JP5643985B2 - Diamine, liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element - Google Patents

Description

The present invention relates to a novel diamine, a liquid crystal aligning agent containing polyamic acid or a derivative thereof, and use thereof.

Liquid crystal display elements are used in various liquid crystal display devices such as monitors for notebook computers and desktop computers, video camera viewfinders, and projection displays. Recently, they have also been used as televisions. . Furthermore, it is also used as an optoelectronic-related element such as an optical printer head, an optical Fourier transform element, or a light valve.

A liquid crystal display element usually has 1) a pair of substrates arranged opposite to each other, 2) electrodes formed on one or both of the opposed surfaces of the pair of substrates, and 3) each of the pair of substrates. And a liquid crystal layer formed between the pair of substrates.

As a conventional liquid crystal display element, a display element using a nematic liquid crystal is mainstream, and 1) 90
TN (Twisted Nematic) type liquid crystal display element twisted twice, 2) STN (Super Twisted Nematic) type liquid crystal display element twisted more than 180 degrees, 3) So-called TFT (Thin Film Transistor) type liquid crystal display element using thin film transistors, etc. Has been put to practical use.
These liquid crystal display elements have a drawback that the viewing angle at which an image can be properly viewed is narrow, and when viewed from an oblique direction, luminance and contrast decrease and luminance inversion occurs in a halftone.

In recent years, regarding the problem of this viewing angle, 1) TN-TFT mode liquid crystal display element using an optical compensation film, 2) VA (Vertical Alignment) using vertical alignment and an optical compensation film
Mode liquid crystal display element, 3) MVA (Multi Domain) using both vertical alignment and protrusion structure technology
Vertical Alignment) mode LCD or 4) IPS (In-Plane)
Switching) mode liquid crystal display elements, etc. have been improved and put into practical use.

The development of the technology of the liquid crystal display element is achieved not only by simply improving these driving methods and element structures but also by improving the components used in the elements. Among the components used in liquid crystal display elements, the liquid crystal alignment film is one of important materials related to display quality, and the performance of the alignment film can be improved with the improvement in quality of the liquid crystal display element. It is becoming important.

The liquid crystal alignment film is prepared from a liquid crystal aligning agent. Currently, the liquid crystal aligning agent mainly used is a solution in which polyamic acid or soluble polyimide is dissolved in an organic solvent. After such a solution is applied to the substrate, the alignment film is formed by film formation by means such as heating. Liquid crystal aligning agents that use polymers other than polyamic acid are also being investigated, but heat resistance and chemical resistance (
(Liquid crystal resistance), applicability, liquid crystal orientation, electrical characteristics, optical characteristics, display characteristics, etc., have hardly been put into practical use.

Such an alignment film is required to have the following effects on the liquid crystal display element.
(1) Giving an appropriate pretilt angle to liquid crystal molecules. In addition, the pretilt angle is not easily affected by the indentation strength during rubbing or the temperature conditions during heating.
(2) No alignment defects of liquid crystal molecules due to uneven rubbing, scratches, or shaving of the alignment film.
(3) Give an appropriate voltage holding ratio (VHR) to the liquid crystal display element.
(4) A phenomenon called “burn-in” in which an image is displayed as an afterimage when an arbitrary image is displayed on the liquid crystal display element for a long time and then changed to another image, is less likely to occur.

Since the liquid crystal display element using the VA mode or the IPS mode has good viewing angle characteristics as described above, it is used in most liquid crystal TVs that have been developed in recent years. When comparing the performance of both modes, there are advantages and disadvantages due to the driving principle. For example, IP
The S mode has advantages such as particularly good viewing angle characteristics and a relatively fast response speed in halftone. However, the contrast is worse than the VA mode. In the IPS mode, black is displayed when no voltage is applied, and the fact that this state depends on the initial alignment state of the liquid crystal accompanying rubbing is one of the causes that deteriorate the contrast. That is, in the IPS alignment film, there is a strong demand for an alignment film that has high liquid crystal alignment properties and can display black more black (good black level). Patent document 1 is mentioned as an example of the prior art aiming at the solution of such a subject. However, although the technique of this document is characterized by using a diamine having a triple bond at the terminal, the effect has not been confirmed in an IPS mode liquid crystal display element.

JP 2009-300094 A

An object of the present invention is to develop a liquid crystal aligning agent for obtaining a liquid crystal aligning film having a high liquid crystal alignment property and a good black level.

The present inventors have found that a liquid crystal display element satisfying the above required characteristics can be obtained by using a liquid crystal aligning agent comprising a polyamic acid or a derivative thereof using a diamine having a specific structure as one of the raw materials. The present invention has been completed.

According to the present invention, a liquid crystal aligning agent with good alignment can be obtained. In particular, it is effective in improving the black level related to the IPS mode. Furthermore, according to the present invention, an effect of obtaining an alignment film having a small volume resistance value can also be achieved.

（式中、Ｒは窒素原子にメチレン基を介して末端に水酸基が結合されているアミド基であ
る。）
［２］ Ｒが（ａ）、（ｂ）、または（ｃ）で表される〔１〕記載のジアミン。

（式中、Ｒ⁰は水素またはメチル基である。）
[３] Ｒ ⁰ が水素である[２]に記載のジアミン。
[４] 式（Ｉ）中、２つのアミノ基がＲで表される置換基に対し、それぞれ３位、５位に
置換されている[１]〜[３]のいずれかに記載のジアミン。 The present invention has the following configuration.
[1] Diamine represented by general formula (I).

(In the formula, R is an amide group in which a hydroxyl group is bonded to the terminal of the nitrogen atom via a methylene group.)
[2] The diamine according to [1], wherein R is represented by (a), (b), or (c).

(In the formula, R ⁰ is hydrogen or a methyl group.)
[3] The diamine according to [2], wherein R ⁰ is hydrogen.
[4] The diamine according to any one of [1] to [3], wherein in the formula (I), two amino groups are substituted at the 3-position and the 5-position, respectively, with respect to the substituent represented by R.

式（ＤＡ−２０）において、Ｇ⁵は単結合、炭素数１〜１２のアルキレン、１，４−フェ
ニレン、または１，４−シクロヘキシレンであり；
Ｘ¹⁰は独立して単結合またはＣＨ₂である。；
そして、Ｇ⁶は独立してＣＨまたはＮであるが、Ｇ⁶がＮの場合はＧ⁵が単結合またはＣＨ₂
であることはなく、Ｘ¹⁰が単結合であることはない。

式（ＤＡ−２１）において、Ｒ¹⁴は独立して水素、メチル、エチル、またはフェニルであ
る。

式（ＤＡ−２２）において、環Ａ⁶はシクロヘキサン環またはベンゼン環である。

式（ＤＡ−２３）において、Ｇ⁷は単結合、炭素数１から１０のアルキレン、１，４−フ
ェニレン、Ｏ、ＣＯ、Ｓ、ＳＯ₂、Ｃ（ＣＨ₃）₂、またはＣ（ＣＦ₃）₂であり；そして、
環Ａ⁷は独立してシクロヘキサン環またはベンゼン環である。

式（ＤＡ−２４）において、Ｒ¹⁵は水素またはメチルである。

式（ＤＡ−２５）において、Ｘ¹⁰は単結合またはＣＨ₂であり；Ｘ¹¹は独立してＣＨ₂、Ｃ
Ｈ₂ＣＨ₂またはＣＨ＝ＣＨであり；そして、
ｖは１または２である。

式（ＤＡ−２６）において、Ｘ¹⁰は単結合またはＣＨ₂である。

式（ＤＡ−２７）において、Ｒ¹⁴は水素、メチル、エチル、またはフェニルであり；
環Ａ⁸はシクロヘキサン環、シクロヘキセン環またはベンゼン環であり；そして、Ｘ¹²は
単結合、ＣＨ₂またはＣＨ（ＣＨ₃）である。

式（ＤＡ−２８）において、ｗ２およびｗ３は０または１であるが、ｗ２＝１のときはｗ
３＝１である。

式（ＤＡ−３０）において、Ｘ¹³は独立して炭素数２〜６のアルキルであり；そして、
Ｐｈはフェニルを表す。

式（ＤＡ−３２）において、Ｘ¹⁴は独立して単結合またはＣＨ₂を表す。 [5] A polyamic acid obtained by reacting at least one diamine represented by the formula (I) according to any one of [1] to [4] with tetracarboxylic dianhydride and a derivative thereof.
[6] A mixture of at least one diamine represented by formula (I) according to any one of [1] to [4] and another diamine (D2) is reacted with tetracarboxylic dianhydride. The resulting polyamic acid and its derivatives.
[7] The polyamic acid according to [5] or [6], wherein the tetracarboxylic dianhydride is at least one selected from the group consisting of the following formulas (DA-20) to (DA-32) and Derivative.

In Formula (DA-20), G ⁵ is a single bond, alkylene having 1 to 12 carbons, 1,4-phenylene, or 1,4-cyclohexylene;
X ¹⁰ is independently a single bond or CH ₂ . ;
G ⁶ is independently CH or N. When G ⁶ is N, G ⁵ is a single bond or CH _2.
And X ¹⁰ is not a single bond.

In the formula (DA-21), R ¹⁴ is independently hydrogen, methyl, ethyl, or phenyl.

In formula (DA-22), ring A ⁶ is a cyclohexane ring or a benzene ring.

In the formula (DA-23), G ⁷ is a single bond, alkylene having 1 to 10 carbon atoms, 1,4-phenylene, O, CO, S, SO ₂ , C (CH ₃ ) ₂ , or C (CF ₃ ). ₂ ; and
Ring A ⁷ is independently a cyclohexane ring or a benzene ring.

In the formula (DA-24), R ¹⁵ is hydrogen or methyl.

In the formula (DA-25), X ¹⁰ is a single bond or CH ₂ ; X ¹¹ is independently CH ₂ , C ₂
H ₂ CH ₂ or CH═CH; and
v is 1 or 2.

In the formula (DA-26), X ¹⁰ is a single bond or CH ₂ .

In formula (DA-27), R ¹⁴ is hydrogen, methyl, ethyl, or phenyl;
Ring A ⁸ is a cyclohexane ring, a cyclohexene ring or a benzene ring; and X ¹² is a single bond, CH ₂ or CH (CH ₃ ).

In formula (DA-28), w2 and w3 are 0 or 1, but when w2 = 1, w2
3 = 1.

In formula (DA-30), X ¹³ is independently alkyl having 2 to 6 carbons; and
Ph represents phenyl.

In the formula (DA-32), X ¹⁴ independently represents a single bond or CH ₂ .

式（１−１）において、ｂは０または１であり；シクロヘキシレンにおける任意の水素は
メチルで置き換えられてもよく；
式（１−２）において、Ｗ¹は−ＣＨ₂−または−ＮＨ−であり：

ここに、Ｘ¹は単結合または炭素数１〜１０のアルキレンであり；このアルキレンの任意
の−ＣＨ₂−は−Ｏ−、−Ｓ−、−ＮＨ−、−Ｎ（ＣＨ₃）−、−Ｃ（ＣＨ₃）₂−、−Ｃ（
ＣＦ₃）₂−、−ＣＯ−、−ＳＯ₂−、１，３−フェニレン、１，４−フェニレンまたはピ
ペラジン−１，４−ジイルで置き換えられてもよく；

式（３）において、Ｘ²は単結合、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−または炭素数１〜６
のアルキレンであり；Ｒ¹は炭素数３〜３０のアルキル、または式（ａ）で表される基で
あり；
式（ａ）において、Ｘ³およびＸ⁴は独立して単結合または炭素数１〜４のアルキレンであ
り；環Ｂおよび環Ｃは独立して１，４−フェニレンまたは１，４−シクロヘキシレンであ
り；Ｒ²およびＲ³は独立してフッ素またはメチルであって、ｆおよびｇは独立して０、１
または２であり；ｃ、ｄおよびｅは独立して０または１であって、これらの合計は１〜３
であり；Ｒ⁴は炭素数１〜３０のアルキル、炭素数１〜３０のアルコキシ、炭素数２〜３
０のアルコキシアルキルまたはコレステリル基であり、これらのアルキル、アルコキシお
よびアルコキシアルキルにおいて、任意の水素はフッ素で置き換えられてもよく：

ここに、Ｘ⁵は独立して−Ｏ−または炭素数１〜６のアルキレンであり；ｊは独立して０
または１であり；Ｒ⁵は水素、炭素数２〜１２のアルキルまたは炭素数２〜１２のアルコ
キシであり；環Ｔは１，４−フェニレンまたは１，４−シクロヘキシレンであり；Ｘ⁶は
単結合または炭素数１〜３のアルキレンであり；ｈは０または１である。
[９]他のジアミン（Ｄ２）が下記の化合物の群から選ばれる少なくとも１つである[６]〜[７]のいずれかに記載のポリアミック酸およびその誘導体。

（式中、Ｒ¹¹は−ＣＨ₂−、−Ｏ−または炭素数１〜４の直鎖アルキレンであり、Ｒ¹²は
水素またはＣＨ₃であり、Ｒ¹³は炭素数２〜４の直鎖アルキレンであり、Ｒ¹⁴は炭素数１
〜８の直鎖アルキレンであり、Ｒ¹⁵は独立して−ＣＨ₂−、−（ＣＨ₂）₂−、または−Ｎ
Ｈ−であり、Ｒ¹⁶水素原子、または炭素数１〜１０の直鎖アルキレンであり、Ｒ¹⁷は水素
原子、または炭素数１〜１６の直鎖アルキレンであり、Ｒ¹⁸は独立して−ＣＨ₂−、−（
ＣＨ₂）₂−、または−Ｏ−である。） [8] The polyamic acid according to any one of [ 6 ] to [7] , wherein the other diamine (D2) is a diamine represented by the following formulas (1-1) to (4): Derivative.

In formula (1-1), b is 0 or 1; any hydrogen in cyclohexylene may be replaced with methyl;
In formula (1-2), W ¹ is —CH ₂ — or —NH—:

Here, X ¹ is a single bond or alkylene having 1 to 10 carbon atoms; any —CH ₂ — in the alkylene is —O—, —S—, —NH—, —N (CH ₃ ) —, — C (CH ₃ ) ₂ —, —C (
_{CF 3) 2 -, - CO} -, - SO 2 -, 1, 3- phenylene, 1, may be replaced by 4-phenylene or piperazine-1,4-diyl;

In Formula (3), X ² is a single bond, —O—, —COO—, —OCO—, or C 1-6.
R ¹ is alkyl having 3 to 30 carbon atoms or a group represented by formula (a);
In the formula (a), X ³ and X ⁴ are each independently a single bond or alkylene having 1 to 4 carbon atoms; Ring B and Ring C are each independently 1,4-phenylene or 1,4-cyclohexylene Yes; R ² and R ³ are independently fluorine or methyl, and f and g are independently 0, 1
Or c; d and e are independently 0 or 1, and their sum is 1 to 3;
R ⁴ is alkyl having 1 to 30 carbons, alkoxy having 1 to 30 carbons, or 2-3 carbons
Zero alkoxyalkyl or cholesteryl group, in which any hydrogen may be replaced by fluorine:

Wherein X ⁵ is independently —O— or alkylene having 1 to 6 carbon atoms; j is independently 0
Or it is 1; R ⁵ is hydrogen, alkyl or alkoxy having 2 to 12 carbon atoms having 2 to 12 carbon atoms; ring T is 1,4-phenylene or 1,4-cyclohexylene; X ⁶ represents a single A bond or alkylene having 1 to 3 carbon atoms; h is 0 or 1;
[9] The polyamic acid and the derivative thereof according to any one of [ 6 ] to [7] , wherein the other diamine (D2) is at least one selected from the group of the following compounds.

(In the formula, R ¹¹ is —CH ₂ —, —O— or straight chain alkylene having 1 to 4 carbon atoms, R ¹² is hydrogen or CH ₃ , and R ¹³ is straight chain alkylene having 2 to 4 carbon atoms. And R ¹⁴ has 1 carbon.
To 8 linear alkylene, and R ¹⁵ is independently —CH ₂ —, — (CH ₂ ) ₂ —, or —N.
H—, R ¹⁶ hydrogen atom, or straight-chain alkylene having 1 to 10 carbon atoms, R ¹⁷ is a hydrogen atom or straight-chain alkylene having 1 to 16 carbon atoms, and R ¹⁸ is independently —CH ₂ −, − (
CH ₂ ) ₂ — or —O—. )

[10] A composition comprising at least one polymer selected from the polyamic acid according to any one of [5] to [9] and a derivative thereof.
[11] At least one selected from the polyamic acid and derivatives thereof according to [5] to [9]
Liquid crystal aligning agent which consists of a composition containing two polymers.

（式中、ｎは１〜１０の整数である。） [12] The liquid crystal aligning agent according to [11], which contains an epoxy compound (E).
[13] The liquid crystal aligning agent according to [12], wherein the epoxy compound (E) is at least one selected from the group consisting of compounds represented by the following formulas (E1) to (E6).

(In the formula, n is an integer of 1 to 10.)

[14] The liquid crystal aligning agent according to [11], comprising an oxazoline compound (F).
[15] The liquid crystal aligning agent according to [14], wherein the oxazoline compound (F) is a compound represented by the following formula (F1).

[16] The liquid crystal aligning agent according to [11], comprising a bisallylnadiimide compound (G).
[17] The liquid crystal aligning agent according to [16], wherein the bisallylnadiimide compound (G) is at least one selected from the group consisting of compounds represented by the following formulas (G1) and (G2).

[18] The liquid crystal aligning agent according to [11], comprising one or more selected from the group consisting of the compounds represented by (E1) to (E6), (F1), (G1) and (G2).

[19] A liquid crystal alignment film formed from the liquid crystal aligning agent according to any one of [11] to [18].
[20] A liquid crystal display device comprising a liquid crystal alignment film comprising the liquid crystal alignment agent according to any one of [11] to [18].

（式中、Ｒは窒素原子にメチレン基を介して末端に水酸基が結合されているアミド基であ
る。） The diamine of the present invention can be represented by the following formula (I).

(In the formula, R is an amide group in which a hydroxyl group is bonded to the terminal of the nitrogen atom via a methylene group.)

（式中、Ｒ⁰は水素またはメチル基である。） In formula (I), a diamine in which R is represented by the following (a), (b), or (c) is more preferable.

(In the formula, R ⁰ is hydrogen or a methyl group.)

ジニトロ安息香酸クロライドをトリエチルアミンなどの塩基存在下、アミン化合物と反
応させることで、ジニトロベンズアミド化合物が得られる。このニトロ基を還元すること
で、本発明のジアミンが得られる。スキーム１中、Ｒ⁰は水素またはメチル基であり、Ｒ
’は下記で表される構造である。

A compound in which R represented by formula (I) is (a) or (b) can be synthesized by the method shown in Scheme 1.
Scheme 1.

A dinitrobenzamide compound is obtained by reacting dinitrobenzoic acid chloride with an amine compound in the presence of a base such as triethylamine. By reducing this nitro group, the diamine of the present invention is obtained. In Scheme 1, R ⁰ is hydrogen or a methyl group, R
'Is the structure represented below.

ジニトロ安息香酸クロライドをトリエチルアミンなどの塩基存在下、ジエタノールアミ
ンと反応させることでジニトロベンズアミド化合物が得られる。このニトロ基を還元する
ことで、本発明のジアミンが得られる。 A compound represented by formula (I) in which R is (c) can be synthesized by the method shown in Scheme 2.
Scheme 2.

A dinitrobenzamide compound is obtained by reacting dinitrobenzoic acid chloride with diethanolamine in the presence of a base such as triethylamine. By reducing this nitro group, the diamine of the present invention is obtained.

The liquid crystal aligning agent of the present invention is at least one selected from polyamic acid and derivatives thereof
A composition containing two polymers and a solvent. Polyamic acid derivatives include polyimide obtained by completely dehydrating and ring-closing the polyamic acid, partially imidized polyamic acid obtained by partially dehydrating and ring-closing the polyamic acid, polyamic acid ester, tetracarboxylic dianhydride And a polyamic acid-polyamide copolymer obtained by replacing a part of the polyamic acid with a dicarboxylic acid, and a polyamideimide obtained by subjecting a part or all of this polyamic acid-polyamide copolymer to a dehydration ring-closing reaction. Of these, polyimide and partially imidized polyamic acid are preferable, and polyimide is more preferable.

In the present invention, at least one selected from the group consisting of a polyamic acid obtained by reacting a mixture of a diamine represented by the formula (I) and another diamine (D2) with an acid dianhydride and a derivative thereof. Use polymer.

Specific examples of the diamine represented by the formula (I) used in the present invention include the following (I-1) to (
I-10), these may be used in combination, or only one may be used. Of these compounds, the compound (I-5) or (I-9) is particularly preferable.

When preparing a liquid crystal aligning agent using diamine (D2) other than this invention compound, in order to implement | achieve the effect of this invention more, the ratio in which this invention compound (I) is contained is with respect to the total usage-amount of diamine. Preferably it is 5-100 mol%, More preferably, it is 5-95 mol%, Most preferably, it is 20-80 mol%.

式（１−１）において、ｂは０または１であり、シクロヘキシレンにおける任意の水素は
メチルで置き換えられてもよい。
式（１−２）において、Ｗ¹は−ＣＨ₂−または−ＮＨ−である。 The diamine (D2) used in the present invention is selected without limitation from known diamines. Preferred diamines include diamine (1-1) to diamine (1-3), diamine (2), and diamine shown below. (3) and diamine (4) can be mentioned. It is preferable to use at least one diamine selected from the group of these diamines.

In formula (1-1), b is 0 or 1, and any hydrogen in cyclohexylene may be replaced with methyl.
In Formula (1-2), W ¹ is —CH ₂ — or —NH—.

Specific examples of these diamines (D2) are shown below. Among the following specific examples, the viewpoint of further improving the orientation of the liquid crystal, the viewpoint of improving the VHR of the liquid crystal display element, and the residual D in the alignment film
From any viewpoint of improving the relaxation rate of C, diamine (1-2-1) and diamine (1-3) are particularly preferable.

式（２）において、Ｘ¹は単結合または炭素数１〜１０のアルキレンであり、このアルキ
レンの任意の−ＣＨ₂−は−Ｏ−、−Ｓ−、−ＮＨ−、−Ｎ（ＣＨ₃）−、−Ｃ（ＣＨ₃）₂
−、−Ｃ（ＣＦ₃）₂−、−ＣＯ−、−ＳＯ₂−、１，３−フェニレン、１，４−フェニレ
ンまたはピペラジン−１，４−ジイルで置き換えられてもよい。Ｘ¹の好ましい例は炭素
数１〜１０のアルキレンであり、このときアルキレンの任意の−ＣＨ₂−は−Ｏ−、−Ｓ
−、−ＮＨ−、−Ｃ（ＣＨ₃）₂−、１，４−フェニレンまたはピペラジン−１，４−ジイ
ルで置き換えられてもよい。そして、アミノ基が結合するベンゼン環の任意の水素はメチ
ルで置き換えられてもよいが、メチルで置き換えられない方が好ましい。

In the formula (2), X ¹ is a single bond or alkylene having 1 to 10 carbon atoms, and any —CH ₂ — of the alkylene is —O—, —S—, —NH—, —N (CH ₃ ). _{-, - C (CH 3)} 2
_{-, - C (CF 3)} 2 -, - CO -, - SO 2 -, 1, 3- phenylene, 1, may be replaced by 4-phenylene or piperazine-1,4-diyl. A preferred example of X ¹ is alkylene having 1 to 10 carbon atoms, and in this case, any —CH ₂ — in the alkylene is —O— or —S.
-, - NH -, - C (CH 3) 2 -, 1, may be replaced by 4-phenylene or piperazine-1,4-diyl. Any hydrogen in the benzene ring to which the amino group is bonded may be replaced with methyl, but it is preferable that it is not replaced with methyl.

Specific examples of diamine (2) are shown below.

In Formula (3), X ² is a single bond, —O—, —COO—, —OCO—, or a carbon number of 1 to
6 alkylene, preferably a single bond, —O—, —COO—, or alkylene having 1 to 3 carbon atoms. R ¹ is an alkyl having 3 to 30 carbon atoms or a group represented by the formula (a), preferably an alkyl having 4 to 20 carbon atoms or a group represented by the formula (a).

In the formula (a), X ³ and X ⁴ are each independently a single bond or alkylene having 1 to 4 carbon atoms, preferably a single bond, —CH ₂ — or —CH ₂ CH ₂ —. Ring B and ring C are independently 1,4-phenylene or 1,4-cyclohexylene. R ² and R ³ are independently fluorine or methyl, and f and g are independently 0, 1 or 2, but it is preferred that both f and g are 0. c, d and e are independently 0 or 1,
The sum of these is 1-3. R ⁴ is alkyl having 1 to 30 carbons, alkoxy having 1 to 30 carbons or alkoxyalkyl having 2 to 30 carbons, and in these alkyls, alkoxys and alkoxyalkyls, any hydrogen may be replaced by fluorine. Good. R
Preferred examples of ⁴ are alkyl having 1 to 20 carbons, alkoxy having 1 to 20 carbons and alkoxyalkyl having 2 to 20 carbons, and hydrogen in these alkyls, alkoxys and alkoxyalkyls is replaced with fluorine. Absent.

Preferred examples of diamine (3) are shown below.

In formula (3-1) to formula (3-25), R ²⁰ is alkyl having 1 to ²⁰ carbons or alkoxy having 1 to 20 carbons, preferably alkyl having 5 to 16 carbons. R ²¹ is alkyl having 1 to 20 carbons or alkoxy having 1 to 20 carbons, preferably 3 carbons
-10 alkyl. R ²² is an alkyl or cholesteryl group having 4 to 20 carbon atoms, preferably an alkyl or cholesteryl group having 6 to 16 carbon atoms. R ²³ is 4 to 4 carbon atoms
20 alkyl, preferably alkyl having 6 to 16 carbon atoms. R ²⁴ has 3 to 3 carbon atoms
20 alkyl or C3-20 alkoxy, preferably C5-12 alkyl.

In the formula (4), X ⁵ is independently -O- or an alkylene having 1 to 6 carbon atoms, preferably together -O -, - CH ₂ - or -CH ₂ CH ₂ -. j is independently 0 or 1
It is. R ⁵ is hydrogen, alkyl having 1 to 20 carbons or alkoxy having 1 to 20 carbons, preferably hydrogen, alkyl having 1 to 12 carbons or alkoxy having 1 to 12 carbons, more preferably carbon number. 4-7 alkyl. Ring T is 1,4-phenylene or 1,4-cyclohexylene. X ⁶ is a single bond or alkylene having 1 to 3 carbon atoms. H is 0 or 1. In addition, the bonding position of the amino group to the benzene ring is X
It is preferably para-position to ⁵ .

Preferred examples of diamine (4) are shown below.

In the formula (4-1) to the formula (4-16), R ²⁶ is hydrogen, alkyl having 1 to 12 carbons or alkoxy having 1 to 12 carbons, preferably alkyl having 4 to 7 carbons.

Among the specific examples of the diamine (D2), the following diamine (1-2-1), diamine (1-3), diamine (2-1) to diamine (2-3), diamine (2-7) ), Diamine (2-10) to diamine (2-27), diamine (2-29), diamine (2-37) to
Diamine (2-41), Diamine (2-43) to Diamine (2-47), Diamine (2-
51), diamine (3-1) to diamine (3-12-1), and diamine (4-1) to
Diamine (4-12) is more preferred.

Here, R ²⁰ is alkyl having 5 to 16 carbons, and R ²¹ is alkyl having 3 to 10 carbons.

ここに、Ｒ²⁶は炭素数４〜７のアルキルである。

Here, R ²⁶ is alkyl having 4 to 7 carbon atoms.

Among the more preferable examples of the diamine (D2), when importance is attached to further improving the orientation of the liquid crystal, the diamine (1-2-1), diamine (1-3), diamine (
2-7), diamine (2-10) to diamine (2-12), diamine (2-16) to diamine (2-19), diamine (2-21) to diamine (2-27), diamine (2 -37
) To diamine (2-41), diamine (2-43) to diamine (2-47), diamine (
2-51), diamine (3-1) to diamine (3-11), and diamine (4-1) to
Diamine (4-12) is more preferred, diamine (1-2-1), diamine (1-3)
, Diamine (2-7), diamine (2-10) to diamine (2-12), diamine (2-
26), diamine (2-44), diamine (2-45), and diamine (3-1) to diamine (3-6) are particularly preferable.

Among the more preferable examples of the diamine (D2), when emphasizing the application of high VHR to the liquid crystal alignment film, the diamine (1-2-1), diamine (1-3), diamine (2 -1) to diamine (2-3), diamine (2-26), diamine (2-29), diamine (2-37), diamine (2-43) to diamine (2-47), diamine (3- 1)
To diamine (3-11) and diamine (4-1) to diamine (4-12) are more preferable, and diamine (2-1) to diamine (2-3), diamine (2-26), diamine (
2-29), diamine (2-44), and diamine (3-1) to diamine (3-6) are particularly preferable.

Among the more preferable examples of the diamine (D2), when importance is attached to reducing the volume resistance value of the liquid crystal alignment film, the diamine (1-2-1), diamine (1-3), diamine ( 2-1) to diamine (2-3), diamine (2-13) to diamine (2-15), diamine (2-20) to diamine (2-26), diamine (2-29), and diamine (
2-39) to diamine (2-41) are more preferable, and diamine (2-1) to diamine (
2-3), diamine (2-13) to diamine (2-15), diamine (2-26) and diamine (2-29) are particularly preferred.

By the way, diamine can be divided into two types depending on the difference in structure. That is, 2
When a skeleton connecting two amino groups is viewed as a main chain, the group is branched from the main chain, that is, a diamine having a side chain group and a diamine having no side chain group. By reacting a diamine having a side chain group with tetracarboxylic dianhydride, a polyamic acid having a large number of side chain groups with respect to the main chain of the polymer is obtained. When a polyamic acid having a side chain group with respect to such a polymer main chain is used, the liquid crystal alignment film formed from the liquid crystal alignment agent containing this polymer can increase the pretilt angle in the liquid crystal display element. . That is, this side chain group is a group having an effect of increasing the pretilt angle. The side chain group having such an effect needs to be a group having 3 or more carbon atoms. Specific examples include alkyl having 3 or more carbon atoms, alkoxy having 3 or more carbon atoms, and alkoxyalkyl having 3 or more carbon atoms. The group which has can be mentioned. A group having one or more rings, wherein the terminal ring is any one of alkyl having 1 or more carbon atoms, alkoxy having 1 or more carbon atoms and alkoxyalkyl having 2 or more carbon atoms as a substituent.
The group having one has an effect as a side chain group. When a diamine having such a side chain group is a side chain diamine, and a diamine having no such side chain group is a non-side chain diamine,
Said diamine (3) and diamine (4) are side chain type diamine, and diamine (1-1
) To diamine (1-3) and diamine (2) are non-side chain diamines.

Then, by properly using the side chain diamine and the non-side chain diamine, it is possible to cope with the pretilt angle required for each of various display elements. That is, in the vertical electric field method represented by the TN method and the VA method, a relatively large pretilt angle is required, and therefore, a side chain type diamine is mainly used. At this time, in order to further control the pretilt angle, a non-side chain diamine may be used in combination. What is necessary is just to determine the compounding ratio of non-side chain type diamine and side chain type diamine according to the magnitude | size of the target pretilt angle. Of course, it is possible to use only a side chain type diamine by appropriately selecting a side chain group. In the lateral electric field method, since the pretilt angle is small and high liquid crystal orientation is required, at least one of non-side chain diamines may be used.

In the present invention, in order to express a pretilt angle of 2 degrees or more in particular, the use ratio of the side chain diamine is preferably 5 to 70 mol%, and preferably 10 to 50 mol% in the total amount of diamine. Is more preferable.

The tetracarboxylic dianhydride used for synthesizing the polyamic acid of the present invention (hereinafter sometimes simply referred to as “acid anhydride”) should be selected from known acid anhydrides without limitation. However, preferred examples of the acid anhydride (A-1) to acid anhydride (A-48) are shown below. It is preferable to use at least one of these acid anhydrides.

Among the above acid anhydrides, acid anhydride (A-1) to acid anhydride (A-4), acid anhydride (A-1
1), acid anhydride (A-12), acid anhydride (A-14), acid anhydride (A-15), acid anhydride (A-16), acid anhydride (A-20) to acid anhydride Product (A-23), acid anhydride (A-30) to
Acid anhydride (A-32), acid anhydride (A-34), acid anhydride (A-39), acid anhydride (A-
41) to acid anhydride (A-43), and acid anhydride (A-45) to acid anhydride (A-48) are more preferable.

When importance is attached to further improving the orientation of the liquid crystal, among the above acid anhydrides, acid anhydride (A-1), acid anhydride (A-2), acid anhydride (A-12) , Acid anhydride (A-14)
, Acid anhydride (A-15), acid anhydride (A-16), acid anhydride (A-20), acid anhydride (A
-22), acid anhydride (A-23), acid anhydride (A-30), acid anhydride (A-32), acid anhydride (A-39) , acid anhydride (A-42) and ( A-47) is more preferable, and acid anhydride (A-1), acid anhydride (A-12), acid anhydride (A-14), acid anhydride (A-20) and (A-47) are preferred. Particularly preferred.

When importance is attached to improving the VHR of the liquid crystal display element, among the acid anhydrides,
Acid anhydride (A-16), acid anhydride (A-20), acid anhydride (A-21), acid anhydride (A-
22), acid anhydride (A-23), acid anhydride (A-30), acid anhydride (A-31), acid anhydride (A-32), acid anhydride (A-34), acid anhydride Product (A-41), acid anhydride (A-42)
More preferred are alicyclic compounds of acid anhydride (A-43), acid anhydride (A-45), acid anhydride (A-46) and acid anhydride (A-48). -16), acid anhydride (A-2
2), acid anhydride (A-23), acid anhydride (A-41), acid anhydride (A-46) and acid anhydride (A-48) are particularly preferred.

The polyamic acid used for the liquid crystal aligning agent of this invention is obtained by making the mixture of said acid anhydride and diamine react in a solvent. In this synthesis reaction, no special conditions other than the selection of the raw materials are required, and the conditions for normal polyamic acid synthesis can be applied as they are. The solvent to be used will be described later.

ここに、Ｒ³⁰およびＲ³¹は独立して炭素数１〜３のアルキルまたはフェニルであり、Ｒ³²
は炭素数１〜６のアルキレン、フェニレンまたはアルキル置換されたフェニレンであり、
ｙは１〜１０の整数である。 In the liquid crystal aligning agent of the present invention, at least one siloxane-based diamine may be used in combination in order to prevent abrasion due to rubbing. As a preferable example of this siloxane diamine, the formula (15
The diamine represented by this can be mentioned.

Here, R ³⁰ and R ³¹ are independently alkyl or phenyl having 1 to 3 carbon atoms, and R ³²
Is alkylene having 1 to 6 carbon atoms, phenylene or alkyl-substituted phenylene,
y is an integer of 1-10.

（式（１５−２）のポリマーの分子量は８５０〜３０００である。） Specific examples of the diamine (15) include the following compounds or polymers.

(The molecular weight of the polymer of the formula (15-2) is 850 to 3000.)

When these siloxane-based diamines are used, the addition amount is preferably 0.5 to 30 mol% with respect to the total amount of diamine used as a raw material for the purpose of expressing the above effects and preventing other properties from being deteriorated. 10 mol% is more preferable.

The alignment agent of the present invention may further contain an organosilicon compound from the viewpoint of adjusting the adhesion of the alignment film to the glass substrate. Examples of organosilicon compounds are aminopropyltrimethoxysilane, aminopropyltriethoxysilane, vinyltrimethoxysilane, N- (2-
Aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltri Methoxysilane, 3
Silane coupling agents such as glycidoxypropylmethyldimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and silicone oils such as dimethylpolysiloxane, polydimethylsiloxane, and polydiphenylsiloxane.

The addition ratio of the organosilicon compound to the alignment agent is not particularly limited as long as the effect of the present invention is obtained. However, when a large amount of the organosilicon compound is added, liquid crystal alignment failure may occur when the alignment film is formed. Therefore, when the organosilicon compound is added, the concentration thereof is preferably in the range of 0.01 to 5% by weight, particularly preferably 0.1 to 3% by weight, based on the weight of the polymer contained in the aligning agent. Range.

The aligning agent of the present invention may further contain a compound having two or more functional groups that react with the carboxyl group of polyamic acid or its derivative, so-called cross-linking agent, from the viewpoint of preventing deterioration of characteristics over time and deterioration due to the environment. Good. As an example of such a crosslinking agent, Japanese Patent No. 30496
Examples thereof include polyfunctional epoxies and isocyanate materials as described in Japanese Patent No. 99, Japanese Patent Laid-Open No. 2005-275360, Japanese Patent Laid-Open No. 10-212484, and the like.

One of the causes of deterioration of electrical characteristics of liquid crystal display elements over time is the influence of carboxyl groups remaining in the alignment film, and other members for forming liquid crystal display elements on the alignment film, such as liquid crystal compounds and sealants The interaction that occurs due to adsorption is considered. In the liquid crystal aligning agent of the present invention,
When a polyfunctional epoxy compound as represented by the above (E1) to (E5) is contained, in the step of forming the alignment film (that is, the heating step), the residual carboxylic acid of polyimide reacts with the epoxy compound, A chemically more stable group, specifically an ester group, is formed, and the interaction with other members can be reduced. Therefore, even if the liquid crystal display element is used for a long time, the initial electrical characteristics can be maintained. In addition, by using a polyfunctional epoxy compound, there is also an effect of cross-linking polyimides forming the liquid crystal aligning agent, the initial alignment state can be maintained, and the electrical characteristics of the liquid crystal display element can be stabilized for a long period of time. Degradation can be prevented. In addition, when an epoxy compound containing silicon as represented by (E6) is contained, it not only acts on the residual carboxylic acid as described above, but also improves the adhesion of the alignment film to the glass substrate. it can. As a result, it is possible to provide resistance such as preventing the alignment film from being peeled off from the glass substrate during the rubbing process of the alignment film performed in the manufacturing process of the liquid crystal display element.

The alignment agent of the present invention may further contain an oxazoline compound and / or an oxazine compound from the viewpoint of stabilizing the electrical characteristics of the liquid crystal display element for a long period of time. The oxazoline compound is a compound having an oxazoline structure in the molecule. By adding the oxazoline compound, the remaining carboxyl group in the alignment film reacts with the step of forming the alignment film (heating step) to form a more stable group, specifically an amide ester group. Thus, the electrical characteristics can be stabilized for a long time. The term “stable group” as used herein does not refer to the stability of the organic group itself, but is used to mean a group that has little action to adsorb other substances such as liquid crystal compounds in a display element. . Further, by using a compound having two or more oxazoline structures, it can act as a cross-linking agent and can maintain an initial alignment state for a long time. As a result, the electrical characteristics of the liquid crystal display element can be stabilized for a long period of time, and the display quality can be prevented from deteriorating. Specific examples of the oxazoline compound include 2,2′-bis (2
-Oxazoline), 1,2,4-tris- (2-oxazolinyl-2) -benzene, 4-
Furan-2-ylmethylene-2-phenyl-4H-oxazol-5-one, 1,4-bis (4,5-dihydro-2-oxazolyl) benzene, 1,3-bis (4,5-dihydro-2- Oxazolyl) benzene, 2,3-bis (4-isopropenyl-2-oxazolin-2-yl) butane, 2,2'-bis-4-benzyl-2-oxazoline, 2,6-bis (isopropyl-2- Oxazolin-2-yl) pyridine, 2,2′-isopropylidenebis (4-tert-butyl-2-oxazoline), 2,2′-isopropylidenebis (
4-phenyl-2-oxazoline), 2,2′-methylenebis (4-tert-butyl-
2-oxazoline), and 2,2′-methylenebis (4-phenyl-2-oxazoline). In addition to these, polymers and oligomers having oxazolyl such as Epocross (trade name, manufactured by Nippon Shokubai Co., Ltd.) can also be exemplified. Among these oxazoline compounds, in particular, 1,3-bis (4,5-dihydro-2-oxazolyl) benzene (compound (
Using a compound represented by) in F1), without reducing the inherent characteristics of the liquid crystal alignment film, it is possible to prevent the aging of the liquid crystal display device. The content of the oxazoline compound is 0.1 to 50% by weight based on the total amount of the polymer components. The content of the oxazoline compound is preferably 1 to 40% by weight, and more preferably 1 to 20% by weight.

An oxazine compound is a compound having an oxazine structure in the molecule. Various structures of oxazine compounds are known. Although the structure of the oxazine compound used by this invention is not specifically limited, The structure of the oxazine which has aromatic groups containing condensed polycyclic aromatic groups, such as a benzoxazine and a naphthoxazine, is illustrated. Examples of the oxazine compound include compounds described in International Publication No. 2004/009708 pamphlet, JP-A-11-12258, JP-A-2004-352670, and the like. The content of the oxazine compound is 0.1 to 50% by weight based on the total amount of the polymer components. The content of the oxazine compound is preferably 1 to 40% by weight, and more preferably 1 to 20% by weight.

Further, a crosslinking agent that reacts with the crosslinking agent itself to form a polymer having a network structure and improves the film strength of polyamic acid or polyimide can be used for the same purpose as described above. Examples of such a crosslinking agent include JP-A-10-310608 and JP-A-2004-341030.
And polyfunctional vinyl ethers, maleimides, and bisallylnadiimide derivatives represented by the above compounds (G1) and (G2). When these cross-linking agents are used, the preferred ratio is 5 to 100 based on the total amount of polymer components.
% By weight, more preferably 10 to 50% by weight.

In the liquid crystal aligning agent of the present invention, it is preferable to use at least one polyamic acid, but the polyamic acid and other polyamic acid produced without using the diamine (I) of the present invention may be used in combination. . The mixing ratio when combining other polyamic acids is 10 to 95% by weight of the polyamic acid of the present invention based on the total amount of the polymer, 5 to 90% by weight of the other polyamic acid, and the ratio of the polyamic acid of the present invention is Even if there are few, sufficient effect can be acquired. In the liquid crystal aligning agent of this invention, polymers other than the polyamic acid obtained by reaction with an acid anhydride and diamine, for example, polyester, an epoxy resin, etc. can be used together. However, the ratio when such other polymer is used in combination is preferably 30% by weight or less based on the total weight of the polymer.

The aligning agent of the present invention is a solution in which polyamic acid is dissolved in a solvent. This solvent can be appropriately selected from known solvents used in the production and use of polyamic acid according to the purpose of use. Examples of these solvents are as follows.

Examples of aprotic polar organic solvents include N-methyl-2-pyrrolidone (NMP), dimethylimidazolidinone, N-methylcaprolactam, N-methylpropionamide, N
, N-dimethylacetamide, dimethyl sulfoxide, N, N-dimethylformamide (
DMF), N, N-diethylformamide, N, N-diethylacetamide (DMAc)
And lactones such as γ-butyrolactone (GBL).

Preferred examples of solvents other than those described above for the purpose of improving coatability include alkyl lactate, 3-methyl-3-methoxybutanol, tetralin, isophorone, ethylene glycol monoalkyl ether (eg, ethylene glycol monoalkyl). Butyl ether (BCS)
), Diethylene glycol monoalkyl ether (eg diethylene glycol monoethyl ether), ethylene glycol monophenyl ether, triethylene glycol monoalkyl ether, propylene glycol monoalkyl ether (eg propylene glycol monobutyl ether), dialkyl malonate (eg malonic acid) Diethyl), dipropylene glycol monoalkyl ether (eg, dipropylene glycol monomethyl ether),
And ester compounds of these glycol monoethers. Of these, N
MP, dimethylimidazolidinone, GBL, BCS, diethylene glycol monoethyl ether, propylene glycol monobutyl ether and dipropylene glycol monomethyl ether are particularly preferred.

The aligning agent of the present invention can further contain various additives as required. For example, a surfactant suitable for the purpose may be contained when further improvement in coating properties is desired, and an appropriate amount of antistatic agent may be contained when further improvement in antistatic properties is required.

The concentration of the polymer in the aligning agent of the present invention is preferably 0.1 to 40% by weight.
More preferably, it is 10 weight%. When it is necessary to adjust the film thickness when applying this aligning agent to the substrate, the concentration of the contained polymer can be adjusted by diluting with a solvent in advance.

The viscosity of the liquid crystal aligning agent of the present invention is determined by the coating method, the concentration of polyamic acid and its derivative,
The preferred range varies depending on the type of polyamic acid and its derivative used and the type and proportion of the solvent. For example, in the case of application by a printing press, it is 5 to 100 mPa · s (more preferably 10 to 80 mPa · s). If it is less than 5 mPa · s, it is difficult to obtain a sufficient film thickness, and if it exceeds 100 mPa · s, printing unevenness may increase. In the case of spin coating, 5 to 200 mPa · s (more preferably 10 to 100 mPa · s) is suitable. In the case of coating using an inkjet coating apparatus, 5 to 50 mPa · s (more preferably 5 to 20 mPa · s) is suitable. The viscosity of the liquid crystal aligning agent is measured by a rotational viscosity measuring method, and is measured using, for example, a rotational viscometer (TVE-20L type manufactured by Toki Sangyo) (measurement temperature: 25).
° C).

In the alignment film of the present invention, the alignment agent is applied to the substrate by the method described below, and the solvent is removed by heating (pre-baking) at a relatively low temperature if necessary; In order to increase the acid imidization ratio and to exhibit the original properties of the alignment film, it can be obtained by heating (main firing) at a relatively high temperature. The film thus obtained may be rubbed as necessary.

As a method for applying the liquid crystal aligning agent, a spinner method, a printing method, a dipping method, a dropping method, an ink jet method and the like are generally known. These methods are also applicable in the present invention.

The liquid crystal display element according to the present invention includes a pair of substrates disposed opposite to each other, electrodes formed on one or both of the opposed surfaces of the pair of substrates, and the pair of substrates opposed to each other. A liquid crystal display element having a liquid crystal alignment film of the present invention formed on a surface on which the liquid crystal is formed and a liquid crystal layer formed between the pair of substrates.

The electrode is not particularly limited as long as it is an electrode formed on one surface of the substrate. Examples of such electrodes include ITO and metal vapor deposition films. Further, the electrode may be formed on the entire surface of one surface of the substrate, or may be formed in a desired shape that is patterned, for example. Examples of the desired shape of the electrode include a comb shape or a zigzag structure. The electrode may be formed on one of the pair of substrates, or may be formed on both substrates. The form of electrode formation varies depending on the type of liquid crystal display element. For example, in the case of an IPS liquid crystal display element, an electrode is disposed on one of the pair of substrates, and in the case of other liquid crystal display elements, the electrodes of the pair of substrates are arranged. Electrodes are arranged on both sides. The liquid crystal alignment film is formed on the substrate or electrode.

The liquid crystal layer is formed in such a manner that the liquid crystal composition is sandwiched between the pair of substrates facing each other on which the liquid crystal alignment film is formed. In the formation of the liquid crystal layer, a spacer such as fine particles or a resin sheet that is interposed between the pair of substrates to form an appropriate interval can be used as necessary. The liquid crystal composition is not particularly limited, and a known liquid crystal composition can be used.

The alignment film of the present invention can improve the characteristics of all known liquid crystal compositions when a liquid crystal display element is formed as the liquid crystal alignment film. The alignment film of the present invention produced by the above method is particularly effective in improving alignment defects of large screen displays that are difficult to be rubbed. Such a large screen display is driven and controlled by TFTs. Also such T
The liquid crystal composition used in the FT type liquid crystal display element is disclosed in Japanese Patent No. 3086228 and Japanese Patent No. 26.
No. 35435, JP-A-5-501735, and JP-A-9-255756. Therefore, the alignment film of the present invention is preferably used in combination with the liquid crystal composition described therein.

The liquid crystal display element of the present invention is excellent in orientation, for example, when it is used for IPS, it exhibits a high black level value. The black level value can be measured as follows. That is, a cell assembled with the rubbing direction antiparallel is placed on the stage of the microscope, and the polarizer and the analyzer are rotated so as to obtain the minimum luminance. Light of a certain brightness is applied from behind the cell, the light transmitted through the cell is detected using a photomultiplier tube attached to a polarizing microscope, and the amount of transmitted light is converted into a voltage and measured ( Polarization microscope magnification 100 ×; eyepiece 10 × objective 10 ×). The smaller the voltage value obtained, the better the black level. In the present application, it is actually preferably 1500 μV or less, and more preferably 900 μV or less.

The alignment film of the present invention can give a particularly good black level and high electrical characteristics to the liquid crystal display element.
Such excellent characteristics are manifested by using the diamine (1) of the present invention. At this time, the substitutable site other than the OH and NH ₂ groups of the diamine (1) of the present invention may be substituted with an arbitrary group that does not cause deterioration of properties.

The liquid crystal display element of the present invention is also excellent in electrical characteristics relating to the reliability of the liquid crystal display element. Such electrical characteristics include voltage holding ratio and ion density. The voltage holding ratio (VHR) is a ratio at which the voltage applied to the liquid crystal display element during the frame period is held in the liquid crystal display element, and indicates display characteristics of the liquid crystal display element. The liquid crystal display element of the present invention uses a rectangular wave of 5 V and a frequency of 30 Hz, and the voltage holding ratio measured at a temperature condition of 60 ° C. is 97.0%.
From the viewpoint of preventing display defects, it is preferable that the voltage holding ratio measured using a rectangular wave of 5 V and a frequency of 0.3 Hz with a temperature of 60 ° C. is 85.0% or more.

The ion density is a transient current other than that caused by driving of the liquid crystal generated when a voltage is applied to the liquid crystal display element, and indicates the magnitude of the concentration of ionic impurities contained in the liquid crystal in the liquid crystal display element.
The liquid crystal display element of the present invention preferably has an ion density of 300 pC or less from the viewpoint of preventing image sticking of the liquid crystal display element.

Hereinafter, the present invention will be described with reference to examples and comparative examples.
The evaluation method of the liquid crystal display element in an Example is as follows.

<Pretilt angle measurement>
Measured according to the crystal rotation method.

<Voltage holding ratio>
In accordance with the method described in “Mizushima et al., Proceedings of the 14th Liquid Crystal Panel Discussion Meeting p78 (1988)”, 6
At 0 ° C., a rectangular wave having a peak value of ± 5 V was applied to the cell. The value of the voltage holding ratio is an index indicating how much the applied voltage is held after the frame period, and this value is 100%.
Then, it indicates that all charges are held.

<Measurement of ion content in liquid crystal (ion density)>
According to the method described in Applied Physics, Vol. 65, No. 10, 1065 (1996), measurement was performed using a liquid crystal property measuring system 6254 type manufactured by Toyo Technica. Using a triangular wave with a frequency of 0.01 Hz, measurement was performed at a voltage range of ± 10 V and a temperature of 60 ° C. (electrode area is 1 cm ² ). If the ion density is high, defects such as seizure due to ionic impurities are likely to occur. That is, the ion density is a physical property value that serves as an index for predicting the occurrence of image sticking.

^<1 H-NMR>
Measurement was performed using DRX-500 manufactured by Bruker BioSpin. All samples are 1wt
Measured with% deuterated chloroform.

<Weight average molecular weight (Mw)>
The weight average molecular weight (Mw) of the polyamic acid in the liquid crystal aligning agent was 0.6% by weight phosphoric acid-containing DMF as an eluent, using a GF7MHQ column manufactured by Shodex Co., Ltd., at a column temperature of 50 ° C. Measured by chromatography (GPC) method,
It was determined by converting to polystyrene.

<Viscosity>
It measured at 25 degreeC using the viscometer (the Toki Sangyo company make, TV-22).

Example 1 Synthesis of Compound (I-5) <First Step; Synthesis of Amide>
To a 200 mL three-necked flask equipped with a stirrer, a thermometer, a nitrogen introduction tube, and a dropping funnel, 10.0 g of commercially available 2-amino-2-hydroxymethyl-1,3-propanediol (
82.6 mmol) and 10.0 g (99.1 mmol) of triethylamine.
, N-dimethylformamide was dissolved in 50 mL. The solution was cooled to 5 ° C., and 15.2 g (66.0 mmol) of commercially available 3,5-dinitrobenzoyl chloride was slowly added thereto. Next, the reaction solution was heated to 80 ° C. and further stirred for 12 hours. After allowing to cool, the solvent was distilled off under reduced pressure to obtain crude crystals. The obtained crude crystals were recrystallized from ethanol to give 3,5-dinitro-N-
((Trihydroxymethyl) methyl) benzamide was obtained. Yield 17.7 g, 85% yield
.

<Second stage; reduction of nitro group>
In an autoclave reaction tube, 17.0 g (53.9 mmol) of 3,5-dinitro-N-((trihydroxymethyl) methyl) benzamide obtained above and 5% palladium /
Carbon powder 1.7g was put and ethanol 500mL was added. The system was placed in a hydrogen atmosphere and stirred at room temperature for 24 hours at a hydrogen pressure of 0.5 mPa. Remove the palladium / carbon powder in the reaction solution,
The solvent was distilled off under reduced pressure to obtain crude crystals. The obtained crude crystals are recrystallized from ethanol to give 3,5
-Diamino-N-((trihydroxymethyl) methyl) benzamide was obtained. Yield 12.
5 g, 91% yield.
¹ H-NMR (ppm); 6.89 (s, —NHCO—, 1H), 6.13 (d, arm
. H, 2H), 5.91 (t, arm.H, 1H), 4.91-4.93 (br.s,-
_{OH, -NH 2, 7H),} 3.58-3.60 (d, -CH 2 -, 6H).

Example 2 Synthesis of Compound (1-9) <First Step; Synthesis of Amide>
In a 200 mL three-necked flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a dropping funnel, 10.0 g (95.1 mmol) of commercially available diethanolamine and 11.5 g (114.1 mmol) of triethylamine were added, and N, N- Dissolved in 100 mL of dimethylformamide. The solution is cooled to 5 ° C. whereupon commercially available 3,5-dinitrobenzoyl chloride 21
. 9 g (95.1 mmol) was added slowly. Next, the reaction solution was heated to 80 ° C. and further stirred for 12 hours. After allowing to cool, the solvent was distilled off under reduced pressure to obtain crude crystals. The obtained crude crystals were recrystallized from ethanol to obtain N, N-bis (2-hydroxyethyl) -3,5-dinitrobenzamide. Yield 25.0 g, 88% yield.

<Second stage; reduction of nitro group>
In the reaction tube for autoclave, the N, N-bis (2-hydroxyethyl) -3 obtained previously is used.
, 5-dinitrobenzamide 20.0 g (66.8 mmol) and 5% palladium / carbon powder 2.0 g were added, and 500 mL of ethanol was added. The system was placed in a hydrogen atmosphere and stirred at room temperature for 24 hours at a hydrogen pressure of 0.5 mPa. The palladium / carbon powder in the reaction solution was removed, and the solvent was distilled off under reduced pressure to obtain crude crystals. The obtained crude crystals were recrystallized from ethanol to give N, N-
Bis (2-hydroxyethyl) -3,5-diaminobenzamide was obtained. Yield 14.4 g
Yield 90%.

[Example 3]
< Synthesis of polyamic acid>
Compound (I) synthesized in accordance with Example 1 in a three-necked flask equipped with a stirrer and a thermometer
-5) 2.2641 g and 4,4′-diaminodiphenylmethane (compound (2-1))
0.4396 g was added, and 60 g of N-methyl-2-pyrrolidone (NMP) was added and dissolved therein. The solution was cooled to 5 ° C. and there cyclobutane tetracarboxylic dianhydride (MMDA (A-16)) 1.0871g and pyromellitic dianhydride (PMDA (A-1)) 1.2091g was added, 5 g of NMP Was added. The reaction was warmed to room temperature and stirred for 12 hours. Thereto was added 30 g of ethylene glycol monobutyl ether (BC) to obtain a solution having a polyamic acid concentration of 5% by weight. The 25 ° C. viscosity of the solution was 35 mPa · sec. This solution was named Varnish A. The weight average molecular weight of the polyamic acid in this varnish was 42,000.

[Examples 4 to 17]
A varnish having a polyamic acid concentration of 5% by weight and a viscosity at 25 ° C. of 35 mPa · sec was obtained in the same manner as in Example 3 except that diamine and dianhydride were changed as described in Table 1. The measured values of the monomer composition and the weight average molecular weight of the polymer contained in the prepared varnish are shown in Table 1 including Example 3 (mol% in parentheses).

[Example 18]
<Black level measurement cell production>
Weigh 1.0 g of varnish A into a sample bottle, add NMP / BC = 1/1 (weight ratio), and add 1
. 67 g. A solution having a polyamic acid concentration of about 3% by weight was dropped onto a transparent glass substrate and applied by a spinner method (2,000 rpm, 15 seconds). After coating, the substrate is 80 ° C
The mixture was heated for 3 minutes to evaporate the solvent, and then heat-treated in an oven at 230 ° C. for 20 minutes. A polyimide film having a thickness of about 70 nm formed by this heat treatment was rubbed (indentation; 0.3 mm, stage feed speed: 60 m / sec, rotation speed: 1000 rpm, rubbing cloth; YA-18-R (rayon)) . The alignment film was subjected to ultrasonic cleaning for 5 minutes in ultrapure water and then dried in an oven at 120 ° C. for 30 minutes. Two glass substrates are placed facing each other so that the surface on which the alignment film is formed is inward and the rubbing direction is antiparallel, and then sealed with an epoxy curing agent containing a 25 μm gap agent, and anti-parallel with a gap of 25 μm. A cell was produced. The following liquid crystal composition A was injected into this cell, and the inlet was sealed with a photocurable sealant. Next, a heat treatment was performed at 110 ° C. for 30 minutes to manufacture a liquid crystal display element. When the black level was measured using the obtained cell, the measured voltage value was 1,070 μV.

<Liquid crystal composition A>

[Examples 19 to 32]
A black level measuring cell was prepared in accordance with the method described in Example 18 except that varnish A was replaced with varnish B to varnish O. However, for the cell produced using varnish H, the polyimide film was not rubbed and the liquid crystal composition B was injected. The measurement result of the black level is shown in Table 2 together with the result of Example 18.

<Liquid crystal composition B>

作製したセルの全てで良好な黒レベルが観測された。

Good black levels were observed in all of the fabricated cells.

[Example 33]
<Preparation of cell for measuring pretilt angle and electrical characteristics>
Weigh 1.0 g of varnish A into a sample bottle, add NMP / BC = 1/1 (weight ratio), and add 1
. 67 g. A solution having a polyamic acid concentration of about 3% by weight was dropped on a transparent glass substrate and applied by a spinner method (2,000 rpm, 15 seconds). After coating, the substrate was heated at 80 ° C. for 3 minutes to evaporate the solvent, and then heat-treated in an oven at 230 ° C. for 20 minutes. A polyimide film having a thickness of about 70 nm formed by this heat treatment was rubbed (indentation; 0.3 mm, stage feed speed: 60 m / s, rotation speed: 1000 rpm, rubbing cloth; YA-1
8-R (rayon)). The alignment film was ultrasonically cleaned in ultrapure water for 5 minutes, and then dried in an oven at 120 ° C. for 30 minutes. A 7 μm gap agent was spread on one alignment film. This and another substrate were placed facing each other so that the rubbing direction was antiparallel with the alignment film surface inside, and then sealed with an epoxy curing agent to produce an anti-parallel cell with a gap of 7 μm.
Liquid crystal composition A was injected into this cell, and the injection port was sealed with a photocurable sealant. Then 110
A heat treatment was performed at 30 ° C. for 30 minutes to produce a liquid crystal display element. The voltage holding ratio of this cell is 98.
It was 5% (30 Hz) and 90.5% (0.3 Hz), the pretilt angle was 1.2 °, and the ion density was 85 pC.

[Examples 34 to 47]
A cell for measuring electrical characteristics was produced in accordance with the method described in Example 33 except that varnish A was replaced with varnish B to varnish O. However, for the cell produced using varnish H, the polyimide film was not rubbed and the liquid crystal composition B was injected. The measurement results of the electrical characteristics and the pretilt angle are shown in Table 3 together with the result of Example 33.

作製したセルの全てで良好なＶＨＲおよびイオン密度が観測された。

Good VHR and ion density were observed in all of the fabricated cells.

[Examples 48 to 62]
<Confirmation of effect of epoxy compound additive>
Varnish A to O was weighed 1.0 g in each sample bottle, and NMP / BC = 1/1 (weight ratio) was added to make 1.67 g. To this, 0.01 g of any one of the epoxy additives (E1) to (E5) was added and sufficiently stirred. According to the method described in Example 17, a black level measurement cell and an electrical property measurement cell were produced. However, for the cell produced using varnish H, the polyimide film was not rubbed and the liquid crystal composition B was injected. Using the prepared cell, black level measurement, VHR measurement (30 Hz and 0.3 Hz), ion density measurement and pretilt angle measurement were performed. The measurement results are shown in Table 4.

エポキシ化合物を添加することにより、ＶＨＲおよびイオン密度が低下することも無く
、また、プレチルト角の変動も無く、かつ、黒レベルがさらに向上することが確認された
。

By adding an epoxy compound, it was confirmed that the VHR and the ion density were not lowered, the pretilt angle was not changed, and the black level was further improved.

[Examples 63 to 77]
<Confirmation of effect of oxazoline compound additive>
Varnish A to O was weighed 1.0 g in each sample bottle, and NMP / BC = 1/1 (weight ratio) was added to make 1.67 g. 0.01 g of oxazoline additive (F1) was added thereto and stirred sufficiently. According to the method described in Example 17, a black level measurement cell and an electrical property measurement cell were produced. However, for the cell produced using varnish H, the polyimide film was not rubbed and the liquid crystal composition B was injected. Using the prepared cell, black level measurement, VHR measurement (30 Hz and 0.3 Hz), ion density measurement and pretilt angle measurement were performed. The measurement results are shown in Table 5.

オキサゾリン化合物を添加することにより、ＶＨＲおよびイオン密度が低下することも
無く、また、プレチルト角の変動も無く、かつ、黒レベルがさらに向上することが確認さ
れた。

By adding the oxazoline compound, it was confirmed that VHR and ion density were not lowered, the pretilt angle was not changed, and the black level was further improved.

＜第１段階；アミドの合成＞
攪拌装置、温度計、窒素導入管および滴下漏斗を装着した２００ｍＬ３つ口フラスコに
、市販の３−アミノ−３−エチル−ｎ−ペンタン１０．０ｇ（８６．８ｍｍｏｌ）および
トリエチルアミン１３．２ｇ（１３０．２ｍｍｏｌ）をいれ、Ｎ，Ｎ−ジメチルホルムア
ミド５０ｍＬに溶解した。溶液を５℃に冷却し、そこに市販の３，５−ジニトロベンゾイ
ルクロリド１８．０ｇ（７８．１ｍｍｏｌ）をゆっくり加えた。次いで反応液を８０℃ま
で昇温させ１２時間攪拌した。放冷後、溶媒を減圧留去して粗結晶を得た。得られた粗結
晶をトルエンから再結晶して、３，５−ジニトロ−Ｎ−（（トリエチル）メチル）ベンズ
アミドを得た。収量１９．６ｇ、収率８１％。 [Comparative Example 1] Synthesis of Compound C1

<First stage; synthesis of amide>
In a 200 mL three-necked flask equipped with a stirrer, a thermometer, a nitrogen inlet tube and a dropping funnel, 10.0 g (86.8 mmol) of commercially available 3-amino-3-ethyl-n-pentane and 13.2 g (130. 2 mmol) and dissolved in 50 mL of N, N-dimethylformamide. The solution was cooled to 5 ° C., and 18.0 g (78.1 mmol) of commercially available 3,5-dinitrobenzoyl chloride was slowly added thereto. Subsequently, the reaction liquid was heated up to 80 degreeC and stirred for 12 hours. After allowing to cool, the solvent was distilled off under reduced pressure to obtain crude crystals. The obtained crude crystals were recrystallized from toluene to obtain 3,5-dinitro-N-((triethyl) methyl) benzamide. Yield 19.6 g, 81% yield.

<Second stage; reduction of nitro group>
In an autoclave reaction tube, 19.0 g (61.4 mmol) of 3,5-dinitro-N-((triethyl) methyl) benzamide obtained earlier and 5% palladium / carbon powder were added, and 500 mL of ethanol was added. The inside of the system was set to a hydrogen atmosphere, and the mixture was stirred at a hydrogen pressure of 0.5 mPa and room temperature for 24 hours. The palladium / carbon powder in the reaction solution was removed, and the solvent was distilled off under reduced pressure to obtain crude crystals. The obtained crude crystals were recrystallized from ethanol to give 3,5-diamino-N-
((Triethyl) methyl) benzamide was obtained. Yield 13.6 g, 89% yield.
¹ H-NMR (ppm); 7.42 (s, —NHCO—, 1H), 6.45 (d, arm
. H, 2H), 5.90 (t , arm.H, 1H), 4.78 (br.s, -NH 2, 4
H), 1.41-1.45 (q, -CH 2 -, 6H), 1.04 (t, -CH 3, 9H).

[Comparative Examples 2 to 4]
<Preparation of polyamic acid>
In accordance with the method described in Example 2, varnish X to varnish Z having a polyamic acid concentration of 5% by weight and a viscosity of 35 mPa · s were obtained. The prepared varnish is shown in Table 6 (mol% in parentheses).

ジアミンＣ１を原料の一つとして用いた配向剤からなるセルは、黒表示特性が十分でな
いことがわかった。 [Comparative Examples 5 to 7]
<Black level measurement and electrical characteristic measurement>
In accordance with the method described in Example 17, a black level measurement cell and an electrical property measurement cell were prepared and measured. The measurement results are shown in Table 7.

It was found that the cell composed of the aligning agent using diamine C1 as one of the raw materials has insufficient black display characteristics.

種々の化合物を添加しても、黒表示の改善は見られなかった。また、一部のセルではプ
レチルト角の変動が確認された。 [Comparative Examples 8 to 10]
<Confirmation of effect of additive>
1.0 g of varnish Z obtained in Comparative Example 7 was weighed into a sample bottle, and NMP / BC = 1/1
(Weight ratio) was added to obtain 1.67 g. To this, 0.01 g of either one of an epoxy compound or an oxazoline compound was added and stirred sufficiently. According to the method described in Example 17, a black level measurement cell and an electrical property measurement cell were prepared and measured. The added compounds and measurement results are shown in Table 8.

Even when various compounds were added, the black display was not improved. In addition, fluctuations in the pretilt angle were confirmed in some cells.

Claims (19)

In general formula (I), R is a diamine represented by the following (a), (b), or (c).

(In the formula, R ⁰ is hydrogen or a methyl group.) The diamine according to claim 1, wherein R ⁰ is hydrogen. The diamine according to claim 1 or 2, wherein two amino groups in the formula (I) are substituted at the 3-position and the 5-position, respectively, with respect to the substituent represented by R. A polyamic acid , a polyimide or a partially imidized polyamic acid obtained by reacting at least one diamine represented by the formula (I) according to any one of claims 1 to 3 with a tetracarboxylic dianhydride . A polyamic acid obtained by reacting a mixture of at least one diamine represented by formula (I) according to any one of claims 1 to 3 with another diamine (D2) with tetracarboxylic dianhydride , Polyimide or partially imidized polyamic acid. The polyamic acid , polyimide or partial imide according to claim 4 or 5, wherein the tetracarboxylic dianhydride is one or more selected from the group consisting of the following formulas (DA-20) to (DA-32). Polyamic acid.

In Formula (DA-20), G ⁵ is a single bond, alkylene having 1 to 12 carbons, 1,4-phenylene, or 1,4-cyclohexylene;
X ¹⁰ is independently a single bond or CH ₂ . ;
G ⁶ is independently CH or N. However, when G ⁶ is N, G ⁵ is not a single bond or CH ₂ , and X ¹⁰ is not a single bond.

In formula (DA-21), R ¹⁴ is independently hydrogen, methyl, ethyl, or phenyl.

In formula (DA-22), ring A ⁶ is a cyclohexane ring or a benzene ring.

In Formula (DA-23), G ⁷ is a single bond, alkylene having 1 to 10 carbons, 1,4-phenylene, O, CO, S, SO ₂ , C (CH ₃ ) ₂ , or C (CF ₃ ). it is _2; and ring a ⁷ is independently a cyclohexane ring or a benzene ring.

In the formula (DA-24), R ¹⁵ is hydrogen or methyl.

In formula (DA-25), X ¹⁰ is a single bond or CH ₂ ; X ¹¹ is independently CH ₂ , CH ₂ CH ₂ or CH═CH; and
v is 1 or 2.

In the formula (DA-26), X ¹⁰ is a single bond or CH ₂ .

In formula (DA-27), R ¹⁴ is hydrogen, methyl, ethyl, or phenyl;
Ring A ⁸ is a cyclohexane ring, a cyclohexene ring or a benzene ring; and X ¹² is a single bond, CH ₂ or CH (CH ₃ ).

In Formula (DA-28), W2 and W3 are 0 or 1, but when W2 = 1, W3 = 1.

In formula (DA-30), X ¹³ is independently alkyl having 2 to 6 carbons; and
Ph represents phenyl.

In the formula (DA-32), X ¹⁴ independently represents a single bond or CH ₂ . The other diamine (D2) is a diamine represented by the following formulas (1-1) to (4), the polyamic acid , polyimide or partially imidized polyamic acid according to claim 5 or 6 .

In formula (1-1), b is 0 or 1; any hydrogen in cyclohexylene may be replaced with methyl;
In formula (1-2), W ¹ is —CH ₂ — or —NH—:

Here, X ¹ is a single bond or alkylene having 1 to 10 carbon atoms; any —CH ₂ — in the alkylene is —O—, —S—, —NH—, —N (CH ₃ ) —, — C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, —CO—, —SO ₂ —, 1,3-phenylene, 1,4-phenylene or piperazine-1,4-diyl Often;

In Formula (3), X ² is a single bond, —O—, —COO—, —OCO—, or alkylene having 1 to 6 carbons; R ¹ is alkyl having 3 to 30 carbons, or Formula (a) A group represented by:
In the formula (a), X ³ and X ⁴ are each independently a single bond or alkylene having 1 to 4 carbon atoms; Ring B and Ring C are independently 1,4-phenylene or 1,4-cyclohexylene R ² and R ³ are independently fluorine or methyl, f and g are independently 0, 1 or 2, c, d and e are independently 0 or 1, R ⁴ is alkyl having 1 to 30 carbons, alkoxy having 1 to 30 carbons, alkoxyalkyl having 2 to 30 carbons or a cholesteryl group, and these alkyls, alkoxys and alkoxyalkyls Any hydrogen may be replaced by fluorine:

Wherein X ⁵ is independently —O— or alkylene having 1 to 6 carbons; j is independently 0 or 1; R ⁵ is hydrogen, alkyl having 2 to 12 carbons or 2 carbons. ˜12 alkoxy; ring T is 1,4-phenylene or 1,4-cyclohexylene; X ⁶ is a single bond or alkylene having 1 to 3 carbon atoms; h is 0 or 1; The polyamic acid , polyimide or partially imidized polyamic acid according to claim 5 or 6, wherein the other diamine (D2) is at least one selected from the following group of compounds .

(In the formula, R ¹¹ is —CH ₂ —, —O— or a linear alkylene having 1 to 4 carbon atoms, R ¹² is hydrogen or CH ₃ , and R ¹³ is a linear alkylene having 2 to 4 carbon atoms. R ¹⁴ is a linear alkylene having 1 to 8 carbon atoms, R ¹⁵ is independently —CH ₂ —, — (CH ₂ ) ₂ —, or —NH—, R ¹⁶ is a hydrogen atom, Or a linear alkylene having 1 to 10 carbon atoms, R ¹⁷ is a hydrogen atom or a linear alkylene having 1 to 16 carbon atoms, and R ¹⁸ is independently —CH ₂ —, — (CH ₂ ) ₂ —. Or -O-.) The composition containing the at least 1 polymer chosen from the polyamic acid in any one of Claims 4-8 , a polyimide, or a partially imidized polyamic acid . The liquid crystal aligning agent which consists of a composition containing the at least 1 polymer chosen from the polyamic acid in any one of Claims 4-8 , a polyimide, or a partially imidized polyamic acid . The liquid crystal aligning agent of Claim 10 containing an epoxy compound (E). The liquid crystal aligning agent according to claim 11, wherein the epoxy compound (E) is at least one selected from the group consisting of compounds represented by the following formulas (E1) to (E6).

(In the formula, n is an integer of 1 to 10.) The liquid crystal aligning agent of Claim 10 containing an oxazoline compound (F). The liquid crystal aligning agent according to claim 13, wherein the oxazoline compound (F) is a compound represented by the following formula (F1).

The liquid crystal aligning agent of Claim 10 containing a bisallyl nadiimide compound (G). The liquid crystal aligning agent according to claim 15, wherein the bisallylnadiimide compound (G) is at least one selected from the group consisting of compounds represented by the following formulas (G1) and (G2).

The liquid crystal aligning agent of Claim 10 containing 1 or more types chosen from the group which consists of a compound represented by said (E1)-(E6), (F1), (G1), and (G2). The liquid crystal aligning film formed from the liquid crystal aligning agent in any one of Claims 10-17. The liquid crystal display element which comprises the liquid crystal aligning film which consists of a liquid crystal aligning agent in any one of Claims 10-17.