TWI452398B - Alignment material for liquid crystal display device and a preparing method of the same - Google Patents

Description

Alignment material of liquid crystal display element and manufacturing method thereof

The present invention relates to an alignment material for a liquid crystal display element and a method for producing the same, and in particular, the liquid crystal alignment property and the abrasion resistance are excellent, the voltage maintenance ratio and the contrast ratio are high, and the charge accumulation can be reduced by the following Chemical Formula 1 A diaminobenzene derivative, a method for producing the same, and a liquid crystal alignment film using the derivative.

In general, the conventional CRT/cathode ray tube type display element has excellent characteristics, but it is still disadvantageous in that its size and weight increase rapidly as the screen becomes larger, and therefore it is not suitable for use in recent high quality. In order to improve this situation, a large-screen and flat-panel multimedia system has developed a liquid crystal display (LCD).

In the manufacturing process of the liquid crystal display device, the alignment effect of the alignment film is an important factor determining whether the LCD quality is good or not. The alignment film used for the liquid crystal display element basically needs to align the liquid crystal molecules so as to have a proper pretilt angle between the substrate surface and the liquid crystal molecules according to the driving method to form a stable and uniform alignment film, not only that, but also An anchoring energy such as W>10 ^-4 J/cm ² must be formed between the liquid crystal molecules and the alignment film. This is because the alignment film is a factor that determines the reliability of the liquid crystal display element, display uniformity, image sticking, voltage holding ratio, and the like.

At present, various polymer compounds are known as users of liquid crystal alignment films. The most commonly used representative polymer compounds are A polymer composition such as a polyaminic acid type or a soluble polyimide type which is used for the imidization of polylysine. These compositions are widely used in the industry as an alignment agent for alignment of liquid crystals with excellent heat resistance and chemical resistance. Further, the polymer compound is formed by polymerizing a diamine and a tetracarboxylic dianhydride so that the monomer structure exhibits the material properties of the polymer compound.

The basic requirement for the liquid crystal alignment film is the control of the pretilt angle. It is known that the pretilt angle of liquid crystal molecules is greatly affected by the shape of the alignment film surface and the length of the side chain. Especially for the liquid crystal display element of the IPS mode, a low pretilt angle of about 1 to 2 degrees is required.

The driving method of the liquid crystal display element can be divided into a twisted nematic (hereinafter referred to as "TN") mode and a super twist in which nematic liquid crystal molecules are disposed between two transparent substrates on which an alignment film is coated on a transparent electrode. Super twist nematic (hereinafter referred to as "STN") mode, plane switching (In-Plane Switching; hereinafter referred to as "IPS") mode, vertical alignment (hereinafter referred to as "VA") mode, and use A TFT type of a thin film transistor (hereinafter referred to as "TFT").

In the liquid crystal display device of the IPS mode in which the viewing angle is improved, two electrodes which are parallel to each other and have a line shape are formed on all of the two substrates which are parallel to each other. The long axis of the liquid crystal molecules filled in the liquid crystal layer between the two substrates is parallel to the two substrates or parallel to the electrodes, and arranged in a direction forming a certain angle. When an electric field is applied to the two electrodes, the long axis of the liquid crystal molecules is arranged in parallel with the electric field by an electric field parallel to the substrate. However, the existing IPS mode liquid crystal display device has the following problems: that is, there is light leakage in the dark state. Raw, the contrast ratio is lowered, and the response speed of the liquid crystal molecules is slowed down.

The IPS mode uses a transverse electric field mode in which liquid crystal molecules are driven in the same plane, and a viewing angle characteristic of left and right symmetry can be obtained. It is known that an electrode is formed only on one side of the substrate, and a transverse electric field method of applying an electric field in a direction parallel to the substrate is compared with a conventional longitudinal electric field which is formed by applying a voltage to the electrodes of the upper and lower substrates to drive the liquid crystal to have a larger viewing angle characteristic. It can also be used as a liquid crystal display element for high quality display. A liquid crystal display element using such a transverse electric field method is as disclosed in Patent Document 1 below.

As described above, the liquid crystal cell of the transverse electric field type has excellent viewing angle characteristics, but the number of electrode portions formed in the substrate is small, so that it is easy to accumulate static electricity in the liquid crystal cells, and the application of the asymmetric voltage generated by the driving is also The charge is accumulated in the liquid crystal cells, and the problem that the accumulated charge confuses the alignment of the liquid crystal, or the residual image and the residual image persistence affect the display, and the display quality of the liquid crystal element is remarkably lowered. . Therefore, in particular, in the case of a liquid crystal display element for driving a lateral electric field, it is required to display a low pretilt angle (1 to 2 degrees), and in order to reduce residual images, it is necessary to improve the characteristics of the liquid crystal alignment film.

[Patent Document 1] Japanese Patent Application Publication No. H05-505247

In order to solve the problems of the prior art, the object of the present invention is to provide a liquid crystal stable alignment, excellent abrasion resistance, high voltage maintenance ratio and high contrast ratio, low pretilt angle, and especially liquid crystal reduction. A diaminobenzene derivative of a residual image, a method for producing the same, and a liquid crystal alignment film using the derivative.

In order to achieve the above object, the present invention provides a diaminobenzene derivative represented by the following Chemical Formula 1.

In the above Chemical Formula 1, A ₁ to A _{5 are} each independently -H, -F, -CF ₃ , -OCF ₃ , an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, The following chemical formula 2a, 2b, 2c or 2d, and at least one of A ₁ to A ₅ is not -H.

In the aforementioned Chemical Formulas 2a, 2b, 2c, and 2d, R is each independently an alkyl group having 1 to 7 carbon atoms or an alkoxy group having 1 to 7 carbon atoms.

Furthermore, the present invention provides a method for producing a diamine compound according to the above Chemical Formula 1, wherein the production method comprises the following steps: (a) bringing a compound of the following Chemical Formula 3 to 4, 4-dichlorobenzophenone reaction to produce a compound of formula 4; (b) p-toluenesulfonic acid

(p-toluenesulfonic acid) and toluene dehydrate the compound of the above chemical formula 4 to produce a compound of the chemical formula 5; (c) the compound of the above chemical formula 5 and lithium bis(trimethyldecyl)decylamine, (diphenylmethylene) Acetone) palladium or tricyclohexylphosphine is reacted together to produce a compound of the following chemical formula 6; and (d) the compound of the above chemical formula 6 is subjected to hydrogen reduction under a Pd/C catalyst, and the compound is recrystallized and separated.

In the aforementioned Chemical Formulas 3 to 6, A ₁ to A ₅ are as disclosed above.

Moreover, the present invention provides a method for producing a polyimide resin for an alignment agent of a liquid crystal display device, wherein the polyimine resin is represented by the following Chemical Formula 10, and the production method includes the following steps: The diamine compound of the above chemical formula 1, the tetracarboxylic acid anhydride of the following chemical formula 7, and the diamine compound having no side chain group of the chemical formula 8 are reacted under a solvent to produce a polyamic acid-based block of the following chemical formula 9. a copolymer; and, (b) heat-treating the poly-polyamine-based block copolymer, and converting it into a polyimine by a dehydration ring-closure reaction.

In the above Chemical Formulas 7 to 10, X is a tetravalent organic group, Y is a side chain type divalent organic group derived from the above Chemical Formula 1, and Z is a divalent organic group having no side chain group, where m is 1, n It is an integer of 1 or more.

Further, the present invention provides a polyimine resin for an alignment agent of a liquid crystal display device which is produced by the aforementioned method and which has a weight average molecular weight of 1,000 to 200,000.

Moreover, the present invention provides a liquid crystal alignment film which is produced by using a polyimide resin of an alignment agent of the liquid crystal display device.

Moreover, the present invention provides a liquid crystal display element comprising the liquid crystal alignment film described above.

The side chain type diamine compound of Chemical Formula 1 of the present invention can be used as a liquid crystal alignment agent for driving a transverse electric field, and the liquid phase alignment property of the polyimide resin produced by using the above diamine compound is stable and abrasion resistance. Preferably, a low pretilt angle of 1.5 ± 0.2 degrees can be achieved, and the polyimine resin according to the present invention is remarkably improved in terms of contrast ratio and reduction of residual image, and can be used as an alignment agent for a liquid crystal display element.

The invention is described in detail below.

The liquid crystal alignment material of the invention not only can stably align the liquid crystal, has good abrasion resistance, high voltage maintenance ratio and high contrast ratio, and has a low pretilt angle, and particularly reduces the design of the side chain in the state of residual image of the liquid crystal, and uses the chemical formula. A monoamine compound is a feature of the present invention.

The bisamine compound of the above Chemical Formula 1 can be produced by a method similar to that of the reaction formula 1. The method comprises the following steps: in the first stage , after the solution of the compound of the above formula 3 and magnesium dissolved in an ether is cooled to a normal temperature in a nitrogen atmosphere, 4,4- is dissolved in tetrahydrofuran (THF). The solution of dichlorobenzophenone is slowly dropped thereinto to obtain the compound of the above Chemical Formula 4.

Stage 2 The compound of the above chemical formula 4 is in p-toluene sulfonic acid (PTSA). Dehydration under monohydrate provides the compound of Chemical Formula 5.

In the third stage, the compound of the above chemical formula 5 is reacted with lithium bis(trimethyldecyl)guanamine, bis(dibenzylideneacetone)palladium or tricyclohexylphosphine to obtain a diamine compound of the following chemical formula 6. .

Stage 4 The final diamine compound of Chemical Formula 1 can be obtained by subjecting the compound of the above Chemical Formula 6 to hydrogen reduction under a Pd/C catalyst to separate the isomer.

In the aforementioned Reaction Formula 1, A ₁ to A ₅ are as defined above.

Further, the present invention provides a method for producing a polyimine resin using the diamine compound of the above Chemical Formula 1 and a polyimine resin, which is characterized by comprising the following steps: (a) under a solvent The diamine compound of the above Chemical Formula 1, the tetracarboxylic acid anhydride of the following Chemical Formula 7, and the diamine compound having no side chain group of Chemical Formula 8 are reacted to produce a polyamic acid-based block copolymer of the following Chemical Formula 9; (b) The polyamic acid-based block copolymer is heat-treated and converted into a polyimine by a dehydration ring-closure reaction.

Taking a specific example as an example, while maintaining the temperature of 5 ° C, the tetracarboxylic dianhydride of the above Chemical Formula 7 is gradually dropped in a nitrogen atmosphere to the side chain of the above Chemical Formula 1. After the reaction solution obtained by dissolving the diamine compound of the above formula 8 in N-methyl-2-pyrrolidone, the mixture was stirred for 6 hours to produce a polyamic acid-based block copolymer. At this time, the viscosity can be adjusted by a cellosolve solvent such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether or ethylene glycol monobutyl ether.

Thereafter, in the present invention, the polyamic acid-based block copolymer is subjected to heat treatment at 100 ° C to 250 ° C for 30 minutes to 2 hours, and converted into a polyimine by a dehydration ring closure reaction.

Further, the polyaminic acid is stirred at 0 to 180 ° C for 1 to 100 hours in the presence of an alkaline catalyst and an acid anhydride, and can be converted into a polyimide by a chemical imidization reaction. The polyimine solution thus obtained is preferably a precipitated recovery as described above for the synthesis of polylysine.

The solvent used in the production of the above polyamic acid is not particularly limited as long as it dissolves the polylysine produced, and specific examples thereof, such as N-methyl-2-pyrrolidone (NMP), N , N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methyl caprolactam, dimethyl hydrazine (DMSO), γ-butyrolactone, hexa Guanidine phosphate, tetrahydrothiophene oxime, p-chlorophenol, p-bromophenol, 2-chloro-4-hydroxytoluene, dioxane, tetrahydrofuran (THF), cyclohexanone, and the like. Further, even if the solvent which does not dissolve the polyamic acid is used, it may be mixed and used in the solvent in the range of the polyamic acid which does not precipitate. Further, since the water content in the organic solvent serves as a cause of hindering the polymerization reaction and causing the polyamic acid to be produced to be hydrolyzed, it is preferred that the organic solvent is used by dehydration or drying.

The X of the tetracarboxylic dianhydride at the production stage of polylysine is 4 valence Organic base. By way of specific example, 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 4,4'-oxydiphthalic anhydride (ODPA), 3,3', 4,4'-bisphenyltetracarboxylic dianhydride (BPDA), 1,2,4,5-benzenetetracarboxylic dianhydride (PMDA), cyclobutane tetracarboxylic dianhydride (CBDA) and 4-( 2,5-Dioxytetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride (TDA) or the like.

Further, the diamine of the above Chemical Formula 9 or 10 for constituting Y having a nitrogen atom is derived from the diamine of the above Chemical Formula 1. The benzyl derivative linked to the methylene group at the end of the side chain of the diamine can exhibit horizontal alignment, contains many aromatic main chains and side chain diamines, and tetracarboxylic dianhydride can surface The polarity is increased while increasing the surface tension of the alignment film, showing a small pretilt angle. Further, the benzyl group of the linked amine forms a space between the chains to allow the organic solvent to infiltrate, and the solubility can be increased.

Further, as the aforementioned diamine compound of the above Chemical Formula 9 or 10 for constituting Z having a nitrogen atom, a diamine compound having no side substituent may be used. Specifically, 4,4'-diaminodiphenyl ether (ODA), 4,4'-methylenebiscyclohexylamine (PACM), 4,4'-methylene-2-methylcyclohexylamine (ANCAMINE), 4,4'-Methylenediphenylamine, diaminobenzophenone, 4,4'-methylenediphenyldiamine (MDA), 4,4'-hexafluoroisopropyl Diphenyldiamine (6FDA), p-phenylenediamine (p-PDA), and the like.

In order to obtain a polyamic acid, the tetracarboxylic dianhydride component and the diamine component are preferably reacted in an organic solvent at 5 to 100 ° C. When the temperature is high, the combination can be quickly terminated, and the molecular weight of the polymer becomes too high, so it has to be noted. Further, the reaction concentration is 5 to 30% by weight, and uniform stirring is carried out to obtain a desired molecular weight. The obtained polyamic acid can also dilute the reaction solution It is used for release, recovered by precipitation, redissolved and used. The weak solvent to be recovered by precipitation is not particularly limited, and examples thereof include methanol, ethanol, hexane, acetone, butyl cellosolve, methyl ethyl ketone, toluene, benzene, diethyl ether and the like. The polyamine hydrochloride precipitate obtained by the introduction of the weak solvent is filtered, washed, and recovered, and dried at room temperature or under normal pressure or reduced pressure to obtain a solid portion.

For the above polyimine, the side chain type divalent organic group (Y) is used for the function of polyimine such as liquid crystal alignment, solubility and film permeability, and has no side chain 2 The valence organic group (Z) is used to adjust the distribution between the side chains to determine the distribution of the side chain groups. In the aforementioned Chemical Formula 7, m is 1, n is an integer of 1 to 10, more preferably 2 to 4.

The side chain length of the side chain type divalent organic group (Y) is preferably adjusted to be 0.8 to 1.5 times the ratio of the usual length of the long axis of the liquid crystal molecule, and it is preferable to determine the divalent organic group (Z) having no side chain group. The type and amount of use are such that the length between the side chain groups is 1.5 to 3.5 times longer than the length of the long axis of the liquid crystal molecule. In this way, a polyimine resin having a specific structure can be produced, which exhibits excellent alignment property by polyimine, and has characteristics of solubility, film permeability, and chemical stability. Preferably, the polyiminoimine resin preferably has a weight average molecular weight of 1,000 to 200,000.

Moreover, the present invention provides a liquid crystal alignment film using the polyimine resin, which can be obtained by coating an alignment liquid containing the polyimine compound on a patterned substrate and firing the liquid crystal alignment film. The solvent used in the above-mentioned alignment liquid can be dissolved in the liquid crystal alignment liquid, and the polyimine compound can be dissolved, that is, the liquid phase is not particularly limited. It is preferred to contain 1 to 30% by weight of the above polyimine compound.

The liquid crystal alignment film of the present invention is excellent in liquid crystal alignment and abrasion resistance, high in voltage maintenance ratio and contrast ratio, and not only reduces charge accumulation, but also has a pretilt angle of 1 to 2 degrees with respect to nematic liquid crystal, and Residual image.

Hereinafter, the present invention is described in detail based on the following examples, but the scope of the present invention is not limited by the following examples.

[Example 1]

The diamine compound of Chemical Formula 1 is synthesized by the reaction formula 1. The synthesis method will be described below according to each stage.

In the first stage , an iodine tablet and 3.5 g of magnesium were placed in an ether (100 ml) under a nitrogen atmosphere, and the mixture was slowly refluxed. Then, 22.1 g of methylbenzyl bromide was slowly added to 100 ml of ether, and the mixture was further flowed for 2 hours. A Grignard reactant is produced. After cooling the mixture to room temperature, 20 g of 4,4-dichlorobenzophenone was dissolved in 150 ml of tetrahydrofuran (THF), and the mixture was slowly added dropwise thereto, and the mixture was refluxed for 1 hour and 30 minutes. After cooling the reaction mixture, 10 ml of saturated ammonium chloride was added thereto, and the mixture was filtered through Celite, and then extracted with chloroform and sodium chloride, dried over anhydrous magnesium sulfate, and distilled under reduced pressure to give 1,1-bis-( A pale yellow liquid of 4-chloro-phenyl)-2-methylphenylethanol. (25g, 90%)

¹ H NMR (CDCl ₃ , ppm): 7.20 (d, 4H), 7.13 (d, 4H), 7.09 (d, 1H), 6.93 (d, 1H), 6.92 (s, 1H), 6.88 (d, 1H) ), 3.32 (d, 2H), 2.35 (d, 3H), 2.00 (s, 1H)

In the second stage, put 1,1-bis-(4-chloro-phenyl)-2-methylphenylethanol 35g and p-toluenesulfonic acid. 2.7 g of p-toluene sulfonic acid. 1-hydrate was placed in 200 ml of toluene. The solution was further flowed for 12 hours and allowed to react. After confirming the end of the reaction with a TLC plate, the mixture was washed with saturated sodium chloride and ether and then taken. The pressure was dried under anhydrous magnesium sulfate, and the remaining water was distilled to give a pale-colored 1,1-bis-(4-chloro-phenyl)-2-methylphenylethylene liquid. (31g, 95%)

¹ H NMR (CDCl ₃ , ppm): 7.36 (d, 4H), 7.27 (d, 4H), 7.23 (d, 1H), 7.22 (s, 1H), 7.14 (d, 1H), 6.92 (s, 1H) ), 6.91 (d, 1H), 2.35 (d, 3H)

In the third stage , 20 g of 1,1-bis-(4-chloro-phenyl)-2-methylphenylethylene, 43.2 g of lithium bis(trimethyldecyl)guanamine, and 2.6 g of tricyclohexylphosphine were placed. After 5.3 g of bis(dibenzylideneacetone)palladium, 150 ml of toluene (Toliene) was placed. The inside of the reaction vessel was maintained at 90 ° C under a nitrogen atmosphere, and allowed to react for 12 hours. The progress of the reaction was confirmed by GC/Mass. 200 ml of ether was placed, the reaction mixture was diluted, and 300 ml of 1N hydrochloric acid (HCl) was added to complete the reaction. The organic layer obtained by rinsing the organic layer and the aqueous layer with 1N sodium hydroxide and ether was placed in anhydrous magnesium sulfate, dried and filtered. The mixture obtained by subjecting the solvent to distillation under reduced pressure was recrystallized from methylene chloride to give white-1,1-bis-(4-amino-phenyl)-2-methylphenylethylene solid. (9g, 50%)

¹ H NMR (CDCl ₃ , ppm): 7.23 (d, 1H), 7.22 (s, 1H), 7.14 (d, 1H), 7.17 (d, 4H), 6.91 (d, 1H), 6.92 (s, 1H) ), 6.46 (d, 4H), 3.74 (s, broad, 4H), 2.35 (d, 3H)

In the fourth stage, 10 g of 1,1-bis-(4-amino-phenyl)-2-methylphenylethylene was dissolved in benzene and ethanol, and palladium (10 wt% on activated carbon) was placed. 1 g was stirred for 5 hours under a pressure of 4 kg/cm ² . After confirming the completion of the reaction, the mixture was filtered through Celite, and the solution was evaporated under reduced pressure to give a white solid. The solid was recrystallized from ethylene glycol diacetate and ethanol to give a white 1,1-bis-(4-amino-phenyl)-2-methylphenylethane (ethane) solid. (5g, 50%)

¹ H NMR (CDCl ₃ , ppm): 7.09 (t, 1H), 6.93 (d, 1H), 6.92 (s, 1H), 6.88 (d, 1H), 6.87 (d, 4H), 6.41 (d, 4H) ), 4.44 (t, 1H), 3.74 (s, broad, 4H), 3.17 (d, 2H), 2.35 (d, 3H)

[Embodiment 2]

Synthesis of 1,1-bis-(4-amino-benzene in the same manner as in Example 1 except that fluorobenzyl bromide was used instead of the methylbenzyl bromide of the first stage of Example 1. Base)-2-fluorophenylethane (ethane). (5g, 20%) ¹ H NMR (CDCl ₃ , ppm): 7.19 (t, 1H), 6.89 (d, 1H), 6.87 (s, 1H), 6.79 (d, 1H), 6.87 (d, 4H) , 6.41 (d, 4H), 4.44 (t, 1H), 3.75 (s, broad, 4H), 3.17 (d, 2H)

[Example 3]

1,1-bis-(4-amino-phenyl)-2-methylphenylethane (ethane) 6.3 g and 4,4'-diaminodiphenyl ether (ODA) 8.3 under nitrogen atmosphere g was dissolved in 122 g of N-methyl-2-pyrrolidone, and 20 g of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) was added while maintaining at 5 °C. The remaining N-methyl-2-pyrrolidone 132 g was slowly dropped over 2 hours, and reacted for 10 hours. The reaction solution was placed in an excess of ultrapure water, and the deposited precipitate was filtered.

The filtrate was washed with methanol, and dried under reduced pressure in a vacuum oven at 50 ° C to obtain polylysine. (weight average molecular weight = 60,000)

[Example 4]

In addition to 3,3',4,4'-bisphenyltetracarboxylic dianhydride (BPDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride used in the foregoing Example 3 was replaced. The polyamic acid solid portion was obtained in the same manner as in Example 3 except for (BTDA). (weight average molecular weight = 70,000)

[Example 5]

In addition to the use of 1,1-bis-(4-amino-phenyl)-2-fluorophenylethane (ethane) in place of the 1,1-bis-(4-amino-benzene used in the foregoing Example 3. The base was 2-methylphenylethane (ethane), and the same was obtained in the same manner as in Example 3 to obtain a solid portion of polylysine. (weight average molecular weight = 60,000)

[Embodiment 6]

In addition to the use of 1,1-bis-(4-amino-phenyl)-2-fluorophenylethane (ethane) in place of the 1,1-bis-(4-amino-benzene used in the foregoing Example 3. 2-methylphenylethane (ethane), and replaces 3,3',4,4'-di with 3,3',4,4'-bisphenyltetracarboxylic dianhydride (BPDA) The polyamic acid solid portion was obtained in the same manner as in Example 3 except for benzophenonetetracarboxylic dianhydride (BTDA). (weight average molecular weight = 70,000)

[Comparative Example 1]

In addition to 1,1-bis-(4-amino-phenyl)-2-phenylethane (ethane), the 1,1-bis-(4-amino-phenyl) used in the foregoing Example 3 was replaced. The polyamic acid solid portion was obtained in the same manner as in Example 3 except for -2-methylphenylethane. (weight average molecular weight = 60,000) The physical property evaluation method uses the following method.

(1) Weight average molecular weight of the polymer To calculate the weight average molecular weight of the polymer, gel permeation chromatography (GPC) was determined. The residence time of the column in which the dimethyl acetamide (DMAc) was used as the mobile phase and filled with the polymer substance was measured at 60 ° C, and the average molecular weight and residence time of the styrene polymer were corrected to calculate the poly The average molecular weight of the solid portion of the proline. The polymer constituting the liquid crystal alignment agent has a value of a weight average molecular weight of about 1,000 to 200,000 g/mol.

(2) Pretilt angle of liquid crystal display element The He-Ne laser light is used by the method disclosed in the literature (T.J. Schffer, et. al., J., Appl., Phys., vol. 19, 2013 (1980)) by the crystal rotation method.

(3) Orientation of liquid crystal The presence or absence of an abnormal domain in the liquid crystal cell when a voltage is applied to the liquid crystal display element and when no voltage is applied is observed by a microscope, and the type of the abnormal field is judged as "good".

(4) Voltage maintenance ratio of liquid crystal display element After applying a voltage of 5 V to the liquid crystal display element for 60 μsec, the voltage holding ratio after 16.67 msec after the release of the applied state was measured.

(5) Contrast ratio The liquid crystal display element was measured for the light transmittance at a voltage (bright state) at which the light transmittance and the light transmittance at the time of no voltage application (dark state) were maximum.

(6) Residual image evaluation A liquid crystal alignment agent was printed on a substrate having a zigzag electrode (super-IPS) having an electrode width of 5 μm and a gap of 10 μm between the electrodes, and dried and baked to prepare a film having a film thickness of 200 nm (substrate 1). Similarly, a liquid crystal alignment agent was printed on an electrodeless glass substrate, and dried and baked to prepare a film having a film thickness of 200 nm (substrate 2). The substrate 1 is subjected to a rubbing treatment so that the liquid crystal alignment agent has an angle of 20 degrees toward the electrode direction. Further, the substrate 2 was subjected to a rubbing treatment to make the substrate 1 parallel to the rubbing direction, and a spacer was spread on the substrate, and the cells were bonded to each other to form cells having a gap of 4 μm, and liquid crystal MJ991735 (manufactured by a foreign company Merck) was injected into the cells to prepare a substrate. Liquid crystal cells. The liquid crystal cells were applied at a rate of 0.1 V/s and a frequency of 1 kHz between 0 and 10 V, and the voltage-transmittance (V-T) characteristics of the liquid crystal cells were measured, and then a direct current voltage of 10 V was applied for 30 minutes. Immediately after the DC voltage was turned off, the V-T characteristic was measured, and the residual image was evaluated from the change in the voltage-transmittance characteristics before and after the application of the DC voltage. That is, when the V-T characteristic changes, and the transmittance when a certain voltage is applied is changed, the change can be observed in the field as a residual image.

Further, the solid portions of the polyamic acid produced in the above Examples 3 to 6 and Comparative Example 1 were placed in a solvent in which NMP and 2-butoxyethanol were mixed in a weight ratio of 3:1 to obtain a concentration of 4 parts by weight. % solution. The solution was filtered through a 0.1 μm filter, and coated on the glass substrate on which the transparent conductive film had been patterned by spin coating. The thickness. After coating, it was prebaked at 90 ° C for 3 minutes, and then baked at 210 ° C for 1 hour to obtain a substrate on which a polyimide film was formed.

In addition, the alignment film obtained by using two glass substrates, such as a glass substrate with a comb-shaped electrode for IPS and a glass substrate without an electrode, was ultrasonically washed in ethanol for 3 minutes, and then washed with ultrapure water. The net surface was then dried in an oven, spread with a spacer material of 4 μm, bonded, and then filled with liquid crystal, sealed with an epoxy curing agent to produce liquid crystal cells. The characteristics of the liquid crystal cells thus produced are shown in Table 1 below.

As shown in the above-mentioned Table 1, it is confirmed that all of the examples 3 to 6 and the comparative example 1 of the present invention have excellent characteristics as the liquid crystal alignment agent for driving a transverse electric field, and the voltage maintenance ratio and the alignment property are also excellent. In particular, the above-described Examples 3 to 6 can be confirmed, and the residual image is remarkably reduced as compared with Comparative Example 1.

Claims (9)

A diaminobenzene derivative which is represented by the following Chemical Formula 1: In the above Chemical Formula 1, A ₁ to A _{5 are} each independently -H, -F, -CF ₃ , -OCF ₃ , an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, The following chemical formula 2a, 2b, 2c or 2d, and at least one of A ₁ to A ₅ is not -H; In the aforementioned Chemical Formulas 2a, 2b, 2c, and 2d, R is each independently an alkyl group having 1 to 7 carbon atoms or an alkoxy group having 1 to 7 carbon atoms. A method for producing a diamine compound, which is the diaminobenzene derivative of claim 1, wherein the above production method comprises the following steps: (a) bringing a compound of the following chemical formula 3 to 4,4- Dichlorobenzophenone reaction to produce a compound of Chemical Formula 4; (b) dehydration of the compound of Chemical Formula 4 with p-toluenesulfonic acid and toluene to produce a compound of Chemical Formula 5; (c) a compound of the formula 5 is reacted with lithium bis(trimethyldecyl)guanamine, palladium (diphenylmethyleneacetone) or tricyclohexylphosphine to produce a compound of the following chemical formula 6; and (d) is a Pd/C The compound of the above Chemical Formula 6 is subjected to hydrogen reduction under a catalyst, and the compound is recrystallized and separated; In the above Chemical Formulas 3 to 6, A ₁ to A ₅ are as described above. A method for producing a polyimide resin for an alignment agent of a liquid crystal display device, wherein the polyamidene resin is represented by the following Chemical Formula 10, wherein the production method comprises the following steps: (a) using a solvent The diaminobenzene derivative of claim 1, the tetracarboxylic acid anhydride of the following Chemical Formula 7, and the diamine compound having no side chain group of Chemical Formula 8 are reacted to produce a polyamic acid-based block copolymer of the following Chemical Formula 9 And (b) heat-treating the poly-polyamine-based block copolymer, and converting it into a polyimine by a dehydration ring-closing reaction, In the above Chemical Formulas 7 to 10, X is a tetravalent organic group, Y is a side chain type divalent organic group derived from the diaminobenzene derivative, and Z is a divalent organic group having no side chain group, and here, m Is 1, n is an integer of 1 or more. The method for producing a polyimine resin for an alignment agent of a liquid crystal display device according to claim 3, wherein in the chemical formula 10, n is an integer of from 1 to 10. The method for producing a polyimine resin for an alignment agent of a liquid crystal display device according to claim 3, wherein the solvent is selected from N-methyl-2-pyrrolidone (NMP), N, N-dimethyl Carbenamide (DMF), dimethyl hydrazine (DMSO), hexamethyl sulfo decylamine, tetramethyl hydrazine, p-chlorophenol, p- bromophenol, 2-chloro-4-hydroxytoluene, two One or more solvents selected from the group consisting of oxane, tetrahydrofuran (THF), and cyclohexanone. A polyimine resin for an alignment agent for a liquid crystal display device, which is produced by the production method of claim 3, and has a weight average molecular weight of 1,000 to 200,000. The polyimine resin according to claim 6 , wherein the side chain length of the polyimine is 0.8 times to 1.5 times the length of the long axis of the liquid crystal molecule, and the length between the side chains is 1.5 of the long axis length of the liquid crystal molecule. Up to 3.5 times. A liquid crystal alignment film produced by using a polyimide film for an alignment film of a liquid crystal display device of claim 6 of the patent application. A liquid crystal display element comprising the liquid crystal alignment film of claim 8 of the patent application.