used in an amount of 20 to 70 mol% of the total diamine component used in the synthesis of the component (B).

As a method for producing the component (B), at least one kind of tetracarboxylic acid dianhydride selected from the group consisting of the above-mentioned formulas (1) and (1 '), and further, other tetracarboxylic acid A tetracarboxylic acid dianhydride component containing an acid dianhydride and a diamine component may be reacted to obtain a polyimide precursor or polyimide.

The method for producing the component (B) is not limited to the use of at least one tetracarboxylic acid dianhydride selected from the group consisting of the above-mentioned formulas (1) and (1 ' Manufacturing method &quot;.

[Liquid crystal aligning agent]

As described above, the liquid crystal aligning agent of the present invention is a liquid crystal aligning agent comprising at least one kind selected from the group consisting of a polyimide precursor having a side chain for vertically orienting a liquid crystal and an imide of the polyimide precursor A reaction product of a tetracarboxylic acid dianhydride component comprising a polymer (A) component and at least one tetracarboxylic acid dianhydride selected from the group consisting of the above formulas (1) and (1 ') and diamine (B) which is at least one polymer selected from the group consisting of a polyimide precursor and a polyimide which is an imide of the polyimide precursor, and an organic solvent.

The total content of the component (A) and the component (B) in the liquid crystal aligning agent of the present invention is not particularly limited, but is preferably from 1 to 20 mass%, more preferably from 3 to 15 mass% Is 3 to 10% by mass.

The content ratio of the component (A) to the component (B) is not particularly limited, And preferably from 2: 8 to 8: 2. However, the component (B) may be the same polymer as the component (A) by having a side chain that vertically aligns the liquid crystal.

The liquid crystal aligning agent of the present invention may contain a polymer other than the component (A) and the component (B). At that time, the content of the other polymer in the entire polymer component is preferably 0.5 to 15% by mass, and more preferably 1 to 10% by mass.

The molecular weight of the polymer having the liquid crystal aligning agent is preferably in the range of from 0.1 to 10 parts by weight based on the weight average determined by GPC (Gel Permeation Chromatography) method, considering the strength of the liquid crystal alignment film obtained by applying the liquid crystal aligning agent, The molecular weight is preferably from 5,000 to 1,000,000, more preferably from 10,000 to 150,000.

The organic solvent contained in the liquid crystal aligning agent is not particularly limited and may be any one capable of dissolving or dispersing the components (A) and (B). For example, organic solvents such as those exemplified in the synthesis of the above polyamic acid can be mentioned. Among them, N-methyl-2-pyrrolidone,? -Butyrolactone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, -Dimethylpropanamide and the like are preferable from the viewpoint of solubility. In particular, N-methyl-2-pyrrolidone or N-ethyl-2-pyrrolidone is preferable, but two or more mixed solvents may be used.

It is also preferable to use a solvent which improves the uniformity and smoothness of the coating film in an organic solvent having high solubility of the component containing the liquid crystal aligning agent.

Examples of the solvent for improving the uniformity and smoothness of the coating film include isopropyl alcohol, methoxymethyl pentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, butyl cellosolve, Propylene glycol monoacetate, ethylene glycol monoacetate, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether, propylene glycol monoacetate, ethylene glycol monoacetate, ethylene glycol monoacetate, , Propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether , Dipropylene glycol monoacetate monomethyl ether, Propylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl- Propyl ether, diisobutyl ether, diisobutylene, amyl acetate, butyl butylate, butyl ether, diisobutyl ether, diisopropyl ether, diisopropyl ether, N-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol acetate Monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methylethyl 3-ethoxypropionate, 3- Methoxy-2-propanol, 1-ethoxy-2-propanol, 1-methoxypropionic acid, 3- 2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether- Ethyl lactate, n-butyl lactate, n-butyl lactate, isoamyl ester of lactic acid, 2-ethyl-1- (2-ethoxypropoxy) propanol, Hexanol, and the like. These solvents may be mixed with a plurality of kinds. When these solvents are used, it is preferably 5 to 80 mass%, more preferably 20 to 60 mass%, of the total solvent contained in the liquid crystal aligning agent.

The liquid crystal aligning agent may contain components other than those described above. Examples thereof include a compound which improves film thickness uniformity and surface smoothness when the liquid crystal aligning agent is applied, a compound which improves the adhesion between the liquid crystal alignment film and the substrate, and a compound which further improves the film strength of the liquid crystal alignment film .

Examples of the compound that improves film thickness uniformity and surface smoothness include a fluorine-based surfactant, a silicon-based surfactant, and a nonionic surface-active agent. More specifically, for example, EF301, EF303, EF352 (manufactured by TOKEM PRODUCTS CO., LTD.), Megafac F171, F173, R-30 (manufactured by Dainippon Ink and Chemicals Inc.), FLORAD FC430 and FC431 manufactured by Sumitomo 3M ), Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.). When these surfactants are used, the proportion thereof is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, based on 100 parts by mass of the total amount of the polymer contained in the liquid crystal aligning agent.

Specific examples of the compound improving the adhesion between the liquid crystal alignment layer and the substrate include a functional silane-containing compound and an epoxy group-containing compound. For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3 3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxy (2-aminoethyl) Aminopropyltriethoxysilane, N-trimethoxysilylpropyltriethoxysilane, N-trimethoxysilylpropyltriethoxysilane, N-trimethoxysilylpropyltriethoxysilane, N-trimethoxysilylpropyltriethoxysilane, Amine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl Acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N- Bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N- Aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neo Pentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6 Tetraglycidyl-2,4-hexanediol, N, N, N ', N', -tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglycidylamino Methyl) cyclohexane, N, N, N ', N', -tetraglycidyl-4,4'-diaminodiphenylmethane, 3- (N-allyl-N-glycidyl) aminopropyltrimethoxy Silane, 3- (N, N-diglycidyl) Aminopropyltrimethoxysilane, and the like.

In order to further improve the film strength of the liquid crystal alignment film, a phenol compound such as 2,2'-bis (4-hydroxy-3,5-dihydroxymethylphenyl) propane or tetra (methoxymethyl) You can. When these compounds are used, it is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of the total amount of the polymer contained in the liquid crystal aligning agent.

The liquid crystal aligning agent may be added with a dielectric material or a conductive material for the purpose of changing electrical characteristics such as dielectric constant and conductivity of the liquid crystal alignment film, as long as the effect of the present invention is not impaired.

This liquid crystal aligning agent is coated on the substrate and baked to form a liquid crystal alignment film for vertically aligning the liquid crystal.

The liquid crystal aligning agent of the present invention comprises at least one polymer selected from the group consisting of a polyimide precursor having a side chain for vertically orienting a liquid crystal and a polyimide obtained by imidizing the polyimide precursor, , A polyimide precursor obtained by reaction of a tetracarboxylic acid dianhydride component containing at least one tetracarboxylic acid dianhydride selected from the group consisting of the above-mentioned formulas (1) and (1 '), and (B) which is at least one kind of polymer selected from the group consisting of polyimides obtained by imidizing a polyimide precursor.

The substrate is not particularly limited as long as it is a substrate having high transparency, and a glass substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like can be used. It is preferable to use a substrate on which an ITO electrode or the like for liquid crystal driving is formed from the viewpoint of simplifying the process. In a reflection type liquid crystal display element, if it is only a substrate on one side, it may be opaque such as a silicon wafer. In this case, a material that reflects light such as aluminum can also be used as the electrode in this case.

The method of applying the liquid crystal aligning agent is not particularly limited, and examples thereof include screen printing, offset printing, flexographic printing, inkjet, dip, roll coater, slit coater and spinner.

The baking temperature of the coating film formed by applying the liquid crystal aligning agent is not limited and may be, for example, at any temperature of 100 to 350 ° C, preferably 120 to 300 ° C, more preferably 150 to 250 / RTI &gt; The firing can be performed by a hot plate, a hot air circulation path, an infrared ray lamp, or the like.

The thickness of the liquid crystal alignment film obtained by baking is not particularly limited, but is preferably 5 to 300 nm, and more preferably 10 to 100 nm.

A liquid crystal display element of the present invention comprises two substrates arranged to face each other, a liquid crystal layer formed between the substrate and the liquid crystal layer, and a liquid crystal cell having a liquid crystal alignment film formed by the liquid crystal aligning agent of the present invention The liquid crystal display device of the vertical alignment type is a liquid crystal display device having a vertical alignment method. Specifically, the liquid crystal aligning agent of the present invention is coated on two substrates and fired to form a liquid crystal alignment film. Two substrates are arranged so that the liquid crystal alignment films face each other, And a liquid crystal cell manufactured by irradiating ultraviolet rays. The liquid crystal cell of the vertical alignment type is a liquid crystal display device having a liquid crystal cell.

As described above, by applying ultraviolet rays to the liquid crystal alignment film and the liquid crystal layer using the liquid crystal alignment film formed by the liquid crystal aligning agent of the present invention, interaction occurs between the liquid crystal and the liquid crystal alignment film of the present invention, , It is considered that the liquid crystal display element is a liquid crystal display element in which exposure hardly occurs.

The substrate used in the liquid crystal display element of the present invention is not particularly limited as long as it is a substrate having high transparency, but is usually a substrate on which a transparent electrode for driving a liquid crystal is formed. Specific examples include the same substrates as those described in the liquid crystal alignment film.

The liquid crystal display of the present invention may be a substrate on which a conventional electrode pattern or a projection pattern is formed, but it has a liquid crystal alignment film formed using the liquid crystal aligning agent of the present invention, so that a line / A substrate having a structure in which a slit electrode pattern is formed and a counter substrate is not provided with a slit pattern or a projection pattern can be operated to simplify the process at the time of manufacturing the device and achieve a high transmittance.

In a high-performance device such as a TFT-type device, a device such as a transistor is formed between an electrode for liquid crystal driving and a substrate.

In the case of a transmissive liquid crystal display element, the above substrate is generally used, but in a reflective liquid crystal display element, it is possible to use an opaque substrate such as a silicon wafer only if it is a substrate on one side. At this time, a material such as aluminum that reflects light may be used for the electrode formed on the substrate.

The liquid crystal alignment film is formed by applying the liquid crystal aligning agent of the present invention on this substrate and then firing, and the details are as described above.

As the liquid crystal composition used in the liquid crystal display element of the present invention, a nematic liquid crystal having negative dielectric anisotropy can be used. For example, a dicyanobenzene-based liquid crystal, a pyridazine-based liquid crystal, a hepta base-based liquid crystal, an azeotropic liquid crystal, a biphenyl-based liquid crystal, a phenylcyclohexane-based liquid crystal, a terphenyl-based liquid crystal and the like can be used. It is also preferable to use an alkenyl-based liquid crystal in combination. As such alkenyl-based liquid crystals, conventionally known ones can be used. For example, a compound represented by the following formula, but the present invention is not limited thereto.

(28)

The liquid crystal composition constituting the liquid crystal layer of the liquid crystal display element of the present invention is not particularly limited as long as it is a liquid crystal material used in the vertical alignment method. For example, MLC-6608 and MLC-6609, liquid crystal compositions having a negative dielectric anisotropy, manufactured by Merck & Co., Inc. can be used. Further, MLC-3022 and MLC-3023 (including a photopolymerizable compound (RM)) manufactured by Merck & Co., Ltd., which is liquid crystal composition having negative dielectric anisotropy including an alkenyl-based liquid crystal, can be used.

As a method of sandwiching the liquid crystal layer between two substrates, known methods can be mentioned. For example, a pair of substrates on which a liquid crystal alignment film is formed is prepared, spacers such as beads are dispersed on a liquid crystal alignment film of one of the substrates, an adhesive is applied to the periphery of the substrate, The other substrate is bonded to each other, and the liquid crystal is injected under reduced pressure and sealed.

It is also possible to prepare a pair of substrates having a liquid crystal alignment film formed thereon, dispersing a spacer such as beads or the like on the liquid crystal alignment film of one of the substrates and then dropping the liquid crystal thereon so that the side on which the liquid crystal alignment film is formed is inward , And the other one of the substrates is bonded and sealed to form a liquid crystal cell. The thickness of the spacer at this time is preferably 1 to 30 占 퐉, more preferably 2 to 10 占 퐉.

The process of manufacturing the liquid crystal cell by irradiating the liquid crystal alignment layer and the liquid crystal layer with ultraviolet rays may be performed any time after liquid crystal sealing. The irradiation amount of the ultraviolet rays is, for example, 1 to 60 J / cm 2, preferably 40 J / cm 2 or less. When the ultraviolet ray irradiation amount is small, the reliability deterioration caused by the destruction of the members constituting the liquid crystal display element can be suppressed have.

The wavelength of the ultraviolet ray to be used is preferably 300 to 500 nm, more preferably 300 to 400 nm.

The irradiation of ultraviolet rays to the liquid crystal alignment film and the liquid crystal layer may be carried out while applying a voltage and maintaining this electric field. Here, the voltage applied between the electrodes is, for example, 5 to 30 Vp-p, preferably 5 to 20 Vp-p.

In the case of the PSA system in which a polymerizable compound is contained in a liquid crystal, when a UV light is irradiated while a voltage is applied to the liquid crystal alignment film and the liquid crystal layer, the polymerizable compound reacts to form a polymer, It is possible to speed up the response speed of the obtained liquid crystal display element. Also, by containing the component (B), residual DC characteristics are improved. At this time, the amount of ultraviolet radiation is small, and the ultraviolet ray irradiation time is reduced, which is preferable because the production efficiency is increased.

The liquid crystal aligning agent is not only useful as a liquid crystal aligning agent for producing a liquid crystal display element of a vertical alignment type such as a PSA type liquid crystal display or an SC-PVA type liquid crystal display, but also formed by rubbing treatment or photo alignment treatment The liquid crystal alignment layer can be preferably used.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. The abbreviations of the compounds used below are as follows.

(Acid anhydride)

BODA: bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic acid dianhydride.

CBDA: 1,2,3,4-Cyclobutane tetracarboxylic acid dianhydride.

PMDA: pyromellitic dianhydride.

[Chemical Formula 29]

(Diamine)

DBA: 3,5-diaminobenzoic acid

m-PDA: 1,3-Phenylenediamine

p-PDA: 1,4-Phenylenediamine

3AMPDA: 3,5-diamino-N- (pyridin-3-ylmethyl) benzamide

DDM: 4,4'-diaminodiphenylmethane

(30)

(31)

(32)

(In the formula DA-6, t represents a trans.)

<Solvent>

NMP: N-methyl-2-pyrrolidone.

BCS: butyl cellosolve.

&Lt; Measurement of polyimide molecular weight &

Apparatus: Room temperature gel permeation chromatography (GPC) apparatus (SSC-7200) manufactured by Senshu Scientific Corporation,

Column: Columns (KD-803, KD-805) manufactured by Shodex Co., Ltd.,

Column temperature: 50 캜,

Eluent: 30 mmol / l of lithium bromide-hydrate (LiBr.H ₂ O), 30 mmol / l of phosphoric acid-anhydrous crystal (o-phosphoric acid) as the additive, N, N'-dimethylformamide THF) 10 ml / l),

Flow rate: 1.0 ml / min,

Standard Samples for Calibration Curve TSK standard polyethylene oxide (molecular weight about 9,000,000, 150,000, 100,000, and 30,000) manufactured by Tosoh Corporation and polyethylene glycol (molecular weight about 12,000, 4,000, and 1,000) manufactured by Polymer Laboratories.

&Lt; Measurement of imidization rate &

20 mg of the polyimide powder was placed in an NMR sample tube (NMR sampling tube standard φ5 manufactured by Kusano Scientific Co., Ltd.), 1.0 ml of deuterated dimethyl sulfoxide (DMSO-d ₆ , 0.05 mass% TMS mixture) was added, . This solution was subjected to proton NMR measurement at 500 MHz using an NMR measuring instrument (JNW-ECA500, manufactured by Nippon Denshoku). A proton originating from a structure which is not changed before and after imidation is defined as a reference proton and the proton peak integrated value derived from the NH group of the amic acid appearing in the vicinity of 9.5 to 10.0 ppm and the peak integrated value of this proton is used And was obtained by the following equation. In the following formulas, x is the proton peak integrated value derived from the NH group of amic acid, y is the peak integrated value of the reference proton, and? Is the NH of amic acid in the case of polyamic acid (0% imidization rate) Is the ratio of the number of reference protons to one proton of the group.

Imidization ratio (%) = (1 -? X / y) x 100

&Lt; Synthesis Example 1 &

(3.30 g, 13.2 mmol), DA-3 (3.35 g, 8.80 mmol) and m-PDA (1.43 g, 13.2 mmol) were dissolved in NMP (29.8 g) and reacted at 60 ° C for 4 hours. Then, PMDA (1.85 g, 8.47 mmol) and NMP (9.93 g) were added and reacted at room temperature for 4 hours to obtain polyamic acid solution X1. The polyamic acid had a number average molecular weight of 13,000 and a weight average molecular weight of 39000.

NMP was added to the polyamic acid solution (25 g) to dilute it to 6.5 mass%, acetic anhydride (5.62 g) and pyridine (4.35 g) were added as an imidization catalyst and reacted at 80 ° C for 4 hours. The reaction solution was poured into methanol (300 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C to obtain polyimide powder A. The imidization ratio of the polyimide was 73%, and the number average molecular weight was 13000 and the weight average molecular weight was 39000.

NMP (18.0 g) was added to the obtained polyimide powder A (2.0 g), and the mixture was stirred and dissolved at 70 占 폚 for 12 hours. BCS (13.3 g) was added to this solution and stirred at room temperature for 2 hours to obtain liquid crystal aligning agent A1.

&Lt; Synthesis Example 2 &

(3.30 g, 13.2 mmol), DA-3 (3.35 g, 8.80 mmol) and m-PDA (1.43 g, 13.2 mmol) were dissolved in NMP (29.2 g) and reacted at 60 ° C for 4 hours. Then, CBDA (1.66 g, 8.47 mmol) and NMP (9.74 g) were added and reacted at 40 ° C for 4 hours to obtain a polyamic acid solution.

An imidization reaction was carried out in the same manner as in Synthesis Example 1 except that the polyamic acid solution (25 g) was used, and the post-reaction treatment was carried out to obtain a polyimide powder B. The imidization ratio of the polyimide was 73%, and the number average molecular weight was 13000 and the weight average molecular weight was 39000.

A liquid crystal aligning agent U1 was obtained in the same manner as in Synthesis Example 1 except that the obtained polyimide powder B (2.0 g) was used in place of the polyimide powder A.

Then, BODA (3.75 g, 15 mmol), DA-3 (1.90 g, 4.99 mmol) and m-PDA (2.16 g, 20.0 mmol) were dissolved in NMP (29.7 g) and reacted at 60 ° C for 4 hours Then, PMDA (2.10 g, 9.63 mmol) and NMP (9.92 g) were added and reacted at 40 ° C for 4 hours to obtain a polyamic acid solution.

An imidation reaction was carried out in the same manner as in Synthesis Example 1 except that the polyamic acid solution (25 g) was used, and the post-reaction treatment was carried out to obtain a polyimide powder C. The imidization ratio of the polyimide was 73%, and the number average molecular weight was 13000 and the weight average molecular weight was 39000.

A liquid crystal aligning agent L1 was obtained in the same manner as in Synthesis Example 1 except that the obtained polyimide powder C (2.0 g) was used in place of the polyimide powder A. [

5.0 g of the obtained liquid crystal aligning agent U1 as a first component and 5.0 g of a liquid crystal aligning agent L1 as a second component were mixed to obtain a liquid crystal aligning agent A2.

&Lt; Synthesis Example 3 &

PDA (14.6 g, 135 mmol) and 3AMPDA (38.16 g, 157 mmol) were dissolved in NMP (620 g) and treated with 55 C for 2 hours, CBDA (68.4 g, 349 mmol) and NMP (102 g) were added and reacted at 40 ° C for 4 hours to obtain a polyamic acid solution.

NMP was added to the polyamic acid solution (85 g) to dilute it to 6.5 mass%, acetic anhydride (18.87 g) and pyridine (5.85 g) were added as an imidization catalyst and reacted at 50 ° C for 3 hours. The reaction solution was poured into methanol (1000 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol, and dried at 100 ° C under reduced pressure to obtain polyimide powder D. The imidization ratio of the polyimide was 73%, and the number average molecular weight was 13000 and the weight average molecular weight was 39000.

The procedure of Synthesis Example 1 was repeated except that the obtained polyimide powder D (2.0 g) was used instead of the polyimide powder A to obtain liquid crystal aligning agent U2.

Then, BODA (123 g, 491 mmol), DBA (127 g, 837 mmol) and DA-1 (60.7 g, 148 mmol) were dissolved in NMP (1246 g) and reacted at 55 ° C for 2 hours. (50.0 g, 258 mmol) and NMP (202 g) were added to the reaction mixture, and the mixture was reacted at room temperature for 4 hours. A polyamic acid solution was obtained.

NMP was added to the polyamic acid solution (700 g) to dilute to 8 mass%, acetic anhydride (172 g) and pyridine (54 g) were added as imidation catalysts and reacted at 80 ° C for 4 hours. The reaction solution was poured into methanol (7000 g), and the obtained precipitate was separated by filtration. The precipitate was washed with methanol, and dried at 100 ° C under reduced pressure to obtain polyimide powder E. The imidization ratio of the polyimide was 73%, and the number average molecular weight was 13000 and the weight average molecular weight was 39000.

Except that the obtained polyimide powder E (2.0 g) was used in place of the polyimide powder A, the same treatment as in Synthesis Example 1 was carried out to obtain a liquid crystal aligning agent L2.

5.0 g of the obtained liquid crystal aligning agent U2 as a first component and 5.0 g of a liquid crystal aligning agent L2 as a second component were mixed to obtain a liquid crystal aligning agent A3.

&Lt; Synthesis Example 4 &

D-3 (2.74 g, 7.20 mmol), 3AMPDA (0.87 g, 3.59 mmol) and DA-2 (2.38 g, 7.20 mmol) were dissolved in NMP (29.7 g) The reaction was carried out at 60 ° C for 4 hours. Then, CBDA (2.10 g, 10.7 mmol) and NMP (9.89 g) were added and reacted at 40 ° C for 4 hours to obtain a polyamic acid solution.

NMP was added to the polyamic acid solution (25 g) to dilute it to 6.5 mass%, acetic anhydride (4.64 g) and pyridine (3.59 g) were added as an imidation catalyst and reacted at 80 ° C for 4 hours. The reaction solution was poured into methanol (300 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol, and dried at 100 ° C under reduced pressure to obtain polyimide powder F. The polyimide had an imidization rate of 74%, a number average molecular weight of 12,500 and a weight average molecular weight of 38,000.

A liquid crystal aligning agent U3 was obtained in the same manner as in Synthesis Example 1 except that the obtained polyimide powder F (2.0 g) was used instead of the polyimide powder A.

Then, BODA (3.15 g, 12.6 mmol), DA-3 (2.40 g, 6.31 mmol), DBA (1.28 g, 8.40 mmol) and 3AMPDA (1.25 g, 6.31 mmol) were dissolved in NMP (30.4 g) The reaction was carried out at 60 ° C for 4 hours. Then, PMDA (1.79 g, 8.19 mmol) and NMP (10.14 g) were added and reacted at room temperature for 4 hours to obtain a polyamic acid solution.

NMP was added to the polyamic acid solution (25 g) to dilute it to 6.5 mass%, acetic anhydride (5.26 g) and pyridine (4.08 g) were added as an imidation catalyst and reacted at 80 ° C for 4 hours. The reaction solution was poured into methanol (300 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol, and dried at 100 ° C under reduced pressure to obtain a polyimide powder G. The polyimide had an imidization rate of 75%, a number average molecular weight of 13,000, and a weight average molecular weight of 38,500.

A liquid crystal aligning agent L3 was obtained in the same manner as in Synthesis Example 1 except that the obtained polyimide powder G (2.0 g) was used in place of the polyimide powder A.

5.0 g of the obtained liquid crystal aligning agent U3 as a first component and 5.0 g of a liquid crystal aligning agent L3 as a second component were mixed to obtain a liquid crystal aligning agent A4.

&Lt; Synthesis Example 5 &

(1.90 g, 4.99 mmol) and m-PDA (2.16 g, 20.0 mmol) were dissolved in NMP (29.1 g) and reacted at 60 ° C for 4 hours. Then, CBDA (1.89 g, 9.64 mmol) and NMP (9.71 g) were added and reacted at 40 DEG C for 4 hours to obtain a polyamic acid solution.

An imidization reaction was carried out in the same manner as in Synthesis Example 1 except that the polyamic acid solution (25 g) was used, and the post-reaction treatment was carried out to obtain a polyimide powder H. The imidization ratio of the polyimide was 73%, and the number average molecular weight was 13000 and the weight average molecular weight was 39000.

A liquid crystal aligning agent L4 was obtained in the same manner as in Synthesis Example 1 except that the obtained polyimide powder H (2.0 g) was used in place of the polyimide powder A.

5.0 g of the liquid crystal aligning agent U1 obtained in Synthesis Example 2 as a first component and 5.0 g of the liquid crystal aligning agent L4 as a second component were mixed to obtain a liquid crystal aligning agent A5.

&Lt; Synthesis Example 6 &

BODA (4.12 g, 16.5 mmol), DA-5 (2.87 g, 6.60 mmol) and DBA (2.34 g, 15.4 mmol) were dissolved in NMP (24.8 g) and reacted at 80 ° C for 5 hours. Then, CBDA (1.01 g, 5.15 mmol) and NMP (8.30 g) were added and reacted at 40 占 폚 for 4 hours to obtain a polyamic acid solution.

NMP was added to the polyamic acid solution (38 g) to dilute it to 6 mass%, acetic anhydride (8.43 g) and pyridine (3.27 g) as an imidation catalyst were added and reacted at 100 ° C for 3 hours. This reaction solution was poured into methanol (484 g), and the obtained precipitate was separated by filtration. The precipitate was washed with methanol, and dried at 100 ° C under reduced pressure to obtain polyimide powder I. The imidization ratio of the polyimide was 73%, and the number average molecular weight was 13000 and the weight average molecular weight was 39000.

The procedure of Synthesis Example 1 was repeated except that the obtained polyimide powder I (2.0 g) was used instead of the polyimide powder A to obtain a liquid crystal aligning agent A6.

&Lt; Synthesis Example 7 &

NMP (10.0 g) was added to the polyamic acid solution X1 (10 g) obtained in Synthesis Example 1 and stirred at room temperature for 1 hour. BCS (13.3 g) was added and stirred at room temperature for 2 hours to obtain liquid crystal aligning agent A7 &Lt; / RTI &gt;

&Lt; Synthesis Example 8 &

1 (60.7 g, 148 mmol) was dissolved in NMP (1246 g) and reacted at 55 ° C for 2 hours. Then, CA-1 (50.6 g, 258 mmol) and NMP (202 g) were added to the reaction mixture, and the mixture was reacted at room temperature for 4 hours. A polyamic acid solution was obtained.

NMP was added to the polyamic acid solution (40 g) to dilute it to 8 mass%, acetic anhydride (9.15 g) and pyridine (2.84 g) were added as an imidation catalyst and reacted at 80 ° C for 3 hours. This reaction solution was poured into methanol (473 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol, and dried at 100 ° C under reduced pressure to obtain polyimide powder J. The polyimide had an imidization rate of 74%, a number average molecular weight of 13,500 and a weight average molecular weight of 40000.

A liquid crystal aligning agent L5 was obtained in the same manner as in Synthesis Example 1 except that the obtained polyimide powder J (2.0 g) was used in place of the polyimide powder A.

5.0 g of the liquid crystal aligning agent U2 obtained in Synthesis Example 3 as a first component and 5.0 g of the liquid crystal aligning agent L5 as a second component were mixed to obtain a liquid crystal aligning agent A8.

&Lt; Synthesis Example 9 &

DA-3 (1.45 g, 3.81 mmol), DA-1 (2.34 g, 5.70 mmol) and DBA (1.45 g, 9.53 mmol) were dissolved in NMP (30.4 g) After reacting at 55 占 폚 for 3 hours, CA-1 (2.04 g, 5.69 mmol) and NMP (8.17 g) were added and the mixture was reacted at room temperature for 4 hours. Further, CBDA (0.60 g, 3.06 mmol) g) was added and reacted at room temperature for 4 hours to obtain a polyamic acid solution.

NMP was added to the polyamic acid solution (40 g) to dilute it to 6.5 mass%, acetic anhydride (7.46 g) and pyridine (2.31 g) as an imidation catalyst were added and reacted at 80 ° C for 3 hours. The reaction solution was poured into methanol (465 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C to obtain a polyimide powder L. The polyimide had an imidization rate of 75%, a number average molecular weight of 13,000, and a weight average molecular weight of 39,500.

A liquid crystal aligning agent L6 was obtained in the same manner as in Synthesis Example 1 except that the obtained polyimide powder L (2.0 g) was used in place of the polyimide powder A. [

5.0 g of the liquid crystal aligning agent U2 obtained in Synthesis Example 3 as a first component and 5.0 g of the liquid crystal aligning agent L6 as a second component were mixed to obtain a liquid crystal aligning agent A9.

&Lt; Synthesis Example 10 &

BODA (2.25 g, 8.99 mmol), DA-2 (2.97 g, 8.99 mmol) and DA-3 (3.43 g, 9.01 mmol) were dissolved in NMP (34.6 g) and reacted at 60 ° C for 4 hours. Then, CBDA (1.75 g, 8.92 mmol) and NMP (6.99 g) were added and reacted at 40 ° C for 4 hours to obtain a polyamic acid solution.

NMP was added to the polyamic acid solution (40 g) to dilute it to 6.5 mass%, acetic anhydride (7.06 g) and pyridine (2.19 g) were added as imidation catalysts and reacted at 80 ° C for 4 hours. The reaction solution was poured into methanol (463 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol, and dried at 100 ° C under reduced pressure to obtain a polyimide powder M. The imidization ratio of the polyimide was 74%, the number average molecular weight was 12500, and the weight average molecular weight was 38,500.

A liquid crystal aligning agent U4 was obtained in the same manner as in Synthesis Example 1 except that the obtained polyimide powder M (2.0 g) was used in place of the polyimide powder A.

Then, BODA (1.20 g, 4.80 mmol), DBA (1.46 g, 9.59 mmol), 3AMPDA (1.74 g, 7.18 mmol) and DA-3 (2.74 g, 7.20 mmol) were dissolved in NMP (28.58 g) The reaction was carried out at 60 ° C for 2 hours. After that, the mixture was reacted at room temperature for 4 hours. Further, CBDA (2.78 g, 14.18 mmol) and NMP (11.1 g) were added, followed by addition of 4 Hour reaction to obtain a polyamic acid solution.

NMP was added to the polyamic acid solution (40 g) to dilute it to 6.5 mass%, acetic anhydride (8.90 g) and pyridine (2.76 g) were added as imidation catalysts and reacted at 80 ° C for 4 hours. The reaction solution was poured into methanol (472 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol, and dried at 100 ° C under reduced pressure to obtain polyimide powder N. The polyimide had an imidization rate of 74%, a number average molecular weight of 13,000, and a weight average molecular weight of 39,000.

A liquid crystal aligning agent L7 was obtained in the same manner as in Synthesis Example 1 except that the obtained polyimide powder N (2.0 g) was used in place of the polyimide powder A.

3.0 g of the obtained liquid crystal aligning agent U4 as a first component and 7.0 g of a liquid crystal aligning agent L7 as a second component were mixed to obtain a liquid crystal aligning agent A10.

&Lt; Synthesis Example 11 &

(2.74 g, 7.20 mmol) was dissolved in NMP (28.58 g) and treated at 60 &lt; 0 &gt; C with a solution of BODA (1.20 g, 4.80 mmol), DBA (1.46 g, 9.59 mmol), 3AMPDA (1.74 g, 7.18 mmol) For 2 hours. Thereafter, CA-2 (1.41 g, 4.79 mmol) and NMP (5.65 g) were added and reacted at room temperature for 4 hours. Further, CBDA (2.78 g, 14.18 mmol) and NMP (11.1 g) For 4 hours to obtain a polyamic acid solution.

NMP was added to the polyamic acid solution (40 g) to dilute it to 6.5 mass%, acetic anhydride (8.61 g) and pyridine (2.67 g) were added as imidation catalysts and reacted at 80 ° C for 4 hours. This reaction solution was poured into methanol (470 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C to obtain polyimide powder O. The imidization ratio of this polyimide was 75%, the number average molecular weight was 14,000, and the weight average molecular weight was 39000.

A liquid crystal aligning agent L8 was obtained in the same manner as in Synthesis Example 1 except that the obtained polyimide powder O (2.0 g) was used in place of the polyimide powder A. [

3.0 g of the liquid crystal aligning agent U4 obtained in Synthesis Example 10 as a first component and 7.0 g of a liquid crystal aligning agent L8 as a second component were mixed to obtain a liquid crystal aligning agent A11.

&Lt; Synthesis Example 12 &

5 (1.56 g, 3.59 mmol) and DA-7 (2.67 g, 5.40 mmol) were added to NMP (31.7 g), CA-3 (2.42 g, 10.8 mmol), DA- And reacted at 60 DEG C for 4 hours. Then, PMDA (1.30 g, 5.94 mmol) and NMP (5.20 g) were added and reacted at room temperature for 4 hours to obtain a polyamic acid solution.

NMP was added to the polyamic acid solution (40 g) to dilute it to 6.0 mass%, acetic anhydride (2.01 g) and pyridine (1.61 g) were added as imidation catalysts and reacted at 110 ° C for 4 hours. The reaction solution was poured into methanol (480 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C to obtain a polyimide powder P. The imidization ratio of this polyimide was 55%, and the number average molecular weight was 11000 and the weight average molecular weight was 32000.

NMP (18.0 g) was added to the obtained polyimide powder P (2.0 g) instead of the polyimide powder A, and the mixture was stirred and dissolved at 70 占 폚 for 12 hours. BCS (13.3 g) was added to this solution and stirred at room temperature for 2 hours to obtain liquid crystal aligning agent A12.

&Lt; Synthesis Example 13 &

5 (1.56 g, 3.59 mmol) and DA-7 (2.67 g, 5.40 mmol) were dissolved in NMP (31.7 g) in the presence of CA-3 (3.83 g, 17.1 mmol), DA- And reacted at 60 DEG C for 6 hours to obtain a polyamic acid solution.

NMP was added to the polyamic acid solution (40 g) to dilute to 6.0 mass%, acetic anhydride (2.07 g) and pyridine (1.60 g) were added as imidation catalysts and reacted at 110 ° C for 4 hours. The reaction solution was poured into methanol (480 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at 100 占 폚 to obtain polyimide powder Q. The imidization ratio of the polyimide was 55%, the number average molecular weight was 10,500, and the weight average molecular weight was 31,500.

NMP (18.0 g) was added to the resulting polyimide powder Q (2.0 g), and the mixture was stirred and dissolved at 70 占 폚 for 12 hours. BCS (13.3 g) was added to this solution and stirred at room temperature for 2 hours to obtain liquid crystal aligning agent U5.

Then, CA-3 (2.96 g, 13.2 mmol), DDM (3.49 g, 17.6 mmol) and DA-7 (2.18 g, 4.41 mmol) were dissolved in 34.5 g of NMP and reacted at 60 ° C for 4 hours . Then, PMDA (1.54 g, 7.04 mmol) and NMP (6.10 g) were added and reacted at room temperature for 4 hours to obtain polyamic acid solution X2. The number average molecular weight of the polyamic acid was 12,500 and the weight average molecular weight was 34,000.

NMP (10.0 g) was added to the obtained polyamic acid solution X2 (10 g), and the mixture was stirred at room temperature for 1 hour. BCS (13.3 g) was added and stirred at room temperature for 2 hours to obtain liquid crystal aligning agent L9.

5.0 g of the obtained liquid crystal aligning agent U5 as a first component and 5.0 g of a liquid crystal aligning agent L9 as a second component were mixed to obtain a liquid crystal aligning agent A13.

&Lt; Production of liquid crystal cell &

(Example A)

Using the liquid crystal aligning agent A1 obtained in Synthesis Example 1, a liquid crystal cell was produced in the following sequence. The liquid crystal aligning agent A1 obtained in Synthesis Example 1 was spin-coated on the ITO surface of the ITO electrode substrate having a pixel size of 100 mu m x 300 mu m and an ITO electrode pattern with a line / space of 5 mu m formed thereon, , And then fired in a hot-air circulating oven at 200 캜 for 20 minutes to form a liquid crystal alignment film having a thickness of 100 nm.

The liquid crystal aligning agent A1 was spin-coated on an ITO surface on which no electrode pattern was formed, dried for 90 seconds on a hot plate at 80 占 폚, and then baked in a hot air circulating oven at 200 占 폚 for 20 minutes, A liquid crystal alignment film of 100 nm was formed.

On the above two substrates, a bead spacer of 4 mu m was dispersed on the liquid crystal alignment film of one substrate, and then a sealing agent (solvent type thermosetting type epoxy resin) was printed thereon. Subsequently, the other side of the substrate on which the liquid crystal alignment film was formed was laminated with the previous substrate, and then the sealing agent was cured to prepare empty cells. A liquid crystal cell MLC-6608 (trade name, manufactured by Merck), which is a liquid crystal composition not containing an alkenyl liquid crystal, was injected into this empty cell by a low pressure injection method. The obtained liquid crystal cell was subjected to annealing (re-orienting treatment) for 30 minutes in a circulating oven at 110 ° C.

Thereafter, the liquid crystal cell was subjected to light irradiation under the following conditions, and the voltage holding ratio and residual DC were measured under the following conditions. For comparison, the voltage holding ratio and the residual DC were also measured for the liquid crystal cell not irradiated with light under the same conditions.

[Light irradiation]

UV light passed through a band-pass filter of 365 nm was irradiated from the outside of the liquid crystal cell at 6 J / cm 2 (using a USHIO Super High Mercury Lamp LL, and ORC UV Light Measure Model UV-M03A (Attachment: UV-35) to measure the illuminance.

[Voltage maintenance rate]

The obtained liquid crystal cell was measured using VHR-1A manufactured by Toyo Technica Co., Ltd. under the condition of 60 占 폚 for 60 占 퐏 in a voltage of 1 V under the temperature of 60 占 폚, and the ratio of the voltage held after 1667 ms was measured as the voltage holding ratio.

[Evaluation of Residual DC]

An AC voltage of 5.8 Vpp and a DC voltage of 1 V were applied to the liquid crystal cell after the measurement of the voltage holding ratio for 48 hours and the voltage (residual DC) generated in the liquid crystal cell was obtained by the flicker erase method immediately after the DC voltage was released. This value is an indicator of the afterimage characteristic, and when this value is ± 30 mV or less, it can be said that the afterimage characteristic is excellent.

(Example B, Comparative Example A, Reference Example A)

A liquid crystal cell irradiated with light was manufactured in the same manner as in Example A except that the liquid crystal aligning agent described in Table 2 was used in place of the liquid crystal aligning agent A1, and the voltage holding ratio and the residual DC were measured.

(Example 1)

A liquid crystal cell irradiated with light was produced in the same manner as in Example A except that MLC-3022 (trade name), which is a liquid crystal composition containing an alkenyl-based liquid crystal, was used in place of MLC-6608, Respectively.

(Examples 2 to 4 and 8 to 14)

A liquid crystal cell irradiated with light was manufactured in the same manner as in Example 1 except that the liquid crystal aligning agent described in Table 3 was used in place of the liquid crystal aligning agent A1, and the voltage holding ratio and residual DC were measured.

(Comparative Examples 1 and 2)

A liquid crystal cell irradiated with light was manufactured in the same manner as in Example 1 except that the liquid crystal aligning agent described in Table 3 was used in place of the liquid crystal aligning agent A1, and the voltage holding ratio and residual DC were measured.

(Example 5)

MLC-3023 (trade name, Merck), which is a liquid crystal composition containing an alkenyl-based liquid crystal and RM (photopolymerizable compound), was used instead of MLC-6608, liquid crystal aligning agent A2 was used in place of liquid crystal aligning agent A1, The same operation as in Example A was carried out except that the PSA treatment was carried out under the following conditions, and the liquid crystal cell irradiated with light was prepared, and the voltage holding ratio and residual DC were measured.

[PSA treatment]

UV light having passed through a 325 nm high pass filter was irradiated from the outside of the liquid crystal cell at a rate of 10 J / cm 2 while applying a DC voltage of 15 V (using a USHIO Super High Mercury Lamp LL and ORC UV Light Measure Model UV-M03A (Attachment: UV-35). Thereafter, UV (UV lamp: FLR40SUV32 / A-1) was irradiated for 30 minutes using a UV-FL irradiator manufactured by Toshiba Litech Co., Ltd. in a state in which no voltage was applied.

(Examples 15 to 19)

A liquid crystal cell subjected to the PSA treatment was produced in the same manner as in Example 5 except that the liquid crystal aligning agent described in Table 4 was used in place of the liquid crystal aligning agent A2, and the voltage holding ratio and residual DC were measured.

(Comparative Examples 3 to 4)

A liquid crystal cell subjected to the PSA treatment was produced in the same manner as in Example 5 except that the liquid crystal aligning agent described in Table 4 was used in place of the liquid crystal aligning agent A2, and the voltage holding ratio and residual DC were measured.

(Example 6)

The same operations as in Example A were carried out except that MLC-3022 (Merck & Co., Inc.), which is a liquid crystal composition containing an alkenyl-based liquid crystal, was used instead of MLC-6608 and liquid crystal aligning agent A2 was used in place of liquid crystal aligning agent A1 And the liquid crystal cell was subjected to annealing in a circulating oven at 150 캜 for 3 hours, and the voltage holding ratio and residual DC were measured.

(Example 7)

The same operations as in Example A were carried out except that MLC-3022 (Merck & Co., Inc.), which is a liquid crystal composition containing an alkenyl-based liquid crystal, was used instead of MLC-6608 and liquid crystal aligning agent A2 was used in place of liquid crystal aligning agent A1 The liquid crystal cell was annealed in a circulating oven at 150 캜 for 3 hours and again subjected to light irradiation under the same conditions, and the voltage holding ratio and residual DC were measured .

Table 2 shows the results of using MLC-6608, which is a conventional liquid crystal, which does not contain an alkenyl-based liquid crystal, as Examples A, B, and Comparative Example A and Reference Example A. In Comparative Example A and Reference Example A in which a polymer having a PMDA derived structural unit was not used, the accumulation of residual DC was suppressed in Reference Example A using a highly polar diamine, which is a conventional reduction method of residual DC .

On the other hand, also in Example A and Example B where a polymer having a PMDA-derived structural unit was used, residual DCs were reduced compared to Comparative Example A, although there was a difference in degree by the amount of introduction of the PMDA- Further reduction is seen by investigation.

As described above, in the case of MLC-6608 which is a liquid crystal composition containing no alkenyl-based liquid crystal, it is possible to reduce the amount of residual DCs accumulated by the conventional method, and also in a liquid crystal alignment film containing a polymer having a PMDA- , And can be reduced by light irradiation.

Table 3 shows the results of using MLC-3022, which is a liquid crystal composition containing an alkenyl-based liquid crystal. Compared with Table 2, it can be seen that the voltage holding ratio as a whole is lowered. In Comparative Example 1 and Comparative Example 2, also in Comparative Example 2 using the liquid crystal aligning agent A6, which had an effect on the residual DC in MLC-6608, the amount of residual DC accumulated was large regardless of whether or not light was irradiated. On the other hand, Example 1, Example 2, Example 3, Example 4, Example 8, Example 9, Example 10 and Example using a polymer having a structural unit derived from PMDA, CA-1 or CA- 11, Example 12, Example 13, and Example 14, residual DC in the unexamined irradiation was largely reduced by light irradiation although the accumulation amount was large in the same manner as in Comparative Example 2.

Table 4 shows the results of using MLC-3023, which is a liquid crystal composition containing an alkenyl-based liquid crystal and RM. As in Table 3, although the voltage holding ratio is lower than that of Table 2, in Comparative Examples 3 and 4, the accumulated amount of residual DC is large irrespective of whether PSA treatment is performed or not. However, in Example 5 and Examples 15 to 19 using a polymer having a structural unit derived from PMDA, CA-1 or CA-2, residual DC was significantly reduced by the PSA treatment.

Thus, when a liquid crystal composition containing an alkenyl-based liquid crystal is used, there is no effect by the conventional reduction method of residual DC, and a liquid crystal composition containing a polymer having a structural unit derived from PMDA, CA-1 or CA- By using the alignment film, the residual DC is reduced by performing the PSA treatment.

As in the examples shown in Tables 3 and 4, the factors capable of reducing the accumulation of residual DC by irradiating a polymer using PMDA-derived structural units were examined (Table 5).

In Example 5, light irradiation was performed using a liquid crystal aligning agent A2 containing a polymer having a PMDA-derived structural unit, and as a result, residual DC was reduced as compared with unirradiation. After the irradiation with light, annealing treatment was performed at 150 占 폚 for 3 hours, and as a result, accumulation of residual DC was observed to the same extent as the result of the irradiation with no light (Example 6).

It is considered that deterioration of the liquid crystal can not be considered as deterioration of the liquid crystal because there is almost no change in the voltage holding ratio before and after the annealing and the interaction between the liquid crystal and the liquid crystal alignment film is canceled by light irradiation. Further, as a result of conducting light irradiation again in this state (Example 7), the accumulation amount of residual DC was reduced again. From this point of view, it was revealed that the light irradiation caused an interaction between the liquid crystal and the liquid crystal alignment film, thereby reducing the amount of residual DC accumulated.

From the above, even when a low-reliability liquid crystal composition containing an alkenyl-based liquid crystal is used as in the embodiment, it is possible to obtain a liquid crystal composition containing a tetracarboxylic acid dianhydride (for example, PMDA) of the formula (1) , The accumulation of residual DC after the light irradiation or after the PSA treatment can be reduced by using the liquid crystal alignment film containing the polymer having the structural unit of the structural formula

The liquid crystal display element obtained in the present invention is useful as a liquid crystal display element of a vertical alignment type such as PSA type liquid crystal display or SC-PVA type liquid crystal display.

The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2015-22122 filed on February 6, 2015 are incorporated herein by reference and are hereby incorporated by reference.

Claims (10)

A liquid crystal display device comprising a pair of substrates each having a conductive film on which a liquid crystal aligning agent is applied and heated to form a coated film on a liquid crystal cell opposed to the coated film with the liquid crystal layer interposed therebetween, Wherein the liquid crystal aligning agent contains the following components (A), (B), and an organic solvent.
Component (A): at least one polymer selected from the group consisting of a polyimide precursor having a side chain that vertically aligns the liquid crystal, and an imide of the polyimide precursor.
(B): a polyimide precursor which is a reaction product of a tetracarboxylic acid dianhydride component and a diamine component including a tetracarboxylic acid dianhydride selected from the following formulas (1) and (1 '), and a polyimide precursor At least one kind of polymer selected from the group consisting of polyimide which is an imide of imide. However, the component (B) may be the same polymer as the component (A) when it has a side chain that vertically aligns the liquid crystal.
[Chemical Formula 1]

(j and k are each independently 0 or 1, and x and y are each independently a single bond, a carbonyl, an ester, a phenylene, a sulfonyl or an amide group) The method according to claim 1,
Wherein the liquid crystal layer in the liquid crystal display element is a liquid crystal layer containing a liquid crystal compound having an alkenyl liquid crystal. 3. The method according to claim 1 or 2,
Wherein the content ratio of the component (A) to the component (B) is in a mass ratio of the component (A): the component (B) = X: (10-X) (X = 1 to 9). 4. The method according to any one of claims 1 to 3,
Wherein the side chain for vertically orienting the liquid crystal in the component (A) is represented by the following formula (a).
(2)

(1, m and n each independently represents an integer of 0 or 1, and R ¹ represents an alkylene group having 2 to 6 carbon atoms, -O-, -COO-, -OCO-, -NHCO-, -CONH- , Or an alkylene-ether group having 1 to 3 carbon atoms; R ² , R ³ and R ⁴ each independently represent a phenylene group, a fluorine-containing phenylene group or a cycloalkylene group; R ⁵ represents a hydrogen atom, An alkyl group having 2 to 24 carbon atoms, a fluorine-containing alkyl group having 2 to 24 carbon atoms, a monovalent aromatic ring, a monovalent aliphatic ring, a monovalent heterocyclic ring, or a monovalent cyclic substituent composed thereof. A liquid crystal alignment film having a thickness of 5 to 300 nm obtained from the liquid crystal aligning agent according to any one of claims 1 to 4. A liquid crystal display element comprising the liquid crystal alignment film according to claim 5. A liquid crystal aligning agent containing a component (A), a component (B) and an organic solvent described below is coated on the conductive film of a pair of substrates each having a conductive film and then heated to form a first film A second step of constructing a liquid crystal cell by arranging a pair of substrates on which the coating film is formed so as to be opposed to each other with the liquid crystal layer being opposed to each other with the liquid crystal layer interposed therebetween and a third step of irradiating light to the liquid crystal cell Wherein the liquid crystal display element is a liquid crystal display element.
Component (A): at least one polymer selected from the group consisting of a polyimide precursor having side chains for vertically aligning liquid crystals, and polyimide as an imide of the polyimide precursor.
Component (B): a polyimide precursor which is a reaction product of a tetracarboxylic acid dianhydride component containing at least one tetracarboxylic acid dianhydride selected from the group consisting of the following formulas (1) and (1 ') and a diamine: , And a polyimide which is an imide of the polyimide precursor. However, the component (B) may be the same polymer as the component (A) when it has a side chain that vertically aligns the liquid crystal.
(3)

(Wherein j and k are each independently 0 or 1, and x and y are each independently a single bond, carbonyl, ester, phenylene, sulfonyl or amide group.) 8. The method of claim 7,
Wherein the liquid crystal layer is a liquid crystal layer containing a liquid crystal compound having an alkenyl-based liquid crystal. 9. The method according to claim 7 or 8,
Wherein the irradiation amount of ultraviolet rays is 1 to 50 J / cm &lt; 2 &gt;. 10. The method according to any one of claims 7 to 9,
Wherein the liquid crystal display element is a vertical alignment type display element.