JP6278216B2 - Liquid crystal aligning agent, liquid crystal aligning film, 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, and a liquid crystal display element using the same used in a liquid crystal display element driven by applying a parallel electric field to a substrate.

  Conventionally, liquid crystal devices have been widely used as display units for personal computers, mobile phones, television receivers, and the like. The liquid crystal device includes, for example, a liquid crystal layer sandwiched between an element substrate and a color filter substrate, a pixel electrode and a common electrode that apply an electric field to the liquid crystal layer, an alignment film that controls the alignment of liquid crystal molecules in the liquid crystal layer, and a pixel electrode A thin film transistor (TFT) or the like for switching an electric signal supplied to the device is provided. As a driving method of liquid crystal molecules, a vertical electric field method such as a TN method and a VA method, and a horizontal electric field method such as an IPS method and an FFS method are known. In general, the lateral electric field method in which an electrode is formed only on one side of the substrate and an electric field is applied in a direction parallel to the substrate is compared with a conventional vertical electric field method in which a liquid crystal is driven by applying a voltage to the electrodes formed on the upper and lower substrates. It is known as a liquid crystal display device having a wide viewing angle characteristic and capable of high-quality display.

  Although the horizontal electric field type liquid crystal cell has excellent viewing angle characteristics, since there are few electrode parts formed in the substrate, if the voltage holding ratio of the liquid crystal alignment film is weak, sufficient voltage is not applied to the liquid crystal and the display contrast Decreases. In addition, static electricity is easily accumulated in the liquid crystal cell, and charges are accumulated in the liquid crystal cell by application of an asymmetric voltage generated by driving, and these accumulated charges disturb the alignment of the liquid crystal, or afterimages and image sticking. The display quality of the liquid crystal element is significantly reduced. Further, in the initial stage where the current is supplied again, the liquid crystal molecules are not well controlled and flicker (flicker) or the like occurs. In particular, in the horizontal electric field method, since the distance between the pixel electrode and the common electrode is shorter than in the vertical electric field method, a strong electric field acts on the alignment film and the liquid crystal layer, and this inconvenience is likely to be remarkable. It was.

  On the other hand, the liquid crystal alignment film is generally formed by printing a liquid crystal aligning agent, performing drying and baking, and then performing a rubbing process. However, in a horizontal electric field type liquid crystal cell, the liquid crystal alignment film is formed only on one side of the substrate. Since the substrate has an electrode structure, the substrate has large irregularities, and an insulator such as silicon nitride may be formed on the surface of the substrate, so that a liquid crystal alignment treatment agent superior in printability compared to conventional alignment agents can be obtained. It has been demanded. Furthermore, as compared with the conventional liquid crystal cell, there is a problem that peeling or rubbing due to the rubbing process is likely to occur, and these peeling and scratches deteriorate the display quality. Furthermore, in a system such as an IPS (In-Plane Switching) system in which liquid crystal molecules that are horizontally aligned with the substrate are driven by lateral electrolysis, the stability of the liquid crystal alignment is also important. If the alignment stability is low, the liquid crystal does not return to the initial state when the liquid crystal is driven for a long time, resulting in a decrease in contrast or burn-in.

Patent Document 1 discloses an amic acid unit derived from an aromatic tetracarboxylic acid as a liquid crystal aligning agent that is excellent in printability and rubbing resistance and has little afterimage and image sticking when used in such a lateral electric field drive liquid crystal element. And a liquid crystal aligning agent containing both amic acid units derived from alicyclic tetracarboxylic acid by copolymerization or mixing. Further, as a liquid crystal alignment agent for obtaining a liquid crystal alignment film having excellent liquid crystal alignment properties, alignment regulating power, rubbing resistance, high voltage holding ratio, and reduced charge accumulation, Patent Document 2 discloses a film alignment film. A liquid crystal aligning agent comprising: a low-resistance polyimide precursor having a volume resistivity of 1 × 10 ¹⁰ to 1 × 10 ¹⁴ Ωcm; and a highly-oriented polyimide precursor or polyimide having a specific structure; and A liquid crystal display element using this liquid crystal aligning agent is disclosed.

  However, with the improvement in performance of liquid crystal display elements, the characteristics required for the liquid crystal alignment film are becoming strict, and it is difficult to satisfy all the required characteristics only with the conventional technology.

International Publication WO02 / 33481 Pamphlet International Publication WO 2004/53583 Pamphlet

  SUMMARY OF THE INVENTION An object of the present invention is to obtain a liquid crystal alignment film that is less susceptible to peeling or rubbing due to rubbing treatment while maintaining the characteristics that have been conventionally required, particularly afterimage erasing time and stability of liquid crystal alignment.

  As a result of intensive studies to solve the above problems, the present inventors have used the above-described problems by using a plurality of diamine compounds having a specific structure and aliphatic tetracarboxylic dianhydrides having a specific structure. The present inventors have found that a liquid crystal alignment film exhibiting excellent characteristics satisfying the above requirements can be obtained. The present invention is based on this finding and has the following gist.

  A tetracarboxylic dianhydride component containing at least one tetracarboxylic dianhydride selected from the group consisting of an aromatic tetracarboxylic dianhydride and an aliphatic tetracarboxylic dianhydride, and a diamine having a tertiary nitrogen atom And a liquid crystal aligning agent containing at least one of a polyamic acid obtained by reacting a diamine component containing at least one diamine selected from the group consisting of diamines having the following structure and a polyimide obtained by imidizing the polyamic acid.

In the formula, R ₁ and R ₂ are each independently an alkylene group having 1 to 5 carbon atoms.

  Contains a polyamic acid obtained by reacting an aromatic tetracarboxylic dianhydride with a diamine component containing a diamine having the following structure, an aliphatic tetracarboxylic dianhydride, and a diamine having a tertiary nitrogen atom The liquid crystal aligning agent of 1 containing the polyamic acid obtained by making the diamine component to react react.

In the formula, R ₁ and R ₂ are each independently an alkylene group having 1 to 5 carbon atoms.

  The aliphatic tetracarboxylic dianhydride is 1,2,3,4-cyclobutanetetracarboxylic dianhydride and bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride. Selected from anhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,4,5-pentanetetracarboxylic dianhydride The liquid crystal aligning agent of 1 or 2 characterized by containing the said at least 1 sort (s) of tetracarboxylic dianhydride.

  3. The liquid crystal aligning agent according to any one of 1 to 3, wherein the tertiary nitrogen atom forms a heterocyclic ring in the diamine containing the tertiary nitrogen atom.

  The liquid crystal aligning agent according to any one of 1 to 4, wherein the diamine containing a tertiary nitrogen atom is represented by the following structure.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal aligning film which hardly raise | generates peeling and rubbing scraping by a rubbing process, and a liquid crystal display element using the same are provided, maintaining the afterimage erasing time and the stability of liquid crystal alignment.

  The present invention is described in detail below.

  The liquid crystal aligning agent of the present invention is a composition used for forming a liquid crystal aligning film, and is at least one tetracarboxylic acid selected from the group consisting of aromatic tetracarboxylic dianhydrides and aliphatic tetracarboxylic dianhydrides. A tetracarboxylic dianhydride component including an acid dianhydride, a diamine having a tertiary nitrogen atom (hereinafter also referred to as a first diamine) and a diamine having the following structure (hereinafter also referred to as a second diamine). It contains at least one of a polyamic acid obtained by reacting a diamine component containing at least one diamine selected from the group and a polyimide obtained by imidizing it.

In the formula, R ₁ and R ₂ are each independently an alkylene group having 1 to 5 carbon atoms.

  The liquid crystal aligning agent of the present invention comprises an aromatic tetracarboxylic dianhydride, an aliphatic tetracarboxylic dianhydride, a single polyamic acid obtained using the first diamine and the second diamine, and A polyimide obtained by imidization may be used, but a polyamic acid obtained by reacting an aromatic tetracarboxylic dianhydride and a diamine component containing a second diamine, and an aliphatic tetracarboxylic dianhydride and the first What mixed the polyamic acid obtained by making the diamine component containing these diamines react may be used.

<Aromatic tetracarboxylic dianhydride>
An aromatic tetracarboxylic dianhydride is used for the liquid crystal aligning agent of the present invention. These may be used alone or in combination of two or more. Examples of tetracarboxylic acids that are raw materials for obtaining aromatic tetracarboxylic dianhydrides include pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid. 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7-anthracenetetracarboxylic acid, 1,2,5,6-anthracenetetracarboxylic acid, 3,3 ′, 4,4′- Biphenyltetracarboxylic acid, 2,3,3 ′, 4-biphenyltetracarboxylic acid, bis (3,4-dicarboxyphenyl) ether, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, bis (3 4-dicarboxyphenyl) sulfone, bis (3,4-dicarboxyphenyl) methane, 2,2-bis (3,4-dicarboxyphenyl) propane, 1,1,1,3 , 3-hexafluoro-2,2′-bis (3,4-dicarboxyphenyl) propane, bis (3,4-dicarboxyphenyl) dimethylsilane, bis (3,4-dicarboxyphenyl) diphenylsilane, 2 , 3,4,5-pyridinetetracarboxylic acid, 2,6-bis (3,4-dicarboxyphenyl) pyridine, etc., from the viewpoint of reducing the orientation and afterimage characteristics of the liquid crystal, pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, bis (3,4-di Carboxyphenyl) ether and the like, and pyromellitic acid and 3,3 ′, 4,4′-biphenyltetracarboxylic acid are more preferable.

<Aliphatic tetracarboxylic dianhydride>
An aliphatic tetracarboxylic dianhydride is also used in the liquid crystal aligning agent of the present invention. These may be used alone or in combination of two or more. Examples of the tetracarboxylic acid that is a raw material for obtaining an aliphatic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cycloheptanetetracarboxylic acid, 3,4,5-tetrahydrofurantetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 1,2,4,5-pentanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3,4-dicarboxy-1-cyclohexylsuccinic acid, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic acid, bicyclo [3,3,0] octane-2,4 6,8-tetracarboxylic acid, 2,3,5-tricarboxycyclopentylacetic acid, 1,2,3,4-cycloheptanetetracarboxylic acid, 2,3,4,5-tetrahydro Lofuran tetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3,4-dicarboxy-1-cyclohexylsuccinic acid, 3,4-dicarboxy-1,2,3,4-tetrahydro-1 -Naphthalene succinic acid, bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic acid, 2,3,5-tricarboxycyclopentyl acetic acid, etc. 1,2,3,4-cyclobutanetetracarboxylic acid or derivatives thereof are preferred. Further, from the viewpoint of a low pretilt angle required for a liquid crystal display element for driving a horizontal electric field, bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic acid, 2,3,5-tricarboxylic acid is used. Carboxycyclopentyl acetic acid, 1,2,3,4-butanetetracarboxylic acid and 1,2,4,5-pentanetetracarboxylic acid are preferred.
Accordingly, dianhydrides of 1,2,3,4-cyclobutanetetracarboxylic acid or derivatives thereof and bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic acid, 2,3, When at least one tetracarboxylic dianhydride selected from 5-tricarboxycyclopentylacetic acid, butanetetracarboxylic acid, 1,2,4,5-pentanetetracarboxylic dianhydride is used in combination, good liquid crystal alignment And a low pretilt angle can be achieved.

<First diamine>
The 1st diamine used when synthesize | combining the polyamic acid used for the liquid crystal aligning agent of this invention is a diamine which has a tertiary nitrogen atom in a molecule | numerator. At that time, it is preferable that the tertiary nitrogen atom constitutes a nitrogen atom-containing heterocyclic ring. Examples of the heterocyclic structure containing a nitrogen atom include a pyrrole ring, a pyrrolidine ring, an imidazole ring, a pyridine ring, a piperidine ring, and a pyrimidine ring. It is particularly preferable to contain a piperidine ring.
Specific examples of the second diamine include the following compounds.

<Second diamine>
The 2nd diamine used when synthesize | combining the polyamic acid used for the liquid crystal aligning agent of this invention is represented by following formula (1).

In the formula, R ₁ and R ₂ are each independently an alkylene group having 1 to 5 carbon atoms. Among them, from the viewpoint of good liquid crystal orientation, R ₁ and R ₂ are preferably an alkylene group having 1 to 3 carbon atoms, and both R ₁ and R ₂ are alkylene groups having 2 carbon atoms. Most preferably.

<Other diamines>
In synthesizing the polyamic acid used in the liquid crystal aligning agent of the present invention, other diamine compounds can be used in addition to the first diamine and the second diamine as long as the effects of the present invention are not impaired. . Specific examples of other diamine compounds are listed below. p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2, 5-diaminotoluene, 2,6-diaminotoluene, 2,5-diaminophenol, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4 , 6-diaminoresorcinol, 4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-dihydroxy -4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 3,3'-trif Fluoromethyl-4,4′-diaminobiphenyl, 3,4′-diaminobiphenyl, 3,3′-diaminobiphenyl, 2,2′-diaminobiphenyl, 2,3′-diaminobiphenyl, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 2,2′-diaminodiphenylmethane, 2,3′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 3, 4'-diaminodiphenyl ether, 2,2'-diaminodiphenyl ether, 2,3'-diaminodiphenyl ether, 4,4'-sulfonyldianiline, 3,3'-sulfonyldianiline, bis (4-aminophenyl) silane, bis (3-aminophenyl) silane, dimethyl-bis (4-a Nophenyl) silane, dimethyl-bis (3-aminophenyl) silane, 4,4′-thiodianiline, 3,3′-thiodianiline, 4,4′-diaminodiphenylamine, 3,3′-diaminodiphenylamine, 3,4′- Diaminodiphenylamine, 2,2'-diaminodiphenylamine, 2,3'-diaminodiphenylamine, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 1,4-diaminonaphthalene, 2,2′-diaminobenzophenone, 2,3′-diaminobenzophenone, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 1,8-diaminonaphthalene, 2,5-diaminonaphthalene 2,6-diaminonaphthalene, 2,7-diaminonaphth Talene, 2,8-diaminonaphthalene, 1,2-bis (4-aminophenyl) ethane, 1,2-bis (3-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1, 3-bis (3-aminophenyl) propane, 1,4-bis (4-aminophenyl) butane, 1,4-bis (3-aminophenyl) butane, bis (3,5-diethyl-4-aminophenyl) Methane, 1,4-bis (4-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,4-bis (4-aminobenzyl) benzene, 1,3-bis (4-amino) Phenethyl) urea, N-methyl-2- (4-aminophenyl) ethylamine, 4,4 ′-[1,4-phenylenebis (methylene)] dianiline, 4,4 ′-[1,3-phenylenebis (meth) )] Dianiline, 3,4 ′-[1,4-phenylenebis (methylene)] dianiline, 3,4 ′-[1,3-phenylenebis (methylene)] dianiline, 3,3 ′-[1,4 -Phenylenebis (methylene)] dianiline, 3,3 ′-[1,3-phenylenebis (methylene)] dianiline, 1,4-phenylenebis [(4-aminophenyl) methanone], 1,4-phenylenebis [ (3-aminophenyl) methanone], 1,3-phenylenebis [(4-aminophenyl) methanone], 1,3-phenylenebis [(3-aminophenyl) methanone], 1,4-phenylenebis (4- Aminobenzoate), 1,4-phenylenebis (3-aminobenzoate), 1,3-phenylenebis (4-aminobenzoate), 1,3-phenylenebis (3-a Nobenzoate), bis (4-aminophenyl) terephthalate, bis (3-aminophenyl) terephthalate, bis (4-aminophenyl) isophthalate, bis (3-aminophenyl) isophthalate, N, N ′-(1, 4-phenylene) bis (4-aminobenzamide), N, N ′-(1,3-phenylene) bis (4-aminobenzamide), N, N ′-(1,4-phenylene) bis (3-aminobenzamide) ), N, N ′-(1,3-phenylene) bis (3-aminobenzamide), N, N′-bis (4-aminophenyl) terephthalamide, N, N′-bis (3-aminophenyl) terephthalate Amides, N, N′-bis (4-aminophenyl) isophthalamide, N, N′-bis (3-aminophenyl) isophthalamide, 9,10-bis (4 Aminophenyl) anthracene, 4,4′-bis (4-aminophenoxy) diphenylsulfone, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, 2,2′-bis [4- (4 -Aminophenoxy) phenyl] hexafluoropropane, 2,2'-bis (4-aminophenyl) hexafluoropropane, 2,2'-bis (3-aminophenyl) hexafluoropropane, 2,2'-bis (3 -Amino-4-methylphenyl) hexafluoropropane, 2,2'-bis (4-aminophenyl) propane, 2,2'-bis (3-aminophenyl) propane, 2,2'-bis (3-amino) -4-methylphenyl) propane, 1,3-bis (3-aminophenoxy) propane, 1,4-bis (3-aminophenoxy) butane, 1,5-bis ( -Aminophenoxy) pentane, 1,6-bis (3-aminophenoxy) hexane, 1,7- (3-aminophenoxy) heptane, 1,8-bis (3-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,9-bis (3-aminophenoxy) nonane, 1,10- (4-aminophenoxy) decane, 1,10- (3-aminophenoxy) decane, 1,11- ( 4-aminophenoxy) undecane, 1,11- (3-aminophenoxy) undecane, 1,12- (4-aminophenoxy) dodecane, 1,12- (3-aminophenoxy) dodecane, bis (4-aminocyclohexyl) Methane, bis (4-amino-3-methylcyclohexyl) methane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5- Diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diamino Examples include dodecane. Of these, 4,4′-diaminodiphenylmethane, 1,3-bis (4-aminophenethyl) urea, and N-methyl-2- (4-aminophenyl) ethylamine are preferably used from the viewpoint of good orientation and the like. .

  The other diamine compounds mentioned above are of one type depending on characteristics such as volume resistivity, rubbing resistance, ion density characteristics, transmittance, liquid crystal alignment characteristics, voltage holding characteristics and accumulated charges when used as a liquid crystal alignment film. Alternatively, two or more types can be mixed and used.

<Synthesis of polyamic acid>
When the polyamic acid used in the liquid crystal aligning agent of the present invention is obtained by reaction of tetracarboxylic dianhydride and diamine, a method of mixing tetracarboxylic dianhydride and diamine in an organic solvent and reacting them is Convenient.

  The organic solvent used in the above reaction is not particularly limited as long as the generated polyamic acid dissolves. Specific examples are N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethyl. Examples thereof include 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. 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.

  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, In this invention, any of these methods may be sufficient. Further, 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 reacted in a mixed state in advance or may be reacted individually and sequentially.

  The temperature at the time of making a tetracarboxylic dianhydride component and a diamine component react in an organic solvent is 0-150 degreeC normally, Preferably it is 5-100 degreeC, More preferably, it is 10-80 degreeC. 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 reaction can be carried out at any concentration, but if the concentration is too low, it is difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring is difficult. Therefore, it is preferably 1 to 50% by weight, more preferably 5 to 30% by weight. The initial reaction may be carried out at a high concentration, and then an organic solvent may be added.

  The ratio of the tetracarboxylic dianhydride component: diamine component used in the polyamic acid polymerization reaction is preferably 1: 0.8 to 1.2 in terms of molar ratio. Moreover, since the polyamic acid obtained by making an excessive diamine component may increase the coloring of a solution, when the coloring of a solution is worrisome, said ratio should just be 1: 0.8-1. . Similar to the normal polycondensation reaction, the closer the molar ratio is to 1: 1, the higher the molecular weight of the polyamic acid obtained. If the molecular weight of the polyamic acid is too small, the strength of the coating film obtained therefrom may be insufficient. Conversely, if the molecular weight of the polyamic acid is too large, the solution viscosity when the liquid crystal aligning agent is used as the coating solution is low. It may become too high, and the workability at the time of coating film formation and the uniformity of a coating film may worsen.

  The weight average molecular weight of such a polyamic acid is preferably 5,000 to 300,000, more preferably 10,000 to 200,000, and the number average molecular weight is preferably 2,500 to 300,000. It is 150,000, More preferably, it is 5,000-100,000.

  If you do not want to include the solvent used for the polymerization of the polyamic acid in the liquid crystal aligning agent of the present invention, or if there are unreacted monomer components or impurities in the reaction solution and you want to remove them, the polyamic acid Perform precipitation recovery and purification. As the method, a method of adding the polyamic acid solution to a stirring poor solvent and recovering the precipitate is simple. Although it does not specifically limit as a poor solvent used for precipitation collection | recovery of polyamic acid, Methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene etc. can be illustrated. The polyamic acid precipitated by introducing it into a poor solvent can be recovered by filtration, washing and drying at room temperature or under reduced pressure at normal temperature or under reduced pressure. If this powder is further dissolved in a good solvent and reprecipitation is repeated 2 to 10 times, the polyamic acid can be purified. When the impurities cannot be removed by a single precipitation recovery operation, it is preferable to perform this purification step. In this case, it is preferable to use three or more kinds of poor solvents such as alcohols, ketones, and hydrocarbons as the poor solvent because the purification efficiency is further increased. The precipitation recovery and purification operations described above can be performed in the same manner when synthesizing polyamic acid alkyl ester and polyimide described later.

  When the polyamic acid is partially or wholly imidized, the production method is not particularly limited, but the polyamic acid obtained by reacting tetracarboxylic dianhydride and diamine may be imidized as it is in a solution. it can. At this time, in order to convert a part or all of the polyamic acid into polyimide, a method of dehydrating and ring-closing by heating or a method of chemically ring-closing using a known dehydration and ring-closing catalyst is employed. In the method by heating, an arbitrary temperature of 100 ° C. to 300 ° C., preferably 120 ° C. to 250 ° C. can be selected. In the method of chemically ring-closing, for example, pyridine, triethylamine and the like can be used in the presence of acetic anhydride and the like, and the temperature at this time can be selected from -20 ° C to 200 ° C.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of this invention is a coating liquid for forming a liquid crystal aligning film, and is a solution which the resin component for forming a resin film melt | dissolved in the organic solvent. Here, the said resin component is a resin component containing at least 1 sort (s) among the above-mentioned polyamic acid and the polyimide obtained by imidating this. In that case, the content of the resin component is preferably 1% by mass to 20% by mass, more preferably 3% by mass to 15% by mass, and particularly preferably 3% by mass to 10% by mass.

  In the liquid crystal aligning agent of the present invention, all of the resin components may be the polyamic acid of the present invention and a polyimide obtained by imidizing it, or other polymers may be mixed. . At that time, the content of the polymer other than the polyamic acid of the present invention and the polyimide obtained by imidizing it in the resin component is 0.5% by mass to 15% by mass, preferably 1% by mass to 10% by mass. It is.

  Examples of such other polymers include polyamic acid of the present invention and polyamic acid other than polyimide obtained by imidizing it, and polyimide obtained by imidizing it.

  The liquid crystal aligning agent of the present invention is a polyamic acid obtained by reacting an aromatic tetracarboxylic dianhydride and a diamine component containing a second diamine, and an aliphatic tetracarboxylic dianhydride and a first diamine. When the polyamic acid obtained by reacting with a diamine component containing is mixed, the mixing ratio is a diamine containing an aromatic tetracarboxylic dianhydride and a second diamine in mass ratio. The polyamic acid obtained by reacting the components with the polyamic acid: aliphatic tetracarboxylic dianhydride and the diamine component containing the first diamine is preferably 50:50 to 10:90.

  The organic solvent used for the liquid crystal aligning agent of this invention will not be specifically limited if it is an organic solvent in which a resin component is dissolved. Specific examples are given below.

  N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethylsulfoxide, tetramethylurea, pyridine, Dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, 4 -Hydroxy-4-methyl-2-pentanone and the like. These may be used alone or in combination.

  The liquid crystal aligning agent of this invention may contain components other than the above. Examples thereof include solvents and compounds that improve the film thickness uniformity and surface smoothness when a liquid crystal aligning agent is applied, and compounds that improve the adhesion between the liquid crystal aligning film and the substrate.

  Specific examples of the solvent (poor solvent) that improves the uniformity of the film thickness and the surface smoothness include the following.

  For example, isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoacetate Isopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipro Lenglycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3 -Methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl Ether, 1-hexanol, n-hexane, n-pentane, n-octane Diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, Ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1 -Butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol- Low 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 isoamyl ester Examples include solvents having surface tension.

  These poor solvents may be used alone or in combination. When using the above solvent, it is preferable that it is 5 to 80 mass% of the whole solvent contained in a liquid crystal aligning agent, More preferably, it is 20 to 60 mass%.

  Examples of compounds that improve film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants.

  More specifically, for example, F-top EF301, EF303, EF352 (manufactured by Tochem Products), MegaFuck F171, F173, R-30 (manufactured by Dainippon Ink), Florard FC430, FC431 (manufactured by Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (Asahi Glass Co., Ltd.) and the like. The use ratio of these surfactants is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the resin component contained in the liquid crystal aligning agent.

  Specific examples of the compound that improves the adhesion between the liquid crystal alignment film and the substrate include the following functional silane-containing compounds and epoxy group-containing compounds.

  For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-tri Toxisilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxy Silane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyl Trimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, poly Lopylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl -2,4-hexanediol, N, N, N ′, N ′,-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′ , N ′,-tetraglycidyl-4,4′-diaminodiphenylmethane and the like.

  When using a compound that improves adhesion to the substrate, the amount used is preferably 0.1 to 30 parts by mass, more preferably 100 parts by mass of the resin component contained in the liquid crystal aligning agent. Is 1 to 20 parts by mass. If the amount used is less than 0.1 parts by mass, the effect of improving the adhesion cannot be expected, and if it exceeds 30 parts by mass, the orientation of the liquid crystal may deteriorate.

  In addition to the above, the liquid crystal aligning agent of the present invention has a dielectric or conductive material for the purpose of changing the electrical properties such as the dielectric constant and conductivity of the liquid crystal aligning film, as long as the effects of the present invention are not impaired. Further, a crosslinkable compound for the purpose of increasing the hardness and density of the liquid crystal alignment film may be added.

  The liquid crystal aligning agent of the present invention obtained as described above can be filtered as necessary, applied to a substrate, dried and baked to form a coating film. By performing alignment treatment such as irradiation, it can be used as a liquid crystal alignment film.

  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 reflection type liquid crystal display element, an opaque material such as a silicon wafer can be used as long as the substrate is only on one side, and in this case, a material that reflects light such as aluminum can be used.

  Examples of the method for applying the liquid crystal aligning agent include spin coating, printing, and ink-jet methods, but from the viewpoint of productivity, the transfer printing method is widely used industrially. 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 a liquid crystal aligning agent can be performed at 100-350 degreeC arbitrary temperatures, Preferably it is 150 to 300 degreeC, More preferably, it is 200 to 250 degreeC. When the liquid crystal aligning agent contains a polyimide precursor, the conversion rate from the polyimide precursor to the polyimide varies depending on the baking 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 that it is 5 to 300 nm, preferably 10 to 100 nm. It is.

<Liquid crystal display element>
The liquid crystal display element of the present invention is a liquid crystal display element obtained by obtaining a substrate with a liquid crystal alignment film from the liquid crystal aligning agent of the present invention by the method described above, and then preparing a liquid crystal cell by a known method. If an example of liquid crystal cell production is given, a pair of substrates on which a liquid crystal alignment film is formed are usually 1 to 30 μm, preferably 2 to 10 μm, and a rubbing direction is preferably 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. An existing rubbing apparatus can be used for the rubbing treatment for the liquid crystal alignment film. Examples of the material of the rubbing cloth at this time include cotton, rayon, and nylon. 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.

  Thus, since the liquid crystal display element produced using the liquid crystal aligning agent of this invention is excellent in the orientation of a liquid crystal, alignment control power, and has the outstanding electrical property, it is a contrast fall or image sticking. A liquid crystal display device that is unlikely to occur can be obtained. Among these liquid crystal display elements, the liquid crystal display element is particularly preferably used for a horizontal electric field type liquid crystal display element in which seizure due to the alignment regulating force easily occurs.

  The details of the production method of the present invention will be described below with reference to experimental methods and results obtained by examining the composition and blending ratio of raw materials, and examples that are typical production methods. The present invention is not limited to these examples.

Explanation of abbreviations used in this example (tetracarboxylic dianhydride)
The following CA-1 to CA-7 tetracarboxylic dianhydrides

(Diamine)
The following diamine compounds of DA-1 and DA-2

(Organic solvent)
NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve

(Additive)
LS-3150: 3-aminopropyltriethoxysilane

Each measurement method is shown below.
<Rubbing resistance evaluation>
The obtained liquid crystal aligning agent is filtered through a 1.0 μm filter, spin-coated on a glass substrate with a transparent electrode, dried on an 80 ° C. hot plate for 5 minutes, and then baked at 230 ° C. for 20 minutes. A polyimide film having a thickness of 100 nm was obtained. This polyimide film was rubbed with a rayon cloth (roll diameter 120 mm, rotation speed 1000 rpm, moving speed 20 mm / sec, pushing amount 0.2 mm). The surface of the film was observed using a confocal laser microscope, and was scraped at a magnification of 100 times to observe the presence of scraps and the presence of scratches. The case where no scraped scraps or scratches were observed was evaluated as “◯”, the case where several scraped scraps or several rubbing scratches were observed was evaluated as “△”, and the case where many scraped scraps or rubbing scratches were observed was evaluated as “X”.

<Production of liquid crystal display element>
First, a substrate with electrodes was prepared. The substrate is a glass substrate having a size of 30 mm × 35 mm and a thickness of 0.7 mm. On the substrate, an IZO electrode having a solid pattern constituting a counter electrode as a first layer is formed. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by the CVD method is formed as the second layer. The second layer SiN film has a thickness of 500 nm and functions as an interlayer insulating film. On the second SiN film, a comb-like pixel electrode formed by patterning an IZO film as the third layer is arranged to form two pixels, a first pixel and a second pixel. ing. The size of each pixel is 10 mm long and about 5 mm wide. At this time, the first-layer counter electrode and the third-layer pixel electrode are electrically insulated by the action of the second-layer SiN film.

  The pixel electrode of the third layer has a comb-like shape configured by arranging a plurality of dog-shaped electrode elements whose central portion is bent. The width in the short direction of each electrode element is 3 μm, and the distance between the electrode elements is 6 μm. Since the pixel electrode forming each pixel is formed by arranging a plurality of bent-shaped electrode elements in the central portion, the shape of each pixel is not rectangular, but in the central portion like the electrode elements. It has a shape that bends and resembles a bold-faced koji. Each pixel is divided into upper and lower portions with a central bent portion as a boundary, and has a first region on the upper side of the bent portion and a second region on the lower side.

  When the first region and the second region of each pixel are compared, the formation directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode element of the pixel electrode is formed to form an angle of + 10 ° (clockwise) in the first region of the pixel, and the pixel in the second region of the pixel. The electrode element of the electrode is formed so as to form an angle of −10 ° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotation operation (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode are mutually in the substrate plane. It is comprised so that it may become a reverse direction.

  Next, after the obtained liquid crystal aligning agent is filtered through a 1.0 μm filter, an ITO film is formed on the back surface as the prepared substrate with electrodes and a counter substrate, and a columnar spacer having a height of 4 μm. Each of the glass substrates having was spin-coated. Subsequently, after drying for 5 minutes on a 50 degreeC hotplate, it baked at 230 degreeC for 30 minutes, and obtained the polyimide film on each board | substrate as a 60 nm-thick coating film. This polyimide film is rubbed with a rayon cloth in a predetermined rubbing direction (roll diameter 120 mm, rotation speed 500 rpm, moving speed 30 mm / sec, pushing amount 0.3 mm), and then irradiated with ultrasonic waves for 1 minute in pure water. And dried at 80 ° C. for 10 minutes.

  Then, using the two types of substrates with the liquid crystal alignment film, the rubbing directions are combined so that they are antiparallel, the periphery is sealed leaving the liquid crystal injection port, and an empty cell with a cell gap of 3.8 μm is formed. Produced. After liquid crystal (MLC-2041, manufactured by Merck & Co., Inc.) was vacuum-injected into the empty cell at room temperature, the injection port was sealed to obtain an anti-parallel alignment liquid crystal cell. The obtained liquid crystal cell constitutes an IPS mode liquid crystal display element. Thereafter, the obtained liquid crystal cell was heated at 110 ° C. for 1 hour and allowed to stand overnight before being used for each evaluation.

<Afterimage evaluation>
The afterimage was evaluated using the following optical system and the like.

  The prepared liquid crystal cell is installed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the LED backlight is turned on with no voltage applied, so that the brightness of transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted.

  Next, a VT curve (voltage-transmittance curve) was measured while applying an AC voltage with a frequency of 30 Hz to the liquid crystal cell, and an AC voltage with a relative transmittance of 23% was calculated as a drive voltage.

  In the afterimage evaluation, a DC voltage of 1 V was applied at the same time while driving the liquid crystal cell by applying an AC voltage of 30 Hz with a relative transmittance of 23%, and the liquid crystal cell was driven for 60 minutes. Thereafter, the applied DC voltage value was set to 0V, and only the application of the DC voltage was stopped, and the driving was continued for 30 minutes in that state.

  The afterimage evaluation was defined as “good” when the relative transmittance decreased to 25% or less by the time 60 minutes elapsed from the start of application of the DC voltage. When it took 60 minutes or more for the relative transmittance to drop to 25% or less, it was defined as “bad” and evaluated.

  And the afterimage evaluation according to the method mentioned above was performed on the temperature conditions of the state whose temperature of a liquid crystal cell is 23 degreeC. The evaluation results are shown in Table 3.

<Afterimage evaluation by long-term driving>
Using this liquid crystal cell, an AC voltage of 10 VPP was applied for 100 hours at a frequency of 30 Hz in a constant temperature environment of 60 ° C. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left as it was at room temperature for one day.

  After leaving, the liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal, and the backlight is turned on with no voltage applied so that the brightness of transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the first pixel became darkest to the angle at which the first region became darkest was calculated as an angle Δ. Similarly, for the second pixel, the second area was compared with the first area, and a similar angle Δ was calculated. Then, the average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal cell. When the value of the angle Δ of the liquid crystal cell exceeded 0.2 degrees, it was defined as “defective” and evaluated. When the value of the angle Δ of the liquid crystal cell did not exceed 0.2 degrees, it was defined as “good” and evaluated.

<Synthesis of polymer>
<Synthesis Example 1>
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 7.64 g (26.5 mmol) of DA-1, 10.4 g (26.5 mmol) of DA-2 and 100 g of N-methyl-2-pyrrolidone were added. In addition, the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 5.78 g (26.5 mmol) of CA-1 and 3.98 g (15.9 mmol) of CA-3 were added, and the mixture was stirred at 50 ° C. for 3 hours. Thereafter, the temperature of the reaction solution was lowered to 23 ° C., 1.66 g (8.48 mmol) of CA-2 and N-methyl-2-pyrrolidone were added so that the solid concentration was 15% by mass, and the mixture was stirred at 23 ° C. for 20 hours. By stirring, a polyamic acid solution (abbreviated as P1) was obtained. It was 481 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P1) solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).

  To 100 g of this polyamic acid (P1) solution, 87.4 g of N-methyl-2-pyrrolidone, 0.075 g of LS-3150 and 50 g of butyl cellosolve were added, and a liquid crystal aligning agent (Q1) having a P1 concentration of 5.97% by mass Got.

<Synthesis Example 2>
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 7.79 g (27.0 mmol) of DA-1, 10.6 g (27.0 mmol) of DA-2 and 100 g of N-methyl-2-pyrrolidone were added. In addition, the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 5.89 g (27.0 mmol) of CA-1 and 3.21 g (16.2 mmol) of CA-4 were added, and the mixture was stirred at 50 ° C. for 3 hours. Thereafter, the temperature of the reaction solution was lowered to 23 ° C., 1.70 g (8.64 mmol) of CA-2 and N-methyl-2-pyrrolidone were added so that the solid concentration was 15% by mass, and the mixture was stirred at 23 ° C. for 20 hours. By stirring, a solution of polyamic acid (abbreviated as P2) was obtained. It was 512 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P2) solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).

  To 100 g of this polyamic acid (P2) solution, 87.4 g of N-methyl-2-pyrrolidone, 0.075 g of LS-3150 and 50 g of butyl cellosolve were added, and a liquid crystal aligning agent (Q2) having a P2 concentration of 5.86% by mass Got.

<Synthesis Example 3>
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 7.79 g (27.0 mmol) of DA-1, 10.6 g (27.0 mmol) of DA-2 and 100 g of N-methyl-2-pyrrolidone were added. In addition, the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 5.89 g (27.0 mmol) of CA-1 and 3.44 g (16.2 mmol) of CA-4 were added, and the mixture was stirred at 50 ° C. for 3 hours. Thereafter, the temperature of the reaction solution was lowered to 23 ° C., 1.70 g (8.64 mmol) of CA-2 and N-methyl-2-pyrrolidone were added so that the solid concentration was 15% by mass, and the mixture was stirred at 23 ° C. for 20 hours. By stirring, a solution of polyamic acid (abbreviated as P3) was obtained. It was 492 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P3) solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).

  To 100 g of this polyamic acid (P3) solution, 87.4 g of N-methyl-2-pyrrolidone, 0.075 g of LS-3150 and 50 g of butyl cellosolve were added, and a liquid crystal aligning agent (Q3) having a P3 concentration of 5.96% by mass Got.

<Synthesis Example 4>
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 7.79 g (27.0 mmol) of DA-1, 10.6 g (27.0 mmol) of DA-2 and 100 g of N-methyl-2-pyrrolidone were added. In addition, the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 5.89 g (27.0 mmol) of CA-1 and 3.63 g (16.2 mmol) of CA-6 were added, and the mixture was stirred at 50 ° C. for 3 hours. Thereafter, the temperature of the reaction solution was lowered to 23 ° C., 1.70 g (8.64 mmol) of CA-2 and N-methyl-2-pyrrolidone were added so that the solid concentration was 15% by mass, and the mixture was stirred at 23 ° C. for 20 hours. By stirring, a solution of polyamic acid (abbreviated as P4) was obtained. It was 479 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P4) solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).

  To 100 g of this polyamic acid (P4) solution, 87.4 g of N-methyl-2-pyrrolidone, 0.075 g of LS-3150 and 50 g of butyl cellosolve were added, and a liquid crystal aligning agent (Q4) having a P4 concentration of 5.99% by mass Got.

<Synthesis Example 5>
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 7.35 g (25.5 mmol) of DA-1, 10.01 g (25.5 mmol) of DA-2, and 100 g of N-methyl-2-pyrrolidone were added. In addition, the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 7.50 g (25.5 mmol) of CA-7 and 3.83 g (15.3 mmol) of CA-3 were added, and the mixture was stirred at 50 ° C. for 3 hours. Thereafter, the temperature of the reaction solution was lowered to 23 ° C., 1.60 g (8.16 mmol) of CA-2 and N-methyl-2-pyrrolidone were added so that the solid concentration was 15% by mass, and the mixture was stirred at 23 ° C. for 20 hours. By stirring, a polyamic acid solution (abbreviated as P5) was obtained. It was 465 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P5) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).

  To 100 g of this polyamic acid (P5) solution, 87.4 g of N-methyl-2-pyrrolidone, 0.075 g of LS-3150 and 50 g of butyl cellosolve were added, and a liquid crystal aligning agent (Q5) having a P5 concentration of 5.88% by mass. Got.

<Synthesis Example 6>
DA-1 (13.55 g, 47.0 mmol) and N-methyl-2-pyrrolidone (100 g) were added to a 200 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, and stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 9.74 g (44.7 mmol) of CA-1 and N-methyl-2-pyrrolidone were added so that the solid concentration was 12% by mass, and the mixture was stirred at 50 ° C. for 24 hours. Thereafter, the temperature of the reaction solution was lowered to 23 ° C. to obtain a polyamic acid solution (abbreviated as P6). It was 318 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P6) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).

  60 g of N-methyl-2-pyrrolidone, 40 g of LS-3150 and butyl cellosolve were added to 100 g of this polyamic acid (P6) solution to obtain a liquid crystal aligning agent (Q6) having a P6 concentration of 5.94% by mass.

<Synthesis Example 7>
DA-2 (13.35 g, 34.0 mmol) and N-methyl-2-pyrrolidone (100 g) were added to a 200 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.33 g (11.9 mmol) of CA-2 was added and stirred at 23 ° C. for 5 hours. Thereafter, 3.37 g (17.0 mmol) of CA-4 was added, and the mixture was further stirred at 23 ° C. for 5 hours. Thereafter, 0.85 g (4.34 mmol) of CA-2 and N-methyl-2-pyrrolidone were added so that the solid concentration was 10% by mass, and the mixture was further stirred for 3 hours at 23 ° C. A solution (abbreviated as P7) was obtained. It was 1045 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P7) solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).

  To 100 g of this polyamic acid (P7) solution was added 33.55 g of N-methyl-2-pyrrolidone, 0.1 g of LS-3150 and 33.02 g of butyl cellosolve, and a liquid crystal aligning agent (P7 concentration of 5.91% by mass) Q7) was obtained.

<Synthesis Example 8>
20.0 g of liquid crystal aligning agent (Q6) and 80 g of liquid crystal aligning agent (Q7) were mixed and stirred at 23 ° C. for 20 hours to obtain a liquid crystal aligning agent (Q8).

<Synthesis Example 9>
DA-2 (12.56 g, 32.0 mmol) and N-methyl-2-pyrrolidone (100 g) were added to a 200 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.20 g (11.2 mmol) of CA-2 was added and stirred at 23 ° C. for 5 hours. Thereafter, 4.00 g (16.0 mmol) of CA-4 was added, and the mixture was further stirred at 23 ° C. for 5 hours. Thereafter, 0.89 g (4.56 mmol) of CA-2 and N-methyl-2-pyrrolidone were added so that the solid content concentration was 10% by mass, and the mixture was further stirred for 3 hours at 23 ° C. A solution (abbreviated as P8) was obtained. It was 981 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P8) solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).

  To 100 g of this polyamic acid (P8) solution, 33.55 g of N-methyl-2-pyrrolidone, 0.1 g of LS-3150 and 33.02 g of butyl cellosolve were added, and a liquid crystal aligning agent having a P8 concentration of 5.87% by mass ( Q9) was obtained.

<Synthesis Example 10>
20.0 g of liquid crystal aligning agent (Q6) and 80 g of liquid crystal aligning agent (Q9) were mixed and stirred at 23 ° C. for 20 hours to obtain a liquid crystal aligning agent (Q10).

<Synthesis Example 11>
DA-2 (12.56 g, 32.0 mmol) and N-methyl-2-pyrrolidone (100 g) were added to a 200 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.33 g (11.9 mmol) of CA-2 was added and stirred at 23 ° C. for 5 hours. Thereafter, 3.61 g (17.0 mmol) of CA-5 was added, and the mixture was further stirred at 23 ° C. for 5 hours. Thereafter, 0.96 g (4.90 mol) of CA-2 and N-methyl-2-pyrrolidone were added so that the solid content concentration was 10% by mass, and the mixture was further stirred for 3 hours at 23 ° C. A solution (abbreviated as P9) was obtained. It was 1005 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P9) solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).

  To 100 g of this polyamic acid (P9) solution, 33.55 g of N-methyl-2-pyrrolidone, 0.1 g of LS-3150 and 33.02 g of butyl cellosolve were added, and a liquid crystal aligning agent having a P9 concentration of 5.97% by mass ( Q11) was obtained.

<Synthesis Example 12>
20.0 g of liquid crystal aligning agent (Q6) and 80 g of liquid crystal aligning agent (Q11) were mixed and stirred at 23 ° C. for 20 hours to obtain a liquid crystal aligning agent (Q12).

<Synthesis Example 13>
DA-2 (12.96 g, 34.0 mmol) and N-methyl-2-pyrrolidone (100 g) were added to a 200 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.27 g (11.9 mmol) of CA-2 was added and stirred at 23 ° C. for 5 hours. Thereafter, 3.70 g (17.0 mmol) of CA-6 was added, and the mixture was further stirred at 23 ° C. for 5 hours. Thereafter, 0.92 g (4.85 mmol) of CA-2 and N-methyl-2-pyrrolidone were added so that the solid concentration would be 10% by mass, and the mixture was further stirred for 3 hours at 23 ° C. A solution (abbreviated as P10) was obtained. It was 977 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P10) solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).

  To 100 g of this polyamic acid (P10) solution, 33.55 g of N-methyl-2-pyrrolidone, 0.1 g of LS-3150 and 33.02 g of butyl cellosolve were added, and a liquid crystal aligning agent having a P10 concentration of 5.95% by mass ( Q13) was obtained.

<Synthesis Example 14>
20.0 g of the liquid crystal aligning agent (Q6) and 80 g of the liquid crystal aligning agent (Q13) were mixed and stirred at 23 ° C. for 20 hours to obtain a liquid crystal aligning agent (Q14).

<Comparative Synthesis Example 1>
17.58 g (61.0 mmol) of DA-1 and 100 g of N-methyl-2-pyrrolidone were added to a 200 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, and stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 6.65 g (30.5 mmol) of CA-1 and 5.38 g (27.5 mmol) of CA-2 were added so that the solid concentration was 15% by mass. Pyrrolidone was added and stirred at 23 ° C. for 5 hours to obtain a polyamic acid solution (abbreviated as P11). It was 1028 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P11) solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).

  100 g of N-methyl-2-pyrrolidone, 50 g of LS-3150 and butyl cellosolve were added to 100 g of this polyamic acid (P11) solution to obtain a liquid crystal aligning agent (Q15) having a P11 concentration of 5.91% by mass.

<Comparative Synthesis Example 2>
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, DA-1 (6.20 g, 21.5 mmol), DA-2 (8.44 g, 21.5 mmol) and N-methyl-2-pyrrolidone (100 g) were added. In addition, the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, N-methyl-2-pyrrolidone was added thereto such that CA-1 was 8.91 g (40.9 mmol) and the solid content concentration was 12% by mass, and the mixture was stirred at 50 ° C. for 24 hours. Thereafter, the temperature of the reaction solution was lowered to 23 ° C. to obtain a polyamic acid solution (abbreviated as P12). It was 351 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P12) solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).

  60 g of N-methyl-2-pyrrolidone, 40 g of LS-3150 and butyl cellosolve were added to 100 g of this polyamic acid (P12) solution to obtain a liquid crystal aligning agent (Q16) having a P12 concentration of 5.9% by mass.

<Comparative Synthesis Example 3>
To a 200 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 20.02 g (40.8 mmol) of DA-2 and 100 g of N-methyl-2-pyrrolidone were added, and stirred and dissolved while feeding nitrogen. While stirring the diamine solution, N-methyl-2-butanol was added so that 2.21 g (10.2 mmol) of CA-1 and 7.68 g (39.2 mmol) of CA-2 and a solid concentration of 15% by mass were obtained. Pyrrolidone was added and stirred at 23 ° C. for 5 hours to obtain a polyamic acid solution (abbreviated as P13). It was 825 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P13) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).

  100 g of N-methyl-2-pyrrolidone, 50 g of LS-3150 and butyl cellosolve were added to 100 g of this polyamic acid (P13) solution to obtain a liquid crystal aligning agent (Q17) having a P13 concentration of 5.85% by mass.

<Examples 1-9>
Using the liquid crystal aligning agents obtained in Synthesis Examples 1 to 5, 8, 10, 12, and 14, rubbing resistance evaluation, afterimage evaluation, and afterimage evaluation by long-term driving were performed. The results are shown in Table 1.

<Comparative Examples 1-3>
Using the liquid crystal aligning agents obtained in Comparative Synthesis Examples 1 to 3, rubbing resistance evaluation, afterimage evaluation, and afterimage evaluation by long-term driving were performed. The results are shown in Table 1.

  As described above, the liquid crystal aligning agent of the present invention showed good results in any of rubbing resistance, afterimage evaluation, and afterimage evaluation by long-term driving, but the liquid crystal aligning agents prepared in Comparative Examples 1 to 3 were Poor results were obtained for any of the evaluation items.

Claims (7)

A tetracarboxylic dianhydride component containing at least one tetracarboxylic dianhydride selected from the group consisting of an aromatic tetracarboxylic dianhydride and an aliphatic tetracarboxylic dianhydride, and a diamine having a tertiary nitrogen atom And a liquid crystal aligning agent containing at least one of a polyamic acid obtained by reacting a diamine component containing at least one diamine selected from the group consisting of diamines having the following structure and a polyimide obtained by imidizing the polyamic acid.

In the formula, R ₁ and R ₂ are each independently an alkylene group having 1 to 5 carbon atoms. Contains a polyamic acid obtained by reacting an aromatic tetracarboxylic dianhydride with a diamine component containing a diamine having the following structure, an aliphatic tetracarboxylic dianhydride, and a diamine having a tertiary nitrogen atom The liquid crystal aligning agent of Claim 1 containing the polyamic acid obtained by making the diamine component to react react.

In the formula, R ₁ and R ₂ are each independently an alkylene group having 1 to 5 carbon atoms. The aliphatic tetracarboxylic dianhydride is 1,2,3,4-cyclobutanetetracarboxylic dianhydride and bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride. Selected from anhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,4,5-pentanetetracarboxylic dianhydride The liquid crystal aligning agent according to claim 1, comprising at least one tetracarboxylic dianhydride. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein the tertiary nitrogen atom forms a heterocyclic ring in the diamine containing the tertiary nitrogen atom. The liquid crystal aligning agent according to any one of claims 1 to 4, wherein the diamine containing a tertiary nitrogen atom is represented by the following structure.

The liquid crystal aligning film obtained using the liquid crystal aligning agent of any one of Claims 1-5. A liquid crystal display device comprising the liquid crystal alignment film according to claim 6.