Carbon-doped pearlescent pigment and preparation method thereof
By covering the surface of the pearlescent pigment base material with metal oxide layer formed by organometallic salt and carbon doping, the problem of white color and low saturation of pearlescent pigment preparation of liquid phase deposition is solved, and the preparation of pearlescent pigment with high saturation is achieved, reducing equipment cost and energy consumption.
Patent Information
- Application Number
- CN202510406288.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-02
- Publication Date
- 2025-07-04
AI Technical Summary
When the existing pearlescent pigments are prepared by liquid deposition, there are problems such as white color and low saturation. The preparation of high saturation pearlescent pigments requires vapor deposition equipment, which is expensive.
Organometallic salt is used as the precursor of the metal oxide film, and the metal oxide layer is coated on the surface of the substrate, and the organic components are carbonized by isolated air calcination to form carbon-doped pearled pigments, which improves absorbance and enhances color saturation.
The preparation of high-saturation pearlescent pigments by liquid phase deposition method is achieved, which is characterized by easy access to raw materials, simple operation, environmentally friendly, low equipment cost and high color saturation.
Smart Images
Figure CN120248660A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of pigments. Specifically, it relates to a carbon-doped pearlescent pigment and a preparation method thereof. Technical Background
[0002] Pearlescent pigments generally refer to pigments with a pearl luster. Because they often exhibit a certain metallic luster, they are also called non-metallic pigments with metallic luster. Analyzing the characteristics of the crystal structures of these pigments, it is found that they are all flaky structures and have a high reflectivity. When irradiated with ordinary white light, they can produce multi-level reflections and interference effects, thus presenting soft and rich colors.
[0003] Currently, the existing synthetic pearlescent pigments are generally prepared by wet chemical methods on the surface of flaky substrates, depositing and coating one or more layers of hydrated metal oxides, such as titanium dioxide, iron(III) oxide, tin dioxide, etc., or their compounds, such as iron titanate, and then obtaining the pearlescent pigments through filtration, washing, drying, and calcination. The substrates are generally wet-ground natural muscovite and phlogopite, synthetic mica, glass flakes, and alumina flakes. Synthetic pearlescent pigments can generally be divided into titanium dioxide series, iron oxide series, and gold series products. At the same time, according to the different thicknesses of the oxides coated on the substrate surface, different light interference colors are formed, forming various interference color pearlescent pigments, which can generally be divided into silver-white, gold, orange-red, red, purple, blue, cyan, and green.
[0004] Since the existing pearlescent pigments prepared by the liquid-phase deposition method all have the problems of the powder samples being white in color and having low saturation, the application range of the pearlescent pigments prepared by this method is limited; and most of the high-saturation pearlescent pigments currently available on the market are prepared by the vapor-phase deposition method, which requires specific vapor-phase deposition equipment and is expensive. Therefore, it is necessary to study a preparation method for preparing high-saturation pearlescent pigments by the liquid-phase deposition method. Summary of the Invention
[0005] The present invention provides a carbon-doped pearlescent pigment and a preparation method thereof. Using an organometallic salt as the precursor of the metal oxide film, a metal oxide film is coated on the surface of the substrate. Since the precursor is an organometallic salt, there are organic components in the metal oxide layer after coating. After calcination in an air-free environment, the organic components in the metal oxide layer are carbonized to obtain carbon doping. Carbon doping can improve the absorbance of the pearlescent pigment and reduce the light transmission, thereby realizing the preparation of high-saturation pearlescent pigments by the liquid-phase deposition method, which has the characteristics of safe and easily available raw materials, simple and safe operation, environmental friendliness, low equipment cost and energy consumption, strong scintillation, and high color saturation.
[0006] A carbon-doped pearlescent pigment provided by the present invention comprises a substrate, a metal oxide layer coated on the substrate, and carbon doped in the metal oxide layer.
[0007] The thickness of the pearlescent pigment substrate is between 0.1 - 2 μm, and the thickness of the metal oxide layer is between 100 - 500 nm; the doping amount of the carbon accounts for 10 - 30 wt% of the total amount of the pearlescent pigment.
[0008] The substrate is a substrate sheet, and the substrate sheet is natural mica, synthetic mica, glass flake or alumina thin sheet.
[0009] The metal oxide is one or several of titanium dioxide, iron(III) oxide, zirconium dioxide, tin dioxide, iron titanate, silicon dioxide, chromium(III) oxide, cobalt oxide, zirconium silicate, zirconium hydroxide, aluminum oxide.
[0010] The carbon doping is obtained by calcining the organic component in the organometallic salt under an air-insulated atmosphere.
[0011] A preparation method of a carbon-doped pearlescent pigment comprises the following steps: (1) Mix the substrate with hydrochloric acid solution, soak for a period of time, and clean the surface of the substrate; (2) Mix the substrate with an appropriate amount of organic solvent, stir to form a slurry; (3) Add an organometallic salt solution, adjust the pH to its hydrolysis range, carry out a hydrolysis reaction, and coat a metal oxide layer on the surface of the substrate; (4) Carry out calcination under air insulation to obtain carbon doping.
[0012] It further includes the step of adjusting the temperature and pH value of the solution.
[0013] The temperature of the solution is adjusted to -20°C - 60°C, and the pH value is 3 - 10.
[0014] In the step (1), the synthetic mica substrate is mixed with 10% hydrochloric acid solution, soaked overnight (such as 8 - 16 hours, preferably 10 - 12 hours), then filtered, washed, and dried. Among them, the particle size distribution of the substrate is 30 - 150 μm, preferably 60 - 120 μm, more preferably 25 - 60 μm.
[0015] In step (2), the pretreated synthetic mica is mixed with an organic solvent to form a suspension. The stirring rate is controlled at 100 - 500 rpm, preferably 200 - 300 rpm, and the temperature is controlled at -20°C - 60°C, preferably 0°C - 40°C. The pH value is adjusted to the hydrolysis pH of the organometallic salt, and then the organometallic salt solution is added for hydrolysis coating, so that the thickness of the metal oxide film layer reaches 100 - 250 nm, preferably 120 - 220 nm, more preferably 150 - 200 nm.
[0016] The organic solvents include methanol, ethanol, isopropanol, ethyl acetate, dichloromethane, toluene, xylene, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, etc.
[0017] The organometallic salt solution is one or more of tetraethyl titanate, tetraisopropyl titanate, tetrabutyl titanate, tetraoctyl titanate, iron(III) acetylacetonate, iron(III) oxalate, iron(III) citrate, tetraethoxysilane, tetraethoxy zirconium, tetra-n-propoxy zirconium, tetramethyltin, cobalt(II) acetylacetonate, cobalt(II) oxalate, hexamethyldicobalt(III) oxide, trimethylaluminum, aluminum isopropoxide or chromium acetate.
[0018] The method for isolating air is vacuum pumping or introducing a protective gas, and the protective gas can be selected from N2, He, Ne or Ar.
[0019] From the above technical solutions, it can be seen that compared with the existing technologies, the beneficial effects of the present invention are as follows: The present invention uses an organometallic salt as the precursor of the metal oxide layer for coating, so that there are residues of organic components in the metal oxide layer. Then, it is calcined under air isolation conditions to carbonize the organic components and dope them in the metal oxide layer, and a pearlescent pigment with high saturation can be obtained. This method has the characteristics of safe and easily available raw materials, simple and safe operation, environmental friendliness, low equipment cost and energy consumption, strong scintillation and high color saturation. This method can be used for seed coating, paints, printing inks, plastics, ceramic materials, leather coloring, wallpapers, powder coatings, cosmetics, automotive coatings or outdoor coatings. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope of the present invention. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.
[0021] Figure 1 It is a super-depth-of-field microscope image of the pearlescent pigment before (left) and after (right) calcination obtained in Example 1.
[0022] Figure 2 SEM images of the pearlescent pigments before (left) and after (right) calcination obtained in Example 2.
[0023] Figure 3 SEM images of the pearlescent pigments before (left) and after (right) calcination obtained in Example 3.
[0024] Figure 4 SEM image of the high-saturation pearlescent pigment obtained in Example 1.
[0025] Figure 5 SEM image of the high-saturation pearlescent pigment obtained in Example 2.
[0026] Figure 6 SEM image of the high-saturation pearlescent pigment obtained in Example 3.
[0027] Figure 7 Reflection spectrum of the high-saturation pearlescent pigment obtained in Example 1.
[0028] Figure 8 Reflection spectrum of the high-saturation pearlescent pigment obtained in Example 2.
[0029] Figure 9 Reflection spectrum of the high-saturation pearlescent pigment obtained in Example 3.
[0030] Figure 10 Cross-sectional SEM image of the high-saturation pearlescent pigment obtained in Example 1.
[0031] Figure 11 Cross-sectional SEM image of the high-saturation pearlescent pigment obtained in Example 2.
[0032] Figure 12 Cross-sectional SEM image of the high-saturation pearlescent pigment obtained in Example 3.
[0033] Figure 13 Element mapping of the high-saturation pearlescent pigment obtained in Example 1.
[0034] Figure 14 Cross-sectional SEM image of fluorophlogopite powder.
[0035] Table 1 is the element distribution table of the high-saturation pearlescent pigment obtained in Example 1. Detailed implementation mode
[0036] To deepen the understanding of the present invention, the present invention will be further described in detail below in combination with embodiments. The following embodiments are only used to explain the present invention and do not constitute a limitation to the protection scope of the present invention.
[0037] Example 1
[0038] (1) Weigh 105 g of synthetic mica with a particle size of 30 - 150 μm and put it into 500 mL of 10% hydrochloric acid. Mix evenly to form a slurry. After soaking for 8 h, filter by suction, wash, and dry for later use; (2) Weigh 100 g of the synthetic mica dried in the above step (1) and put it into a 3000 mL three-necked flask. Add 1000 mL of absolute ethanol, start stirring, and the rotation speed is 300 rpm; (3) Adjust the temperature to 10 °C, adjust the pH to 8.0 with ammonia water, add 500 mL of an ethanol solution of tetrabutyl titanate with a concentration of 0.2 mol / L. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate. A purplish-red color appears, and a purplish-red pearlescent pigment is obtained. Stop the reaction, filter by suction, wash, and dry; (4) Put the pearlescent pigment obtained in the above step (3) into a tube furnace and calcine it under a N₂ atmosphere. First, heat it up to 500 °C and keep it for 3 h, then heat it up to 1000 °C, keep it for 2 h, and then cool it naturally to obtain a high-saturation purplish-red pearlescent pigment.
[0039] Figure 1 Figure of the ultra-depth-of-field microscope of the pearlescent pigment before (left) and after (right) calcination obtained in Example 1. Figure 7 Reflection spectrum diagram of the high-saturation pearlescent pigment obtained in Example 1, and the maximum reflection wavelength is 398 nm. Figure 10 Cross-sectional scanning electron microscope diagram of the high-saturation pearlescent pigment obtained in Example 1, and the thickness of the metal oxide film is 146 nm. Table 1 is the element distribution table of the high-saturation pearlescent pigment obtained in Example 1, and the content of carbon doping is 15.57 wt%.
[0040] Table 1
[0041] Example 2
[0042] (1) Weigh 155 g of synthetic mica with a particle size of 60 - 120 μm and put it into 750 mL of 10% hydrochloric acid solution. Mix evenly to form a slurry. After soaking for 8 h, filter by suction, wash, and dry for later use; (2) Weigh 150 g of the synthetic mica dried in the above step (1) and put it into a 3000 mL three-necked flask. Add 1000 mL of absolute methanol, start stirring, and the rotation speed is 250 rpm; (3) Adjust the temperature to -10°C, adjust the pH to 9.0 with ammonia water, add 750 mL of a methanol solution of titanium tetraisopropoxide at 0.25 mol / L. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate, which shows purple, obtaining purple pearlescent pigment. Stop the reaction, perform suction filtration, washing, and drying; (4) Put the pearlescent pigment obtained in the above step (3) into a tube furnace and calcine it under an Ar atmosphere. First, heat it up to 400°C and hold for 2 h, then heat it up to 900°C and hold for 3 h, and then let it cool naturally to obtain a high-saturation purple pearlescent pigment.
[0043] Figure 2 It is the ultra-depth-of-field microscope images of the pearlescent pigment before (left) and after (right) calcination obtained in Example 2. Figure 8 It is the reflection spectrum diagram of the high-saturation pearlescent pigment obtained in Example 2, and the maximum reflection wavelength is 402 nm. Figure 11 It is the cross-sectional scanning electron microscope image of the high-saturation pearlescent pigment obtained in Example 2, and the thickness of the metal oxide film is 195 nm.
[0044] Example 3
[0045] (1) Weigh 105 g of synthetic mica with a particle size of 25 - 60 μm and put it into 500 mL of 10% hydrochloric acid solution, mix evenly to form a slurry. After soaking for 8 h, perform suction filtration, washing, and drying for later use; (2) Weigh 100 g of the dried synthetic mica obtained in the above step (1) and put it into a 3000 mL three-necked flask, add 1000 mL of isopropanol, and start stirring at a speed of 200 rpm; (3) Adjust the temperature to 40°C, adjust the pH to 5.0 with acetic acid, add 500 mL of an isopropanol solution of tetraethoxy zirconium at 0.3 mol / L. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate, which shows blue, obtaining blue pearlescent pigment. Stop the reaction, perform suction filtration, washing, and drying; (4) Put the pearlescent pigment obtained in the above step (3) into a tube furnace and calcine it under a He atmosphere. First, heat it up to 400°C and hold for 2 h, then heat it up to 1000°C and hold for 3 h, and then let it cool naturally to obtain a high-saturation blue pearlescent pigment.
[0046] Figure 3 It is the ultra-depth-of-field microscope images of the pearlescent pigment before (left) and after (right) calcination obtained in Example 3. Figure 9 It is the reflection spectrum diagram of the high-saturation pearlescent pigment obtained in Example 3, and the maximum reflection wavelength is 443 nm. Figure 12 It is the cross-sectional scanning electron microscope image of the high-saturation pearlescent pigment obtained in Example 3, and the thickness of the metal oxide film is 146 nm.
[0047] Example 4
[0048] (1)Weigh 205 g of glass flakes with a particle size of 30 - 150 μm and put them into 1000 mL of 10% sodium carbonate solution. Mix them evenly to form a slurry. After soaking for 8 h, filter by suction, wash, and dry for later use; (2)Weigh 200 g of the dried glass flakes from the above step (1) and put them into a 5000 - mL three - necked flask. Add 2000 mL of ethyl acetate and start stirring at a speed of 400 rpm; (3)Adjust the temperature to - 20 °C, adjust the pH to 9.0 with ammonia water, add 800 mL of an ethyl acetate solution of tetraethyl orthotitanate with a concentration of 0.2 mol / L. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate, showing a golden color, and a golden pearlescent pigment is obtained; (4)Adjust the temperature to 40 °C, adjust the pH to 8.0 with acetic acid, add 400 mL of an ethyl acetate solution of tetraethoxysilane with a concentration of 0.1 mol / L. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate, showing a golden color and its color does not change. Stop the reaction, filter by suction, wash, and dry; (5)Put the pearlescent pigment obtained in the above step (4) into a vacuum tube furnace and calcine it in a vacuum environment. First, heat it to 400 °C and keep it for 2 h, then heat it to 1000 °C and keep it for 3 h, and then cool it naturally to obtain a high - saturation golden pearlescent pigment.
[0049] Example 5
[0050] (1)Weigh 105 g of glass flakes with a particle size of 60 - 120 μm and put them into 500 mL of 10% sodium carbonate solution. Mix them evenly to form a slurry. After soaking for 8 h, filter by suction, wash, and dry for later use; (2)Weigh 100 g of the dried glass flakes from the above step (1) and put them into a 3000 - mL three - necked flask. Add 1000 mL of dichloromethane and start stirring at a speed of 200 rpm; (3)Adjust the temperature to 60 °C, adjust the pH to 10.0 with ammonia water, add 50 mL of a dichloromethane solution of tetramethyltin with a concentration of 0.1 mol / L, and react for a period of time; (4)Adjust the temperature to 10 °C, adjust the pH to 9.0 with acetic acid, add 600 mL of a dichloromethane solution of tetraoctyl orthotitanate with a concentration of 0.2 mol / L. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate, showing a cyan color, and a cyan pearlescent pigment is obtained; (5) Adjust the temperature to 30 °C, adjust the pH to 8.0 with acetic acid, add 200 mL of an ethyl acetate solution of 0.15 mol / L tetraethoxysilane. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing a cyan color, and its color does not change. Stop the reaction, filter, wash, and dry; (6) Put the pearlescent pigment obtained in the above step (5) into a tube furnace and calcine it under a Ne atmosphere. First, heat it to 400 °C and keep it for 2 h, then heat it to 900 °C and keep it for 3 h, and then cool it naturally to obtain a high-saturation cyan pearlescent pigment.
[0051] Example 6
[0052] (1) Weigh 105 g of glass flakes with a particle size of 25 - 60 μm and put them into 500 mL of 10% sodium carbonate solution, mix evenly to form a slurry. After soaking for 8 h, filter, wash, and dry for later use; (2) Weigh 100 g of the dried glass flakes obtained in the above step (1) and put them into a 3000 mL three-necked flask, add 1000 mL of absolute ethanol, and start stirring at a speed of 200 rpm; (3) Adjust the temperature to -20 °C, adjust the pH to 9.0 with ammonia water, add 200 mL of an ethanol solution of 0.2 mol / L trimethylaluminum, and react for a period of time; (4) Adjust the temperature to 0 °C, adjust the pH to 8.0 with acetic acid, add 600 mL of an ethanol solution of 0.25 mol / L iron acetylacetonate, and react for a period of time. Then, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing a red color, and obtain a red pearlescent pigment; (5) Adjust the temperature to 30 °C, add 200 mL of an ethanol solution of 0.2 mol / L tetraethoxysilane, and react for a period of time. Then, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing a red color, and its color does not change. Stop the reaction, filter, wash, and dry; (6) Put the pearlescent pigment obtained in the above step (5) into a tube furnace and calcine it under a N2 atmosphere. First, heat it to 400 °C and keep it for 2 h, then heat it to 600 °C and keep it for 3 h, and then cool it naturally to obtain a high-saturation red pearlescent pigment.
[0053] Example 7
[0054] (1) Weigh 105 g of alumina flakes with a particle size of 30 - 150 μm and put them into 500 mL of deionized water, mix evenly to form a slurry, and ultrasonically clean it with an ultrasonic cleaner for 30 min. Then filter, wash, and dry for later use; (2) Weigh 100 g of the dried alumina flakes in the above step (1), put them into a 3000 mL three-necked flask, add 1000 mL of isopropanol, start stirring, and the rotation speed is 200 rpm; (3) Adjust the temperature to -20 °C, adjust the pH to 5.0 with acetic acid, add 700 mL of an isopropanol solution of 0.2 mol / L tetra-n-propoxyzirconium. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing purple, and obtain purple pearlescent pigment; (4) Adjust the temperature to 30 °C, adjust the pH to 8.0 with ammonia water, add 200 mL of an isopropanol solution of 0.2 mol / L tetraethoxysilane. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing purple, and its color does not change; (5) Adjust the temperature to -20 °C, adjust the pH to 5.0 with acetic acid, add 700 mL of an isopropanol solution of 0.2 mol / L tetra-n-propoxyzirconium. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing green, and obtain green pearlescent pigment; (6) Adjust the temperature to 30 °C, adjust the pH to 8.0 with ammonia water, add 200 mL of an isopropanol solution of 0.2 mol / L tetraethoxysilane. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing green, and its color does not change. Then carry out suction filtration, washing, and drying; (7) Put the pearlescent pigment obtained in the above step (6) into a tubular furnace and calcine it under an Ar atmosphere. First, heat it up to 400 °C and keep it for 2 h, then heat it up to 1000 °C and keep it for 3 h, and then cool it naturally to obtain a high-saturation green pearlescent pigment.
[0055] Example 8
[0056] (1) Weigh 105 g of alumina flakes with a particle size of 60 - 120 μm, put them into 500 mL of deionized water solution, mix evenly to form a slurry, ultrasonicate it with an ultrasonic cleaner for 30 min, then carry out suction filtration, washing, and drying for later use; (2) Weigh 100 g of the dried alumina flakes in the above step (1), put them into a 3000 mL three-necked flask, add 1000 mL of anhydrous methanol, start stirring, and the rotation speed is 300 rpm; (3) Adjust the temperature to -10 °C, adjust the pH to 9.0 with ammonia water, add 750 mL of a methanol solution of 0.25 mol / L tetra-isopropyl titanate. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing purple, and obtain purple pearlescent pigment; (4) Adjust the temperature to 10°C, adjust the pH to 8.0 with acetic acid, add 600 mL of a methanol solution of 0.25 mol / L ferric citrate. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate, showing red, and a red pearlescent pigment is obtained; (5) Adjust the temperature to 30°C, add 200 mL of an ethanol solution of 0.2 mol / L tetraethoxysilane. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate, showing red, and its color does not change. Stop the reaction, filter by suction, wash, and dry; (6) Put the pearlescent pigment obtained in the above step (5) into a tubular furnace and calcine it under a N2 atmosphere. First, heat it to 400°C and keep it for 2 h, then heat it to 800°C and keep it for 3 h, and then cool it naturally to obtain a high-saturation red pearlescent pigment.
[0057] Example 9
[0058] (1) Weigh 105 g of alumina flakes with a particle size of 25 - 60 μm, put them into 500 mL of deionized water, mix evenly to form a slurry, ultrasonicate it with an ultrasonic cleaner for 30 min, then filter by suction, wash, and dry for later use; (2) Weigh 100 g of the dried alumina flakes obtained in the above step (1), put them into a 3000 mL three-necked flask, add 1000 mL of ethyl acetate, and start stirring at a speed of 300 rpm; (3) Adjust the temperature to 0°C, adjust the pH to 9.0 with ammonia water, add 750 mL of an ethyl acetate solution of 0.2 mol / L tetrabutyl titanate. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate, showing gold, and a golden pearlescent pigment is obtained; (4) Adjust the temperature to 10°C, adjust the pH to 8.0 with acetic acid, add 600 mL of an ethyl acetate solution of 0.25 mol / L cobalt acetylacetonate. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate, showing blue, and a blue pearlescent pigment is obtained; (5) Adjust the temperature to 30°C, add 200 mL of an ethanol solution of 0.2 mol / L tetraethoxysilane. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate, showing blue, and its color does not change. Stop the reaction, filter by suction, wash, and dry; (6) Put the pearlescent pigment obtained in the above step (5) into a tubular furnace and calcine it under a He atmosphere. First, heat it to 400°C and keep it for 2 h, then heat it to 900°C and keep it for 3 h, and then cool it naturally to obtain a high-saturation blue pearlescent pigment.
[0059] Example 10
[0060] (1) Weigh 105 g of natural mica with a particle size of 30 - 150 μm, put it into 500 mL of 10% hydrochloric acid solution, mix evenly to form a slurry, filter by suction, wash, and dry after soaking for 8 h for later use; (2) Weigh 100 g of the dried synthetic mica from the above step (1), put it into a 3000 mL three-necked flask, add 1000 mL of dimethyl sulfoxide, start stirring, and the rotation speed is 250 rpm; (3) Adjust the temperature to -20 °C, adjust the pH to 9.0 with ammonia water, add 200 mL of a dimethyl sulfoxide solution of trimethylaluminum with a concentration of 0.2 mol / L, and react for a period of time; (4) Adjust the temperature to 0 °C, adjust the pH to 8.0 with acetic acid, add 600 mL of a dimethyl sulfoxide solution of chromium acetate with a concentration of 0.25 mol / L, after reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing green, and a green pearlescent pigment is obtained; (5) Adjust the temperature to 30 °C, add 200 mL of a dimethyl sulfoxide solution of tetraethoxysilane with a concentration of 0.2 mol / L, after reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing green, and its color does not change, stop the reaction, filter by suction, wash, and dry; (6) Put the pearlescent pigment obtained in the above step (5) into a vacuum tube furnace, calcine it under a vacuum environment, first heat up to 400 °C and keep it for 2 h, then heat up to 800 °C and keep it for 3 h, and then cool down naturally to obtain a high-saturation green pearlescent pigment.
[0061] Example 11
[0062] (1) Weigh 105 g of natural mica with a particle size of 60 - 120 μm, put it into 500 mL of 10% hydrochloric acid solution, mix evenly to form a slurry, filter by suction, wash, and dry after soaking for 8 h for later use.
[0063] (2) Weigh 100 g of the dried synthetic mica from the above step (1), put it into a 3000 mL three-necked flask, add 1000 mL of xylene, start stirring, and the rotation speed is 250 rpm; (3) Adjust the temperature to 0 °C, adjust the pH to 9.0 with ammonia water, add 500 mL of a xylene solution of tetrabutyl titanate with a concentration of 0.2 mol / L, after reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing cyan, and a cyan pearlescent pigment is obtained; (4) Adjust the temperature to 30°C, adjust the pH to 8.0 with acetic acid, add 200 mL of a xylene solution of 0.2 mol / L tetraethoxysilane. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing a cyan color, and its color does not change; (5) Adjust the temperature to 0°C, adjust the pH to 9.0 with ammonia water, add 500 mL of a xylene solution of 0.2 mol / L tetrabutyl titanate. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing a purple color, and obtain a purple pearlescent pigment; (6) Adjust the temperature to 30°C, adjust the pH to 8.0 with acetic acid, add 200 mL of a xylene solution of 0.2 mol / L tetraethoxysilane. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing a purple color, and its color does not change. Then perform suction filtration, washing, and drying; (7) Put the pearlescent pigment obtained in the above step (6) into a tubular furnace and calcine it under a He atmosphere. First, heat it up to 400°C and keep it for 2 h, then heat it up to 1000°C and keep it for 3 h, and then cool it naturally to obtain a high-saturation purple pearlescent pigment.
[0064] Example 12
[0065] (1) Weigh 105 g of natural mica with a particle size of 25 - 60 μm, put it into 500 mL of 10% hydrochloric acid solution, mix evenly to form a slurry, soak it for 8 h, then perform suction filtration, washing, and drying for later use.
[0066] (2) Weigh 100 g of the dried synthetic mica obtained in the above step (1), put it into a 3000 mL three-necked flask, add 1000 mL of isopropanol, start stirring, and the rotation speed is 250 rpm; (3) Adjust the temperature to 0°C, adjust the pH to 8.0 with ammonia water, add 600 mL of an isopropanol solution of 0.25 mol / L iron acetylacetonate. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing a golden color, and obtain a golden pearlescent pigment; (4) Adjust the temperature to 30°C, add 200 mL of an isopropanol solution of 0.2 mol / L tetraethoxysilane. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing a golden color, and its color does not change; (5) Adjust the temperature to 0°C, adjust the pH to 8.0 with ammonia water, add 600 mL of an isopropanol solution of 0.25 mol / L iron acetylacetonate. After reacting for a period of time, suck a small amount of the reaction solution with a dropper and drop it on a black acrylic plate, showing a red color, and obtain a red pearlescent pigment; (6) Adjust the temperature to 30 °C, add 200 mL of an isopropanol solution of tetraethoxysilane with a concentration of 0.2 mol / L. After reacting for a period of time, use a dropper to suck a small amount of the reaction solution and drop it on a black acrylic plate. It shows red and its color does not change. Stop the reaction, carry out suction filtration, washing, and drying; (7) Put the pearlescent pigment obtained in the above step (6) into a tube furnace and calcine it under a Ne atmosphere. First, heat it up to 400 °C and keep it for 2 h, then heat it up to 600 °C and keep it for 3 h, and then let it cool naturally to obtain a high-saturation red pearlescent pigment.
[0067] The above content is only an example and explanation of the specific implementation manners of the present invention. It should be pointed out that when modifications, supplements, or similar replacements are made to the above implementation manners according to the concept of the present invention, and the functions and effects generated still do not exceed the spirit covered by the specification, they should all be within the protection scope of the present invention.
Claims
1. A carbon-doped pearlescent pigment, characterized in that, It includes a pearlescent pigment base layer, and a metal oxide layer is coated on the outer side of the pearlescent pigment base layer, and carbon element is doped in the metal oxide layer; The thickness of the pearlescent pigment base layer is 0.1 - 2 μm, and the thickness of the metal oxide layer is 100 - 500 nm; The doping amount of the carbon element accounts for 10 - 30 wt% of the amount of the pearlescent pigment.
2. The pearlescent pigment according to claim 1, characterized in that, The pearlescent pigment base layer is one or more of natural mica, synthetic mica, glass flakes, and alumina flakes.
3. The pearlescent pigment according to claim 2, wherein, The pearlescent pigment base layer is synthetic mica.
4. The pearlescent pigment according to claim 1, characterized in that, The metal oxide layer of the pearlescent pigment is one or more of titanium dioxide, iron(III) oxide, zirconium dioxide, tin dioxide, iron titanate, silicon dioxide, chromium(III) oxide, cobalt oxide, zirconium silicate, zirconium hydroxide, and aluminum oxide.
5. The method for preparing the pearlescent pigment according to any one of claims 1-4, characterized in that, It includes the following steps: (A)Stir the substrate evenly in hydrochloric acid solution, soak it, then wash, filter, and dry it for later use; (B)Make the pretreated synthetic mica after drying into a slurry with an organic solvent, and carry out hydrolysis coating by adding an organometallic salt solution until the metal oxide coating reaches an iridescent hue; (C)Finally, calcine it in an airtight manner to obtain the carbon-doped pearlescent pigment.
6. The preparation method of the pearlescent pigment according to claim 5, characterized in that, In the step (A), the substrate is mixed with hydrochloric acid solution, soaked for 8 - 16 hours, then filtered, washed, and dried; the particle size distribution of the substrate is 30 - 150 μm.
7. The method for preparing the pearlescent pigment according to claim 5, characterized in that, In the step (B), the organic solvent is one or more of methanol, ethanol, isopropanol, ethyl acetate, dichloromethane, toluene, xylene, tetrahydrofuran, N,N-dimethylformamide, and dimethyl sulfoxide.
8. The preparation method of the pearlescent pigment according to claim 5, characterized in that, In the step (B), the pretreated synthetic mica is mixed with the organic solvent to form a suspension, the stirring rate is controlled at 100 - 500 rpm, the temperature is controlled at -20℃ - 60℃, the pH value is adjusted to the hydrolysis pH of the organometallic salt, and the organometallic salt solution is added for hydrolysis coating so that the thickness of the metal oxide film layer reaches 100 - 250 nm.
9. The method for preparing the pearlescent pigment according to claim 8, wherein, The organometallic salt solution is one or more of tetraethyl titanate, tetraisopropyl titanate, tetrabutyl titanate, tetraoctyl titanate, iron(III) acetylacetonate, iron(III) oxalate, iron(III) citrate, tetraethoxysilane, tetraethoxyzirconium, tetra-n-propoxyzirconium, tetramethyltin, cobalt(III) acetylacetonate, cobalt(III) oxalate, hexamethyldicobalt(III) oxide, trimethylaluminum, aluminum isopropoxide, or chromium(III) acetate.
10. The method for preparing the pearlescent pigment according to claim 5, wherein, In the step (C), the method of isolating air is to evacuate or introduce a protective gas, and the protective gas is N2, He, Ne, or Ar.