Low-emissivity afo semiconductor powder, preparation method thereof and infrared stealth coating

Abstract

The application provides a low-emissivity ATO semiconductor powder, a preparation method of the low-emissivity ATO semiconductor powder and an infrared stealth coating x Sn 1‑x O2, 0.01 The semiconductor material is used in an infrared stealth coating, and a low-emissivity stealth coating compatible with optical-infrared camouflage is obtained.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, specifically to a low emissivity ATO semiconductor powder, its preparation method, and an infrared stealth coating. Background Technology

[0002] Low emissivity materials, as the most important component of infrared stealth coatings, are one of the key research focuses and challenges. Currently, the main pigments used are metallic pigments, coloring pigments, and semiconductor pigments. Metallic pigments have high reflectivity, which is beneficial for reducing infrared emissivity, but increases the reflection of visible light, which is detrimental to visible light camouflage. Therefore, a large amount of coloring pigments needs to be added. The use of coloring pigments not only does not reduce the infrared emissivity of the coating, but also increases the emissivity of the coating. Semiconductor pigments, on the other hand, can have their infrared reflection spectrum controlled by doping, thus changing their emissivity. They also have a good foundation for multi-band camouflage compatibility, making them a promising type of pigment.

[0003] Antimony-doped tin oxide (ATO) semiconductor material is a new type of multifunctional impurity semiconductor material with advantages such as low resistance, chemical stability, wear resistance, and corrosion resistance. Its conductivity is between that of traditional semiconductors and metals, and it can be used as a low emissivity pigment in infrared stealth coatings.

[0004] There are many methods for preparing ATO nanoparticles, commonly including solid-phase, liquid-phase, and gas-phase methods. Liquid-phase methods include chemical coprecipitation, hydrothermal methods, and sol-gel methods, while gas-phase methods include vapor deposition, spraying, thermal evaporation, and sputtering. Solid-phase methods are rarely used due to drawbacks such as high energy consumption, irregular particle size, low conductivity, and susceptibility to impurities. While gas-phase methods can yield products with high purity, fine particle size, and good dispersibility, they require sophisticated equipment and are difficult to mass-produce. Currently, the most commonly used production method is chemical coprecipitation within the liquid-phase method. This method is simple, fast, and easily industrialized, but it requires repeated washing to remove residual impurity ions from the raw materials. Furthermore, the nucleation process in ATO semiconductor powder preparation via precipitation methods is generally controlled by adjusting factors such as reactant saturation, reaction temperature, and reaction time. This control is highly susceptible to factors such as mass and heat transfer during the reaction, making it difficult to effectively control the nucleation process. Summary of the Invention

[0005] To address the shortcomings of the aforementioned preparation methods, this invention provides a low-emissivity ATO semiconductor powder, its preparation method, and an infrared stealth coating. The ATO semiconductor powder of this invention exhibits a uniform particle size (25-60 nm) and good dispersibility. It possesses high purity while also exhibiting good conductivity and low emissivity. The emissivity in the mid-to-far infrared band (3-5 μm) can be adjusted by regulating Sb. 3+The doping level is controlled between 0.5 and 0.8; the far-infrared emissivity (8~12μm) can be adjusted by adjusting Sb. 3+ The doping concentration is controlled between 0.5 and 0.78. The preparation method involves first using a microemulsion method to perform an ultrasonic reaction at room temperature to obtain a uniform ATO semiconductor precursor precipitate with a narrow size distribution. The precipitate is then collected by high-speed centrifugation. Finally, the precursor is sintered in a muffle furnace to obtain an antimony-doped tin oxide (Sb). x Sn 1-x O2, 0.01 < x ≤ 0.5) low emissivity semiconductor powder; the low emissivity ATO semiconductor powder is used as a low emissivity filler in infrared stealth coating, which can effectively reduce the amount of pigment or dye used, and obtain a low emissivity coating that is compatible with optical-infrared camouflage.

[0006] The technical solution of this invention is as follows: First, a low emissivity ATO semiconductor powder with the chemical formula Sb is provided. x Sn 1-x O2, 0.01 < x ≤ 0.5; its particle size range is 25~60 nm; its emissivity in the far-infrared band of 3~5 μm is between 0.5 and 0.8; and its emissivity in the far-infrared band of 8~12 μm is between 0.5 and 0.78.

[0007] More importantly, the present invention provides a method for preparing the above-mentioned low emissivity ATO semiconductor powder, comprising the following steps:

[0008] S1, Preparation of metal ion salt solution: [The following text appears to be a separate, unrelated section:] Sn-containing... 4+ The salt reagent is added to deionized water to prepare Sn 4+ Salt solution, containing Sb 3+ Salt reagents are added to deionized water to prepare a salt solution;

[0009] S2. Preparation of precipitant solution: Weigh the precipitant and add it to deionized water to prepare a precipitant solution;

[0010] S3. Preparation of surfactant solution: The surfactant is added to an organic solvent to disperse and dissolve, thus preparing an organic surfactant solution;

[0011] S4. Measure 100-500 ml of the surfactant organic solution, then add Sn. 4+ Salt solution and Sb 3+ The salt solution was ultrasonically vibrated for 30 minutes to obtain the first microemulsion.

[0012] S5. Take the surfactant organic solution, add the precipitant solution, and sonicate for 30 minutes to obtain the second microemulsion.

[0013] S6. The first microemulsion and the second microemulsion are mixed together and ultrasonically reacted at room temperature. The precipitated product is collected by high-speed centrifugation, washed with deionized water, and dried to obtain the ATO semiconductor precursor. Finally, the precursor is placed in a muffle furnace for sintering to obtain low emissivity ATO semiconductor powder.

[0014] Furthermore, in step S1 above: Sn 4+ The salt reagent is tin chloride and / or sodium stannate; Sn 4+ The molar concentration of the salt solution is 0.1~1.0 mol / L; containing Sb 3+ The salt reagent is one or more of antimony nitrate, antimony chloride, and antimony acetate; Sb 3+ The molar concentration of the salt solution is 0.1~1.0 mol / L.

[0015] Furthermore, in step S2 above: the precipitant is one or more of sodium carbonate, sodium bicarbonate, ammonium bicarbonate, ammonium carbonate, ammonia, and urea; the molar concentration of the precipitant solution is 0.4~5.0 mol / L.

[0016] Furthermore, in step S3 above, the organic solvent is one or more of isooctane, n-octane, n-pentane, and cyclohexane.

[0017] Furthermore, in step S3 above, the surfactant is one of sodium di(2-ethylhexyl) succinate sulfonate, alkylolamide, alkylphenol polyoxyethylene ether, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate; the molar concentration of the surfactant organic solution is 0.05~0.2 mol / L.

[0018] Furthermore, in step S4 above: the surfactant organic solution: Sn 4+ Salt solution: Sb 3+ The volume ratio of the salt solution is 100~500: 2~10: 0.1~5; in step S5, the volume ratio of the surfactant organic solution to the precipitant solution is 100~500: 3.0~15.

[0019] In step S6: the ultrasonic reaction time is 30-60 min, the number of times the deionized water is rinsed is 2-3 times, and the sintering temperature is 400-600℃.

[0020] The present invention also provides an infrared stealth coating, the components of which include the following raw material components in parts by mass:

[0021] Film-forming substance: 30-40;

[0022] Low emissivity ATO semiconductor powder: 25-30;

[0023] Solvent: 25-35;

[0024] Pigment paste: 15-25;

[0025] Thickener: 2-5;

[0026] Dispersant: 1~2;

[0027] Defoamer: 1.5-2.

[0028] Furthermore, the film-forming substance is one of organosilicon-modified acrylic resin, polyurethane-modified acrylic resin, or alkyd resin; the solvent is one of anhydrous ethanol, acetone, or butyl acetate.

[0029] Furthermore, the aforementioned pigment paste is one or more of the following: ultramarine blue paste, 245 pigment red paste, permanent yellow paste, aniline black paste, and phthalocyanine green paste.

[0030] The method for preparing the above-mentioned infrared low emissivity coating into a coating includes the following steps:

[0031] Weigh out each component according to the mass ratio and set aside separately; add film-forming substance, solvent, ATO semiconductor powder, thickener and other additives to a container in sequence and disperse at high speed; then add color pastes of different colors according to the color matching principle to adjust to the camouflage color that meets the national military standard, and grind and disperse at high speed for 1 hour at 600~1200 r / min; adjust the viscosity to 20~25s, spray it on a tinplate, and bake at 120℃ for 20 minutes to obtain an infrared low emissivity coating compatible with optical camouflage.

[0032] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0033] 1. The low emissivity ATO semiconductor powder of the present invention has a uniform particle size (25~60nm) and good dispersibility. It possesses high purity while also exhibiting good conductivity and low emissivity. The emissivity in the mid-to-far infrared band (3~5μm) can be adjusted by adjusting Sb. 3+ The doping level is controlled between 0.5 and 0.8; the far-infrared emissivity (8~12μm) can be adjusted by adjusting Sb. 3+ The doping amount is controlled between 0.5 and 0.78.

[0034] 2. The low emissivity semiconductor powder preparation method provided by this invention is to prepare a low emissivity ATO semiconductor precursor through microemulsion. It only requires controlling the concentration of reactants, the amount of surfactant, and the amounts of water and organic solvent to form a microemulsion system to control the particle size within the water core. Once the particles within the water core grow to 20-30 nm, surfactant molecules will attach to the surface of the particles, stabilizing the particles and preventing them from growing further, thus obtaining a uniformly sized ATO semiconductor precursor. The process does not require repeated washing to remove impurity ions from the raw materials. The preparation method is simple, environmentally friendly, and the preparation conditions are mild, requiring no high temperature, high pressure, or complex and precise equipment, making it more suitable for industrial production. After calcination, ATO semiconductor materials with good dispersion performance, high purity, and low emissivity can be obtained.

[0035] 3. The low emissivity semiconductor powder of the present invention can be used as a component of infrared stealth coating, which can effectively reduce the amount of pigment or dye used, and obtain a low emissivity coating that is compatible with optical-infrared camouflage.

[0036] The low-emissivity semiconductor powder of this invention has good particle size, good dispersibility, high purity, excellent conductivity, and low infrared emissivity. Its preparation method is not only simple and environmentally friendly, but its application in infrared stealth coatings can effectively reduce the amount of pigments or dyes used, resulting in a low-emissivity coating that is compatible with optical-infrared camouflage. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0038] Figure 1 The images shown are scanning electron microscope (SEM) images of the ATO precursor and ATO semiconductor in Example 1.

[0039] Figure 2 This is a spectral reflectance diagram of the ATO semiconductor in the embodiment;

[0040] Figure 3 The images show the XRD patterns of the ATO precursor and ATO semiconductor in Example 1, where (a) is the XRD pattern of the ATO precursor and (b) is the XRD pattern of the ATO semiconductor. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, all medicines / reagents used are commercially available.

[0042] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings:

[0043] Implementation Case 1

[0044] 1. A method for preparing an ATO semiconductor pigment, comprising the following steps:

[0045] (1) Preparation of microemulsions

[0046] S1, Preparation of metal ion salt solution: [The following text appears to be a separate, unrelated section:] Sn-containing... 4+ The tin chloride reagent was added to deionized water to prepare a salt solution with a molar concentration of 0.1 mol / L. The solution containing Sb... 3+ The antimony nitrate reagent was added to deionized water to prepare a salt solution with a molar concentration of 0.1 mol / L, and the solution was prepared for use.

[0047] S2. Preparation of precipitant solution: Weigh 0.4 mol of sodium carbonate precipitant and add 1 L of deionized water to prepare a precipitant solution with a molar concentration of 0.4 mol / L. Set aside for use.

[0048] S3. Preparation of surfactant solution: Add 0.2 mol of sodium di(2-ethylhexyl) succinate surfactant to 1 L of isooctane solvent to disperse and dissolve, and prepare a surfactant organic solution with a molar concentration of 0.2 mol / L.

[0049] S4. Take 100 ml of a 0.2 mol / L isooctane solution containing the surfactant sodium di(2-ethylhexyl) succinate, and then add 2 ml of a 0.2 mol / L solution containing Sn. 4+ The solution and 0.5 ml of a 0.2 mol / L Sb-containing solution 3+ The solution was ultrasonically vibrated for 30 min to obtain microemulsion (A1); 100 ml of 0.2 mol / L isooctane solution containing the surfactant sodium di(2-ethylhexyl) succinate was added, and 3.0 ml of 0.4 mol / L sodium carbonate solution was ultrasonically vibrated for 30 min to obtain microemulsion (A2).

[0050] (2) Fabrication of ATO semiconductors

[0051] The ultrasonically dispersed A1 microemulsion and A2 microemulsion were mixed together and ultrasonically reacted at room temperature for 30 min. The precipitated product was collected by high-speed centrifugation, washed 2-3 times with deionized water, and the precipitate was dried to obtain the ATO semiconductor precursor. Finally, the precursor was placed in a muffle furnace and sintered at 500℃ to obtain antimony-doped tin oxide semiconductor pigment powder-1. The various performance parameters of the powder are shown in Table 1.

[0052] Depend on Figure 1 It can be seen that the diameter of the semiconductor precursor is 15~20nm, and the diameter of the ATO semiconductor is 25~30nm, neither of which shows obvious agglomeration, indicating that the product has good dispersion performance; Figure 3 It can be seen that the semiconductor precursor is amorphous and does not possess the obvious characteristic peaks of crystals. After high-temperature calcination, the diffraction peaks of the ATO semiconductor pigment and the tetragonal SnO2 phase correspond to each other, and no new diffraction peaks or other impurity peaks appear, indicating that the sample has a typical tetragonal rutile structure and high purity; Figure 2 It is known that the average reflectance of ATO semiconductor in the wavelength range of 350nm~950nm is 30.75%, which is not as high as that of metal powder. When applied to infrared stealth coatings, it can effectively reduce the amount of pigment or dye used and obtain a low emissivity coating that is compatible with optical-infrared camouflage.

[0053] 2. A method for preparing an infrared low emissivity coating, comprising the following steps:

[0054] Weigh out the following ingredients in a mass ratio of 30:25:15:5:2:25: silicone-modified acrylic resin, ATO semiconductor powder-1, aniline black and 245 pigment red paste (mass ratio 13:2), thickener, additives, and anhydrous ethanol solvent, and set aside separately. In a container, add the film-forming substance, solvent, ATO semiconductor powder, thickener, and additives sequentially and disperse at high speed. Then, according to the color matching principle, add aniline black and 245 pigment red paste to adjust to a camouflage color conforming to the national military standard – black BN1324. Grind and disperse at high speed at 800 r / min for 1 hour. Adjust the viscosity to 20-25 s, spray onto a tinplate, and bake at 120℃ for 20 minutes to obtain a black coating BN1324 with low infrared emissivity compatible with optical camouflage. The color coordinates and emissivity of the coating are shown in Table 2.

[0055] Implementation Case 2

[0056] 1. A method for preparing an ATO semiconductor pigment, comprising the following steps:

[0057] (1) Preparation of microemulsions

[0058] S1, Preparation of metal ion salt solution: [The following text appears to be a separate, unrelated section:] Sn-containing... 4+ Sodium stannate reagent was added to deionized water to prepare a salt solution with a molar concentration of 0.25 mol / L. The solution containing Sb... 3+ The antimony chloride reagent was added to deionized water to prepare a salt solution with a molar concentration of 0.25 mol / L, and the solution was prepared for use.

[0059] S2. Preparation of precipitant solution: Weigh 0.5 mol of precipitant and add 1 L of deionized water to prepare a precipitant solution with a molar concentration of 0.5 mol / L. Set aside for use.

[0060] S3. Preparation of surfactant solution: Add 0.3 mol of alkylphenol polyoxyethylene ether (TX-10) surfactant to 1 L of cyclohexane solvent to disperse and dissolve, and prepare a surfactant organic solution with a molar concentration of 0.3 mol / L. Set aside for use.

[0061] S4. Take 120 ml of a 0.3 mol / L cyclohexane solution containing the surfactant alkylphenol polyoxyethylene ether (TX-10), and then add 4 ml of a 0.25 mol / L Sn-containing solution. 4+ The solution and 0.5 ml of a 0.25 mol / L Sb-containing solution 3+ The solution was ultrasonically vibrated for 30 min to obtain microemulsion (A1); 120 ml of cyclohexane solution containing surfactant alkylphenol polyoxyethylene ether (TX-10) with a concentration of 0.2 mol / L was taken, and 6 ml of ammonium carbonate solution with a concentration of 0.5 mol / L was added and ultrasonically vibrated for 30 min to obtain microemulsion (A2).

[0062] (2) Fabrication of ATO semiconductors

[0063] The ultrasonically dispersed A1 microemulsion and A2 microemulsion were mixed together and ultrasonically reacted at room temperature for 30 min. The precipitate was collected by high-speed centrifugation, washed 2-3 times with deionized water, and the precipitate was dried to obtain the ATO semiconductor precursor. Finally, the precursor was placed in a muffle furnace and sintered at 550℃ to obtain antimony-doped tin oxide semiconductor pigment powder-2. The various performance parameters of the powder are shown in Table 1.

[0064] 2. A method for preparing an infrared low emissivity coating, comprising the following steps:

[0065] Weigh out polyurethane modified acrylic resin, ATO semiconductor powder-2, 245 pigment red paste, permanent yellow paste, aniline black paste (mass ratio 3:12:5), thickener, additives, and acetone solvent in a mass ratio of 32:28:20:4:2:24 and set aside separately. In a container, add the film-forming substance, solvent, ATO semiconductor powder, thickener, and additives sequentially and disperse at high speed. Then, add the three weighed color pastes to prepare a camouflage color, sand color SE2535, conforming to the national military standard. Grind and disperse at high speed at 800 r / min for 1 hour. Adjust the viscosity to 20-25 s, spray onto a tinplate, and bake at 120℃ for 20 minutes to obtain an infrared low-emissivity sand color coating SE2535 compatible with optical camouflage. The color coordinates and emissivity of the coating are shown in Table 2.

[0066] Implementation Case 3

[0067] 1. A method for preparing an ATO semiconductor pigment, comprising the following steps:

[0068] (1) Preparation of microemulsions

[0069] S1, Preparation of metal ion salt solution: [The following text appears to be a separate, unrelated section:] Sn-containing... 4+ The tin chloride reagent was added to deionized water to prepare a salt solution with a molar concentration of 1.0 mol / L. The solution containing Sb... 3+ The antimony chloride reagent was added to deionized water to prepare a salt solution with a molar concentration of 1.0 mol / L, and the solution was prepared for use.

[0070] S2. Preparation of precipitant solution: Weigh 2.0 mol of sodium carbonate precipitant and add 1 L of deionized water to prepare a sodium carbonate precipitant solution with a molar concentration of 2 mol / L. Set aside for use.

[0071] S3. Preparation of surfactant solution: Add 0.5 mol of sodium di(2-ethylhexyl) succinate surfactant to 1 L of n-octane solvent to disperse and dissolve, and prepare a surfactant organic solution with a molar concentration of 0.5 mol / L.

[0072] S4. Take 250 ml of a 0.5 mol / L solution of sodium di(2-ethylhexyl) succinate sulfonate in n-octane, and then add 10 ml of a 1 mol / L solution containing Sn. 4+ The solution and 0.5 ml of a 1 mol / L Sb-containing solution 3+The solution was ultrasonically vibrated for 30 min to obtain microemulsion (A1); 250 ml of a 0.5 mol / L solution of sodium di(2-ethylhexyl) succinate sulfonate in n-octane was added, and 15 ml of a 2 mol / L sodium carbonate solution was ultrasonically vibrated for 30 min to obtain microemulsion (A2).

[0073] (2) Fabrication of ATO semiconductors

[0074] The ultrasonically dispersed A1 microemulsion and A2 microemulsion were mixed together and ultrasonically reacted at room temperature for 30 min. The precipitate was collected by high-speed centrifugation, washed 2-3 times with deionized water, and dried to obtain the ATO semiconductor precursor. The scanning electron microscope image of the precursor is shown below. Figure 1 (a); Finally, the precursor is placed in a muffle furnace and sintered at 600°C to obtain antimony-doped tin oxide semiconductor pigment powder-3. The various performance parameters of the powder are shown in Table 1.

[0075] 2. A method for preparing an infrared low emissivity coating, comprising the following steps:

[0076] Weigh out alkyd resin, ATO semiconductor powder-3, 245 pigment red paste, permanent yellow paste, aniline black paste, phthalocyanine green paste (mass ratio 4:10:6:5), thickener, additives, and acetone solvent in a mass ratio of 40:30:25:2:3:30 and set aside separately. In a container, add the film-forming substance, solvent, ATO semiconductor powder, thickener, and additives sequentially and disperse at high speed. Then, add the four weighed pigments to adjust the color to a camouflage color DG0730 that meets the national military standard. Grind and disperse at 1000 r / min for 1 hour. Adjust the viscosity to 20-25 s, spray onto a tinplate, and bake at 120℃ for 20 minutes to obtain a dark green DG0730 with low infrared emissivity compatible with optical camouflage. The color coordinates and emissivity of the coating are shown in Table 2.

[0077] Table 1. Particle size distribution and emissivity of ATO semiconductors in the embodiments.

[0078]

[0079] Table 2 shows the color coordinates and emissivity of the infrared ultra-low emissivity coatings in the implementation cases.

[0080]

[0081] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A low emissivity ATO semiconductor powder, characterized in that, The particle size range of the ATO semiconductor powder is 40~60nm; its emissivity in the far-infrared band of 3~5μm is 0.576; and its emissivity in the far-infrared band of 8~12μm is 0.

548. The method for preparing the low emissivity ATO semiconductor powder includes the following steps: S1, Preparation of metal ion salt solution: [The following text appears to be a separate, unrelated section:] Sn-containing... 4+ The tin chloride reagent was added to deionized water to prepare a salt solution with a molar concentration of 1.0 mol / L. The solution containing Sb... 3+ The antimony chloride reagent was added to deionized water to prepare a salt solution with a molar concentration of 1.0 mol / L, and the solution was prepared for use. S2. Preparation of precipitant solution: Weigh 2.0 mol of sodium carbonate precipitant and add 1 L of deionized water to prepare a sodium carbonate precipitant solution with a molar concentration of 2 mol / L. Set aside for use. S3. Preparation of surfactant solution: Add 0.5 mol of sodium di(2-ethylhexyl) succinate surfactant to 1 L of n-octane solvent to disperse and dissolve, and prepare a surfactant organic solution with a molar concentration of 0.5 mol / L. S4. Take 250 ml of a 0.5 mol / L solution of sodium di(2-ethylhexyl) succinate sulfonate in n-octane, and then add 10 ml of a 1 mol / L solution containing Sn. 4+ The solution and 0.5 ml of a 1 mol / L Sb-containing solution 3+ The solution was ultrasonically vibrated for 30 min to obtain microemulsion A1; 250 ml of a 0.5 mol / L solution of sodium di(2-ethylhexyl) succinate sulfonate containing surfactant in n-octane was taken, and 15 ml of a 2 mol / L sodium carbonate solution was added and ultrasonically vibrated for 30 min to obtain microemulsion A2. The ultrasonically dispersed microemulsions A1 and A2 were mixed together and ultrasonically reacted at room temperature for 30 minutes. The precipitated product was collected by high-speed centrifugation, washed 2-3 times with deionized water, and the precipitate was dried to obtain the ATO semiconductor precursor. Finally, the precursor was placed in a muffle furnace and sintered at 600°C to obtain low emissivity ATO semiconductor powder.

2. An infrared stealth coating, characterized in that, The low emissivity ATO semiconductor powder of claim 1 comprises the following raw material components in parts by mass: Alkyd resin: 40; Low emissivity ATO semiconductor powder: 30; Acetone solvent: 30; Pigment paste: 25; Thickener: 2; Additives: 3; The pigment paste is prepared by mixing 245 pigment red paste, permanent yellow paste, aniline black paste and phthalocyanine green paste in a mass ratio of 4:10:6:5.

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