KR20010066314A - Anionic electrodeposition coating composition for forming pixels of liquid crystal display, and its uses - Google Patents

Abstract

PURPOSE: An anionic electrodepositing paint composition is provided, which shortens the manufacturing time and improves yield without affecting high permeability, heat-proof property, chemical-resistance and liquid crystal pixel. And a using method thereof is also provided. CONSTITUTION: The anionic electrodepositing paint composition comprises: (i) 10-15 wt.% of an acrylate copolymer which has a number average molecular weight of 3,000-300,000 and a dielectric constant of 3.0-6.0 in a dried film of paint thickness of 1-2.5 micrometer; (ii) 1-5 wt.% of a paint which is selected from anthraquinone paint and phthalocyanine paint and has an average particle diameter of 20-150 nanometers; (iii) 1-3 wt.% of a melamine typed hardening agent for electrodeposition; (iv) 1-5 wt.% of an organic solvent; (v) 0.5-1 mol of amine per 1 mol of carboxyl group; and (vi) the remaining amount of distilled water. In the composition, the acrylate copolymer is prepared by reacting: (a) 0.5-30 wt.% of a carboxylic acid which is selected from the group consisting of acrylic acid, methacrylic acid and maleic acid; (b) 0.5-30 wt.% of a reaction product which is represented by the formula (1) and prepared by reacting a glycidyl acrylate or a glycidyl methacylate with a quaternary ammonium salt; (c) 10-40 wt.% of a monomer which has at least one hydroxy group and is selected from the group consisting of C2-5 hydroxy alkyl acrylate and C2-5 hydroxy alkyl methacrylate; and (d) 10-70 wt.% of at least one unsaturated monomer which is selected from the group consisting of C2-5 alkyl acrylate and C2-5 alkyl methacrylate. In the formula (1), each R1 and R2 is hydrogen or C1-2 alkyl group; R3 is C1-2 alkyl group or hydroxy alkyl group, and R4 is C1-3 alkanoate. The cationic electrodepositing paint composition is used for directly forming pixels on a transparent electrode layer of a thin film transistor base plate by using an electrodeposition method of impressing 3-100 direct current voltage for 3-300 seconds thereon.

Description

Anionic electrodeposition coating composition for forming pixels of liquid crystal display, and its uses}

The present invention relates to an anion electrodeposition coating composition for forming a liquid crystal display pixel and a method of using the same. More specifically, the number average molecular weight is 3,000 to 30,000, and has a dielectric constant of 3.0 to 6.0 at a dry film thickness of 1 to 2.5 μm. The present invention relates to an anion electrodeposition coating composition comprising an acrylate copolymer and a method for use in forming a pixel for a color display in which a pixel is directly formed on a transparent electrode layer of a TFT substrate using an electrodeposition method.

Due to the recent development of the multimedia industry, the use of liquid crystal displays is rapidly increasing, and color filters commonly used in liquid crystal displays are manufactured by pigment dispersion, dyeing, printing, electrodeposition, film transfer, and the like. Among them, the pigment dispersion method is mainly used because of the advantages of excellent reproducibility and elaboration of the process and easy manufacturing.

An example of applying the pigment dispersion method is described in Japanese Patent Application Laid-Open No. 60-129739, which describes a photolithography technique that has a level of resolution applicable to TFT-LCD and is applied to remove the limitation of pattern formation. In addition, Japanese Patent Application Laid-Open No. 60-237403 discloses a pixel formation mainly composed of a photosensitive resin and a pigment and a method of forming a black matrix between each pixel, as well as US Patent Publication Nos. 5,085,973 and 4,786,148. Arcs.

However, the conventional pigment dispersion method uses three masks as shown in FIG. 1 to form a pixel, which increases the probability of misalignment and prolongs the process time, and thus the process yield. There is a declining problem. In addition, because the spin coating method (Spin Coating Method) is applied, the consumption of materials and equipment investment costs are high.

In addition, the electrodeposition method requires only one photolithography process, and has an advantage of excellent smoothness of the pixel surface, and the application thereof has recently increased. For example, the synthesis of acrylate copolymers having improved dispersibility by introducing N-vinyl-2-pyrrolidone as a pigment dispersing functional group and coating compositions thereof are described in US Pat. No. 5,523,340, with maleinated linseed oil The synthesis of half-ester compounds of polybutadiene and 2-hydroxyethyl acrylate and their coating compositions are described in US Pat. No. 5,573,876. These compositions have a disadvantage in that a separate filtration process is required due to insufficient dispersibility of the pigment, and it is difficult to secure the reproducibility, and since there is no conductivity of the coating film, one more transparent electrode layer for driving is formed on the pixel, resulting in low light transmittance. There are disadvantages.

In general, the electrodeposition color filter has a three-layer structure consisting of an electroconductive layer (ITO layer), a color pixel, and an electroconductive layer (ITO layer). Because. As such, the formation of one more ITO layer not only complicates the process but also has the disadvantage that the transmittance of the final pixel is lowered.

In order to solve the above problems, the present inventors have studied and found that when the electrodeposition method is used, the electrodeposition coating composition containing the quaternary ammonium salt can be used to increase the dielectric constant of the resin to solve the problem. The present invention has been completed based on this.

Accordingly, it is an object of the present invention to provide an anionic electrodeposition coating composition which does not affect high permeability, heat resistance, chemical resistance, and liquid crystal pixels, and can shorten processing time and improve yield.

Another object of the present invention is to provide a method of using the anionic electrodeposition coating composition.

Anion electrodeposition coating composition for forming a liquid crystal display pixel of the present invention for achieving the above object, in the electrodeposition coating composition, 0.5 to 30% by weight of a carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, maleic acid; 0.5 to 30% by weight of a reactant of glycidyl acrylate or glycidyl methacrylate, and a quaternary ammonium salt represented by Formula 1 below; 10 to 40% by weight of a monomer containing at least one hydroxyl group selected from the group consisting of hydroxy alkyl acrylates and hydroxy alkyl methacrylates having 2 to 5 carbon atoms; And from 10 to 70% by weight of at least one unsaturated monomer selected from the group consisting of alkyl acrylates and alkyl methacrylates having 2 to 5 carbon atoms at 60 to 120 ° C., a number average molecular weight of 3,000 to 30,000, 1-2.5 10-15% by weight of an acrylate copolymer having a dielectric constant of 3.0-6.0 at a dry coating thickness of 탆;

1 to 5 wt% of an average particle diameter of 20 to 150 nm selected from anthraquinone pigments and phthalocyanine pigments;

1-3% by weight of an electrodeposition melamine type curing agent;

1 to 5% by weight of organic solvent;

0.5-1 mol of amines per mol of carboxyl groups; And

Consisting of the remaining distilled water.

Here, R <_1> , R <_2> is H or a C1-C2 alkyl group, R <_3> is a C1-C2 alkyl group or a hydroxyalkyl group, and R <_4> is a C1-C3 alkanoate.

In addition, the method of using an anion electrodeposition coating composition for achieving another object of the present invention, by using the electrodeposition method applied for 3 to 300 seconds at a DC voltage of 3 to 100V to form a pixel directly on the transparent electrode layer of the TFT substrate. It consists of the method of using the said composition at the time of forming the pixel for color displays.

1 is a manufacturing process chart of a color filter using a conventional pigment dispersion method,

2 is an electrodeposition process chart using the electrodeposition coating composition according to the present invention;

Figure 3 is a graph showing the spectral characteristics of each of the red, green, blue pixels produced in accordance with the present invention.

-Explanation of symbols for the main parts of the drawing-

1. black matrix 2. TFT substrate or glass substrate

3. Pigment Dispersion Resist Layer 4. Photomask

5. Transparent Electrode Layer

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

As described above, the electrodeposition coating composition of the present invention has an number average molecular weight of 3,000 to 30,000, an acrylate copolymer having a dielectric constant of 3.0-6.0 at a thickness of a dry coating film of 1-2.5 μm, a pigment, a curing agent, and an organic solvent. , Amines and distilled water.

Therefore, in the present invention, if the dielectric constant of the resin is increased by introducing a quaternary ammonium salt into the electrodeposition coating composition, unlike a pixel having a conventional polymer composition (the normal polymer has a dielectric constant of 2.5 or less), it does not affect driving of the liquid crystal. An additional process for forming a transparent electrode for driving a liquid crystal becomes unnecessary. Therefore, in the present invention, the electrical properties (dielectric constant and thickness of the dry coating film) are controlled by preparing an acrylate copolymer incorporating a quaternary ammonium salt.

The acrylate copolymer of the present invention is 0.5 to 30% by weight of carboxylic acid; 0.5 to 30% by weight of a reactant of glycidyl acrylate or glycidyl methacrylate, and a quaternary ammonium salt represented by Formula 1 below;

Formula 1

Wherein R ₁ and R ₂ are H or an alkyl group having _{1 to 2} carbon atoms, R ₃ is an alkyl group or hydroxyalkyl group having 1 to ₂ carbon atoms, and R ₄ is an alkanoate having 1 to 3 carbon atoms; 10 to 40% by weight of a monomer containing at least one hydroxyl group selected from the group consisting of hydroxy alkyl acrylates and hydroxy alkyl methacrylates having 2 to 5 carbon atoms; And 10 to 70% by weight of at least one unsaturated monomer selected from the group consisting of alkyl acrylates and alkyl methacrylates having 2 to 5 carbon atoms at 60 to 120 ° C., and the prepared acrylate copolymer is 3,000 to 30,000. It has a number average molecular weight of and has a dielectric constant of 3.0-6.0 at a thickness of the dry coating film of 1-2.5㎛.

Here, if the number average molecular weight of the acrylate copolymer is less than 3,000, the strength of the coating film after curing is easy to be damaged during the further process, and if it exceeds 30,000, the smoothness of the pixel coating film is deteriorated, and the thickness of the dry coating film is 1 If it is less than μm, it is difficult to control the color strength, and if it exceeds 2.5 μm, it is difficult to secure an appropriate transmittance. If the dielectric constant is less than 3.0, desired conductivity cannot be obtained.

The carboxylic acid is selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, etc., when the amount of use is less than 0.5% by weight, the water dispersibility is poor, and the aggregation of pigment particles occurs. The consumption will increase.

In addition, the reactants of the glycidyl acrylate or glycidyl methacrylate of the formula (1), and the quaternary ammonium salts have excellent affinity for organic pigments having hydrophobicity, so that the pigment particles are reaggregated by dispersing the pigment particles in a unique primary particle size. It has a functional group that can prevent the phenomenon, and if the amount is less than 0.5% by weight, it does not show the proper dispersibility necessary to secure a high transmittance, and when it exceeds 30% by weight, the viscosity of the resin increases to increase the time spent in dispersing the pigment. do.

Moreover, as a monomer containing at least one hydroxyl group selected from the group which consists of said C2-C5 hydroxy alkyl acrylate and hydroxy alkyl methacrylate, 2-hydroxyethyl acrylate and 2-hydroxyethyl meta Acrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, and when the amount is less than 10% by weight, there is less crosslinking site with melamine curing agent. Hardening strength falls, and if it exceeds 40% by weight, it is difficult to secure proper dispersibility.

Examples of the at least one unsaturated monomer selected from the group consisting of alkyl acrylates and alkyl methacrylates having 2 to 5 carbon atoms include ethyl acrylate, propyl acrylate, methyl methacrylate and butyl acrylate. If it is less than 10% by weight, the hardness of the coating film is increased to cause cracking, and if it exceeds 70% by weight, the surface sticky of the coating film is increased, so that foreign matter adhesion is increased.

In addition, if the reaction temperature for producing the acrylate copolymer is less than 60 ℃ is less reactive, the content of the unreacted monomer increases, if it exceeds 120 ℃ it is not possible to obtain the desired molecular weight.

In order to impart the color of the pixel, the pigment used in the anionic electrodeposition paint composition of the present invention is selected from an anthraquinone pigment and a phthalocyanine pigment, for example, an anthraquinone pigment color (CI Number) red 147, red 168, red 177, blue 60 and the like, phthalocyanine-based colored pigment number green 7, green 36, blue 15: 2, blue 15: 3, blue 15: 6, etc. Sulfur 110, sulfur 139, ruler 36 and the like can be used in combination. The average particle diameter of the pigments is 20-150nm, preferably 10-100nm, if the average particle diameter is less than 20nm, it is difficult to disperse the pigment and re-agglomerate even after dispersion, if it exceeds 150nm to secure a high transmittance of the pixel Becomes impossible. In addition, the amount of the pigment is preferably used 1 to 5% by weight, if the amount is less than 1% by weight it is difficult to secure the minimum required level of color concentration, when it exceeds 5% by weight it is difficult to secure a high transmittance and the dispersion stability is poor .

In addition, the curing agent used to satisfy the chemical resistance to the solvents used in the patterning process of the pixel electrode, Cymel 303, a general-purpose curing agent mainly composed of hexamethoxymethylmelamine (HMMM) And melamine-type modified curing agents for electrodeposition excellent in electrophoresis, such as Cymel 1116, Cymel 1123, Cymel 1130, Cymel 1156, and the like. In addition, the amount of the curing agent used is preferably 1 to 3% by weight. If the amount of the curing agent is less than 1% by weight, it is difficult to secure appropriate curing strength.

The organic solvent used to control the viscosity and curing behavior of the compositions is selected from the group consisting of butyl cellosolve, butoxyethyl acetate, 1-methoxy-2-propanol and methyl ethyl ketone, the organic solvents being water and Has compatibility. In addition, the amount of the organic solvent is preferably used in an amount of 1 to 5% by weight. If the amount is less than 1% by weight, the viscosity of the initial dispersion increases, so that the dispersion time is long, and when the amount exceeds 5% by weight, the thickness of the coating film increases. The optical characteristic is lowered.

In addition, distilled water from which metal ions and other miscellaneous ions are removed must be used as the diluent.

In addition, an organic amine must be added to neutralize the carboxyl group of the electrodeposition resin and solubilize it in water as a diluent. As the amine used in the present invention, a tertiary amine having a high boiling point in terms of storage stability of the electrodeposition resin composition is preferable, for example, triethylamine, tripropylamine, tributylamine, triethanolamine, tripropanolamine and tri An amine selected from the group consisting of butanolamine is preferable, and the amount of addition may be changed depending on the number of moles of the carboxyl groups contained in the resin. Generally, 0.5 to 1 mole of the amine should be added per mole of the carboxyl groups. If less than 0.5 moles of amine is added, the degree of ionization of the resin is insufficient, resulting in poor dispersibility in water, and when more than 1.0 moles of amine is added, storage stability becomes poor.

. The main components of indium of an ITO layer of tin oxide when being oxidized by the acid during the electrodeposition process, a neutralizing agent is acid cation electrodeposition is applied is not possible, and neutralizing the carboxylic acid (COOH) which is introduced into the resin with an amine COO ^- ion This forms an anion and becomes soluble in water.

If necessary, additives necessary for improving physical properties such as an antifoaming agent, a smoothing agent, and a dispersing agent may be used in combination.

The electrodeposition coating composition requires a dispersing device that exerts a physical impact because it must be dispersed in the primary particle size of the pigment after mixing to ensure high transmittance. The choice of disperser depends on the properties and dispersibility of the resin, including commercially available ball mills, sand mills, attritors, and the like. Dispersion time should be set repeatedly to check the particle size and set the optimum time required. After the dispersion is completed, the dispersed particles have an average particle size in the range of 50-200 nm, and have a variation of about 10-50 nm for each color of the pigment. If the dispersed particle size exceeds 200 nm, not only high transmittance of more than 90% can be secured, but also the electrodeposition surface becomes uneven and the long-term storage stability is poor.

In the anion electrodeposition coating composition according to the present invention, a transparent electrode layer 5 is formed after forming a black matrix on a substrate as shown in FIG. 2 by using an electrodeposition method applied for 3 to 300 seconds at a DC voltage of 3 to 100V. And a method of sequentially forming green and blue pixels after red filter electrodeposition, and used in forming a color display pixel which directly forms a pixel on a transparent electrode layer of a TFT substrate, and the transparent electrode layer is an ITO layer (indium tin oxide). A layer is mentioned.

For example, the electrodeposition method according to the present invention may be carried out by placing a glass substrate on which a conductive transparent material is deposited into a prepared electrodeposition tank, applying an electric conductive circuit formed on the substrate to a cathode, a stainless substrate as a cathode, and then applying a DC voltage. .

In addition, as described above, the electrodeposition voltage should be set to the minimum voltage corresponding to the minimum thickness of the pixel satisfying the high transmittance and color reproducibility, depending greatly on the design of the resin. Generally, electrodeposition is performed by applying for 3 to 300 seconds at a DC voltage of 3 to 100V, preferably 5 to 300 seconds at 5 to 100V.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

Example 1

Into a four-necked reactor, 89.1 g of dimethylethanolamine is charged and heated to 60 ° C. under a nitrogen atmosphere. 60 g of acetic acid is added to the reactor while maintaining the temperature. After maintaining the temperature at 85 ° C. for 1 hour, 284.3 g of glycidyl methacrylate was added dropwise into the reactor for 2 hours. After completion of dropping, the reaction product of the glycidyl methacrylate and the quaternary ammonium salt (pigment dispersant-containing monomer 1) was prepared by measuring the residual epoxy equivalent while maintaining the temperature for 3 hours to confirm the completion of the reaction.

In addition, 100 g of butyl cellosolve is added to a four-necked reactor and heated up to 90 ° C. under a nitrogen atmosphere. The mixture of Table 1 was added dropwise to the reactor for 3 hours while maintaining the temperature.

ingredient g Methacrylic acid 9.1 Pigment Dispersion-containing Monomer 1 12.0 Methyl methacrylate 24.3 Ethyl acrylate 30.3 2-hydroxyethyl acrylate 24.3 N, N'-azobisisobutylonitrile (acrylic polymerization initiator) 2

After completion of the dropping, it was confirmed by measuring the solids content after the completion of the reaction that the remaining unreacted product was not present while maintaining the reaction for 4 hours. The molecular weight of the acrylate copolymer (electrodeposit 1) obtained in this way was 25,000 when measured by GPC.

The acrylate copolymer thus prepared was mixed in a 2000 ml container with the components shown in Table 2 below and stirred at high speed for 2 hours. 300 g of distilled water was slowly added to the vessel while stirring, followed by high speed stirring for 1 hour. 500 g of glass beads are then added and the container is sealed and dispersed for 4 hours using a red devil miller. After completion of the dispersion, distilled water is slowly added while stirring to adjust the solid content concentration of the electrodeposition resin composition to 10%.

ingredient Enemy (g) Rust (g) Blue (g) Electrodeposition Resin 1 300.0 300.0 300.0 ¹⁾ Chromophthalic A3B 50.0 ²⁾ Hostta Perm Rust 8G 50.0 ³⁾ Host Star Firm AFL 20.0 ⁴⁾ Igapor Sulfur 2R-CF 20.0 20.0 ⁵⁾ Host Pump RL-NF 10.0 Butyl Cellosolve 50.0 50.0 50.0 Cymel 1130 52.0 52.0 52.0 ⁶⁾ triethanolamine 14.0 14.0 14.0

1), 4) Ciba Specialty Corporation

2), 3), 5) Hoechst Co., Ltd.

6) Showa Chemical Corporation

After the ITO layer was chemically deposited on the prepared electrode solution, the substrate (10cm × 10cm) on which the patterned pixel electrode was formed was used as an anode, and the same size stainless steel plate was used as the cathode. The temperature is adjusted to 25 ° C.

Electrodeposition was performed by applying an electrodeposition voltage of 2 to 30V for 5 to 300 seconds to form a pixel thin film having a thickness of 1 to 2.5 microns. After electrodeposition is complete, the substrate is washed with distilled water to remove unremained electrodeposited material and, if necessary, dried with nitrogen. Subsequently, electrodeposition was repeated for the remaining colors (red, green, and blue independence) in the same manner. After completing the formation of the tricolor pixel thin film as shown in FIG. Measurement results of the physical properties of the completed pixel thin film are shown in Table 5 below, and the transmittance is as shown in FIG. 3.

Example 2

Using 117.19 g of diethylethanolamine, a reaction product of glycidyl methacrylate and a quaternary ammonium salt (pigment dispersant-containing monomer 2) was prepared, and an acrylate copolymer (electrodeposition) having a molecular weight of 27,000 as a component of Table 3 below. A resin film 2 was prepared in the same manner as in Example 1, except that resin 2) was used, and the measurement results of the physical properties of the completed pixel film were shown in Table 5 below.

ingredient g Methacrylic acid 9.1 Pigment Disperser-containing Monomer 2 16.0 Methyl methacrylate 22.3 Ethyl acrylate 28.3 2-hydroxyethyl acrylate 24.3 N, N'-azobisisobutylonitrile 2

Comparative Example 1

73.14 g of diethylamine was added to a four-necked reactor and the temperature was raised to 105 ° C. under a nitrogen atmosphere. 284.3 g of glycidyl methacrylate was added dropwise into the reactor for 2 hours while maintaining the temperature. After completion of dropping, maintaining the temperature for 3 hours to determine the completion of the reaction by measuring the residual epoxy equivalent to prepare a monomer 3, and mixed with the components of Table 4 to the acrylate copolymer having a molecular weight of 25,000 (electrodeposited resin 3) A thin film was manufactured in the same manner as in Example 1 except for preparing the same and using the same, and the measurement results of the physical properties of the completed pixel thin film are shown in Table 5 below.

ingredient g Methacrylic acid 9.1 Monomer 3 12.0 Methyl methacrylate 24.3 Ethyl acrylate 30.3 2-hydroxyethyl acrylate 24.3 N, N'-azobisisobutylonitrile 2

Pixel color Electrodeposition conditions Pixel thin film thickness (㎛) Transmittance (%) permittivity Example 1 enemy 7 V, 60 seconds 1.78 90.6 5.8 rust 7 V, 90 seconds 1.68 85.8 5.6 blue 6.5 V, 90 seconds 1.52 83.0 5.2 Example 2 enemy 8 V, 60 seconds 1.59 83.5 5.3 rust 8 V, 75 seconds 1.92 84.6 4.9 blue 8 V, 45 seconds 1.54 67.2 5.1 Comparative Example 1 enemy 8.5 V, 60 seconds 1.83 87.5 3.1 rust 8.5 V, 75 seconds 1.24 83.8 2.8 blue 8 V, 60 seconds 1.62 72.2 2.9

3 shows high transmittance and peak consistency of green, red, and blue. As a result of evaluation of the heat resistance of the thin film, no change in mass and appearance is observed even after sintering at 200 ° C. for 4 hours, and the organic solvent used in the manufacturing process The results of the deposition experiments were also the same. Therefore, it can be seen that as a result of the analysis, high permeability, heat resistance, chemical resistance, and proper dielectric constant of 4 to 6 can be obtained without affecting the liquid crystal pixel, and shortening the processing time and improving the yield.

As can be seen from the above examples and comparative examples, by using the composition according to the present invention incorporating the quaternary ammonium salt directly on the substrate by electrodeposition, it does not affect the high permeability, heat resistance, chemical resistance, and liquid crystal pixels. Can shorten the process time and improve the yield.

Claims (7)

In the electrodeposition coating composition, 0.5 to 30% by weight of a carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, and the like; 0.5 to 30% by weight of a reactant of glycidyl acrylate or glycidyl methacrylate, and a quaternary ammonium salt represented by Formula 1 below; 10 to 40% by weight of a monomer containing at least one hydroxyl group selected from the group consisting of hydroxy alkyl acrylates and hydroxy alkyl methacrylates having 2 to 5 carbon atoms; And from 10 to 70% by weight of at least one unsaturated monomer selected from the group consisting of alkyl acrylates and alkyl methacrylates having 2 to 5 carbon atoms at 60 to 120 ° C., a number average molecular weight of 3,000 to 30,000, 1-2.5 10-15% by weight of an acrylate copolymer having a dielectric constant of 3.0-6.0 at a dry coating thickness of 탆; 1 to 5 wt% of an average particle diameter of 20 to 150 nm selected from anthraquinone pigments and phthalocyanine pigments; 1-3% by weight of an electrodeposition melamine type curing agent; 1 to 5% by weight of organic solvent; 0.5-1 mol of amines per mol of carboxyl groups; And Anion electrodeposition coating composition for forming a liquid crystal display pixel containing the remaining distilled water. Formula 1 Here, R <_1> , R <_2> is H or a C1-C2 alkyl group, R <_3> is a C1-C2 alkyl group or a hydroxyalkyl group, and R <_4> is a C1-C3 alkanoate. The anthraquinone pigments of claim 1, wherein the pigments are colored pigments red 147, red 168, red 177 and blue 60, and pigments green 7, green 36, blue 15: 2, and blue 15: 3. And a phthalocyanine-based pigment composed of blue 15: 6. Anion electrodeposition coating composition for forming a liquid crystal display pixel. 2. The anion electrodeposition paint for forming a liquid crystal display pixel according to claim 1, wherein the curing agent is selected from cymel 303, a general-purpose curing agent, and cymels 1116, 1123, 1130, and 1156, a modified melamine type curing agent for electrodeposition. Composition. The liquid crystal of claim 1, wherein the organic solvent is an organic solvent having compatibility with water selected from the group consisting of butyl cellosolve, butoxyethyl acetate, 1-methoxy-2-propanol, and methyl ethyl ketone. Anion electrodeposition coating composition for display pixel formation. The anion electrodeposition coating composition for forming a liquid crystal display pixel according to claim 1, wherein the amine is selected from the group consisting of triethylamine, tripropylamine, tributylamine, triethanolamine, tripropanolamine and tributanolamine. An anion electrodeposition coating composition according to the above-described method is used to form a pixel for color display, in which a pixel is directly formed on a transparent electrode layer of a TFT substrate using an electrodeposition method applied for 3 to 300 seconds at a DC voltage of 3 to 100 V. How to use. 7. The method according to claim 6, wherein the transparent electrode layer is an ITO layer.