TW200420982A - Liquid crystal alignment layer forming method - Google Patents

Abstract

The present invention provides a liquid crystal alignment layer forming method, comprising a step of coating a substrate with a liquid crystal aligning agent containing soluble polyimide and polyamic acid and a step of irradiating the substrate with polarized ultraviolet radiation. According to the invention, a liquid crystal alignment layer can be formed with excellent workability and with excellent uniformity and used for a liquid crystal display device with little stored charge. Therefore a liquid crystal display device having this liquid crystal alignment layer can continue to display an image of high contrast without causing image persistence because of the little charge storage. The invention is a high versatility technique leading to improvement of electrical characteristics, and further leading to improvement of the quality of image of any type of liquid crystal device including display devices such as of not only the TFT liquid crystal currently used in the mainstream, but also the VA liquid crystal and the IPS liquid crystal.

Description

200420982 (1) 发明. Description of the invention [Technical field to which the invention belongs] The present invention relates to a method for forming a liquid crystal alignment film capable of obtaining a liquid crystal display element with uniform liquid crystal alignment and low ghosting. [Prior art] As a thin and light display device, liquid-liquid components have been widely used in personal computers, televisions, word processors, and so on. More important than the liquid crystal material used is the liquid crystal alignment film which aligns liquid crystals uniformly. In particular, in recent years, as the size of liquid crystal display elements has increased, efficient and uniform processing of liquid crystal alignment films has become important. In addition, with the increase in the definition of liquid crystal display elements, afterimages on display screens or the problem of "ghost images" are being generated. In order to suppress this phenomenon, liquid crystal alignment films that are difficult to accumulate electric charges are strongly required. At present, an organic resin is mainly used for a liquid crystal alignment film. After being coated on a substrate, firing is performed, and then pressure is applied to the surface of the liquid crystal alignment film by a holm or nylon cloth, that is, a so-called "surface grinding treatment" is formed. For surface-treated liquid crystal alignment film 'To improve the characteristics, a liquid crystal alignment agent containing soluble polyamidoimide and polyamidoamine is used to form a coating film. A method for forming a surface-polished liquid crystal alignment film has been disclosed (for example, refer to Japan Japanese Patent Laid-Open No. 08-22 0 54 1). However, the surface grinding process is a physical process, and it is difficult to uniformly handle a large area of the liquid crystal alignment film, and there are problems of poor operation such as dust generation and static electricity generation. -4-(2) (2) 200420982 In recent years, various proposals have been made for the formation method of the liquid crystal alignment film s', that is, the "light alignment method", which is irradiated with polarized ultraviolet rays (for example, refer to Japanese Laid-Open Patent Publication No. 0 9-2 9 7 3 1 Bulletin 3). The development method of the alignment film using the photo-alignment method uses a polarized ultraviolet ray, and the uniformity and workability of the alignment of the liquid crystal are good ', but the characteristics such as the ghost phenomenon cannot be satisfied. [Summary of the Invention] In view of the foregoing, the present invention provides a method for forming a liquid crystal alignment film with good uniformity and good workability, and with less charge accumulation. As a result of intensive review by the present inventors, a resin system containing polyamidoamine and soluble polyamidoimide was used as a liquid crystal alignment agent, and after coating it on a substrate, it was found that it can form uniformity and good workability by irradiation with polarized ultraviolet rays. 'Also, it is an excellent liquid crystal alignment film with less charge accumulation when used as a liquid crystal display element. That is, the present invention mainly has the following features. (1) a method for forming a liquid crystal alignment film, a coating step of applying a resin containing polyfluorene and soluble polyimide as a liquid crystal alignment agent to a substrate; and a step of irradiating a coating film obtained on the substrate with polarized ultraviolet rays; A liquid crystal alignment film is then formed. (2) The method for forming a liquid crystal alignment film according to the above (1), wherein the soluble polyimide-based diacid anhydride having an alicyclic structure is reacted with a diamine to obtain a soluble polyfluorene imine resin. (3) The method for forming a liquid crystal alignment film as described in (1) or (2) above, wherein the 'soluble polyfluorene imide contains the general formula (1) which represents a repeating single -5- (3) 200420982 position.

(1) (In the formula, R! Represents a divalent organic group) φ (4) The method for forming a liquid crystal alignment film as described in any one of (1) to (3) above, wherein the polyamide contains the general formula (2) Represents repeating units.

(In the formula, R2 represents a divalent organic group.) (5) The method for forming a liquid crystal alignment film according to any one of (1) to (4) above, wherein the soluble polyfluorene imine / polyfluorene included in the liquid crystal alignment agent The weight ratio of amine is 0.01 to 99.0 / 1. (6) The method for forming a liquid crystal alignment film according to any one of (1) to (5) above, wherein the concentration of the soluble polyimide and polyimide contained in the liquid crystal alignment agent is 0.1 to 30% by weight. (7) The formation of the liquid crystal alignment film according to any one of the above ()) to (6) (4) 200420982 method, wherein the irradiation wavelength of polarized ultraviolet light is 1 50 to 400 nm, and the irradiation intensity is 1 to 6 0 J / em 2. (8) The method for forming a liquid crystal alignment film according to any one of (1) to (7) above, wherein the thickness of the coating film is 5 to 300 nm. [Embodiment] The most important point of the present invention is to use a resin containing soluble polyimide and polyimide as a liquid crystal alignment agent, apply it to a substrate, and then irradiate polarized ultraviolet rays, that is, use the photo-alignment method. Therefore, a liquid crystal alignment film using a photo-alignment method with high uniformity and good workability is formed, and a liquid crystal display element using the liquid crystal alignment film is found to be difficult to cause ghosting due to its good electrical properties, particularly the accumulation of residual charges. The polyamine-based diamine used in the present invention is a condensate obtained by reacting an acid anhydride. The following examples are diamine compounds used as raw materials when synthesizing polyfluorene. As an example of an alicyclic diamine,

Benzene, 2,2-bis (4-aminophenyl) propane, 2,2, diaminostilbene, 4,4, -4,4'-diaminodiphenylmethane, aminostilbene , 4,4, -diamine (5) (5) 200420982 diphenyl ether, 4,4'-diphenyl sulfide, 4,4'-diamine diphenyl maple, 3,3 diamine Diphenylphosphonium, 2-diaminobenzoic acid phenyl ester, 2,2'-diaminobenzophenone, 4,4'-diaminobenzyl, bis (4-aminophenyl) methylphosphine oxide , Bis (3-aminophenyl) fluorene, bis (4-aminephenyl) phenylphosphine oxide, bis (4-aminephenyl) cyclohexylphosphine oxide, N; N-bis (4-aminephenyl)- N-aniline, N; N-bis (4-aminophenyl) -N-methylamine, 4,4'-diaminodiphenylurea, 1 5 8-diaminonaphthalene, 1,5-di Aminonaphthalene, I 5 -diaminoanthracene, diaminoglycans (eg 2,6-diaminobuckwheat), bis (Iaminophenyl) diethylsilane, bis (4-aminophenyl) diamine Methylsilane, bis (4-aminophenyl) tetramethyldisilazane, 4- (3-aminophenyl) aniline, benzidine, 2,2'-dimethylbenzidine, 2,2-bis [4- (4-aminephenoxy) phenyl] propane, bis [4- (4-aminephenoxy) benzene ] 飒 ,, 4; 4'-bis (4-aminephenoxy) biphenyl, 2,2-bis [4- (4-aminephenoxy) phenyl] hexafluoropropane, 1,4-bis ( 4-aminephenoxy) benzene, 1,3-bis (4-aminephenoxy) benzene. Further, as the heterocyclic diamines, for example, 2,6-diaminopyridine, 2,4-diaminopyridine, 2,6-diamino-s-tri (till), 2,5-diamine Amino-diphenylfuran, 2 5 7-diaminocarbazole, 3,6-diaminocarbazole, 3,7-diaminophenothiazine, 2; 5-diamino-1,3, 4-thiadiazole, 2,4-diamino-6-phenyl-s-tri (co-), etc. Examples of aliphatic diamines are 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1; 5-diaminopentane, 1,6 -Diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1; 9-diaminononane, 1,10-diaminodecane, 1,3 -Diamino-2,2-dimethylpropane, diamino-2,5-dimethylhexane,], 7-diamino-2,5-dimethylheptane,]., 7 -Diamino-4,4-dimethylheptane, 1,7-diamino-3-methylheptane (6) 200420982 alkane, 1,9-diamino-5 -methylnonane, 2 , 1 1 · diaminodecane, 1,12 -diaminooctadecane, 1,2-bis (3-aminopropyloxy) ethane, etc.

= > nh2 ⑶ (In the formula, R3 represents a long-chain alkyl group or a perfluoroalkyl-containing monovalent organic group having 6 or more carbon atoms, preferably an alkyl group or a perfluoroalkyl group having 6 to 18 carbon atoms. A monovalent organic group such as an aromatic diamine having a long-chain alkyl group or a perfluoro group. Of course, the above-mentioned diamines used as raw materials of polyamines can be used individually or in combination. When at least one of them contains an aromatic diamine containing a long-chain courtyard group or a perfluoro group represented by formula (3), the hydrophilicity is low. It is more suitable because the water absorption is improved. _ Diacids used as raw materials when synthesizing polyamines as aromatic dianhydrides such as pyromellitic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,353,54, -biphenyl Pyromellitic dianhydride, 3,3'4,4, benzophenone tetraacid dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) 飒Dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, etc. Examples of the alicyclic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, and 2,3,4,5-tetrahydrofuran. Tetraacid dianhydride, 1,2,4,5-cyclohexanetetraacid dianhydride,]: 2-dicarboxyl-〗-(3,4-diresidual cyclohexyl) ethane (7) 200420982 dianhydride, 1,2-Dicarboxy-1- (3,4-dicarboxy-1,2,3,4-tetrahydronaphthyl) ethane dianhydride. These dianhydrides may be used alone or in combination. Among these, from the viewpoint of improvement in heat resistance, polyamines having a repeating structure represented by the general formula (2) obtained by reacting an acid anhydride of a pyromellitic acid and a diamine are preferred.

In the polyamidoamine used in the present invention, the above diamine and dianhydride are in the presence of an organic solvent at -20 ° C to 150 ° C and 0 to 80 ° C. (: Preferably, 30 minutes to 24 hours, preferably 1 to 10 hours, and synthesized by reaction. The mole ratio of the limbs and dianhydride used in the reaction will not increase if the amount of diamine is too much, but When the residual acid anhydride is low, storage stability is deteriorated, so diamine / dianhydride = 0.5 to 3.0 / 1.〇 (molar ratio) is preferred, and diamine / dianhydride = 0.8 to 2.〇 / 1 〇 (mol ratio) is better, of which diamine / dianhydride ==〗 · 〇〜〗 · 2 / 1〇 (mol ratio) is particularly good. By polymerizing the polymer: 'The solvent used in the synthesis and No special limit

system. As the solvent, polymers with hydrazine, N-methyl-2 -pyrrolidone, tetramethylurea, pyridine, and dimethyl are highly soluble, so they are more suitable for varnish handling. If it is low, the molecular attack cannot be improved, and it is preferably -10- (8) 200420982] to 50% by weight, more preferably 5 to 30% by weight, and particularly preferably 8 to 20%. Also, in the range where the polymer is dissolved, a lean solvent such as butyl cellosolve benzene and methanol may be added. Furthermore, in order to increase the molecular weight of polyamine easily, the reaction system is preferably in a gaseous environment, and the reaction is more preferably performed while nitrogen gas is generated in a solvent in the reaction system. If the reduction viscosity of the final polyamide solution is high, it is difficult to take it, and when it is low, the characteristics of the alignment film cannot be stabilized. Good (temperature: 30 ° c, 2-pyrrolidinone, concentration: 0.5 g / d 1). The soluble polyfluorene imide of the present invention is obtained by synthesizing polyfluorene in the same manner as polyfluorene, and then condensing all or part of the polyfluorene by ring-closing (fluorine imidization). Here, the soluble polyfluorene imide of the present invention preferably contains an alicyclic structure in the polymer from the viewpoint of improving permeability. Among them, the diacid anhydride of I2 · dicarboxy-1 · (3,4-dicarboxy-1,2,3,4-tetrahydronaphthyl) ethane is reacted with diamine to synthesize polyamidoamine, and then diamine it. Aminated soluble polyfluorene imide containing a repeating structure represented by general formula (1) is particularly suitable when it has excellent electrical characteristics as a liquid crystal display element. When the weight of a formic acid is immersed in nitrogen, the clarity obtained by the N-form method includes dianhydride,

-11-200420982 〇) The method for synthesizing polyfluorene imine in the present invention, that is, the method of polyfluorene imine ring closure (fluorene imidization) to obtain polyfluorene imine is not particularly limited. Method, a method for chemical hydrazone imidization using a catalyst, and the like. Among them, polyimide is preferably obtained by a method of performing chemical imidization with a catalyst in order to make the reaction easy to cause and difficult to cause side reactions. That is, after synthesizing polyamidoamine, in the presence of 2 to 20 moles of alkaline catalyst of amidine and 3 to 30 moles of anhydride of amidine, at -20 to 300 ° C, The temperature is preferably 0 to 250 ° C, and the reaction is preferably 1 to 100 hours. When the amount of the basic catalyst and the acid anhydride is small, the reaction cannot be performed sufficiently, and when the amount is too large, it is difficult to completely remove the reaction after the reaction is completed. In addition, as the basic catalyst used herein, for example, pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like can be used. Among them, the reaction with pyridine can maintain a moderate testability. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic acid. Among them, when acetic anhydride is used, it is more suitable because it can be easily purified after the reaction. In addition, if the polyamidoamine is imidized, the reaction rate of the polyamidoamine (amidoimidization) is too low, and the electrical properties at the time of liquid crystal display are deteriorated. If it is too high, the synthesis time is long, so 1 ~ 99.9 ° . Preferably, 20 to 99.5% is more preferable, and 50 to 99% is particularly preferable. The soluble polyfluorene imide lacquer thus obtained can be purified by injecting a poor solvent and reprecipitating it while stirring. The lean solvent used at this time is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene. The polyimide resin obtained by reprecipitation was filtered and recovered, and then dried under normal pressure or reduced pressure at normal temperature or by heating to form a powder. This powder is re-dissolved in a good solvent and re-precipitation is repeated 2 to 10 times. Impurities in the polymer are reduced. When used as a liquid crystal alignment film, -12- (10) (10) 200420982 has good electrical properties, so it is suitable. In this case, it is suitable to use three or more kinds of lean solvents, such as alcohols, ketones, and hydrocarbons, as the lean solvent because the purification efficiency can be further improved. The polyfluorene imide resin thus obtained can be redissolved in a solvent containing a good solvent used in the synthesis. In the present invention, a liquid crystal alignment agent can be obtained by blending the soluble polyamidine and polyamidine thus obtained. At this time, although there is no particular restriction on the order and method of compounding, the results of the intensive review by the inventors and others, as the weight ratio of the amount of soluble polyfluorene imine / polyamide, is preferably 0.0 1 to 9 9 · 0/1, 〇. 〇3 ~ 1. 0/1 is more preferable, 0 · 0 5 ~ 0 · 8/1 is particularly preferable, and an alignment film having excellent electrical properties can be obtained as a liquid crystal display element. In addition, when forming a liquid crystal alignment film, the film thickness is uniform, and the solvent used during the formulation includes N, N-dimethylformamide, NA-dimethylacetamide, and N-methyl-2. -Good solvents such as pyrrolidone, N-methylcaprolactone, dimethyl sulfene, tetramethylurea, pyridine, or butyrolactones: 30 to 9 9.9% by weight, butyl cellulose, toluene , Methanol and other poor solvents: 0 · 1 to 70% by weight of a mixed solvent is preferred. The concentration of the soluble polyfluorene imine and polyfluorene of the liquid crystal alignment agent of the present invention is too low when the liquid crystal alignment film is thin, and the reliability as a liquid crystal display element is deteriorated. When the concentration is too high, the film thickness is damaged when coated on a substrate Uniformity is preferably from 0 to 30% by weight, and particularly preferably from 1 to 10% by weight. The liquid crystal alignment agent thus obtained in the present invention can be used as it is. If a coupling agent is added, the adhesion between the liquid crystal alignment film and the substrate is better. The coupling agent here refers to a compound having silicon and at least one element selected from the group consisting of completely typical metal elements and complete transition metal elements belonging to groups 1 to 3 of the periodic table. 13- (11) 200420982 is jointly bonded with an oxygen atom. Compounds. In particular, a coupling agent having an alkoxysilane, aluminum, chromium alkoxide, and titanium alkoxide structure is easy to obtain and suitable for price. Among them, 3-aminopropyltrimethoxysilane has a particularly high electrical property when used as a liquid crystal element. . In addition, if the content of the coupling agent is large, the strength of the film is weakened, and the effect of improving the adhesiveness is small if the content of the coupling agent is small. 〇. 5 ~ 10 10% by weight is particularly preferred. The above-mentioned coupling agent is prepared. After the coupling agent is diluted with a solvent, the liquid crystal alignment agent is injected little by little at a temperature of -5 to 80 ° C. Since it is not easy to thicken and the resin is insoluble, it becomes a uniform liquid crystal alignment agent, so it is more suitable. In addition, at this time, the solvent and concentration of the diluent coupling agent are not particularly limited, and N-methyl-2-[i-pyrrolidone, dimethylacetamide, dimethylformamide benzene, hexane, and γ- Solvents such as butyrolactone are preferred, preferably diluted to a concentration of from 50% to 50%, more preferably from 3 to 30% by weight. To the liquid crystal alignment agent thus obtained, various agents such as a cross-linking agent may be added and used. In addition, the obtained liquid crystal alignment agent is used after filtering, and the method for forming a liquid crystal alignment film of the present invention obtains the liquid crystal alignment agent of polyimide and polyimide from the above, which is applied in a base step and irradiated with polarized ultraviolet rays. A method for forming a liquid-directed film formed on a substrate step. For the step of applying the liquid crystal alignment film to the substrate, a method such as a spin coating printing method or an inkjet method can be used. In this case, the substrate to be used is not particularly limited, and a plastic substrate such as a glass substrate, a force substrate, or a polycarbonate substrate can be used. Moreover, the use of alkoxy is excellent to show the alignment. The alignment:% will cause it. And for example, A weight added Gui. From the viewpoint of simplification of the manufacturing process, a substrate-containing crystal matching method is suitable for forming substrates such as -14- (12) (12) 200420982 for driving liquid crystal from the viewpoint of simplifying the manufacturing process. Apply a liquid crystal alignment agent on these substrates, and dry at 50 to 300 ° C, preferably 80 to 20 ° C (TC temperature, ^ 200 minutes to form a liquid crystal alignment; ^ coating film. If the coating film formed is too thick, In terms of price, the guilty degree of the thin 5-toned liquid crystal is reduced, preferably 5 to 300 nm, more preferably 7 to 1000 nm, and particularly preferably 10 to 80 nm. The substrate step is a step of aligning the coating film surface with a polarized ultraviolet ray such that the coating film becomes a liquid crystal alignment film. The irradiation wavelength of the polarized ultraviolet ray is preferably 150 to 400. nm, more preferably 190 ~ 380 nm, particularly preferably 22 0 ~ 350 nm, and irradiation intensity is preferably 丨 ~ ⑹j / cm2, more preferably 20 ~ 50J / cm2, particularly preferably 25 ～ 40 J / cm2. If the irradiation wavelength of polarized ultraviolet rays is too short, the liquid crystal alignment energy of the liquid crystal alignment film will be deteriorated. If it is too long, the light resistance will be deteriorated. Also, if the irradiation intensity is too weak, the liquid crystal alignment energy will be deteriorated and too strong. The electrical properties deteriorate. The alignment direction of the obtained liquid crystal alignment film is determined by the polarization direction of the irradiated ultraviolet rays. As described above, the liquid crystal alignment film formed by the method of the present invention can uniformly align liquid crystals. Since the accumulated charge is small, using the liquid crystal alignment film, the liquid crystal alignment can be uniform to obtain a liquid crystal display element with little ghosting. A conventional method may be used to obtain a liquid crystal display element using the liquid crystal alignment film formed by the method. As an example thereof, for example, a substrate with a liquid crystal alignment film interposed therebetween is preferably 1 to 3 μm, more The method is preferably a spacer with a size of 2 to 20 μm, an orientation direction of which is set to an angle of 0 to 270 G, and a method of injecting liquid crystal and then packaging it to obtain a liquid crystal display element. Sealing -15- (13) (13) 200420982 Liquid crystal There is no particular limitation on the method, for example, the vacuum method of depressurizing the produced liquid crystal intracellularly and injecting the liquid crystal into the liquid crystal method of dropping the liquid crystal and then encapsulating it. The liquid crystal display element produced by using the present invention has uniform liquid crystal alignment, It becomes a liquid crystal display device in which ghosting is difficult to occur. Hereinafter, the present invention will be specifically described using examples, but the present invention is not limited to these explanations. Examples (Synthesis Example 1) 50000 m1 Two round flasks were connected to a nitrogen introduction tube and a chlorinated bromide tube. 9.73 g (0.09 mol) of p-phenylenediamine and 3.49 g of hexadecyloxydiaminobenzene (0.0 1 Mol) is stirred in 5 5 g of N-methyl-2 -pyrrolidone (hereinafter referred to as NMP) to completely dissolve it. Then, 1,2-dicarboxy-1- (3,4-dicarboxy- 1,2,3,4-tetrahydronaphthyl) ethane dianhydride 30 · 03 g (0.1 mol), and reacted at room temperature for 10 hours to synthesize polyamine. In this polyamine 1 0.006 g of acetic anhydride 21.6 g (0.2 12 mol) and pyrene 9.97 g (0.126 mol) were added as the imidization catalyst, and the reaction was carried out at 50 ° C for 3 hours. A polyimide resin solution was prepared. This solution was poured into 100 m 1 of methanol to obtain a white precipitate, which was filtered and dried to obtain a white polyfluorene imine resin. This resin was re-dissolved in NMP, and then acetone was added. Similarly, the obtained white precipitate was filtered and dried to obtain a white polyimide resin. The reduced viscosity of the obtained polyimide was 0.64 dl / § (0.5% by weight NMP solution, 30 ° C). 7.2 g of this powder was dissolved in 2.8 g of butyrolactone 11 to obtain a solvent-soluble polyfluorene imide resin having a solid content concentration of 6%. -16- (14) 200420982 (Synthesis Example 2) In a 500 ml three round flask, a nitrogen introduction tube and a calcium chloride tube were connected, and 19.827 g of 4,4'-diaminodiphenylmethane was placed in a nitrogen atmosphere. (0.1 mol) was dissolved in 6 g of NMP22, and then 10.687 g (0.049 mol) of pyromellitic dianhydride and 9.60 g (1,249,4-tetracarboxycyclobutane dianhydride) were added (0.049 mol). After 10 hours of reaction at room temperature, polyamine was synthesized. The reduced viscosity of the obtained polyimide was 1.18 dl / g (0.5% by weight NMP solution, 30 ° C). This solution was diluted with γ-butyrolactone to a solution concentration of 6% to obtain a polyamide resin solution. (Deployment example 1)

In Synthesis Example 1, 20 g of a 6% soluble polyfluorene imide solution was obtained, and in Synthesis Example 2 was a 6% polyamidamine solution, 80 g. In a 300 ml Erlenmeyer flask, the mixture was stirred at room temperature for 1 2 After hours, dilute with NMP to make it 4%. Coupling agent 1 ^ -3450 (manufactured by Yotsu Chemical Co., Ltd., trade name) ○ 12 g was diluted with 2 g of NMP and added to the solution, followed by stirring for 12 hours. The resulting varnish becomes a liquid crystal alignment agent. (Preparation Example 2) 100 g of a soluble polyfluoreneimide solution having a concentration of 6% obtained in Synthesis Example 1 was diluted with NMP to a concentration of 4%. Coupling agent LS-34.5 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.12 g was diluted with 2 g of NMP and added to the solution, followed by stirring for 12 hours. The resulting varnish becomes a liquid crystal alignment agent. -17- (15) (15) 200420982 (Preparation Example 3) The 6% concentration polyamidamine solution obtained in Synthesis Example 2 was diluted with NMP to a concentration of 4%. Coupling agent LS_ 3 4 5 0 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 g was diluted with 2 g of NMP and added to the solution, followed by stirring for 12 hours. The resulting varnish becomes a liquid crystal alignment agent. (Example 1) The liquid crystal alignment agent obtained in Formulation Example 1 was spin-coated on a glass substrate with an electrode, and was fired in a hot-air circulation type dryer at a temperature of 20 nm to a thickness of 50 nm.醯 imine film. This coating film was irradiated with polarized ultraviolet rays of 30 J / cm to obtain a substrate with a liquid crystal alignment film. When the surface of the alignment film of the substrate with a liquid crystal alignment of 0 nm was observed under a microscope, it was found that: > A liquid crystal alignment film having a non-destructive surface and no cloud-like defects (mura) was uniformly formed. Moreover, in order to measure the electrical properties of the liquid crystal cell, two such substrates were made, and after spreading 6 μηι spacers, a sealant was printed on one side, and the two substrates at approximately right angles to the light irradiation direction had their polyimide films facing each other. Inside then sealed. This liquid crystal cell was decompressed, and then injected into a liquid crystal M L C-2 0 3 (manufactured by Japan Merck, trade name) 'to prepare a liquid crystal cell. A polarizing plate is placed on the liquid crystal cell, and a backlight is arranged under the liquid crystal cell. When the liquid crystal cell is rotated at 90 degrees, the light transmittance is changed to display light and dark, and it can be confirmed that the liquid crystal is indeed aligned. Apply a 30 Hz / ± 3V rectangular wave with a superimposed DC 3V voltage to the liquid crystal cell for 60 minutes at 60 ° C for 20 minutes. After 20 minutes, the DC 3 V is cut off and the residual voltage remaining in the liquid crystal cell is used. The optical scintillation method was used to determine the residual DC voltage of -18-(16) 200420982, which was 0V, and the residual DC voltage after 20 minutes was 0.55V. Then, a liquid crystal cell ion density measurement system (manufactured by Toyo Technology Co., Ltd., model name MTR-1) was applied to the liquid crystal cell with a voltage of a frequency of 0. 0 1 Hz and an amplitude of 丨 0ν. Based on the voltage of the liquid crystal cell, the resistance of the liquid crystal cell was measured, which was 4 6.6x 1 09Ω. (Comparative Example 1)

Using the liquid crystal alignment agent obtained in Preparation Example 2, a substrate with a liquid crystal alignment film was prepared as in Example 1. When the surface of the alignment film of the substrate with a liquid crystal alignment film was observed under a microscope, it was found that a liquid crystal alignment film having a non-destructive surface and no cloud-like defects (mirra) can be formed. A liquid crystal cell was produced in the same manner as in Example 1. A polarizing plate is placed above and below the liquid crystal cell, and a backlight is arranged under the liquid crystal cell. When the liquid crystal cell is rotated by 90 degrees, the light transmittance is changed to display light and dark, and it can be confirmed that the liquid crystal is indeed aligned.

A 30 Hz / ± 3 V rectangular wave with a superimposed DC 3 V voltage was applied to the liquid crystal cell for 60 minutes at 60 ° C. After 20 minutes, the DC 3 V was cut off and the residual voltage remaining in the liquid crystal cell was used. The 'residual DC voltage' measured by the optical scintillation elimination method was 0.12 V, and the residual DC voltage was 0.3 0 V after 20 minutes. Furthermore, a liquid crystal cell ion density measurement system (manufactured by Toyo Technology Co., Ltd., model name MTR_!) Was applied to the liquid crystal cell with a voltage of 0.0 1 Hz and an amplitude of 10 v. The current flowing through the liquid crystal cell and the liquid crystal cell were applied. The resistance of the liquid crystal cell was measured, and it was 2 [Oxi] 9 [Omega]. (Comparative Example 2)-19- (17) 200420982 The liquid crystal alignment agent 'obtained in Preparation Example 3 was used as in Example 1 to produce a substrate with a liquid crystal alignment film. When the surface of the alignment film of the substrate with the liquid crystal alignment film was observed under a microscope, it was found that a liquid crystal alignment film having a non-destructive surface and no cloud-like defects (mura) can be formed. A liquid crystal cell was produced in the same manner as in Example 1. The liquid crystal could not be aligned uniformly, and the transmittance did not change significantly when the liquid crystal cell was rotated at 90 degrees.

(Comparative Example 3)

The liquid crystal alignment agent obtained in Preparation Example 1 was spin-coated on a glass substrate with an electrode, and baked at a hot air circulation dryer at 2 0 ° C for 1 hour to obtain a polyimide film having a film thickness of 50 nm. . This coating film was subjected to a surface grinding treatment using a cloth cloth roller with a rotation number of 500 rpm, a traveling speed of 20 mm / sec, and a pushing amount of 0.6 mm 'to obtain a substrate with a liquid crystal alignment film. When the surface of the alignment film of the substrate with the liquid crystal alignment film was observed under a microscope, it was confirmed that there were tendon-like wounds during surface grinding. In order to measure the electrical properties of the liquid crystal cell, two such substrates were prepared, and a liquid crystal cell was produced in the same manner as in Example 1. A polarizing plate is placed above and below the liquid crystal cell, and a backlight is arranged below it. When the liquid crystal cell is rotated at 90 degrees, the light transmittance is changed to display light and dark, which can confirm that the liquid crystal is indeed aligned. Applying a 30 Hz / ± 3V rectangular wave 6 with a voltage of 3 V DC superimposed on the liquid crystal cell (maintained at rc for 20 minutes, and after 20 minutes, the DC 3 V is cut off, followed by the residual voltage remaining in the liquid crystal cell, As measured by the optical scintillation elimination method, the residual DC voltage immediately after was 0 V, and the residual DC voltage after 20 minutes was 0.00 V. Furthermore, a liquid crystal cell ion density measurement system (manufactured by Toyo Technology Co., Ltd., model name MTR- ]), Applying a voltage of 0.0 1 Hz with an amplitude of 1 OV to the liquid crystal cell -20- (18) 200420982, measuring the resistance of the liquid crystal cell from the current flowing through the liquid crystal cell and the voltage applied to the liquid crystal cell, which is 1 06 × 109Ω . Industrial possibilities

According to the present invention, a liquid crystal alignment film having a low charge accumulation when used as a liquid crystal display element can be formed in a manner excellent in workability and uniformity. In addition, a liquid crystal display element using the liquid crystal alignment film formed according to the present invention can continuously display an image with high contrast without causing superimposed images due to less charge accumulation. Furthermore, the present invention is a technology for improving the general versatility of electrical properties. It is not only mainly used in the latest display devices such as TFT liquid crystal display devices, VA, IPS liquid crystal display devices, etc., and can improve the image quality of all liquid crystal devices.

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Claims (1)

(1) 200420982 Patent application scope 1. A method for forming a liquid crystal alignment film, comprising: coating a substrate containing polyamine and soluble polyimide as a liquid crystal alignment agent on a substrate; a step of coating the substrate; The obtained coating film is irradiated with polarized ultraviolet rays, and then a liquid crystal alignment film is formed. 2. The method for forming a liquid crystal alignment film according to item 1 of the application, wherein the soluble polyfluorene imide is a soluble polyfluorene imide resin obtained by reacting a diacid anhydride having an alicyclic structure and a diamine. 3. The method for forming a liquid crystal alignment film according to item 1 or item 2 of the patent application scope, wherein the soluble polyfluorene imide contains the general formula (1) to represent a repeating unit (1) (In the formula, R 1 represents a divalent organic group.) 4 · The method for forming a liquid crystal alignment film according to any one of claims 1 to 3 of the patent application range ', wherein the polyamine includes a general formula (2) representing a repeating unit -22- HOOC COOH 200420982 (2) (wherein R2 represents a divalent organic group). 5. The method for forming a liquid crystal film of any one of claims 1 to 4 of the scope of application for a patent, wherein the weight ratio of the soluble polyfluorene / polyamine contained in the liquid crystal alignment agent is 0. 〇1 ~ 9 9.0 / 1. 6. The method for forming a liquid crystal alignment film according to any one of claims 1 to 5, in which the concentration of the soluble polyimide and polyimide contained in the liquid crystal alignment agent is 0.1 to 30% by weight . 7. The method for forming a liquid crystal alignment film according to any one of claims 1 to 6, in which the irradiation wavelength of polarized ultraviolet light is 150 to 400 nm, and the irradiation intensity is 1 to 60 J / cm2. 8. The method for forming a liquid crystal alignment film according to any one of claims 1 to 7, wherein the thickness of the coating film is 5 to 300 nm. -23-200420982 柒, (1), the designated representative of this case is: None. (2), a brief description of the representative symbols of the elements in this case: 捌, if there is a chemical formula in this case, please reveal the chemical formula that best shows the characteristics of the invention: