Bionic camouflage paint for military industry and preparation method thereof

Abstract

The application discloses a kind of bionic camouflage paint for military industry and a preparation method thereof.The camouflage paint comprises acrylic resin, hydroxy acrylic resin, environment-friendly solvent, defoaming agent, leveling agent, catalyst, ultraviolet light absorber, ultraviolet light hindered stabilizer, filler, pigment and bionic filler. Visible light and near-infrared camouflage performance, natural vegetation texture and high bionic stereoscopic visual effect are considered.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a biomimetic camouflage coating for military use and its preparation method. Background Technology

[0002] Camouflage coatings are commonly used to conceal military installations, defense fortifications, military equipment, and to prevent enemy reconnaissance of targets. More important camouflage coatings include camouflage paint and radar-resistant paint.

[0003] 1) Camouflage paint: (1) Protective camouflage paint. The characteristics of this paint should be adapted to the background color. For example, when the background is grassland, the paint is green; when the background is desert, the paint is sandy; when the background is snow, the paint is white, etc. At present, single-color camouflage paint is mainly green. Suitable for this kind of chlorophyll camouflage is generally anti-infrared camouflage paint. Green camouflage paint mostly uses chromium oxide green and carbon black as pigments, and the base material is alkyd resin and epoxy resin. In recent years, in order to improve the chemical resistance and mechanical properties of camouflage paint, the base material has been expanded to polyurethane resin, etc. (2) Deformation camouflage paint. The characteristic of this paint is that it can distort the shape of the target, making its image distorted. It is mainly used for the camouflage of moving targets such as tanks, cars, and cannons. This paint usually uses irregular spot patterns and multiple pigments to achieve camouflage. At present, foreign countries have developed single colors (such as military green) with different infrared reflectances to form patterns.

[0004] 2) Radar-absorbing coatings: These coatings are used in radar countermeasures by the army, navy, and air force. They are unaffected by changes in light, humidity, and ambient temperature, and can be used on ships, aircraft, rockets, and various buildings. The base materials used in foreign radar-absorbing coatings mainly include chloroprene rubber, polyisobutylene, butyl rubber, polyurethane, polyvinyl chloride, epoxy resin, polyacrylate, and polyester; the pigments and fillers mainly include smoke black, graphite, flake aluminum powder, and ceramics.

[0005] Patent CN111978846A discloses a biomimetic camouflage coating composition that protects against visible light and near-infrared detection. By using a biomimetic camouflage coating composition with a specific composition, combined with dispersion and grinding processes, it solves the problem that existing infrared camouflage coatings cannot achieve visible light camouflage during the day. It achieves an effective camouflage effect in both visible light and infrared bands and simplifies the production process.

[0006] Patent CN119637951A discloses a camouflage material, a hyperspectral camouflage coating, its preparation method and application. By modifying cobalt / chromium system materials with lithium, a novel camouflage material of type Co2Cr3TiLiNiO10 is prepared, which solves the problem that existing hyperspectral camouflage materials cannot meet the requirements of spectral reflection channels, and realizes efficient simulation and camouflage effect of the spectral characteristics of yellow-green vegetation.

[0007] However, current camouflage coatings still have the problem of not being able to simultaneously achieve visible light and near-infrared camouflage performance, natural vegetation texture, and highly biomimetic stereoscopic visual effects. Summary of the Invention

[0008] The purpose of this invention is to overcome the problems existing in the prior art and provide a biomimetic camouflage coating for military use and its preparation method.

[0009] To achieve the above objectives, the present invention provides a biomimetic camouflage coating for military applications, comprising the following components in parts by weight: acrylic resin: 20-25 parts; hydroxyl acrylic resin: 10-15 parts; environmentally friendly solvent: 4-10 parts; defoamer: 0.3-0.5 parts; leveling agent: 0.4-0.7 parts; catalyst: 0.01-0.02 parts; ultraviolet light absorber: 0.5-1.0 parts; ultraviolet light blocking stabilizer: 0.5-1.0 parts; filler: 25-35 parts; pigment: 25-30 parts; biomimetic filler: appropriate amount.

[0010] Preferably, the acrylic resin is MACRYNAL SM516 / 70BAC, with a solid content of 70% and a hydroxyl value of 120 mg KOH / g; Preferably, the hydroxyl acrylic resin is CTR-6225, with a solid content of 60% and a hydroxyl value of 100 mg KOH / g; Preferably, the environmentally friendly solvent is propylene glycol methyl ether acetate and / or butyl alkyd; Preferably, the ultraviolet light absorber is Tinuvin 1130; Preferably, the UV-blocking stabilizer is Tinuvin 292; Preferably, the filler is talc powder with a particle size of 5-15 μm and a whiteness ≥90%; Preferably, the pigment is a color paste, including various color pastes used to simulate the colors of natural vegetation such as trees, woodlands, grasslands, and swamps.

[0011] Preferably, the biomimetic filler is wood chips and / or grass chips with a particle size of 0.1-2 mm and an irregular shape, used to imitate the texture and surface morphology of natural vegetation.

[0012] Preferably, the coating also includes a curing agent, which is a polyisocyanate curing agent, and the amount added is 5-10% of the weight of the coating.

[0013] Preferably, the weight ratio of each component is as follows: 22 parts acrylic resin, 12 parts hydroxy acrylic resin, 7 parts environmentally friendly solvent, 0.4 parts defoamer, 0.5 parts leveling agent, 0.015 parts catalyst, 0.8 parts ultraviolet light absorber, 0.8 parts ultraviolet light blocking stabilizer, 30 parts filler, 27 parts pigment, and 2 parts biomimetic filler.

[0014] This invention also provides a method for preparing a biomimetic camouflage coating for military use, comprising the following steps: (1) Add acrylic resin, hydroxy acrylic resin, environmentally friendly solvent, defoamer and leveling agent to a mixing container and stir at 400-500 rpm for 10-15 minutes to obtain mixture A; (2) Add pigment, catalyst, ultraviolet light absorber and ultraviolet light blocking stabilizer to mixture A, and stir at high speed to obtain mixture B; (3) Add filler to mixture B and stir at 800-1000 rpm for 15-20 minutes to obtain mixture C; (4) Add biomimetic filler to mixture C and stir at low speed for 10-15 minutes; (5) Filter the mixture D to remove impurities, and package it to obtain the military biomimetic camouflage coating.

[0015] Preferably, the high-speed stirring speed in step (2) is 1200-1500 rpm, and the stirring time is 20-30 minutes.

[0016] Preferably, the speed of the low-speed stirring in step (4) is 300-500 rpm.

[0017] Preferably, the process further includes a step of mixing the coating with a curing agent before application, wherein the curing agent is a polyisocyanate curing agent and is added at an amount of 5-10% of the weight of the coating.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) By selecting pigments (pastes) with specific spectral characteristics and combining them with acrylic resin and hydroxyl acrylic resin systems, visible light and near-infrared reflective camouflage characteristics can be achieved.

[0019] (2) By adding biomimetic fillers, mainly wood chips and grass chips, the texture and surface morphology of natural vegetation are imitated, giving the camouflage coating an appearance similar to natural vegetation and enhancing the camouflage effect. The irregular shape and size distribution of the biomimetic fillers give the coating surface an uneven natural texture with a three-dimensional visual effect, making it difficult to distinguish from natural vegetation when observed up close; it combines visible light and near-infrared camouflage performance, natural vegetation texture, and highly biomimetic three-dimensional visual effect.

[0020] (3) The synergistic effect of UV absorbers and UV-blocking stabilizers effectively improves the UV aging resistance of the coating and extends the service life of the coating.

[0021] (4) Using environmentally friendly solvents (propylene glycol methyl ether acetate, butyl alkyd), and with an optimized resin / solvent ratio, the VOC content was tested according to GB / T23986.2-2023 and was 372-398 g / L. Referring to the VOC limit requirements (≤780 g / L) of the solvent-based "Other Industrial Coatings" category in GB30981.2-2025 "Limits of Hazardous Substances in Coatings Part 2: Industrial Coatings", the VOC content of the coating of this invention is only about 50% of the standard, and its environmental performance is at the leading level among similar solvent-based camouflage coatings. Attached Figure Description

[0022] Figure 1 The curves show the spectral reflectance of the light green camouflage coating of this invention. Curve #1 is the measured curve of the coating of this invention, and curve #2 is the average reflectance curve of natural vegetation in the wild. The two curves have a high degree of overlap, which proves that the visible light and near-infrared spectra of the coating are highly matched with those of natural vegetation, thus achieving multi-band compatible camouflage. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0024] Example 1 A biomimetic camouflage coating for military use, comprising the following components in parts by weight: MACRYNAL SM516 / 70BAC acrylic resin (Zhanxin Resin (China) Co., Ltd., solid content 70%, hydroxyl value 120mgKOH / g): 22 parts; CTR-6225 hydroxyl acrylic resin (CNOOC Changzhou Environmental Protection Coatings Co., Ltd., solid content 60%, hydroxyl value 100mgKOH / g): 12 parts; Propylene glycol methyl ether acetate (Jiangsu Hualunxing Juhe Chemical Co., Ltd., environmentally friendly solvent): 4 parts; Butyl alkyd (Taixing Jinjiang Chemical Co., Ltd., environmentally friendly solvent): 3 parts; BYK-141 defoamer (BYK Additives (Shanghai) Co., Ltd.): 0.4 parts; Efka FL3777N leveling agent (BASF Chemical Co., Ltd., Shanghai): 0.3 parts; BYK-323 leveling agent (BYK Additives (Shanghai) Co., Ltd.): 0.2 parts; Dibutyltin dilaurate catalyst (Qingdao Shisi Chemical Co., Ltd.): 0.015 parts; Tinuvin 1130 UV absorber (BASF Chemical Co., Ltd., Shanghai): 0.8 parts; Tinuvin 292 UV-blocking stabilizer (BASF Chemical Co., Ltd., Shanghai): 0.8 parts; Domestic talc powder (Changzhou Yale Color Trading Co., Ltd., particle size 5-15μm, whiteness 92%): 30 parts; Green pigment paste (Titanium Yang Chemical Pigment (Shanghai) Co., Ltd.): 25 parts; Wood chips (particle size 0.5-1.5mm): 1.5 parts; Grass clippings (particle size 0.1-0.5mm): 0.5 parts; Preparation method: (1) Add MACRYNAL SM516 / 70BAC, CTR-6225, propylene glycol methyl ether acetate, butyl alkyd, BYK-141, and Efka FL3777N to a mixing container and stir at 450 rpm for 12 minutes to obtain mixture A; (2) Add green pigment, dibutyltin dilaurate, Tinuvin 1130 and Tinuvin 292 to mixture A, and stir at 1400 rpm for 25 minutes to obtain mixture B; (3) Add domestic talc powder to mixture B and stir at 900 rpm for 18 minutes to obtain mixture C; (4) Add sawdust and straw to mixture C and stir at a low speed of 400 rpm for 12 minutes to avoid breaking the biomimetic filler; (5) Filter the mixture through a 200-mesh filter to remove impurities, and package it to obtain the military biomimetic camouflage coating.

[0025] Application method: Before use, mix the coating with the polyisocyanate curing agent (such as Bayhydur N75) at a mass ratio of 10:1. Apply by spraying or brushing, and control the coating thickness to 30-50μm. Cur at room temperature for 24 hours or bake at 60℃ for 30 minutes.

[0026] Example 2 The difference from Example 1 is that the pigment used is a brown pigment paste (simulating the color of tree trunks or soil), and the biomimetic filler consists of 3 parts wood chips and 1 part grass chips. Other components and preparation methods are the same as in Example 1.

[0027] Example 3 The difference from Example 1 is that the pigment used is a gray-based color paste (simulating the color of rocks or deserts), and the biomimetic filler consists of 1 part wood chips and 2 parts grass chips. Other components and preparation methods are the same as in Example 1.

[0028] Example 4 The difference from Example 1 is that the pigment used is a black / dark gray pigment (simulating the color of a swamp or forest), and the biomimetic filler consists of 2 parts wood chips and 1 part grass chips. Other components and preparation methods are the same as in Example 1.

[0029] Example 5 The difference from Example 1 is that the amount of propylene glycol methyl ether acetate, butyl alkyd, talc, and biomimetic filler was adjusted to 5 parts, 5 parts, 25 parts, and 5 parts (3 parts wood chips and 2 parts straw chips). Other components and preparation methods are the same as in Example 1.

[0030] Example 6 The difference from Example 1 is that the amount of propylene glycol methyl ether acetate was adjusted to 3 parts, the amount of butyl alkyd was adjusted to 1 part, the amount of talc was adjusted to 35 parts, and the total amount of biomimetic filler was adjusted to 0.5 parts (0.3 parts of wood chips and 0.2 parts of straw chips). Other components and preparation methods are the same as in Example 1.

[0031] Comparative Example 1 The difference from Example 1 is that no biomimetic filler is added. Other components and preparation methods are the same as in Example 1.

[0032] Comparative Example 2 The difference from Example 1 is that hydroxyl acrylic resin (CTR-6225) is not added. Other components and preparation methods are the same as in Example 1.

[0033] Comparative Example 3 The difference from Example 1 is that no ultraviolet light absorber and ultraviolet light blocking stabilizer are added. Other components and preparation methods are the same as in Example 1.

[0034] Comparative Example 4 The difference from Example 1 is that the pigment used is a common organic pigment (such as phthalocyanine green). The other components and preparation methods are the same as in Example 1.

[0035] Performance testing The coatings prepared in Examples 1-6 and Comparative Examples 1-4 were subjected to performance tests, and the test methods are as follows: (1) Optical camouflage performance test: The test method refers to GJB1411A-2015 "General Specification for Military Optical Camouflage Materials". The spectral reflectance characteristics of the coating in the 400-2500nm band were tested using an ultraviolet-visible-near-infrared spectrophotometer (Shimadzu UV-3600), and the similarity coefficient with the spectrum of standard natural background (trees, woodland, grassland, swamp, etc.) was calculated.

[0036] (2) Visual stereoscopic effect: The surface morphology of the coating was observed using a 3D microscope (Keyence VHX-5000), and the surface roughness (Ra value) was measured. Five evaluators were invited to conduct a visual evaluation to assess the similarity between the coating and the natural vegetation (5-point scale: 5 points - very similar, 4 points - similar, 3 points - average, 2 points - poor, 1 point - poor).

[0037] (3) Adhesion performance test: The adhesion performance is tested in accordance with GB / T9286-1998 "Cross-cut test of paint and varnish film" and the adhesion grade is evaluated (0-5, with 0 being the best).

[0038] (4) Pencil hardness test: The test shall be conducted in accordance with GB / T6739-2006 "Determination of hardness of paint film by pencil method for paint and varnish" and the pencil hardness (H) shall be recorded.

[0039] (5) Water resistance test: The test shall be conducted in accordance with GB / T1733-1993 "Test Method for Water Resistance of Paint Film", and the blistering and peeling of the paint film shall be recorded.

[0040] (6) Weather resistance test: The test shall be conducted in accordance with GB / T1865-2009 "Artificial weathering and artificial radiation exposure of paints and varnishes and filtered xenon arc radiation", and the ΔE value of color change and gloss retention rate shall be recorded.

[0041] (7) Salt spray resistance test: The test shall be conducted in accordance with GB / T1771-2007 "Determination of resistance to neutral salt spray of paints and varnishes", and the blistering and corrosion of the paint film shall be recorded.

[0042] (8) VOC content test: The VOC content (g / L) shall be calculated in accordance with Clause 11.4 of GB / T23986.2-2023 "Determination of volatile organic compounds (VOC) and / or semi-volatile organic compounds (SVOC) content in paints and varnishes - Part 2: Determination of VOC content by difference method".

[0043] Table 1. Basic performance test results of Examples 1-6 and Comparative Examples 1-4

[0044] Table 2. Camouflage performance test results of Examples 1-6 and Comparative Examples 1-4

[0045] Table 3. VOC content and construction performance of Examples 1-6 and Comparative Examples 1-4

[0046] The test results in Tables 1-3 show that: (1) The military-grade biomimetic camouflage coating of the present invention has an adhesion grade of 0-1 and a pencil hardness of H-2H. It passes water resistance and salt spray resistance tests, and the paint film shows no bubbles or rust, demonstrating excellent weather resistance. The principle is as follows: The dual-resin system (acrylic resin MACRYNAL SM516 / 70BAC and hydroxyl acrylic resin CTR-6225) used in this invention reacts with a polyisocyanate curing agent to form an interpenetrating network structure. This structure increases the crosslinking density, effectively preventing the penetration of moisture and corrosive media, improving water resistance and salt spray resistance; it effectively disperses stress, improving the hardness and adhesion of the coating; and it also helps to fix pigments and fillers. The present invention uses the ultraviolet light absorber Tinuvin 1130 and the ultraviolet light hindered stabilizer Tinuvin 292. The ultraviolet light absorber can absorb ultraviolet rays of 290-400nm, and the ultraviolet light hindered stabilizer can capture free radicals and prevent chain degradation reaction. The synergistic effect of the two effectively inhibits the aging and discoloration of the coating under ultraviolet irradiation and extends the service life of the coating.

[0047] (2) The spectral similarity coefficients of the visible light band in Examples 1-6 are 0.93-0.95, the spectral similarity coefficients of the near-infrared band are 0.90-0.92, and the spectral similarity coefficients of the 400-2500nm full-band are 0.91-0.93, indicating that the military-grade biomimetic camouflage coating of the present invention can simultaneously meet the requirements of visible light and near-infrared compatibility. The principle is that the selected pigments (pigments) are specially designed to have visible light absorption characteristics and near-infrared reflection characteristics similar to natural vegetation (such as trees, woodlands, grasslands, swamps, etc.). In the visible light band, the color of the pigment is consistent with that of natural vegetation; in the near-infrared band, the reflectivity of the pigment is similar to that of natural vegetation, thus achieving compatibility between visible light and near-infrared. The biomimetic fillers (wood chips, grass chips) have irregular shapes and size distributions (particle size 0.1-2mm), and during the coating curing process, they are randomly distributed on the surface and inside of the coating, forming an uneven textured structure. This textured structure creates a three-dimensional visual effect, presenting an appearance similar to natural vegetation, further enhancing the biomimetic effect.

[0048] In summary, the military-grade biomimetic camouflage coating of the present invention achieves unexpected technical effects through the following technical means: it not only achieves camouflage compatible with visible light and near-infrared light, enhancing the visual three-dimensional effect of the coating and obtaining a high degree of biomimetic effect; it also improves the coating's comprehensive performance in terms of water resistance, salt spray resistance, weather resistance, and aging resistance.

[0049] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or use similar methods to replace the specific embodiments described, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A biomimetic camouflage coating for military use, characterized in that, The components include the following parts by weight: Acrylic resin: 20-25 parts; Hydroxyacrylate resin: 10-15 parts; Environmentally friendly solvent: 4-10 parts; Defoamer: 0.3-0.5 parts; Leveling agent: 0.4-0.7 parts; Catalyst: 0.01-0.02 parts; Ultraviolet light absorber: 0.5-1.0 parts; UV-blocking stabilizer: 0.5-1.0 parts; Filler: 25-35 parts; Pigment: 25-30 parts; Bionic filler: appropriate amount.

2. The military-grade biomimetic camouflage coating according to claim 1, characterized in that, The acrylic resin is MACRYNAL SM516 / 70BAC, with a solid content of 70% and a hydroxyl value of 120 mg KOH / g; the hydroxyl acrylic resin is CTR-6225, with a solid content of 60% and a hydroxyl value of 100 mg KOH / g.

3. The military-grade biomimetic camouflage coating according to claim 1, characterized in that, The environmentally friendly solvent is propylene glycol methyl ether acetate and / or butyl alkyd; the ultraviolet light absorber is Tinuvin 1130, and the ultraviolet light blocking stabilizer is Tinuvin 292.

4. The military-grade biomimetic camouflage coating according to claim 1, characterized in that, The filler is talc powder with a particle size of 5-15μm and a whiteness of ≥90%.

5. The military-grade biomimetic camouflage coating according to claim 1, characterized in that, The pigment is a color paste, including various color pastes used to simulate the colors of natural vegetation such as trees, woodlands, grasslands, and swamps.

6. The military-grade biomimetic camouflage coating according to claim 1, characterized in that, The biomimetic filler is wood chips and / or grass chips with a particle size of 0.1-2 mm and an irregular shape, used to mimic the texture and surface morphology of natural vegetation.

7. The military-grade biomimetic camouflage coating according to claim 1, characterized in that, It also includes a curing agent, which is a polyisocyanate curing agent, and is added at 5-10% of the weight of the coating.

8. The method for preparing military-grade biomimetic camouflage coating as described in any one of claims 1-7, characterized in that, Includes the following steps: (1) Add acrylic resin, hydroxy acrylic resin, environmentally friendly solvent, defoamer and leveling agent to a mixing container and stir at 400-500 rpm for 10-15 minutes to obtain mixture A; (2) Add pigment, catalyst, ultraviolet light absorber and ultraviolet light blocking stabilizer to mixture A, and stir at high speed to obtain mixture B; (3) Add filler to mixture B and stir at 800-1000 rpm for 15-20 minutes to obtain mixture C; (4) Add biomimetic filler to mixture C and stir at low speed for 10-15 minutes; (5) Filter the mixture D to remove impurities, and package it to obtain the military biomimetic camouflage coating.

9. The preparation method according to claim 8, characterized in that, The high-speed stirring speed in step (2) is 1200-1500 rpm, and the stirring time is 20-30 minutes; the low-speed stirring speed in step (4) is 300-500 rpm.

10. The preparation method according to claim 8, characterized in that, It also includes the step of mixing the coating with a curing agent before application, wherein the curing agent is a polyisocyanate curing agent, and the amount added is 5-10% of the weight of the coating.

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