JP5713008B2 - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element using the same - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent that suppresses whitening and generation of foreign matter and does not decrease a pretilt angle, 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. In general, a liquid crystal alignment agent (also referred to as a liquid crystal alignment treatment agent) that forms a highly reliable polyimide film is used for the liquid crystal alignment film.
As a means for forming such a polyimide film on a substrate with electrodes, a method of forming a liquid crystal aligning agent coating film composed of a solution of a polyimide precursor such as polyamic acid and imidizing on the substrate, and imidizing in advance. And using a solution containing a certain polyimide.

Among them, the method using a polyimide-containing solution was able to form a polyimide film with good characteristics when used as a liquid crystal alignment film, even when firing at a relatively low temperature. The strength of the film is low, and the film surface is easily scratched or peeled off by an alignment process such as a rubbing process. Scratches and peeling on the surface of the liquid crystal alignment film are important because they cause display defects when the liquid crystal display element is formed.
On the other hand, the method of using a solution containing polyimide, polyimide is generally inferior in solubility in organic solvents compared to polyamic acid and the like, it may be difficult to form a uniform coating film, May become insoluble in a solvent usually used for a liquid crystal aligning agent and may be difficult to be contained in the liquid crystal aligning agent. Therefore, the solubility of the polyimide contained in the liquid crystal aligning agent is also important.

Further, when a liquid crystal aligning agent containing polyimide is used, when printing on a substrate or the like, polyimide is precipitated by moisture absorption, the varnish causes a whitening phenomenon, and surface roughness occurs in the resulting coating film.
Furthermore, in the case of a liquid crystal aligning agent containing polyimide, the polyimide has poor adhesion to a printing plate such as APR (Asahi Photosensitive Resin), and the coating film is peeled off from the printing plate in the printing process and transferred to the substrate as it is. As a result, the peeled polyimide remains on the substrate as a foreign substance, which tends to agglomerate and cause gap unevenness.

  In response to the above problems, a liquid crystal aligning agent containing a diamine component having a specific structure for improving the rubbing resistance of the liquid crystal alignment film and the solubility of polyimide has been proposed (see Patent Document 1). Further, as a method for suppressing the whitening phenomenon of a varnish containing polyimide, it has been proposed to use a high boiling point solvent capable of suppressing the drying time such as N-vinylpyrrolidone or N-cyclohexylpyrrolidone for 50% or more of the solvent. (See Patent Document 2).

International Publication No. 2006/126555 Pamphlet Japanese Patent Laid-Open No. 5-117487

  However, the conventional means proposed above are not always sufficient. For example, in the means using a high boiling point solvent in Patent Document 2, since these solvents are generally highly hygroscopic, the amount of use is small. It has been found that when it becomes large, the above-mentioned whitening phenomenon of the varnish of the liquid crystal aligning agent is increased, and the side effect of reducing the pretilt angle of the obtained liquid crystal aligning film is caused.

The whitening phenomenon in the liquid crystal aligning agent containing polyimide described above, the phenomenon of generating foreign matter on the substrate, and the decrease in the pretilt angle of the obtained liquid crystal alignment film have recently increased the size and resolution of liquid crystal display elements. Along with this, the demands for quality are becoming more and more important issues to be solved.
The present invention suppresses the whitening phenomenon and the phenomenon of generating foreign matter on the substrate in the liquid crystal alignment agent containing polyimide, and further suppresses the decrease in the pretilt angle of the obtained liquid crystal alignment film. Another object of the present invention is to provide a liquid crystal aligning agent that is also good.

As a result of intensive studies to achieve the above object, the present inventors have completed the present invention. That is, the gist of the present invention is as follows.
1. A polyimide obtained by imidizing a polyamic acid obtained by reacting a diamine component and tetracarboxylic dianhydride, and a polyol compound having 3 to 15 carbon atoms having tertiary nitrogen atoms and quaternary carbon atoms, A liquid crystal aligning agent characterized by containing.
2. 2. The liquid crystal aligning agent according to 1 above, wherein the polyol compound is represented by the following formula (A).

（式中のＲ¹、Ｒ²はそれぞれ独立に炭素数１〜５のヒドロキシアルキル基を表し、Ｒ³、Ｒ⁴、Ｒ⁵は、それぞれ独立に炭素数１〜５のアルキル基又は炭素数１〜５のヒドロキシアルキル基を表す。）
３．ポリオール化合物が、水酸基を２〜８個有する上記１又は２に記載の液晶配向剤。
４．ポリイミドを１〜１０質量％含有し、かつポリオール化合物をポリイミド１００質量部に対し０．１〜１０質量部を含有する上記１〜３のいずれかに記載の液晶配向剤。
５．ジアミン成分が、炭素数２又は３のアルケニル基で置換されたジ置換アミノ基を有するジアミノベンゼンである、上記１〜４のいずれかに記載の液晶配向剤。
６．ジアミノベンゼンが、下記の式［１］で表されるジアミンである、上記５に記載の液晶配向剤。

(In the formula, R ¹ and R ² each independently represent a hydroxyalkyl group having 1 to 5 carbon atoms, and R ³ , R ⁴ and R ⁵ are each independently an alkyl group having 1 to 5 carbon atoms or 1 carbon atom. Represents a hydroxyalkyl group of ˜5.)
3. 3. The liquid crystal aligning agent according to 1 or 2 above, wherein the polyol compound has 2 to 8 hydroxyl groups.
4). The liquid crystal aligning agent in any one of said 1-3 which contains 1-10 mass% of polyimides, and contains a polyol compound 0.1-10 mass parts with respect to 100 mass parts of polyimides.
5. 5. The liquid crystal aligning agent according to any one of 1 to 4 above, wherein the diamine component is diaminobenzene having a disubstituted amino group substituted with an alkenyl group having 2 or 3 carbon atoms.
6). 6. The liquid crystal aligning agent according to 5 above, wherein the diaminobenzene is a diamine represented by the following formula [1].

７．ジアミン成分が、さらに、下記の式［32］で表されるジアミンを含む、上記６に記載の液晶配向剤。

7). 7. The liquid crystal aligning agent according to 6 above, wherein the diamine component further contains a diamine represented by the following formula [32].

（上記式中、ｋは１〜２０の整数を表す。）
８．式［１］で表されるジアミンを、全ジアミン成分中２０〜９０モル％含有する上記６又は７のいずれかに記載の液晶配向剤。
９．さらに、式［３２］で表されるジアミンが、全ジアミン成分中５〜４０モル％含有される、上記７又は８のいずれかに記載の液晶配向剤。
１０．上記１〜９のいずれかに記載の液晶配向剤を電極付き基板上に塗布、焼成して得られる液晶配向膜。
１１．上記１０に記載の液晶配向膜を有する液晶表示素子。

(In the above formula, k represents an integer of 1 to 20.)
8). The liquid crystal aligning agent in any one of said 6 or 7 which contains 20-90 mol% of diamine represented by Formula [1] in all the diamine components.
9. Furthermore, the liquid crystal aligning agent in any one of said 7 or 8 containing 5-40 mol% of diamine represented by Formula [32] in all the diamine components.
10. The liquid crystal aligning film obtained by apply | coating and baking the liquid crystal aligning agent in any one of said 1-9 on a board | substrate with an electrode.
11. 11. A liquid crystal display device having the liquid crystal alignment film as described in 10 above.

According to the liquid crystal aligning agent of the present invention, whitening phenomenon or foreign matter is generated on the substrate, and the phenomenon that the foreign matter aggregates to cause gap unevenness is suppressed, and further, the pretilt angle of the obtained liquid crystal alignment film is reduced. A liquid crystal alignment film that is suppressed and has good alignment properties can be obtained, and by using such a liquid crystal alignment film, a highly reliable liquid crystal display element can be produced with a high yield even in the case of large size and high definition.
Mechanism of why the use of the liquid crystal aligning agent of the present invention can suppress the phenomenon of whitening and the generation of foreign matter on the substrate, and further suppress the decrease in the pretilt angle of the liquid crystal alignment film obtained. Is not necessarily clear, but is considered as follows.
The polyol compound contained in the liquid crystal aligning agent of the present invention is resistant to whitening as a result of increasing the solubility of the polymer containing polyimide in water by forming a salt with the carboxylic acid group in the polymer. Is thought to improve. In addition, due to the presence of a large number of hydroxyl groups in the polyol compound, the adhesion between the polymer containing polyimide and the APR plate is improved, so that foreign matter is generated due to film peeling during printing and the resulting gap unevenness of the liquid crystal display element. It is thought that it can be suppressed.

  The liquid crystal aligning agent of this invention contains the polyimide obtained by imidizing the polyamic acid obtained by making a diamine component and tetracarboxylic dianhydride react as a polymer. Although the polyimide used for this invention is not specifically limited, It is obtained as follows.

[Diamine component]
The diamine component (also simply referred to as diamine) used for obtaining the polyimide is not particularly limited. The diamine can be used alone or in combination, and the type is not limited. Examples of the diamine include alicyclic diamines, aromatic diamines, heterocyclic diamines, and aliphatic diamines. Specific examples are shown below.

  Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4′-diaminodicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexylamine, and 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 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-diaminododecane 1,18-diaminooctadecane, 1,2-bis (3-aminopropoxy) ethane and the like.

  In the present invention, diaminobenzene having a disubstituted amino group substituted with an alkenyl group having 2 or 3 carbon atoms (hereinafter also referred to as a specific diamine) is preferably used as the diamine. When a specific diamine is used, the solubility of the polymer is increased and the generation of foreign matters can be further suppressed. As the specific diamine, diaminobenzene having a disubstituted amino group substituted with a 2-propenyl group (hereinafter also referred to as an allyl group) represented by the following formula [1] is particularly preferable.

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またはパラが好ましい。以下にこのジアミンのより好ましい具体例を挙げる。

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. The more preferable specific example of this diamine is given below.

前記式［２］は、２，４−ジアミノ−N，N−ジアリルアニリンであり、前記式［３］は、３，５−ジアミノ−N，N−ジアリルアニリンであり、前記式［４］は、２，５−ジアミノ−N，N−ジアリルアニリンである。前記ジアミノベンゼンは、前記［２］、［３］及び［４］からなる群から選ばれる少なくとも一種であるのがより好ましい。なかでも、前記ジアミノベンゼンは、２，４−ジアミノ−N，N−ジアリルアニリンであるのが特に好ましい。

The formula [2] is 2,4-diamino-N, N-diallylaniline, the formula [3] is 3,5-diamino-N, N-diallylaniline, and the formula [4] is 2,5-diamino-N, N-diallylaniline. More preferably, the diaminobenzene is at least one selected from the group consisting of [2], [3] and [4]. Of these, the diaminobenzene is particularly preferably 2,4-diamino-N, N-diallylaniline.

  In the present invention, the diamine component used as a raw material for polyimide may be only a specific diamine, or a combination of a specific diamine and one or more of other diamines. By making a diamine component for obtaining a polyimide contain a specific diamine, the solubility of the polyimide in an organic solvent is increased. Furthermore, problems such as scratches on the film surface and film peeling when the coating film is rubbed are improved.

  The content of the specific diamine in the diamine component is preferably 20 mol (mol)% or more, more preferably 40 mol% or more, and particularly 50 mol% or more. The higher the specific diamine content ratio in the diamine component, the higher the effect of suppressing scratches on the alignment film surface and the film peeling during the rubbing treatment. Moreover, the solubility with respect to the organic solvent of the polyimide obtained also becomes high. On the other hand, the diamine component may be only the specific diamine, but it is preferable to use a diamine other than the specific diamine because other characteristics required for the liquid crystal alignment film can be imparted. Therefore, the content of the specific diamine is more preferably 90 mol% or less. In particular, when a specific diamine and 4-aminobenzylamine, 3-aminobenzylamine, or 4-aminophenethylamine are used, the solubility of polyimide in an organic solvent is increased, and a liquid crystal aligning agent having excellent liquid crystal alignment is obtained. Therefore, it is particularly preferable. The preferred content of 4-aminobenzylamine, 3-aminobenzylamine, or 4-aminophenethylamine in the diamine component is 10 mol% to 50 mol%.

  In order to increase the pretilt angle of the liquid crystal, a diamine having a specific substituent can be used in combination. As the substituent capable of increasing the pretilt angle of the liquid crystal, a long-chain alkyl group, a perfluoroalkyl group, an aromatic cyclic group, an aliphatic cyclic group, a combination of these, or a steroid skeleton group is preferable. Although the specific example of the diamine which has the said substituent is given to the following, it is not limited to this. In the structures exemplified below, j represents an integer of 5 to 20, preferably 9 to 17, and k represents an integer of 1 to 20, preferably 4 to 15.

  Among the above diamines, the diamines of the formulas [5] and [32] are preferable because of excellent liquid crystal alignment. Since the diamines represented by the formulas [12] to [19] have a very high ability to develop a tilt, they are suitably used for OCB (Optically Compensated Bend) alignment films and VA (Vertical Alignment) alignment films. As a preferred example, in a TN (twisted nematic) alignment film (pretilt is 3 to 5 °), the diamine of formula [5] or [32] is 5 to 40 mol%, preferably 10 to 30 mol% in the diamine component. In the OCB and VA alignment film (pretilt 10 to 90 °), the diamine of formula [12] to [19] is contained in the diamine component in an amount of 5 to 60 mol%, preferably 10 to 40 mol%. Can be mentioned.

  Among the above diamines, the diamine of formula [32] is particularly preferable because it has a high tilt angle and is excellent in liquid crystal alignment even when the rubbing conditions are weak when used in combination with the specific diamine. . Furthermore, the effect of increasing the pretilt angle of the liquid crystal as described above tends to be weakened when the liquid crystal aligning agent contains a large amount of N-ethyl-2-pyrrolidone or N-cyclohexyl-2-pyrrolidone. However, the diamine of the formula [32] has a characteristic that it is not easily affected by the above, and is suitable as a diamine component of the polyimide contained in the liquid crystal aligning agent of the present invention.

[Tetracarboxylic dianhydride component]
In the present invention, the tetracarboxylic dianhydride component used as a raw material for polyimide may be one type of tetracarboxylic dianhydride or a mixture of two or more types of tetracarboxylic dianhydrides. good.
However, even if it is a polyimide with a high imidization rate, a tetracarboxylic acid having an alicyclic structure or an aliphatic structure can be obtained because it is easy to obtain a polyimide with relatively high solubility and the voltage holding ratio of the liquid crystal cell can be increased. It is preferable to use an acid dianhydride.

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-like dianhydride.

  Examples of tetracarboxylic dianhydrides having an alicyclic structure or an aliphatic structure include 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 3,4-dicarboxy-1,2,3,4. Use of tetrahydro-1-naphthalene succinic dianhydride or 1,2,3,4-butanetetracarboxylic dianhydride is particularly preferable because an alignment film having excellent liquid crystal alignment can be obtained.

  Furthermore, when an aromatic tetracarboxylic dianhydride is used in combination with a tetracarboxylic dianhydride having an alicyclic structure or an aliphatic structure, the liquid crystal alignment is improved and the accumulated charge of the liquid crystal cell is reduced. This 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.

  As aromatic tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, among others Or 1,4,5,8-naphthalenetetracarboxylic dianhydride is particularly preferred.

  Considering the balance of properties such as polyimide solubility, liquid crystal orientation, voltage holding ratio, accumulated charge, tetracarboxylic dianhydride having an alicyclic structure or aliphatic structure, and aromatic tetracarboxylic The ratio with the acid dianhydride is preferably 90/10 to 50/50, more preferably 80/20 to 60/40 in terms of the former / the latter molar ratio.

[Polyimide and its production method]
The polyimide used for the liquid crystal aligning agent of this invention is a polyimide which imidized the polyamic acid obtained by making the above-mentioned diamine component and the tetracarboxylic dianhydride component react. Here, the polyamic acid can be obtained by mixing and reacting a tetracarboxylic dianhydride component and a diamine component in an organic solvent.

  As a method of mixing the tetracarboxylic dianhydride component and the diamine component in an organic solvent, a solution in which the diamine component is dispersed or dissolved in the organic solvent is stirred, and the tetracarboxylic dianhydride component is used as it is or in an organic solvent. 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. When the tetracarboxylic dianhydride component or the diamine component is composed of a plurality of types of compounds, the plurality of types of components may be preliminarily mixed, or may be individually polymerized sequentially.

  The temperature at which the tetracarboxylic dianhydride component and the diamine component are subjected to a polymerization reaction in an organic solvent is usually 0 to 150 ° C, preferably 5 to 100 ° C, more preferably 10 to 80 ° C. When the temperature is higher, the polymerization reaction is completed earlier, but when it is too high, a high molecular weight polymer may not be obtained.

  The polymerization reaction can be carried out at any concentration, but if the concentration is too low, it will be difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution will become too high and uniform stirring will occur. Since it becomes difficult, the density | concentration of the total amount of a tetracarboxylic dianhydride component and a diamine component becomes like this. Preferably it is 1-50 mass%, More preferably, it is 5-30 mass%. The initial stage of the polymerization 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 produced polyamic acid can be dissolved, but N-ethyl-2-pyrrolidone or N-cyclohexyl-2-pyrrolidone, or other solvent is used. Also good. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylphosphoric acid. Triamide, γ-butyrolactone, 1,3-dimethylimidazolidinone and the like can be mentioned. 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. In addition, since water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the generated 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 polymerization reaction of the polyamic acid is preferably 1: 0.8 to 1: 1.2 in terms of molar ratio, and this molar ratio is close to 1: 1. The molecular weight of the polyamic acid obtained increases. By controlling the molecular weight of this polyamic acid, the molecular weight of the polyimide obtained after imidation can be adjusted.

Although the molecular weight of the polyimide contained in the liquid crystal aligning agent of this invention is not specifically limited, From a viewpoint of the intensity | strength of a coating film and the ease of handling as a liquid crystal aligning agent, 2,000-200,000 are weight average molecular weights. Preferably, it is 5,000 to 50,000.
The imidization of the polyamic acid obtained as described above can be performed by stirring in an organic solvent for 1 to 100 hours in the presence of a basic catalyst and an acid anhydride.

  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 polyamic acid polymerization reaction mentioned above can be used.

  The imidation ratio of 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 of the raw polyamic acid. Moreover, 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 of the raw polyamic acid. The reaction temperature is preferably -20 to 250 ° C, more preferably 0 to 180 ° C.

The imidization ratio of the polyimide contained in the liquid crystal aligning agent of the present invention is not particularly limited, but is preferably 40% or more in consideration of electrical characteristics, and more preferably 60% or more in order to obtain a high voltage holding ratio. More preferably, it is 80% or more.
Since the added catalyst or the like remains in the polyimide solution thus obtained, the polyimide is preferably recovered and washed before use in the liquid crystal aligning agent of the present invention.

The 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 polyimide can also 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.

[Polyol compound having tertiary nitrogen and quaternary carbon]
The liquid crystal aligning agent of the present invention contains a polyol compound having tertiary nitrogen and quaternary carbon. Such a polyol compound needs to have tertiary nitrogen and quaternary carbon, and when it does not have both, the above-mentioned object of the present invention is not achieved or the degree to which it is achieved becomes small. For example, as shown in a comparative example described later, the above-described object of the present invention is achieved in the case of triethanolamine having a plurality of hydroxyl groups and a tertiary nitrogen atom but not having a quaternary carbon atom. Not.

  The total carbon number of the polyol compound is required to be 3 to 15, preferably 3 to 13, and more preferably 6 to 12. The number of hydroxyl groups possessed by the polyol compound is important, and the number of hydroxyl groups is preferably 2 to 8, more preferably 2 to 7, and particularly preferably 2 to 5. When the number of hydroxyl groups is too large, the display characteristics of the liquid crystal display element are deteriorated. On the other hand, when the amount is too small, the adhesion with the APR plate is deteriorated. The number of tertiary nitrogen atoms and quaternary carbon atoms may be one or more, preferably 5 or less, and more preferably 3 or less. The polyol compound preferably has an aliphatic saturated hydrocarbon structure. However, when the total number of carbon atoms is large, the polyol compound may partially have an unsaturated bond, and may partially have a cyclic structure. You may have a structure.

上記式（Ａ）において、Ｒ¹、Ｒ²は、それぞれ独立に、炭素数１〜５、好ましくは１〜３のヒドロキシアルキル基を表し、Ｒ³、Ｒ⁴、Ｒ⁵は、それぞれ独立に、炭素数１〜５、好ましくは１〜３のアルキル基、又は炭素数１〜５、好ましくは１〜３のヒドロキシアルキル基を表す。Such a polyol compound is preferably a compound represented by the following formula (A).

In the above formula (A), R ¹ and R ² each independently represents a hydroxyalkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and R ³ , R ⁴ and R ⁵ are each independently An alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, or a hydroxyalkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms.

Preferable examples of the compound represented by the formula (A) include the following compounds.

[Liquid crystal aligning agent]
The liquid crystal aligning agent of the present invention comprises the aforementioned polyimide as a polymer component, a polyol compound having tertiary nitrogen and quaternary carbon as an additional component, and these are dissolved in a solvent. 0.1-10 mass parts is preferable with respect to 100 mass parts of polyimides, and, as for content of the polyol compound with respect to the polyimide in a liquid crystal aligning agent, 0.5-5 mass parts is more preferable. When the polyol compound is excessively contained, the characteristics of the obtained liquid crystal display element are deteriorated. Conversely, when the amount is too small, the effect intended by the present invention is small.

  The content (concentration) of the polyimide in the liquid crystal aligning agent can be appropriately changed depending on the thickness of the liquid crystal alignment film to be formed, but the solvent is preferably 9 to 99 parts by mass with respect to 1 part by mass of the polyimide. The amount is preferably 11.5 to 49 parts by mass. When the amount of the solvent is more than 99 parts by mass, it is difficult to form a uniform and defect-free coating film. Conversely, when the amount is less than 9 parts by mass, the storage stability of the solution may be deteriorated. The content of the solvent in the liquid crystal aligning agent of the present invention is preferably 90 to 99% by mass, more preferably 92 to 98 parts by mass with respect to the entire liquid crystal aligning agent.

  As the solvent used in the liquid crystal aligning agent of the present invention, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-vinylpyrrolidone, dimethyl Examples thereof include sulfoxide, tetramethylurea, dimethylsulfone, hexamethylsulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone. Of these, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, and γ-butyrolactone are preferably used because of the high solubility of polyimide. Further, γ-butyrolactone is preferably used for suppressing whitening.

  Further, when N-ethyl-2-pyrrolidone or N-cyclohexyl-2-pyrrolidone is contained as a solvent used in the liquid crystal aligning agent of the present invention, the coating film is whitened and the film thickness is uneven near the printing edge. Since it can suppress, it is preferable. When the amount of these solvents is 0.5 parts by mass or more with respect to 1 part by mass of the polymer, an improvement effect for suppressing the generation of aggregates is observed, preferably 1 to 80 parts by weight, more preferably 2 parts by weight. -70 parts by weight.

  The polyimide contained in the liquid crystal aligning agent of the present invention may be a mixture of two or more kinds of polyimides having different structures, does not impair electrical characteristics, does not deteriorate the storage stability of the varnish, and is printed. A polyamic acid or other polymer may be used in combination so as not to generate aggregates that sometimes cause gap unevenness in the liquid crystal panel. The amount of the polymer to be used in combination is preferably 0.05 to 7 parts by mass, more preferably 0.1 to 4 parts by mass with respect to 1 part by mass of the polyimide. The content of the polymer containing polyimide in the liquid crystal aligning agent of the present invention is preferably 1 to 10% by mass, more preferably 2 to 8% by mass of the entire liquid crystal aligning agent.

As a solvent used for the liquid crystal aligning agent of this invention, the solvent which has a low surface tension can also partially contain. By appropriately mixing a solvent having a low surface tension with the solvent component, the coating film uniformity can be improved during application to the substrate.
As the solvent having a low surface tension, 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, diethylene glycol diethyl ether, propylene glycol monoacetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-mono Ethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester Lactate n- propyl ester, lactate n- butyl ester, and the like lactic isoamyl ester. Among these, butyl cellosolve, ethyl carbitol, dipropylene glycol monomethyl ether, or diethylene glycol diethyl ether is particularly preferable from the viewpoint of applicability to the substrate.

  A solvent having a low surface tension improves the coating property to the substrate, but if the amount is too large, precipitation of the polymer occurs, so the content is preferably 60% by mass or less, more preferably 50% by mass or less of the solvent component. It is. When using in combination the solvent for ensuring the solubility of the resin component and the solvent having a low surface tension, the more preferable content of each solvent is 5 to 70% by mass of the solvent for ensuring the solubility of the resin component. Yes, the solvent having a low surface tension is 10 to 60% by mass, more preferably the solvent for ensuring the solubility of the resin component is 10 to 45% by mass, and the solvent having a low surface tension is 20 to 50% by mass. %.

  The liquid crystal aligning agent of the present invention includes silane couplings such as 3-aminopropylmethyldiethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, and the like. Agents. By adding these silane coupling agents, the adhesion of the coating film to the substrate can be further improved. Content of a silane coupling agent becomes like this. Preferably it is 0.1-20 mass parts with respect to 100 mass parts of a polymer, More preferably, it is 0.2-10 mass parts.

[Method for preparing liquid crystal aligning agent]
The preparation method of the liquid crystal aligning agent of this invention will not be specifically limited if each component including above-mentioned polyimide will be in a uniform state in a liquid crystal aligning agent. One example is a method in which polyimide powder is dissolved in a solvent to obtain a polyimide solution, and then the solvent is added to a desired concentration for dilution. 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. The liquid crystal aligning agent obtained as described above is preferably filtered before being applied to the substrate.

The liquid crystal aligning agent of this invention can be made into a coating film by apply | coating to a board | substrate, drying and baking, and is used as a liquid crystal aligning film for rubbing by rubbing this coating-film surface. Further, it is also used as a VA liquid crystal alignment film or a photo alignment film instead of the rubbing treatment.
At this time, 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. Further, in the reflective liquid crystal display element, an opaque material 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 metal aluminum can be used as the electrode.

Examples of the method for applying the liquid crystal aligning agent include a spin coating method, a printing method, and an ink jet method, but the flexographic printing method is widely used industrially from the viewpoint of productivity. In the liquid crystal aligning agent of the present invention, Are also preferably used.
The drying process after applying the liquid crystal aligning 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, a drying process is included. Is preferred. The 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 the conveyance of 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.

Although baking of the board | substrate which apply | coated the liquid crystal aligning agent can be performed at 100-350 degreeC arbitrary temperatures, Preferably it is 150 to 300 degreeC, More preferably, it is 180 to 250 degreeC. When an amic acid group is present in the liquid crystal aligning agent, the calcination temperature changes from an amic acid to an imide, but in this case, it is not always necessary to 100% imidize.
The thickness of the coating film after baking is disadvantageous in terms of power consumption of the liquid crystal display element if it is too thick, 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. To give an example of the production of a liquid crystal cell, a pair of substrates on which a liquid crystal alignment film is formed is preferably 1 to 30 μm, more preferably 2 to 10 μm across an alignment treatment direction of 0 to 270 °. A method is generally used in which the angle is set at an arbitrary angle, 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 elements thus obtained include various types such as TN liquid crystal display elements, STN liquid crystal display elements, TFT liquid crystal display elements, OCB liquid crystal display elements, lateral electric field type liquid crystal display elements, and VA liquid crystal display elements. It is suitably used for a display element by the method.

The present invention will be described in more detail with reference to the following examples, but the present invention should not be construed as being limited thereto.
Abbreviations used in Examples and Comparative Examples are as follows.
<Tetracarboxylic dianhydride>
A-1: 1,2,3,4-cyclobutanetetracarboxylic dianhydride A-2: pyromellitic dianhydride

<Diamine>
B-1: 2,4-Diamino-N, N-diallylaniline

Ｂ−４：４−テトラデシルオキシー１，３−ジアミノベンゼンB-2: 3-aminobenzylamine B-3: 4- (trans-4-pentylcyclohexyl) benzamide-2 ′, 4′-phenylenediamine

B-4: 4-tetradecyloxy-1,3-diaminobenzene

化合物-２：N-tert-ブチルジエタノールアミン

<Additives>
Compound-1: Bis (2-hydroxyethyl) aminotris (hydroxymethyl) methane

Compound-2: N-tert-butyldiethanolamine

化合物-４： プロピルアミン

Compound-3: Triethanolamine

Compound-4: Propylamine

<Organic solvent>
NMP: N-methyl-2-pyrrolidone NEP: N-ethyl-2-pyrrolidone GBL: γ-butyrolactone DMI: 1,3-dimethylimidazolidinone BS: Butyl cellosolve

<Measurement of molecular weight>
The molecular weight of the polyimide was measured with a GPC (normal temperature gel permeation chromatography) apparatus, and the number average molecular weight and 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 additives, lithium bromide-hydrate (LiBr · H ₂ O) 30 mmol / l, phosphoric acid / anhydrous crystal (o-phosphoric acid) 30 mmol / l, tetrahydrofuran (THF) is 10 ml / l)
Flow rate: 1.0 ml / min Standard sample for preparing calibration curve: TSK standard polyethylene oxide (weight average molecular weight: about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene manufactured by Polymer Laboratories Glycol (weight average molecular weight about 12,000, 4,000, 1,000).

<Measurement of imidization ratio>
The imidation ratio of polyimide was measured as follows. 20 mg of the polyimide powder was put in an NMR sample tube, and 0.53 ml of deuterated dimethyl sulfoxide (DMSO-d ₆ , 0.05% TMS mixed product) was added and completely dissolved. 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 a structure that does not change before and after imidation as a reference proton, and the peak integrated value of this proton and the proton peak integrated value derived from the NH group of the amic acid that appears in the vicinity of 9.5 to 10.0 ppm. Was obtained 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.

Example 1
As tetracarboxylic dianhydride component, A-1 was 13.53 g (0.069 mol), A-2 was 6.54 g (0.030 mol), and diamine component was B-1 6.10 g (0.030 mol). ), 4.89 g (0.040 mol) of B-2 and 9.62 g (0.030 mol) of B-4, and reacted for 24 hours at room temperature in 162.7 g of NMP to obtain a polyamic acid solution.
The polyamic acid solution 142.8 g was diluted with 255.64 g of NMP, and 20.64 g of acetic anhydride and 8.8 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 1498.8 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-1). The number average molecular weight of this polyimide was 13,653, and the weight average molecular weight was 33,847. Moreover, the imidation ratio was 90%.
65 g of GBL was added to 5 g of the obtained polyimide SPI-1 powder and completely dissolved, then 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After returning this to room temperature, 0.25 g of Compound-1 was added and stirred for 3 hours to obtain a liquid crystal aligning agent.

(Example 2)
After adding 65 g of NMP to 5 g of polyimide SPI-1 powder and completely dissolving it, 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After returning this to room temperature, 0.25 g of Compound-1 was added and stirred for 3 hours to obtain a liquid crystal aligning agent.
(Example 3)
65 g of NEP was added to 5 g of polyimide SPI-1 powder and completely dissolved, and then 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After returning this to room temperature, 0.25 g of Compound-1 was added and stirred for 3 hours to obtain a liquid crystal aligning agent.

Example 4
As tetracarboxylic dianhydride component, A-1 was used in 8.18 g (42 mmol), A-2 was used in 1.63 g (7.5 mmol), and diamine component was used in B-2 as 1.22 g (10 mmol). Using 5.08 g (25 mmol) of B-1 and 6.11 g (15 mmol) of B-3, the mixture was reacted in 88.96 g of NMP at room temperature 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. 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 soluble polyimide (SPI-2). 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%.
65 g of GBL was added to 5 g of the obtained polyimide SPI-2 powder and completely dissolved, then 30 g of BS was added, 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 returning this to room temperature, 0.25 g of Compound-1 was added and stirred for 3 hours to obtain a liquid crystal aligning agent.

(Example 5)
After adding 65 g of NMP to 5 g of polyimide SPI-2 powder and completely dissolving it, 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After returning this to room temperature, 0.25 g of Compound-1 was added and stirred for 3 hours to obtain a liquid crystal aligning agent.
(Example 6)
65 g of NEP was added to 5 g of polyimide SPI-2 powder and completely dissolved, and then 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After returning this to room temperature, 0.25 g of Compound-1 was added and stirred for 3 hours to obtain a liquid crystal aligning agent.

(Example 7)
After adding 65 g of GBL to 5 g of polyimide SPI-1 powder and completely dissolving it, 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After returning this to room temperature, 0.25 g of compound-2 was added and stirred for 3 hours.
(Example 8)
65 g of NMP was added to 5 g of polyimide SPI-1 powder and completely dissolved, and then 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After returning this to room temperature, 0.25 g of compound-2 was added and stirred for 3 hours.
(Comparative Example 1)
After adding 65 g of GBL to 5 g of polyimide SPI-1 powder and completely dissolving it, 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours to obtain a liquid crystal aligning agent. The polyimide was completely dissolved at the end of stirring.
(Comparative Example 2)
After adding 65 g of NMP to 5 g of polyimide SPI-1 powder and completely dissolving it, 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours to obtain a liquid crystal aligning agent. The polyimide was completely dissolved at the end of stirring.

(Comparative Example 3)
After adding 65 g of NEP to 5 g of polyimide SPI-1 powder and completely dissolving it, 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours to obtain a liquid crystal aligning agent. The polyimide was completely dissolved at the end of stirring.
(Comparative Example 4)
After adding 65 g of GBL to 5 g of polyimide SPI-1 powder and completely dissolving it, 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours to obtain a liquid crystal aligning agent. The polyimide was completely dissolved at the end of stirring. After returning this to room temperature, 0.25 g of compound-3 was added and stirred for 3 hours to obtain a liquid crystal aligning agent.
(Comparative Example 5)
65 g of NMP was added to 5 g of polyimide SPI-1 powder and completely dissolved, and then 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After returning this to room temperature, 0.25 g of compound-3 was added and stirred for 3 hours.

(Comparative Example 6)
After adding 65 g of GBL to 5 g of polyimide SPI-2 powder and completely dissolving it, 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours to obtain a liquid crystal aligning agent. The polyimide was completely dissolved at the end of stirring.
(Comparative Example 7)
After adding 65 g of NEP to 5 g of polyimide SPI-2 powder and completely dissolving it, 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours to obtain a liquid crystal aligning agent. The polyimide was completely dissolved at the end of stirring.

(Comparative Example 8)
After adding 65 g of GBL to 5 g of polyimide SPI-2 powder and completely dissolving it, 30 g of BS was added and stirred at a temperature of 50 ° C. for 24 hours. The polyimide was completely dissolved at the end of stirring. After returning this to room temperature, 0.25 g of compound-4 was added and stirred for 3 hours to obtain a liquid crystal aligning agent.

  About the Examples 1-8 obtained by the above and Comparative Examples 1-8 liquid crystal aligning agent, the measurement of the chilled angle, evaluation of the whitening characteristic, and the foreign material evaluation at the time of printing were performed as follows. The results are shown in Tables 1 and 2.

<Measurement of pretilt angle>
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.
The pretilt angle was measured using the liquid crystal cell obtained by the above method. For the measurement, TBA107 manufactured by autotronic was used.

<Evaluation of whitening characteristics>
About 0.1 ml of the above liquid crystal aligning agent was dropped on each Cr substrate and left in an environment of a temperature of 23 ° C. and a humidity of 70%. The vicinity of the end and the center of the droplet were observed with a microscope every hour. The observation was performed at a magnification of 100 times near the edge of the droplet and at a magnification of 50 times near the center of the droplet. If aggregates are observed near the edge and center of the droplet within 6 hours, X is indicated when no aggregation is observed even after 6 hours, and aggregation is slightly observed at the edge of the droplet within 6 hours. When a thing was seen, it evaluated as (triangle | delta). The results are shown in Table 2.
<Foreign matter evaluation during printing>
Printing was performed using the same apparatus as described above. After performing the idling 10 times, the printing machine was stopped for 10 minutes and the printing plate was dried. Thereafter, one Cr substrate was printed and fired in the same manner as described above. The fired substrate was observed with a confocal laser microscope (trade name: VL2000, manufactured by Lasertec Co., Ltd.) in the vicinity of the printing edge, and in the vicinity of the printing edge, no foreign matter was generated. △ was evaluated as x when a foreign matter of 3 μm or more was generated. The results are shown in Table 2.

表中の括弧内の値は、ＧＢＬ主溶媒系と比較した際のプレチルト角の低下の値を表わす。

The value in parentheses in the table represents the value of decrease in pretilt angle when compared to the GBL main solvent system.

  The liquid crystal display element produced using the liquid crystal aligning agent of the present invention can be 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, an OCB liquid crystal display element, It is suitably used for display elements using various methods.

Claims (13)

  A polyimide obtained by imidizing a polyamic acid obtained by reacting a diamine component and tetracarboxylic dianhydride, and a polyol compound having 3 to 15 carbon atoms having tertiary nitrogen atoms and quaternary carbon atoms, A liquid crystal aligning agent characterized by containing. The liquid crystal aligning agent of Claim 1 by which a polyol compound is represented by a following formula (A).

(In the formula, R ¹ and R ² each independently represent a hydroxyalkyl group having 1 to 5 carbon atoms, and R ³ , R ⁴ and R ⁵ are each independently an alkyl group having 1 to 5 carbon atoms or 1 carbon atom. Represents a hydroxyalkyl group of ˜5.)   The liquid crystal aligning agent according to claim 1 or 2, wherein the polyol compound is a compound having 2 to 8 hydroxyl groups. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein the polyol compound is any one of the following compounds.

  The liquid crystal aligning agent in any one of Claims 1-4 which contains a 0.1-10 mass part polyol compound with respect to 100 mass parts of polyimides.   The liquid crystal aligning agent in any one of Claims 1-5 whose diamine component is diaminobenzene which has a disubstituted amino group substituted by the C2-C3 alkenyl group. The liquid crystal aligning agent of Claim 6 whose diaminobenzene is diamine represented by following formula [1].

The liquid crystal aligning agent of Claim 7 in which a diamine component contains the diamine represented by following formula [32] further.

(In the above formula, k represents an integer of 1 to 20.)   The liquid crystal aligning agent in any one of Claim 7 or 8 which contains 20-90 mol% of diamine represented by Formula [1] in all the diamine components.   Furthermore, the liquid crystal aligning agent in any one of Claim 8 or 9 with which the diamine represented by Formula [32] is contained 5-40 mol% in all the diamine components.   The content of the polymer containing polyimide is 1 to 10% by mass in the liquid crystal aligning agent containing the solvent.   The liquid crystal aligning film obtained by apply | coating and baking the liquid crystal aligning agent in any one of Claims 1-11 on a board | substrate with an electrode.   The liquid crystal display element which has a liquid crystal aligning film of Claim 12.