JP4539836B2 - Liquid crystal aligning agent and horizontal electric field type liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent for a horizontal electric field mode and a horizontal electric field mode liquid crystal display element. More specifically, the liquid crystal aligning agent for a horizontal electric field method that provides a liquid crystal alignment film for a horizontal electric field method having a small charge accumulation amount and a high voltage holding ratio and excellent rubbing resistance, and the liquid crystal alignment film for the horizontal electric field method The present invention relates to a horizontal electric field mode liquid crystal display element.

  Currently, as a liquid crystal display element, a liquid crystal alignment film made of polyamic acid, polyimide, or the like is formed on the surface of a substrate on which a transparent conductive film is provided to form a liquid crystal display element substrate. A nematic liquid crystal layer having positive dielectric anisotropy is formed in a cell having a sandwich structure so that the major axis of the liquid crystal molecules is continuously twisted 90 degrees from one substrate to the other. A TN type liquid crystal display element having a so-called TN type (Twisted Nematic) liquid crystal cell is known.

  Further, STN (Super Twisted Nematic) type liquid crystal display elements and vertical alignment type liquid crystal display elements, which have a higher contrast than the TN type liquid crystal display elements and have less viewing angle dependency, have been developed. This STN type liquid crystal display element uses nematic liquid crystal blended with a chiral agent which is an optically active substance as liquid crystal, and the major axis of liquid crystal molecules is continuously twisted over 180 degrees between substrates. The birefringence effect generated by the above is utilized.

  In recent years, the development of new liquid crystal display elements has also been active, and as one of them, two electrodes for driving a liquid crystal are arranged in a comb shape on one substrate, and an electric field parallel to the substrate surface is arranged. A lateral electric field type liquid crystal display element that generates liquid crystal and controls liquid crystal molecules has been proposed (see Patent Document 1). This element is generally called an in-plane switching type (IPS type), and is known for its excellent wide viewing angle characteristics. Recently, an optical compensation film is used to further improve the wide viewing angle characteristics, so that it is possible to obtain a wide viewing angle comparable to that of a cathode ray tube without tone reversal or color change.

  On the other hand, in the horizontal electric field type liquid crystal display element, in order to improve the response speed, the dielectric anisotropy of liquid crystal molecules that play a role of switching in the liquid crystal display element is improved. As the dielectric anisotropy of the liquid crystal molecules increases, the content of ionic impurities in the liquid crystal display element increases, and this accumulates as residual charges due to the application of an asymmetric voltage for driving the element. . As a result, there is a problem that the accumulated residual charge disturbs the alignment of the liquid crystal or causes burn-in or afterimage. In addition, this charge accumulation causes a decrease in the voltage holding ratio, which causes flickering, thereby deteriorating the quality of the display element.

  Also, the horizontal electric field type liquid crystal alignment film is generally subjected to a rubbing treatment after the coating film is formed. However, in the horizontal electric field type liquid crystal display element, the unevenness of the electrodes arranged in a comb shape is large, and the alignment is In order to increase the regulation force, it is necessary to perform a strong rubbing process, and the rubbing process is likely to cause abrasion as compared with a conventional liquid crystal display element. The scratches and scraps on the surface of the coating film due to this shaving have caused a problem of lowering the display quality.

In the past, Patent Document 2, Patent Document 3 and Patent Document 4 have been proposed as liquid crystal aligning agent film materials for the transverse electric field method for the above problem. At present, however, due to the increase in the screen size of liquid crystal display elements and the increase in definition for further improvement in display quality, the existing technology has become insufficient for solving problems, and improvements in liquid crystal alignment film materials have been demanded.
Japanese Patent Laid-Open No. 7-261181 JP 2002-131751 A WO02 / 33481 JP 2004-206091 A

  An object of the present invention is to provide a high-quality lateral electric field liquid crystal display element free from burn-in and afterimages by suppressing charge accumulation and a decrease in voltage holding ratio.

  Another object of the present invention is to provide a liquid crystal aligning agent capable of providing the transverse electric field type liquid crystal display device of the present invention having excellent characteristics.

  Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the object of the present invention is firstly as follows:
A polyamic acid polymer containing a repeating unit represented by the following formula (I-1)

（ここでＷ^１はテトラカルボン酸から４つのカルボキシル基を除去した４価の有機残基を示しそしてＲ^１はジアミンから２つのアミノ基を除去した２価の有機残基を示す。）
および下記式（Ｉ−２）で表されるイミド繰返し単位を含有してなるポリイミド重合体

(W ¹ represents a tetravalent organic residue obtained by removing four carboxyl groups from tetracarboxylic acid, and R ¹ represents a divalent organic residue obtained by removing two amino groups from diamine.)
And a polyimide polymer containing an imide repeating unit represented by the following formula (I-2)

（ここでＷ^２はテトラカルボン酸から４つのカルボキシル基を除去した４価の有機残基を示しそしてＲ^２はジアミンから２つのアミノ基を除去した２価の有機残基を示す。）
を含有する液晶配向剤であって、上記ポリアミック酸は、式（Ｉ−１）で表わされる繰返し単位の合計を基準にして、二価の有機残基であるＲ^１が下記式（ＩＩ）

(W ² represents a tetravalent organic residue obtained by removing four carboxyl groups from tetracarboxylic acid, and R ² represents a divalent organic residue obtained by removing two amino groups from diamine.)
The polyamic acid is a divalent organic residue R ¹ represented by the following formula (II) based on the total number of repeating units represented by the formula (I-1).

（ここで、Ｒ^３，Ｒ^４，Ｒ^５およびＲ^６は、相互独立に、水素原子または１価の有機基を示す。）
で示される式（Ｉ−１）で表わされる繰返し単位を少なくとも５０モル％含有し、かつ４価の有機残基であるＷ^１が下記式（ＩＩＩ）

(Here, R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or a monovalent organic group.)
W ¹ which is a tetravalent organic residue containing at least 50 mol% of the repeating unit represented by the formula (I-1) represented by the formula (III)

（ここで、Ｒ^７，Ｒ^８，Ｒ^９およびＲ^１０は、相互独立に、水素原子または１価の有機基を示す。）
で示される式（Ｉ−１）で表わされる繰返し単位を少なくとも３０モル％と、下記式

（ここで、Ｒ ^１１ は、水素原子または１価の有機基を示す。）
のそれぞれで表わされる４価の有機残基よりなる群から選ばれる少なくとも一種である式（Ｉ−１）で表わされる繰返し単位を含有しそして上記ポリアミック酸重合体を上記ポリアミック酸重合体と上記ポリイミド重合体の合計を基準にして４０〜８９重量％含有することを特徴とする横電界方式液晶表示素子用液晶配向剤によって達成される。

(Here, R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a monovalent organic group.)
At least 30 mol% of the repeating unit represented by the formula (I-1) represented by the formula:

(Here, R ¹¹ represents a hydrogen atom or a monovalent organic group.)
A repeating unit represented by the formula (I-1) which is at least one selected from the group consisting of tetravalent organic residues represented by each of the above and the polyamic acid polymer, the polyamic acid polymer and the polyimide This is achieved by a liquid crystal aligning agent for a horizontal electric field mode liquid crystal display element characterized by containing 40 to 89% by weight based on the total amount of polymers.

According to the liquid crystal aligning agent of the present invention, when a liquid crystal aligning film is obtained, a liquid crystal aligning film suitable for a lateral electric field type liquid crystal display element having high reliability can be obtained regardless of process conditions such as film thickness and rubbing conditions. .
Furthermore, the lateral electric field type liquid crystal display element having an alignment film formed using the liquid crystal aligning agent of the present invention is excellent in rubbing resistance and electrical characteristics and has a very high display quality, and can be used effectively in various devices. For example, it can be used for display devices such as a desk calculator, a wristwatch, a table clock, a counting display board, a word processor, a personal computer, a mobile phone, and a liquid crystal television.

  Hereinafter, the present invention will be described in detail. The polyamic acid used in the liquid crystal aligning agent for horizontal electric field system of the present invention (hereinafter also referred to as “liquid crystal aligning agent of the present invention”) is obtained by reacting a tetracarboxylic dianhydride and a diamine compound in an organic solvent. It is done. At this time, the following formula (II ′) which gives a divalent organic residue represented by the above formula (II) as a diamine compound

ここで、Ｒ^３，Ｒ^４，Ｒ^５およびＲ^６の定義は上記式（ＩＩ）に同じである、
で表わされるジアミンを全ジアミン基準で５０モル％以上およびテトラカルボン酸二無水物として前記式（ＩＩＩ）で示される４価の有機残基かを与える下記式（ＩＩＩ’）

Here, the definitions of R ³ , R ⁴ , R ⁵ and R ⁶ are the same as those in the above formula (II).
Wherein the diamine represented by the formula (III ′) gives 50 mol% or more based on the total diamine and the tetracarboxylic dianhydride is a tetravalent organic residue represented by the formula (III).

ここで、Ｒ^７，Ｒ^８，Ｒ^９およびＲ^１０の定義は上記式（ＩＩＩ）に同じである、
で表わされるテトラカルボン酸二無水物を全テトラカルボン酸二無水物基準で３０モル％以上使用する。本発明の液晶配向剤に用いられるポリイミドは、通常、ポリアミック酸を脱水閉環して得ることができる。以下、本発明に用いられるポリアミック酸、ポリイミドの製法について述べる。

Here, the definitions of R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are the same as those in the above formula (III).
The tetracarboxylic dianhydride represented by is used in an amount of 30 mol% or more based on the total tetracarboxylic dianhydride. The polyimide used for the liquid crystal aligning agent of the present invention can usually be obtained by dehydrating and ring-closing polyamic acid. Hereafter, the manufacturing method of the polyamic acid and polyimide used for this invention is described.

[Tetracarboxylic dianhydride]
Examples of the tetracarboxylic dianhydride used for the production of the polyamic acid polymer include cyclobutane tetracarboxylic dianhydride represented by the above formula (III ′), such as 1,2,3,4-cyclobutanetetracarboxylic acid. Dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-diethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1, 3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-diethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4- Tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride can be mentioned as a preferable one. Examples of other tetracarboxylic dianhydrides other than the above cyclobutanetetracarboxylic dianhydride include, for example, butanetetracarboxylic dianhydride and 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic acid. Dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetracarboxylic acid Acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 3,5,6-tricarboxynorbornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofuran tetracarboxylic acid dianhydride 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 3, 3a, 4, 5, 9b Hexahydro-5-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b- Hexahydro-5-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b- Hexahydro-7-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b- Hexahydro-7-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b- Hexahydro-8-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -fur 1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c]- Furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5,8-dimethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c ] -Furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2,2,2]- Aliphatic and alicyclic tetracarboxylic dianhydrides such as oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, compounds represented by the following formulas (VI) and (VII);

（式中、Ｒ^ａおよびＲ^ｃは、芳香環を有する２価の有機基を示し、Ｒ^ｂおよびＲ^ｄは、水素原子またはアルキル基を示し、複数存在するＲ^ｂおよびＲ^ｄは、それぞれ同一でも異なっていてもよい。）

(In the formula, R ^a and R ^c represent a divalent organic group having an aromatic ring, R ^b and R ^d represent a hydrogen atom or an alkyl group, and a plurality of R ^b and R ^d are the same. But it may be different.)

  Pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5, 8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4'-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ', 4,4'-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4′-bis ( 3,4-dicarboxyphenoxy) diph Nylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidene diphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenyl Phosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether Dianhydride, bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride, ethylene glycol-bis (anhydrotrimellitate), propylene glycol-bis (anhydrotrimellitate), 1,4- Butanediol-bis (anhydrotrimellitate), 1,6-hexanediol-bis (anhydrotrimellitate), 1,8-o Mention may be made of aromatic tetracarboxylic dianhydrides such as kutandiol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate). These may be used alone or in combination of two or more.

Of these, the tetracarboxylic dianhydrides giving W ¹ of formula (I-1) are 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3. , 4-Cyclobutanetetracarboxylic dianhydride, 1,2-diethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic Acid dianhydride, 1,3-diethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, it contains at least one kind of tetracarboxylic acid dianhydride least 30 mol% are selected from. More preferably at least 60 mol% from the viewpoint of Japanese propensity, more preferably not less than 80 mol%. As the other tetracarboxylic dianhydride, in order to obtain a sufficient effect of the liquid crystal aligning agent of the present invention, the tetracarboxylic acid dianhydride of alicyclic system Ru is used. That is, as tetracarboxylic dianhydride which gives W ¹ of formula (I-1),

で表わされる４個の有機残基を与える１,２,３,４−シクロペンタンテトラカルボン酸二無水物、同様に下記式

1,2,3,4-cyclopentanetetracarboxylic dianhydride which gives four organic residues represented by

で表わされる４個の有機残基を与える１,２,４,５−シクロヘキサンテトラカルボン酸二無水物、同様に下記式

1,2,4,5-cyclohexanetetracarboxylic dianhydride which gives four organic residues represented by

で表わされる４個の有機残基を与える２,３,５−トリカルボキシシクロペンチル酢酸二無水物および同様に下記式

2,3,5-tricarboxycyclopentyl acetic acid dianhydride giving four organic residues represented by the formula

ここで、Ｒ^１１は水素原子または１価の有機基である、
で表わされる４価の有機残基を与える１，３，３ａ，４，５，９ｂ−ヘキサヒドロ−８−エチル−５（テトラヒドロ−２，５−ジオキソ−３−フラニル）−ナフト［１，２−ｃ］−フラン−１，３−ジオンから選ばれる少なくとも一種のテトラカルボン酸二無水物が用いられる。

Here, R ¹¹ is a hydrogen atom or a monovalent organic group.
1,3,3a, 4,5,9b-Hexahydro-8-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2- c] At least one tetracarboxylic dianhydride selected from -furan-1,3-dione is used .

Further, even if the above formula tetracarboxylic dianhydride which can be used in a polyimide polymer having a structure represented by W ² of (I-2), can be the same as the above. 2,3,5-Tricarboxycyclopentylacetic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3,3a, 4,5,9b- from the viewpoint of solubility and coatability Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b At least one tetracarboxylic acid selected from: -hexahydro-8-ethyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione It is preferred to use anhydrides, especially 2,3,5-tricarboxycyclopentylacetic acid dianhydride and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5- Dioxo-3-furanyl) -naphtho [1,2-c]- Lan-1,3-dione and / or 1,3,3a, 4,5,9b-hexahydro-8-ethyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2- The combination of c] -furan-1,3-dione is particularly preferred. In this combination, it is more preferable to use the latter tetracarboxylic dianhydride at a ratio of 50 mol% or more.

[Diamine compound]
Examples of the diamine compound that can be used in the production of the polyamic acid polymer include diamines represented by the formula (II ′), such as p-phenylenediamine, 2-methyl-1,4-phenylenediamine, and 2-ethyl-1. , 4-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, 2,5-diethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine It can be mentioned as a preferable one.

  Examples of the diamine other than the above diamine include m-phenylenediamine, 2,5-dimethyl-1,3-phenylenediamine, 2,5-diethyl-1,3-phenylenediamine, and 4,4′-diamino. Diphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino Benzanilide, 4,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4′-diaminobiphenyl, 5-amino-1- (4′-aminophenyl) -1,3, 3-trimethylindane, 6-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 3,4′-diaminodiphe Nyl ether, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [ 4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4 -Bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10- Hydroanthracene, 2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 4,4'-methylene-bis (2-chloro) Nilin) 2,2 ′, 5,5′-tetrachloro-4,4′-diaminobiphenyl, 2,2′-dichloro-4,4′-diamino-5,5′-dimethoxybiphenyl, 3,3 ′ -Dimethoxy-4,4'-diaminobiphenyl, 1,4,4 '-(p-phenyleneisopropylidene) bisaniline, 4,4'-(m-phenyleneisopropylidene) bisaniline, 2,2'-bis [4- (4-Amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino- Aromatic diamines such as 2-trifluoromethyl) phenoxy] -octafluorobiphenyl;

1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 2,4-diaminocyclohexane, isophorone diamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoin danylene dimethylene diamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenedimethyl diamine, 4 Aliphatic and cycloaliphatic diamines such as 4,4'-methylenebis (cyclohexylamine);

  2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino-2,4 -Dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,3 , 5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl -S-triazine, 2,4-diamino-1,3,5-triazine, 4,6-diamino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6-diaminopurine 5,6-diamino-1,3 Dimethyluracil, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6-phenylphenanthridine, 1,4-diaminopiperazine, 3, , 6-diaminoacridine, bis (4-aminophenyl) phenylamine, and a compound represented by the following formula (VIII) have two primary amino groups and a nitrogen atom other than the primary amino group in the molecule Diamines;

（式中、Ｘは、ピリジン、ピリミジン、トリアジン、ピペリジンおよびピペラジンから選ばれる窒素原子を含む環構造を有する１価の有機基を示し、Ｒ^ｅは２価の有機基を示す。）
下記式（ＩＸ）で表されるジアミノオルガノシロキサン；

(In the formula, X, pyridine, shows pyrimidine, triazine, a monovalent organic group having a ring structure containing a nitrogen atom selected from piperidine and piperazine, R ^e represents a divalent organic group.)
Diaminoorganosiloxane represented by the following formula (IX);

（式中、Ｒ^ｆは、炭素数１〜１２の炭化水素基を示し、複数存在するＲ^ｆは、それぞれ同一でも異なっていてもよく、ｐは１〜３の整数であり、ｑは１〜２０の整数である。）
下記式（Ｘ）〜（ＸＩ）

(In the formula, R ^f represents a hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ^f may be the same or different, p is an integer of 1 to 3, and q is 1 to 1; (It is an integer of 20.)
Formulas (X) to (XI) below

（式中、ｒは２〜１２の整数であり、ｓは１〜５の整数である。）
で表される化合物などを挙げられる。これらのジアミン化合物は、単独でまたは２種以上組み合わせて用いることができる。

(In the formula, r is an integer of 2 to 12, and s is an integer of 1 to 5.)
The compound etc. which are represented by these are mentioned. These diamine compounds can be used alone or in combination of two or more.

  Among these, p-phenylenediamine, 2-methyl-1,4-phenylenediamine, 2-ethyl-1,4-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, 2,5-diethyl- It is preferable to contain 50 mol% or more of at least one diamine selected from 1,4-phenylenediamine and 2,3,5,6-tetramethyl-1,4-phenylenediamine, and 70 mol% or more. More preferred. In addition, as other diamine compounds, 4,4′-diaminodiphenylmethane, 3,3′-dimethyl-4,4′-diaminobiphenyl, and 4,4 are obtained for sufficiently obtaining the effect of the liquid crystal aligning agent of the present invention. It is preferable to use at least one diamine compound selected from '-diaminodiphenyl ether and 4,4'-diaminobenzophenone.

Moreover, as a diamine compound which can be used for the polyimide polymer which has a structure represented by R < ² > of said Formula (I-2), the same thing as the above can be used. Among these, from the viewpoint of storage stability and viscosity, p-phenylenediamines that give a divalent organic residue represented by the above formula (II) as R ^{2 in} the formula (I-2), as well as the following formula

ここでＲは水素原子または炭素数１〜４の単価水素基を示し、複数存在するＲは同一でも異なっていてもよく、ｎは１〜４の整数である、
で表わされる２価の有機残基を与える４,４’−ジアミノジフェニルメタン類、同様に下記式

Here, R represents a hydrogen atom or a monovalent hydrogen group having 1 to 4 carbon atoms, a plurality of R may be the same or different, and n is an integer of 1 to 4.
4,4′-diaminodiphenylmethanes which give a divalent organic residue represented by the formula:

ここで、Ｒおよびｎの定義は上記式に同じである、
で表わされる２価の有機残基を与える３,３’−ジメチル−４,４’−ジアミノビフェニル類、同様に下記式

Here, the definitions of R and n are the same as in the above formula.
3,3′-dimethyl-4,4′-diaminobiphenyls which give a divalent organic residue represented by the formula:

ここで、Ｒおよびｎの定義は上記式に同じである、
で表わされる２価の有機残基を与える４,４’−ジアミノジフェニルエーテル類、同様に下記式

Here, the definitions of R and n are the same as in the above formula.
4,4′-diaminodiphenyl ethers which give a divalent organic residue represented by the formula:

ここで、Ｒおよびｎの定義は前記式に同じである、
で表わされる２価の有機残基を与える４,４’−ジアミノベンゾフェノン類、および同様に下記式

Here, the definitions of R and n are the same as in the above formula.
4,4′-diaminobenzophenones which give a divalent organic residue represented by the formula:

ここで、Ｒの定義は上記式に同じである、
で表わされる２価の有機残基を与える２,２−ビス［４−（４−アミノフェノキシ）フェニル］プロパン類から選ばれる少なくとも一種のジアミン化合物を使用することが好ましい。

Here, the definition of R is the same as the above formula.
It is preferable to use at least one diamine compound selected from 2,2-bis [4- (4-aminophenoxy) phenyl] propanes which give a divalent organic residue represented by:

[Synthesis of polyamic acid]
The ratio of tetracarboxylic dianhydride and diamine used in the polyamic acid synthesis reaction is 0.2 to 2.2 based on 1 equivalent of amino group of diamine and tetracarboxylic dianhydride acid anhydride group. A ratio of 0 equivalent is preferable, and a ratio of 0.8 to 1.2 equivalent is more preferable. The polyamic acid synthesis reaction is preferably performed in an organic solvent under a temperature condition of −20 ° C. to 150 ° C., more preferably 0 to 100 ° C.

  Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized polyamic acid. For example, 1-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide And aprotic polar solvents such as γ-butyrolactone, tetramethylurea and hexamethylphosphortriamide; and phenolic solvents such as m-cresol, xylenol, phenol and halogenated phenol. The amount of organic solvent used (α) is usually such that the total amount (β) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight based on the total amount (α + β) of the reaction solution. It is preferable that the amount is small.

  In addition, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc., which are poor solvents for polyamic acid, are used in combination with the organic solvent as long as the resulting polyamic acid does not precipitate. be able to. Specific examples of such poor solvents include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol. , Ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, malon Acid diethyl, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i- Propyl ether, ethylene glycol-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane Examples include 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, and the like.

  As described above, a reaction solution obtained by dissolving polyamic acid is obtained. The reaction solution is poured into a large amount of poor solvent to obtain a precipitate, and the precipitate is dried under reduced pressure to obtain a polyamic acid. The polyamic acid can be purified by dissolving the polyamic acid again in an organic solvent and then precipitating with a poor solvent once or several times.

[Synthesis of polyimide]
The polyimide constituting the liquid crystal aligning agent of the present invention can be synthesized by dehydrating and ring-closing the polyamic acid synthesized as described above. The polyimide used in the present invention may be partially dehydrated and ring-closed with an imidization rate of less than 100%. The “imidation ratio” here is a value representing the ratio of the repeating unit having an imide ring or an isoimide ring as a percentage in all repeating units. The polyamic acid is dehydrated and closed by (i) a method of heating the polyamic acid, or (ii) dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to this solution, and heating as necessary. By the method.

  The reaction temperature in the method of heating the polyamic acid (i) is preferably 50 to 200 ° C, more preferably 60 to 170 ° C. When the reaction temperature is less than 50 ° C., the dehydration ring-closing reaction does not proceed sufficiently, and when the reaction temperature exceeds 200 ° C., the molecular weight of the resulting polyimide may decrease.

  On the other hand, in the method (ii) of adding a dehydrating agent and a dehydrating ring-closing catalyst to the polyamic acid solution, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride is used as the dehydrating agent. Can do. Although the usage-amount of a dehydrating agent is based on the desired imidation rate, it is preferable to set it as 0.01-20 mol with respect to 1 mol of repeating units of a polyamic acid. Moreover, as a dehydration ring closure catalyst, tertiary amines, such as a pyridine, a collidine, a lutidine, a triethylamine, can be used, for example. However, it is not limited to these. The amount of the dehydration ring-closing catalyst used is preferably 0.01 to 10 mol with respect to 1 mol of the dehydrating agent used. The imidation rate can be increased as the amount of the above dehydrating agent and dehydrating ring-closing agent increases. The imidation ratio is preferably 50 to 100%, more preferably 70 to 100%, from the viewpoint of developing the characteristics of the liquid crystal display element. In addition, as an organic solvent used for dehydration ring closure reaction, the same organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. And reaction temperature of dehydration ring closure reaction becomes like this. Preferably it is 0-180 degreeC, More preferably, it is 10-150 degreeC. Moreover, a polyimide can be refine | purified by performing operation similar to the purification method of a polyamic acid with respect to the reaction solution obtained in this way.

[End-modified polymer]
The polyamic acid / polyimide of the present invention may be a terminal-modified type having a controlled molecular weight. By using this terminal-modified polymer, the coating characteristics of the liquid crystal aligning agent can be improved without impairing the effects of the present invention. Such a terminal-modified polymer can be synthesized, for example, by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound, or the like to the reaction system when synthesizing a polyamic acid. Here, as the acid monoanhydride, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride , N-hexadecyl succinic anhydride and the like. Examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, and n-undecylamine. N-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, etc. Can do. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

[Logarithmic viscosity of polymer]
The polyamic acid and / or polyimide obtained as described above preferably have a logarithmic viscosity (η _ln ) of 0.05 to 10 dl / g, more preferably 0.05 to 5 dl / g.

The value of the logarithmic viscosity (η _ln ) in the present invention is determined by measuring the viscosity at 30 ° C. for a solution having a concentration of 0.5 g / 100 ml using N-methyl-2-pyrrolidone as a solvent. ).

[Liquid crystal aligning agent for horizontal electric field]
In order to obtain the liquid crystal aligning agent of the present invention, the polyamic acid and the polyimide are dissolved in a solvent, and then the polyamic acid is mixed at 50 to 89% by weight with respect to the total weight of the polyamic acid and the polyimide. It is obtained by mixing both. When the mixing ratio is less than 50% by weight, the rubbing resistance and the like are lowered, and when it exceeds 89% by weight, the effects of the present invention such as a decrease in the voltage holding ratio and an increase in the amount of accumulated charge cannot be obtained sufficiently. This is not preferable because there are some cases. Examples of the method of mixing polyamic acid and polyimide include a method of dissolving after mixing in a powder state and a method of adding powdered polyimide to a polyamic acid solution, but the mixing method is not particularly limited. . Moreover, the temperature at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 0 to 200 degreeC, More preferably, it is 20 to 60 degreeC.

  Examples of the organic solvent constituting the liquid crystal aligning agent of the present invention include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4-hydroxy- 4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether , Ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl Examples include ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, and diethylene glycol monoethyl ether acetate.

  The solid content concentration in the liquid crystal aligning agent of the present invention is selected in consideration of viscosity, volatility, etc., but is preferably in the range of 1 to 10% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface to form a resin film that becomes a liquid crystal aligning film. When the solid content concentration is less than 1% by weight, the film thickness of the resin film is It is difficult to obtain a good liquid crystal alignment film because it is too small, and when the solid content concentration exceeds 10% by weight, the resin film thickness becomes excessive and a good liquid crystal alignment film can be obtained. In addition, the viscosity of the liquid crystal aligning agent increases and the coating properties are inferior.

  The liquid crystal aligning agent of this invention may contain the functional silane containing compound and the epoxy compound from a viewpoint which improves the adhesiveness with respect to the substrate surface within the range which does not impair the target physical property. Examples of such functional silane-containing compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl). -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-amino Propyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl- , 4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N -Bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, etc. can be mentioned. Examples of such epoxy compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexane. Diol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ′, N′— Tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4 ′ Diaminodiphenylmethane, 3- (N-Ariru N Gurishijiru) aminopropyltrimethoxysilane, 3- (N, N-diglycidyl) and aminopropyl trimethoxy silane can be cited.

[Liquid crystal display element]
The horizontal electric field mode liquid crystal display element of the present invention can be manufactured, for example, by the following method.
(1) Liquid crystal alignment of the present invention on a substrate in which a transparent electrode such as ITO (Indium Tin Oxide) or a metal electrode such as chrome is patterned in a comb-tooth shape and on one surface of the counter substrate where no electrode is provided The agent is applied by a method such as a roll coater method, a spinner method, or a printing method, and then the applied surface is heated to form a resin film. Here, as the substrate, for example, a glass such as float glass or soda glass; a transparent substrate made of a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, or polycarbonate can be used. For patterning these electrodes, photo-etching, sputtering, chemical vapor deposition, or the like is used. In applying the liquid crystal aligning agent, for example, a functional silane-containing compound or a functional titanium-containing compound can be applied in advance in order to further improve the adhesion between the substrate surface and the resin film. The heating temperature after application of the liquid crystal aligning agent is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The liquid crystal aligning agent of the present invention forms a resin film that becomes an alignment film by removing the organic solvent after coating. However, when imidization has not progressed completely, dehydration ring closure proceeds by further heating. It is also possible to obtain a more imidized resin film. The film thickness of the formed resin film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.

(2) A rubbing process is performed in which the formed resin film surface is rubbed in a certain direction with a roll wound with a cloth made of fibers such as nylon, rayon, and cotton. Thereby, the alignment ability of the liquid crystal molecules is imparted to the resin film to form a liquid crystal alignment film.

  Further, by partially irradiating the liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention with ultraviolet rays as disclosed in, for example, JP-A-6-222366 and JP-A-6-281937. A resist film is partially formed on the surface of the liquid crystal alignment film which has been subjected to a treatment for changing the pretilt angle or a rubbing treatment as disclosed in JP-A-5-107544, which is different from the previous rubbing treatment. The visibility characteristics of the liquid crystal display element can be improved by removing the resist film after performing the rubbing treatment in the direction and changing the liquid crystal alignment ability of the liquid crystal alignment film.

(3) A substrate on which electrodes are formed as described above and a substrate on which no electrodes are formed are prepared one by one, and the two substrates are mounted so that the rubbing directions in the respective liquid crystal alignment films are antiparallel. , Facing each other through a gap (cell gap), the peripheral portions of two substrates are bonded together using a sealant, and liquid crystal is injected and filled into the cell gap defined by the substrate surface and the sealant, Is sealed to form a liquid crystal cell. Then, a polarizing plate is provided on the outer surface of the liquid crystal cell, that is, the other surface side of each substrate constituting the liquid crystal cell, so that the polarization direction thereof coincides with the rubbing direction of the liquid crystal alignment film formed on one surface of the substrate. By sticking together, a horizontal electric field type liquid crystal display element is obtained.

Here, as the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.
Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferable. For example, Schiff base liquid crystals, azoxy liquid crystals, biphenyl liquid crystals, phenylcyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals. A liquid crystal, a biphenylcyclohexane liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, a bicyclooctane liquid crystal, a cubane liquid crystal, or the like can be used.
In addition, as a polarizing plate bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film in which a polarizing film called an H film that absorbs iodine is stretched and oriented while sandwiching polyvinyl alcohol with a cellulose acetate protective film. The polarizing plate which consists of itself can be mentioned.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Examples 1 to 8 and 12 to 16 are reference examples.

  Various measurements in Examples and Comparative Examples were performed by the following methods.

(1) Measurement of voltage holding ratio After applying a voltage of 5 V to a liquid crystal display element at 60 ° C. with an application time of 60 microseconds and a span of 167 microseconds, the voltage holding ratio after 167 milliseconds from the release of application was measured. .

(2) Measurement of charge accumulation amount The voltage accumulated in the liquid crystal display element when the voltage of 5 V is applied to the liquid crystal display element at 60 ° C. for 60 minutes and then shorted for 1 second and then kept open for 10 minutes. It was measured by the dielectric absorption method.

(3) Evaluation of rubbing resistance A liquid crystal aligning agent was applied on an ITO substrate, dried and baked to form an 800-mm coating film, which was rubbed and the surface state of the coating film was observed with a microscope. . The rubbing was performed using a rubbing machine having a roll around which a nylon cloth was wound, with a roll rotation speed of 1000 rpm, a stage moving speed of 25 mm / sec, and a hair foot pushing length of 0.4 mm. The evaluation was performed based on the presence or absence of scraping or scraping by rubbing.

Synthesis Example 1 (Synthesis of polyimide polymer)
2,3,5-tricarboxycyclopentylacetic acid dianhydride 22.1 g (0.1 mol) as tetracarboxylic dianhydride and 19.8 g (0.1 mol) 4,4'-diaminodiphenylmethane as diamine compound Was dissolved in 168 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 4 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 29.3 g of polyamic acid having a logarithmic viscosity of 0.42 dl / g. The obtained polyamic acid was dissolved in 550 g of N-methyl-2-pyrrolidone, 39.5 g of pyridine and 30.6 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. And 21.5 g of polyimide (A-1) having a logarithmic viscosity of 0.64 dl / g and an imidization rate of 92% was obtained.

Synthesis Example 2 (Synthesis of polyimide polymer)
In Synthesis Example 1, a polyamic acid was obtained in the same manner as in Synthesis Example 1 except that 10.8 g (0.1 mol) of p-phenylenediamine was used as the diamine compound. The imidization reaction was performed to obtain 24.9 g of polyimide (A-2) having a logarithmic viscosity of 0.77 dl / g and an imidization ratio of 93%.

Synthesis Example 3 (Synthesis of polyimide polymer)
As tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride 22.1 g (0.1 mol) and as a diamine compound 19.8 g (0.1 mol) of 4,4′-diaminodiphenylmethane Was dissolved in 168 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 4 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 28.6 g of polyamic acid having a logarithmic viscosity of 0.42 dl / g. The obtained polyamic acid was dissolved in 550 g of N-methyl-2-pyrrolidone, 15.7 g of pyridine and 20.3 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. Was performed to obtain 23.5 g of polyimide (A-3) having a logarithmic viscosity of 0.51 dl / g and an imidization ratio of 80%.

Synthesis Example 4 (Synthesis of polyimide polymer)
In Synthesis Example 3, a polyamic acid was obtained in the same manner as in Synthesis Example 3 except that 10.8 g (0.1 mol) of p-phenylenediamine was used as the diamine compound. The imidization reaction was performed to obtain 21.8 g of polyimide (A-4) having a logarithmic viscosity of 0.43 dl / g and an imidization ratio of 83%.

Synthesis Example 5 (Synthesis of polyimide polymer)
In Synthesis Example 3, a polyamic acid was obtained in the same manner as in Synthesis Example 3, except that 21.0 g (0.1 mol) of 2,2′-dimethyl-4,4′-diaminobiphenyl was used as the diamine compound. Using this, an imidization reaction was performed in the same manner as in Synthesis Example 3 to obtain 21.4 g of polyimide (A-5) having a logarithmic viscosity of 0.43 dl / g and an imidization ratio of 83%.

Synthesis Example 6 (Synthesis of polyimide polymer)
In Synthesis Example 3, the same procedure as in Synthesis Example 3 was conducted, except that 5.4 g (0.05 mol) of p-phenylenediamine and 9.9 g (0.05 mol) of 4,4′-diaminodiphenylmethane were used as the diamine compound. Thus, a polyamic acid was obtained, and an imidization reaction was further carried out in the same manner as in Synthesis Example 3 to obtain 19.0 g of polyimide (A-6) having a logarithmic viscosity of 0.44 dl / g and an imidization ratio of 81%. .

Synthesis Example 7 (Synthesis of polyamic acid polymer)
As tetracarboxylic dianhydride, 47.3 g (0.24 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 27.7 g (0.25 mol) of p-phenylenediamine as a diamine compound. , Dissolved in 475 g of N-methyl-2-pyrrolidone and reacted at 40 ° C. for 4 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 56.2 g of polyamic acid (B-1) having a logarithmic viscosity of 1.06 dl / g.

Synthesis Example 8 (Synthesis of polyamic acid polymer)
As tetracarboxylic dianhydride, 26.9 g (0.12 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride and 23.7 g (0,2) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride .12 mol) was used in the same manner as in Synthesis Example 7 to obtain 52.6 g of polyamic acid (B-2) having a logarithmic viscosity of 1.13 dl / g.

Synthesis Example 9 (Synthesis of polyamic acid polymer)
A logarithmic viscosity of 0.8 was obtained in the same manner as in Synthesis Example 7 except that 20.6 g (0.19 mol) of p-phenylenediamine and 9.9 g (0.05 mol) of 4,4′-diaminodiphenylmethane were used as the diamine compound. 50.9 g of 98 dl / g polyamic acid (B-3) was obtained.

Synthesis Example 10 (Synthesis of polyamic acid polymer)
Polyamic acid (B-4) having a logarithmic viscosity of 1.22 dl / g in the same manner as in Synthesis Example 7 except that 50.1 g (0.23 mol) of pyromellitic dianhydride was used as the tetracarboxylic dianhydride. 51.4 g was obtained.

Synthesis Example 11 (Synthesis of polyamic acid polymer)
As tetracarboxylic dianhydride, 26.2 g (0.12 mol) of pyromellitic dianhydride and 23.5 g (0.12 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride were used. 52.5 g of polyamic acid (B-5) having a logarithmic viscosity of 1.04 dl / g was carried out in the same manner as in Synthesis Example 7 except that 47.5 g (0.24 mol) of 4,4′-diaminodiphenylmethane was used as the diamine compound. Got.

Example 1
N-methyl is used so that the polyimide (A-1) obtained in Synthesis Example 1 and the polyamic acid (B-1) obtained in Synthesis Example 7 are polyimide: polyamic acid = 15: 85 (weight ratio). N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane (molecular weight of about 400) is dissolved in the polymer 100 by dissolving in 2-pyrrolidone / butyl cellosolve mixed solution (weight ratio 85/15). On the other hand, 5 parts by weight was dissolved to obtain a solution having a solid content concentration of 4% by weight. This solution was filtered using a filter having a pore diameter of 1 μm to prepare a film forming composition of the present invention.

  Next, the film-forming composition is applied by a spinner on a glass substrate having a thickness of 1 mm having a chromium electrode provided in a comb shape on one side, and dried on a hot plate at 230 ° C. for 10 minutes. A resin film having a thickness of 800 angstroms was formed.

  The formed resin film surface was rubbed using a rubbing machine having a roll around which a nylon cloth was wound to obtain a liquid crystal alignment film. Here, the rubbing treatment conditions were a roll rotation speed of 1000 rpm, a stage moving speed of 25 mm / second, and a hair foot pushing length of 0.4 mm (this substrate is referred to as “substrate A”). When the rubbing resistance of the substrate was evaluated, no scraping or scraping due to rubbing was observed.

  Similarly, the film-forming composition was applied to one surface of a glass substrate having a thickness of 1 mm by a spinner and dried on a hot plate at 230 ° C. for 10 minutes to form a resin film having a thickness of 800 Å.

  The formed resin film surface was rubbed using a rubbing machine having a roll around which a nylon cloth was wound to obtain a liquid crystal alignment film. Here, the rubbing treatment conditions were a roll rotation speed of 1000 rpm, a stage moving speed of 25 mm / second, and a hair foot pushing length of 0.4 mm (this substrate is referred to as “substrate B”). Similarly, when rubbing resistance was evaluated, no scraping or scraping due to rubbing was observed.

Subsequently, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is applied to the outer edge of the substrate having the liquid crystal alignment film of the liquid crystal sandwich substrate subjected to rubbing treatment, and then the rubbing direction in each liquid crystal alignment film is antiparallel. The two substrates were arranged so as to face each other with a gap therebetween, and the outer edge portions were brought into contact with each other and pressed to cure the adhesive. Next, a nematic liquid crystal (MLC-2042, manufactured by Merck & Co., Inc.) is filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port is sealed with an acrylic photo-curing adhesive. A polarizing plate was laminated to prepare a liquid crystal display element.
When the voltage holding ratio of the obtained liquid crystal display element was evaluated, a relatively high value of 93.1% was obtained. Further, when the charge accumulation amount was measured, it showed a very small value of 0.4V. The results are summarized in Table 1.

Examples 2 to 4, 9, 12 and Comparative Example 1
Except for using the polymer / mixing ratio shown in Table 1, the coating film was formed and the liquid crystal display element was prepared in the same manner as in Example 1, and various evaluations were performed. The results are summarized in Table 1.

Examples 5-8, 10-11, 13-16, Comparative Examples 2-8
In the same manner as in Example 1 except that the weight ratio of the N-methyl-2-pyrrolidone / butyl cellosolve mixed solution was changed to 80/20 and the polymer / mixing ratio shown in Table 1 was used, A liquid crystal display element was prepared and subjected to various evaluations. The results are summarized in Table 1.

Claims (4)

A polyamic acid polymer containing a repeating unit represented by the following formula (I-1)

(W ¹ represents a tetravalent organic residue obtained by removing four carboxyl groups from tetracarboxylic acid, and R ¹ represents a divalent organic residue obtained by removing two amino groups from diamine.)
And a polyimide polymer containing an imide repeating unit represented by the following formula (I-2)

(W ² represents a tetravalent organic residue obtained by removing four carboxyl groups from tetracarboxylic acid, and R ² represents a divalent organic residue obtained by removing two amino groups from diamine.)
The polyamic acid is a divalent organic residue R ¹ represented by the following formula (II) based on the total number of repeating units represented by the formula (I-1).

(Here, R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or a monovalent organic group.)
W ¹ which is a tetravalent organic residue containing at least 50 mol% of the repeating unit represented by the formula (I-1) represented by the formula (III)

(Here, R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a monovalent organic group.)
At least 30 mol% of the repeating unit represented by the formula (I-1) represented by the formula:

(Here, R ¹¹ represents a hydrogen atom or a monovalent organic group.)
A repeating unit represented by the formula (I-1) which is at least one selected from the group consisting of tetravalent organic residues represented by each of the above and the polyamic acid polymer, the polyamic acid polymer and the polyimide A liquid crystal aligning agent for a horizontal electric field mode liquid crystal display element, comprising 40 to 89% by weight based on the total amount of polymers. The divalent organic residue of R ^{2 in} the above formula (I-2) is represented by the following formula:

(Wherein R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or a monovalent organic group, and R represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, A plurality of R may be the same or different, and n is an integer of 1 to 4.)
Of at least one selected from the group consisting of divalent organic residue represented by each of the liquid crystal aligning agent of claim 1. W ² which is a tetravalent organic residue in the above formula (I-2) is represented by the following formula (IV)

(Here, R ¹¹ represents a hydrogen atom or a monovalent organic group.)
A tetravalent organic residue represented by formula (V):

And the tetravalent organic residue represented by the formula (V) is at least 50 mol% based on the total of these tetravalent organic residues. The liquid crystal aligning agent in any one of 2 . Characterized by comprising comprises a liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 3, the horizontal electric field mode liquid crystal display device.