JP5434927B2 - Liquid crystal alignment treatment agent and liquid crystal display element using the same - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film using the same, and a liquid crystal display element.

  A liquid crystal display element has a structure in which liquid crystal molecules are sandwiched between liquid crystal alignment films formed on a substrate, and is a display element utilizing the fact that liquid crystal molecules aligned in a certain direction by a liquid crystal alignment film respond with voltage. is there. This liquid crystal alignment film is generally produced by performing a so-called “rubbing process” in which the surface of a polyimide film formed on a substrate with electrodes is rubbed against the surface with rayon or nylon cloth. . Since the rubbing treatment determines the alignment direction and the pretilt angle of the liquid crystal molecules, the rubbing treatment is a very important process. However, the rubbing treatment has a big problem of scratches on the film surface and peeling of the film. Scratches and peeling on the surface of the liquid crystal alignment film are important problems because they cause display defects when the liquid crystal display element is formed.

As a means for forming a polyimide film on a substrate with electrodes, a method of forming a coating film using a solution of a polyimide precursor such as polyamic acid and imidizing on the substrate, and a soluble polyimide that has been imidized in advance. And a method using a solution containing.
Among them, the method using a solution containing a soluble polyimide is capable of forming a polyimide film having good characteristics when used as a liquid crystal alignment film even when firing at a relatively low temperature. Further, the strength of the film is low, and problems associated with the rubbing treatment are likely to occur.

  In view of the above circumstances, the present applicant has already disclosed a specific diamine component according to Patent Document 1 in which the solubility of polyimide in an organic solvent is improved and the film surface is not easily scratched or peeled off by rubbing treatment. The liquid crystal aligning agent containing the soluble polyimide which imidized the polyamic acid obtained by using is proposed.

  Furthermore, with the increase in the size and brightness of the panel, a decrease in the pretilt angle is becoming a problem due to the heat generated from the backlight. As a method for expressing the pretilt angle, a diamine having an alkyl side chain (for example, see Patent Document 2), a diamine having a steroid skeleton in the side chain (for example, Patent Document 3), and a diamine having a ring structure in the side chain (for example, Patent Document) 4) has been proposed. In general, when a diamine having an alkyl side chain is used, the liquid crystal orientation is good, but the thermal stability of the pretilt angle is poor, and the pretilt angle decreases as the temperature increases. On the other hand, a polyamic acid or soluble polyimide using a diamine having a steroid skeleton or a ring structure in the side chain is excellent in thermal stability at a pretilt angle, but tends to decrease liquid crystal orientation and solubility in an organic solvent.

International Publication No. 2006/126555 Pamphlet Japanese Patent Laid-Open No. 05-043687 Japanese Patent Laid-Open No. 04-281427 Japanese Patent Laid-Open No. 02-223916

  In view of the above situation, an object of the present invention is to provide a liquid crystal alignment treatment agent for forming a liquid crystal alignment film that satisfies alignment during liquid crystal injection, resistance to rubbing treatment, and stabilization of a pretilt angle at high temperature. . That is, according to the present invention, scratches on the liquid crystal alignment film surface due to rubbing treatment and peeling of the liquid crystal alignment film hardly occur, the liquid crystal alignment property at the time of liquid crystal injection is good, and the pretilt angle is stable and difficult to decrease even at high temperatures. It aims at providing the liquid-crystal aligning agent for forming a film | membrane.

As a result of intensive studies to achieve the above object, the present inventors have completed the present invention. That is, the present invention has the following gist.
(1) A polyamic acid obtained by reacting a diamine component with a tetracarboxylic dianhydride component and a soluble polyimide obtained by imidizing the polyamic acid, containing at least one polymer, wherein the diamine component has the formula A liquid crystal aligning agent comprising a diamine represented by [1] and a diamine represented by formula [2].

（式中、nは０〜１９の整数である。）
（２）テトラカルボン酸二無水物成分とジアミン成分の含有比率が、モル比で１：０．８〜１：１．２である上記（１）に記載の液晶配向処理剤。
（３）ジアミン成分が、式［１］で表されるジアミンを２０モル％以上含有する上記（１）又は(２)に記載の液晶配向処理剤。
（４）ジアミン成分が、式［２］で表されるジアミンを５〜６０モル％含有する上記（１）〜（３）のいずれかに記載の液晶配向処理剤。
（５）ジアミン成分中の式［２］で表されるジアミンが、式［１］で表されるジアミンの1モルに対して０．１モル〜１．２モル含有する上記（１）〜（４）のいずれかに記載の液晶配向処理剤。
（６）式［１］で表されるジアミン及び式［２］で表されるジアミンの、それぞれの有する２つのアミノ基の位置関係が、メタ位又はパラ位である上記（１）〜（５）のいずれかに記載の液晶配向処理剤。
（７）テトラカルボン酸二無水物成分が、脂環式構造又は脂肪族構造を有するテトラカルボン酸二無水物を含有する上記（１）〜（６）のいずれかに記載の液晶配向処理剤。
（８）テトラカルボン酸二無水物成分が、芳香族テトラカルボン酸二無水物を含有する上記（１）〜（７）のいずれかに記載の液晶配向処理剤。
（９）上記（１）〜（８）のいずれかに記載の液晶配向処理剤を電極付き基板上に塗布、焼成し、ラビング処理して得られる液晶配向膜。
（１０）上記（９）に記載の液晶配向膜を用いた液晶表示素子。

(In the formula, n is an integer of 0 to 19.)
(2) The liquid-crystal aligning agent as described in said (1) whose content ratio of a tetracarboxylic dianhydride component and a diamine component is 1: 0.8-1: 1.2 by molar ratio.
(3) The liquid-crystal aligning agent as described in said (1) or (2) in which a diamine component contains 20 mol% or more of diamine represented by Formula [1].
(4) The liquid-crystal aligning agent in any one of said (1)-(3) in which a diamine component contains 5-60 mol% of diamine represented by Formula [2].
(5) The above (1) to (1), wherein the diamine represented by the formula [2] in the diamine component contains 0.1 mol to 1.2 mol with respect to 1 mol of the diamine represented by the formula [1]. 4) The liquid-crystal aligning agent in any one of.
(6) The above (1) to (5), wherein the positional relationship between the two amino groups of the diamine represented by the formula [1] and the diamine represented by the formula [2] is the meta position or the para position. ) The liquid crystal aligning agent according to any one of
(7) The liquid-crystal aligning agent in any one of said (1)-(6) in which the tetracarboxylic dianhydride component contains the tetracarboxylic dianhydride which has an alicyclic structure or an aliphatic structure.
(8) The liquid-crystal aligning agent in any one of said (1)-(7) in which a tetracarboxylic dianhydride component contains aromatic tetracarboxylic dianhydride.
(9) A liquid crystal alignment film obtained by applying the liquid crystal alignment treatment agent according to any one of (1) to (8) above onto a substrate with an electrode, baking, and rubbing.
(10) A liquid crystal display device using the liquid crystal alignment film according to (9).

  By using the liquid crystal aligning agent of the present invention, it is possible to form a liquid crystal alignment film with good liquid crystal alignment during liquid crystal injection, and scratching the surface of the liquid crystal alignment film during rubbing or Since peeling is suppressed and the pretilt angle is difficult to decrease at high temperatures, a liquid crystal display element having few display defects and stable characteristics at high temperatures can be obtained.

  The liquid-crystal aligning agent of this invention contains the polyamic acid obtained by making a diamine component and a tetracarboxylic dianhydride component react, and / or the soluble polyimide which imidated this polyamic acid, The said diamine component is And a diamine represented by the following formula [1] and formula [2]. In the present invention, the soluble polyimide refers to a polyimide that is soluble in an organic solvent used in the liquid crystal aligning agent of the present invention.

ここでｎは０〜１９の整数である。
式［１］で表されるジアミンにおいて、ベンゼン環上の各置換基の位置は特に限定されないが、２つのアミノ基の位置関係はメタ又はパラが好ましい。以下にこのジアミンの好ましい具体例を挙げるが、これに限定されるものではない。

Here, n is an integer of 0-19.
In the diamine represented by the formula [1], the position of each substituent on the benzene ring is not particularly limited, but the positional relationship between the two amino groups is preferably meta or para. Although the preferable specific example of this diamine is given to the following, it is not limited to this.

  In the present invention, the diamine component used as a raw material for the polyamic acid or soluble polyimide may be only the diamine represented by the formula [1] and the formula [2], or one or more selected from other diamines. And may be combined. By including the diamine represented by the formula [1] as a diamine component for obtaining a polyamic acid or a soluble polyimide, problems such as scratches on the film surface and film peeling when the coating film is rubbed are improved. At the same time, the solubility of polyimide in an organic solvent increases.

In the diamine component, the diamine represented by the formula [1] increases the effect of suppressing scratches on the surface of the alignment film during the rubbing treatment and peeling of the film as the content ratio increases. The solubility of the soluble polyimide in the organic solvent is also increased.
If the content of the diamine represented by the formula [1] is 5 mol% or more of the total diamine component, the effect of suppressing scratches on the alignment film surface and the film peeling during the rubbing treatment can be obtained. % Or more is preferable because sufficient resistance can be obtained even when combined with a diamine having low resistance to rubbing. Moreover, it is preferable that content of this diamine is 95 mol% or less.
The diamine represented by the formula [2] is an essential component for developing good liquid crystal orientation and a stable pretilt angle at high temperatures. Content of the diamine represented by Formula [2] in a diamine component is 0.1-1.2 mol with respect to 1 mol of diamine represented by Formula [1], Preferably it is 0.3-1. 1 mol, more preferably 0.5 to 1.1 mol. When the content of the diamine represented by the formula [2] is small, a desired pretilt angle may not be exhibited. Conversely, when the content is large, rubbing scraping becomes worse.
Although content of the diamine represented by Formula [2] in a diamine component can be adjusted with the magnitude | size of the target pretilt angle, 1-90 mol% is preferable, More preferably, it is 5-60 mol%.
In the diamine represented by the formula [2], the position of each substituent on the benzene ring is not particularly limited, but the positional relationship between the two amino groups is preferably meta or para. Although the preferable specific example of this diamine is given to the following, it is not limited to this.

ここでｎは０〜１９の整数である。ｎは小さい場合、プレチルト角が発現せず、大きい場合、可溶性ポリイミドの溶解性が低下する。よって好ましいｎの範囲は３〜１５であり、より好ましくは５〜１０である。

Here, n is an integer of 0-19. When n is small, the pretilt angle does not appear. When n is large, the solubility of the soluble polyimide decreases. Therefore, the range of preferable n is 3-15, More preferably, it is 5-10.

  In the above diamine component, the formulas [1] and [2] may be only these, but other diamines may be used in combination, and the other diamines in that case are not particularly limited, but specific examples thereof If indicated, the following amines may be mentioned.

  Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4′-diaminodicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexylamine, isophorone Examples include diamines.

  Examples of aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1,4-diamino. 2-methoxybenzene, 2,5-diamino-p-xylene, 1,3-diamino-4-chlorobenzene, 3,5-diaminobenzoic acid, 1,4-diamino-2,5-dichlorobenzene, 4,4 '-Diamino-1,2-diphenylethane, 4,4'-diamino-2,2'-dimethylbibenzyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane 4,4'-diamino-3,3'-dimethyldiphenylmethane, 2,2'-diaminostilbene, 4,4'-diamy Stilbene, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, 4,4′- Diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,5-bis (4- Aminophenoxy) benzoic acid, 4,4′-bis (4-aminophenoxy) bibenzyl, 2,2-bis [(4-aminophenoxy) methyl] propane, 2,2-bis [4- (4-aminophenoxy) Phenyl] hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- 3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 1,1-bis (4-aminophenyl) cyclohexane, α, α′-bis (4-aminophenyl) -1 , 4-diisopropylbenzene, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4, , 4'-diaminodiphenylamine, 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrene, 1,6-diaminopyrene, , 8-diaminopyrene, 2,7-diaminofluorene, 1,3-bis (4-aminophenyl) teto Methyldisiloxane, benzidine, 2,2'-dimethylbenzidine, 1,2-bis (4-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,4-bis (4-aminophenyl) ) Butane, 1,5-bis (4-aminophenyl) pentane, 1,6-bis (4-aminophenyl) hexane, 1,7-bis (4-aminophenyl) heptane, 1,8-bis (4- Aminophenyl) octane, 1,9-bis (4-aminophenyl) nonane, 1,10-bis (4-aminophenyl) decane, 1,3-bis (4-aminophenoxy) propane, 1,4-bis ( 4-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,7-bis (4-aminopheno) C) Heptane, 1,8-bis (4-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,10-bis (4-aminophenoxy) decane, di (4-aminophenyl) Propane-1,3-dioate, di (4-aminophenyl) butane-1,4-dioate, di (4-aminophenyl) pentane-1,5-dioate, di (4-aminophenyl) hexane-1,6 -Dioate, di (4-aminophenyl) heptane-1,7-dioate, di (4-aminophenyl) octane-1,8-dioate, di (4-aminophenyl) nonane-1,9-dioate, di ( 4-aminophenyl) decane-1,10-dioate, 1,3-bis [4- (4-aminophenoxy) phenoxy] propane, 1,4-bis [4- (4- Aminophenoxy) phenoxy] butane, 1,5-bis [4- (4-aminophenoxy) phenoxy] pentane, 1,6-bis [4- (4-aminophenoxy) phenoxy] hexane, 1,7-bis [4 -(4-aminophenoxy) phenoxy] heptane, 1,8-bis [4- (4-aminophenoxy) phenoxy] octane, 1,9-bis [4- (4-aminophenoxy) phenoxy] nonane, 1,10 -Bis [4- (4-aminophenoxy) phenoxy] decane and the like.

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

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

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

  Examples of diamines having a long chain alkyl group, a perfluoroalkyl group, an aromatic cyclic group, an aliphatic cyclic group, or a combination of these, a steroid skeleton group, and the like include the following. In the structure exemplified below, j represents an integer of 5 to 20, and k represents an integer of 1 to 20.

  In the present invention, the tetracarboxylic dianhydride component used as a raw material for polyamic acid or soluble polyimide may be one type of tetracarboxylic dianhydride, or a mixture of two or more types of tetracarboxylic dianhydride. May be used.

  These tetracarboxylic dianhydrides are particularly effective in improving the problems of the liquid crystal alignment properties, such as scratches and peeling of the surface of the liquid crystal alignment film that occur during rubbing treatment, and reduction of the pretilt angle at high temperatures. It is not limited.

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

  Furthermore, when an aromatic tetracarboxylic dianhydride is used in addition to the tetracyclic dianhydride having the alicyclic structure or aliphatic structure, the liquid crystal alignment is improved and the accumulated charge of the liquid crystal cell is reduced. Since it can reduce, it is preferable. As aromatic tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic acid Dianhydride, 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,3,3 ′, 4-benzophenonetetra Carboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride Products, 2,3,6,7-naphthalenetetracarboxylic dianhydride and the like.

  Considering the balance of the properties of polyamic acid or soluble polyimide such as liquid crystal orientation, voltage holding ratio, and accumulated charge, tetracarboxylic dianhydride having an alicyclic structure or aliphatic structure, and aromatic It is preferable to use together a group tetracarboxylic dianhydride. In that case, the former / latter molar ratio is preferably 90/10 to 50/50, more preferably 80/20 to 60/40.

  The polyamic acid or soluble polyimide used in the liquid crystal aligning agent of the present invention is a polyamic acid obtained by reacting the above-described diamine component and tetracarboxylic dianhydride component, or a polyimide obtained by imidizing this. Here, the reaction for obtaining a polyamic acid is possible by mixing a tetracarboxylic dianhydride component and a diamine component in an organic solvent.

  As a method of mixing a tetracarboxylic dianhydride component and a diamine component in an organic solvent, a solution in which the diamine component is dispersed or dissolved in an organic solvent is stirred, and the tetracarboxylic dianhydride component is left as it is or organically. A method of adding by dispersing or dissolving in a solvent, a method of adding a diamine component to a solution in which a tetracarboxylic dianhydride component is dispersed or dissolved in an organic solvent, and a tetracarboxylic dianhydride component and a diamine component. The method of adding alternately etc. are mentioned. Further, when the tetracarboxylic dianhydride component or the diamine component is composed of a plurality of types of compounds, they may be subjected to a polycondensation reaction in a state in which these plural types of compounds are mixed in advance, or may be sequentially subjected to a polycondensation reaction individually. Good.

  The temperature for polycondensation reaction of the tetracarboxylic dianhydride component and the diamine component in an organic solvent is usually 0 to 150 ° C, preferably 5 to 100 ° C, more preferably 10 to 80 ° C. The higher the temperature, the faster the polycondensation reaction is completed. However, if the temperature is too high, a high molecular weight polymer may not be obtained.

  The polycondensation reaction can be carried out at an arbitrary concentration. However, if the total mass concentration of the tetracarboxylic dianhydride component and the diamine component is too low, it becomes difficult to obtain a high molecular weight polymer. If the concentration of the total mass of the acid dianhydride component and the diamine component is too high, the viscosity of the reaction solution becomes too high and uniform stirring becomes difficult, so 1-50 mass%, more preferably 5-30. % By mass. The initial stage of the polycondensation reaction may be performed at a high concentration, and then an organic solvent may be added.

The organic solvent used in the above reaction is not particularly limited as long as the generated polyamic acid dissolves. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, N-methyl. Examples include caprolactam, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, and γ-butyrolactone. These may be used alone or in combination. Furthermore, even if the solvent does not dissolve the polyamic acid, it may be used by mixing with the above solvent as long as the produced polyamic acid does not precipitate.
Moreover, since water in the organic solvent inhibits the polycondensation reaction and further causes hydrolysis of the produced polyamic acid, it is preferable to use a dehydrated and dried organic solvent as much as possible.

  The ratio of the tetracarboxylic dianhydride component to the diamine component used for the polycondensation reaction of the polyamic acid is preferably 1: 0.8 to 1: 1.2 in terms of molar ratio, and this molar ratio is 1: 1. The closer the molecular weight of the polyamic acid obtained, the greater. By controlling the molecular weight of this polyamic acid, the molecular weight of the soluble polyimide obtained after imidization can be adjusted.

  Although the molecular weight of the soluble polyimide contained in the liquid crystal aligning agent of the present invention is not particularly limited, from the viewpoint of the strength of the coating film and the ease of handling as the liquid crystal aligning agent, the weight average molecular weight is 2,000 to 200. Is preferably 5,000 to 50,000, more preferably 5,000 to 50,000.

  The imidation of the polyamic acid obtained as described above is preferably carried out in an organic solvent by stirring in the presence of a basic catalyst and an acid anhydride, preferably for 1 to 100 hours.

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, acetic anhydride is preferable because the obtained polyimide can be easily purified after imidization. As an organic solvent, the solvent used at the time of the polycondensation reaction of the polyamic acid mentioned above can be used.

  The imidation ratio of the soluble polyimide can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time. The amount of the basic catalyst at this time is preferably 0.2 to 10 times mol, more preferably 0.5 to 5 times mol of the amic acid group. Further, the amount of the acid anhydride is preferably 1 to 30 times mol, more preferably 1 to 10 times mol of the amic acid group. The reaction temperature is preferably -20 to 250 ° C, more preferably 0 to 180 ° C. The reaction time is preferably 1 to 100 hours, preferably 1 to 20 hours.

Although the imidation ratio of the soluble polyimide contained in the liquid crystal aligning agent of the present invention is not particularly limited, it is preferably 40% or more, and preferably 60% or more, more preferably to obtain a high voltage holding ratio. 80% or more.
In the present invention, the imidization ratio of polyimide was measured as follows. Put 20 mg of polyimide powder into an NMR (nuclear magnetic resonance absorption) sample tube, add 0.53 ml of deuterated dimethyl sulfoxide (DMSO-d ₆ , 0.05% TMS (tetramethylsilane) mixture), and dissolve completely I let you. This solution was measured for proton NMR at 500 MHz with an NMR measuring instrument (JNM-ECA500) manufactured by JEOL Datum.
The imidation rate of the soluble polyimide is determined based on the proton derived from the structure that does not change before and after imidation as the reference proton, and is derived from the peak integrated value of this proton and the NH group of the amic acid that appears in the vicinity of 9.5 to 10.0 ppm. Using the proton peak integrated value, the following formula was used.
Imidation ratio (%) = (1−α · x / y) × 100
In the above formula, x is the proton peak integrated value derived from the NH group of the amic acid, y is the peak integrated value of the reference proton, and α is one NH group proton of the amic acid in the case of polyamic acid (imidation rate is 0%). The number ratio of the reference protons.
Since the added catalyst or the like remains in the solution of the soluble polyimide thus obtained, the soluble polyimide is preferably recovered and washed before use in the liquid crystal aligning agent of the present invention.

The soluble polyimide can be recovered by putting the solution after imidization into a poor solvent that is being stirred, and precipitating the polyimide, followed by filtration. Examples of the poor solvent at this time include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene. The recovered soluble polyimide can be washed with this poor solvent.
The polyimide recovered and washed in this way can be powdered by drying at normal temperature or under reduced pressure at room temperature or by heating.

The liquid crystal aligning agent of this invention is a polyamic acid and / or soluble polyimide (polyamic acid of this invention) obtained using the diamine component containing the diamine represented by Formula [1], and the diamine represented by Formula [2]. And / or soluble polyimide)), but other polyamic acid and / or soluble polyimide can also be contained in an appropriate ratio. In that case, from the viewpoint of appropriate tilt angle and orientation, the content of the polyamic acid and / or soluble polyimide of the present invention is 10 to 90% by mass with respect to all the polyamic acid and / or soluble polyimide. Is preferable, and it is more preferable that it is 10-40 mass%.
Although the liquid-crystal aligning agent of this invention contains at least 1 sort (s) of a polymer among the said polyamic acid and soluble polyimide, it is also possible to contain only a polyamic acid alone, and contains soluble polyimide alone. Is also possible. In order to obtain better printability and good afterimage characteristics, a liquid crystal aligning agent containing a polyamic acid and a soluble polyimide in an appropriate ratio can be obtained. In this invention, it is preferable that content of the soluble polyimide contained in a liquid-crystal aligning agent is 10-50 mass% with respect to the total content of a soluble polyimide and polyamic acid, and is 10-30 mass%. More preferably.

The preparation method of the liquid-crystal aligning agent of this invention is not specifically limited. For example, the polyamic acid solution obtained as described above is diluted to a desired concentration. The soluble polyimide solution is a method of dissolving the soluble polyimide powder obtained as described above in an organic solvent to obtain a polyimide solution, and then diluting to a desired concentration. In this dilution step, adjustment of the solvent composition for controlling the coating property to the substrate, addition of an additive for improving the properties of the coating film, and the like can be performed.
Furthermore, you may mix with the solution of the soluble polyimide of the structure different from the above, the solution of a polyamic acid, and you may add another resin component.

  Examples of the organic solvent for diluting the polyamic acid or the organic solvent for re-dissolving the polyimide powder include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and N-ethyl-2- Examples include pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-vinylpyrrolidone, dimethyl sulfoxide, tetramethyl urea, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone.

  Solvents added to control the coating property to the substrate 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, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl ester, lactate iso Such as mill esters. These solvents include a solvent that cannot dissolve polyamic acid or soluble polyimide alone, but can be mixed with the liquid crystal aligning agent of the present invention as long as polyamic acid or polyimide does not precipitate. it can. In particular, it is known that the coating film uniformity is improved upon application to a substrate by appropriately mixing a solvent having a low surface tension, and it is also suitably used in the liquid crystal aligning agent of the present invention.

  Additives for improving the properties of the coating include 3-aminopropylmethyldiethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane And silane coupling agents such as By adding these silane coupling agents, the adhesion of the coating film to the substrate can be further improved.

Although the solid content concentration of the liquid crystal aligning agent of this invention can be suitably changed with the setting of the thickness of the liquid crystal aligning film to form, it is preferable to set it as 0.5-10 mass%, and 1-8 mass%. More preferably. If it is less than 0.5% by mass, it is difficult to form a uniform and defect-free coating film, and if it exceeds 10% by mass, the storage stability of the solution may deteriorate. The solid content mentioned here refers to a component obtained by removing the solvent from the liquid crystal aligning agent.
The liquid crystal alignment treatment agent obtained as described above is preferably filtered before being applied to the substrate.

The liquid crystal aligning agent of this invention can be used as a liquid crystal aligning film by apply | coating to a board | substrate, drying and baking and setting it as a coating film, and rubbing the coating-film surface.
In this case, the substrate to be used is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used, and an ITO electrode for driving a liquid crystal is formed. It is preferable to use a new substrate from the viewpoint of simplification of the process. In the reflective liquid crystal display element, an opaque substrate such as a silicon wafer can be used as long as only one substrate is used. In this case, a material that reflects light such as aluminum can be used as the electrode.

  Examples of the method for applying the liquid crystal aligning agent include spin coating, printing, and ink-jet methods. From the viewpoint of productivity, the flexographic printing method is widely used industrially, and the liquid crystal aligning treatment of the present invention. It is also preferably used in agents.

  The drying process after applying the liquid crystal alignment treatment agent is not necessarily required, but if the time from application to baking is not constant for each substrate, or if baking is not performed immediately after application, the drying process is performed. Inclusion is preferred. This drying is not particularly limited as long as the solvent is evaporated to such an extent that the shape of the coating film is not deformed by transporting the substrate or the like. If a specific example is given, the method of drying on a hotplate of 50-150 degreeC, Preferably 80-120 degreeC for 0.5 to 30 minutes, Preferably it is 1 to 5 minutes is taken.

  The substrate coated with the liquid crystal aligning agent can be baked at an arbitrary temperature of 100 to 350 ° C., preferably 150 to 300 ° C., more preferably 180 to 250 ° C. When an amic acid group is present in the liquid crystal aligning agent, the conversion rate from the amic acid to the imide varies depending on the firing temperature, but the liquid crystal aligning agent of the present invention does not necessarily need to be 100% imidized. . However, baking is preferably performed at a temperature higher by 10 ° C. or more than the heat treatment temperature required for the liquid crystal cell manufacturing process, such as sealing agent curing.

  If the thickness of the coating film after baking is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may be lowered, so it is preferably 10 to 200 nm, more preferably 50-100 nm.

  An existing rubbing apparatus can be used for rubbing the coating surface formed on the substrate as described above. Examples of the material of the rubbing cloth at this time include cotton, rayon, and nylon.

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 method described above, and then preparing a liquid crystal cell by a known method.
As an example of liquid crystal cell production, a pair of substrates on which a liquid crystal alignment film is formed is preferably an arbitrary rubbing direction of 0 to 270 ° with a spacer of 1 to 30 μm, more preferably 2 to 10 μm sandwiched between them. A method is generally used in which the angle is set to be fixed, the periphery is fixed with a sealant, and liquid crystal is injected and sealed. 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.

  The liquid crystal display device thus obtained has good liquid crystal alignment properties, and display defects due to scratches and peeling of the liquid crystal alignment film that occur during rubbing treatment, and alignment defects due to a decrease in pretilt angle at high temperatures are reduced. Since the liquid crystal display device can be made highly reliable, it can be suitably used for display elements of various systems such as a TN liquid crystal display element, an STN liquid crystal display element, a TFT liquid crystal display element, and an OCB liquid crystal display element.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited to these.
The abbreviations of the compounds used in Examples and Comparative Examples are as follows.
<Tetracarboxylic dianhydride>
CA1: 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride CA2: 1,2,3,4-cyclobutanetetracarboxylic Acid dianhydride CA3: [3,3,0] bicyclooctane-2,3,5,6-tetracarboxylic dianhydride CA4: pyromellitic dianhydride

<Diamine>
DA1: 2,4-diamino-N, N-diallylaniline DA2: 1,3-diamino-4-octadecyloxybenzene DA3: 4- (trans-4-pentylcyclohexyl) benzamide-2 ′, 4′-phenylene Diamine DA4: p-phenylenediamine DA5: 4- {4- (4-heptylcyclohexyl) phenoxy} -1,3-diaminobenzene DA6: 4-aminobenzylamine DA7: 3-aminobenzylamine DA8: 1,3-diamino -4-Dodecyloxybenzene DA9: Di (4-aminophenyl) methane DA10: 1,3-diamino-4-tetradecyloxybenzene

<Organic solvent>
NMP: N-methyl-2-pyrrolidone γBL: γ-butyrolactone BC: Butyl cellosolve

Below, it shows about the evaluation method performed in the present Example.
<Measurement of molecular weight>
The molecular weight of the polyamic acid and the polyimide was measured with a GPC (normal temperature gel permeation chromatography) apparatus, and the number average molecular weight and the weight average molecular weight were calculated as polyethylene glycol and polyethylene oxide equivalent values.
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 additive, lithium bromide-hydrate (LiBr · H ₂ O) is 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) is 30 mmol / L , Tetrahydrofuran (THF) at 10 ml / L)
Flow rate: 1.0 ml / min Standard sample for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation and polyethylene glycol (molecular weight: about 12,000, 4,000, 1,000) manufactured by Polymer Laboratories .

<Measurement of imidization ratio>
The imidation ratio of polyimide was measured as follows. Put 20 mg of polyimide powder into an NMR (nuclear magnetic resonance absorption) sample tube, add 0.53 ml of deuterated dimethyl sulfoxide (DMSO-d ₆ , 0.05% TMS (tetramethylsilane) mixture), and dissolve completely I let you. This solution was measured for proton NMR at 500 MHz with an NMR measuring instrument (JNM-ECA500) manufactured by JEOL Datum. The imidation rate is determined based on protons derived from structures that do not change before and after imidation as reference protons, and the peak integrated value of these protons and proton peaks derived from NH groups of amic acid appearing near 9.5 to 10.0 ppm. Using the integrated value, it was determined by the following equation.
Imidation ratio (%) = (1−α · x / y) × 100
In the above formula, x is the proton peak integrated value derived from the NH group of the amic acid, y is the peak integrated value of the reference proton, and α is one NH group proton of the amic acid in the case of polyamic acid (imidation rate is 0%). The number ratio of the reference protons.

<Production of liquid crystal cell>
A liquid crystal alignment treatment agent is spin-coated on a glass substrate with a transparent electrode, dried on a hot plate at a temperature of 70 ° C. for 70 seconds, and then baked on a hot plate at 210 ° C. for 10 minutes to form a coating film having a thickness of 100 nm. I let you. This coating film surface was rubbed with a rubbing apparatus having a roll diameter of 120 mm using a rayon cloth under the conditions of a roll rotation speed of 1000 rpm, a roll traveling speed of 50 mm / sec, and an indentation amount of 0.3 mm to obtain a substrate with a liquid crystal alignment film.

  Prepare two sheets of this substrate, spray a 6μm spacer on the surface of the liquid crystal alignment film, print a sealant on it, and the other substrate faces the liquid crystal alignment film and the rubbing direction is perpendicular. After the lamination, the sealing agent was cured to produce an empty cell. Liquid crystal MLC-2003 (Merck Japan Co., Ltd.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain a twisted nematic liquid crystal cell.

<Measurement of pretilt angle>
The pretilt angle was measured using the liquid crystal cell obtained in the same manner as in the above <Production of liquid crystal cell>. For the measurement, TBA107 manufactured by autotronic was used. The measurement was performed before heating (23 ° C.) and under the condition that the liquid crystal cell was held at 60 ° C., and the amount of change in the pretilt angle before and after heating was evaluated.

<Evaluation of rubbing resistance>
In the above <Preparation of liquid crystal cell>, rubbing was performed under the condition that the indentation of the rubbing roller was changed to 0.5 mm, thereby preparing a substrate with a liquid crystal alignment film. The surface of the liquid crystal alignment film was observed with a laser microscope, and the following evaluation was performed visually.
○: Scraping and rubbing scratches hardly occur.
Δ: Waste or rubbing scratches.
X: The film peels off. Rubbing scratches are observed as streaks.

<Evaluation of liquid crystal alignment>
A liquid crystal cell (anti-parallel) was prepared under the same conditions as in the above <Preparation of liquid crystal cell> except that the rubbing roller push-in was changed to 0.2 mm. At that time, at the time of liquid crystal injection, the presence or absence of flow alignment of liquid crystal was observed from the injection port of the liquid crystal cell, and the following evaluation was performed.
○: Flow orientation is not observed.
X: Many streaky flow orientations are observed.

[Example 1]
As a tetracarboxylic dianhydride component, 12.49 g (42 mmol) of CA1 was used, 2.73 g (25 mmol) of DA4 and 3.43 g (8.4 mmol) of DA3 were used as a diamine component, and 1.71 g of DA1 was further used. (8.4 mmol) was used to react in 81.37 g of NMP at room temperature for 24 hours to obtain a polyamic acid solution. To 95.8 g of this polyamic acid solution, 242.7 g of NMP was added for dilution, and 42.81 g of acetic anhydride and 19.91 g of pyridine were added and reacted at a temperature of 40 ° C. for 3 hours to imidize. The reaction solution was cooled to about room temperature and then poured into 1404.1 ml of methanol to recover the precipitated solid. The solid was washed several times with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a white powder of soluble polyimide (SPI-1). The number average molecular weight of this polyimide was 12,207, and the weight average molecular weight was 40,065. Moreover, the imidation ratio was 85%. 10.8 g of γBL was added to 1.2 g of this polyimide powder and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After 12 g of this solution was cooled to 23 ° C., 2 g of γBL and 6 g of BC were added and stirred at a temperature of 50 ° C. for 20 hours. After stirring, the mixture was cooled to 23 ° C. to obtain a uniform liquid crystal aligning agent.
Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Example 2]
As tetracarboxylic dianhydride component, CA1 6.20 g (22 mmol), CA3 5.38 g (22 mmol), diamine component DA4 2.79 g (26 mmol), DA3 3.51 g (8.6 mmol) Then, 1.75 g (8.6 mmol) of DA1 was reacted in 78.49 g of NMP at 80 ° C. for 24 hours to obtain a polyamic acid solution. To 50 g of this polyamic acid solution, 114.3 g of NMP was added for dilution, and 6.34 g of acetic anhydride and 9.84 g of pyridine were added and reacted at a temperature of 100 ° C. for 3 hours to imidize. The reaction solution was cooled to about room temperature and then poured into 631.7 ml of methanol to recover the precipitated solid. Further, the solid was washed several times with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a white powder of polyimide (SPI-2). The number average molecular weight of this polyimide was 10,250, and the weight average molecular weight was 49,802. The imidation ratio was 82%. 10.8 g of γBL was added to 1.2 g of this polyimide powder and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After 12 g of this solution was cooled to 23 ° C., 2 g of γBL and 6 g of BC were added and stirred at a temperature of 50 ° C. for 20 hours. After stirring, the mixture was cooled to 23 ° C. to obtain a uniform liquid crystal aligning agent.
Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Example 3]
As a tetracarboxylic dianhydride component, 7.68 g (40 mmol) of CA2 and 2.60 g (24 mmol) of DA4, 3.42 g (8.4 mmol) of DA3 and 1.63 g (8. 4 mmol), and a reaction was performed in 85.96 g of NMP at room temperature for 24 hours to obtain a polyamic acid (PAA-1) solution. The number average molecular weight of this polyamic acid was 18,374, and the weight average molecular weight was 43,407. 10.5 g of NMP and 7.5 g of BC were added to 8 g of this solution and stirred at room temperature for 20 hours to obtain a uniform liquid crystal aligning agent.
Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Example 4]
As a tetracarboxylic dianhydride component, 8.18 g (42 mmol) of CA2 and 1.63 g (7.5 mmol) of CA4, as a diamine component, 1.22 g (10 mmol) of DA7 and 5.08 g (25 mmol) of DA1 Then, 6.11 g (15 mmol) of DA3 was used and reacted at room temperature in 88.96 g of NMP for 24 hours to obtain a polyamic acid solution. 228.5 g of NMP was added to 95.8 g of this polyamic acid solution for dilution, 15.1 g of acetic anhydride and 6.4 g of pyridine were added, and the mixture was reacted at 50 ° C. for 3 hours to imidize. The reaction solution was cooled to about room temperature and then poured into 1259.1 ml of methanol to recover the precipitated solid. The solid was washed several times with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a white powder of soluble polyimide (SPI-3). The number average molecular weight of this polyimide was 18,195, and the weight average molecular weight was 57,063. Moreover, the imidation ratio was 93%. 10.8 g of γBL was added to 1.2 g of this polyimide powder and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After 12 g of this solution was cooled to 23 ° C., 2 g of γBL and 6 g of BC were added and stirred at a temperature of 50 ° C. for 20 hours. After stirring, the mixture was cooled to 23 ° C. to obtain a uniform liquid crystal aligning agent.
Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Example 5]
As a tetracarboxylic dianhydride component, CA2 was 13.53 g (69 mmol), CA4 was 6.54 g (30 mmol), and as a diamine component, DA1 was 8.13 g (40 mmol), DA6 was 3.67 g (30 mmol), DA8. Was used for reaction for 24 hours at room temperature in 161.8 g of NMP to obtain a polyamic acid solution.
To 34.81 g of this polyamic acid solution, 62.65 g of NMP was added for dilution, and 5.15 g of acetic anhydride and 2.19 g of pyridine were added and reacted at a temperature of 50 ° C. for 3 hours to imidize.
The reaction solution was cooled to about room temperature and then poured into 366.8 ml of methanol to recover the precipitated solid. Further, this solid was washed several times with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a white powder of polyimide (SPI-4). The number average molecular weight of this polyimide was 12,016, and the weight average molecular weight was 35,126. Moreover, the imidation ratio was 90%.
10.8 g of γBL was added to 1.2 g of this polyimide powder and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After 12 g of this solution was cooled to 23 ° C., 2 g of γBL and 6 g of BC were added and stirred at a temperature of 50 ° C. for 20 hours. After stirring, the mixture was cooled to 23 ° C. to obtain a uniform liquid crystal aligning agent.
The SPI-4 and SPI-3 were mixed at a mass ratio of 7: 3 to obtain a liquid crystal aligning agent of the present invention. Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Example 6]
As a tetracarboxylic dianhydride component, CA2 was 6.86 g (35 mmol), CA4 was 3.27 g (15 mmol), diamine component was DA7 2.44 g (20 mmol), DA1 3.04 g (15 mmol), DA3 Was reacted for 24 hours at room temperature in 87.0 g of NMP to obtain a polyamic acid solution (PAA-2). The number average molecular weight of this polyamic acid was 15,539, and the weight average molecular weight was 47,210. 10.5 g of NMP and 7.5 g of BC were added to 8 g of this solution and stirred at room temperature for 20 hours to obtain a uniform liquid crystal aligning agent.
The PAA-2 and SPI-3 were mixed at a mass ratio of 8: 2 to obtain a liquid crystal aligning agent of the present invention. Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Example 7]
Using 9.80 g (50 mmol) of CA2 as a tetracarboxylic dianhydride component, 9.60 g (44 mmol) of CA4, and 19.8 g (100 mmol) of DA9 as a diamine component, the reaction was conducted at room temperature for 5 hours in 222 g of NMP. To obtain a polyamic acid solution (PAA-3). The number average molecular weight of this polyamic acid was 11,153, and the weight average molecular weight was 29,487. 10.5 g of NMP and 7.5 g of BC were added to 8 g of this solution and stirred at room temperature for 20 hours to obtain a uniform liquid crystal aligning agent.
The PAA-3 and PAA-1 were mixed at a mass ratio of 5: 5 to obtain the liquid crystal aligning agent of the present invention. Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Example 8]
SPI-3, SPI-4, and PAA-3 were mixed at a mass ratio of 1: 1: 8 to obtain a liquid crystal aligning agent of the present invention. Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Example 9]
As a tetracarboxylic dianhydride component, 7.84 g (40 mmol) of CA2 was used, 6.51 g (32 mmol) of DA1 was used as a diamine component, and 3.26 g (8 mmol) of DA3 was used. The reaction was performed for a time to obtain a polyamic acid solution. The number average molecular weight of this polyamic acid was 14,119, and the weight average molecular weight was 39,572. 10.5 g of NMP and 7.5 g of BC were added to 8 g of this solution and stirred at room temperature for 20 hours to obtain a uniform polyamic acid solution (PAA-4). This solution was used as a liquid crystal alignment treatment agent. Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Comparative Example 1]
As the tetracarboxylic dianhydride component, 13.38 g (45 mmol) of CA1 was used, and 3.89 g (36 mmol) of DA4 was used as the diamine component, and 3.67 g (9 mmol) of DA3 was used. The reaction was performed for a time to obtain a polyamic acid solution. 256.1 g of NMP was added to 98.5 g of this polyamic acid solution for dilution, 46.68 g of acetic anhydride and 21.71 g of pyridine were added, and the mixture was reacted at a temperature of 40 ° C. for 3 hours to imidize. The reaction solution was cooled to about room temperature and then poured into 1480.5 ml of methanol to recover the precipitated solid. The solid was washed several times with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a white powder of polyimide (SPI-T1). The number average molecular weight of this polyimide was 12,120, and the weight average molecular weight was 35,728. Moreover, the imidation ratio was 85%. 10.8 g of γBL was added to 1.2 g of this polyimide powder, and the mixture was stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After 12 g of this solution was cooled to 23 ° C., 2 g of γBL and 6 g of BC were added and stirred at a temperature of 50 ° C. for 20 hours. After the stirring, the mixture was cooled to 23 ° C. to obtain a uniform polyimide solution. This solution was used as a liquid crystal alignment treatment agent.
Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Comparative Example 2]
6.48 g (23 mmol) of CA1 and 5.63 g (23 mmol) of CA3 are used as the tetracarboxylic dianhydride component, 3.89 g (36 mmol) of DA4 and 3.67 g (9 mmol) of DA3 are used as the diamine component. , NMP 78.71 g, was reacted at 80 ° C. for 24 hours to obtain a polyamic acid solution. To 50 g of this polyamic acid solution, 110 g of NMP was added for dilution, and 6.45 g of acetic anhydride and 9.99 g of pyridine were added and reacted at a temperature of 100 ° C. for 3 hours to imidize. The reaction solution was cooled to about room temperature and then poured into 617.6 ml of methanol to recover the precipitated solid. The solid was washed several times with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a white powder of soluble polyimide (SPI-T2). The number average molecular weight of this polyimide was 12,105, and the weight average molecular weight was 74,076. The imidation ratio was 82%. 10.8 g of γBL was added to 1.2 g of this polyimide powder and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After 12 g of this solution was cooled to 23 ° C., 2 g of γBL and 6 g of BC were added and stirred at a temperature of 50 ° C. for 20 hours. After the stirring, the mixture was cooled to 23 ° C. to obtain a uniform polyimide solution. This solution was used as a liquid crystal alignment treatment agent.
Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Comparative Example 3]
As a tetracarboxylic dianhydride component, 8.07 g (42 mmol) of CA2 was used, 3.63 g (34 mmol) of DA4 was used as a diamine component, and 3.26 g (8 mmol) of DA3 was used. It was made to react for time and the polyamic acid (PAA-T1) solution was obtained. The number average molecular weight of this amic acid was 26,985, and the weight average molecular weight was 66,365. To 8 g of this solution, 10.5 g of NMP and 7.5 g of BC were added and stirred at room temperature for 20 hours to obtain a uniform polyamic acid solution. This solution was used as a liquid crystal alignment treatment agent.
Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Comparative Example 4]
Using 30.03 g (100 mmol) of CA1 as the tetracarboxylic dianhydride component, 9.73 g (90 mmol) of DA4 and 3.77 g (10 mmol) of DA2 as the diamine component, the reaction was carried out at 40 ° C. for 3 hours in 247 g of NMP. To obtain a polyamic acid solution.
50 g of this polyamic acid solution was diluted to 5% by weight with NMP, and 17.6 g of acetic anhydride and 8.2 g of pyridine were added as an imidization catalyst and reacted at 40 ° C. for 3 hours to prepare a soluble polyimide resin solution. . This solution was poured into 0.6 L of methanol, and the resulting precipitate was filtered off and dried to obtain a white soluble polyimide (SPI-T3). As a result of measuring the molecular weight of this soluble polyimide, the number average molecular weight was 13,430 and the weight average molecular weight was 26,952. Moreover, the imidation ratio was 85%. 1 g of this polyimide powder was dissolved in 11.8 g of γBL and 4.8 g of BC to obtain a uniform polyimide solution. This solution was used as a liquid crystal alignment treatment agent.
Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Comparative Example 5]
Using 5.59 g (29 mmol) of CA2 as a tetracarboxylic dianhydride component, 3.08 g (28 mmol) of DA4 and 0.571 g (1.5 mmol) of DA5 as a diamine component, room temperature in 83.18 g of NMP at room temperature For 24 hours to obtain a polyamic acid (PAA-T2) solution. The number average molecular weight of this polyamic acid was 17,630, and the weight average molecular weight was 41,068. To 12 g of this solution, 2 g of NMP and 6 g of BC were added and stirred at room temperature for 20 hours to obtain a uniform polyamic acid solution. This solution was used as a liquid crystal alignment treatment agent.
Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Comparative Example 6]
As the tetracarboxylic dianhydride component, 5.59 g (29 mmol) of CA2 and 2.43 g (23 mmol) of DA4, 0.571 g (1.5 mmol) of DA5 and 1.219 g (6 mmol) of DA1 as the diamine component. For 24 hours in NMP 83.18 g at room temperature to obtain a polyamic acid (PAA-T3) solution. The number average molecular weight of this polyamic acid was 16,132, and the weight average molecular weight was 34,880. To 12 g of this solution, 2 g of NMP and 6 g of BC were added and stirred at room temperature for 20 hours to obtain a uniform polyamic acid solution. This solution was used as a liquid crystal alignment treatment agent.
Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Comparative Example 7]
As tetracarboxylic dianhydride components, CA2 (13.53 g, 69 mmol), CA4 (6.54 g, 30 mmol), diamine components as DA10, 9.62 g (30 mmol), DA1 (6.10 g, 30 mmol), DA7 Was reacted at room temperature for 24 hours with NMP of 162.7 g to obtain a polyamic acid solution. To 35.79 g of this polyamic acid solution, 63.91 g of NMP was added for dilution, 5.16 g of acetic anhydride and 2.20 g of pyridine were added, and the mixture was reacted at 50 ° C. for 3 hours to imidize.
The reaction solution was cooled to about room temperature and then poured into 374.7 ml of methanol to recover the precipitated solid. The solid was washed several times with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a white powder of polyimide (SPI-T4). The number average molecular weight of this polyimide was 13,472, and the weight average molecular weight was 35,859. Further, the imidization ratio was 89%.
10.8 g of γBL was added to 1.2 g of this polyimide powder, and the mixture was stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After 12 g of this solution was cooled to 23 ° C., 2 g of γBL and 6 g of BC were added and stirred at a temperature of 50 ° C. for 20 hours. After stirring, the mixture was cooled to 23 ° C. to obtain a uniform liquid crystal aligning agent.
The SPI-T4 and SPI-4 were mixed at a mass ratio of 3: 7 to obtain a liquid crystal aligning agent of the present invention. Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

[Comparative Example 8]
As the tetracarboxylic dianhydride component, CA2 is 13.33 g (68 mmol), CA4 is 6.54 g (30 mmol), and as the diamine component, DA5 is 3.81 g (10 mmol), DA1 is 8.13 g (40 mmol), DA6 Was used to react with 151.7 g of NMP at room temperature for 24 hours to obtain a polyamic acid solution. 59.61 g of NMP was added to 33.38 g of this polyamic acid solution to dilute, 5.26 g of acetic anhydride and 2.24 g of pyridine were added, and the mixture was reacted at a temperature of 50 ° C. for 3 hours to imidize.
The reaction solution was cooled to about room temperature and then poured into 351.7 ml of methanol to recover the precipitated solid. The solid was washed several times with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a white powder of polyimide (SPI-T5). The number average molecular weight of this polyimide was 10,111, and the weight average molecular weight was 33,653. Moreover, the imidation ratio was 90%.
10.8 g of γBL was added to 1.2 g of this polyimide powder and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After 12 g of this solution was cooled to 23 ° C., 2 g of γBL and 6 g of BC were added and stirred at a temperature of 50 ° C. for 20 hours. After stirring, the mixture was cooled to 23 ° C. to obtain a uniform liquid crystal aligning agent.
The SPI-T5 and SPI-4 were mixed at a mass ratio of 3: 7 to obtain the liquid crystal aligning agent of the present invention. Using this liquid crystal aligning agent, rubbing resistance, orientation and tilt angle were evaluated. The results are shown in Table 2.

表1中、「−」は、該当するジアミンをポリアミック酸又はポリイミドの原料として使用していないことを表す。

In Table 1, “-” indicates that the corresponding diamine is not used as a raw material for polyamic acid or polyimide.

The liquid crystal display element produced using the liquid crystal aligning agent of this invention can be used as a highly reliable liquid crystal display device, such as a TN liquid crystal display element, an STN liquid crystal display element, a TFT liquid crystal display element, and an OCB liquid crystal display element. It is suitably used for display elements by various methods.

The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2008-272410 filed on October 22, 2008 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (9)

A polyamic acid obtained by reacting a diamine component and a tetracarboxylic dianhydride component and a soluble polyimide obtained by imidizing the polyamic acid contain at least one polymer, and the diamine component is represented by the formula [1]. The liquid crystal aligning agent characterized by containing the diamine represented by these, and the diamine represented by Formula [2].

(In the formula, n is an integer of 0 to 19.)   The liquid crystal aligning process of Claim 1 which the diamine represented by Formula [2] in a diamine component contains 0.1 mol-1.2 mol with respect to 1 mol of diamine represented by Formula [1]. Agent.   The liquid-crystal aligning agent of Claim 1 or 2 in which a diamine component contains 20 mol% or more of diamine represented by Formula [1].   The liquid-crystal aligning agent in any one of Claims 1-3 in which a diamine component contains 5-60 mol% of diamine represented by Formula [2].   The positional relationship between the two amino groups of the diamine represented by the formula [1] and the diamine represented by the formula [2] is the meta position or the para position, respectively. The liquid-crystal aligning agent in any one.   The liquid crystal aligning agent in any one of Claims 1-5 in which the tetracarboxylic dianhydride component contains the tetracarboxylic dianhydride which has an alicyclic structure or an aliphatic structure.   The liquid-crystal aligning agent in any one of Claims 1-6 in which a tetracarboxylic dianhydride component contains aromatic tetracarboxylic dianhydride.   The liquid crystal aligning film obtained by apply | coating and baking the liquid-crystal aligning agent in any one of Claims 1-7 on a board | substrate with an electrode, and carrying out a rubbing process.   The liquid crystal display element using the liquid crystal aligning film of Claim 8.