A kind of imitated green vegetation nanometer composite pigment and its preparation method

Abstract

The application discloses an imitated green vegetation nanometer composite pigment and a preparation method thereof, and belongs to the field of visible light-near infrared camouflage materials. First, water-soluble magnesium salt and aluminum salt are co-precipitated with compound active dyes in alkaline condition, and the obtained solid compound graphene is centrifuged together with sodium polyacrylate, and then the nanometer composite pigment is prepared through spray drying; then, the pigment is compounded with a binder, a thickening agent and water to form a color paste, and the color paste is printed on a fabric to obtain a camouflage fabric. The Mg-Al layered hydroxide is used to simulate the near infrared water peak of vegetation, the dye is compounded to restore the green appearance of vegetation, and the graphene and the sodium polyacrylate are used to synergistically control the spectrum and the moisture absorption performance. The product can reproduce the vegetation green peak, the red edge, the near infrared plateau and the characteristic water peak in the 400-2500 nm wave band, the spectral correlation coefficient is up to 98.2%, the color difference DE is less than 3, and the product meets the military camouflage standard; the material is heat-resistant, weather-resistant, and has strong environmental adaptability, and the preparation process is simple and easy to scale production.

Description

Technical Field

[0001] This invention belongs to the field of visible-near-infrared camouflage materials, specifically relating to a green vegetation-inspired nanocomposite pigment and its preparation method. Background Technology

[0002] In modern informationized battlefields, detection equipment such as hyperspectral remote sensing, infrared imaging, and UAV multi-band reconnaissance have achieved wide-range, high-precision, and all-weather target identification. Visible-near-infrared integrated camouflage has become a core technology for concealing combat personnel, military tents, and weapons, and evading enemy spectral reconnaissance, directly impacting the concealment and survivability of national defense operations. Existing camouflage materials must simultaneously match the green vegetation characteristics in the 400-780 nm visible light band and the 780-2500 nm near-infrared band to meet military camouflage standards.

[0003] Natural green vegetation possesses four key spectral characteristics: a green peak formed by chlorophyll near 545 nm, a red edge effect at 680 nm, a high-reflectance near-infrared plateau at 780–1300 nm, and characteristic water absorption valleys at 1450 nm, 1900 nm, and 2500 nm generated by the vibration of OH bonds in leaf water. While the visible light and near-infrared plateau regions can be largely simulated using conventional organic dyes and inorganic green pigments, replicating the 1200–2500 nm near-infrared water peak remains a common technical challenge in the industry.

[0004] Current mainstream camouflage coloring materials have significant shortcomings: Single reactive dye systems: Reactive yellow, blue, and green compound dyes can match the visible light color of vegetation and the near-infrared plateau reflectance curve, but their molecular structure does not contain groups that can stably adsorb water, and they cannot generate near-infrared characteristic water peaks, making them easily exposed under hyperspectral detection; moreover, the dyes have poor heat resistance and weather resistance, and are prone to fading and spectral curve shift after long-term outdoor use; Traditional inorganic green pigments (cobalt green, chrome green, pigment green 36 / 7, etc.): can only achieve a basic green appearance, and their near-infrared reflectance curves differ greatly from those of vegetation, with no obvious water absorption valley, low spectral similarity, and color difference that is difficult to meet the requirements of military camouflage color standards DG0850 and MG1151. Some heavy metal pigments also have defects in environmental protection and textile processing fastness.

[0005] Furthermore, the existing patent CN104194406A discloses a method for preparing nano-oxide composite pigments. This patent uses silicon dioxide and titanium dioxide silicon-based nano-oxides as carriers and relies on the sol-gel method to prepare composite pigments. Although it can improve the lightfastness of pigments, this patent is fundamentally different from the technical principle of this invention: CN104194406A only relies on the nano-oxide carrier to perform simple physical adsorption and binding of reactive dyes. There is no stable interlayer composite structure between the dye and the inorganic carrier, and the binding force between the two is weak, so it cannot achieve spectral control. Moreover, silicon-based oxides do not have interlayer hydroxyl groups and adsorbed water that can be stably retained. They do not have the ability to replicate the near-infrared characteristic water peaks of vegetation. They can only improve the lightfastness of pigments and do not have the function of camouflaging vegetation spectrum in the visible-near-infrared full-band.

[0006] In summary, existing camouflage materials struggle to simultaneously replicate the four major spectral characteristics of vegetation—green peak, red edge, near-infrared plateau, and water peak—across the entire 400–2500 nm wavelength range. Their color matching accuracy, spectral stability, environmental adaptability, and textile processing performance all fall short of the GJB 1411-2015 Level 1 spectral camouflage standard and the GBJ 1082A-2021 camouflage net color standard. Developing a green vegetation-inspired nanocomposite pigment that can accurately simulate the full-spectrum of vegetation, meets color standards, exhibits excellent thermal stability and weather resistance, and is suitable for mass production in textile printing is a pressing technical need in the field of military camouflage materials. Summary of the Invention

[0007] Technical issues Existing conventional camouflage materials cannot accurately replicate the green peak, red edge, near-infrared plateau and water peak spectral characteristics of green vegetation in the entire 400~2500 nm wavelength range at the same time. They also have problems such as poor color matching, insufficient thermal stability and weather resistance, and difficulty in adapting to various battlefield environments.

[0008] Technical content To address the aforementioned technical issues, this invention employs Mg-Al layered hydroxide as a matrix. The hydroxyl groups within the layers and the adsorbed water between the layers generate near-infrared absorption peaks similar to those of plant leaves. Furthermore, the water content within the layers can be controlled through synthesis conditions, thereby adjusting the intensity and position of the water peak. A co-precipitation process is used to embed a compounded reactive dye into the interlayer of the Mg-Al layered hydroxide, relying on the dye to recreate the green appearance of vegetation. Graphene is then added to regulate near-infrared reflectivity, and highly hygroscopic sodium polyacrylate is used to further optimize the water peak simulation effect, resulting in a nanocomposite pigment mimicking green vegetation. This pigment can precisely match the spectrum and color of vegetation in the 400~2500nm range, meeting the requirements of GJB 1411-2015 Level 1 optical and spectral camouflage. The color can match national standard camouflage nets DG0850 and MG1151. The product exhibits excellent heat resistance, weather resistance, and stability. The preparation process is simple and highly efficient, supporting continuous mass production. It can be applied to textile camouflage equipment such as military camouflage clothing and camouflage nets, providing a reliable and convenient technical solution for visible-near-infrared camouflage processing.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing a nanocomposite pigment that mimics green vegetation, the method comprising the following steps: Magnesium salts, aluminum salts, and reactive dyes were mixed in water, the pH was adjusted to alkaline, and then the mixture was heated and stirred. The solid was then collected by centrifugation and mixed with graphene solution and sodium polyacrylate. Finally, the mixture was spray-dried to obtain nanocomposite pigments.

[0010] Furthermore, the magnesium salt is a water-soluble magnesium salt, including magnesium chloride, magnesium nitrate, magnesium sulfate, magnesium acetate, and magnesium citrate.

[0011] Furthermore, the aluminum salt is a water-soluble aluminum salt, including aluminum chloride, aluminum nitrate, and aluminum sulfate.

[0012] Furthermore, the molar ratio of magnesium salt to aluminum salt is 1 to 5:1.

[0013] Furthermore, the molar ratio of magnesium salt to aluminum salt is 3~4:1.

[0014] Furthermore, reactive dyes include any two or more of reactive yellow, reactive blue, or reactive green.

[0015] Furthermore, the reactive yellow dyes include CI Reactive 145, CI Reactive Yellow 160, CI Reactive Yellow 3, CI Reactive Yellow 84, and CI Reactive Yellow 205.

[0016] Furthermore, the reactive blue dyes include CI Reactive Blue 19, CI Reactive Blue 194, CI Reactive Blue 221, and CI Reactive Blue 21.

[0017] Furthermore, the reactive green dyes include CI Reactive Green 12 and CI Reactive Green 19.

[0018] Furthermore, the reactive yellow dye is one or more of CI Reactive 145, CI Reactive Yellow 160, CI Reactive Yellow 3, CI Reactive Yellow 84, and CI Reactive Yellow 205.

[0019] Furthermore, the reactive blue dye is one or more of CI Reactive Blue 19, CI Reactive Blue 194, CI Reactive Blue 221, and CI Reactive Blue 21.

[0020] Furthermore, the reactive green dye is one or more of CI Reactive Green 12 and CI Reactive Green 19.

[0021] Specifically, the reactive dye is a combination of reactive yellow and reactive blue; or a combination of reactive yellow, reactive blue and reactive green.

[0022] Furthermore, the reactive dye is a combination of reactive yellow and reactive blue in a mass ratio of 1 to 5:1.

[0023] Furthermore, the reactive dye is a combination of reactive yellow and reactive blue in a mass ratio of 2 to 3:1.

[0024] Furthermore, the reactive dye is a combination of reactive yellow, reactive blue, and reactive green in a mass ratio of 1 to 5:1:0.05.

[0025] Furthermore, the total molar amount of magnesium salt and aluminum salt and the molar ratio of reactive dye are 10~30:1.

[0026] Furthermore, the total molar ratio of magnesium salt and aluminum salt to reactive dye is 15~25:1.

[0027] Furthermore, the molar concentration of magnesium salts in the mixed water is 50–150 mmol / L.

[0028] Furthermore, adjust the pH to 8-11.

[0029] Furthermore, the heating and stirring temperature is 40~70 ℃, and the time is 1~10 hours.

[0030] Furthermore, the concentration of graphene in the graphene solution is 1~50 mg / mL.

[0031] Furthermore, the concentration of graphene in the graphene solution is 1~10 mg / mL.

[0032] Furthermore, the graphene in the graphene solution has a thickness of 0.5–3.0 nm, a sheet diameter of 0.5–5 μm, a number of layers of 1–2, a monolayer efficiency of >98%, and a specific surface area of ​​1000–1217 m². 2 / g.

[0033] Furthermore, the amount of graphene solution added is 0.1~1 wt% of the solid mass.

[0034] Furthermore, the amount of graphene solution added is 0.1~0.5 wt% of the solid mass.

[0035] Furthermore, the process of adding graphene solution can be equivalently replaced by adding dry graphene solid and water.

[0036] Furthermore, the amount of sodium polyacrylate added is 5 to 30 wt% of the solid mass.

[0037] Furthermore, the amount of sodium polyacrylate added is 5 to 20 wt% of the solid mass.

[0038] Furthermore, the spray drying inlet air temperature is 110~150℃, and the outlet air temperature is 50~80℃.

[0039] This invention provides a nanocomposite pigment for mimicking green vegetation, prepared according to the above method.

[0040] The nanocomposite pigment for imitating green vegetation provided by this invention can be used in the field of camouflage, including formulating the nanocomposite pigment as a dye to print and dye fabrics to obtain camouflage fabrics with an imitation green vegetation spectrum.

[0041] The present invention also provides a printing paste for imitating green vegetation, the printing paste comprising: 3-10 wt% of the nano-composite pigment obtained above, 3-10 wt% of binder, 5-10 wt% of thickener, and the balance being water.

[0042] The present invention also provides a printed fabric that mimics green vegetation, which is obtained by printing the above-mentioned printing paste onto the surface of the fabric and then drying it.

[0043] Furthermore, the fabric includes cotton fabric, nylon fabric, and non-woven fabric.

[0044] Beneficial effects (1) Compared with existing physical adsorption systems, this invention uses Mg-Al layered hydroxide as an inorganic matrix and uses an alkaline co-precipitation process to embed reactive dyes into the interlayer of layered hydroxides. It forms a stable organic-inorganic complex by relying on interlayer forces, rather than simple physical adsorption. On the one hand, it inherits the excellent light fastness of reactive dye coloring systems. On the other hand, it relies on the interlayer hydroxyl groups and adsorbed water of layered hydroxides, and is synergistically regulated by graphene and sodium polyacrylate to completely replicate the full-band spectral characteristics of green vegetation. At the same time, it accurately matches the standard colors of military camouflage, which can improve light fastness and achieve spectral camouflage.

[0045] (2) This invention can completely replicate the four major spectral characteristics of vegetation in the visible-near infrared range of 400~2500 nm: green peak, red edge, near-infrared plateau, and water peak. The spectral similarity can reach up to 98.2%, which meets the first-level optical and spectral camouflage requirements of GJB 1411-2015. By accurately adjusting the color with compound reactive dyes, the color difference of the finished product is ΔE<3, which meets the color standard of camouflage net DG0850 and MG1151 of GBJ 1082A-2021 "camouflage coating film color camouflage net color". The spectral and color simulation effect is far superior to traditional inorganic green pigments, single dyes, pure magnesium aluminum layered hydroxides and other comparative materials.

[0046] (3) This invention relies on the interlayer hydroxyl groups of Mg-Al LDH and adsorbed water, combined with highly hygroscopic sodium polyacrylate. With a moisture absorption rate of ≥10%, it can stably display the characteristic water peaks of vegetation, making it suitable for the high-humidity outdoor environment of jungles. The layered carrier is coated with reactive dyes and modified with graphene, which greatly improves the heat resistance and weather resistance of the material. It is not easy to fade, the spectral curve is not easy to shift, and the camouflage effect is long-lasting. At the same time, the reflectivity and water peak intensity can be flexibly controlled by adjusting the ratio of each raw material to meet different vegetation simulation needs. Attached Figure Description

[0047] Figure 1 This is a schematic diagram illustrating the preparation process and application of nanocomposite pigments.

[0048] Figure 2 The microstructure of nanocomposite pigments.

[0049] Figure 3 This is a physical image of a nanocomposite pigment.

[0050] Figure 4 This is a comparison image of Example 1 in a green vegetation corridor.

[0051] Figure 5 This is a comparison image of Example 2 in a green vegetation corridor.

[0052] Figure 6 This is a comparison image of Example 3 in a green vegetation corridor.

[0053] Figure 7 Comparison images of Examples 1, 2, 3, 4, and 5 in the green vegetation corridor.

[0054] Figure 8 Comparative figures for Examples 6 and 7 and Examples 1, 2 and 3 in green vegetation corridors. Detailed Implementation

[0055] Source of raw materials Nylon, cotton, and nonwoven fabrics were purchased from Huafang Co., Ltd.; magnesium chloride hexahydrate and anhydrous aluminum chloride were purchased from Sinopharm Chemical Reagent Co., Ltd.; reactive dyes were purchased from Taixing Jinyun Dye Co., Ltd.; and aqueous graphene dispersion (GNS) was purchased from Suzhou Carbon-Feng Technology Co., Ltd., with a concentration of 1-5 mg / mL, a graphene purity of 99 wt%, a thickness of 0.5-3.0 nm, a sheet diameter of 0.5-5 μm, approximately 1-2 graphene layers in the aqueous dispersion, a monolayer rate >98%, and a specific surface area of ​​1000-1217 m². 2 / g, the solution is black; sodium polyacrylate (PAAS) was purchased from Shanghai Mairui Biochemical Technology Co., Ltd.; thickener DM-5221G and adhesive DM-5218 were purchased from Wuxi Huishan Demei Chemical Co., Ltd.

[0056] Testing process Fabric moisture absorption rate test: After the fabric is humidified to a certain extent, it is placed in a constant temperature and humidity chamber with a humidity of 95%~100% and a temperature of 25℃. After 24 hours of equilibrium, its weight is weighed. The weight after moisture absorption minus the weight before moisture absorption, divided by the weight after moisture absorption, multiplied by 100, equals the moisture absorption rate.

[0057] The spectral simulation method is as follows: Spectral simulation calculations were performed and the spectral simulation degree was evaluated in accordance with standard GJB 1411A-2015. The spectral distance d with the leaves of the Japanese maple, the spectral P correlation coefficient, and the spectral angle θ (rad) were calculated. The visible-near-infrared reflectance spectral curve of the fabric was tested using a Lambda 950 UV-Vis-NIR spectrophotometer under the following test conditions: 400-2500nm, 5nm, R.

[0058] The color simulation method is as follows: Using a DC850 computer colorimeter, the L*, a*, b* values ​​and color difference ΔE of the sample are tested according to standard GJB 798-2020, and the color similarity is evaluated.

[0059] Example 1 Preparation of composite pigments: Prepare solutions of 100 mmol / L MgCl2, 100 mmol / L AlCl3, and 10 mmol / L reactive dye (CI Reactive Yellow 145:CI Reactive Blue 21 at a mass ratio of 2:1), then add MgCl2 by molar ratio.2+ :Al 3+ A mixed salt solution was prepared by ratio 3:1, and then an active dye solution was added at a volume ratio of 2:1. The pH was then adjusted to 8.5, and the mixture was shaken at 50 °C for 2 h. After standing for 12 h, the solid was collected by centrifugation and washing. 0.15 wt% GNS and 5 wt% PAAS were added relative to the solid mass, and the mixture was ultrasonically dispersed. Finally, it was spray-dried (air inlet at 130 °C, air outlet at 70 °C) to obtain the nanocomposite pigment.

[0060] Nylon woven fabric printing: The printing paste is prepared for printing on nylon fabric. The paste formula is: 5wt% nano-composite pigment, 5wt% binder, 8wt% thickener, and the remainder is water. The printing process is to print the printing paste on the surface of the nylon fabric, and then bake the fabric at 150 ℃ for 3 minutes to obtain the imitation green leaf printed fabric.

[0061] Example 2 Preparation of composite pigments: Prepare solutions of 100 mmol / L MgCl2, 100 mmol / L AlCl3, and 10 mmol / L reactive dye (CI Reactive Yellow 145:CI Reactive Blue 21 at a mass ratio of 3:1), then add MgCl2 by molar ratio. 2+ :Al 3+ A 3:1 mixed salt solution was prepared, and then a dye solution was added at a volume ratio of 2:1. The pH was adjusted to 9, and the mixture was shaken at 40°C for 4 hours. After standing for 16 hours, the solid was collected by centrifugation and washing. 0.15wt% GNS and 10wt% PAAS were added relative to the solid mass, and the mixture was ultrasonically dispersed. Finally, it was spray-dried (air inlet at 130°C, air outlet at 70°C) to obtain the nanocomposite pigment.

[0062] Non-woven fabric printing: The printing paste is used for non-woven fabric printing. The paste formula is: 5wt% nano-composite pigment, 5wt% binder, and 6wt% thickener. Printing process: The printing paste is printed on the surface of the non-woven fabric, and then the fabric is baked in a baking machine at 130℃ for 3 minutes to obtain the imitation green leaf non-woven fabric printed fabric.

[0063] Example 3 Preparation of composite pigments: Prepare a solution of 100 mmol / L MgCl2, 100 mmol / L AlCl3, and 10 mmol / L reactive dye (the mass ratio of CI Reactive Yellow 84: CI Reactive Blue 21: CI Reactive Green 21 is 2:1:0.05), then add MgCl2 by molar ratio. 2+ :Al 3+A 4:1 mixed salt solution was added, followed by a dye solution at a volume ratio of 2:1. The pH was then adjusted to 10, and the mixture was shaken at 60°C for 2 hours. After standing for 12 hours, the solid was collected by centrifugation and washing. 0.15 wt% GNS and 20 wt% PAAS were added relative to the solid mass, and the mixture was ultrasonically dispersed. Finally, it was spray-dried (150°C inlet air, 70°C outlet air) to obtain the nanocomposite pigment.

[0064] Cotton fabric printing: The printing paste is used for cotton fabric printing. The paste formula is: 5wt% nano-composite pigment, 5wt% binder, and 5wt% thickener. Printing process: The printing paste is printed on the surface of the cotton fabric, and then the fabric is baked in a baking machine at 180 ℃ for 3 minutes to obtain imitation green leaf printed fabric.

[0065] Comparative Example 1 Preparation of composite pigments: Prepare solutions of 100 mmol / L MgCl2 and 100 mmol / L AlCl3, then add MgCl2 at a molar ratio of 100 mmol / L MgCl2 and 100 mmol / L AlCl3. 2+ :Al 3+ A mixed salt solution was prepared at a ratio of 3:1, and the pH was adjusted to 8.5. The solution was shaken at 50 °C for 2 h, allowed to stand for 12 h, and then centrifuged and washed to collect the solid. 0.15 wt% GNS and 5 wt% PAAS were added relative to the solid mass, and the mixture was ultrasonically dispersed. Finally, it was spray-dried (air inlet at 130 °C and air outlet at 70 °C) to obtain the nanocomposite pigment.

[0066] Nylon woven fabric printing: The printing paste is prepared for printing on nylon fabric. The paste formula is: 5wt% nano-composite pigment, 5wt% binder, 8wt% thickener, and the remainder is water. The printing process is to print the printing paste on the surface of the nylon fabric, and then bake the fabric at 150 ℃ for 3 minutes to obtain the imitation green leaf printed fabric.

[0067] Comparative Example 2 Cobalt green G-6410 was used for printing on nylon fabric. The color paste formula was: 5 wt% pigment, 5 wt% binder, 8 wt% thickener, and the remainder was water. The printing process involved printing the color paste onto the surface of the nylon fabric, and then baking the fabric at 150 ℃ for 3 minutes to obtain the imitation green leaf printed fabric.

[0068] Comparative Example 3 Chrome Green G-6181 was used for printing on nylon fabric. The color paste formula was: 5 wt% pigment, 5 wt% binder, 8 wt% thickener, and the remainder was water. The printing process involved printing the color paste onto the surface of the nylon fabric, and then baking the fabric at 150 ℃ for 3 minutes to obtain the imitation green leaf printed fabric.

[0069] Comparative Example 4 Pigment Green 36 was used for printing on nylon fabric. The pigment paste formula was: 5wt% pigment, 5wt% binder, 8wt% thickener, and the remainder was water. The printing process involved printing the pigment paste onto the surface of the nylon fabric, and then baking the fabric at 150 ℃ for 3 minutes to obtain the imitation green leaf printed fabric.

[0070] Comparative Example 5 Pigment Green 7 was used for printing on nylon fabric. The pigment paste formula was: 5wt% pigment, 5wt% binder, 8wt% thickener, and the remainder was water. The printing process was to print the printing paste on the surface of the nylon fabric, and then bake the fabric at 150 ℃ for 3 min in a baking machine to obtain the imitation green leaf printed fabric.

[0071] Comparative Example 6 Dye Green 12 was used for printing on nylon fabric. The pigment paste formula was: 5wt% pigment, 5wt% binder, 8wt% thickener, and the remainder was water. The printing process involved printing the pigment paste onto the surface of the nylon fabric, and then baking the fabric at 150 ℃ for 3 minutes to obtain the imitation green leaf printed fabric.

[0072] Comparative Example 7 Dyes Blue 21 and Yellow 145 were mixed at a mass ratio of 3:1 and used for printing on nylon fabric. The color paste formula was: 5 wt% pigment, 5 wt% binder, 8 wt% thickener, and the remainder was water. The printing process involved printing the color paste onto the surface of the nylon fabric, and then baking the fabric at 150 ℃ for 3 min in a baking machine to obtain the imitation green leaf printed fabric.

[0073] Table 1 Spectral simulation results

[0074] Table 2 Color Simulation Results

[0075] Comparing the comparative examples and the embodiments, as shown in Table 1, embodiments 1, 2, and 3 all meet the requirements of spectral distance less than 5, spectral angle less than 0.2 rad, and spectral P-correlation coefficient greater than 90%, satisfying the requirements of Level 1 optical camouflage and Level 1 spectral camouflage in the visible-near-infrared spectral range of GJB 1411-2015 "Camouflage of Surface-to-Surface Missile Weapon Equipment Systems". As shown in Table 2, embodiments 1, 2, and 3 can simulate the camouflage net colors DG0850 and MG1151 of GBJ 1082A-2021 "Camouflage Coating Film Color and Camouflage Net Color", achieving a color difference ΔE of less than 3. The spectral simulation effect of comparative examples 1, 2, 3, 4, 5, 6, and 7 is not as good as that of the embodiments, and the colors also differ significantly from the camouflage net colors. In summary, embodiments 1, 2, and 3 can meet the requirements of the camouflage standards.

[0076] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for preparing a nanocomposite pigment that mimics green vegetation, characterized in that, The preparation method includes the following steps: Water-soluble magnesium salt, water-soluble aluminum salt and reactive dye are mixed in water, the pH is adjusted to alkaline and then heated and stirred. After centrifugation, the solid is collected and mixed with graphene solution and sodium polyacrylate. Finally, it is spray-dried to obtain nanocomposite pigment. The molar ratio of water-soluble magnesium salt to water-soluble aluminum salt is 1~5:1; The reactive dye is a combination of reactive yellow and reactive blue, or a combination of reactive yellow, reactive blue and reactive green; The total molar ratio of water-soluble magnesium salt and water-soluble aluminum salt to reactive dye is 10~30:1; The concentration of the graphene solution was 1–50 mg / mL; the amount of graphene solution added was 0.1–1 wt% of the solid mass. The amount of sodium polyacrylate added is 5-30 wt% of the solid mass.

2. The preparation method according to claim 1, characterized in that, The water-soluble magnesium salts include magnesium chloride, magnesium nitrate, magnesium sulfate, magnesium acetate, and magnesium citrate; the water-soluble aluminum salts include aluminum chloride, aluminum nitrate, and aluminum sulfate.

3. The preparation method according to claim 1, characterized in that, The reactive yellow dyes include CI Reactive 145, CI Reactive Yellow 160, CI Reactive Yellow 3, CI Reactive Yellow 84, and CI Reactive Yellow 205; the reactive blue dyes include CI Reactive Blue 19, CI Reactive Blue 194, CI Reactive Blue 221, and CI Reactive Blue 21; and the reactive green dyes include CI Reactive Green 12 and CI Reactive Green 19.

4. The preparation method according to claim 1, characterized in that, The reactive dyes are either a combination of reactive yellow and reactive blue in a mass ratio of 1 to 5:1, or a combination of reactive yellow, reactive blue, and reactive green in a mass ratio of 1 to 5:1:0.

05.

5. The preparation method according to claim 1, characterized in that, The concentration of the graphene solution is 1~10 mg / mL; the amount of graphene solution added is 0.1~0.5 wt% of the solid mass.

6. The preparation method according to claim 1, characterized in that, The amount of sodium polyacrylate added is 5-20 wt% of the solid mass.

7. The preparation method according to claim 1, characterized in that, The heating and stirring temperature is 40~70 ℃, and the time is 1~10 hours; the spray drying inlet air temperature is 110~150 ℃, and the outlet air temperature is 50~80 ℃.

8. A nanocomposite pigment that mimics green vegetation, characterized in that, The nanocomposite pigment is prepared by the preparation method according to any one of claims 1 to 7.

9. A printing paste that mimics green vegetation, characterized in that, The composition of the printing paste includes: 3-10 wt% of the nano-composite pigment as described in claim 8, 3-10 wt% of the binder, 5-10 wt% of the thickener, and the balance being water.

10. A printed fabric imitating green vegetation, characterized in that, The printed fabric is obtained by printing the printing paste described in claim 9 onto the surface of a fabric and then drying it; the fabric includes cotton fabric, nylon fabric, and non-woven fabric.

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