JPWO2013018904A1 - Liquid crystal aligning agent for photo-alignment treatment method, and liquid crystal alignment film using the same - Google Patents

Abstract

（Ｗ_１、Ｗ_２は、独立して、炭素数６〜３０の芳香族基を有する２価の有機基であり、Ａは、炭素数２〜２０のアルキレン基を含む２価の有機基である。）Provided are a liquid crystal alignment film capable of suppressing an afterimage caused by alternating current drive generated in a liquid crystal display element of an IPS drive method or an FFS drive method, and a liquid crystal alignment agent for the optical alignment treatment method therefor.
It contains the following (A) component, (B) component and an organic solvent, and the content of the (B) component is 0.1 to 15 parts by mass with respect to 100 parts by mass of the (A) component. Liquid crystal aligning agent.
(A) Component: By irradiating polarized radiation, reaction of photodecomposition, photodimerization or photoisomerization proceeds, and anisotropy in the same direction as the polarization direction or perpendicular to the polarization direction One or more polymers to which is given.
(B) Component: A polymer containing a structure represented by the following formula (1).
[Chemical 1]

(W ₁ and W ₂ are independently a divalent organic group having an aromatic group having 6 to 30 carbon atoms, and A is a divalent organic group containing an alkylene group having 2 to 20 carbon atoms. is there.)

Description

  The present invention relates to a liquid crystal alignment agent for producing a liquid crystal alignment film and a liquid crystal alignment film obtained from the liquid crystal alignment agent. More specifically, in place of rubbing treatment, a liquid crystal alignment agent used for forming a liquid crystal alignment film capable of imparting liquid crystal alignment ability by photo-alignment treatment, that is, irradiation with polarized ultraviolet rays, and the liquid crystal alignment agent. It relates to a liquid crystal alignment film obtained from the above.

In a liquid crystal display element used for a liquid crystal television, a liquid crystal display, and the like, a liquid crystal alignment film for controlling the alignment state of liquid crystals is usually provided in the element.
At present, according to the most widespread industrial method, the liquid crystal alignment film is made of a polyamic acid formed on an electrode substrate and / or a surface of a film made of polyimide obtained by imidizing this with cotton, nylon, It is produced by carrying out a so-called rubbing process that rubs in one direction with a cloth such as polyester.

  The method of rubbing the film surface in the alignment process of the liquid crystal alignment film is an industrially useful method that is simple and excellent in productivity. However, the demand for higher performance, higher definition, and larger size of liquid crystal display elements is increasing, and the surface of the alignment film caused by rubbing treatment, dust generation, the influence of mechanical force and static electricity, Various problems such as non-uniformity in the orientation processing surface have been revealed.

As a method for replacing the rubbing treatment, a photo-alignment method for imparting liquid crystal alignment ability by irradiating polarized radiation is known. As liquid crystal alignment treatment by the photo-alignment method, those utilizing a photoisomerization reaction, those utilizing a photocrosslinking reaction, those utilizing a photodecomposition reaction, and the like have been proposed (see Non-Patent Document 1).
When polyimide is used for the liquid crystal alignment film for photo-alignment, its usefulness is expected because it has higher heat resistance than others. Patent Document 1 proposes that a polyimide film having an alicyclic structure such as a cyclobutane ring in the main chain is used for the photo-alignment method.

The photo-alignment method as described above has been attracting attention as a rubbing-less alignment treatment method, and has an advantage that it can be produced by an industrially simple manufacturing process, as well as an IPS driving method and fringe field switching (hereinafter referred to as FFS). In the liquid crystal display element of the driving method, the obtained liquid crystal alignment film can improve performance such as the contrast and viewing angle characteristics of the liquid crystal display element can be improved as compared with the liquid crystal alignment film obtained by the rubbing treatment method. It is.
On the other hand, as the liquid crystal alignment film used for the liquid crystal display element of the IPS driving method or the FFS driving method, in addition to the basic characteristics such as excellent liquid crystal alignment property and electrical characteristics, the liquid crystal display element of the IPS driving method and the FFS driving method is used. It is necessary to suppress the afterimage by the generated AC drive. However, heretofore, a liquid crystal alignment film obtained by a photo-alignment method has insufficient alignment regulating power of liquid crystal and its stability, and it has been difficult to satisfy the above characteristics.

Japanese Unexamined Patent Publication No. 9-297313

"Liquid crystal alignment film" Kidowaki, Ichimura Functional Materials November 1997, Vol. 17 No. 11 pages 13-22

  The present invention relates to a liquid crystal alignment film for a photo-alignment processing method capable of suppressing an afterimage due to alternating current driving that occurs in a liquid crystal display element of an IPS drive system or an FFS drive system, and a photo-alignment process for obtaining the liquid crystal alignment film It aims at providing the liquid crystal aligning agent for a method.

  The present inventor has conducted extensive research to achieve the above object, and as a result of irradiating polarized radiation, any one of the reactions of photolysis, photodimerization, or photoisomerization proceeds, and polarization A polymer having anisotropy in the same direction as the direction or perpendicular to the polarization direction, a polymer having both a rigid aromatic group and a flexible alkylene group, and an organic solvent. It has been found that the above object can be achieved by a liquid crystal aligning agent.

Thus, the present invention has the following gist.
1. The following (A) component, (B) component, and an organic solvent are contained, Content of (B) component is 0.1-15 mass parts with respect to 100 mass parts of (A) component, It is characterized by the above-mentioned. Liquid crystal aligning agent.
Component (A): Irradiation with polarized radiation causes a reaction of photodecomposition, photodimerization, or photoisomerization to proceed in the same direction as the polarization direction or in a direction perpendicular to the polarization direction. One type or two or more types of polymers imparted with anisotropy.
(B) Component: A polymer containing a structure represented by the following formula (1).

（式（１）において、Ｗ_１及びＷ_２はそれぞれ独立して、炭素数６〜３０の芳香族基を有する２価の有機基であり、Ａは、炭素数２〜２０のアルキレン基を有する２価の有機基である。）
２．（Ａ）成分が、偏光された放射線を照射することにより、光分解反応が進行し、偏光方向に対して垂直方向に異方性が付与される１種又は２種以上の重合体である上記１に記載の液晶配向剤。
３．（Ａ）成分が、下記式（２）で表される構造単位を含有することを特徴とするポリイミド前駆体及び該ポリイミド前駆体のイミド化重合体からなる群から選ばれる少なくとも1種の重合体である上記１又は２に記載の液晶配向剤。

(In Formula (1), W ₁ and W ₂ are each independently a divalent organic group having an aromatic group having 6 to 30 carbon atoms, and A has an alkylene group having 2 to 20 carbon atoms. It is a divalent organic group.)
2. The component (A) is a polymer of one or more types that undergoes a photolysis reaction when irradiated with polarized radiation and imparts anisotropy in a direction perpendicular to the polarization direction. The liquid crystal aligning agent of 1.
3. The component (A) contains a structural unit represented by the following formula (2), and at least one polymer selected from the group consisting of a polyimide precursor and an imidized polymer of the polyimide precursor 3. The liquid crystal aligning agent according to 1 or 2 above.

（式（２）において、Ｘ_１は下記式（Ｘ１−１）〜（Ｘ１−９）で表される構造からなる群から選ばれる少なくとも１種であり、Ｙ_１は２価の有機基であり、Ｒ_１は、水素原子、又は炭素数１〜４のアルキル基である。）

(In the formula (2), X ₁ is at least one selected from the group consisting of structures represented by the following formulas (X1-1) to (X1-9), and Y ₁ is a divalent organic group. , R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

式（Ｘ１−１）において、Ｒ_３、Ｒ_４、Ｒ_５、及びＲ_６はそれぞれ独立して、水素原子、ハロゲン原子、炭素数１〜６のアルキル基、炭素数２〜６のアルケニル基、アルケニル基、又はフェニル基であり、同一でも異なってもよい。
４．（Ａ）成分が、上記式（２）で表される構造単位を全構造単位１モルに対して、６０モル％以上含有するポリイミド前駆体及び該ポリイミド前駆体のイミド化重合体からなる群から選ばれる少なくとも１種である上記３に記載の液晶配向剤。
５．上記式（２）において、Ｘ_１が上記式（Ｘ１−１）で表される構造からなる群から選ばれる少なくとも１種である上記３又は４に記載の液晶配向剤。
６．上記式（２）において、Ｘ_１が下記式（Ｘ１−１０）〜（Ｘ１−１１）で表される構造からなる群から選ばれる少なくとも１種である上記３〜５のいずれかに記載の液晶配向剤。

In Formula (X1-1), R ₃ , R ₄ , R ₅ , and R ₆ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, An alkenyl group or a phenyl group, which may be the same or different.
4). (A) From the group which a component consists of a polyimide precursor which contains 60 mol% or more of structural units represented by said Formula (2) with respect to 1 mol of all the structural units, and the imidation polymer of this polyimide precursor. 4. The liquid crystal aligning agent according to 3 above, which is at least one selected.
5. 5. The liquid crystal aligning agent according to 3 or 4 above, wherein in the formula (2), X ₁ is at least one selected from the group consisting of the structure represented by the formula (X1-1).
6). In the above formula (2), X ₁ is at least one selected from the group consisting of structures represented by the following formulas (X1-10) to (X1-11). Alignment agent.

７．上記式（２）において、Ｙ_１が下記式（４）及び（５）で表される構造からなる群から選ばれる少なくとも１種である上記３〜６のいずれかに記載の液晶配向剤。

7). 7. The liquid crystal aligning agent according to any one of the above 3 to 6, wherein in the formula (2), Y ₁ is at least one selected from the group consisting of structures represented by the following formulas (4) and (5).

（式（５）において、Ｚ_１は単結合、エステル結合、アミド結合、チオエステル結合、又は炭素数２〜１０の２価の有機基である。）
８．上記式（２）において、Ｙ_１が上記式（４）で表される構造である上記７に記載の液晶配向剤。
９．（Ｂ）成分が、下記式（３）で表される構造単位を有するポリイミド前駆体及び該ポリイミド前駆体のイミド化重合体からなる群から選ばれる少なくとも１種の重合体である上記１〜８のいずれかに記載の液晶配向剤。

(In Formula (5), Z ₁ is a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 10 carbon atoms.)
8). 8. The liquid crystal aligning agent according to the above 7, wherein Y ₁ is a structure represented by the above formula (4) in the above formula (2).
9. The component (B) is at least one polymer selected from the group consisting of a polyimide precursor having a structural unit represented by the following formula (3) and an imidized polymer of the polyimide precursor. The liquid crystal aligning agent in any one of.

（式（３）において、Ｘ_２は炭素数６〜２０の芳香族基を有し、且つ結合手を芳香族基に有する４価の有機基ある。Ｙ_２は下記式（Ｙ２−１）及び（Ｙ２−２）からなる群から選ばれる少なくとも１種の２価の有機基であり、Ａ_１及びＡ_２はそれぞれ独立して、水素原子、又は置換基を有してもよい炭素数１〜１０のアルキル基、アルケニル基、アルキニル基であり、Ｒ_２は水素原子、又は炭素数１〜４のアルキル基である。）

(In the formula (3), X ₂ is a tetravalent organic group having an aromatic group having 6 to 20 carbon atoms and having a bond in the aromatic group. Y ₂ represents the following formula (Y2-1) and (Y2-2) is at least one divalent organic group selected from the group consisting of, and A ₁ and A ₂ are each independently a hydrogen atom or a C ₁ -C 1 that may have a substituent. 10 is an alkyl group, an alkenyl group, or an alkynyl group, and R ₂ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

（式（Ｙ２−１）において、Ａ_３は炭素数２〜２０のアルキレン基を有する２価の有機基である。式（Ｙ２−２）において、Ａ_４は、−Ｏ−、−Ｓ−、−ＮＲ_１２−、エステル結合、アミド結合、チオエステル結合、ウレア結合、カーボネート結合、カルバメート結合であり、Ｒ_１２は、水素原子、メチル基、又はｔ−ブトキシカルボニル基であり、Ａ_５は炭素数２〜２０のアルキレン基である。）
１０．（Ｂ）成分が、上記式（３）で表される構造単位を全構造単位１モルに対して６０モル％以上含有するポリイミド前駆体及び該ポリイミド前駆体のイミド化重合体からなる群から選ばれる少なくとも１種の重合体である上記９に記載の液晶配向剤。
１１．上記式（３）のＸ_２が下記式（Ｘ２−１）〜（Ｘ２−３）で表される構造からなる群から選ばれる少なくとも１種である上記９又は１０に記載の液晶配向剤。

(In the formula (Y2-1), _{A 3} is a divalent organic group having an alkylene group having 2 to 20 carbon atoms In formula _{(Y2-2), A} 4 is, -O -., - S-, —NR ₁₂ —, ester bond, amide bond, thioester bond, urea bond, carbonate bond, carbamate bond, R ₁₂ is a hydrogen atom, methyl group, or t-butoxycarbonyl group, and A ₅ has 2 carbon atoms. ˜20 alkylene groups.)
10. The component (B) is selected from the group consisting of a polyimide precursor containing 60 mol% or more of the structural unit represented by the above formula (3) with respect to 1 mol of all structural units and an imidized polymer of the polyimide precursor. 10. The liquid crystal aligning agent according to 9 above, which is at least one polymer.
11. 11. The liquid crystal aligning agent according to 9 or 10 above, wherein X _{2 in the} formula (3) is at least one selected from the group consisting of structures represented by the following formulas (X2-1) to (X2-3).

１２．上記式（３）のＸ_２が上記式（Ｘ２−１）である上記１１に記載の液晶配向剤。
１３．上記式（３）のＹ_２が下記式（Ｙ２−３）〜（Ｙ２−１２）で表される構造からなる群から選ばれる少なくとも１種である上記９〜１２のいずれに記載の液晶配向剤。

12 12. The liquid crystal aligning agent according to 11 above, wherein X _{2 in the} formula (3) is the formula (X2-1).
13. The liquid crystal aligning agent according to any one of 9 to 12, wherein Y _{2 in the} formula (3) is at least one selected from the group consisting of structures represented by the following formulas (Y2-3) to (Y2-12). .

（式（Ｙ２−１０）及び（Ｙ２−１１）において、Ｒ_１３はそれぞれ独立して、水素原子、又は炭素数１〜１０のアルキル基であり、同一でも異なってもよい。）
１４．上記１〜１３のいずれかに記載の液晶配向剤を塗布、焼成して得られる液晶配向膜。
１５．上記１〜１３のいずれかに記載の液晶配向剤を塗布、焼成し、さらに偏光された放射線を照射して得られる液晶配向膜。
１６．上記１〜１３のいずれかに記載の液晶配向剤を塗布、焼成し、偏光された放射線を照射した後、１５０℃〜２５０℃で加熱して得られる液晶配向膜。
１７．上記１４〜１６のいずれかに記載の液晶配向膜を具備する液晶表示素子。

(In formulas (Y2-10) and (Y2-11), R ₁₃ each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, which may be the same or different.)
14 The liquid crystal aligning film obtained by apply | coating and baking the liquid crystal aligning agent in any one of said 1-13.
15. The liquid crystal aligning film obtained by apply | coating and baking the liquid crystal aligning agent in any one of said 1-13, and also irradiating the polarized radiation.
16. The liquid crystal aligning film obtained by apply | coating and baking the liquid crystal aligning agent in any one of said 1-13, irradiating with the polarized radiation, and heating at 150 to 250 degreeC.
17. 17. A liquid crystal display device comprising the liquid crystal alignment film according to any one of 14 to 16 above.

The liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention can suppress afterimages caused by alternating current drive generated in an IPS drive type or FFS drive type liquid crystal display element.
The reason why the problem of the present invention is solved in the liquid crystal alignment film of the present invention is not necessarily clear, but is considered as follows.
In general, afterimages due to alternating current drive generated in liquid crystal display elements of IPS drive system and FFS drive system are suppressed by increasing the anisotropy of the liquid crystal alignment film and / or increasing the interaction between the liquid crystal alignment film and the liquid crystal. It is known that it can be done. On the other hand, even if the liquid crystal alignment film obtained by the photo-alignment method can give sufficient anisotropy, a specific part that reacts by irradiation with radiation needs to be more than a certain ratio, and the interaction with the liquid crystal is enhanced. It was difficult. Specifically, when a structure capable of enhancing the interaction with the liquid crystal is introduced into the polymer, sufficient anisotropy is caused by a decrease in the reactivity of the photoreactive site and a decrease in the density of the photoreactive site. In some cases, it could not be obtained.

The inventors of the present application provide a liquid crystal having both a rigid skeleton containing an aromatic group and a flexible skeleton containing an alkylene group in the component (A) to which anisotropy is imparted by irradiating polarized radiation; While maintaining the anisotropy when irradiated with polarized radiation, the polymer (component (B)) containing a similar structure is preferably mixed with the component (A) in a specific amount. The present inventors have found that the interaction between the liquid crystal alignment film obtained by the photo-alignment method and the liquid crystal can be enhanced.
Since the component (B) having a skeleton similar to liquid crystal has a flexible skeleton, it is expected to have high mobility when heated. There are some heating processes during the photo-alignment treatment and the liquid crystal display element manufacturing. The inventors of the present application considered that the mobility of the component (B) is improved during this heating step, and reorientation is performed along the anisotropy imparted by irradiation with polarized radiation. By reorienting the component (B), it is considered that a liquid crystal alignment film having high anisotropy and high interaction with the liquid crystal can be obtained even in a liquid crystal alignment film obtained by a photo-alignment method.

  From the above, the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention has high liquid crystal alignment properties and can suppress an afterimage caused by alternating current drive generated in an IPS drive type or FFS drive type liquid crystal display element. It is considered possible.

<(A) component>
The component (A) contained in the liquid crystal aligning agent of the present invention undergoes a reaction of photodecomposition, photodimerization, or photoisomerization when irradiated with polarized radiation, and is in the same direction as the polarization direction. Or one or two or more polymers imparted with anisotropy in the direction perpendicular to the polarization direction.

The component (A) of the present invention is not particularly limited as long as it is a polymer having a site where any of the reactions of photodecomposition, photodimerization, or photoisomerization proceeds upon irradiation with radiation. If a specific example is given, the structure in which the photodimerization reaction proceeds includes a polymer containing a structure having a cinnamoyl group represented by the following formula (A-1). Examples of the structure in which the photoisomerization reaction proceeds include a polymer containing an azobenzene skeleton represented by the following formula (A-2). The structure in which the photolysis reaction proceeds is at least one selected from the group consisting of a polymer containing an imide skeleton having an alicyclic group represented by the following formula (A-3) and a precursor of the polymer. These polymers are mentioned.
In the formula (A-1), Q is a divalent aromatic group. In the formula (A-3), X is a tetravalent alicyclic group, and Y is a divalent organic group.
When the obtained liquid crystal alignment film has high heat resistance and a liquid crystal display element, a highly reliable liquid crystal display element with a high voltage holding ratio is obtained, and the obtained liquid crystal alignment film has high anisotropy. An imide skeleton having an alicyclic group represented by the formula (A-3) and an imidized polymer having an imide skeleton are more preferable.

式（Ａ−１）において、Ｑは２価の芳香族基である。式（Ａ−３）において、Ｘは、４価の脂環式基であり、Ｙは２価の有機基である。
脂環式骨格を有するイミド構造を含有する重合体及び該重合体の前駆体としては、光反応の感度が高く、得られる液晶配向膜の異方性が高いため、本発明に記載の（Ａ）成分としては、下記式（２）で表される構造単位を有するポリイミド前駆体及び該ポリイミド前駆体のイミド化重合体が好ましい。有機溶媒への溶解性の観点から、下記式（２）で表される構造単位を含有するポリイミド前駆体が特に好ましい。

In the formula (A-1), Q is a divalent aromatic group. In the formula (A-3), X is a tetravalent alicyclic group, and Y is a divalent organic group.
A polymer containing an imide structure having an alicyclic skeleton and a precursor of the polymer have high photoreaction sensitivity and high anisotropy of the obtained liquid crystal alignment film. The component is preferably a polyimide precursor having a structural unit represented by the following formula (2) and an imidized polymer of the polyimide precursor. From the viewpoint of solubility in an organic solvent, a polyimide precursor containing a structural unit represented by the following formula (2) is particularly preferable.

式（２）において、Ｒ_１は、水素原子、又は炭素数１〜４のアルキル基である。加熱によるイミド化のしやすさの観点から、水素原子、又はメチル基が特に好ましい。Ｘ_１は下記式（Ｘ１−１）〜（Ｘ１−９）で表される構造からなる群から選ばれる少なくとも１種である。

In Formula (2), R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. From the viewpoint of ease of imidization by heating, a hydrogen atom or a methyl group is particularly preferable. X ₁ is at least one selected from the group consisting of structures represented by the following formulas (X1-1) to (X1-9).

式（Ｘ１−１）において、Ｒ_３、Ｒ_４、Ｒ_５、及びＲ_６はそれぞれ独立して、水素原子、ハロゲン原子、炭素数１〜６のアルキル基、炭素数２〜６のアルケニル基、アルケニル基、又はフェニル基であり、同一でも異なってもよい。液晶配向性の観点から、Ｒ_１、Ｒ_２、Ｒ_３，及びＲ_４は、水素原子、ハロゲン原子、メチル基、又はエチル基が好ましく、水素原子、又はメチル基がより好ましく、さらに好ましくは、下記式（Ｘ１−１０）〜（Ｘ１−１１）で表される構造からなる群から選ばれる少なくとも１種である。

In Formula (X1-1), R ₃ , R ₄ , R ₅ , and R ₆ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, An alkenyl group or a phenyl group, which may be the same or different. From the viewpoint of liquid crystal orientation, R ₁ , R ₂ , R ₃ , and R ₄ are preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, more preferably a hydrogen atom or a methyl group, and still more preferably, It is at least one selected from the group consisting of structures represented by the following formulas (X1-10) to (X1-11).

Ｙ_１は、２価の有機基であり、その構造は特に限定されるものではない。得られる液晶配向膜の異方性が高いため、下記式（４）及び（５）で表される構造からなる群から選ばれる少なくとも１種であることが好ましい。

Y ₁ is a divalent organic group, and its structure is not particularly limited. Since the obtained liquid crystal alignment film has high anisotropy, it is preferably at least one selected from the group consisting of structures represented by the following formulas (4) and (5).

式（５）において、Ｚ_１は単結合、エステル結合、アミド結合、チオエステル結合、又は炭素数２〜１０の２価の有機基である。
Ｚ_１において、エステル結合としては、−Ｃ（Ｏ）Ｏ−、又は−ＯＣ（Ｏ）−で表される。アミド結合としては、−Ｃ（Ｏ）ＮＨ−、又は、−Ｃ（Ｏ）ＮＲ−、−ＮＨＣ（Ｏ）−、−ＮＲＣ（Ｏ）−で表される構造を示すことができる。Ｒは、炭素数１〜１０を有する、アルキル基、アルケニル基、アルキニル基、アリール基、若しくはこれらの組み合わせである。

In Formula (5), Z ₁ is a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 10 carbon atoms.
In Z _1, the ester bond, -C (O) O-, or -OC (O) - represented by. As an amide bond, the structure represented by -C (O) NH- or -C (O) NR-, -NHC (O)-, -NRC (O)-can be shown. R is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a combination thereof having 1 to 10 carbon atoms.

Specific examples of the alkyl group include a methyl group, ethyl group, propyl group, butyl group, t-butyl group, hexyl group, octyl group, cyclopentyl group, cyclohexyl group, and bicyclohexyl group. Examples of the alkenyl group include those obtained by replacing one or more CH—CH structures present in the above alkyl group with C═C structures, and more specifically, vinyl groups, allyl groups, 1-propenyl groups. , Isopropenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group, 2-hexenyl group, cyclopropenyl group, cyclopentenyl group, cyclohexenyl group and the like. Alkynyl groups include those in which one or more CH ₂ —CH ₂ structures present in the alkyl group are replaced with C≡C structures, and more specifically, ethynyl groups, 1-propynyl groups, 2 -A propynyl group etc. are mentioned. Examples of the aryl group include a phenyl group.
As the thioester bond, a structure represented by -C (O) S- or -SC (O)-can be shown.
When Z ₁ is an organic group having 2 to 10 carbon atoms, it can be represented by the structure of the following formula (6).

式（６）における、Ｚ₄、Ｚ_５、Ｚ_６はそれぞれ独立して、単結合、−Ｏ−、−Ｓ−、−ＮＲ_１１−、エステル結合、アミド結合、チオエステル結合、ウレア結合、カーボネート結合、又はカルバメート結合である。Ｒ_１１は、水素原子、メチル基、又はｔ−ブトキシカルボニル基である。

In formula (6), Z ₄ , Z ₅ and Z ₆ are each independently a single bond, —O—, —S—, —NR ₁₁ —, an ester bond, an amide bond, a thioester bond, a urea bond, or a carbonate bond. Or a carbamate bond. R ₁₁ is a hydrogen atom, a methyl group, or a t-butoxycarbonyl group.

In Z ₄ , Z ₅ , and Z ₆ , the ester bond, amide bond, and thioester bond can have the same structures as the ester bond, amide bond, and thioester bond described above.

As a urea bond, the structure represented by -NH-C (O) NH- or -NR-C (O) NR- can be shown. R is an alkyl group having 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, an aryl group, or a combination thereof, and examples thereof are the same as the above-described alkyl group, alkenyl group, alkynyl group, and aryl group.
As a carbonate bond, the structure represented by -O-C (O) -O- can be shown.
The carbamate bond is -NH-C (O) -O-, -O-C (O) -NH-, -NR-C (O) -O-, or -O-C (O) -NR-. The structure represented can be shown. R is an alkyl group having 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, an aryl group, or a combination thereof, and examples thereof are the same as the above-described alkyl group, alkenyl group, alkynyl group, and aryl group.

R ₉ and R _{10 in} Formula (6) are each independently a single bond or a structure selected from an alkylene group having 1 to 10 carbon atoms, an alkenylene group, an alkynylene group, an arylene group, and a group obtained by combining these. is there. If one of R ₉ and R ₁₀ is a single bond, R ₉ or R ₁₀ is a structure selected from an alkylene group, an alkenylene group, an alkynylene group, an arylene group, and a group composed of a combination of these having 2 to 10 carbon atoms .

  As said alkylene group, the structure remove | excluding one hydrogen atom from the said alkyl group is mentioned. More specifically, a methylene group, 1,1-ethylene group, 1,2-ethylene group, 1,2-propylene group, 1,3-propylene group, 1,4-butylene group, 1,2-butylene group 1,2-pentylene group, 1,2-hexylene group, 2,3-butylene group, 2,4-pentylene group, 1,2-cyclopropylene group, 1,2-cyclobutylene group, 1,3- Examples include a cyclobutylene group, a 1,2-cyclopentylene group, and a 1,2-cyclohexylene group.

  The alkenylene group includes a structure in which one hydrogen atom is removed from the alkenyl group. More specifically, 1,1-ethenylene group, 1,2-ethenylene group, 1,2-ethenylenemethylene group, 1-methyl-1,2-ethenylene group, 1,2-ethenylene-1,1- Ethylene group, 1,2-ethenylene-1,2-ethylene group, 1,2-ethenylene-1,2-propylene group, 1,2-ethenylene-1,3-propylene group, 1,2-ethenylene-1, Examples include 4-butylene group and 1,2-ethenylene-1,2-butylene group.

Examples of the alkynylene group include a structure in which one hydrogen atom is removed from the alkynyl group. More specifically, an ethynylene group, an ethynylene methylene group, an ethynylene-1,1-ethylene group, an ethynylene-1,2-ethylene group, an ethynylene-1,2-propylene group, an ethynylene-1,3-propylene group, Examples include ethynylene-1,4-butylene group, ethynylene-1,2-butylene group and the like.
The arylene group includes a structure in which one hydrogen atom is removed from the aryl group. More specifically, a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, and the like can be given.

When Y ₁ has a structure with high linearity or a rigid structure, a liquid crystal alignment film having good liquid crystal alignment can be obtained. Therefore, Z ₁ is a single bond or the following formulas (A1-1) to (A1- The structure of 25) is more preferable.

Ｙ_１が剛直な構造であるほど、液晶配向性に優れた液晶配向膜が得られるため、Ｙ_１は、上記式（４）で表される構造が特に好ましい。
上記式（２）で表される構造単位を含有するポリイミド前駆体及び該ポリイミド前駆体のイミド化重合体において、上記式（２）で表される構造単位の比率は、重合体中の全構造単位１モルに対して、６０モル％〜１００モル％が好ましい。上記式（２）で表される構造単位の比率が高いほど、良好な液晶配向性を有する液晶配向膜が得られるため、８０モル％〜１００モル％がより好ましく、９０モル％〜１００モル％がさらに好ましい。
本発明の（Ａ）成分は、上記式（２）で表される構造単位以外に、下記式（７）で表される構造単位を有するポリイミド前駆体及び該ポリイミド前駆体であってもよい。

Since Y ₁ has a more rigid structure, a liquid crystal alignment film having excellent liquid crystal alignment can be obtained. Therefore, Y ₁ is particularly preferably a structure represented by the above formula (4).
In the polyimide precursor containing the structural unit represented by the above formula (2) and the imidized polymer of the polyimide precursor, the ratio of the structural unit represented by the above formula (2) is the total structure in the polymer. 60 mol%-100 mol% are preferable with respect to 1 mol of units. As the ratio of the structural unit represented by the above formula (2) is higher, a liquid crystal alignment film having better liquid crystal alignment is obtained, so that 80 mol% to 100 mol% is more preferable, and 90 mol% to 100 mol%. Is more preferable.
The component (A) of the present invention may be a polyimide precursor having a structural unit represented by the following formula (7) in addition to the structural unit represented by the above formula (2) and the polyimide precursor.

式（７）において、Ｒ_１は上記式（２）のＲ_１と同様の定義である。Ｘ_３は４価の有機基であり、その構造は特に限定されない。具体的例を挙げるならば、下記式（Ｘ−９）〜（Ｘ−４２）の構造が挙げられる。化合物の入手性の観点から、Ｘは、Ｘ−１７、Ｘ−２５、Ｘ−２６，Ｘ−２７、Ｘ−２８、Ｘ−３２、又はＸ−３９が挙げられる。また、直流電圧により蓄積した残留電荷の緩和が早い液晶配向膜を得られるという観点から、芳香族環構造を有するテトラカルボン酸二無水物を用いることが好ましく、Ｘは、Ｘ−２６，Ｘ−２７、Ｘ−２８、Ｘ−３２、Ｘ−３５、又はＸ−３７がより好ましい。

In the formula (7), _{R 1} is the same as defined for _{R 1} in the formula (2). X ₃ is a tetravalent organic group, and its structure is not particularly limited. If a specific example is given, the structure of following formula (X-9)-(X-42) will be mentioned. From the viewpoint of availability of the compound, X includes X-17, X-25, X-26, X-27, X-28, X-32, or X-39. Further, from the viewpoint of obtaining a liquid crystal alignment film in which the residual charge accumulated by direct current voltage can be quickly relaxed, it is preferable to use a tetracarboxylic dianhydride having an aromatic ring structure, and X is X-26, X-- 27, X-28, X-32, X-35, or X-37 is more preferable.

上記式（７）において、Ｙ_３は２価の有機基であり、その構造は特に限定されない。Ｙ_３の具体例を挙げるならば、下記記式（Ｙ−１）〜（Ｙ−７４）が挙げられる。

In the above formula (7), Y ₃ is a divalent organic group, and its structure is not particularly limited. If Y ₃ Specific examples include the following above formula (Y-1) ~ (Y -74).

（Ａ）成分の有機溶剤に対する溶解性の向上が期待できるため、式（４）及び式（５）以外の構造としては、Ｙ−８、Ｙ−２０、Ｙ−２１、Ｙ−２２、Ｙ−２８、Ｙ−２９、Ｙ−３０、Ｙ−７２、Ｙ−７３、又はＹ−７４を有する構造単位を含有することが好ましい。
（Ａ）成分における上記式（７）で表される構造単位の比率が高い場合、液晶配向膜の液晶配向性を低下させるため、上記式（７）で表される構造単位の比率は、全構造単位１モルに対して０〜４０モル％が好ましく、０〜２０モル％がさらに好ましい。

Since the improvement of the solubility with respect to the organic solvent of (A) component can be anticipated, as structures other than Formula (4) and Formula (5), Y-8, Y-20, Y-21, Y-22, Y- 28, Y-29, Y-30, Y-72, Y-73, or a structural unit having Y-74 is preferably contained.
When the ratio of the structural unit represented by the above formula (7) in the component (A) is high, the ratio of the structural unit represented by the above formula (7) is 0-40 mol% is preferable with respect to 1 mol of structural units, and 0-20 mol% is more preferable.

式（１）において、Ｗ_１及びＷ_２はそれぞれ独立して、炭素数６〜３０の芳香族基を有する２価の有機基であり、同一でも異なってもよい。Ｗ_１及びＷ_２に含まれる芳香族基としては、ベンゼン、ナフタレン、アントラセン、ビフェニル、又はターフェニルが挙げられる。Ａは、炭素数２〜２０のアルキレン基を有する２価の有機基である。炭素数２〜２０のアルキレン基としては、１，１−エチレン基、１，２−エチレン基、１，２−プロピレン基、１，３−プロピレン基、１，４−ブチレン基、１，５−ペンチレン基、１，６−へキシレン基、２，３−ブチレン基、２，４−ペンチレン基などが挙げられる。
高い液晶配向性を有する液晶配向膜が得られるため、（Ｂ）成分は、上記式（１）で表される構造を含有するポリイミド前駆体及び該ポリイミド前駆体のイミド化重合体からなる群から選ばれる少なくとも１種の重合体であることが好ましい。
具体的には、下記式（３）で表される構造単位を有するポリイミド前駆体及び該ポリイミド前駆体のイミド化重合体からなる群から選ばれる少なくとも１種であることがより好ましい。<(B) component>
The component (B) of the present invention is a polymer containing a structure represented by the following formula (1).

In Formula (1), W ₁ and W ₂ are each independently a divalent organic group having an aromatic group having 6 to 30 carbon atoms, and may be the same or different. Examples of the aromatic group contained in W ₁ and W ₂ include benzene, naphthalene, anthracene, biphenyl, and terphenyl. A is a divalent organic group having an alkylene group having 2 to 20 carbon atoms. Examples of the alkylene group having 2 to 20 carbon atoms include 1,1-ethylene group, 1,2-ethylene group, 1,2-propylene group, 1,3-propylene group, 1,4-butylene group, 1,5- A pentylene group, a 1,6-hexylene group, a 2,3-butylene group, a 2,4-pentylene group, and the like can be given.
Since a liquid crystal alignment film having high liquid crystal alignment properties is obtained, the component (B) is selected from the group consisting of a polyimide precursor containing a structure represented by the above formula (1) and an imidized polymer of the polyimide precursor. It is preferable that it is at least one polymer selected.
Specifically, at least one selected from the group consisting of a polyimide precursor having a structural unit represented by the following formula (3) and an imidized polymer of the polyimide precursor is more preferable.

式（３）において、Ｒ_２は好ましい例も含めて上記式（２）のＲ_１と同様の定義である。Ａ_１及びＡ_２は、それぞれ独立して水素原子、又は置換基を有してもよい炭素数１〜１０のアルキル基、アルケニル基、又はアルキニル基であり、前記のアルキル基、アルケニル基、アルキニル基と同様の構造を挙げることができる。

In Formula (3), R ₂ is the same definition as R _{1 in} Formula (2), including preferred examples. A ₁ and A ₂ are each independently a hydrogen atom or an optionally substituted alkyl group, alkenyl group, or alkynyl group having 1 to 10 carbon atoms, and the aforementioned alkyl group, alkenyl group, alkynyl group The same structure as a group can be mentioned.

The above alkyl group, alkenyl group, and alkynyl group may have a substituent as long as it has 1 to 10 carbon atoms as a whole, and may further form a ring structure with the substituent. Note that forming a ring structure with a substituent means that the substituents or a substituent and a part of the mother skeleton are bonded to form a ring structure.
Examples of such substituents are halogen groups, hydroxyl groups, thiol groups, nitro groups, aryl groups, organooxy groups, organothio groups, organosilyl groups, acyl groups, ester groups, thioester groups, phosphate ester groups, amide groups, alkyls. A group, an alkenyl group and an alkynyl group.
Examples of the halogen group as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
A phenyl group is mentioned as an aryl group which is a substituent. This aryl group may be further substituted with the other substituent described above.
The organooxy group which is a substituent can have a structure represented by OR. The R may be the same or different, and examples thereof include the alkyl group, alkenyl group, alkynyl group, and aryl group described above. These Rs may be further substituted with the substituent described above. Specific examples of the alkyloxy group include methoxy group, ethoxy group, propyloxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group and the like.

As the organothio group which is a substituent, the structure represented by -S-R can be shown. Examples of R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These Rs may be further substituted with the substituent described above. Specific examples of the alkylthio group include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, and an octylthio group.
As the organosilyl group which is a substituent, a structure represented by -Si- (R) ₃ can be shown. The R may be the same or different, and examples thereof include the alkyl group, alkenyl group, alkynyl group, and aryl group described above. These Rs may be further substituted with the substituent described above. Specific examples of the alkylsilyl group include a trimethylsilyl group, a triethylsilyl group, a tripropylsilyl group, a tributylsilyl group, a tripentylsilyl group, a trihexylsilyl group, a pentyldimethylsilyl group, and a hexyldimethylsilyl group.
As an acyl group which is a substituent, the structure represented by -C (O) -R can be shown. Examples of R include the above-described alkyl group, alkenyl group, and aryl group. These Rs may be further substituted with the substituent described above. Specific examples of the acyl group include formyl group, acetyl group, propionyl group, butyryl group, isobutyryl group, valeryl group, isovaleryl group, benzoyl group and the like.
As an ester group which is a substituent, the structure represented by -C (O) O-R or -OC (O) -R can be shown. Examples of R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These Rs may be further substituted with the substituent described above.

As a thioester group which is a substituent, the structure represented by -C (S) O-R or -OC (S) -R can be shown. Examples of R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These Rs may be further substituted with the substituent described above.
As a phosphate group which is a substituent, the structure represented by -OP (O)-(OR) ₂ can be shown. The R may be the same or different, and examples thereof include the alkyl group, alkenyl group, alkynyl group, and aryl group described above. These Rs may be further substituted with the substituent described above.
Examples of the amide group is a _{substituent, -C (O) NH 2,} -C (O) NHR, -NHC (O) R, -C (O) N (R) 2, or, -NRC (O) R The structure represented by can be shown. The R may be the same or different, and examples thereof include the alkyl group, alkenyl group, alkynyl group, and aryl group described above. These Rs may be further substituted with the substituent described above.
Examples of the aryl group as a substituent include the same aryl groups as described above. This aryl group may be further substituted with the other substituent described above.
Examples of the alkyl group as a substituent include the same alkyl groups as described above. This alkyl group may be further substituted with the other substituent described above.
Examples of the alkenyl group as a substituent include the same alkenyl groups as described above. This alkenyl group may be further substituted with the other substituent described above.
Examples of the alkynyl group that is a substituent include the same alkynyl groups as described above. This alkynyl group may be further substituted with the other substituent described above.

In general, when a bulky structure is introduced, there is a possibility that the reactivity of the amino group and the liquid crystal orientation may be lowered. Therefore, as A ₁ and A ₂ , a hydrogen atom or a carbon atom that may have a substituent is 1 The alkyl group of ˜5 is more preferable, and a hydrogen atom, a methyl group or an ethyl group is particularly preferable.
X ₂ is a tetravalent organic group having an aromatic group having 6 to 20 carbon atoms and having a bond in the aromatic group. Examples of the aromatic group having 6 to 20 carbon atoms include benzene, naphthalene, anthracene, biphenyl, and terphenyl. X ₂ is preferably a tetravalent organic group consisting only of an aromatic group, more preferably the following formulas (X2-1) to (X), since the interaction with the liquid crystal is enhanced and the effect of suppressing the afterimage is enhanced. And a structure represented by X2-3). Among these, a structure represented by the formula (X2-1) is particularly preferable.

Ｙ_２は、下記式（Ｙ２−１）〜（Ｙ２−２）からなる群から選ばれる少なくとも１種の２価の有機基である。

Y ₂ is at least one divalent organic group selected from the group consisting of the following formulas (Y2-1) to (Y2-2).

式（Ｙ２−１）において、Ａ_３は、炭素数２〜２０のアルキレン基を有する２価の有機基であり、アルキレン基を複数有しても構わない。炭素数２〜２０のアルキレン基としては、１，１−エチレン基、１，２−エチレン基、１，２−プロピレン基、１，３−プロピレン基、１，４−ブチレン基、１，５−ペンチレン基、１，６−へキシレン基、２，３−ブチレン基、２，４−ペンチレン基などが挙げられる。液晶配向性の観点から、Ａ_３は炭素数２〜１０のアルキレン基を有する２価の有機基であることが好ましい。
式（Ｙ２−２）において、Ａ_４は、単結合、−Ｏ−、−Ｓ−、−ＮＲ_１２−、エステル結合、アミド結合、チオエステル結合、ウレア結合、カーボネート結合、又はカルバメート結合であり、Ｒ_１２は、水素原子、メチル基、又はｔ−ブトキシカルボニル基であり、これらは前記のものと同様の構造を示すことができる。液晶配向性の観点から、Ａ_５は炭素数２〜２０のアルキレン基であり、前記のアルキレン基と同様の構造を示すことができる。液晶配向性の観点から、Ａ_４は単結合が好ましく、Ａ_５は炭素数２〜６のアルキレン基が好ましい。
液晶との相互作用を高め、液晶配向性を向上できるＹ_２の具体例としては、下記式（Ｙ２−３）〜（Ｙ２−１２）で表される構造が挙げられる。中でも、下記式（Ｙ２−３）で表される構造が特に好ましい。

In the formula (Y2-1), _{A 3} is a divalent organic group having an alkylene group having 2 to 20 carbon atoms, may be a plurality of alkylene groups. Examples of the alkylene group having 2 to 20 carbon atoms include 1,1-ethylene group, 1,2-ethylene group, 1,2-propylene group, 1,3-propylene group, 1,4-butylene group, 1,5- A pentylene group, a 1,6-hexylene group, a 2,3-butylene group, a 2,4-pentylene group, and the like can be given. From the viewpoint of liquid crystal orientation, A ₃ is preferably a divalent organic group having an alkylene group having 2 to 10 carbon atoms.
In the formula (Y2-2), A ₄ is a single bond, —O—, —S—, —NR ₁₂ —, an ester bond, an amide bond, a thioester bond, a urea bond, a carbonate bond, or a carbamate bond; ₁₂ is a hydrogen atom, a methyl group, or a t-butoxycarbonyl group, which can have the same structure as described above. From the viewpoint of liquid crystal alignment property, A ₅ is an alkylene group having 2 to 20 carbon atoms, it is possible to indicate the same structure as the alkylene group of the. From the viewpoint of liquid crystal orientation, A ₄ is preferably a single bond, and A ₅ is preferably an alkylene group having 2 to 6 carbon atoms.
Specific examples of Y ₂ that can enhance the interaction with the liquid crystal and improve the liquid crystal alignment include structures represented by the following formulas (Y2-3) to (Y2-12). Among these, a structure represented by the following formula (Y2-3) is particularly preferable.

上記式（３）で表される構造単位を含有するポリイミド前駆体及び該ポリイミド前駆体のイミド化重合体において、上記式（３）で表される構造単位の比率は、重合体中の全構造単位１モルに対して、６０モル％〜１００モル％が好ましい。上記式（３）で表される構造単位の比率が高いほど、良好な液晶配向性を有する液晶配向膜が得られるため、８０モル％〜１００モル％がより好ましく、９０モル％〜１００モル％がさらに好ましい。
本発明に用いられる（Ｂ）成分は上記式（３）で表される構造単位以外に下記式（８）で表される構造単位を含有するポリイミド前駆体及び該ポリイミド前駆体であってもよい。

In the polyimide precursor containing the structural unit represented by the above formula (3) and the imidized polymer of the polyimide precursor, the ratio of the structural unit represented by the above formula (3) is the total structure in the polymer. 60 mol%-100 mol% are preferable with respect to 1 mol of units. As the ratio of the structural unit represented by the above formula (3) is higher, a liquid crystal alignment film having better liquid crystal alignment is obtained, so that 80 mol% to 100 mol% is more preferable, and 90 mol% to 100 mol%. Is more preferable.
The component (B) used in the present invention may be a polyimide precursor containing a structural unit represented by the following formula (8) in addition to the structural unit represented by the above formula (3) and the polyimide precursor. .

式（８）において、Ｒ_２、Ａ_１、及びＡ_２は、式（３）におけるＲ_２、Ａ_１、及びＡ_２と好ましい例も含めて同様の定義である。Ｘ_４は、脂環式基を有する４価の有機基であり、脂環式基を有する４価の有機基であれば、その構造は特に限定されない。その具体例を挙げるとするならば、上記式（Ｘ１−１）〜（Ｘ１−９）、（Ｘ−９）〜（Ｘ−１５）、（Ｘ−２２〜２５）、（Ｘ−３９）、（Ｘ−４０）が挙げられる。Ｙ_４は２価の有機基であり、その構造は特に限定されるものではない。その具体例を挙げるとするならば、上記式（Ｙ２−３）〜（Ｙ２−１２）、上記式（４）、上記式（５）、式（Ｙ−１）〜（Ｙ−７４）が挙げられる。
（Ｂ）成分に含有される上記式（８）で表される構造単位の比率が高い場合、液晶配向膜の液晶配向性を低下させるため、上記式（８）で表される構造単位の比率は、全構造単位１モルに対して０〜４０モル％が好ましく、０〜２０モル％がさらに好ましい。

In the formula _(8), R 2, _{A 1,} and _{A 2} are the same as defined, including preferred examples and _R 2, _{A 1,} and _{A 2} in Formula (3). X ₄ is a tetravalent organic group having an alicyclic group, and the structure thereof is not particularly limited as long as it is a tetravalent organic group having an alicyclic group. Specific examples thereof include the above formulas (X1-1) to (X1-9), (X-9) to (X-15), (X-22 to 25), (X-39), (X-40). Y ₄ is a divalent organic group, and its structure is not particularly limited. Specific examples thereof include the above formulas (Y2-3) to (Y2-12), the above formula (4), the above formula (5), and the formulas (Y-1) to (Y-74). It is done.
When the ratio of the structural unit represented by the above formula (8) contained in the component (B) is high, the ratio of the structural unit represented by the above formula (8) is decreased in order to reduce the liquid crystal orientation of the liquid crystal alignment film. Is preferably from 0 to 40 mol%, more preferably from 0 to 20 mol%, based on 1 mol of all structural units.

<Method for producing polyimide precursor>
The polyamic acid ester which is a polyimide precursor used in the present invention can be synthesized by the following methods (1) to (3).
(1) When synthesizing from polyamic acid The polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from tetracarboxylic dianhydride and diamine.
Specifically, the polyamic acid and the esterifying agent are reacted in the presence of an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C., for 30 minutes to 24 hours, preferably 1 to 4 hours. Can be synthesized.
As the esterifying agent, those that can be easily removed by purification are preferred, and N, N-dimethylformamide dimethyl acetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide Dineopentyl butyl acetal, N, N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p -Tolyltriazene, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride and the like. The addition amount of the esterifying agent is preferably 2 to 6 molar equivalents per 1 mol of the polyamic acid repeating unit.
The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the solubility of the polymer, and these may be used alone or in combination of two or more. Good. The concentration at the time of synthesis is preferably 1 to 30% by mass and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is unlikely to occur and a high molecular weight body is easily obtained.

(2) When synthesized by reaction of tetracarboxylic acid diester dichloride and diamine Polyamic acid ester can be synthesized from tetracarboxylic acid diester dichloride and diamine.
Specifically, tetracarboxylic acid diester dichloride and diamine in the presence of a base and an organic solvent are −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C., 30 minutes to 24 hours, preferably 1 to 4 hours. It can be synthesized by reacting.
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 times the molar amount of the tetracarboxylic acid diester dichloride from the viewpoint of easy removal and high molecular weight.
The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in view of the solubility of the monomer and polymer, and these may be used alone or in combination. The polymer concentration at the time of synthesis is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation hardly occurs and a high molecular weight body is easily obtained. 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, and it is preferable to prevent mixing of outside air in a nitrogen atmosphere.

(3) When a polyamic acid is synthesized from a tetracarboxylic acid diester and a diamine The polyamic acid ester can be synthesized by polycondensation of a tetracarboxylic acid diester and a diamine.
Specifically, tetracarboxylic acid diester and diamine in the presence of a condensing agent, a base and an organic solvent are 0 ° C. to 150 ° C., preferably 0 ° C. to 100 ° C., 30 minutes to 24 hours, preferably 3 to 15 hours. It can be synthesized by reacting.
Examples of the condensing agent include triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N′-carbonyldiimidazole, dimethoxy-1,3,5-triazi Nylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N , N ′, N′-tetramethyluronium hexafluorophosphate, diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate, and the like. It is preferable that the addition amount of a condensing agent is 2-3 times mole with respect to tetracarboxylic-acid diester.
As the base, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the base is preferably 2 to 4 moles relative to the diamine component from the viewpoint that it can be easily removed and a high molecular weight product can be easily obtained.
In the above reaction, the reaction proceeds efficiently by adding Lewis acid as an additive. 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 to 1.0 times the mole of the diamine component.

Among the methods for synthesizing the three polyamic acid esters, since a high molecular weight polyamic acid ester is obtained, the synthesis method (1) or (2) is particularly preferable.
The polyamic acid ester solution obtained as described above can be polymerized by pouring into a poor solvent while stirring well. Precipitation is performed several times, and after washing with a poor solvent, a purified polyamic acid ester powder can be obtained at room temperature or by heating and drying. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene etc. are mentioned.

<Method for producing polyamic acid>
The polyamic acid which is a polyimide precursor used in the present invention can be synthesized by the following method.
Specifically, tetracarboxylic dianhydride and diamine are reacted in the presence of an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C. for 30 minutes to 24 hours, preferably 1 to 12 hours. Can be synthesized.
The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the solubility of the monomer and the polymer, and these may be used alone or in combination of two or more. It may be used. The concentration of the polymer is preferably 1 to 30% by mass and more preferably 5 to 20% by mass from the viewpoint that the polymer is hardly precipitated and a high molecular weight body is easily obtained.
The polyamic acid obtained as described above can be recovered by precipitating the polymer by pouring into the poor solvent while thoroughly stirring the reaction solution. Moreover, the powder of polyamic acid refine | purified by performing precipitation several times, washing | cleaning with a poor solvent, and normal temperature or heat-drying can be obtained. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene etc. are mentioned.

<Production method of polyimide>
The polyimide used in the present invention can be produced by imidizing the polyimide precursor such as the polyamic acid ester or polyamic acid. When a polyimide is produced from a polyamic acid ester, chemical imidization in which a basic catalyst is added to a polyamic acid solution obtained by dissolving the polyamic acid ester solution or the polyamic acid ester resin powder in an organic solvent is simple. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is unlikely to decrease during the imidization process.
Chemical imidation can be performed by stirring the polyamic acid ester to be imidized in an organic solvent in the presence of a basic catalyst. As an organic solvent, the solvent used at the time of the polymerization reaction mentioned above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, triethylamine is preferred because it has sufficient basicity to allow the reaction to proceed.

The temperature at which the imidization reaction is performed is -20 ° C to 140 ° C, preferably 0 ° C to 100 ° C, and the reaction time can be 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 moles, preferably 2 to 20 moles, of the amic acid ester group. The imidation ratio of the resulting polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. Since the added catalyst or the like remains in the solution after the imidation reaction, the obtained imidized polymer is recovered by the means described below, redissolved in an organic solvent, and the liquid crystal alignment according to the present invention. It is preferable to use an agent.
When manufacturing a polyimide from a polyamic acid, chemical imidation which adds a catalyst to the solution of the said polyamic acid obtained by reaction with a diamine component and tetracarboxylic dianhydride is simple. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is unlikely to decrease during the imidization process.

  Chemical imidation can be performed by stirring a polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As an organic solvent, the solvent used at the time of the polymerization reaction mentioned above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, 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 temperature at which the imidization reaction is performed is -20 ° C to 140 ° C, preferably 0 ° C to 100 ° C, and the reaction time can be 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times of the amic acid group, and the amount of the acid anhydride is 1 to 50 mol times, preferably 3 to 30 mol of the amic acid group. Is double. The imidation ratio of the resulting polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time.
In the solution after the imidation reaction of polyamic acid ester or polyamic acid, the added catalyst and the like remain, so the obtained imidized polymer is recovered by the means described below, and redissolved in an organic solvent. Thus, the liquid crystal aligning agent of the present invention is preferable.
The polyimide solution obtained as described above can be polymerized by pouring into a poor solvent while stirring well. Precipitation is performed several times, and after washing with a poor solvent, a purified polyamic acid ester powder can be obtained at room temperature or by heating and drying.
The poor solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of this invention has the form of the solution in which (A) component and (B) component were melt | dissolved in the organic solvent. As for the molecular weight of the polymer of the component (A) and the component (B), the weight average molecular weight is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, still more preferably, 10,000 to 100,000. The number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and still more preferably 5,000 to 50,000.
The concentration of the polymer containing the component (A) and the component (B) contained in the liquid crystal aligning agent of the present invention can be appropriately changed depending on the setting of the thickness of the coating film to be formed. It is preferably 1% by mass or more from the viewpoint of forming a coating film having no coating, and is preferably 10% by weight or less from the viewpoint of storage stability of the solution. 2-8 mass% is especially preferable.
The component (A) in the liquid crystal aligning agent of the present invention is organic in order to exhibit high anisotropy when irradiated with polarized radiation and to exhibit good liquid crystal alignment when used as a liquid crystal alignment film. The content is usually 1 to 10% by mass, preferably 2 to 8% by mass, based on the solvent. Moreover, when there is too much content of (B) component contained in a liquid crystal aligning agent, even if it irradiates with the polarized radiation, anisotropy will not be obtained, but when liquid crystal orientation becomes inadequate and it is too small. The effects of the present invention may not be sufficiently obtained. Therefore, content of (B) component is 0.1-15 mass parts with respect to 100 mass parts of (A) component, 1-10 mass parts is preferable, and 1-5 mass parts is more preferable.

  The organic solvent contained in the liquid crystal aligning agent of this invention will not be specifically limited if (A) component and (B) component melt | dissolve uniformly. Specific examples thereof include N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, Examples include 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl sulfoxide, dimethyl sulfone, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, 3-methoxy-N, N-dimethylpropanamide and the like. You may use these 1 type or in mixture of 2 or more types. Moreover, even if it is a solvent which cannot melt | dissolve a polymer component uniformly by itself, if it is a range which a polymer does not precipitate, you may mix with said organic solvent.

  The liquid crystal aligning agent of this invention may contain the solvent for improving the coating-film uniformity at the time of apply | coating a liquid crystal aligning agent to a board | substrate other than the organic solvent for dissolving a polymer. As such a solvent, a solvent having a surface tension lower than that of the organic solvent is generally used. Specific examples thereof include ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 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, butyl cellosolve acetate, di Propylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl ester, lactic acid Isoamyl ester, and the like. Two or more of these solvents may be used in combination.

  In the liquid crystal aligning agent of the present invention, in addition to the above, as long as the effects of the present invention are not impaired, the polymer other than the polymer of the component (A) and the component (B), the dielectric constant of the liquid crystal aligning film, Dielectrics or conductive materials for the purpose of changing electrical properties such as conductivity, silane coupling agents for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate, and the hardness and density of the film when it is made into a liquid crystal alignment film A crosslinkable compound for the purpose of increasing, and an imidization accelerator for the purpose of efficiently proceeding imidization of the polyamic acid may be added when the coating film is baked.

<Liquid crystal alignment film>
The liquid crystal alignment film of the present invention is a coating film obtained by applying a liquid crystal aligning agent to a substrate, drying and baking, and can be obtained by irradiating this coating film surface with radiation polarized almost linearly.
The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, a silicon nitride substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like can be used. From the viewpoint of simplification of the process, it is preferable to use a substrate on which an ITO electrode or the like is formed. Further, in the reflection type liquid crystal display element, an opaque material such as a silicon wafer can be used as long as the substrate is only on one side, and in this case, a material that reflects light such as aluminum can be used. Examples of the method for applying the liquid crystal aligning agent of the present invention include a spin coating method, a printing method, and an ink jet method.
Arbitrary temperature and time can be selected for the drying and baking steps after applying the liquid crystal aligning agent of the present invention. Usually, in order to sufficiently remove the organic solvent contained, the organic solvent is dried at 50 ° C. to 120 ° C. for 1 minute to 10 minutes, and then baked at 150 ° C. to 300 ° C. for 5 minutes to 120 minutes. Although the thickness of the coating film after baking is not specifically limited, Since the reliability of a liquid crystal display element may fall when too thin, it is 5-300 nm, Preferably it is 10-200 nm.
The liquid crystal aligning agent of the present invention is particularly useful when used in a photo-alignment treatment method.

As a specific example of the photo-alignment treatment method, there is a method in which the surface of the coating film is irradiated with radiation polarized in a certain direction, and in some cases, a heat treatment is further performed at a temperature of 150 to 250 ° C. to impart liquid crystal alignment ability. Can be mentioned. As the wavelength of radiation, ultraviolet rays and visible rays having a wavelength of 100 nm to 800 nm can be used. Among these, ultraviolet rays having a wavelength of 100 nm to 400 nm are preferable, and those having a wavelength of 200 nm to 400 nm are particularly preferable. Moreover, in order to improve liquid crystal orientation, you may irradiate a radiation, heating a coating-film board | substrate at 50-250 degreeC. Dose of the radiation is preferably in the range of 1~10,000mJ / cm ^2, and particularly preferably in the range of 100~5,000mJ / cm ^2.
In order to induce reorientation of the component (B), it is preferable to perform heat treatment at a temperature of 150 to 250 ° C. after irradiation with polarized ultraviolet rays, and to perform a heat treatment at a temperature of 200 to 250 ° C. More preferred.

<Liquid crystal display element>
The liquid crystal display element of the present invention is a liquid crystal display element obtained by obtaining a substrate with a liquid crystal alignment film from the liquid crystal aligning agent of the present invention by the above-described method, performing an alignment treatment, and then preparing a liquid crystal cell by a known method. It is.
The manufacturing method of a liquid crystal cell is not specifically limited. For example, a pair of substrates on which a liquid crystal alignment film is formed are placed with a liquid crystal alignment film surface inside, preferably with a spacer of 1 to 30 μm, more preferably 2 to 10 μm. Is generally sealed with a sealant and sealed by injecting liquid crystal. The method for enclosing the liquid crystal is not particularly limited, and examples thereof include a vacuum method of injecting liquid crystal after reducing the pressure inside the produced liquid crystal cell, and a dropping method of sealing after dropping the liquid crystal.

［粘度］
合成例において、ポリアミック酸エステル及びポリアミック酸溶液の粘度は、Ｅ型粘度計ＴＶＥ−２２Ｈ（東機産業社製）を用い、サンプル量１．１ｍＬ、コーンロータＴＥ−１（１°３４’、Ｒ２４）、温度２５℃で測定した。The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. In addition, the symbol of the compound used by the present Example and the comparative example, and the measuring method of each characteristic are as follows.
NMP: N-methyl-2-pyrrolidone BCS: butyl cellosolve GBL: γ-butyrolactone AIBN: 2,2′-azobisisobutyronitrile DA-1: the following formula (DA-1)
DA-2: Formula (DA-2) below
MA1: The following formula (MA-1)

[viscosity]
In the synthesis example, the viscosity of the polyamic acid ester and the polyamic acid solution is an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), sample amount 1.1 mL, cone rotor TE-1 (1 ° 34 ′, R24). ), Measured at a temperature of 25 ° C.

[Molecular weight]
The molecular weight of the polyamic acid ester is measured by a GPC (normal temperature gel permeation chromatography) apparatus, and is a number average molecular weight (hereinafter also referred to as Mn) and a weight average molecular weight (hereinafter also referred to as Mw) as polyethylene glycol and polyethylene oxide equivalent values. ) Was calculated.
GPC device: manufactured by Shodex (GPC-101)
Column: manufactured by Shodex (series of KD803 and KD805)
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 calibration curve: TSK standard polyethylene oxide (weight average molecular weight (Mw) of about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polymer laboratory Polyethylene glycol manufactured by the company (peak top molecular weight (Mp) of about 12,000, 4,000, 1,000). In order to avoid the overlapping of peaks, the measurement was performed by mixing four types of 900,000, 100,000, 12,000, and 1,000, and three types of 150,000, 30,000, and 4,000. Two samples of mixed samples are measured separately.

[AC drive burn-in of FFS drive liquid crystal cell]
On a glass substrate, an ITO electrode having a thickness of 50 nm as an electrode in the first layer, a silicon nitride having a thickness of 500 nm as an insulating film in the second layer, and a comb-like shape as an electrode in the third layer Spin coating is applied to a glass substrate on which a fringe field switching (hereinafter referred to as FFS) driving electrode having ITO electrodes (electrode width: 3 μm, electrode interval: 6 μm, electrode height: 50 nm) is formed. A liquid crystal aligning agent was applied. After drying on an 80 ° C. hot plate for 5 minutes, baking was performed in a hot air circulation oven at 250 ° C. for 60 minutes to form a coating film having a thickness of 100 nm. This coating film surface was irradiated with 254 nm ultraviolet light through a polarizing plate to obtain a substrate with a liquid crystal alignment film. In addition, a coating film was similarly formed on a glass substrate having a columnar spacer having a height of 4 μm on which no electrode was formed as a counter substrate, and an orientation treatment was performed.

The two substrates are combined as a set, a sealant is printed on the substrate, and the other substrate is bonded so that the liquid crystal alignment film faces and the alignment direction is 0 °, and then the sealant is added. An empty cell was produced by curing. Liquid crystal MLC-2041 (manufactured by Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS drive liquid crystal cell.
After measuring the VT characteristic (voltage-transmittance characteristic) of the FFS driving liquid crystal cell at a temperature of 58 ° C., a rectangular wave of ± 4 V / 120 Hz was applied for 4 hours. After 4 hours, the voltage was turned off and left at a temperature of 58 ° C. for 60 minutes, and then the VT characteristics were measured again to calculate the voltage difference (ΔV ₅₀ ) that gave a transmittance of 50% before and after the rectangular wave application. .

(Synthesis Example 1)
To a 3000 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 2394 g of NMP was added, and 196.34 g (1.00 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride was added. While stirring the slurry solution of tetracarboxylic dianhydride, 101.11 g (0.935 mol) of p-phenylenediamine was added, and NMP was further added so that the solid content concentration was 8% by mass. The solution was stirred for a time to obtain a polyamic acid (PAA-1) solution. The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 115 mPa · s.

(Synthesis Example 2)
To a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, take 5.73 g (20.0 mmol) of 1,5-bis (4-aminophenoxy) pentane, add 65.4 g of NMP, and send nitrogen. While stirring, the mixture was dissolved. While stirring this diamine solution, 4.19 g (19.2 mmol) of pyromellitic dianhydride was added, NMP was further added so that the solid content concentration was 12% by mass, and the mixture was stirred at room temperature for 24 hours to polyamic acid. A solution of (PAA-2) was obtained. The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 520 mPa · s.

(Synthesis Example 3)
In a 300 ml four-necked flask equipped with a stirrer, 5.42 g (19.2 mmol) of 2,5-bis (methoxycarbonyl) terephthalic acid was taken, 100 g of NMP was added, and the mixture was stirred and dissolved. Subsequently, 4.45 g (43.98 mmol) of triethylamine and 5.17 g (20.0 mmol) of 1,3-bis (4-aminophenoxy) propane were added and dissolved by stirring. While stirring this solution, 16.60 g of 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride (15 ± 2 wt% hydrate) was added. Further, 13.74 g of NMP was added and reacted for 4 hours under water cooling.

The obtained polyamic acid ester solution was poured into 872 g of 2-propanol with stirring, and the deposited precipitate was collected by filtration, washed with 290 g of 2-propanol five times, and dried to obtain a polyamic acid ester. A resin powder was obtained. The molecular weight of this polyamic acid ester was Mn = 13462 and Mw = 28462.
In a 50 ml Erlenmeyer flask, 1.08 g of the obtained polyamic acid ester resin powder was taken, 9.78 g of NMP was added, and the mixture was stirred and dissolved at room temperature for 24 hours to obtain a polyamic acid ester solution (PAE-1).

(Synthesis Example 4)
To a 1000 mL four-necked flask with a stirrer and a nitrogen inlet tube, 309 g of GBL was added, and 67.25 g (30.30 g) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added. 0 mmol) was added. Next, 487 g of NMP was added. While stirring the slurry solution of tetracarboxylic dianhydride, 31.14 g (28.80 mmol) of p-phenylenediamine was added, and NMP was further added so that the solid concentration was 10% by mass. The mixture was stirred for a time to obtain a polyamic acid (PAA-3) solution. The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 471 mPa · s.

(Synthesis Example 5)
6.43 g (59.46 mmol) of p-phenylenediamine, 2.49 g (10.49 mmol) of DA-1 were added to a 300 mL four-necked flask with a stirrer and a nitrogen inlet tube, and 195 g of NMP was added. And dissolved by stirring. While stirring this solution, 15.09 g (67.31 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and the solid content concentration became 10% by mass. NMP was added and stirred at room temperature for 24 hours to obtain a solution of polyamic acid (PAA-4). The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 230 mPa · s.

(Synthesis Example 6)
To a 300 mL four-necked flask with a stirrer and a nitrogen inlet tube, 11.93 g (39.98 mmol) of DA-2 was added, and 162 g of NMP was added and stirred to dissolve. While stirring this solution, 8.03 g (36.82 mmol) of pyromellitic dianhydride was added, NMP was further added so that the solid content concentration was 10% by mass, and the mixture was stirred at room temperature for 24 hours to polyamic acid ( A solution of PAA-5) was obtained. The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 108 mPa · s.

(Synthesis Example 7)
In a 300 ml four-necked flask equipped with a stirrer, 5.19 g (18.4 mmol) of 2,5-bis (methoxycarbonyl) terephthalic acid was taken, 107 g of NMP was added, and dissolved by stirring. Subsequently, 4.45 g (44.0 mmol) of triethylamine and 6.00 g (19.97 mmol) of 1,6-bis (4-aminophenoxy) hexane were added and dissolved by stirring. While stirring this solution, 16.88 g of (2,3-dihydroxy-2-thioxo-3-benzoxazoyl) phosphonic acid diphenyl was added, and 15 g of NMP was further added, followed by reaction for 4 hours under water cooling. The obtained polyamic acid ester solution was added to 614 g of 2-propanol with stirring, and the deposited precipitate was collected by filtration, then washed with 307 g of 2-propanol five times and dried to obtain a polyamic acid ester. A resin powder was obtained.
The molecular weight of this polyamic acid ester was Mn = 6286 and Mw = 17648.
In a 50 ml Erlenmeyer flask, 2.00 g of the obtained polyamic acid ester resin powder was taken, 18.04 g of NMP was added, and the mixture was stirred and dissolved at room temperature for 24 hours to obtain a polyamic acid ester solution (PAE-2).

(Synthesis Example 8)
In a 300 ml four-necked flask equipped with a stirrer, 5.19 g (18.4 mmol) of 2,5-bis (methoxycarbonyl) terephthalic acid was taken, 109 g of NMP was added, and dissolved by stirring. Subsequently, 4.45 g (44.0 mmol) of triethylamine and 6.28 g (19.97 mmol) of 1,7-bis (4-aminophenoxy) heptane were added and dissolved by stirring. While stirring this solution, 16.87 g of (2,3-dihydroxy-2-thioxo-3-benzoxazoyl) phosphonic acid diphenyl was added, and 15 g of NMP was further added, followed by reaction for 4 hours under water cooling. The obtained polyamic acid ester solution was poured into 629 g of 2-propanol while stirring, and the deposited precipitate was collected by filtration, washed with 314 g of 2-propanol five times, and dried to obtain a polyamic acid ester. A resin powder was obtained.
The molecular weight of this polyamic acid ester was Mn = 5004 and Mw = 17542.
In a 50 ml Erlenmeyer flask, 2.00 g of the obtained polyamic acid ester resin powder was taken, 18.02 g of NMP was added, and the mixture was stirred and dissolved at room temperature for 24 hours to obtain a polyamic acid ester solution (PAE-3).

(Synthesis Example 9)
In a 300 ml four-necked flask equipped with a stirrer, 5.19 g (18.4 mmol) of 2,5-bis (methoxycarbonyl) terephthalic acid was taken, 112 g of NMP was added, and dissolved by stirring. Subsequently, 4.45 g (44.0 mmol) of triethylamine and 6.56 g (19.97 mmol) of 1,8-bis (4-aminophenoxy) octane were added and dissolved by stirring. While stirring this solution, 16.87 g of (2,3-dihydroxy-2-thioxo-3-benzoxazoyl) phosphonic acid diphenyl was added, and 15 g of NMP was further added, followed by reaction for 4 hours under water cooling. The obtained polyamic acid ester solution was added to 642 g of 2-propanol with stirring, and the deposited precipitate was collected by filtration, then washed with 321 g of 2-propanol five times and dried to obtain a polyamic acid ester. A resin powder was obtained.
The molecular weight of this polyamic acid ester was Mn = 6319 and Mw = 17702.
In a 50 ml Erlenmeyer flask, 2.00 g of the obtained polyamic acid ester resin powder was taken, 18.01 g of NMP was added, and the mixture was stirred and dissolved at room temperature for 24 hours to obtain a polyamic acid ester solution (PAE-4).

(Synthesis Example 10)
In a 300 ml four-necked flask equipped with a stirrer, 12.41 g (35.0 mmol) of MA1 was added and 111.7 g of NMP was added and dissolved, followed by deaeration with a diaphragm pump for 6 minutes. Thereafter, 0.287 g (1.80 mmol) of AIBN was added, and deaeration was performed again for 6 minutes. Then, it was made to react at 60 degreeC for 30 hours, and the polymer solution (MA-1) of the methacrylate was obtained. This polymer had a number average molecular weight of 13,000 and a weight average molecular weight of 51,000.

(Example 1)
In a 20 ml sample tube containing a stirrer, 7.13 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 0.29 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 2; 4.60 g of NMP and 3.02 g of BCS were added and stirred for 30 minutes with a magnetic stirrer to obtain a liquid crystal aligning agent (A-1).
(Example 2)
In a 20 ml sample tube containing a stirrer, 3.95 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 0.19 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 2; 3.88 g of NMP, 2.00 g of BCS, and 0.02 g of 1-butylimidazole were added, and stirred for 30 minutes with a magnetic stirrer to obtain a liquid crystal aligning agent (A-2).

Example 3
In a 20 ml sample tube containing a stirrer, 3.79 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 0.37 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 2; 3.89 g of NMP, 2.00 g of BCS, and 0.02 g of 1-butylimidazole were added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-3).
Example 4
In a 20 ml sample tube containing a stirrer, 7.42 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 0.08 g of the polyamic acid ester solution (PAE-1) obtained in Synthesis Example 3 were used. Then, 4.53 g of NMP and 3.03 g of BCS were stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-4).
(Comparative Example 1)
To a 20 ml sample tube containing a stirrer, 4.16 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1, 3.82 g of NMP, and 2.0 g of BCS were added, and 30 times with a magnetic stirrer. The liquid crystal aligning agent (B-1) was obtained by stirring for minutes.

(Example 5)
After filtering the liquid crystal aligning agent (A-1) obtained in Example 1 with a 1.0 μm filter, an ITO electrode having a film thickness of 50 nm as a first layer is insulated on a glass substrate as a second layer. Glass on which FFS driving electrodes having comb-like ITO electrodes (electrode width: 3 μm, electrode interval: 6 μm, electrode height: 50 nm) are formed as the third layer, silicon nitride having a thickness of 500 nm as a film The substrate was applied by spin coating. After drying on an 80 ° C. hot plate for 5 minutes, baking was performed in a hot air circulation oven at 230 ° C. for 15 minutes to form a coating film having a thickness of 100 nm. The surface of the coating film was irradiated with 1500 mJ / cm ^{2 of} 254 nm ultraviolet light through a polarizing plate, and further heated in a hot air circulation oven at 230 ° C. for 30 minutes to obtain a substrate with a liquid crystal alignment film. Further, a coating film was similarly formed on a glass substrate having a columnar spacer having a height of 4 μm on which no electrode was formed as a counter substrate, and an orientation treatment was performed.
The two substrates are combined as a set, a sealant is printed on the substrate, and the other substrate is bonded so that the liquid crystal alignment film faces and the alignment direction is 0 °, and then the sealant is added. An empty cell was produced by curing. Liquid crystal MLC-2041 (manufactured by Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS drive liquid crystal cell.
As a result of evaluating the AC drive burn-in characteristics of this FFS drive liquid crystal cell, ΔV ₅₀ was 1.8 mV.

(Example 6)
An FFS drive liquid crystal cell was produced in the same manner as in Example 5 except that the liquid crystal aligning agent (A-2) obtained in Example 2 was used. As a result of evaluating the AC drive burn-in characteristics of this FFS drive liquid crystal cell, ΔV ₅₀ was 1.3 mV.
(Example 7)
An FFS drive liquid crystal cell was produced in the same manner as in Example 5 except that the liquid crystal aligning agent (A-3) obtained in Example 3 was used. As a result of evaluating the AC drive burn-in characteristics of this FFS drive liquid crystal cell, ΔV ₅₀ was 1.2 mV.

(Example 8)
An FFS drive liquid crystal cell was produced in the same manner as in Example 5 except that the liquid crystal aligning agent (A-4) obtained in Example 4 was used. As a result of evaluating the AC drive burn-in characteristics of this FFS drive liquid crystal cell, ΔV ₅₀ was 1.1 mV.
(Comparative Example 2)
An FFS drive liquid crystal cell was produced in the same manner as in Example 6 except that the liquid crystal aligning agent (B-1) obtained in Comparative Example 1 was used. As a result of evaluating the AC drive burn-in characteristics of this FFS drive liquid crystal cell, ΔV ₅₀ was 5.0 mV.

Example 9
In a 50 ml sample tube containing a stirrer, 16.29 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 4, 0.45 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 2 and NMP 7.38 g of BCS, 6.05 g of BCS, and 0.23 g of N-α- (9-fluorenylmethoxycarbonyl) -N-τ-t-butoxycarbonyl-L-histidine as an imidization accelerator, The mixture was stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-5).

(Example 10)
In a 50 ml sample tube containing a stir bar, 10.79 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 4 and 0.31 g of the polyamic acid solution (PAA-5) obtained in Synthesis Example 6 were added. G, 6.05 g of BCS, and N-α- (9-fluorenylmethoxycarbonyl) -N-τ-t-butoxycarbonyl-L-histidine as an imidization accelerator were added for 30 minutes with a magnetic stirrer. The liquid crystal aligning agent (A-6) was obtained by stirring.

(Example 11)
In a 50 ml sample tube containing a stirrer, 10.90 g of the polyamic acid solution (PAA-4) obtained in Synthesis Example 5 and 0.10 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 2 and NMP 5.08 g, 4.26 g BCS, and 0.15 g N-α- (9-fluorenylmethoxycarbonyl) -N-τ-t-butoxycarbonyl-L-histidine as an imidization accelerator, The liquid crystal aligning agent (A-7) was obtained by stirring for 30 minutes with a magnetic stirrer.

(Example 12)
In a 20 ml sample tube containing a stirrer, 7.45 g of the polyamic acid solution (PAA-4) obtained in Synthesis Example 5 and 0.08 g of the polyamic acid ester solution (PAE-2) obtained in Synthesis Example 7 were obtained. 4.39 g of NMP, 3.02 g of BCS, and 0.08 g of N-α- (9-fluorenylmethoxycarbonyl) -N-τ-t-butoxycarbonyl-L-histidine as an imidization accelerator were added. And it stirred for 30 minutes with the magnetic stirrer, and obtained the liquid crystal aligning agent (A-8).

(Example 13)
In a 20 ml sample tube containing a stir bar, 7.43 g of the polyamic acid solution (PAA-4) obtained in Synthesis Example 5 and 0.08 g of the polyamic acid ester solution (PAE-3) obtained in Synthesis Example 8 were obtained. 4.38 g of NMP, 3.11 g of BCS, and 0.08 g of N-α- (9-fluorenylmethoxycarbonyl) -N-τ-t-butoxycarbonyl-L-histidine as an imidization accelerator were added. And it stirred for 30 minutes with the magnetic stirrer, and obtained the liquid crystal aligning agent (A-9).

(Example 14)
In a 20 ml sample tube containing a stirrer, 7.43 g of the polyamic acid solution (PAA-4) obtained in Synthesis Example 5 and 0.08 g of the polyamic acid ester solution (PAE-4) obtained in Synthesis Example 9 were obtained. 4.35 g of NMP, 3.02 g of BCS, and 0.08 g of N-α- (9-fluorenylmethoxycarbonyl) -N-τ-t-butoxycarbonyl-L-histidine as an imidization accelerator were added. And it stirred for 30 minutes with the magnetic stirrer, and obtained the liquid crystal aligning agent (A-10).

(Example 15)
An FFS drive liquid crystal cell was produced in the same manner as in Example 5 except that the liquid crystal aligning agent (A-5) obtained in Example 9 was used and 254 nm ultraviolet rays were irradiated at 500 mJ / cm ² . As a result of evaluating the AC drive burn-in characteristics of this FFS drive liquid crystal cell, ΔV ₅₀ was 0.8 mV.
(Example 16)
An FFS drive liquid crystal cell was produced in the same manner as in Example 5 except that the liquid crystal aligning agent (A-6) obtained in Example 10 was used and 254 nm ultraviolet rays were irradiated at 500 mJ / cm ² . As a result of evaluating the AC drive burn-in characteristics of this FFS drive liquid crystal cell, ΔV ₅₀ was 1.0 mV.

(Example 17)
An FFS drive liquid crystal cell was produced in the same manner as in Example 5 except that the liquid crystal aligning agent (A-7) obtained in Example 11 was used and 254 nm ultraviolet rays were irradiated at 500 mJ / cm ² . As a result of evaluating the AC drive burn-in characteristics of this FFS drive liquid crystal cell, ΔV ₅₀ was 0.8 mV.
(Example 18)
An FFS drive liquid crystal cell was produced in the same manner as in Example 5 except that the liquid crystal aligning agent (A-8) obtained in Example 12 was used and 254 nm ultraviolet rays were irradiated at 500 mJ / cm ² . As a result of evaluating the AC drive burn-in characteristics of this FFS drive liquid crystal cell, ΔV ₅₀ was 0.6 mV.

(Example 19)
An FFS drive liquid crystal cell was produced in the same manner as in Example 5 except that the liquid crystal aligning agent (A-9) obtained in Example 13 was used and 254 nm ultraviolet rays were irradiated at 500 mJ / cm ² . As a result of evaluating the AC drive burn-in characteristics of this FFS drive liquid crystal cell, ΔV ₅₀ was 1.1 mV.
(Example 20)
An FFS drive liquid crystal cell was produced in the same manner as in Example 5 except that the liquid crystal aligning agent (A-10) obtained in Example 14 was used and 254 nm ultraviolet rays were irradiated at 500 mJ / cm ² . As a result of evaluating the AC drive burn-in characteristics of this FFS drive liquid crystal cell, ΔV ₅₀ was 1.1 mV.

(Example 21)
In a 50 ml sample tube containing a stirrer, 12.44 g of the polymer solution of methacrylate (M-1) obtained in Synthesis Example 10 and 0.32 g of the polyamic acid solution (A-2) obtained in Synthesis Example 2 were obtained. Then, 2.08 g of NMP and 6.19 g of BCS were added and stirred at room temperature for 5 hours to obtain a liquid crystal aligning agent (A-11).
(Example 22)
In a 50 ml sample tube containing a stirrer, 12.41 g of the polymer solution (M-1) of the methacrylate obtained in Synthesis Example 10 and 0.54 g of the polyamic acid solution (A-2) obtained in Synthesis Example 2 , 2.09 g of NMP and 6.20 g of BCS were added, and the mixture was stirred at room temperature for 5 hours to obtain a liquid crystal aligning agent (A-12).

(Comparative Example 3)
To a 50 ml sample tube containing a stir bar, 12.44 g of the polymer solution (M-1) obtained in Synthesis Example 10 and 2.05 g of NMP and 6.21 g of BCS were added, and 5 hours at room temperature. The mixture was stirred to obtain a liquid crystal aligning agent (B-2).

(Example 23)
Using the liquid crystal aligning agent (A-11) obtained in Example 21, a liquid crystal cell was prepared according to the procedure shown below. The board
A glass substrate having a size of 30 mm × 40 mm and a thickness of 0.7 mm and having a comb-like pixel electrode formed by patterning an ITO film is used. The pixel electrode has a comb-like shape configured by arranging a plurality of dog-shaped electrode elements whose central portion is bent. The width in the short direction of each electrode element is 10 μm, and the distance between the electrode elements is 20 μm. Since the pixel electrode forming each pixel is formed by arranging a plurality of bent-shaped electrode elements in the central portion, the shape of each pixel is not rectangular, but in the central portion like the electrode elements. It has a shape that bends and resembles a bold-faced koji. Each pixel is divided into upper and lower portions with a central bent portion as a boundary, and has a first region on the upper side of the bent portion and a second region on the lower side. When the first region and the second region of each pixel are compared, the formation directions of the electrode elements of the pixel electrodes constituting them are different.

  That is, when the alignment processing direction of the liquid crystal alignment film described later is used as a reference, the electrode element of the pixel electrode is formed to form an angle of + 15 ° (clockwise) in the first region of the pixel, and in the second region of the pixel. The electrode elements of the pixel electrode are formed so as to form an angle of −15 ° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotation operation (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode are mutually in the substrate plane. It is comprised so that it may become a reverse direction. The liquid crystal aligning agent (A-11) obtained in Example 21 was spin-coated on the prepared substrate with electrodes. Next, after drying for 90 seconds on an 80 ° C. hot plate, baking was performed for 30 minutes in a 160 ° C. hot air circulation oven to form a liquid crystal alignment film having a thickness of 100 nm.

Next, the coating film surface was irradiated with 313 nm ultraviolet rays through a polarizing plate at 500 mJ / cm ² and then heated in a hot air circulation oven at 160 ° C. to obtain a substrate with a liquid crystal alignment film. Further, a coating film was similarly formed on a glass substrate having a columnar spacer having a height of 4 μm on which no electrode was formed as a counter substrate, and an orientation treatment was performed. A sealant (XN-1500T manufactured by Kyoritsu Chemical Co., Ltd.) was printed on the liquid crystal alignment film of one substrate. Next, the other substrate was bonded so that the liquid crystal alignment film faces each other and the alignment direction was 0 °, and then the sealing agent was cured to produce an empty cell. A liquid crystal cell having a configuration of an IPS (In-Plane Switching) mode liquid crystal display element is injected into the empty cell by a reduced pressure injection method by injecting liquid crystal MLC-2041 (Merck Co., Ltd.), sealing the injection port. Obtained.

The liquid crystal cell for IPS mode obtained by the above method is installed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, the backlight is turned on with no voltage applied, and the transmitted light is transmitted. The arrangement angle of the liquid crystal cell was adjusted so that the luminance was minimized. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the pixel was darkest to the angle at which the first region was darkest was calculated as the initial orientation azimuth. Next, an AC voltage of 8 V _PP was applied at a frequency of 30 Hz in an oven at 60 ° C. for 168 hours. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left as it was at room temperature for 1 hour. After standing, the orientation azimuth angle was measured in the same manner, and the difference between the orientation azimuth angles before and after AC driving was calculated as an angle Δ (deg.). It can be judged that the smaller the difference in orientation orientation before and after AC driving, the better the AC driving image sticking characteristics. As a result, the difference in orientation azimuth angle before and after AC driving is the angle Δ (deg.). It was 0.5 °.

(Example 24)
An IPS drive liquid crystal cell was produced in the same manner as in Example 23 except that the liquid crystal aligning agent (A-12) obtained in Example 22 was used. As a result of evaluating the AC drive burn-in characteristics of this IPS drive liquid crystal cell in the same manner as in Example 23, the difference in orientation azimuth angle before and after AC drive is the angle Δ (deg.). It was 0.4 °.
(Comparative Example 4)
An IPS drive liquid crystal cell was produced in the same manner as in Example 23 except that the liquid crystal aligning agent (B-2) obtained in Comparative Example 3 was used. As a result of evaluating the AC drive burn-in characteristics of this IPS drive liquid crystal cell in the same manner as in Example 23, the difference in orientation azimuth angle before and after AC drive is the angle Δ (deg.). It was 1.7 °.

  The liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention reduces afterimages due to AC driving generated in an IPS driving type or FFS driving type liquid crystal display element, and because the residual charge accumulated by the DC voltage is quickly relaxed, It is particularly useful as a liquid crystal alignment film of an IPS driving method or an FFS driving method having excellent afterimage characteristics or a liquid crystal alignment film of a liquid crystal television.

  It should be noted that the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2011-171227 filed on August 4, 2011 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (17)

The following (A) component, (B) component, and an organic solvent are contained, Content of (B) component is 0.1-15 mass parts with respect to 100 mass parts of (A) component, It is characterized by the above-mentioned. Liquid crystal aligning agent.
Component (A): Irradiation with polarized radiation causes a reaction of photodecomposition, photodimerization, or photoisomerization to proceed in the same direction as the polarization direction or in a direction perpendicular to the polarization direction. One type or two or more types of polymers imparted with anisotropy.
(B) Component: A polymer containing a structure represented by the following formula (1).

(In Formula (1), W ₁ and W ₂ are each independently a divalent organic group having an aromatic group having 6 to 30 carbon atoms, and A has an alkylene group having 2 to 20 carbon atoms. It is a divalent organic group.)   The component (A) is one or two or more types of polymers that undergo a photolysis reaction when irradiated with polarized radiation and impart anisotropy in a direction perpendicular to the polarization direction. Item 2. A liquid crystal aligning agent according to Item 1. The component (A) is at least one polymer selected from the group consisting of a polyimide precursor containing a structural unit represented by the following formula (2) and an imidized polymer of the polyimide precursor. Or the liquid crystal aligning agent of 2.

(X ₁ is at least one selected from the group consisting of structures represented by the following formulas (X1-1) to (X1-9), Y ₁ is a divalent organic group, and R ₁ is It is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

(R ₃ , R ₄ , R ₅ , and R ₆ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group, or a phenyl group. is there.)   (A) From the group which a component consists of a polyimide precursor which contains 60 mol% or more of structural units represented by said Formula (2) with respect to 1 mol of all the structural units, and the imidation polymer of this polyimide precursor. The liquid crystal aligning agent according to claim 3, which is at least one selected. 5. The liquid crystal aligning agent according to claim 3, wherein, in the formula (2), X ₁ is at least one selected from the group consisting of a structure represented by the formula (X1-1). The formula (2), wherein X ₁ is at least one selected from the group consisting of structures represented by the following formulas (X1-10) to (X1-11). Liquid crystal aligning agent.

In the above formula (2), the liquid crystal alignment agent according to any one of claims 3 to 6 is at least one Y ₁ is selected from the group consisting of structures represented by the following formulas (4) and (5).

(Z ₁ is a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 10 carbon atoms.) The liquid crystal aligning agent according to claim 7, wherein Y ₁ in the formula (2) has a structure represented by the formula (4). The component (B) is at least one polymer selected from the group consisting of a polyimide precursor having a structural unit represented by the following formula (3) and an imidized polymer of the polyimide precursor. The liquid crystal aligning agent in any one of 8.

(X ₂ is a tetravalent organic group having an aromatic group having 6 to 20 carbon atoms and having a bond in the aromatic group, and Y ₂ is represented by the following formulas (Y2-1) to (Y2-2). At least one divalent organic group selected from the group consisting of: A ₁ and A ₂ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent; An alkenyl group and an alkynyl group, and R ₂ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

(A ₃ is a divalent organic group having an alkylene group having 2 to 20 carbon atoms. In Formula (Y2-2), A ₄ is a single bond, —O—, —S—, —NR ₁₂ —, An ester bond, an amide bond, a thioester bond, a urea bond, a carbonate bond, and a carbamate bond; R ₁₂ is a hydrogen atom, a methyl group, or a t-butoxycarbonyl group; and A ₅ is an alkylene group having 2 to 10 carbon atoms. .)   The component (B) is selected from the group consisting of a polyimide precursor containing 60 mol% or more of the structural unit represented by the above formula (3) with respect to 1 mol of all structural units and an imidized polymer of the polyimide precursor. The liquid crystal aligning agent according to claim 9, which is at least one kind of polymer. The liquid crystal aligning agent according to claim 9 or 10 _{X 2} is at least one selected from the group consisting of structures represented by the following formula (X2-1) ~ (X2-3) of formula (3).

The liquid crystal aligning agent according to claim 11, wherein X _{2 in the} formula (3) is the formula (X2-1). The liquid crystal alignment according to claim 9, wherein Y _{2 in the} formula (3) is at least one selected from the group consisting of structures represented by the following formulas (Y2-3) to (Y2-12). Agent.

(In formulas (Y2-10) and (Y2-11), R each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, which may be the same or different.)   The liquid crystal aligning film obtained by apply | coating and baking the liquid crystal aligning agent in any one of Claims 1-13.   The liquid crystal aligning film obtained by apply | coating and baking the liquid crystal aligning agent in any one of Claims 1-13, and also irradiating the polarized radiation.   The liquid crystal aligning film obtained by apply | coating and baking the liquid crystal aligning agent in any one of Claims 1-13, irradiating with the polarized radiation, and heating at 150 to 300 degreeC.   The liquid crystal display element which comprises the liquid crystal aligning film in any one of Claims 14-16.