Magnesium-chromium hydrotalcite-like compound-based jungle camouflage coating and preparation method thereof

Abstract

The invention relates to a magnesium-chromium hydrotalcite-like compound-based jungle camouflage coating and a preparation method thereof. The visible-near infrared spectrum of the prepared magnesium-chromium hydrotalcite-like material has a blue-green characteristic, and the near-infrared water absorption peak of the magnesium-chromium hydrotalcite-like material can be increased by intercalating sulfate radicals between magnesium-chromium hydrotalcite-like layers. Besides, due to the fact that the chrome green pigment is small in particle and can cover the near-infrared water absorption peak of the hydrotalcite-like compound, sulfate radical intercalation magnesium-chromium hydrotalcite-like compound is selected to be coated on the basis of Cr2O3, then the coated chrome green pigment and the magnesium-chromium hydrotalcite-like compound are compounded to prepare the jungle camouflage coating, the plant spectrum similarity exceeds 95%, and the jungle camouflage coating has the advantages of being high in spectrum similarity, good in weather resistance, good in corrosion resistance and the like. The synthetic method has the advantages of simplicity, low cost and the like, and has higher military jungle camouflage application value.

Description

Technical Field

[0001] This invention relates to a magnesium-chromium hydrotalcite-based jungle camouflage coating and its preparation method. Background Technology

[0002] Jungle camouflage aims to conceal military targets by mimicking natural environmental features, making them difficult to detect and identify. Hyperspectral remote sensing can capture the spectral characteristics of vegetation in the visible, near-infrared, and short-wave infrared bands, identifying spectral differences between camouflaged targets and the natural background, demonstrating strong application potential in jungle camouflage detection and identification. Green vegetation exhibits four characteristics in the visible-near-infrared spectral region: green peak, red edge, plateau, and water absorption peak. By developing functional coating technology, designs can be created that are "colorless" and "spectrally identical" to green vegetation, achieving camouflage and concealment of targets.

[0003] Layered double hydroxides (LDHs), also known as double hydroxides, are anionic layered materials. By modulating the metal ions in the layers and the anions in the interlayers, LDH-like materials can be formed, finding wide applications in coatings, plastics, and drug delivery systems. LDH-like materials exhibit good thermal stability and are environmentally friendly and non-toxic, making them suitable for safe use as additives in coating materials. The abundant water molecules in the interlayers of LDH-like materials can simulate near-infrared water peaks in vegetation spectra, making them a high-performance material for simulating the visible-near-infrared spectrum of vegetation.

[0004] This invention prepares a magnesium-chromium-based hydrotalcite. This hydrotalcite material exhibits both blue-green characteristics and a near-infrared water absorption peak in its visible-near-infrared spectrum. Therefore, by modifying the interlayer anion of this hydrotalcite-like material and then combining it with chromium green pigment, a jungle camouflage functional coating with high spectral similarity can be prepared to simulate the spectrum of green plants. To match the green peak characteristics around 550 nm of green vegetation, a sulfate-intercalated magnesium-chromium-based hydrotalcite (MgCr-SO4) was selected as the substrate of Cr2O3. 2- -LDHs@Cr2O3). The addition of chrome green pigment effectively improved the green peak characteristics of hydrotalcite-like materials; however, due to the small particle size of chrome green, it masked the near-infrared water absorption peak characteristics of hydrotalcite-like materials. Therefore, this invention uses MgCr-SO4... 2- -LDHs coated with Cr2O3 react with MgCr-SO4 2- -LDHs were blended to prepare a jungle camouflage coating, which significantly improved the near-infrared water absorption peak effect while maintaining the green peak characteristics. Summary of the Invention

[0005] Existing jungle camouflage coatings on the market mainly consider spectral simulation in the 400-1100nm band, while research on simulation materials for bands above 1100nm is still not very complete. To overcome the problems of small near-infrared water absorption peaks, poor water peak retention, and the tendency of chrome green pigment to easily obscure the near-infrared water absorption peaks of hydrotalcite minerals due to its small particle size, this invention prepares a novel functional jungle camouflage coating by composite material composed of sulfate-intercalated magnesium chromium hydrotalcite and its coated chrome green pigment.

[0006] A magnesium-chromium hydrotalcite-based jungle camouflage coating is characterized as follows: it is a coating formed on spandex fabric, and the coating uses MgCr-SO4 in a mass ratio of 3:7:20. 2- -LDHs@Cr2O3、MgCr-SO4 2- The coating is made of LDHs and PVA adhesive, with a thickness of 30~50μm.

[0007] The specific preparation method is as follows: First, MgCr-SO4 2- -LDHs@Cr2O3 and MgCr-SO4 2- -LDHs were ground and mixed at a mass ratio of 3:7, and then the powder and PVA adhesive were mixed at a mass ratio of 1:2 and stirred until there were no obvious particles in the mixed solution. The prepared adhesive was then evenly coated onto the spandex fabric and dried in an oven at 160 ℃ for 10 min to obtain the jungle camouflage coating.

[0008] The MgCr-SO4 2- -LDHs were synthesized via coprecipitation: according to Mg 2+ / Cr 3+ MgSO4 and CrCl3·6H2O were dissolved in deionized water at a molar ratio of 3:1 to prepare solutions A and B. NaOH was then dissolved in deionized water and labeled as solution C. Solutions A, B, and C were added simultaneously with stirring at 80 °C, maintaining the pH between 9 and 10, with a dropwise addition time of 30 min. After the addition was complete, stirring was continued for another 30 min. The mixture was then crystallized in an oven at 65 °C for 8 h. After filtration and washing, the sample was dried at 65 °C for 12 h, pulverized, and labeled as MgCr-SO4. 2- -LDHs.

[0009] The MgCr-SO4 2- -LDHs@Cr2O3 was synthesized by a coprecipitation method. A certain mass of Cr2O3 was weighed and dispersed in deionized water, and then MgCr-SO4 was coated on the surface of Cr2O3. 2--LDHs (according to Cr2O3:MgCr-SO4) 2- -LDHs mass ratio 3:7); Cr2O3 surface MgCr-SO4 2- -LDHs coating synthesis according to Mg 2+ / Cr 3+ In a molar ratio of 3:1, the required amounts of MgSO4 and CrCl3·6H2O were dissolved in deionized water to prepare solutions A and B, respectively. Then, NaOH was dissolved in deionized water and labeled as solution C. Solutions A, B, and C were simultaneously added to the Cr2O3 solution while stirring at 80 °C, maintaining the pH between 9 and 10. The addition time was maintained at 30 min, followed by stirring for another 30 min after the addition was complete. The solution was then crystallized in an oven at 65 °C for 8 h. After filtration and washing, the solution was dried at 65 °C for 12 h and pulverized to obtain the sample, labeled as MgCr-SO4. 2- -LDHs@Cr2O3.

[0010] The magnesium-chromium hydrotalcite-based jungle camouflage functional coating synthesized in this invention has the advantages of high spectral similarity, good weather resistance, simple synthesis method, and low cost, and has high application value in military jungle camouflage applications. Attached Figure Description

[0011] Figure 1 MgCr-SO4 2- -LDHs, MgCr-SO4 2- -LDHs@Cr2O3, Cr2O3:MgCr-SO4 2- -LDHs=3:7, MgCr-SO4 2- -LDHs@Cr2O3:MgCr-SO4 2- -LDHs=3:7 preparation of visible-near infrared spectra of coatings and plant leaves.

[0012] Figure 2 MgCr-SO4 2- -LDHs, MgCr-SO4 2- -LDHs@Cr2O3, Cr2O3:MgCr-SO4 2- -LDHs=3:7, MgCr-SO4 2- -LDHs@Cr2O3:MgCr-SO4 2- -LDHs=3:7 and CIE chromaticity diagrams for Leaf; in the diagram, (a) MgCr-SO4 2- -LDHs, (b) MgCr-SO4 2- -LDHs@Cr2O3, (c) Cr2O3:MgCr-SO4 2--LDHs=3:7, (d)MgCr-SO4 2- -LDHs@Cr2O3:MgCr-SO4 2- -LDHs =3:7, (L) Leaf.

[0013] Figure 3 MgCr-SO4 2- -LDHs@Cr2O3:MgCr-SO4 2- Thermal imaging of the camouflage coating prepared by -LDHs = 3:7. Detailed Implementation

[0014] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention. Example

[0015] A magnesium-chromium hydrotalcite-based jungle camouflage coating, the preparation method of which involves: MgCr-SO4 2- -LDHs@Cr2O3 and MgCr-SO4 2- -LDHs were ground and mixed at a mass ratio of 3:7, and then the powder and PVA adhesive were mixed at a mass ratio of 1:2 and stirred until there were no obvious particles in the mixed solution. The prepared adhesive was then evenly coated on the spandex fabric and dried in an oven at 160 ℃ for 10 min to obtain a jungle camouflage coating with a thickness of about 30~50μm, which was recorded as sample 1.

[0016] The MgCr-SO4 2- -LDHs were synthesized via coprecipitation: according to Mg 2+ / Cr 3+ MgSO4 and CrCl3·6H2O were dissolved in deionized water at a molar ratio of 3:1 to prepare solutions A and B. NaOH was then dissolved in deionized water and labeled as solution C. Solutions A, B, and C were added simultaneously with stirring at 80 °C, maintaining the pH between 9 and 10, with a dropwise addition time of 30 min. After the addition was complete, stirring was continued for another 30 min. The mixture was then crystallized in an oven at 65 °C for 8 h. After filtration and washing, the sample was dried at 65 °C for 12 h, pulverized, and labeled as MgCr-SO4. 2- -LDHs.

[0017] The MgCr-SO4 2--LDHs@Cr2O3 was synthesized by a coprecipitation method. A certain mass of Cr2O3 was weighed and dispersed in deionized water, and then MgCr-SO4 was coated on the surface of Cr2O3. 2- -LDHs (according to Cr2O3:MgCr-SO4) 2- -LDHs mass ratio 3:7); Cr2O3 surface MgCr-SO4 2- -LDHs coating synthesis according to Mg 2+ / Cr 3+ In a molar ratio of 3:1, the required amounts of MgSO4 and CrCl3·6H2O were dissolved in deionized water to prepare solutions A and B, respectively. Then, NaOH was dissolved in deionized water and labeled as solution C. Solutions A, B, and C were simultaneously added to the Cr2O3 solution while stirring at 80 °C, maintaining the pH between 9 and 10. The addition time was maintained at 30 min, followed by stirring for another 30 min after the addition was complete. The solution was then crystallized in an oven at 65 °C for 8 h. After filtration and washing, the solution was dried at 65 °C for 12 h and pulverized to obtain the sample, labeled as MgCr-SO4. 2- -LDHs@Cr2O3. Example

[0018] As a comparative experiment, MgCr-SO4 2- -LDHs are used to make jungle camouflage coatings, and the preparation method is as follows: MgCr-SO4 2- -LDHs and PVA adhesive are mixed in a 1:2 mass ratio and stirred until there are no obvious particles in the mixed solution; then the above-prepared adhesive is evenly coated on the spandex fabric and dried in an oven at 160 ℃ for 10 min to obtain a camouflage coating with a thickness of about 30~50μm, which is recorded as sample 2. Example

[0019] As a comparative experiment, MgCr-SO4 2- -LDHs@Cr2O3 was used to create a jungle camouflage coating, the preparation method of which involves: using MgCr-SO4 2- -LDHs@Cr2O3 and PVA adhesive are mixed in a mass ratio of 1:2 and stirred until there are no obvious particles in the mixed solution; then the above-prepared adhesive is evenly coated on spandex fabric and dried in an oven at 160 ℃ for 10 min to obtain a camouflage coating with a thickness of about 30~50μm, which is recorded as sample 3. Example

[0020] As a comparative experiment, Cr2O3 and MgCr-SO4 were used. 2--LDHs were ground and mixed at a mass ratio of 3:7, and then the powder and PVA adhesive were mixed at a mass ratio of 1:2 and stirred until there were no obvious particles in the mixed solution. The prepared adhesive was then evenly coated on the spandex fabric and dried in an oven at 160 ℃ for 10 min to obtain a camouflage coating with a thickness of about 30~50μm, which was designated as sample 4.

[0021] This invention is made from MgCr-SO4 2- -LDHs, MgCr-SO4 2- -LDHs@Cr2O3, Cr2O3:MgCr-SO4 2- -LDHs=3:7, MgCr-SO4 2- -LDHs@Cr2O3:MgCr-SO4 2- The camouflage coating prepared with -LDHs=3:7 and the visible-near infrared spectra of plant leaves, such as Figure 1 As shown.

[0022] To compare the spectral similarity between camouflage coatings and green vegetation, a spectral similarity (SCC) calculation method was introduced to compare the spectra of each coating with those of the plants. The calculation results are listed in Table 1.

[0023] Table 1. Spectral similarity of various camouflage coatings Types of camouflage coatings Spectral similarity <![CDATA[MgCr-SO4 2- -LDHs@Cr2O3]]> 86.69% <![CDATA[Cr2O3:MgCr-SO4 2- -LDHs=3:7]]> 90.91% <![CDATA[MgCr-SO4 2- -LDHs@Cr2O3:MgCr-SO4 2- -LDHs=3:7]]> 95.80% The camouflage coating was compared with the near-infrared spectral similarity of common vegetation in the 400–2500 nm range. MgCr-SO4 2- The spectral similarity of -LDHs@Cr2O3 was 86.69%, Cr2O3: MgCr-SO4 2- The spectral similarity of -LDHs=3:7 was 90.91%. The highest similarity, reaching 95.80%, was obtained when chromium green was coated with magnesium chromium-based hydrotalcite and then mixed with hydrotalcite. The results indicate that MgCr-SO4... 2- -LDHs@Cr2O3 and MgCr-SO4 2- The camouflage coating prepared by blending -LDHs has excellent jungle camouflage performance.

[0024] Figure 2 The color of each coating is blue-green, with significant differences. The Lab color test values ​​for the coatings are listed in Table 2. (MgCr-SO4) 2- -LDHs has the highest L* value of 57.3, making it the brightest, while the other three coatings are darker than the color of leaves; Table 2 Lab color values ​​of camouflage coatings Sample types L* a* b* <![CDATA[MgCr-SO4 2- -LDHs]]> 57.3 -4.76 -5.14 <![CDATA[MgCr-SO4 2- -LDHs@Cr2O3]]> 46.22 -4.08 -0.75 <![CDATA[Cr2O3:MgCr-SO4 2- -LDHs=3:7]]> 41.85 -1.34 -0.04 <![CDATA[MgCr-SO4 2- -LDHs@Cr2O3:MgCr-SO4 2- -LDHs=3:7]]> 42.81 -1.84 -2.52 Leaf 52.02 -0.05 -3.15 The a* values ​​of all four coatings were lower than the plant a* value (-0.05), indicating that the prepared coatings were all greenish. Among them, MgCr-SO4... 2- -LDHs@Cr2O3:MgCr-SO4 2- The b* value of -LDHs=3:7 is -2.52, which is closest to the b* value of plants (-3.15). The overall color difference of this coating is closest to that of plants.

[0025] Using thermal imaging to examine MgCr-SO4 2- -LDHs@Cr2O3:MgCr-SO4 2- The jungle camouflage coating prepared with -LDHs=3:7 was compared with the thermal imaging images of plant tests, such as... Figure 3 As shown. Figure 3 In (a) and (b), the camouflage coating was made into the shape of a leaf and placed in bushes and various leaves. The thermal images of the coating did not show significant differences from the plant leaves. Figure 3 In (c), the camouflage coating is compared with a similarly shaped plant placed on the arm. The camouflage coating shows a clear thermal image, demonstrating its excellent thermal concealing ability.

Claims

1. A magnesium-chromium hydrotalcite-based jungle camouflage coating, characterized in that: For coatings formed on spandex fabrics, the coating uses MgCr-SO4 in a mass ratio of 3:7:

20. 2- -LDHs@Cr2O3、MgCr-SO4 2- The coating is made of LDHs and PVA adhesive, with a thickness of 30~50μm.

2. A method for preparing a magnesium-chromium hydrotalcite-based jungle camouflage coating, characterized in that: First, MgCr-SO4 2- -LDHs@Cr2O3 and MgCr-SO4 2- -LDHs were ground and mixed at a mass ratio of 3:7, and then the powder and PVA adhesive were mixed at a mass ratio of 1:2 and stirred until there were no obvious particles in the mixed solution. The prepared adhesive was then evenly coated onto the spandex fabric and dried in an oven at 160 ℃ for 10 min to obtain the jungle camouflage coating.

3. The method for preparing a magnesium-chromium hydrotalcite-based jungle camouflage coating as described in claim 2, characterized in that: The MgCr-SO4 2- The preparation method of -LDHs is as follows: according to Mg 2+ / Cr 3+ MgSO4 and CrCl3·6H2O were dissolved in deionized water at a molar ratio of 3:1 to prepare solutions A and B, respectively. NaOH was then dissolved in deionized water and labeled as solution C. Solutions A, B, and C were added simultaneously with stirring at 80 °C, maintaining the pH between 9 and 10, with a dropping time of 30 min. After the addition was complete, stirring was continued for another 30 min. The mixture was then crystallized in an oven at 65 °C for 8 h. After filtration and washing, the sample was dried at 65 °C for 12 h, pulverized, and labeled as MgCr-SO4. 2- -LDHs.

4. The method for preparing a magnesium-chromium hydrotalcite-based jungle camouflage coating as described in claim 2, characterized in that: The MgCr-SO4 2- The preparation method of -LDHs@Cr2O3 is as follows: a certain mass of Cr2O3 is weighed and dispersed in deionized water, and then MgCr-SO4 is coated on the surface of Cr2O3. 2- -LDHs (according to Cr2O3:MgCr-SO4) 2- -LDHs mass ratio 3:7); Cr2O3 surface MgCr-SO4 2- -LDHs coating synthesis according to Mg 2+ / Cr 3+ In a molar ratio of 3:1, the required amounts of MgSO4 and CrCl3·6H2O were dissolved in deionized water to prepare solutions A and B, respectively. Then, NaOH was dissolved in deionized water and labeled as solution C. Solutions A, B, and C were simultaneously added to the Cr2O3 solution while stirring at 80°C. The pH of the solution was maintained between 9 and 10, and the addition time was maintained at 30 min. After the addition was complete, stirring was continued for another 30 min. The solution was then crystallized in an oven at 65°C for 8 h. After filtration and washing, the solution was dried at 65°C for 12 h and pulverized to obtain the sample, which was labeled as MgCr-SO4. 2- -LDHs@Cr2O 3。

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