JP6314827B2 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element suitable for providing a liquid crystal display element having excellent display quality.

  The liquid crystal display element is known as a light, thin and low power consumption display device, and has been remarkably developed in recent years.

  The liquid crystal display element is configured by sandwiching and enclosing a liquid crystal layer between a pair of substrates, and orienting liquid crystals in the liquid crystal layer in a predetermined direction between the substrates. In a liquid crystal display element, a liquid crystal responds by applying a voltage to electrodes provided on a pair of substrates, and a desired image can be displayed using an orientation change due to the response of the liquid crystal.

  This liquid crystal display element has various liquid crystal modes in which the initial alignment state of liquid crystal molecules and the form of alignment change by voltage application are different. For example, as an initial alignment state of liquid crystal molecules, a TN (Twisted Nematic) mode in which the liquid crystal is twisted by 90 ° between a pair of substrates is known.

In recent years, among liquid crystal display element display methods, liquid crystal display elements in a vertical alignment (VA) mode in which liquid crystal molecules having negative dielectric anisotropy are aligned perpendicularly to a substrate have been actively developed ( For example, see Patent Documents 1 and 2.)
In this VA mode liquid crystal display element, by applying a voltage, the vertically aligned liquid crystal changes its orientation so as to be parallel to the substrate and toward the predetermined direction while being inclined in a predetermined direction. The VA mode can realize a high contrast ratio, a wide viewing angle, and an excellent response characteristic.

  Since this VA liquid crystal display element enables the above-described liquid crystal orientation changing operation, as the initial orientation state of the liquid crystal when no voltage is applied, the liquid crystal is directed from the normal direction of the substrate toward a predetermined direction in the plane. It is required to form a slightly tilted state.

As the VA liquid crystal display element, there is known an MVA (Multi-domain Vertical Alignment) system in which a protrusion structure is formed on a TFT substrate or a color filter substrate in order to control the tilt direction of the liquid crystal by voltage application.
Further, a PVA (Patterned Vertical Alignment) method is known in which a slit structure is provided in an electrode made of ITO (Indiumtinoxide) or the like of a substrate sandwiching a liquid crystal layer, and the tilt direction of the liquid crystal is controlled by a formed oblique electric field.
Furthermore, a liquid crystal alignment film is provided between the substrate and the liquid crystal layer, this is rubbed, and the liquid crystal molecules are slightly tilted from the normal direction of the substrate toward one direction in the substrate surface, and patent literature A photo-alignment method disclosed in 3, 4 and the like is known.

  For example, in Patent Document 3, a diamine compound having a cinnamic acid ester structure in the molecule is used. And the polyamic acid which is a polyimide precursor is synthesize | combined from the diamine compound and tetracarboxylic dianhydride, and the polyimide is formed from the polyamic acid, The photo-alignment vertical alignment type liquid crystal aligning film is obtained. . Polyimide is a high heat-resistant polymer material, has high reliability, and is a material suitable for use as a liquid crystal alignment film.

  The VA mode liquid crystal display device having the above-described configuration has the above-described excellent characteristics, and has come to be used for large-sized TVs and high-definition, high-quality mobile applications (display units of digital cameras and mobile phones). ing.

International Publication No. 2008/117615 Pamphlet Japanese Unexamined Patent Application Publication No. 2008-76950 Japan Special Table 2009-520702 Japanese Unexamined Patent Publication No. 2011-100099

VA mode liquid crystal display elements are required to further improve display quality in accordance with the expansion of applications to large-sized TVs and high-quality mobile devices.
As one of the problems for improving the display quality, improvement of display defects called burn-in is required.

Burn-in in a liquid crystal display element is one of display defects in which the same image is displayed for a long time and then the previous display is displayed as a shadow when the display is switched. Such display defects due to image sticking cause a reduction in display quality of the liquid crystal display element.
Display defects due to image sticking may occur in any mode of liquid crystal display element, although there is a difference in lightness of occurrence. However, there is a strong demand for improvement in VA mode liquid crystal display elements that are frequently used in applications that require particularly high display quality.

  An object of the present invention is to provide a liquid crystal aligning agent capable of forming a liquid crystal alignment film suitable for providing a liquid crystal display element having excellent display quality, a liquid crystal alignment film suitable for providing a liquid crystal display element having excellent display quality, and an excellent display. It is to provide a quality liquid crystal display element.

（Ｘ^１は、炭素数８〜２２の炭化水素基又は下記式（１Ａ）で示される基である。）

（Ｙ^１は単結合、−（ＣＨ_２）_ａ−（ａは１〜１５の整数である）、−Ｏ−、−ＣＨ_２Ｏ−、−ＣＯＯ−又はＯＣＯ−である。Ｙ^２は単結合又は−（ＣＨ_２）_ｂ−（ｂは１〜１５の整数である）である。Ｙ^３は単結合、−（ＣＨ_２）_ｃ−（ｃは１〜１５の整数である）、−Ｏ−、−ＣＨ_２Ｏ−、−ＣＯＯ−又は−ＯＣＯ−である。Ｙ^４はベンゼン環、シクロへキサン環及び複素環からなる群から選ばれる環状基（これらの環状基上の任意の水素原子は、炭素数１〜３のアルキル基、炭素数１〜３のアルコキシル基、炭素数１〜３のフッ素含有アルキル基、炭素数１〜３のフッ素含有アルコキシル基又はフッ素原子で置換されていてもよい。）、又は、ステロイド骨格を有する炭素数１２〜２５の有機基からなる群から選ばれる２価の有機基である。Ｙ^５はベンゼン環、シクロへキサン環及び複素環からなる群から選ばれる環状基（これらの環状基上の任意の水素原子は、炭素数１〜３のアルキル基、炭素数１〜３のアルコキシル基、炭素数１〜３のフッ素含有アルキル基、炭素数１〜３のフッ素含有アルコキシル基又はフッ素原子で置換されていてもよい。）である。Ｙ^６は炭素数１〜１８のアルキル基、炭素数１〜１８のフッ素含有アルキル基、炭素数１〜１８のアルコキシル基又は炭素数１〜１８のフッ素含有アルコキシル基である。ｎは０〜４の整数である。）The gist of the present invention is as follows.
(1) A polyimide precursor having a metabenzyl-type side chain structure and a side chain structure containing a photoreactive group, and at least one polymer selected from the group consisting of polyimides obtained by imidizing the polyimide precursor A liquid crystal aligning agent characterized by containing.
(2) The polyimide precursor includes a diamine component and a tetracarboxylic anhydride dianhydride including a first diamine compound represented by the following formula (1) and a second diamine compound having the photoreactive group. The liquid crystal aligning agent as described in said (1) which is polyamic acid obtained by making these react.

(X ¹ is a hydrocarbon group having 8 to 22 carbon atoms or a group represented by the following formula (1A).)

^{(Y 1} is a single _{bond, - (CH 2) a -} (a is an integer of _{1~15), - O -, -} CH 2 O -, - COO- or OCO- .Y ² is a single bond Or — (CH ₂ ) _b — (b is an integer of 1 to 15.) Y ³ is a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 15), —O—. -CH ₂ O-, -COO- or -OCO- Y ⁴ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a heterocyclic ring (any hydrogen atom on these cyclic groups is , An alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. Or selected from the group consisting of organic groups having 12 to 25 carbon atoms having a steroid skeleton. Valent organic group .Y ⁵ is a benzene ring, any hydrogen atom on the cyclic group (which cyclic group selected from the group consisting of hexane ring and heterocyclic cycloheteroalkyl is an alkyl group having 1 to 3 carbon atoms, Y ⁶ may be substituted with an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. It is a C1-C18 fluorine-containing alkyl group, a C1-C18 alkoxyl group, or a C1-C18 fluorine-containing alkoxyl group, n is an integer of 0-4. )

(3) The liquid crystal aligning agent according to the above (2), wherein the photoreactive group of the second diamine compound is a group that generates one of a photodimerization reaction and a photoisomerization reaction.
(4) The photoreactive group of the second diamine compound has at least one structure selected from the group consisting of a cinnamoyl structure, a coumarin structure, and a chalcone structure, as described in (2) or (3) above Liquid crystal aligning agent.

（上記式（２Ａ）及び上記式（２Ｂ）中、Ｒは、水素原子、炭素原子数１〜１０のアルキル基（ただし、その任意の水素原子はフッ素原子に置換されていてもよい。）、又は炭素原子数１〜１０のアルコキシ基（ただし、その任意の水素原子はフッ素原子に置換されていてもよい。）を表す。Ａ及びＢは、それぞれ独立に、単結合又は下記式に示すいずれかの環構造を表す。ただし、環構造中の任意の水素原子は、炭素数１〜１０のアルコキシ基で置換されていてもよい。Ｔ^１〜Ｔ^４は、それぞれ独立に、単結合、エーテル、エステル、アミド又はケトン結合を表す。Ｓは単結合又は炭素原子数１〜１０のアルキレン基を表す。）

(5) Any of the above (2) to (4), wherein the photoreactive group of the second diamine compound includes a structure represented by any of the following formula (2A) and the following formula (2B) Liquid crystal aligning agent as described in.

(In the above formula (2A) and the above formula (2B), R is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (however, any hydrogen atom may be substituted with a fluorine atom), Or an alkoxy group having 1 to 10 carbon atoms (wherein any hydrogen atom may be substituted with a fluorine atom), A and B are each independently a single bond or any of the following formulas: However, any hydrogen atom in the ring structure may be substituted with an alkoxy group having 1 to 10 carbon atoms, T ^{1 to} T ⁴ each independently represents a single bond or an ether. Represents an ester, amide or ketone bond, and S represents a single bond or an alkylene group having 1 to 10 carbon atoms.)

(6) The above (2), wherein the content of the metabenzyl-type diamine compound contained in the diamine component is 5 mol% to 50 mol%, and the content of the second diamine compound is 20 mol% to 95 mol%. Liquid crystal aligning agent in any one of-(5).
(7) The liquid crystal aligning agent in any one of said (1)-(6) whose content of the said polymer is 1-20 mass%.
(8) The liquid crystal aligning agent according to any one of (1) to (7), further including a crosslinking agent.
(9) A liquid crystal alignment film obtained using the liquid crystal aligning agent according to any one of (1) to (8).
(10) A liquid crystal display device having the liquid crystal alignment film according to (9).

  According to the present invention, a liquid crystal aligning agent capable of forming a liquid crystal alignment film suitable for providing a liquid crystal display element having excellent display quality, a liquid crystal alignment film suitable for providing a liquid crystal display element having excellent display quality, and an excellent display A high quality liquid crystal display element can be provided.

It is a graph which compares and shows the evaluation result of the liquid crystal cell of the Example of this invention.

The inventor examined the problem of burn-in of the VA mode liquid crystal display element, and found that the main factor was the fluctuation of the pretilt angle of the liquid crystal in the liquid crystal layer, which occurred when the AC voltage was continuously applied. .
Usually, the pretilt angle of the liquid crystal of the liquid crystal layer sandwiched between the pair of substrates is constant, and it is required that the fluctuation is small even when the liquid crystal is driven. In the VA mode liquid crystal display element, as described above, the pretilt angle of the liquid crystal is formed by, for example, an alignment-treated liquid crystal alignment film. At this time, in the VA mode liquid crystal display element, the pretilt angle formed between the liquid crystal alignment film and the liquid crystal may be changed by driving the liquid crystal by applying an alternating voltage for a long time.

  In that case, if the application of the AC voltage for a long time is performed in a partial region in the plane of the liquid crystal display element, the fluctuation of the pretilt angle occurs only in that region. On the other hand, in a region where no AC voltage is applied, such a change in the pretilt angle does not occur and the initial state is maintained. As a result, the drive characteristics of the liquid crystal may change between these regions. And the change of the drive characteristic of the liquid crystal in such a partial region may be visually recognized as burn-in of the VA mode liquid crystal display.

As a result of further studies, the present inventors have found that by specifying the structure of the liquid crystal alignment film used in the VA mode liquid crystal display element, it is effective in improving the above-described burn-in, and to complete the present invention. It came.
As described above, the VA mode liquid crystal display element can be configured using a liquid crystal alignment film. As the liquid crystal alignment film, a photo-alignment vertical alignment type liquid crystal alignment film can be used. In this photo-alignment vertical alignment type liquid crystal alignment film, it is not necessary to provide an electrode with an additional structure such as a slit structure. Moreover, the optical alignment process of a liquid crystal aligning film is possible, and the conventionally known rubbing process can be made unnecessary.

  The rubbing treatment, which is one of the orientation treatment methods, is an orientation treatment method in which the surface of the polyimide film is rubbed in a certain direction using a cloth. This rubbing treatment may generate dust by rubbing an organic film such as a polyimide film constituting the liquid crystal alignment film, and may cause unevenness of liquid crystal alignment by leaving scratches on the surface of the liquid crystal alignment film. Therefore, the liquid crystal alignment film preferably employs a photo-alignment process that does not require a rubbing process.

Therefore, the present inventor applied a photo-alignment vertical alignment type liquid crystal alignment film technology to the VA mode liquid crystal display element, and improved the image sticking of the VA mode liquid crystal display element due to the application of an AC voltage. To do.
The photo-alignment vertical alignment type liquid crystal alignment film of the VA mode liquid crystal display element is composed of a polymer in the same manner as a conventional liquid crystal alignment film. And it can form by apply | coating and film-forming using the liquid crystal aligning agent for forming the liquid crystal aligning film. In that case, a liquid crystal aligning agent is comprised including the polymer suitable for formation of a liquid crystal aligning film as a component. In the present invention, the polymer component of the liquid crystal aligning agent is used by copolymerizing a component for realizing vertical alignment of liquid crystal and a component having a photoreactive group for realizing photo-alignment treatment. It is formed. And the liquid crystal aligning agent can provide the photo-alignment vertical alignment-type liquid crystal display element suitable for a VA mode liquid crystal display element by including the formed polymer.

  The present inventor further specifies the structure of the liquid crystal alignment film, specifically, the structure of the polymer component contained in the liquid crystal aligning agent, thereby improving the photo-alignment property. A vertically aligned liquid crystal alignment film is provided. More specifically, the structure of the component for realizing the vertical alignment of the liquid crystal is specified, and the structure of the component having a photoreactive group for realizing the photo-alignment treatment is specified, and thus obtained. Specify the structure of the polymer. Thus, the liquid crystal aligning agent of the present invention provides a photoalignment type vertical alignment type liquid crystal alignment film and a liquid crystal display element containing a polymer having a specific structure and reduced image sticking due to application of an alternating voltage.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention includes a polymer whose structure is specified, and the polymer includes a metabenzyl-type side chain structure and a side chain structure including a photoreactive group that enables photoreaction processing. It is at least 1 type of polymer selected from the group which consists of the polyimide precursor which has, and the polyimide obtained by imidating it. In the present invention, examples of the polyimide precursor include polyamic acid and other polyamic acid esters. In particular, a polyamic acid that can easily form polyimide is preferable.

  As described above, the polyimide precursor contained in the liquid crystal aligning agent of the present invention and the polyimide obtained by imidizing the polyimide precursor enable metabenzyl type side chain structure and photoreaction treatment in the molecule. And a side chain structure containing a photoreactive group. The polyimide precursor can be synthesized by reacting a diamine component containing at least one diamine compound and a tetracarboxylic acid derivative component such as tetracarboxylic dianhydride according to a known method.

  As a method for obtaining a polyimide precursor having the above structure, a diamine compound having a structure for realizing a metabenzyl-type side chain structure in the molecule is used as the first diamine compound for the diamine component used for the synthesis. Can do. As the second diamine compound, a diamine compound having a photoreactive group that enables photo-alignment treatment in the molecule can be used. Then, by using these first diamine compound and second diamine compound, a polyimide precursor having a structure desired in the present invention and imidizing it by copolymerization reaction with a tetracarboxylic acid derivative component. A polyimide can be obtained.

  Below, diamine components, such as the 1st and 2nd diamine compound mentioned above, are demonstrated. That is, a diamine compound having a structure for realizing a metabenzyl-type side chain structure in the molecule (hereinafter also referred to as a metabenzyl-type diamine compound), which is suitable for obtaining a polyimide precursor having the structure as described above, and A diamine compound having a photoreactive group that enables photoalignment treatment in the molecule (hereinafter also referred to as a photoreactive diamine compound) and the like will be described. And a preferable tetracarboxylic acid derivative is demonstrated and the polyimide precursor in this invention, a polyimide, etc. are demonstrated as a component which is formed using them and can be contained in the liquid crystal aligning agent in this invention.

[Metabenzyl type diamine compound]
The metabenzyl type diamine compound in the present invention is represented by, for example, the following formula (1). That is, the metabenzyl-type diamine compound in the present invention has a benzene ring structure in which two amino groups are introduced at the 1-position and 3-position, and a benzyl group at the 5-position of the benzene ring, which is the meta-position of the amino group, respectively. The introduced compound is preferred.

  Since the metabenzyl type diamine compound in the present invention has a structure represented by the following formula (1), the liquid crystal aligning agent containing at least one polymer of a polyimide precursor and a polyimide synthesized using the compound has a vertical alignment property. The liquid crystal alignment film of the present invention can be formed. And the metabenzyl type diamine compound in this invention can be used with the photoreactive diamine compound explained in full detail later, and can form the polyimide precursor etc. of the desired structure mentioned above. The liquid crystal aligning agent of the present invention containing this polyimide precursor etc. controls the size of the pretilt angle of the liquid crystal of the liquid crystal display element, and at the same time, forms the liquid crystal aligning film of the present invention that improves the image sticking due to the application of an alternating voltage. can do.

式（１）中、Ｘ^１は、炭素数８〜２２の炭化水素基又は下記式（１Ａ）で示される基である。

In the formula (1), X ¹ is a hydrocarbon group having 8 to 22 carbon atoms or a group represented by the following formula (1A).

式（１Ａ）中、Ｙ^１は単結合、−（ＣＨ_２）_ａ−（ａは１〜１５の整数である）、−Ｏ−、−ＣＨ_２Ｏ−、−ＣＯＯ−又はＯＣＯ−である。Ｙ^２は単結合又は−（ＣＨ_２）_ｂ−（ｂは１〜１５の整数である）である。Ｙ^３は単結合、−（ＣＨ_２）_ｃ−（ｃは１〜１５の整数である）、−Ｏ−、−ＣＨ_２Ｏ−、−ＣＯＯ−又は−ＯＣＯ−である。Ｙ^４はベンゼン環、シクロへキサン環及び複素環からなる群から選ばれる環状基（これらの環状基上の任意の水素原子は、炭素数１〜３のアルキル基、炭素数１〜３のアルコキシル基、炭素数１〜３のフッ素含有アルキル基、炭素数１〜３のフッ素含有アルコキシル基又はフッ素原子で置換されていてもよい。）、又は、ステロイド骨格を有する炭素数１２〜２５の有機基からなる群から選ばれる２価の有機基である。Ｙ^５はベンゼン環、シクロへキサン環及び複素環からなる群から選ばれる環状基（これらの環状基上の任意の水素原子は、炭素数１〜３のアルキル基、炭素数１〜３のアルコキシル基、炭素数１〜３のフッ素含有アルキル基、炭素数１〜３のフッ素含有アルコキシル基又はフッ素原子で置換されていてもよい。）である。Ｙ^６は炭素数１〜１８のアルキル基、炭素数１〜１８のフッ素含有アルキル基、炭素数１〜１８のアルコキシル基又は炭素数１〜１８のフッ素含有アルコキシル基である。ｎは０〜４の整数である。

In Formula (1A), Y ¹ is a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 15), —O—, —CH ₂ O—, —COO—, or OCO—. Y ² is a single bond or — (CH ₂ ) _b — (b is an integer of 1 to 15). Y ³ is a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 15), —O—, —CH ₂ O—, —COO— or —OCO—. Y ⁴ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a heterocyclic ring (an arbitrary hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, an alkoxyl having 1 to 3 carbon atoms) Group, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom.), Or an organic group having 12 to 25 carbon atoms having a steroid skeleton A divalent organic group selected from the group consisting of Y ⁵ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a heterocyclic ring (an arbitrary hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, an alkoxyl having 1 to 3 carbon atoms) Or a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. Y ⁶ is an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 18 carbon atoms. n is an integer of 0-4.

In the above formula (1A), Y ¹ is a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 15), —O—, —CH ₂ O—, —COO—, or —OCO. -. Among them, a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 15), —O—, —CH ₂ O—, or —COO— facilitates the synthesis of the diamine compound. From the viewpoint of Also, a single _{bond, - (CH 2) a -} (a is an integer of 1 to 10.), - O -, - CH 2 O- or -COO- is more preferable.

In Formula (1A), Y ² is a single bond or — (CH ₂ ) _b — (b is an integer of 1 to 15). Among them, a single bond, or _{- (CH 2) b - (} . B is an integer of 1 to 10) are preferred.
In formula (1A), Y ³ is a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 15), —O—, —CH ₂ O—, —COO— or —OCO—. is there. Among them, a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 15), —O—, —CH ₂ O—, —COO— or —OCO— is a synthesis of the diamine compound. From the viewpoint of facilitating the process. Further, a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 10), —O—, —CH ₂ O—, —COO— or —OCO— is more preferable.

In Formula (1A), Y ⁴ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring, and a heterocyclic ring (an arbitrary hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, carbon Any one of an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, and a fluorine atom), or a steroid skeleton And a divalent organic group selected from the group consisting of organic groups having 12 to 25 carbon atoms. Among these, a divalent organic group having 12 to 25 carbon atoms and having a benzene ring, a cyclohexane ring, or a steroid skeleton is preferable.

In Formula (1A), Y ⁵ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring, and a heterocyclic ring, and any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms. Group, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom.
In said formula (1A), n is an integer of 0-4. Preferably, it is an integer of 0-2.

In Formula (1A), Y ⁶ is an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 18 carbon atoms. is there. Especially, it is preferable that they are a C1-C18 alkyl group, a C1-C10 fluorine-containing alkyl group, a C1-C18 alkoxyl group, or a C1-C10 fluorine-containing alkoxyl group. More preferably, it is a C1-C12 alkyl group or a C1-C12 alkoxyl group. More preferably, they are a C1-C9 alkyl group or a C1-C9 alkoxyl group.

Next, although the specific example of the diamine compound of the structure shown by the said Formula (1) is given, it is not limited to these examples.

In the formulas [1A-1] to [1A-3], R ₃ is —CH ₂ OCO—, —CH ₂ O— or —CH ₂ —, and R ₄ is a straight chain having 1 to 18 carbon atoms or A branched alkyl group, a linear or branched alkoxyl group having 1 to 18 carbon atoms, a linear or branched fluorine-containing alkyl group having 1 to 18 carbon atoms, or a linear or branched structure having 1 to 18 carbon atoms It is a fluorine-containing alkoxyl group.

In Formula [1A-4] and Formula [1A-5], R ₅ is —CH ₂ OCO—, —CH ₂ O— or CH ₂ —, and R ₆ is linear or branched having 1 to 18 carbon atoms. Alkyl group. )

In Formula [1A-6] and Formula [1A-7], R ₈ is a linear or branched alkyl group having 3 to 12 carbon atoms, and cis-trans isomerism of 1,4-cyclohexylene is trans. Isomer.

In the formula [1A-8], L ₄ is a linear or branched alkyl group having 3 to 20 carbon atoms which may be substituted with a fluorine atom, and L ₃ is a 1,4-cyclohexylene group or 1 , 4-phenylene group, L ₂ is an oxygen atom or COO- * (where a bond marked with “*” is bonded to A ₃ ), and L ₁ is an oxygen atom or COO— * (wherein , A bond marked with “*” binds to (CH ₂ ) a ₂ ). ). A ₁ is an integer of 0 or 1, a ₂ is an integer of ₂ to 10, and a ₃ is an integer of 0 or 1.

  When a polymer is synthesized using the diamine component containing the metabenzyl type diamine compound, the preferred content of the metabenzyl type diamine compound contained in the diamine component is not particularly limited, but in the diamine component, 5 mol% to 50 mol% is preferable, More preferably, it is 5 mol%-30 mol%.

[Photoreactive diamine compound]
The photoreactive diamine compound in the present invention has a photoreactive group. The photoreactive group of the photoreactive diamine compound in the present invention is preferably a group that generates either a photodimerization reaction or a photoisomerization reaction. By having such a photoreactive group, a liquid crystal alignment agent containing at least one polymer of a polyimide precursor and a polyimide synthesized using a photoreactive diamine compound forms a liquid crystal alignment film capable of photoalignment treatment. can do. And it can be used with the metabenzyl type diamine compound mentioned above, can form a polymer of desired structures, such as a polyimide precursor, and can form the vertical alignment type liquid crystal aligning film in which photo-alignment processing is possible.

  More specifically, the photoreactive diamine compound preferably has a photoreactive group having at least one structure selected from the group consisting of a cinnamoyl structure, a coumarin structure, and a chalcone structure. By having a photoreactive group having such a structure, a liquid crystal aligning agent containing at least one polymer of a polyimide precursor and a polyimide synthesized using a photoreactive diamine compound enables highly efficient photoalignment treatment. A liquid crystal alignment film having high liquid crystal alignment control performance can be formed.

上記式（２）中、Ｘ^２は置換基を表し、下記式（２Ａ）、又は下記式（２Ｂ)で示される構造の基である。The photoreactive diamine compound in the present invention is preferably a compound represented by the following formula (2).

In the above formula (2), X ² represents a substituent and is a group having a structure represented by the following formula (2A) or the following formula (2B).

In the above formula (2A) and the above formula (2B), R is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms (however, any hydrogen atom may be substituted with a fluorine atom), or An alkoxy group having 1 to 18 carbon atoms (however, an arbitrary hydrogen atom may be substituted with a fluorine atom). A and B each independently represent a single bond or any one of the ring structures represented by the following formulae. However, any hydrogen atom in the ring structure may be substituted with an alkoxy group having 1 to 10 carbon atoms. T ^{1 to} T ⁴ each independently represents a single bond, an ether, an ester, an amide, or a ketone bond. S represents a single bond or an alkylene group having 1 to 10 carbon atoms.

Hereinafter, preferable examples of the photoreactive diamine compound are shown.

Note that in _C n _{H 2n + 1} portion of the illustrated diamine compound in the above formula, n represents an integer of 0 to 18.
The following compounds are particularly preferable from the viewpoint of photoreactivity and the like.

In the C _n H _{2n + 1} portion of the particularly preferred diamine compound exemplified in the above formulas, n represents an integer of 0 to 18.

  In addition, the diamine component suitable for the formation of the polyimide precursor having the above-mentioned desired structure, which is contained in the liquid crystal aligning agent of the present invention, includes other diamines besides the above-mentioned benzyl type diamine compound and photoreactive diamine compound. It is also possible to contain a compound (sometimes referred to as other diamine compound). Other diamine compounds are not particularly limited, and examples thereof include alicyclic diamines, aromatic diamines, aromatic-aliphatic diamines, heterocyclic diamines, and aliphatic diamines. Specific examples are as follows.

Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4′-diaminodicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexylamine, isophorone Examples include diamines.
Examples of aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1,4-diamino. 2-methoxybenzene, 2,5-diamino-p-xylene, 1,3-diamino-4-chlorobenzene, 3,5-diaminobenzoic acid, 1,4-diamino-2,5-dichlorobenzene, 4,4 '-Diamino-1,2-diphenylethane, 4,4'-diamino-2,2'-dimethylbibenzyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane 4,4′-diamino-3,3′-dimethyldiphenylmethane, 2,2′-diaminostilbene, 4,4′-diaminostilbene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,5-bis (4-aminophenoxy) ) Benzoic acid, 4,4′-bis (4-aminophenoxy) bibenzyl, 2,2-bis [(4-aminophenoxy) methyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] Hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (3-aminophenyl) Enoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 1,1-bis (4-aminophenyl) cyclohexane, α, α′-bis (4-aminophenyl) -1,4- Diisopropylbenzene, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 ′ -Diaminodiphenylamine, 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrene, 1,6-diaminopyrene, 1,8- Diaminopyrene, 2,7-diaminofluorene, 1,3-bis (4-aminophenyl) tetramethyldisi Xanthine, benzidine, 2,2′-dimethylbenzidine, 1,2-bis (4-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,4-bis (4-aminophenyl) butane 1,5-bis (4-aminophenyl) pentane, 1,6-bis (4-aminophenyl) hexane, 1,7-bis (4-aminophenyl) heptane, 1,8-bis (4-aminophenyl) ) Octane, 1,9-bis (4-aminophenyl) nonane, 1,10-bis (4-aminophenyl) decane, 1,3-bis (4-aminophenoxy) propane, 1,4-bis (4- Aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,7-bis (4-aminophenoxy) heptane 1,8-bis (4-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,10-bis (4-aminophenoxy) decane, di (4-aminophenyl) propane-1, 3-dioate, di (4-aminophenyl) butane-1,4-dioate, di (4-aminophenyl) pentane-1,5-dioate, di (4-aminophenyl) hexane-1,6-dioate, di (4-aminophenyl) heptane-1,7-dioate, di (4-aminophenyl) octane-1,8-dioate, di (4-aminophenyl) nonane-1,9-dioate, di (4-aminophenyl) ) Decane-1,10-dioate, 1,3-bis [4- (4-aminophenoxy) phenoxy] propane, 1,4-bis [4- (4-aminopheno) Phenoxy] butane, 1,5-bis [4- (4-aminophenoxy) phenoxy] pentane, 1,6-bis [4- (4-aminophenoxy) phenoxy] hexane, 1,7-bis [4- (4-aminophenoxy) phenoxy] heptane, 1,8-bis [4- (4-aminophenoxy) phenoxy] octane, 1,9-bis [4- (4-aminophenoxy) phenoxy] nonane, 1,10- And bis [4- (4-aminophenoxy) phenoxy] decane.

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

  Examples of heterocyclic diamines include 2,6-diaminopyridine, 2,4-diaminopyridine, 2,4-diamino-1,3,5-triazine, 2,7-diaminodibenzofuran, 3,6-diamino. Examples thereof include carbazole, 2,4-diamino-6-isopropyl-1,3,5-triazine, 2,5-bis (4-aminophenyl) -1,3,4-oxadiazole.

  Examples of aliphatic diamines include 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane. 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,3-diamino-2,2-dimethylpropane, 1,6-diamino-2,5-dimethylhexane, 1,7 -Diamino-2,5-dimethylheptane, 1,7-diamino-4,4-dimethylheptane, 1,7-diamino-3-methylheptane, 1,9-diamino-5-methylheptane, 1,12-diamino Examples include dodecane, 1,18-diaminooctadecane, 1,2-bis (3-aminopropoxy) ethane and the like.

<Tetracarboxylic acid derivative>
The tetracarboxylic acid derivative used for the reaction with the diamine compound described above and for synthesizing the polyimide precursor or polyimide that can be contained in the liquid crystal aligning agent of the present invention is not particularly limited. Examples of preferable tetracarboxylic acid derivatives include tetracarboxylic dianhydrides frequently used for the synthesis of polyamic acids. Specific examples are shown below.

Examples of the tetracarboxylic dianhydride having an alicyclic structure or an aliphatic structure include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutane. Tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetra Carboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic Acid dianhydride, 3,4-dicarboxy-1-cyclohexyl succinic dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, 1, , 3,4-Butanetetracarboxylic dianhydride, bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetra Carboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride , Tricyclo [4.2.1.0 ^2,5 ] nonane-3,4,7,8-tetracarboxylic acid-3,4: 7,8-dianhydride, hexacyclo [6.6.0.1 ^{2 , 7} . 0 ^3,6 . 1 ^9,14 . 0 ^10,13] hexadecane -4,5,11,12- tetracarboxylic acid-4,5: 11,12-dianhydride, 4- (2,5-di-oxo-tetrahydrofuran-3-yl) -1,2 3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride and the like.

  As aromatic tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic acid Dianhydride, 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,3,3 ′, 4-benzophenonetetra Carboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride Products, 2,3,6,7-naphthalenetetracarboxylic dianhydride and the like.

When aromatic tetracarboxylic dianhydride is used in addition to the above-mentioned tetracarboxylic dianhydride having an alicyclic structure or aliphatic structure, the liquid crystal alignment is improved and the accumulated charge of the liquid crystal cell is reduced. This is preferable.
Tetracarboxylic dianhydride can be used alone or in combination of two or more depending on the liquid crystal alignment properties of the liquid crystal alignment film to be formed, such as voltage holding characteristics and accumulated charges.

[Polyamic acid]
As a polyimide precursor contained in the liquid crystal aligning agent of this invention, polyamic acid ester, polyamide, etc. other than polyamic acid are contained. In particular, it is preferable to select a polyamic acid that allows easy formation of polyimide.

  A polyamic acid preferable as a polyimide precursor contained in the liquid crystal aligning agent of the present invention is obtained by a reaction between a tetracarboxylic dianhydride which is a preferable tetracarboxylic acid derivative described above and a diamine component composed of the diamine compound described above. Can do. In obtaining the polyamic acid, a known synthesis method can be used. In general, tetracarboxylic dianhydride and a diamine component are reacted in an organic solvent. The reaction between the tetracarboxylic dianhydride and the diamine component is advantageous in that it proceeds relatively easily in an organic solvent and no by-product is generated.

The formed polyamic acid has a metabenzyl-type side chain structure with the above-described metabenzyl-type diamine compound and a side-chain structure containing a photoreactive group that enables photoreaction treatment with the photoreactive diamine compound.
In the metabenzyl side chain structure, the benzene ring structure of the metabenzyl type diamine compound of the formula (1) described above forms a part of the main chain structure of the polyamic acid, and the substituent X ¹ bonded thereto is the side chain structure. It becomes the structure which constitutes.

Moreover, it is preferable that the side chain structure containing the photoreactive group which enables photoreaction processing originates from the photoreactive diamine compound mentioned above, and contains either of the following side chain structures.

In the above formula (2A ′) and the above formula (2B ′), the broken line represents a bonding group to the main chain of the polyamic acid. R, A, B, T ¹ , T ² , T ³ , T ⁴ and S are synonymous with the above-described formulas (2A) and (2B). Specifically, R is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (however, any hydrogen atom may be substituted with a fluorine atom), or alkoxy having 1 to 10 carbon atoms. Represents a group (wherein any hydrogen atom may be substituted with a fluorine atom). A and B each independently represent a single bond or any one of the ring structures represented by the following formulae. However, any hydrogen atom in the ring structure may be substituted with an alkoxy group having 1 to 10 carbon atoms. T ^{1 to} T ⁴ each independently represents a single bond, an ether, an ester, an amide, or a ketone bond. S represents a single bond or an alkylene group having 1 to 10 carbon atoms. )

  The organic solvent used for the reaction between the tetracarboxylic dianhydride and the diamine component is not particularly limited as long as the generated polyamic acid dissolves. Specific examples are given below.

  N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide , Γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl Carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethyl Glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene Glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n- Hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, Ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropion , 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy -N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide and the like can be mentioned.

These organic solvents may be used alone or in combination. Further, even a solvent that does not dissolve the polyamic acid may be used by mixing with the above-mentioned organic solvent as long as the generated polyamic acid does not precipitate.
Further, since water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the produced polyamic acid, it is preferable to use an organic solvent that has been dehydrated and dried to the extent possible.

  When the tetracarboxylic dianhydride and the diamine component are reacted in an organic solvent, the solution in which the diamine component is dispersed or dissolved in the organic solvent is stirred, and the tetracarboxylic dianhydride is used as it is or in an organic solvent. A method of adding by dispersing or dissolving, a method of adding a diamine component to a solution in which tetracarboxylic dianhydride is dispersed or dissolved in an organic solvent, and alternately adding a tetracarboxylic dianhydride and a diamine component. Any of these methods may be used. Further, when the tetracarboxylic dianhydride or diamine component is composed of a plurality of types of compounds, they may be reacted in a premixed state, may be individually reacted sequentially, or may be further reacted individually. It is good also as a high molecular weight body by carrying out a mixing reaction.

  Although the polymerization temperature in that case can select the arbitrary temperature of -20 degreeC-150 degreeC, Preferably it is the range of -5 degreeC-100 degreeC. The reaction can be carried out at any concentration, but if the concentration is too low, it is difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring is difficult. Therefore, the total concentration of the tetracarboxylic dianhydride and the diamine component in the reaction solution is preferably 1% by mass to 50% by mass, more preferably 5% by mass to 30% by mass. The initial stage of the reaction is carried out at a high concentration, and then an organic solvent can be added.

  In the above reaction, the ratio of the total number of moles of tetracarboxylic dianhydride and the total number of moles of the diamine component is preferably 0.8 to 1.2, more preferably 0.9 to 1.1. . Similar to the normal polycondensation reaction, the molecular weight of the polyamic acid produced increases as the molar ratio approaches 1.0.

[Polyamic acid ester]
In addition, as a polyimide precursor of the component of the liquid crystal aligning agent of this invention, it is also possible to use polyamic acid ester and polyamide other than the polyamic acid mentioned above.
As a method for synthesizing a preferable polyamic acid ester, a method of reacting a tetracarboxylic acid diester dichloride with the above-mentioned preferable diamine component, or a method of reacting a tetracarboxylic acid diester with the above-mentioned preferable diamine component in the presence of a condensing agent, a base or the like. There is. By these methods, a polyamic acid ester which is a kind of polyimide precursor can be obtained. Alternatively, the polyamic acid ester can be obtained by polymerizing the polyamic acid in advance and esterifying the carboxylic acid in the amic acid using a polymer reaction.

  Specifically, tetracarboxylic acid diester dichloride and the above-mentioned preferred diamine component in the presence of a base and an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C., for 30 minutes to 24 hours, preferably Can be synthesized by reacting for 1 to 4 hours.

  As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferable because the reaction proceeds gently. The addition amount of the base is preferably 2 to 4 moles with respect to the tetracarboxylic acid diester dichloride, from the viewpoint of easy removal and easy obtaining of a high molecular weight product.

  When the condensation polymerization reaction is performed in the presence of a condensing agent, examples of the condensing agent include triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, and N, N′-carbonyldioxide. Imidazole, dimethoxy-1,3,5-triazinylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium tetrafluoroborate, O— (Benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate diphenyl, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) 4-methoxymorpholium chloride n- Hydrates can be used.

  In addition, in the method using a condensing agent, when a Lewis acid is added as an additive, the reaction proceeds efficiently. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The addition amount of the Lewis acid is preferably 0.1 to 1.0 mol times with respect to the tetracarboxylic acid diester.

As a solvent, the solvent used when polymerizing the above-mentioned tetracarboxylic dianhydride and a preferred diamine component to obtain a polyamic acid can be used. From the solubility of the monomer and the resulting polymer, N-methyl Use of 2-pyrrolidone, γ-butyrolactone, etc. is preferred. These solvents may be used alone or in combination of two or more. In order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for the synthesis of the polyamic acid ester is preferably dehydrated as much as possible.
The total concentration of the tetracarboxylic acid diester dichloride and the diamine component in the reaction solution is preferably 1% by mass to 30% by mass, and preferably 5% by mass from the viewpoint that polymer precipitation hardly occurs and a high molecular weight product is easily obtained. -20 mass% is more preferable.
Furthermore, the reaction is preferably performed in a nitrogen atmosphere to prevent outside air from being mixed.

〔polyamide〕
The polyamide preferable as the polyimide precursor described above can also be synthesized in the same manner as the polyamic acid ester described above.

[Polyimide]
As a polymer component contained in the liquid crystal aligning agent of the present invention, polyimide is a preferable polymer component in addition to the polyamic acid described above. The polyimide having a specific structure in the present invention can be obtained by dehydrating and ring-closing (imidizing) the polyamic acid described above.
In the polyimide contained in the liquid crystal aligning agent of the present invention, the dehydration cyclization rate (imidation rate) of the amic acid group is not necessarily 100%, and is 100% or less depending on the application and purpose. It can be adjusted arbitrarily.

Examples of the method for imidizing the polyamic acid include thermal imidization in which the polyamic acid solution is heated as it is, and catalytic imidization in which a catalyst is added to the polyamic acid solution.
The temperature at which the polyamic acid is thermally imidized in the solution is 100 ° C. to 400 ° C., preferably 120 ° C. to 250 ° C., and the method is preferably performed while removing water generated by the imidization reaction from the system.

  Catalytic imidation of polyamic acid can be performed by adding a basic catalyst and an acid anhydride to a polyamic acid solution and stirring at -20 ° C to 250 ° C, preferably 0 ° C to 180 ° C. The amount of the basic catalyst is 0.5 mol times to 30 mol times, preferably 2 mol times to 20 mol times of the amic acid group, and the amount of the acid anhydride is 1 mol times to 50 mol of the amic acid group. Double, preferably 3 to 30 mole times.

Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like. Among them, pyridine is preferable because it has an appropriate basicity for proceeding with the reaction.
Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Among them, use of acetic anhydride is preferable because purification after completion of the reaction is facilitated. The imidization rate by catalytic imidation can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[Recovery of polymer]
When recovering the produced polyamic acid, polyimide, etc. from the reaction solution of polyamic acid, polyimide, etc., which is a preferred polymer component obtained by the above reaction, the reaction solution is put into a poor solvent, and the polymer Can be precipitated. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and water. The polymer deposited in a poor solvent and precipitated can be recovered by filtration and then dried at normal temperature or under reduced pressure at room temperature or by heating.

  Moreover, when the polymer which carried out precipitation collection | recovery is re-dissolved in an organic solvent and the operation which carries out reprecipitation collection | recovery is repeated 2 to 10 times, the impurity in a polymer can be decreased. Examples of the poor solvent at this time include alcohols, ketones, hydrocarbons and the like, and it is preferable to use three or more kinds of poor solvents selected from these because purification efficiency is further improved.

  The molecular weight of the preferred polymer component polyamic acid and / or polyimide contained in the liquid crystal aligning agent of the present invention takes into consideration the strength of the resulting coating film, the workability during coating film formation, and the uniformity of the coating film. In this case, the weight average molecular weight measured by GPC (Gel Permeation Chromatography) method is preferably 2000 to 1000000, and more preferably 5000 to 100,000.

[Crosslinking agent]
The liquid crystal aligning agent of this invention can contain a crosslinking agent other than polymer components, such as a polyamic acid and / or a polyimide mentioned above. By including the cross-linking agent, the cross-linking reaction in the polymer component contained in the liquid crystal aligning agent proceeds, the stability of the pretilt angle formed between the obtained liquid crystal aligning film and the liquid crystal is increased, and the AC voltage is increased. Burn-in of the liquid crystal display element due to application can be reduced.

  The crosslinking agent is not particularly limited. The amount used is preferably 0.1 to 30 parts by mass, more preferably 1 part by mass with respect to 100 parts by mass of the polymer component such as the above-mentioned polyimide precursor contained in the liquid crystal aligning agent. ˜20 parts by mass. If the amount used is less than 0.1 parts by mass, the effect of crosslinking cannot be expected, and if it exceeds 30 parts by mass, the orientation of the liquid crystal may deteriorate.

As a preferable crosslinking agent, a compound having a structure in which a group represented by the formula (3A) is bonded to an aromatic ring (hereinafter also referred to as a specific compound) can be exemplified.

  In the above formula (3A), Z represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. In particular, when Z is a hydrogen atom, the liquid crystal alignment film can increase the pretilt angle of the liquid crystal while maintaining uniform alignment of the liquid crystal, and accelerate the discharge of charge accumulated in the liquid crystal display element. Is preferable.

The specific compound will be described in more detail. The specific compound has a structure in which a group represented by the above formula (3A) is bonded to an aromatic ring, but a group represented by the above formula (3A) (—CH ₂ —OZ group). ) Directly bonded to the aromatic ring facilitates the binding reaction between the polyamic acid and the polyimide, and also facilitates the self-reaction between specific compounds. This is presumed to be a factor that exhibits the above-described effects.

Among the specific compounds, at least one compound selected from the group consisting of a compound represented by the following formula (3-1) and a compound represented by the formula (3-2) is preferable.

In the above formulas (3-1) and (3-2), Z ₁ , Z ₂ , and Z ₃ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Y ₁ , Y ₂ And Y ₃ each independently represents an aromatic ring. Any hydrogen atom in the aromatic ring may be substituted with a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, or a vinyl group. G ₁ is a single bond, a divalent saturated hydrocarbon group having 1 to 10 carbon atoms, which may be bonded to all or part of it to form a cyclic structure, and any hydrogen atom is substituted with a fluorine atom Or —NH—, —N (CH ₃ ) —, or a group represented by the following formula (3B). t ₁ is an integer of 2 to 4, t ₂ and t ₃ are each independently an integer of 1 to 3, and a and b are each independently an integer of 1 to 3.

In formula (3B), P ₁ and P ₂ are each independently an alkylene group having 1 to 5 carbon atoms, and Q ₁ represents an aromatic ring.
Since the —CH ₂ —OZ ₁ group, —CH ₂ —OZ ₂ group and —CH ₂ —OZ ₃ group of the above formula (3-1) and the above formula (3-2) are directly bonded to the aromatic ring, Y ₁ , Y ₂ and Y ₃ are each independently an aromatic ring.

Specific examples of the aromatic ring include benzene ring, naphthalene ring, tetrahydronaphthalene ring, azulene ring, indene ring, fluorene ring, anthracene ring, phenanthrene ring, phenalene ring, pyrrole ring, imidazole ring, oxazole ring, thiazole ring, pyrazole Ring, pyridine ring, pyrimidine ring, quinoline ring, pyrazoline ring, isoquinoline ring, carbazole ring, purine ring, thiadiazole ring, pyridazine ring, triazine ring, pyrazolidine ring, triazole ring, pyrazine ring, benzimidazole ring, benzimidazole ring, thioline Ring, phenanthroline ring, indole ring, quinoxaline ring, benzothiazole ring, phenothiazine ring, acridine ring, oxazole ring and the like. Specific examples of more preferable aromatic rings include benzene ring, naphthalene ring, fluorene ring, anthracene ring, pyrrole ring, imidazole ring, pyrazole ring, pyridine ring, pyrimidine ring, quinoline ring, isoquinoline ring, carbazole ring, pyridazine ring, pyrazine. Ring, benzimidazole ring, benzimidazole ring, indole ring, quinoxaline ring, acridine ring and the like. More preferred is a benzene ring, naphthalene ring, pyridine ring or carbazole ring, and most preferred is a benzene ring or pyridine ring.
In addition, the hydrogen atom of these aromatic rings may be substituted with a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, or a vinyl group.

T ₂ and t ₃ in the above formula (3-2) are more preferably integers of 1 or 2. Moreover, a and b are more preferably 1 or 2.
X ₁ in the above formula (3-1) and X ₂ and X ₃ in the formula (3-2) are each independently selected from the group consisting of a hydrogen atom, CH ₃ , C ₂ H ₅ and C ₃ H _7. One group is preferred, and the smaller the number of carbons, the better the bond reaction with polyimide and polyamic acid, or the easier the self-reaction between specific compounds. On the other hand, when the number of carbon atoms increases, the reactivity of the —CH ₂ —OZ ₁ group, —CH ₂ —OZ ₂ group, and —CH ₂ —OZ ₃ group decreases, so that the storage stability of the solution containing the specific compound is improved. Increase. In particular, when Z ₁ in the above formula (3-1) and Z ₂ and Z ₃ in the above formula (3-2) are hydrogen atoms, the pretilt angle of the liquid crystal is increased while maintaining uniform liquid crystal orientation. This is preferable because the charge stored in the liquid crystal display element can be discharged quickly.

Z ₁ in the above formula (3-2) is a divalent saturated hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, which may be bonded to all or part thereof to form a cyclic structure. In this case, an arbitrary hydrogen atom contained therein may be substituted with a fluorine atom.
Examples of G ₁ include an alkylene group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, a combination of an alkylene group and an alicyclic hydrocarbon group, and 1 carbon atom. -10 groups. In addition, a group in which any hydrogen atom of the above-described group is substituted with a fluorine atom is exemplified.

Q ₁ in the higher formula (3B) is an aromatic ring, and specific examples thereof include a benzene ring, naphthalene ring, tetrahydronaphthalene ring, azulene ring, indene ring, fluorene ring, anthracene ring, phenanthrene ring, phenalene ring, Pyrrole ring, imidazole ring, oxazole ring, thiazole ring, pyrazole ring, pyridine ring, pyrimidine ring, quinoline ring, pyrazoline ring, isoquinoline ring, carbazole ring, purine ring, thiadiazole ring, pyridazine ring, triazine ring, pyrazolidine ring, triazole ring , Pyrazine ring, benzimidazole ring, benzimidazole ring, thionoline ring, phenanthroline ring, indole ring, quinoxaline ring, benzothiazole ring, phenothiazine ring, acridine ring, oxazole ring and the like. Specific examples of more preferable aromatic rings include benzene ring, naphthalene ring, fluorene ring, anthracene ring, pyrrole ring, imidazole ring, pyrazole ring, pyridine ring, pyrimidine ring, quinoline ring, isoquinoline ring, carbazole ring, pyridazine ring, pyrazine. Ring, benzimidazole ring, benzimidazole ring, indole ring, quinoxaline ring, acridine ring and the like. More preferably, a benzene ring, a naphthalene ring, a pyridine ring, a carbazole ring, a fluorene ring, etc. are mentioned.

  In the liquid crystal aligning agent of this invention, it is also possible to use the at least 1 type compound chosen from the group which consists of said Formula (3-1) and said Formula (3-2) for the preparation.

  Specific examples of the specific compound used in the liquid crystal aligning agent of the present invention include [P1] to [P45], but are not limited thereto.

  Among the specific compounds described above, compounds represented by [P15], [P17], [P19], [P29], [P31], or [P41] are preferable, and among them, [P15], [P17], The compound represented by [P29], [P31], or [P41] is more preferable.

(Preparation of liquid crystal aligning agent)
As described above, the liquid crystal aligning agent of the present invention includes a metabenzyl-type side chain structure such as a polyimide precursor and a polyimide obtained by imidizing the polyimide precursor, and a photoreactive group that enables a photoreactive treatment. A polymer component having a specific structure having a side chain structure is contained. And the liquid crystal aligning agent in this invention can contain a crosslinking agent.

  It is preferably prepared as a coating solution so as to be suitable for forming the liquid crystal alignment film of the present invention. That is, the liquid crystal aligning agent of the present invention is preferably prepared as a solution in which a resin component for forming a resin film is dissolved in an organic solvent. Here, the resin component is a resin component including the polymer component described above. In that case, the content of the resin component is preferably 1% by mass to 20% by mass, more preferably 3% by mass to 15% by mass, and particularly preferably 3% by mass to 10% by mass.

In the liquid crystal aligning agent of the present invention, the above-described resin component may be a polymer having the specific structure described above, or other polymers may be mixed. In that case, content of the other polymer in a resin component is 0.5 mass%-15 mass%, Preferably they are 1 mass%-10 mass%.
Such other polymers are composed of, for example, polyamic acid, polyimide, and the like, such as a metabenzyl type side chain structure, or a polymer that does not have a side chain structure including a photoreactive group that enables photoreaction treatment. Can be mentioned.

  The organic solvent used in the liquid crystal aligning agent of the present invention is not particularly limited as long as it dissolves the resin component and dissolves the crosslinking agent contained when necessary. Specific examples are given below.

  N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethylsulfoxide, tetramethylurea, pyridine, Dimethylsulfone, hexamethylsulfoxide, γ-butyrolactone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide, 1,3 -Dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, 4-hydroxy-4 Methyl-2-pentanone and the like. These may be used alone or in combination. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyllactone is preferable as the organic solvent used in the liquid crystal aligning agent of the present invention.

The liquid crystal aligning agent of this invention may contain components other than above-described components, such as a polymer of a specific structure. Examples thereof include solvents and compounds that improve the film thickness uniformity and surface smoothness when a liquid crystal aligning agent is applied, and compounds that improve the adhesion between the liquid crystal aligning film and the substrate.
Specific examples of the solvent (poor solvent) that improves the uniformity of the film thickness and the surface smoothness include the following.

  For example, isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoacetate Isopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, propylene Glycol monobutyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexane Xene, propyl ether, dihexyl ether, 1-hexanol, -Hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, 3-methoxy Methyl propionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2 -Propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether -2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl lactate Examples thereof include solvents having a low surface tension such as esters and lactyl isoamyl esters.

  These poor solvents may be used alone or in combination. When using the solvent as described above, it is preferably 5% by mass to 80% by mass of the total solvent, more preferably so as not to significantly reduce the solubility of the entire solvent contained in the liquid crystal aligning agent. It is 20 mass%-60 mass%. The poor solvent used in the liquid crystal aligning agent of the present invention is preferably butyl cellosolve, propylene glycol monobutyl ether, or dipropylene glycol monomethyl ether.

Examples of the compound that improves film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants.
Specifically, for example, Ftop (registered trademark) 301, EF303, EF352 (manufactured by Tochem Products), MegaFac (registered trademark) F171, F173, R-30 (manufactured by DIC), Florard FC430, FC431 ( Sumitomo 3M), Asahi Guard (registered trademark) AG710 (manufactured by Asahi Glass), Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by AGC Seimi Chemical). . The use ratio of these surfactants is preferably 0.01 parts by weight to 2 parts by weight, more preferably 0.01 parts by weight to 1 part by weight with respect to 100 parts by weight of the resin component contained in the liquid crystal aligning agent. Part.

Specific examples of the compound that improves the adhesion between the liquid crystal alignment film and the substrate include the following functional silane-containing compounds and epoxy group-containing compounds.
For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-to Ethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltri Methoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-amino Propyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether , Polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetra Glycidyl-2,4-hexanediol, N, N, N ′, N ′,-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N Examples include ', N',-tetraglycidyl-4,4'-diaminodiphenylmethane.

  In the liquid crystal aligning agent of the present invention, in addition to those described above, a dielectric or conductive material may be used for the purpose of changing electrical characteristics such as dielectric constant and conductivity of the liquid crystal aligning film as long as the effects of the present invention are not impaired. A crosslinkable compound may be added for the purpose of increasing the hardness and density of the substance and, further, the liquid crystal alignment film.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal aligning agent of the present invention described above can be applied to other methods by applying and baking on a substrate in the same manner as the liquid crystal aligning agent for forming a liquid crystal aligning film made of conventional polyimide. The liquid crystal alignment film in the present invention can be formed. Then, by performing a photo-alignment treatment by light irradiation, alignment control ability can be imparted and used for manufacturing a liquid crystal display element.

  As a substrate used when the liquid crystal aligning agent of the present invention is applied to form a liquid crystal alignment film, a substrate having high transparency is preferably used when the manufactured liquid crystal display element is a transmission type. In that case, there is no particular limitation, and a glass substrate or a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used. In order to drive the liquid crystal in the liquid crystal display element, it is preferable to use a substrate on which a transparent electrode such as an ITO (Indium Tin Oxide) electrode is formed from the viewpoint of simplifying the manufacturing process. In the reflective liquid crystal display element, an opaque object such as a silicon wafer can be used as long as it is only on one substrate, and the electrode in this case can be made of a material that reflects light such as aluminum.

  In formation of the liquid crystal aligning film of this invention, the coating method of the liquid crystal aligning agent in this invention is not specifically limited. As the application method of the liquid crystal aligning agent, industrially, screen printing, offset printing, flexographic printing, ink jet, and the like are common. As other coating methods, there are methods using a dip, a roll coater, a slit coater, a spinner and the like, and these may be used according to the purpose.

  Firing after applying the liquid crystal aligning agent of the present invention on the substrate is performed at 50 ° C. to 300 ° C., preferably 80 ° C. to 250 ° C. by a heating means such as a hot plate, for example, by evaporating the solvent which is an organic solvent. Thus, a coating film can be formed. When the thickness of the coating film formed after baking is too thick, it is disadvantageous in terms of power consumption when used for a liquid crystal display element, and when it is too thin, the reliability of the liquid crystal display element may be lowered. Therefore, the thickness of the coating film after baking is preferably 5 nm to 300 nm, more preferably 10 nm to 100 nm.

  When the liquid crystal is vertically aligned while forming a pretilt angle, the baked coating film is treated by irradiation with polarized ultraviolet rays. That is, a photo-alignment process is performed. In addition, the liquid crystal alignment film in the present invention can be imparted with alignment control ability, in particular, a pretilt angle can be formed by rubbing treatment.

  The liquid crystal display element of the present invention, after obtaining the substrate with the liquid crystal alignment film on which the liquid crystal alignment film of the present invention is formed from the liquid crystal aligning agent of the present invention by the above-described method, It is a liquid crystal display element. In the present invention, a VA mode liquid crystal display element can be provided.

  To give an example of liquid crystal cell preparation, a pair of substrates on which the liquid crystal alignment film of the present invention is formed is prepared, spacers are scattered on the liquid crystal alignment film of one substrate, and the liquid crystal alignment film surface is on the inside. Then, the other substrate is bonded, the liquid crystal is injected under reduced pressure and sealed, or the liquid crystal is dropped on the liquid crystal alignment film surface on which the spacers are dispersed, and then the substrate is bonded and sealed, Etc. can be illustrated. The spacer diameter at this time is preferably 1 μm to 30 μm, more preferably 2 μm to 10 μm. This spacer diameter determines the distance between the pair of substrates that sandwich the liquid crystal layer, that is, the thickness of the liquid crystal layer.

  As described above, the liquid crystal display element produced using the liquid crystal alignment treatment agent of the present invention has excellent reliability, excellent display quality, and suitable for use in a large-screen, high-definition liquid crystal television. it can.

  The following examples further illustrate the present invention. The present invention is not construed as being limited to these. The main compounds used in the synthesis examples and examples, and the abbreviations and structures thereof are as follows.

(Tetracarboxylic dianhydride)
BODA: Bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride

(Diamine)
DA-1: Compound represented by the following formula

DA-2: Compound represented by the following formula

DA-3: Compound represented by the following formula

DA-4: Compound represented by the following formula

DA-5: Compound represented by the following formula

DA-6: Compound represented by the following formula

DA-7: Compound represented by the following formula

(Crosslinking agent)
TM-BIP: 2,2′-bis (4-hydroxy-3,5-dihydroxymethylphenyl) propane (solvent)
NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve

Next, methods for measuring molecular weight and measuring the imidization ratio of polyimide will be described.
[Molecular weight measurement]
The molecular weight of the polyimide was measured as follows using a normal temperature gel permeation chromatography (GPC) apparatus (SSC-7200) manufactured by Senshu Scientific Co., Ltd. and a column (KD-803, KD-805) manufactured by Shodex.
Column temperature: 50 ° C
Eluent: N, N′-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H 2 O) 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran ( THF) is 10 ml / L)
Flow rate: 1.0 ml / min Standard sample for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: about 9000000, 150,000, 100,000, 30000) manufactured by Tosoh Corporation and polyethylene glycol (molecular weight: about 12000, 4000, 1000) manufactured by Polymer Laboratories .

[Imidation rate measurement]
The imidation ratio of polyimide was measured as follows. Add 20 mg of polyimide powder to an NMR sample tube (NMR sampling tube standard φ5 manufactured by Kusano Kagaku Co., Ltd.), add 1.0 ml of deuterated dimethyl sulfoxide (DMSO-d ₆ , 0.05% TMS mixture), and apply ultrasonic waves. To dissolve completely. 500 MHz proton NMR was measured for this solution with the NMR measuring device by the JEOL datum company (JNW-ECA500). The imidation rate is determined based on protons derived from structures that do not change before and after imidation as reference protons, and the peak integrated value of these protons and proton peaks derived from NH groups of amic acid appearing near 9.5 to 10.0 ppm. Using the integrated value, the following formula was used. In the following formula, x is the proton peak integrated value derived from the NH group of the amic acid, y is the peak integrated value of the reference proton, and α is the NH group of the amic acid in the case of polyamic acid (imidation rate is 0%). It is the number ratio of the reference proton to one proton.
[Equation 1]
Imidation ratio (%) = (1−α · x / y) × 100

(Synthesis Example 1)
BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), DA-1 (1.04 g, 2.4 mmol) were dissolved in NMP (29.27 g) at 80 ° C. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.76 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42g) and diluting to 6 mass%, acetic anhydride (4.22g) and pyridine (2.73g) were added as an imidation catalyst, and it was made to react at 80 degreeC for 4 hours. This reaction solution was poured into methanol (520 ml), and the resulting precipitate was separated by filtration. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (A1). The imidation ratio of this polyimide was 60%, the number average molecular weight was 10,000, and the weight average molecular weight was 35000.
NMP (44.0 g) was added to the obtained polyimide powder (A1) (6.0 g), and the mixture was stirred and dissolved at 50 ° C. for 12 hours. BCS (50.0g) was added to this solution, and the liquid crystal aligning agent (B1) was obtained by stirring at 50 degreeC for 5 hours.

(Synthesis Example 2)
BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), DA-3 (1.08 g, 2.4 mmol) were dissolved in NMP (29.37 g) at 80 ° C. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.79 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42g) and diluting to 6 mass%, acetic anhydride (4.21g) and pyridine (2.72g) were added as an imidation catalyst, and it was made to react at 80 degreeC for 4 hours. This reaction solution was poured into methanol (520 ml), and the resulting precipitate was separated by filtration. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (A2). The imidation ratio of this polyimide was 60%, the number average molecular weight was 12000, and the weight average molecular weight was 38000.
NMP (44.0 g) was added to the obtained polyimide powder (A2) (6.0 g), and the mixture was dissolved by stirring at 50 ° C. for 12 hours. BCS (50.0 g) was added to this solution, and the liquid crystal aligning agent (B2) was obtained by stirring at 50 degreeC for 5 hours. The liquid crystal aligning agent (B2) is a liquid crystal aligning agent containing a polyimide having the above-described metabenzyl-type side chain structure and a side chain structure containing a photoreactive group that enables photoreaction treatment.

(Synthesis Example 3)
0.03 g (5% by mass with respect to the solid content) of the crosslinking agent TM-BIP is added to 10.0 g of the liquid crystal aligning agent (B2), and the mixture is stirred and dissolved at room temperature for 3 hours to obtain the liquid crystal aligning agent (B3). Was prepared.
(Synthesis Example 4)
0.06 g (10% by mass with respect to the solid content) of the crosslinking agent TM-BIP is added to 10.0 g of the liquid crystal aligning agent (B2), and dissolved by stirring at room temperature for 3 hours. Was prepared.

(Synthesis Example 5)
BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), DA-4 (0.91 g, 2.4 mmol) were dissolved in NMP (28.88 g) at 80 ° C. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.63 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42g) and diluting to 6 mass%, acetic anhydride (4.28g) and pyridine (2.76g) were added as an imidation catalyst, and it was made to react at 80 degreeC for 4 hours. This reaction solution was poured into methanol (520 ml), and the resulting precipitate was separated by filtration. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (A3). The imidation ratio of this polyimide was 60%, the number average molecular weight was 10,000, and the weight average molecular weight was 35000.
NMP (44.0 g) was added to the obtained polyimide powder (A3) (6.0 g), and the mixture was dissolved by stirring at 50 ° C. for 12 hours. BCS (50.0g) was added to this solution, and the liquid crystal aligning agent (B5) was obtained by stirring at 50 degreeC for 5 hours.

(Synthesis Example 6)
BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), DA-6 (0.95 g, 2.4 mmol) were dissolved in NMP (28.98 g) at 80 ° C. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.66 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42g) and diluting to 6 mass%, acetic anhydride (4.26g) and pyridine (2.75g) were added as an imidation catalyst, and it was made to react at 80 degreeC for 4 hours. This reaction solution was poured into methanol (520 ml), and the resulting precipitate was separated by filtration. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (A4). The imidation ratio of this polyimide was 60%, the number average molecular weight was 12000, and the weight average molecular weight was 38000.
NMP (44.0 g) was added to the obtained polyimide powder (A4) (6.0 g), and the mixture was dissolved by stirring at 50 ° C. for 12 hours. BCS (50.0 g) was added to this solution, and the liquid crystal aligning agent (B6) was obtained by stirring at 50 degreeC for 5 hours. The liquid crystal aligning agent (B6) is a liquid crystal aligning agent containing a polyimide having the above-described metabenzyl-type side chain structure and a side chain structure containing a photoreactive group that enables photoreaction treatment.

(Synthesis Example 7)
0.03 g (5% by mass with respect to the solid content) of the crosslinking agent TM-BIP is added to 10.0 g of the liquid crystal aligning agent (B6), and dissolved by stirring at room temperature for 3 hours. Was prepared.
(Synthesis Example 8)
0.06 g (10% by mass with respect to the solid content) of the crosslinking agent TM-BIP is added to 10.0 g of the liquid crystal aligning agent (B6), and dissolved by stirring at room temperature for 3 hours. Was prepared.

(Synthesis Example 9)
BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), DA-2 (1.11 g, 2.4 mmol) were dissolved in NMP (29.47 g) at 80 ° C. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.82 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42g) and diluting to 6 mass%, acetic anhydride (4.19g) and pyridine (2.71g) were added as an imidation catalyst, and it was made to react at 80 degreeC for 4 hours. This reaction solution was poured into methanol (520 ml), and the resulting precipitate was separated by filtration. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (A5). The imidation ratio of this polyimide was 60%, the number average molecular weight was 12000, and the weight average molecular weight was 38000.
NMP (44.0 g) was added to the obtained polyimide powder (A5) (6.0 g), and the mixture was dissolved by stirring at 50 ° C. for 12 hours. BCS (50.0g) was added to this solution, and the liquid crystal aligning agent (B9) was obtained by stirring at 50 degreeC for 5 hours.

(Synthesis Example 10)
BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), DA-5 (0.98 g, 2.4 mmol) were dissolved in NMP (29.08 g) at 80 ° C. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.69 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42g) and diluting to 6 mass%, acetic anhydride (4.25g) and pyridine (2.74g) were added as an imidation catalyst, and it was made to react at 80 degreeC for 4 hours. This reaction solution was poured into methanol (520 ml), and the resulting precipitate was separated by filtration. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (A6). The imidation ratio of this polyimide was 60%, the number average molecular weight was 12000, and the weight average molecular weight was 38000.
NMP (44.0 g) was added to the obtained polyimide powder (A6) (6.0 g), and the mixture was dissolved by stirring at 50 ° C. for 12 hours. BCS (50.0 g) was added to this solution, and the liquid crystal aligning agent (B10) was obtained by stirring at 50 degreeC for 5 hours.

<Formation of liquid crystal alignment film and production of liquid crystal cell>
(Comparative Example 1)
The liquid crystal aligning agent (B1) obtained in Synthesis Example 1 is spin-coated on the ITO surface of a glass substrate with a transparent electrode made of an ITO film, dried for 90 seconds on an 80 ° C. hot plate, and then heated at 200 ° C. Baking was performed for 30 minutes in an oven to form a liquid crystal alignment film having a thickness of 100 nm.
The substrate was subjected to photo-alignment treatment by irradiating 20 mJ of 313 nm linearly polarized light UV having an irradiation intensity of 10.0 mW / cm ⁻² . The direction of the incident light was inclined by 40 ° with respect to the normal direction of the substrate. The linearly polarized light UV was prepared by passing a 313 nm band pass filter through the ultraviolet light of a high pressure mercury lamp and then passing it through a 313 nm polarizing plate.

After spraying 6 μm bead spacers on the liquid crystal alignment film of one of the two substrates, a sealant (solvent type thermosetting epoxy resin) was printed thereon. Next, the surface of the other substrate on which the liquid crystal alignment film was formed was faced inward and bonded to the previous substrate, and then the sealing agent was cured to produce an empty cell. Liquid crystal MLC-6608 (trade name, manufactured by Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method to produce a liquid crystal cell.
The pretilt angle of the obtained liquid crystal cell was measured by the following method.
Thereafter, an alternating voltage (AC) of 30 Hz, 20 V _p-p was applied to the liquid crystal cell at room temperature for 168 hours (AC drive). Thereafter, the pretilt angle was measured again, and the change in pretilt angle (pretilt angle change) before and after AC driving was evaluated. The results are shown in Table 1.

[Pretilt angle measurement]
The pretilt angle of the liquid crystal cell was measured by the Mueller matrix method using “Axo Scan” manufactured by Axo Metrix.

Example 1
Except for using the liquid crystal aligning agent (B2) in place of the liquid crystal aligning agent (B1), the same operation as in Comparative Example 1 was performed to form a liquid crystal aligning film, and the AC drive of the liquid crystal cell manufactured using the same The change of the pretilt angle before and after was evaluated.

(Example 2)
Except for using the liquid crystal aligning agent (B3) in place of the liquid crystal aligning agent (B1), the same operation as in Comparative Example 1 was performed to form a liquid crystal aligning film, and the AC drive of the liquid crystal cell produced using the liquid crystal aligning film The pretilt angle change before and after was evaluated.

(Example 3)
Except for using the liquid crystal aligning agent (B4) in place of the liquid crystal aligning agent (B1), the same operation as in Comparative Example 1 was performed to form a liquid crystal aligning film, and the AC drive of the liquid crystal cell manufactured using the same The pretilt angle change before and after was evaluated.

(Comparative Example 3)
Except for using the liquid crystal aligning agent (B5) in place of the liquid crystal aligning agent (B1), the same operation as in Comparative Example 1 was performed to form a liquid crystal aligning film, and the AC driving of the liquid crystal cell produced using the liquid crystal aligning film The pretilt angle change before and after was evaluated.

Example 4
Except for using the liquid crystal aligning agent (B6) in place of the liquid crystal aligning agent (B1), the same operation as in Comparative Example 1 was performed to form a liquid crystal aligning film, and the AC drive of the liquid crystal cell manufactured using the same The pretilt angle change before and after was evaluated.

(Example 5)
Except for using the liquid crystal aligning agent (B7) instead of the liquid crystal aligning agent (B1), the same operation as in Comparative Example 1 was performed to form a liquid crystal aligning film, and the AC driving of the liquid crystal cell manufactured using the same The pretilt angle change before and after was evaluated.

(Example 6)
Except for using the liquid crystal aligning agent (B8) instead of the liquid crystal aligning agent (B1), the same operation as in Comparative Example 1 was performed to form a liquid crystal aligning film, and the AC driving of the liquid crystal cell manufactured using the same The pretilt angle change before and after was evaluated.

(Comparative Example 2)
Except for using the liquid crystal aligning agent (B9) in place of the liquid crystal aligning agent (B1), the same operation as in Comparative Example 1 was performed to form a liquid crystal aligning film, and the AC drive of the liquid crystal cell produced using the liquid crystal aligning film The pretilt angle change before and after was evaluated.

(Comparative Example 4)
Except for using the liquid crystal aligning agent (B10) instead of the liquid crystal aligning agent (B1), the same operation as in Comparative Example 1 was performed to form a liquid crystal aligning film, and the AC driving of the liquid crystal cell manufactured using the same The pretilt angle change before and after was evaluated.

The evaluation results of Examples 1 to 6 and Comparative Examples 1 to 4 are summarized in Table 1 and FIG.
FIG. 1 is a graph showing comparison results of the evaluation results of the liquid crystal cell of the example of the present invention.

  The liquid crystal cell produced in Example 1 and Example 4 is a liquid crystal alignment containing a polyimide having the above-described metabenzyl-type side chain structure and a side chain structure containing a photoreactive group capable of photoreactive treatment. A liquid crystal cell having a liquid crystal alignment film formed using the agent (B2) and the liquid crystal alignment agent (B6) is obtained. In addition, the liquid crystal cells produced in Examples 2 and 3 and Examples 5 and 6 have the above-described metabenzyl-type side chain structure and a side chain containing a photoreactive group that enables photoreactive treatment. A liquid crystal having a liquid crystal alignment film formed using a liquid crystal aligning agent (B3), a liquid crystal aligning agent (B4), a liquid crystal aligning agent (B7) and a liquid crystal aligning agent (B7) containing a polyimide having a structure and a crosslinking agent. Become a cell.

  For example, the liquid crystal cells produced in Comparative Example 1 and Comparative Example 3 contain a polyimide having an ortho ether type side chain structure and a side chain structure containing a photoreactive group that enables photoreaction treatment. It becomes a liquid crystal cell which has the liquid crystal aligning film formed using the liquid crystal aligning agent (B1) and the liquid crystal aligning agent (B5).

  As shown in Table 1 and FIG. 1, in the liquid crystal cells of Example 1 and Example 4, the change in the pretilt angle by AC driving (in Table 1, the change in the pretilt angle compared to Comparative Example 1 and Comparative Example 3). (Shown as (°)) was confirmed to be suppressed.

  In addition, in the liquid crystal cells of Example 2, Example 3, Example 5 and Example 6, it was confirmed that the change in the pretilt angle due to AC driving is further suppressed by the effect of the crosslinking agent contained in the liquid crystal aligning agent. It was done.

  As mentioned above, the liquid crystal aligning film obtained from the liquid crystal aligning agent containing the polyimide which has the metabenzyl type side chain structure of a present Example and the side chain structure containing the photoreactive group which enables photoreaction processing was used. It has been found that the VA mode liquid crystal display element can reduce image sticking due to application of an alternating voltage. That is, a liquid crystal alignment film obtained from a liquid crystal aligning agent containing a polyimide having a metabenzyl-type side chain structure of this example and a side chain structure containing a photoreactive group capable of photoreaction treatment is an alternating voltage. It has been found that the present invention is suitable for providing a VA mode liquid crystal display element in which image sticking due to application of is reduced.

  The liquid crystal alignment agent of the present invention can provide a vertical alignment liquid crystal alignment film that can be photo-aligned and is effective in improving display defects such as image sticking. Therefore, it is possible to manufacture a VA mode liquid crystal display element with high productivity and excellent display quality, and a liquid crystal display for a portable information terminal such as a large-sized liquid crystal TV or a smartphone displaying high-definition images. It can use suitably for manufacture of an element. That is, the liquid crystal surface element of the present invention having the liquid crystal alignment film of the present invention constitutes a VA mode liquid crystal display element of high display quality, and is a portable information terminal such as a large TV or a smartphone displaying a high-definition image. It can be suitably used as a display element.

  The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2012-2224017 filed on Oct. 9, 2012 are cited herein as disclosure of the specification of the present invention. Incorporated.

Claims (6)

A first diamine compound represented by the following formula (1) and a second diamine compound having a photoreactive group including a structure represented by any of the following formula (2A) and the following formula (2B): It contains at least one polymer selected from the group consisting of a polyamic acid obtained by reacting a diamine component and a tetracarboxylic acid dianhydride component, and a polyimide obtained by imidizing the polyamic acid. A liquid crystal aligning agent characterized by that.

(X ¹ is a hydrocarbon group having 8 to 22 carbon atoms or a group represented by the following formula (1A).)

^{(Y 1} is a single _{bond, - (CH 2) a -} (a is an integer of _{1~15), - O -, -} CH 2 O -, - COO- or OCO- .Y ² is a single bond Or — (CH ₂ ) _b — (b is an integer of 1 to 15.) Y ³ is a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 15), —O—. -CH ₂ O-, -COO- or -OCO- Y ⁴ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a heterocyclic ring (any hydrogen atom on these cyclic groups is , An alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. Or selected from the group consisting of organic groups having 12 to 25 carbon atoms having a steroid skeleton. Valent organic group .Y ⁵ is a benzene ring, any hydrogen atom on the cyclic group (which cyclic group selected from the group consisting of hexane ring and heterocyclic cycloheteroalkyl is an alkyl group having 1 to 3 carbon atoms, Y ⁶ may be substituted with an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. It is a C1-C18 fluorine-containing alkyl group, a C1-C18 alkoxyl group, or a C1-C18 fluorine-containing alkoxyl group, n is an integer of 0-4. )

(R is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (however, any hydrogen atom may be substituted with a fluorine atom), or an alkoxy group having 1 to 10 carbon atoms (provided that any of its hydrogen atoms may be substituted by a fluorine atom.) .A and B represents an independently represent any one of the ring structures shown below following formula. However, any of the ring structure The hydrogen atom may be substituted with an alkoxy group having 1 to 10 carbon atoms, T ^{1 to} T ⁴ each independently represents a single bond, an ether, an ester, an amide, or a ketone bond, and S is a single bond or Represents an alkylene group having 1 to 10 carbon atoms.)

Is 5 mol% to 50 mol% amount contained in the first diamine compound contained in the diamine component, according to claim 1, wherein the content of the second diamine compound is 20 mol% to 95 mol% Liquid crystal aligning agent. The liquid crystal aligning agent of Claim 1 or 2 whose content of the said polymer is 1-20 mass%. Furthermore, the liquid crystal aligning agent of any one of Claims 1-3 containing a crosslinking agent. The liquid crystal aligning film obtained from the liquid crystal aligning agent of any one of Claims 1-4 . The liquid crystal display element which has a liquid crystal aligning film of Claim 5 .

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