JP5359643B2 - Diamine, liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element - Google Patents

Abstract

The present invention is provided to develop a polyamic acid capable of achieving many characteristics (high voltage holding capacity, little remained DC (direct current), high liquid crystal alignability, high rubbing resistance, etc.) required by a liquid crystal (LC) alignment layer. The invention is achieved through a diamine shown by formula (1). In formula (1), Y represents a single bond or a 1-9 C linear alkylene group, and any -CH2- in the alkylene group may be replaced by -O-, -N(CH3)-, 1,4-phenylene, 1,4-cyclohexylene or piperazine-1,4-diyl; n is 0 or 1; and one hydrogen of a benzene ring that the amino group is bonded to may be replaced by -OH. However, when Y is an alkylene and n is 0, -CH2- that the amino group is bonded to is not replaced by -O- or -N(CH3)-.

Description

  The present invention relates to a novel diamine and a polyamic acid obtained using the same, and further relates to its use. The term “liquid crystal aligning agent” in the present invention means a polymer-containing composition used for forming a liquid crystal aligning film.

  Liquid crystal display elements are used in various display devices such as mobile phone displays, laptop and desktop PC monitors, video camera viewfinders, and projection displays. It has become. Furthermore, they are also used as optoelectronic-related elements such as optical printer heads, optical Fourier transform elements, and light valves. As a conventional liquid crystal display element, a display element using a nematic liquid crystal is mainly used. 1) TN (Twisted Nematic) type liquid crystal display element twisted by 90 degrees, 2) STN (Super Twisted Nematic) twisted by 180 degrees or more. 3) so-called TFT (Thin Film Transistor) type liquid crystal display elements using thin film transistors have been put into practical use.

  However, these liquid crystal display elements have a drawback that a viewing angle at which an image can be properly viewed is narrow, and when viewed from an oblique direction, luminance and contrast are lowered and luminance is inverted in a halftone. In recent years, the problem of this viewing angle is as follows: 1) TN-TFT type liquid crystal display element using optical compensation film, 2) VA (vertical alignment) type liquid crystal display element using vertical alignment and optical compensation film, 3) vertical MVA (Multi Domain Vertical Alignment) type liquid crystal display element using both alignment and protrusion structure technology, or 4) In-plane switching (IPS) type liquid crystal display element of horizontal electric field type, 5) ECB (Electrically Controlled Birefringence) type Liquid crystal display elements, 6) Improved by techniques such as optically compensated bend (Optically Compensated Bend or Optically Self-Compensated Birefringence: OCB) type liquid crystal display elements, and these elements have been put into practical use.

  The development of the technology of the liquid crystal display element has been achieved not only by improving the drive system and the element structure, but also by improving the components used for the display element. Among the constituent members used in display elements, the liquid crystal alignment film is one of the important elements related to the display quality of the liquid crystal display element, and the role of the liquid crystal alignment film is increasing as the quality of the display element increases. It has become important year after year.

  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 applying such a solution to the substrate, a polyimide-based alignment film is formed by film formation by means such as heating. Various liquid crystal aligning agents other than polyamic acid are also being studied, but they are almost practical in terms of heat resistance, chemical resistance (liquid crystal resistance), coating properties, liquid crystal alignment properties, electrical properties, optical properties, display properties, etc. It has not been converted.

  In order to improve the display quality of a liquid crystal display element (LCD), a characteristic required for a liquid crystal alignment film is required to have a high voltage holding ratio (VHR). In an active matrix LCD, for example, if the voltage holding ratio is low, the voltage applied to the liquid crystal during the frame period is lowered, resulting in a change in luminance, and normal gradation does not occur. In particular, LCDs have recently been used for television applications, and it has become important that the deterioration of VHR with time is small. In order to produce a large-screen LCD with a clear display, the backlight has a high luminance, and an alignment film that does not deteriorate VHR due to light or heat has been demanded.

  Next, an important characteristic required for the alignment film is a small residual charge (DC). Residual DC is a charge that accumulates between the electrodes as the LCD is driven. Due to this phenomenon, an extra voltage is applied to the electrodes. For example, the display image remains without disappearing even after the voltage is turned off. Will occur. As one method for reducing the residual DC, it has recently been reported that a liquid crystal alignment film having a small residual DC can be produced by using a diamine having a nitrogen atom (Patent Documents 1, 2, and 3).

International Publication No. 2004-053583 Pamphlet International Publication No. 2004-021076 Pamphlet JP-A-10-104633

  However, as the performance of liquid crystal display devices increases, an alignment film that can further reduce residual DC is required, and it is difficult to completely satisfy the required characteristics only with the conventionally proposed technology. It has become to.

  The object of the present invention is to develop a polyamic acid that can achieve many of the characteristics required for liquid crystal alignment films (high voltage holding ratio, small residual DC, high liquid crystal alignment, high rubbing resistance, etc.) It is to be.

  The present inventors have intensively studied to solve the above problems, and by introducing a 1-phenylindole structure into a diamine that is a raw material of polyamic acid, the liquid crystal display element having an alignment film made of this polymer has high performance. It has been found that the residual DC can be reduced while maintaining the voltage holding ratio. Furthermore, the present invention was completed by finding that the diamine of the present invention and the polyamic acid or polyimide using the diamine of the present invention have high solubility in commonly used solvents.

ここに、Ｙは単結合または炭素数１〜９の直鎖アルキレンであり；このアルキレンの任意の−ＣＨ_２−は−Ｏ−、−Ｎ（ＣＨ_３）−、１，４−フェニレン、１，４−シクロへキシ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；ｎは０または１であり；そして、アミノ基が結合しているベンゼン環の１つの水素は−ＯＨで置き換えられてもよい。但し、Ｙがアルキレンであってｎが０であるとき、アミノ基が結合する−ＣＨ_２−が−Ｏ−または−Ｎ（ＣＨ_３）−で置き換えられることはない。 The diamine of the present invention is shown in the following item [1].
[1] Diamine represented by formula (1):

Here, Y is a single bond or a linear alkylene having 1 to 9 carbon atoms; any —CH ₂ — in the alkylene is —O—, —N (CH ₃ ) —, 1,4-phenylene, 1, May be replaced by 4-cyclohexylene or piperazine-1,4-diyl; n is 0 or 1; and one hydrogen of the benzene ring to which the amino group is bonded is replaced by —OH. Also good. However, when Y is alkylene and n is 0, —CH ₂ — to which the amino group is bonded is not replaced by —O— or —N (CH ₃ ) —.

  The diamine of the present invention can be easily synthesized without using a special reaction apparatus, and the liquid crystal aligning agent of the present invention is soluble in a solvent usually used in the art and does not cause precipitation during storage. According to the present invention, a liquid crystal display element having a high voltage holding ratio and a small residual DC can be provided.

First, terms used in the present invention will be described. The diamine represented by formula (1) may be referred to as diamine (1). Diamines represented by other formulas may be indicated by similar abbreviations. For compounds other than diamines, for example, tetracarboxylic dianhydride represented by the formula (A) may be abbreviated as acid anhydride (A). The term “arbitrary” used in describing a chemical formula means “can be freely selected not only by position but also by number”. For example, the expression “any A may be replaced with B, C, D, or E” means that one A may be replaced with B, C, D, or E, and In addition to the meaning that any may be replaced by any one of B, C, D and E, A replaced by B, A replaced by C, A replaced by D, and E replaced It also means that at least two of A may be mixed. When any —CH ₂ — may be replaced by —O—, such a replacement that results in the linking group —O—O— is not included.

  A substituent in which the bonding position with the carbon constituting the ring is not clear means that the bonding position is free as long as there is no chemical problem. When the same symbol is used in more than one formula, it means that the groups have the same scope of definition but does not mean that all formulas must be the same group at the same time. The same group may be used in a plurality of formulas, or different groups may be used for each formula.

The present invention comprises the above item [1] and the following items [2] to [11].
[2] The diamine according to item [1], wherein the benzene ring to which the amino group is bonded is a benzene ring not having —OH as a substituent.

[3] The diamine according to item [1], wherein the benzene ring to which the amino group is bonded is a benzene ring having a substituent —OH at one of the ortho positions with respect to the amino group.

[4] The diamine according to item [1], wherein Y is a single bond or 1,4-phenylene, and n is 0.

[5] Y is a single bond, or a linear alkylene having 1 to 9 carbon atoms in which arbitrary —CH ₂ — may be replaced by —O— or —N (CH ₃ ) —; The diamine according to item [1].

[6] A diamine mixture comprising at least one diamine according to item [1] or at least one diamine according to item [1] and at least one other diamine, and at least one tetracarboxylic acid anhydride, A polyamic acid obtained by reacting.

[7] The polyamic acid according to item [6], wherein the at least one tetracarboxylic acid anhydride is a tetracarboxylic acid anhydride selected from compounds represented by formulas (A1) to (A63).

[8] A polyimide obtained by dehydrating and ring-closing the polyamic acid according to the item [6].

[9] A solution containing at least one polymer selected from the group consisting of the polyamic acid according to the item [6] and the polyimide according to the item [8].

[10] A liquid crystal aligning agent comprising the polymer solution according to the item [9].

[11] A liquid crystal display device having a liquid crystal alignment film obtained from the liquid crystal aligning agent according to the item [10].

The diamine of the present invention is represented by the formula (1).

In the formula (1), Y is a single bond or a linear alkylene having 1 to 9 carbon atoms. And any —CH ₂ — in the alkylene may be replaced by —O—, —N (CH ₃ ) —, 1,4-phenylene, 1,4-cyclohexylene or piperazine-1,4-diyl. Good. Preferred examples of Y include a single bond, 1,4-phenylene, piperazine-1,4-diyl, and any carbon atom in which any —CH ₂ — may be replaced by —O— or —N (CH ₃ ) —. ~ 9 linear alkylene. More preferred examples of Y are 1,4-phenylene and straight-chain alkylene having 1 to 9 carbon atoms in which arbitrary —CH ₂ — may be replaced by —O— or —N (CH ₃ ) —. n is 0 or 1. However, when Y is alkylene as described above and n is 0, —CH ₂ — to which the amino group is bonded is not replaced by —O— or —N (CH ₃ ) —. And one hydrogen of the benzene ring to which the amino group is bonded may be replaced with -OH. When this benzene ring has one substituent —OH, the position is ortho-position or meta-position with respect to the bonding position of the amino group, and ortho-position is preferred.

  The polyamic acid obtained by reacting the diamine (1) with tetracarboxylic dianhydride has high solubility in a solvent, and can prevent polymer precipitation during storage in a refrigerator or the like. Depending on the raw material composition other than the diamine (1), when it is expected that the polyamic acid has poor solubility, it is possible to improve the solubility by using an asymmetric diamine (1) where n is 0. This is preferable. Moreover, also when using a polyimide with lower solubility than a polyamic acid for an aligning agent, it is preferable to use the diamine (1) whose n in Formula (1) is 0.

In order to obtain an alignment film having a larger alignment regulating force, Y is preferably a linear alkylene having 1 to 9 carbon atoms, more preferably a linear alkylene having 2 to 9 carbon atoms. The alkylene in this case is an alkylene in which —CH ₂ — is not replaced by another group.

  The alignment film obtained from the polyamic acid using the diamine of the present invention as a raw material has an extremely large effect of reducing residual DC. Therefore, by using other known diamines having a particularly large alignment regulating force as shown below in combination with the diamine (1), an alignment film having a large alignment regulating force for liquid crystals and a low residual DC can be obtained. it can.

Any —CH ₂ — in the linear alkylene of Y can be replaced with —O— or N (CH ₃ ) — in order to adjust the electrical properties of the alignment film to the desired values. At that time, in view of easy availability of raw materials, those in which —CH ₂ — adjacent to the indole ring is replaced by —O— or N (CH ₃ ) — are preferred, and —O— and N are considered from the stability of the compound. It is preferred that (CH ₃ ) — are not adjacent.

Specific examples of diamine (1) are shown below.

Ｓｃｈｅｍｅ１中、（Ｓ１−１）で表される市販の５−アミノインドールまたは６−アミノインドールを水素化ナトリウムなどの塩基存在下、４−フルオロニトロベンゼンと反応させ（Ｓ１−２）で表される化合物を得る。次いで、（Ｓ１−２）で表される化合物を水素接触還元でニトロ基を還元することにより、式（１）で表されるジアミンを合成できる。 Diamine (1) where Y is a single bond and n is 0 can be synthesized by the route shown below.

A compound represented by (S1-2) by reacting commercially available 5-aminoindole or 6-aminoindole represented by (S1-1) with 4-fluoronitrobenzene in the presence of a base such as sodium hydride in Scheme 1 Get. Subsequently, the diamine represented by the formula (1) can be synthesized by reducing the nitro group by hydrogen reduction of the compound represented by (S1-2).

上記Ｓｃｈｅｍｅ２中、（Ｓ２−１）で表されるジアミン（ここでＹは単結合または炭素数１〜９の直鎖アルキレンである）とトリエタノールアンモニウムクロライドとをＴｅｔｒａｈｅｄｒｏｎ Ｌｅｔｔｅｒｓ ４１（１１），１８１１−１８１４（２０００）に記載の方法に従い反応させて（Ｓ２−２）で表される化合物を得る。次いで、水素化ナトリウムなどの塩基存在下、４−フルオロニトロベンゼンと反応させ（Ｓ２−３）で表される化合物を得る。次いで（Ｓ２−３）で表される化合物を水素接触還元でニトロ基を還元することで、式（１）で表されるジアミンが合成できる。 A compound in which Y is a linear alkylene group having 1 to 9 carbon atoms and n is 1 can be synthesized by the route shown below.

In the above Scheme 2, a diamine represented by (S2-1) (wherein Y is a single bond or a linear alkylene having 1 to 9 carbon atoms) and triethanolammonium chloride are added to Tetrahedron Letters 41 (11), 1811- The compound represented by (S2-2) is obtained by reacting according to the method described in 1814 (2000). Next, it is reacted with 4-fluoronitrobenzene in the presence of a base such as sodium hydride to obtain a compound represented by (S2-3). Subsequently, the diamine represented by the formula (1) can be synthesized by reducing the nitro group by hydrogen catalytic reduction of the compound represented by (S2-3).

上記Ｓｃｈｅｍｅ３中、（Ｓ３−１）で表される化合物とアミノアセチライド（ここでＹ’は単結合または炭素数１〜７の直鎖アルキレンである）とをTetrahedron Letters 34(40), 6403-6406(1993)に記載の方法に従い反応させて、（Ｓ３−２）で表される化合物を得る。次いで、水素化ナトリウムなどの塩基存在下、４−フルオロニトロベンゼンと反応させ（Ｓ３−３）で表される化合物を得る。次いで（Ｓ３−３）で表される化合物を水素接触還元でニトロ基を還元することで、式（１）で表されるジアミンが合成できる。 A compound in which Y is a linear alkylene having 2 to 9 carbon atoms and n is 0 can be synthesized by the route shown below.

In the above Scheme 3, a compound represented by (S3-1) and an aminoacetylide (where Y ′ is a single bond or a linear alkylene having 1 to 7 carbon atoms) are converted into Tetrahedron Letters 34 (40), 6403- Reaction is carried out according to the method described in 6406 (1993) to obtain a compound represented by (S3-2). Next, it is reacted with 4-fluoronitrobenzene in the presence of a base such as sodium hydride to obtain a compound represented by (S3-3). Subsequently, the diamine represented by the formula (1) can be synthesized by reducing the nitro group by hydrogen catalytic reduction of the compound represented by (S3-3).

上記Ｓｃｈｅｍｅ４中、（Ｓ４−１）で表される市販の５−（アミノメチル）インドールまたは６−（アミノメチル）インドールと水素化ナトリウムなどの塩基存在下、４−フルオロニトロベンゼンとを反応させ（Ｓ４−２）で表される化合物を得る。次いで（Ｓ４−２）で表される化合物を水素接触還元でニトロ基を還元することで、式（１）で表されるジアミンが合成できる。 A compound in which Y is methylene having 1 carbon atom and n is 0 can be synthesized by the following route.

In the above Scheme 4, commercially available 5- (aminomethyl) indole represented by (S4-1) or 6- (aminomethyl) indole is reacted with 4-fluoronitrobenzene in the presence of a base such as sodium hydride (S4 -2) is obtained. Subsequently, the diamine represented by the formula (1) can be synthesized by reducing the nitro group by hydrogen catalytic reduction of the compound represented by (S4-2).

上記Ｓｃｈｅｍｅ５において、（Ｓ５−１）で表される市販の５−ブロモインドールまたは６−ブロモインドールと、市販の４−アミノフェニルボロン酸とをパラジウム触媒を用いたカップリング反応により（Ｓ５−２）で表される化合物を得る。次いで、水素化ナトリウムなどの塩基存在下、４−フルオロニトロベンゼンと反応させ（Ｓ５−３）で表される化合物を得る。次いで（Ｓ５−３）で表される化合物を水素接触還元でニトロ基を還元することで、式（１）で表されるジアミンが合成できる。 A compound in which Y is 1,4-phenylene and n is 0 can be synthesized by the route shown below.

In the above scheme 5, a commercially available 5-bromoindole or 6-bromoindole represented by (S5-1) and a commercially available 4-aminophenylboronic acid are subjected to a coupling reaction using a palladium catalyst (S5-2). To obtain a compound represented by: Next, it is reacted with 4-fluoronitrobenzene in the presence of a base such as sodium hydride to obtain a compound represented by (S5-3). Subsequently, the diamine represented by the formula (1) can be synthesized by reducing the nitro group by hydrogen catalytic reduction of the compound represented by (S5-3).

  Next, the polyamic acid of the present invention will be specifically described. By reacting diamine (1) with tetracarboxylic dianhydride in a solvent, a solution containing polyamic acid, partially imidized polyamic acid, or a mixture thereof is obtained. In the following description, these solutions may be referred to as varnishes. Furthermore, the varnish containing a polyimide is obtained by ring-closing the polyamic acid contained in these varnishes, the partially imidized polyamic acid, or a mixture thereof by a dehydration reaction. In the present invention, the diamine (1) may be used alone, but two or more diamines (1) may be combined. Moreover, the diamine represented by Formula (1) and other well-known diamine can also be used together. In the following description, polyamic acids, such as polyamic acids, or partially imidized polyamic acids, or mixtures thereof, and polyamic acids, or partially imidized polyamic acids, or mixtures thereof are dehydrated and cyclized. The polyimides thus obtained are collectively referred to as polymers.

  The molecular weight of the polymer of the present invention is a weight average molecular weight measured by a gel permeation chromatography (GPC) method, preferably 1,000 to 500,000, more preferably 10,000 to 250,000. . If the weight average molecular weight is 10,000 or more, the sublimation of the polymer can be suppressed in the substrate baking step when forming the alignment film, and if the weight average molecular weight is 250,000 or less, the solubility in the solvent is reduced. This is because it is possible to prevent the precipitation of the polymer content when applying the alignment agent to the substrate.

In the present invention, there is no reason to further limit tetracarboxylic dianhydride, but specific examples of tetracarboxylic dianhydride that are preferable for use are shown below.

  These tetracarboxylic dianhydrides may be used alone or in combination of two or more. Among these tetracarboxylic dianhydrides, particularly preferred examples are acid anhydride (A1), acid anhydride (A2), and acid anhydride (A20). By using at least one of these, A liquid crystal display element having a high voltage holding ratio can be provided.

  When preparing the polymer of the present invention, a diamine represented by the formula (1) and a known diamine not represented by the formula (1) can be used in combination as long as the effects of the present invention are not impaired. At this time, in order to maximize the effects of the present invention, the content ratio of the diamine represented by the formula (1) is 0.5 to 95 mol% when the total amount of diamine is 100 mol%. , Preferably 5 to 90 mol%.

Preferred examples of known diamines are diamines selected from the group of compounds represented by formula (II) to formula (VIII) shown below. At least one of these diamines can be used in combination with the diamine (1). In addition, the diamine not represented by Formula (II)-Formula (VIII) can also be used together.

In the formulas (II) to (VIII), m is an integer of 1 to 12, and G ¹ is independently a single bond, —O—, —S—, —S—S—, —SO ₂ —, _{-CO -, - CONH -, -} NHCO -, - C (CH 3) 2 -, - C (CF 3) 2 -, - (CH 2) k -, - O- (CH 2) k -O-, or _{-S- (CH 2) k -S -} , - N (CH 3) - (CH 2) k -N (CH 3) - is a, k is an integer from 1 to 12; ^{G 2} is independently A single bond, —O—, —S—, —CO—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ — or alkylene having 1 to 3 carbon atoms; cyclohexane ring and benzene Any hydrogen in the ring may be replaced with fluorine or —CH ₃ . In formula (III), it is preferred that the two amino groups are not bonded to the same carbon atom. The amino group in formula (IV) is preferably not bonded to the carbon atom to which G ¹ is bonded.

Specific examples of diamine (II) to diamine (IV) are shown below.

Specific examples of diamine (V) are shown below.

Specific examples of diamine (VI) are shown below.

Specific examples of diamine (VII) are shown below.

Specific examples of diamine (VIII) are shown below.

  Diamine (II) to diamine (VIII) can adjust the pretilt angle of liquid crystal molecules to 0 ° to 3 ° by using at least one of these diamines and the diamine (1) of the present invention in combination. It is suitable as an alignment film material for IPS.

In order to obtain an alignment film for IPS having a higher voltage holding ratio, it is preferable to use diamine (VI-1) or diamine (VI-2) in combination.

  In order to obtain an alignment film having a lower residual DC, it is preferable to use diamine (VI-14), diamine (VI-15) or diamine (VI-22) in combination, and particularly to use diamine (VI-22) in combination. Is preferred.

  In order to obtain an alignment film that improves the black display characteristics of the liquid crystal display element, it is preferable to use a diamine represented by diamine (VI-10) or diamine (VIII-3) in combination.

Other known diamines include diamines having a side chain structure. Examples of known diamines having a side chain structure are the following diamine (IX) to diamine (XII). At least one of these diamines can be used in combination with the diamine (1). At least one of diamine (II) to diamine (VIII) and at least one of diamine (IX) to diamine (XII) may be used in combination with diamine (1). In the present invention, diamines other than these may be used in addition to diamine (II) to diamine (XII).

In formula (IX), G ³ is a single bond, —O—, —COO—, —OCO—, —CO—, —CONH— or — (CH ₂ ) _k —, and k is an integer of 1 to 12 It is. R ¹ is an alkyl having 3 to 20 carbon atoms, phenyl, a group having a steroid skeleton, or a group represented by the following formula (IX-S). In this alkyl, any hydrogen may be replaced with fluorine, and any —CH ₂ — may be replaced with —O—, —CH═CH— or —C≡C—. Hydrogen which _{phenyl, -F, -CH 3, -OCH 3} , -OCH 2 F, may be replaced by -OCHF ₂ or -OCF _3. The bonding position of the amino group to the benzene ring is arbitrary, but the bonding position relationship between the two amino groups is preferably meta or para. That is, when the bonding position of the group “R ¹ -G ³ —” is the 1-position, the two amino groups are preferably bonded to the 3-position and 5-position, or the 2-position and 5-position, respectively.

式（IX−Ｓ）中、Ｒ^５は水素、フッ素、炭素数１〜２０のアルキル、炭素数１〜２０のフッ素置換アルキル、炭素数１〜２０のアルコキシ、−ＣＮ、−ＯＣＨ_２Ｆ、−ＯＣＨＦ_２または−ＯＣＦ_３であり、Ｇ^７、Ｇ^８およびＧ^９は結合基であって、これらは独立して単結合、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＯＮＨ−、−ＣＨ＝ＣＨ−または炭素数１〜１２のアルキレンであり、Ａ^２、Ａ^３およびＡ^４は環であって、これらは独立して１，４−フェニレン、１，４−シクロへキシレン、１，３−ジオキサン−２，５−ジイル、ピリミジン−２，５−ジイル、ピリジン−２，５−ジイル、ナフタレン−１，５−ジイル、ナフタレン−２，７−ジイルまたはアントラセン−９，１０−ジイルであり、すべての環において、任意の水素はフッ素または−ＣＨ_３で置き換えられてもよく；ｂ、ｃおよびｄは独立して０〜２の整数であって、これらの合計は１〜５であり；ｂ、ｃまたはｄが２であるとき、２つの結合基は同じであっても異なってもよく、そして２つの環は同じであっても異なってもよい。

In formula (IX-S), R ⁵ represents hydrogen, fluorine, alkyl having 1 to 20 carbons, fluorine-substituted alkyl having 1 to 20 carbons, alkoxy having 1 to 20 carbons, —CN, —OCH ₂ F, — OCHF ₂ or —OCF ₃ , G ⁷ , G ⁸ and G ⁹ are linking groups, which are independently a single bond, —O—, —COO—, —OCO—, —CONH—, —CH = CH- or alkylene having 1 to 12 carbon atoms, A ² , A ³ and A ⁴ are rings, and these are independently 1,4-phenylene, 1,4-cyclohexylene, 1,3 -Dioxane-2,5-diyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl, naphthalene-1,5-diyl, naphthalene-2,7-diyl or anthracene-9,10-diyl , Any water in any ring May be replaced by fluorine or -CH _3; b, c and d are integers of 0 to 2 independently, their sum is in 1 to 5; b, c or d is 2 Sometimes the two linking groups may be the same or different, and the two rings may be the same or different.

In formula (X) and formula (XI), R ² is independently hydrogen or methyl. R ³ is independently hydrogen, alkyl having 1 to 20 carbons, or alkenyl having 2 to 20 carbons. G ⁴ is independently a single bond, —CO— or —CH ₂ —. One hydrogen of the benzene ring in formula (XII) may be replaced with alkyl having 1 to 20 carbons or phenyl.

Wherein (X), 2 radicals _- one of the "NH 2 phenylene -G 4 ^-O-" is attached to the 3 position of the steroid nucleus, it is preferable that the other is bound to 6-position of the steroid nucleus. Formula (XI) 2 radicals in the _- bonded to the benzene rings "NH 2 phenylene -G 4 ^-O-", it is preferred for the bonding position of the steroid nucleus, are each meta or para position. In Formula (XI) and Formula (XII), the amino group is preferably bonded to the benzene ring at the meta position or the para position with respect to the bonding position of G ⁴ .

In the formula (XII), R ⁴ is hydrogen or alkyl having 1 to 20 carbon atoms, and any —CH ₂ — in the alkyl having 2 to 20 carbon atoms in the alkyl is —O— or —CH═CH. -Or -C≡C- may be substituted. G ⁵ is —O— or alkylene having 1 to 6 carbon atoms. A ¹ is 1,4-phenylene or 1,4-cyclohexylene, G ⁶ is a single bond or alkylene having 1 to 3 carbon atoms, and a is 0 or 1. Binding position of the amino group on the benzene ring is preferably a meta or para position with respect to the binding position of G ^5.

Specific examples of diamine (IX) are shown below.

Specific examples of diamine (X) are shown below.

Specific examples of diamine (XI) are shown below.

Specific examples of diamine (XII) are shown below.

  Diamine (IX-1) to diamine (IX-4), diamine (IX-25) to diamine (IX-28), and diamine (XII-1) to diamine (XII-6) are at least one of these. By using in combination with the diamine (1) of the present invention, the pretilt angle of the liquid crystal molecules can be adjusted to 3 ° to 15 °, and therefore, it is suitable as an alignment film material for TN, STN, and OCB.

  TN, STN, OCB that has a higher voltage holding ratio, can suppress residual DC, and can stably give a desired pretilt angle to liquid crystal molecules regardless of the conditions of the alignment film formation step. As a raw material for the alignment film, at least one of diamine (IX-2), diamine (XII-1), diamine (XII-4) and diamine (XII-6) may be used in combination with diamine (1). preferable.

  Diamine (IX-7), Diamine (IX-8), Diamine (IX-13) to Diamine (IX-16), Diamine (IX-29) to Diamine (IX-33), Diamine (X-1) to Diamine (X-4), diamine (XI-1) to diamine (XI-4), and diamine (XII-7) to diamine (XII-11) use at least one of these in combination with diamine (1). Therefore, the pretilt angle of the liquid crystal molecules can be adjusted to 90 °, which is suitable as a raw material for alignment films for VA.

  An alignment film for VA that has a higher voltage holding ratio, can suppress residual DC, and can stably give a predetermined desired pretilt angle to liquid crystal molecules regardless of the conditions of the alignment film forming step. As a raw material, it is preferable to use at least one of diamine (IX-7), diamine (IX-8), diamine (IX-13), and diamine (IX-14) in combination with diamine (1).

ここに、Ｒ^６は独立して炭素数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る。Ｒ^７およびＲ^８は独立して炭素数１〜３のアルキルまたはフェニルである。そしてｆは１〜１０の整数である。これらのシロキサン系ジアミンの使用量は本発明の効果を損なわない範囲であれば、特に限定されるものではない。 Furthermore, examples of the diamine that can be used in combination with the diamine of the present invention include siloxane-based diamines containing a siloxane bond. The siloxane-based diamine is not particularly limited, but a diamine represented by the formula (S1) is preferably used.

Here, R ⁶ is independently alkylene having 1 to 6 carbon atoms, phenylene, or alkyl-substituted phenylene. R ⁷ and R ⁸ are independently alkyl having 1 to 3 carbon atoms or phenyl. And f is an integer of 1-10. The amount of these siloxane-based diamines is not particularly limited as long as the effects of the present invention are not impaired.

  The liquid crystal aligning agent of this invention is demonstrated. The liquid crystal aligning agent of this invention is a polymer solution containing 1 or more chosen from the polymer of this invention. The specific example of the liquid crystal aligning agent of this invention is obtained by removing a solvent from the solution of the polyamic acid of this invention obtained by making diamine (1) and acid dianhydride react, and this polyamic acid solution. A solution of polyamic acid obtained by dissolving a polymer of polyamic acid obtained in a solvent, and a mixture thereof. The liquid crystal aligning agent of the present invention may be the reaction solution itself used for the preparation of the polymer of the present invention, but the polymer obtained by distilling off the solvent from the reaction solution was used for this reaction. It may be a solution dissolved in a different solvent.

  The solvent used in the liquid crystal aligning agent of the present invention is not particularly limited. For example, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), Examples thereof include ethylene glycol monobutyl ether (BC), ethylene glycol monoethyl ether, and γ-butyrolactone. In the present invention, two or more selected from the above solvents may be mixed and used. Further, solvents other than those described above may be used as long as the polymer of the present invention is soluble.

  The liquid crystal aligning agent of the present invention may further include one or more selected from all known polymers in order to develop better properties as an alignment film. At this time, the preferable ratio of the polymer of the present invention in all the polymers is 50 to 100% by weight, and more preferable ratio is 70 to 100% by weight in order to express the effect of the present invention. Examples of such polymers include polyamides, polyurethanes, polyureas, polyesters, polyepoxides, polyester polyols, silicon-modified polyurethanes, silicon-modified polyesters, and the like.

  The ratio of the polymer contained in the liquid crystal aligning agent of this invention is not specifically limited, What is necessary is just to select an optimal value according to the process at the time of producing a liquid crystal display element. Usually, in order to suppress unevenness and pinholes at the time of application to a glass substrate, it is preferably 0.1 to 30% by weight, more preferably 1 to 10% by weight, based on the total weight of the liquid crystal aligning agent.

  If an organosilicon compound is added to the liquid crystal aligning agent of the present invention, it becomes possible to adjust the adhesion and hardness of the alignment film to the glass substrate, and to improve the display defect due to the polyimide being scraped by rubbing or the like. it can. The organosilicon compound added to the liquid crystal aligning agent of the present invention is not particularly limited, and examples thereof include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, vinyltrimethoxysilane, N- (2-aminoethyl)- 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3 A silane coupling agent such as glycidoxypropylmethyldimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, a silicone oil such as dimethylpolysiloxane, polydimethylsiloxane, and polydiphenylsiloxane; To, aminopropyl triethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, be added 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane preferred.

  The addition ratio of the organosilicon compound to the liquid crystal aligning agent is not particularly limited as long as display defects can be improved without impairing the properties required for the alignment film. However, when a large amount of these is added, alignment failure of the liquid crystal occurs when the alignment film is formed. Therefore, these concentrations are preferably 0.01 to 50% by weight, more preferably 0.1 to 20% by weight, based on the total weight of the polymer contained in the liquid crystal aligning agent.

  A liquid crystal aligning agent capable of giving a desired pretilt angle can also be prepared by mixing different types of polymers. This is based on the fact that when a plurality of polymers having different surface energies are mixed, when these polymers become thin films, the polymer having a small surface energy tends to segregate on the surface. By performing such a polymer blend, a layer of a component (referred to as polymer A) that imparts a pretilt angle to the liquid crystal molecules and exhibits good liquid crystal orientation is formed on the surface of the alignment film, and is formed on the coated substrate side. A layer of the component (polymer B) that exhibits good electrical characteristics can be formed. That is, an alignment film excellent in both of these characteristics can be obtained. This method is disclosed in JP-A-8-43831.

  Polymer blending can also be performed in the liquid crystal aligning agent of the present invention. Since the polymer of the present invention becomes an alignment film having excellent electrical properties, it is suitable as a component of polymer B. Further, as described above, the polymer of the present invention can be used as a component of the polymer A by appropriately combining the diamine of the present invention represented by the formula (1) with another diamine.

  The mixing ratio of the polymer A and the polymer B can be arbitrarily selected between 1 wt% and 99 wt%, respectively. However, the ratio of the polymer A that is preferable for developing good electrical properties while maintaining good liquid crystal alignment characteristics and a pretilt angle is 1 to 50% by weight based on the total weight of the polymer, more preferably 5 to 5%. 30% by weight.

  It is also important to add a crosslinking agent that reacts with the carboxylic acid residue of the polyamic acid to the liquid crystal aligning agent of the present invention in order to prevent deterioration of characteristics over time and deterioration due to the environment. Examples of such a crosslinking agent include polyfunctional epoxies and isocyanate materials as described in Japanese Patent No. 3049699, Japanese Patent Application Laid-Open No. 2005-275360, Japanese Patent Application Laid-Open No. 10-212484, and the like. Further, a material that reacts with the crosslinking agent itself to form a polymer having a network structure and improves the strength of the polyamic acid or the polyimide film can be used for the same purpose as described above. Examples of such a crosslinking agent include polyfunctional vinyl ethers, maleimide derivatives, or bisallyl nadiimide derivatives as described in JP-A-10-310608, JP-A-2004-341030, and the like. The crosslinking agent used in the present invention may be other than these. When a cross-linking agent is used, the preferred ratio for expressing the effects of the present invention is 0.05 to 0.5, more preferably 0.1 to 0.3, in terms of the weight ratio to the polymer of the present invention. It is.

  The viscosity of the liquid crystal aligning agent of the present invention is preferably 5 to 100 mPa · s, more preferably 10 to 80 mPa · s, although it depends on the coating method, the type and concentration of the polymer, the type of solvent, and the like. In order to obtain a sufficient film thickness, the viscosity is desirably larger than 5 mPa · s, and in order not to cause printing unevenness, the viscosity is desirably smaller than 100 mPa · s. However, when printing by the ink jet method, one having a viscosity of 5 mPa · s or less can be used.

  Next, the liquid crystal display element of the present invention will be described. The liquid crystal display element of the present invention includes (1) a pair of substrates disposed opposite to each other, (2) a liquid crystal alignment film formed on the surfaces of the pair of substrates opposed to each other, and (3) between the pair of substrates. A liquid crystal layer sandwiched between the two. Electrodes may be disposed on both of the pair of substrates. However, in the case of an IPS liquid crystal display element, an electrode (which may be a comb-shaped or zigzag structure electrode) is disposed on one of the pair of substrates. ing.

  The liquid crystal alignment film is a liquid crystal alignment film formed by applying the liquid crystal aligning agent of the present invention to the substrate and heating. Here, the film thickness of the liquid crystal alignment film is preferably 10 to 300 nm, and more preferably 30 to 100 nm. The liquid crystal alignment film is preferably rubbed.

  The pair of substrates with electrodes arranged opposite to each other is preferably a transparent substrate (for example, a glass substrate).

  The liquid crystal layer sandwiched between the pair of substrates includes a liquid crystal composition. Here, the liquid crystal composition is not particularly limited, and either a liquid crystal composition having a positive dielectric anisotropy or a liquid crystal composition having a negative dielectric anisotropy may be used depending on the driving mode. it can. Examples of preferable liquid crystal compositions having a positive dielectric anisotropy include Japanese Patent No. 3086228, Japanese Patent No. 2635435, Japanese Patent Laid-Open No. 5-501735, Japanese Patent Laid-Open No. 8-157826, Japanese Patent Laid-Open No. 8- No. 231960, JP-A-9-241644 (EP882722A1), JP-A-9-302346 (EP806466A1), JP-A-8-199168 (EP722998A1), JP-A-9-235552, JP-A-9-255556. JP-A-9-241643 (EP882711A1), JP-A-10-204016 (EP844229A1), JP-A-10-204436, JP-A-10-231482, JP-A-2000-087040, Special Disclosure in Japanese Laid-Open Patent Publication No. 2001-48822 To have.

  The liquid crystal composition used in the VA liquid crystal display element can be various liquid crystal compositions having negative dielectric anisotropy. Examples of preferred liquid crystal compositions include JP-A-57-141432, JP-A-2-4725, JP-A-4-224858, JP-A-8-40953, JP-A-8-104869, Japanese Laid-Open Patent Publication No. 10-168076, Japanese Laid-Open Patent Publication No. 10-168453, Japanese Laid-Open Patent Publication No. 10-236989, Japanese Laid-Open Patent Publication No. 10-236990, Japanese Laid-Open Patent Publication No. 10-236992, Japanese Laid-Open Patent Publication No. 10-236993, Japanese Laid-open Patent Publication No. -236994, JP-A-10-237000, JP-A-10-237004, JP-A-10-237024, JP-A-10-237035, JP-A-10-237075, JP-A-10-237076 JP, 10-237448, (EP967261A1), JP 10-28787. No. 1, JP-A-10-287875, JP-A-10-291945, JP-A-11-029581, JP-A-11-080049, JP-A-2000-256307, JP-A-2001-019965. JP-A-2001-072626, JP-A-2001-192657, and the like.

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

  The liquid crystal display element of the present invention may have other members. For example, in a color display TFT type liquid crystal element using a thin film transistor, a thin film transistor, an insulating film, a protective film, a signal electrode, a pixel electrode, and the like are formed on a first transparent substrate, and the second transparent substrate is formed. A black matrix, a color filter, a planarization film, a pixel electrode, and the like that block light outside the pixel region are included.

  In a VA liquid crystal display element, in particular, an MVA liquid crystal display element, a minute projection called a domain is formed on a first transparent substrate. In addition, a spacer may be formed for adjusting the cell gap between the substrates.

  The liquid crystal display element of the present invention is manufactured by an arbitrary method. For example, (1) a liquid crystal aligning agent coating step on the two transparent substrates, (2) a drying step of the applied liquid crystal aligning agent, ( 3) Heat treatment step for dehydrating and ring-closing reaction of the dried liquid crystal alignment agent, (4) Alignment treatment step of the obtained alignment film, (5) Liquid crystal between the two substrates after being bonded together It is manufactured by a method including an enclosing step, or a step of laminating the other substrate after dropping the liquid crystal on one substrate.

  As an application method in the step of 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.

  As a method of the heat treatment step necessary for the drying step and the dehydration / ring-closure reaction, heat treatment in an oven or an infrared furnace, heat treatment on a hot plate, and the like are generally known. These methods are also applicable in the present invention. The drying step is preferably performed at a relatively low temperature (50 to 100 ° C.) within a range where the solvent can be evaporated. In general, the heat treatment step is preferably performed at a temperature of about 150 to 300 ° C.

  The alignment process is usually a rubbing process for OCB type liquid crystal display elements, TN type liquid crystal display elements, STN type liquid crystal display elements, and IPS type liquid crystal display elements. In many cases, the rubbing treatment is not performed in the VA liquid crystal display element, but it may be performed.

  Next, an adhesive is applied and bonded onto one substrate, and liquid crystal is injected under reduced pressure. In the case of the dropping injection method, the liquid crystal is dropped on the substrate before bonding, and then the other substrate is bonded. The liquid crystal display element of the present invention is produced by curing the adhesive used for bonding with heat or ultraviolet rays.

  A polarizing plate (polarizing film), a wave plate, a light scattering film, a drive circuit, and the like may be mounted on the liquid crystal display element of the present invention.

  The liquid crystal display element of the present invention is characterized by high voltage holding ratio and low residual DC. This is because the liquid crystal alignment film of the liquid crystal display element of the present invention is formed of a liquid crystal alignment agent containing a polyamic acid synthesized using a compound represented by diamine (I) or a derivative thereof. . This is also explained in the examples described later.

  EXAMPLES Hereinafter, although the diamine of this invention, the liquid crystal aligning agent obtained by using this diamine, and a liquid crystal display element are demonstrated in detail by an Example, this invention is not limited to these Examples. In the examples, 1H-NMR measurement was performed in deuterated dimethyl sulfoxide. The molecular weight was measured using GPC, polystyrene as a standard solution, and DMF as eluent. In the following examples, the unit liter of volume is indicated by L. Therefore, mL means milliliter.

First, an evaluation method of the liquid crystal display element used in the examples will be described.
(1) Residual DC
After a 1 V DC voltage was superimposed on a 30 Hz, 3 V rectangular wave for 30 minutes, the flicker erasing voltage after 10 minutes was measured, and the absolute value of this value was defined as the residual DC. It can be said that the smaller the residual DC is, the better the less seizure.
(2) Voltage holding ratio The method described in “Mizushima et al., Proceedings of the 14th Liquid Crystal Symposium p78” was followed. The measurement was performed by applying a rectangular wave having a gate width of 69 μs, a frequency of 0.3 Hz, and a wave height of ± 5.0 V to the cell. The measurement temperature was 60 ° C.
(3) Pretilt angle The pretilt angle was measured by the crystal rotation method. The wavelength of light used for the measurement is 589 nm.

[Example 1]
<Synthesis of diamine (1-1)>
In a 1 L three-necked flask equipped with a stirrer, a thermometer and a nitrogen gas inlet, 11.4 g (0.46 mol) of 60% sodium hydride was added, and 100 mL of DMF was added. The solution was cooled to 5 ° C., and a solution prepared by dissolving 30 g (0.23 mol) of commercially available 5-aminoindole in 200 mL of DMF was added dropwise thereto. The solution was warmed to room temperature and stirred for 1 hour under a nitrogen atmosphere. The solution was cooled again to 5 ° C., and a solution obtained by dissolving 39 g (0.28 mol) of 4-fluoronitrobenzene in 200 mL of DMF was added dropwise thereto. The solution was warmed to room temperature and stirred for 12 hours under a nitrogen atmosphere. The reaction solution was extracted by pouring into a mixed solvent of 500 mL of ethyl acetate and 500 mL of pure water, and the organic layer was washed 3 times with 500 mL of pure water. The organic layer was dried over anhydrous sodium sulfate, then anhydrous sodium sulfate was removed, and the solvent was distilled off under reduced pressure to obtain crude crystals. The crude crystals were separated and purified by column chromatography (toluene: ethyl acetate = 5: 1 (v / v)) to obtain N- (4-nitrophenyl) -5-aminoindole (yield 35.0 g, yield). 60%).

35.0 g (0.14 mol) of the obtained N- (4-nitrophenyl) -5-aminoindole and 3.5 g of palladium carbon powder were placed in an autoclave reaction tube, and 350 mL of ethanol and 35 mL of ethyl acetate were added. The system was placed in a hydrogen atmosphere, and the mixture was stirred at room temperature for 12 hours under a hydrogen pressure of 0.49 MPa. The palladium carbon powder was removed, and the resulting solution was concentrated to obtain crude crystals. The crude crystals were separated and purified by column chromatography (toluene: ethyl acetate = 3: 1 (v / v)) to obtain diamine (1-1) (N- (4-aminophenyl) -5-aminoindole). (Yield 28.8 g, 92% yield).
¹ H-NMR (ppm); 3.53 (—NH ₂ , br.s, 2H), 3.74 (—NH ₂ , br.s, 2H), 6.43-7.25 (arm.H, m, 9H).

[Example 2]
<Synthesis of diamine (1-2)>
A diamine (1-2) (N- (4-aminophenyl) -6-aminoindole) was obtained according to the method described in Example 1 except that 5-nitroindole was replaced with 6-nitroindole. .
¹ H-NMR (ppm); 3.52 (—NH ₂ , br.s, 2H), 3.75 (—NH ₂ , br.s, 2H), 5.85-8.18 (arm.H, m, 9H).

[Example 3]
<Synthesis of diamine (1-5)>
According to the method described in Tetrahedron Letters 41, 1815-1818 (2000), 50 g (0.25 mol) of 4,4′-diaminodiphenylmethane was added to a 1 L three-necked flask equipped with a stirrer, thermometer, cooler and nitrogen gas inlet. ), 18.6 g (0.10 mol) of triethanolamine hydrochloride, 11.3 g (0.05 mol) of tin (II) chloride dihydrate, 1.0 g (0.005 mol) of ruthenium (III) chloride n hydrate. ) And 3.9 g (0.015 mol) of triphenylphosphine were added, and 500 mL of dioxane and 50 mL of pure water were added. The system is under a nitrogen atmosphere. The mixture was stirred at 180 ° C. for 20 hours. After allowing to cool, the reaction solution was poured into 500 mL of 5% hydrochloric acid and extracted with 500 mL of chloroform. The organic layer was washed with 500 mL of pure water three times, and then the organic layer was dried over anhydrous magnesium sulfate. Then, anhydrous magnesium sulfate was removed, and the solvent was distilled off under reduced pressure to obtain crude crystals. Separation and purification by column chromatography (ethyl acetate: hexane = 1: 1 (v / v)) gave bis (5-indolyl) methane (yield 7.3 g, yield 59%).

  To a 1 L three-necked flask equipped with a stirrer, a thermometer and a nitrogen gas inlet, 1.3 g (0.056 mol) of 60% sodium hydride was added, and 10 mL of DMF was added. The solution was cooled to 5 ° C., and a solution prepared by dissolving 7 g (0.028 mol) of bis (5-indolyl) methane in 20 mL of DMF was added dropwise thereto. The solution was warmed to room temperature and stirred for 1 hour under a nitrogen atmosphere. The solution was cooled again to 5 ° C., and a solution prepared by dissolving 4.7 g (0.034) of 4-fluoronitrobenzene in 20 mL of DMF was added dropwise thereto. The solution was warmed to room temperature and stirred for 12 hours under a nitrogen atmosphere. The reaction solution was extracted by pouring into a mixed solvent of 100 mL of ethyl acetate and 100 mL of pure water, and the organic layer was washed 3 times with 100 mL of pure water. The organic layer was dried over anhydrous sodium sulfate, then anhydrous sodium sulfate was removed, and the solvent was distilled off under reduced pressure to obtain crude crystals. The crude crystals were separated and purified by column chromatography (toluene: ethyl acetate = 5: 1 (v / v)) to obtain bis (5-N- (4-nitrophenyl) indolyl) methane (yield 9.3 g, Yield 68%).

In a reaction tube for autoclave, 9.0 g (0.018 mol) of the obtained bis (5-N- (4-nitrophenyl) indolyl) methane and 0.9 g of palladium carbon powder are added, and 100 mL of ethanol and 10 mL of ethyl acetate are added. It was. The system was placed in a hydrogen atmosphere, and the mixture was stirred at room temperature for 12 hours under a hydrogen pressure of 0.49 MPa. The palladium carbon powder was removed, and the resulting solution was concentrated to obtain crude crystals. The crude crystals were separated and purified by column chromatography (toluene: ethyl acetate = 3: 1 (v / v)), and diamine (1-5) (bis (5-N- (4-aminophenyl) indolyl) methane) was obtained. Obtained (yield 7.1 g, yield 91%).
¹ H-NMR (ppm); 3.86 (—CH ₂ —, s, 2H), 4.1 (—NH ₂ , br. S, 4H), 6.52 to 8.72 (arm. H, m , 18H).

[Example 4]
<Synthesis of diamine (1-9)>
According to the method described in Example 3, except that 4,4′-diaminodiphenylmethane was replaced with 1,3-bis (4-aminophenyl) propane, diamine (1-9) (1,3-bis (5 -N- (4-aminophenyl) indolyl) propane).
¹ H-NMR (ppm); 1.95 (—CH ₂ —, q, 2H), 2.62 (—CH 2 —, t, 4H), 3.72 (—NH ₂ , br.s, 4H), 6.5-1-8.78 (arm.H, m, 18H).

[Example 5]
<Synthesis of diamine (1-28)>
According to the method described in Example 3, except that 4,4′-diaminodiphenylmethane was replaced with 4,4′-diaminodiphenyl ether, diamine (1-28) (bis (5-N- (4-aminophenyl) Indolyl) ether).
_{^{1 H-NMR (ppm);}} 3.79 (-NH 2, br.s, 4H), 6.52-8.04 (arm.H, m, 18H).

[Example 6]
<Synthesis of diamine (1-31)>
According to the method described in Example 3, except that 4,4′-diaminodiphenylmethane was replaced with N, N′-dimethyl-N, N′-bis (4-aminophenyl) ethylenediamine, diamine (1-31) (N, N′-dimethyl-N, N′-bis (5-N- (4-aminophenyl) indolyl) ethylenediamine) was obtained.
_{^{1 H-NMR (ppm);}} 2.75 (> NCH 3, s, 4H), 3.58 (-CH 2 -, s, 4H), 3.69 (-NH 2, br.s, 4H), 6.5-2.7.6 (arm. H, m, 18H).

[Example 7]
<Synthesis of diamine (1-35)>
In a 1 L three-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet, 20 g (0.10 mol) of commercially available 5-bromoindole and 15.1 g (0.11 mol) of commercially available 4-aminophenylboronic acid Dichlorobis (triphenylphosphine) palladium (II) 0.35 g (0.0005 mol), potassium carbonate 20.7 g (0.15 mol) and tetrabutylammonium bromide 8.1 g (0.025 mol) were added, ethanol 150 mL, toluene 75 mL and 100 mL of pure water were added. The mixture was heated to reflux for 3 hours under a nitrogen atmosphere. After cooling, the reaction solution was poured into water, extracted with 200 mL of toluene, and the organic layer was washed 3 times with 200 mL of pure water. The organic layer was dried over anhydrous sodium sulfate, then anhydrous sodium sulfate was removed, and the solvent was distilled off under reduced pressure to obtain crude crystals. The crude crystals were separated and purified by column chromatography (toluene: ethyl acetate = 5: 1 (v / v)) to obtain 5- (4-aminophenyl) indole (yield 17.9 g, yield 86%).

  In a 1 L three-necked flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet, 3.8 g (0.16 mol) of 60% sodium hydride was added, and 40 mL of DMF was added. The solution was cooled to 5 ° C., and a solution in which 16.7 g (0.08 mol) of 5- (4-aminophenyl) indole was dissolved in 200 mL of DMF was added dropwise thereto. The solution was warmed to room temperature and stirred for 1 hour under a nitrogen atmosphere. The solution was cooled again to 5 ° C., and a solution prepared by dissolving 14.1 g (0.10 mol) of 4-fluoronitrobenzene in 150 mL of DMF was added dropwise thereto. The solution was warmed to room temperature and stirred for 12 hours under a nitrogen atmosphere. The reaction solution was extracted by pouring into a mixed solvent of 500 mL of ethyl acetate and 500 mL of pure water, and the organic layer was washed 3 times with 500 mL of pure water. The organic layer was dried over anhydrous sodium sulfate, then anhydrous sodium sulfate was removed, and the solvent was distilled off under reduced pressure to obtain crude crystals. The crude crystals were separated and purified by column chromatography (toluene: ethyl acetate = 5: 1 (v / v)), and N- (4-nitrophenyl) -5- (4-aminophenyl) indole (yield 16.6 g, Yield 63%).

Into an autoclave reaction tube, 16.0 g (0.049 mol) of N- (4-nitrophenyl) -5- (4-aminophenyl) indole and 1.6 g of palladium carbon powder were added, and 200 mL of ethanol and 20 mL of ethyl acetate were added. It was. The system was placed in a hydrogen atmosphere, and the mixture was stirred at room temperature for 12 hours under a hydrogen pressure of 0.49 MPa. The palladium carbon powder was removed, and the resulting solution was concentrated to obtain crude crystals. The crude crystals were separated and purified by column chromatography (toluene: ethyl acetate = 3: 1 (v / v)), and diamine (1-35) (N- (4-aminophenyl) -5- (4-aminophenyl) Indole) was obtained (yield 13.3 g, yield 91%).
¹ H-NMR (ppm); 3.53 (—NH ₂ , br.s, 2H), 3.74 (—NH ₂ , br.s, 2H), 6.42-8.18 (arm.H, m, 13H).

[Example 8]
<Preparation of polyamic acid>
In a 200 mL three-necked flask equipped with a thermometer, a stirrer and a nitrogen gas inlet, (1-1) 2.59 g was placed and dissolved in dehydrated NMP 60 g. While maintaining the solution at 5 ° C., 1.14 g of compound (A14) and 1.27 g of compound (A1) were added. The solution was warmed to room temperature and reacted for 12 hours under a nitrogen atmosphere. Then, 10 g of γ-butyrolactone and 25 g of BC were added, and the mixture was further stirred for 3 hours. In order to reduce the viscosity of the obtained solution, the solution was heated and stirred at 60 ° C. until the viscosity of the solution reached 35 mPa · s to obtain a solution having a polyamic acid concentration of 5% by weight. This solution is designated as varnish A. The weight average molecular weight of the polyamic acid in this varnish A was 64,000.

[Examples 9 to 25, Comparative Examples 1 and 2, and Reference Example 1]
Polyamic acid was produced in the same manner as in Example 8 using diamine and tetracarboxylic dianhydride as shown in Table 1, and varnishes B to U were prepared.
<Table 1>

[Example 26]
<Production of measurement cell for electrical characteristics>
Varnish A prepared in Example 8 was diluted with a mixed solvent of NMP / BC = 6/4 (v / v) to adjust the polyamic acid concentration to 3% by weight, and this was used as a coating varnish.

  This coating varnish was coated on a glass substrate with an ITO electrode by a spinner method. The coating conditions were 2,000 rpm and 15 seconds. After coating, the substrate was heated to 80 ° C. and pre-baked for 5 minutes, and then heat-treated at 210 ° C. for 20 minutes to form a liquid crystal alignment film having a thickness of about 80 nm. The obtained alignment film was rubbed. The rubbing treatment was performed using a rubbed cloth made of rayon with a hair length of 1.9 mm under the conditions of a push-in amount of 0.40 mm, a stage moving speed of 60 mm / sec, and a roller rotation speed of 1,000 rpm.

  The glass substrate after the rubbing treatment was subjected to ultrasonic cleaning for 5 minutes in ultrapure water and then dried in an oven at 120 ° C. for 30 minutes. A 7 μm gap agent was sprayed on one substrate, and the other substrate was overlapped with the gap agent sandwiched between them and sealed with an epoxy curing agent to produce an anti-parallel cell with a gap of 7 μm. The following liquid crystal composition A was injected into this cell as a liquid crystal material, and the injection port was sealed with a photocurable resin. The cell was then heat-treated at 110 ° C. for 30 minutes to obtain a cell for measuring voltage holding ratio, residual DC and pretilt angle.

<Liquid crystal composition A>

  Using the fabricated cell, the voltage holding ratio, the residual DC, and the pretilt angle were measured by the above-described method, and were found to be 96.2%, 1.8 mV, and 1.7 °, respectively.

[Examples 27 to 43 and Comparative Examples 3 to 4]
Using varnish B to varnish T, cells were prepared according to the method described in Example 26, and the voltage holding ratio, residual DC, and pretilt angle were measured. The measurement results are shown in Table 2 (Example 26 is also shown again). However, the alignment film formed using varnish E, varnish K, and varnish Q was not rubbed, and the liquid crystal material to be injected was replaced with liquid crystal composition A and liquid crystal composition B was used.

<Liquid crystal composition B>

[Examples 44 and 45]
<Evaluation of electrical properties of blend alignment agent>
Varnish AU was prepared by mixing varnish A and varnish U at a weight ratio of 8: 2. A cell was produced in accordance with the method described in Example 26 using this varnish AU. Varnish BU in which varnish B and varnish U were mixed at a weight ratio of 8: 2 was prepared, and a cell was prepared using varnish BU in the same manner as varnish AU. Table 2 shows the results of measuring the voltage holding ratio, residual DC, and pretilt angle for these cells.

<Table 2>

[Examples 46 to 50 and Comparative Examples 5 to 6]
<Confirmation of storage stability>
Varnish A, varnish B, varnish F, varnish J, varnish AU, varnish S and varnish T were prepared and stored at −20 ° C. for 60 days, and the stored varnish was used according to the method described in Example 26. A cell was prepared, and the voltage holding ratio, residual DC, and pretilt angle were measured. The measurement results are shown in Table 3.
<Table 3>

[Example 51]
<Preparation of polyimide>
In a 200 mL eggplant flask, 100 g of varnish A was weighed, 9.5 g (0.09 mol) of acetic anhydride and 4.4 g (0.06 mol) of pyridine were added, and the mixture was stirred at 120 ° C. for 3 hours. The solution was poured into 1000 mL of pure water to obtain 4.5 g of polyimide. The weight average molecular weight of this polyimide was 49,000, and the imidation ratio of this polyimide was 94% from 1H-NMR measurement. 4 g of the obtained polyimide was dissolved in 76 g of a NMP-GBL-BC mixed solvent (volume ratio 1: 1: 1) to obtain a varnish V having a polyimide concentration of 5%.

[Example 52]
A cell was prepared using the varnish V according to the method described in Example 26, and the voltage holding ratio, residual DC, and pretilt angle were measured. The results were 95.9%, 4.2 mV, and 1.6, respectively. °.

[Comparative Example 7]
According to the method described in Example 8, except that diamine (1-1) was replaced with N, N′-bis (4-aminophenyl) -1,4-piperazine described in JP-A-10-104633. , Varnish W was obtained.

  In a 200 mL eggplant flask, 100 g of varnish W was weighed, to which 8.2 g (0.08 mol) of acetic anhydride and 3.8 g (0.05 mol) of pyridine were added and heated to 120 ° C. Even when the temperature of the solution was increased to 180 ° C., the precipitate did not dissolve.

[Example 53]
<Synthesis of diamine (1-11)>
A 500 mL three-necked flask equipped with a stirrer, a thermometer and a nitrogen gas inlet was charged with 29.0 g (102 mmol) of commercially available 5-iodoindole and 17.0 g (122 mmol) of potassium carbonate, and 200 mL of DMF was added. A solution obtained by dissolving 17.3 g (122 mmol) of commercially available 4-fluoronitrobenzene in 100 mL of DMF was added thereto, and the mixture was stirred at 140 ° C. for 2 hours in a nitrogen atmosphere. The reaction solution was extracted by pouring into a mixed solvent of 500 mL of ethyl acetate and 500 mL of pure water, and the organic layer was dried over anhydrous magnesium sulfate. Magnesium sulfate was filtered off, and the solvent was distilled off under reduced pressure to obtain crude crystals. The obtained crude crystals were recrystallized from toluene to obtain N- (4-nitrophenyl) -5-iodoindole (yield 33 g, yield 83%).

  In a 500 mL three-necked flask equipped with a stirrer, a thermometer and a nitrogen gas inlet, 33 g (91 mmol) of the obtained N- (4-nitrophenyl) -5-iodoindole and bis (triphenylphosphine) palladium (II) dichloride were obtained. 3.2 g (4.6 mmol) and 0.87 g (4.6 mmol) of copper (I) iodide were added, and 300 mL of triethylamine was added. 10.7 g (109 mmol) of commercially available trimethylsilylacetylene was added thereto, and the mixture was heated to reflux for 6 hours under a nitrogen atmosphere. The reaction solution was extracted by pouring into a mixed solvent of 500 mL of ethyl acetate and 500 mL of pure water, and the organic layer was dried over anhydrous magnesium sulfate. Magnesium sulfate was filtered off, and the solvent was distilled off under reduced pressure to obtain crude crystals of N- (4-nitrophenyl) -5-((trimethylsilyl) ethynyl) -indole (yield 27 g, yield 88%).

  In a 500 mL three-necked flask equipped with a stirrer, a thermometer and a nitrogen gas inlet, 27 g (81 mmol) of the obtained N- (4-nitrophenyl) -5-((trimethylsilyl) ethynyl) -indole was placed, and tetrahydrofuran 200 mL was added. Dissolved. Under a nitrogen atmosphere, the solution was cooled to −78 ° C. with a dry ice-acetone bath, and 85 mL of a commercially available tetrabutylammonium fluoride 1 mol / L solution was added dropwise thereto while keeping the liquid temperature at −78 ° C. After keeping the solution at −78 ° C. and stirring for 2 hours, the reaction solution was poured into a mixed solvent of 500 mL of ethyl acetate and 500 mL of pure water, and the organic layer was dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure to obtain N- (4-nitrophenyl) -5-ethynylindole (yield 17 g, yield 79%).

  Into a 500 mL three-necked flask equipped with a stirrer, a thermometer and an air inlet, 17 g (65 mmol) of the obtained N- (4-nitrophenyl) -5-ethynylindole, 1.3 g (13 mmol) of copper (I) chloride and N, N′-tetramethylethylenediamine 2.5 g (21 mmol) was added, and 100 mL of ethylene glycol dimethyl ether was added. The mixture was stirred at room temperature for 24 hours while feeding air into the system using an air pump for a water tank. The reaction solution was filtered, and the resulting reaction product was washed once with 300 mL of ammonia water and twice with 300 mL of pure water to obtain 1,4-bis (5- (N- (4-nitrophenyl) -indolyl)). -1,3-butadiyne was obtained (yield 14 g, yield 82%).

In a reaction tube for autoclave, 14.0 g (27 mmol) of 1,4-bis (5- (N- (4-nitrophenyl) -indolyl))-1,3-butadiyne obtained and 1.4 g of palladium carbon powder were obtained. And 150 mL of ethanol and 150 mL of ethyl acetate were added. The system was placed in a hydrogen atmosphere, and the mixture was stirred at room temperature for 12 hours under a hydrogen pressure of 0.49 MPa. The palladium carbon powder was removed, and the resulting solution was concentrated to obtain crude crystals. The crude crystals were separated and purified by column chromatography (dichloromethane: methanol = 10: 1 (v / v)) and recrystallized from ethanol to give 1,4-bis (5- (N- (4-aminophenyl) -indolyl. )) Butane was obtained (yield 12 g, yield 91%).
1H-NMR (ppm); 1.74-1.76 (—CH ₂ —, m, 4H) 2.74-2.76 (—CH ₂ —, t, J = 6.4 Hz, 4H); _{76 (-NH 2, br.s, 4H} ), 6.52-7.45 (arm.H, 18H)

[Example 54]
<Synthesis of diamine (1-37)>
A 500 mL three-necked flask equipped with a stirrer, a thermometer and a nitrogen gas inlet was charged with 26.0 g (161 mmol) of commercially available 5-nitroindole and 27.0 g (194 mmol) of potassium carbonate, and 200 mL of DMF was added. A solution prepared by dissolving 38.0 g (242 mmol) of commercially available 5-fluoro-2-nitrophenol in 100 mL of DMF was added thereto, and the mixture was stirred at 140 ° C. for 2 hours in a nitrogen atmosphere. The reaction solution was poured into 1 L of pure water, and the obtained crystals were washed twice with 500 mL of pure water and twice with 500 mL of ethanol and dried to obtain N- (3-hydroxy-4-nitrophenyl) -5-nitroindole. (Yield 45 g, 94% yield).

In an autoclave reaction tube, 45.0 g (150 mmol) of N- (3-hydroxy-4-nitrophenyl) -5-nitroindole and 4.5 g of palladium carbon powder were added, and 500 mL of ethanol was added. The system was placed in a hydrogen atmosphere, and the mixture was stirred at room temperature for 12 hours under a hydrogen pressure of 0.49 MPa. The palladium carbon powder was removed, and the resulting solution was concentrated to obtain crude crystals. The crude crystals were recrystallized from ethanol / pure water = 1: 1 (v / v) to obtain N- (4-amino-3-hydroxyphenyl) -5-aminoindole (yield 30 g, yield 83%). .
_{1H-NMR (ppm); 4.59} (-NH 2, br.s, 2H), 4.66 (-NH 2, br.s, 2H), 6.29-6.30 (= CH-, d , J = 3.0 Hz, 1H), 6.53-7.13 (arm.H, m, 6H), 7.24-7.25 (= CH-, d, J = 3.0 Hz, 1H)

  As described above, the liquid crystal display element using the liquid crystal aligning agent of the present invention exhibits favorable characteristics such as a higher voltage holding ratio and a smaller residual DC as compared with the conventional one. Moreover, it turned out that the liquid crystal aligning agent of this invention is excellent in storage stability, and has high solubility also to the solvent used normally.

Claims (10)

Diamine represented by formula (1):

Here, Y is a single bond or a linear alkylene having 1 to 9 carbon atoms; any —CH ₂ — in the alkylene is —O—, —N (CH ₃ ) —, 1,4-phenylene, 1, May be replaced by 4-cyclohexylene or piperazine-1,4-diyl; n is 0 or 1; and one hydrogen of the benzene ring to which the amino group is bonded is replaced by —OH. Also good. However, when Y is alkylene and n is 0, —CH ₂ — to which the amino group is bonded is not replaced by —O— or —N (CH ₃ ) —.   The diamine according to claim 1, wherein the benzene ring to which the amino group is bonded is a benzene ring not having -OH as a substituent.   The diamine according to claim 1, wherein the benzene ring to which the amino group is bonded is a benzene ring having a substituent -OH at one of the ortho positions with respect to the amino group.   The diamine according to claim 1, wherein Y is a single bond or 1,4-phenylene, and n is 0. Y is a single bond, or an arbitrary —CH ₂ — is a linear alkylene having 1 to 9 carbon atoms which may be replaced by —O— or —N (CH ₃ ) —; and n is 1. Item 4. The diamine according to Item 1.   Obtained by reacting at least one of the diamines of claim 1 or at least one of the diamines of claim 1 with at least one of the other diamines and at least one tetracarboxylic anhydride. Polyamic acid. The polyamic acid according to claim 6, wherein the at least one tetracarboxylic acid anhydride is a tetracarboxylic acid anhydride selected from compounds represented by formulas (A1) to (A63).

  A polyimide obtained by dehydrating and ring-closing the polyamic acid according to claim 6. A liquid crystal aligning agent containing at least one polymer selected from the group consisting of the polyamic acid according to claim 6 and the polyimide according to claim 8 . The liquid crystal display element which has a liquid crystal aligning film obtained from the liquid crystal aligning agent of Claim 9 .