Coating for explosion-proof vehicle

Abstract

The invention belongs to the technical field of vehicle protection materials, and particularly relates to a coating for an explosion-proof vehicle. The coating is composed of an adhesion bottom layer, an energy-absorbing middle layer and an anti-impact outer layer, wherein the adhesion bottom layer contains epoxy resin and flaky zinc powder / mica powder, and a laminated shielding structure is formed to improve the adhesion force to be larger than or equal to 8 MPa; the energy-absorbing middle layer is a composite material of modified nano silicon dioxide / polyethylene glycol-based STF and silanized aramid fiber, the viscosity of the energy-absorbing middle layer is sharply increased by more than 50 times at the strain rate of 500s <-1 >, and 65% of explosion impact energy can be absorbed; the anti-impact outer layer adopts a polyurea elastomer to wrap gradient distribution silicon carbide microspheres, pyramid-shaped protrusions are designed on the surface, the fragment defense speed reaches 430 m / s, and the shock wave reflection dispersion is increased by 50%. The whole anti-explosion coating passes UL94V-0 certification through a synergistic flame-retardant system, the chemical protection and self-cleaning capacity is improved through a super-hydrophobic surface layer, and the problems that a traditional anti-explosion coating is poor in adhesive force, weak in composite threat resistance and insufficient in environmental adaptability are solved.

Description

Technical Field

[0001] This invention relates to the field of vehicle protective materials technology, and more specifically, to a coating for explosion-proof vehicles. Background Technology

[0002] Explosion-proof vehicles play a crucial protective role in modern counter-terrorism operations, VIP escort, and hazardous materials transportation. According to the *Global Defence Report 2023*, global demand for explosion-proof vehicles has increased by 17.2% in the past five years. The combined threat of blast waves and high-speed fragments constitutes the main kill mechanism. Traditional solutions rely on increasing the thickness of armor steel plates (typically ≥15mm), leading to an increase in vehicle weight of over 40%, severely sacrificing mobility and fuel efficiency. Coating protection technology has become a research hotspot due to its lightweight potential, but existing coatings face significant technical bottlenecks in terms of blast wave resistance, flame retardancy, and environmental adaptability. Current technologies still have certain shortcomings:

[0003] 1. Adhesion and impact resistance are mutually exclusive.

[0004] Although conventional epoxy-based anti-corrosion coatings have an adhesion strength of ≥5MPa, they are prone to large-area peeling under explosive impact. Experiments show that when subjected to a 0.3ms pulse width shock wave, the coating peels off more than 60% of its area. This is because the lack of lamellar filler leads to stress transmission failure, preventing the formation of an effective energy dissipation path.

[0005] 2. Single-layer structures are ill-equipped to cope with complex threats.

[0006] While mainstream polyurea elastomer coatings possess high elongation (≥300%), their fragmentation protection limit is only 280 m / s (1.8g steel fragment), and they lack strain rate strengthening effects. In a 12kg TNT equivalent explosion test, the deformation of the backplate in a single-layer structure exceeded the safety threshold by 45 mm, and due to the lack of a gradient impedance matching layer, the shock wave energy absorption rate was less than 40%.

[0007] 3. Limited functionality leads to poor battlefield adaptability.

[0008] Existing explosion-proof coatings generally neglect the requirements for chemical protection and self-cleaning. Tests show that when phosphorus-containing agent droplets come into contact with commercially available explosion-proof coatings, the penetration depth reaches 80μm within 30 minutes; and on rough surfaces (Ra=25μm), the amount of dirt adhering to the surface in a dusty environment is ≥120g / m². 2 / week, the extra weight reduces vehicle mobility, and frequent decontamination operations increase the risk of exposure.

[0009] Therefore, a coating for explosion-proof vehicles is proposed to address the above problems. Summary of the Invention

[0010] In order to overcome the above-mentioned defects of the prior art, embodiments of the present invention provide a coating for explosion-proof vehicles to solve the problems mentioned in the background art.

[0011] To achieve the above objectives, the present invention provides the following technical solution: a coating for explosion-proof vehicles, comprising an adhesive underlayer, an energy-absorbing intermediate layer, and an impact-resistant outer layer sequentially disposed from the surface of the vehicle body substrate outwards; the adhesive underlayer is composed of an epoxy resin matrix, flake zinc powder, and flake mica powder, wherein the flake zinc powder accounts for 18-28% of the underlayer mass and has an aspect ratio ≥50; the flake mica powder accounts for 6-9% of the underlayer mass and has a flake diameter of 20-40μm, and the two form a laminated shielding structure in the epoxy resin; the energy-absorbing intermediate layer is composed of a shear thickening fluid (STF) and surface-silanized aramid short-cut fibers, the aramid fibers having a length of 1.0-2.5mm and accounting for 10-13% of the volume fraction of the intermediate layer, the layer having a thickness of 2.0-2.8mm, and under dynamic impact testing, the strain rate is ≥500s. -1 When the viscosity increases to more than 50 times the baseline value, the impact-resistant outer layer comprises polyurea elastomer and gradient-distributed ceramic microspheres. The ceramic microspheres are made of silicon carbide with a Mohs hardness ≥9. Microspheres with a particle size of 20-50 μm are concentrated in the inner 50% region of the outer layer, while microspheres with a particle size of 60-100 μm are concentrated in the outer 50% region. The total volume of the microspheres accounts for 30-38%. This layer is 3.0-4.5 mm thick and has pyramidal protrusions on its surface with a depth of 0.3-0.8 mm and a cone angle of 60°-90°, with a protrusion density of 4-6 per cm³. 2 .

[0012] Preferably, the shear-thickening fluid of the energy-absorbing intermediate layer is formed by dispersing nano-silica with an aminosilane-modified surface in polyethylene glycol 400, wherein the mass fraction of nano-silica is 62-68%, the absolute value of the modified Zeta potential is ≥35mV, and the sedimentation rate is ≤5% after standing at 25°C for 72 hours.

[0013] Preferably, the polyurea elastomer is generated by reacting an isocyanate prepolymer with an amino-terminated polyether. The isocyanate prepolymer is prepared by diphenylmethane diisocyanate (MDI) and polytetrahydrofuran ether diol in a ratio of NCO:OH = 2.2:1. The amino-terminated polyether is polypropylene triamine with a molecular weight of 2000. The reaction equivalence ratio of the two is NCO:NH2 = 1:0.95-1.05. The final elastomer has a tensile strength ≥25MPa and an elongation at break ≥450%.

[0014] Preferably, each coating contains a specific flame-retardant system, wherein the adhesion underlayer contains 4.5-7.0% triphenyl phosphate and 2.0-3.5% antimony trioxide by mass; the energy-absorbing intermediate layer contains aluminum hydroxide powder with a particle size D50 of 5-8 μm, accounting for 18-22% by mass; and the impact-resistant outer layer contains expandable graphite with an initial expansion temperature of 180-220°C and accounting for 7-10% by mass of the outer layer. Under the synergistic effect of the flame-retardant system, the coating system has passed UL94 V-0 certification.

[0015] Preferably, the surface treatment of the aramid chopped fibers uses γ-aminopropyltriethoxysilane, which increases the interfacial shear strength between the fiber and the STF matrix by 40-60% and reduces fiber pull-out phenomenon by more than 80% under 10J impact energy.

[0016] Preferably, the pyramidal protrusions of the impact-resistant outer layer are arranged in a hexagonal close-packed array, with the top of the protrusion being a spherical surface with a radius of curvature of 0.1-0.3 mm. Adjacent protrusions are connected by grooves with a depth of 0.1-0.2 mm. This structure increases the dispersion of the explosion shock wave reflection angle by 35-50%.

[0017] Preferably, it also includes a hydrophobic functional layer disposed on the surface of the impact-resistant outer layer. This layer is formed by hydrolysis and condensation of perfluorooctyltriethoxysilane and methyltrimethoxysilane in a 3:1 molar ratio, with a thickness of 5-15 μm, a static water contact angle ≥152°, a roll-off angle ≤5°, and a contact angle attenuation rate ≤3% after 500 washes.

[0018] Preferably, the adhesion between the adhesive underlayer and the vehicle body substrate is ≥8MPa, the energy absorption rate of the energy-absorbing intermediate layer under a 0.3ms pulse width explosive shock wave is ≥65%, and the impact-resistant outer layer can withstand the penetration of 1.8g cubic fragments at a speed of 420m / s.

[0019] A method for preparing a coating for explosion-proof vehicles, comprising:

[0020] Adhesion undercoating: Epoxy resin E-44, flake zinc powder, flake mica powder and flame retardant are mixed and dispersed at 60℃ to a fineness of ≤30μm. After adding polyamide curing agent, the mixture is roller coated onto the vehicle body and cured at 80℃ for 1 hour to form an 80-120μm coating.

[0021] Energy-absorbing intermediate layer molding: Modified nano silica and polyethylene glycol 400 are dispersed in a high-speed emulsifier at 5000 rpm for 30 minutes. After adding surface-treated aramid fibers, vacuum degassing is performed. The mixture is then coated onto the bottom layer and cured in an environment of 25℃ and ≤40% humidity for 24 hours.

[0022] Impact-resistant outer layer construction: The polyurea prepolymer containing gradient ceramic microspheres is coated by molding texture roller and cured at 40°C for 3 hours to form the specified surface structure.

[0023] An explosion-proof vehicle using the aforementioned coating has a total coating thickness of ≥8mm in the chassis area, wherein the energy-absorbing intermediate layer accounts for 40-45%; the proportion of ceramic microspheres with a particle size of 60-100μm in the impact-resistant outer layer in the side area of ​​the vehicle body is increased to 55-60%; and a hydrophobic functional layer is added to the roof area and a silane curing agent is sprayed on monthly.

[0024] The technical effects and advantages of this invention are as follows:

[0025] Compared with existing technologies, this invention achieves highly efficient explosion protection through a three-layer composite structure: the adhesion bottom layer uses sheet metal and mica powder to form a layered shielding structure in an epoxy matrix, significantly improving the interfacial bonding strength and anti-peeling ability of the coating and the vehicle body; the energy-absorbing middle layer utilizes the strain rate sensitive characteristics of shear-thickening fluid and short-cut fibers to trigger a surge in fluid viscosity and activate the fiber bridging effect at the moment of explosion, efficiently dissipating shock wave energy; the impact-resistant outer layer uses gradient-distributed hard ceramic microspheres and a customized surface texture design to cause high-speed fragments to undergo multi-level deflection and fragmentation during penetration, while guiding the discretization of the shock wave reflection path; combined with a layered flame-retardant system and a superhydrophobic functional layer, it simultaneously solves the problems of flame spread suppression and self-cleaning of chemical pollutants, achieving all-dimensional protection against explosion shock waves, fragment penetration, flame combustion, and battlefield corrosive environments while ensuring the lightweight of the entire vehicle. Attached Figure Description

[0026] Figure 1 This is a system framework diagram of the present invention.

[0027] Figure 2 This is a flowchart of the process of the present invention.

[0028] Figure 3 This is a functional coordination diagram of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1:

[0031] As attached Figure 1-3As shown, (1) a coating for explosion-proof vehicles, comprising an adhesive underlayer, an energy-absorbing intermediate layer, and an impact-resistant outer layer arranged sequentially from the surface of the vehicle body substrate outwards; the adhesive underlayer is composed of an epoxy resin matrix, flake zinc powder, and flake mica powder, wherein the flake zinc powder accounts for 18-28% of the underlayer mass and has a diameter-to-thickness ratio ≥50; the flake mica powder accounts for 6-9% of the underlayer mass and has a flake diameter of 20-40μm, and the two form a laminated shielding structure in the epoxy resin; the energy-absorbing intermediate layer is composed of a shear thickening fluid (STF) and surface-silanized aramid short-cut fibers, the aramid fibers having a length of 1.0-2.5mm and accounting for 10-13% of the volume fraction of the intermediate layer, the layer having a thickness of 2.0-2.8mm and a strain rate ≥500s under dynamic impact testing. -1 When the viscosity increases to more than 50 times the baseline value, the impact-resistant outer layer comprises polyurea elastomer and gradient-distributed ceramic microspheres. The ceramic microspheres are made of silicon carbide with a Mohs hardness ≥9. Microspheres with a particle size of 20-50 μm are concentrated in the inner 50% region of the outer layer, while microspheres with a particle size of 60-100 μm are concentrated in the outer 50% region. The total volume of the microspheres accounts for 30-38%. This layer is 3.0-4.5 mm thick and has pyramidal protrusions on its surface with a depth of 0.3-0.8 mm and a cone angle of 60°-90°, with a protrusion density of 4-6 per cm³. 2 The adhesive underlayer uses epoxy resin E-44 as the matrix, mixed with flake zinc powder (22% by mass) with an aspect ratio ≥50:1 and flake mica powder (7% by mass) with a flake diameter of 30μm, and dispersed at high speed to a fineness ≤25μm to form a slurry; the energy-absorbing intermediate layer consists of 1.5mm long aramid fibers (12% by volume) pre-impregnated in nano-silica / PEG400 type STF (65% by mass of silica), and coated into a 2.5mm thick coating. Testing showed that it could withstand 800 seconds of light exposure. -1 The viscosity increased 58-fold under strain rate; the impact-resistant outer layer consisted of MDI-based polyurea encapsulating gradient-distributed silicon carbide microspheres (40% of the inner area consisted of 30μm microspheres, and 60% of the outer area consisted of 80μm microspheres, accounting for 35% of the total volume), which were formed by pressing with a pyramidal textured mold to achieve a depth of 0.5mm, a cone angle of 75°, and a density of 5 microspheres / cm³. 2 The surface structure has a total thickness of 4.0 mm.

[0032] (2) The shear-thickening fluid of the energy-absorbing intermediate layer is formed by dispersing nano-silica with aminosilane modified on the surface in polyethylene glycol 400, wherein the mass fraction of nano-silica is 62-68%, the absolute value of the zeta potential after modification is ≥35mV, and the sedimentation rate is ≤5% after standing at 25℃ for 72 hours. The nano-silica is modified by γ-aminopropyltriethoxysilane (1.2% of the mass of silica) in ethanol solution for 2 hours, and the zeta potential after modification reaches -38mV. The modified particles are added to PEG400 at 60℃ and dispersed at 5500rpm for 40 minutes to obtain STF with a sedimentation rate of only 3.8% after standing at 25℃ for 72 hours. When used to impregnate aramid fibers, it exhibits a uniform coating state.

[0033] (3) The polyurea elastomer is generated by reacting an isocyanate prepolymer with a terminal amino polyether. The isocyanate prepolymer is prepared by reacting diphenylmethane diisocyanate (MDI) and polytetrahydrofuran ether diol in a ratio of NCO:OH = 2.2:1. The terminal amino polyether is polypropylene triamine with a molecular weight of 2000. The reaction equivalence ratio of the two is NCO:NH2 = 1:0.95-1.05. The final elastomer has a tensile strength ≥25MPa and an elongation at break ≥450%. The isocyanate prepolymer is synthesized by reacting MDI and polytetrahydrofuran ether diol (molecular weight 2000) at 80℃ for 3 hours with an NCO:OH ratio of 2.2:1 (NCO content 8.5%). The terminal amino polyether is Jeffamine. T-5000 (molecular weight 5000) is mixed with prepolymer in a two-component spraying equipment at an equivalent ratio of NCO:NH2 = 1:1.02. After the reaction, the elastomer has a tensile strength of 28MPa (GB / T 528) and an elongation at break of 480% (GB / T 529).

[0034] (4) Each coating contains a specific flame-retardant system. The adhesion base layer contains 4.5-7.0% triphenyl phosphate and 2.0-3.5% antimony trioxide by mass; the energy-absorbing intermediate layer contains aluminum hydroxide powder with a particle size of D50 = 5-8μm, accounting for 18-22% by mass; and the impact-resistant outer layer contains expandable graphite with an initial expansion temperature of 180-220℃, accounting for 7-10% by mass. Under the synergistic effect of the flame-retardant system, the coating system has passed UL94 V-0 certification. Specifically, the adhesion base layer contains 6% triphenyl phosphate and 2.5% antimony trioxide; the energy-absorbing intermediate layer contains aluminum hydroxide powder with a D50 = 6μm (accounting for 20% by mass); and the impact-resistant outer layer contains 9% expandable graphite (initial expansion temperature 200℃). After the three-layer coating is composited, it is tested by UL94: the flame tip height is ≤30mm when burning vertically, the afterflame time is 0s, and the drippings do not ignite degreased cotton, meeting the V-0 standard.

[0035] (5) The surface treatment of the aramid chopped fibers uses γ-aminopropyltriethoxysilane. The interfacial shear strength between the treated fibers and the STF matrix is ​​increased by 40-60%, and the fiber pull-out phenomenon is reduced by more than 80% under 10J impact energy. Specifically, the aramid fibers are ultrasonically treated in an acetone solution containing 0.8% γ-aminopropyltriethoxysilane for 30 minutes, dried, and then composited with STF. The interfacial shear strength was increased from 18MPa to 26MPa (an increase of 44%) by microdroplet debonding test; the drop hammer impact test (10J energy) showed that the fiber pull-out rate decreased from 35% to 6%.

[0036] (6) The impact-resistant outer layer features pyramidal protrusions arranged in a hexagonal close-packed array. The tops of the protrusions are spherical surfaces with a radius of curvature of 0.1-0.3 mm. Adjacent protrusions are connected by grooves with a depth of 0.1-0.2 mm. This structure increases the dispersion of the explosion shock wave reflection angle by 35-50%. Specifically, an uncured polyurea coating is pressed using a hexagonal close-packed array mold, the tops of the protrusions are machined into spherical surfaces with a radius of curvature of 0.2 mm, and V-shaped grooves with a depth of 0.15 mm are etched between adjacent protrusions. Explosion tests (1 kg TNT / 3 m distance) show that compared to a flat surface, this structure reduces the peak shock wave pressure by 42% and the reflection angle dispersion by 48% (high-speed photography analysis).

[0037] (7) It also includes a hydrophobic functional layer disposed on the surface of the impact-resistant outer layer. This layer is formed by the hydrolysis and condensation of perfluorooctyltriethoxysilane and methyltrimethoxysilane in a 3:1 molar ratio, with a thickness of 5-15 μm, a static water contact angle ≥152°, a roll-off angle ≤5°, and a contact angle attenuation rate ≤3% after 500 washes. Specifically, perfluorooctyltriethoxysilane and methyltrimethoxysilane are dissolved in an ethanol / water mixture (pH=4) in a 3:1 molar ratio, hydrolyzed for 30 minutes, and then sprayed onto the impact-resistant outer layer. It is then cured at 120°C to form a 10 μm thick hydrophobic layer. The contact angle test (GB / T 30447) shows a static angle of 155°±2° and a roll-off angle of 4°; after 500 tests using a reciprocating scrubbing machine (ASTM D2486), the contact angle remains at 152°.

[0038] (8) The adhesion between the adhesive underlayer and the vehicle body substrate is ≥8MPa, the energy absorption rate of the energy-absorbing intermediate layer under a 0.3ms pulse width explosive shock wave is ≥65%, and the impact-resistant outer layer can resist the penetration of 1.8g cubic fragments at a speed of 420m / s. Among them, the adhesion of the adhesive underlayer reaches 9.3MPa in the cross-cut test (GB / T 9286); the energy absorption rate of the energy-absorbing intermediate layer against the 0.3ms pulse width shock wave in the explosion test (GJB 5891-2006) is 68%; the impact-resistant outer layer successfully resists the vertical penetration of 1.8g cubic steel fragments at a speed of 430m / s (±5%) in the fragment test, and the back convex height is ≤2mm.

[0039] (9) A method for preparing a coating for explosion-proof vehicles, comprising:

[0040] Adhesion undercoating: Epoxy resin E-44, flake zinc powder, flake mica powder and flame retardant are mixed and dispersed at 60℃ to a fineness of ≤30μm. After adding polyamide curing agent, the mixture is roller coated onto the vehicle body and cured at 80℃ for 1 hour to form an 80-120μm coating.

[0041] Energy-absorbing intermediate layer molding: Modified nano silica and polyethylene glycol 400 are dispersed in a high-speed emulsifier at 5000 rpm for 30 minutes. After adding surface-treated aramid fibers, vacuum degassing is performed. The mixture is then coated onto the bottom layer and cured in an environment of 25℃ and ≤40% humidity for 24 hours.

[0042] Impact-resistant outer layer construction: The polyurea prepolymer containing gradient ceramic microspheres is coated by a molding textured roller and cured at 40℃ for 3 hours to form the specified surface structure. Adhesion underlayer construction: Epoxy resin E-44, 22% flake zinc powder, 7% mica powder, 6% triphenyl phosphate, and 2.5% antimony trioxide are mixed at 60℃, processed to a fineness of 28μm using a three-roll mill, and then coated with 35% polyamide curing agent 650 by roller coating. The coating is baked at 80℃ for 1 hour to form a 100μm coating. Energy-absorbing intermediate layer construction: Modified STF and treated aramid fibers are degassed in a vacuum reactor for 20 minutes, then scraped and cured at 25℃ / 35%RH for 24 hours. Impact-resistant outer layer construction: The polyurea prepolymer containing gradient ceramic microspheres is coated by a roller with a hexagonal array texture (linear pressure 80N / cm) and cured at 40℃ for 3 hours.

[0043] (10) An explosion-proof vehicle using the coating described above, wherein the total coating thickness in the chassis area is ≥8mm, wherein the energy-absorbing intermediate layer accounts for 40-45%; the proportion of ceramic microspheres with a particle size of 60-100μm in the impact-resistant outer layer in the side area of ​​the vehicle body is increased to 55-60%; a hydrophobic functional layer is added to the roof area and a silane curing agent is sprayed on monthly, wherein the total coating thickness in the chassis area of ​​the explosion-proof vehicle is 8.5mm (adhesion layer 0.1mm + energy-absorbing layer 3.6mm + impact-resistant layer 4.8mm), and the energy-absorbing layer accounts for 42.4%; the distribution of ceramic microspheres in the side area of ​​the vehicle body is adjusted, with 80μm microspheres accounting for 58% in the outer area; a hydrophobic functional layer is sprayed on the roof outside the impact-resistant layer, and a curing agent containing 5% perfluorosilane is sprayed on monthly (spraying amount 15g / m²). 2 ).

[0044] Example 2: Multi-source data joint modeling scenario

[0045] Step 1: Pretreatment of vehicle body substrate

[0046] (1) Sandblasting: Use No. 16 brown corundum gravel (particle size 1.2-1.8mm) to blast the surface of the vehicle body at a pressure of 0.7MPa until the surface roughness reaches Sa 2.5 (visual inspection: uniform grayish-white metal matrix, no oxide scale residue).

[0047] (2) Solvent cleaning: Wipe the surface twice with an acetone-isopropanol mixture (volume ratio 3:1). After evaporation and drying, the residual grease on the substrate surface should be ≤10mg / m³. 2 (Tested according to GB / T 13312)

[0048] Principle: Sandblasting creates a micro-anchoring structure to enhance adhesion; solvent cleaning eliminates coating defects.

[0049] Step 2: Preparation and application of the adhesive underlayer

[0050] 1. Formula calculation (based on 100kg of mixed liquid):

[0051] Epoxy resin E-44: 100 × (1 - 0.22 - 0.07 - 0.085) = 63.5 kg;

[0052] Zinc flake powder (aspect ratio ≥ 50:1): 100 × 0.22 = 22 kg;

[0053] Flake mica powder (flake diameter 30±5μm): 100×0.07=7kg;

[0054] Triphenyl phosphate flame retardant: 100 × 0.06 = 6 kg;

[0055] Antimony trioxide synergist: 100 × 0.025 = 2.5 kg;

[0056] 2. Mixing and dispersing: Put the above materials into a preheated reactor at 60℃, stir at 1200rpm for 20 minutes, and circulate them 3 times through a three-roll mill until the fineness is ≤30μm as measured by a fineness gauge (the scraper fineness gauge shall conform to GB / T1724).

[0057] 3. Curing process: After adding polyamide curing agent 650 (dosage = epoxy resin mass × 35%), roll coat and cure in an 80℃ oven for 1 hour. The film thickness should be controlled at 100±10μm (calibrated with a magnetic thickness gauge).

[0058] The key control point is that if the fineness is not up to standard, additional grinding is required; if the curing is insufficient, the baking time can be extended until there is no white line when scratched with a fingernail.

[0059] Step 3: Preparation and molding of the energy-absorbing intermediate layer

[0060] (1) STF fluid synthesis

[0061] Nano silica modification: 10 kg of nano SiO2 (particle size 20 nm) was added to an ethanol solution (concentration 5%) containing 0.12 kg of γ-aminopropyltriethoxysilane, sonicated for 30 minutes, and centrifuged and dried. The zeta potential was measured to be -38 mV.

[0062] STF preparation: Modified SiO2 and PEG400 are mixed at a mass ratio of 65:35, emulsified at 60℃ and 5000rpm for 40 minutes, and the sedimentation rate is ≤5% after standing for 72 hours to be qualified.

[0063] (2) Aramid fiber treatment

[0064] Aramid fibers with a length of 1.5 mm were immersed in an acetone solution containing 0.8% silane coupling agent, sonicated at 60°C for 30 minutes, and then dried.

[0065] Interface strength verification: A single fiber was embedded with an STF microdroplet, and the interfacial shear strength was tested to be ≥25MPa.

[0066] (3) Composite coating construction

[0067] Add the treated aramid fiber to STF at a volume ratio of 12%, and degas under vacuum for 15 minutes (-0.095MPa);

[0068] Apply to the adhesive substrate with a thickness of 2.5±0.2mm (control the blade gap), and cure at 25℃ / 35%RH for 24 hours;

[0069] Performance verification: A 10×10cm sample was subjected to drop hammer impact (10J energy), and the indentation depth of the back substrate was ≤1.5mm.

[0070] Step 4: Construction of the impact-resistant outer layer

[0071] (1) Synthesis of polyurea prepolymer: using a prepolymerization reaction: diphenylmethane diisocyanate (MDI) and polytetrahydrofuran ether diol (molecular weight 2000) are mixed at NCO:OH = 2.2:1 and reacted at 80°C for 3 hours until the NCO content is 8.5±0.2%.

[0072] Elastomer generation: The prepolymer and amino-terminated polyether T-5000 are instantaneously mixed in the spraying equipment at an equivalent ratio of NCO:NH2 = 1:1.02.

[0073] (2) Realization of gradient distribution of ceramic microspheres

[0074] Inner layer slurry: polyurea matrix + 30μm silicon carbide microspheres (occupying 35% of the area volume);

[0075] Outer slurry: polyurea matrix + 80μm silicon carbide microspheres (accounting for 58% of the area volume);

[0076] Gradient construction: First, spray the inner layer of slurry to a thickness of 2mm, and then apply the outer layer of slurry within 3 minutes;

[0077] (3) Surface texture forming

[0078] Use a hexagonal close-packed pyramidal mold (protrusion height 0.5mm, cone angle 75°) to roll with a linear pressure of 80N / cm.

[0079] After curing at 40℃ for 3 hours, the product was demolded. The density of raised bumps was measured to be 5 ± 0.3 bumps / cm². 2 (Projector counting method). Fragmentation protection test: According to GJB 5891-2006, 1.8g cubic steel fragments are fired at 430±5m / s, and the back convexity height is ≤2mm to be considered qualified.

[0080] Step 5: Applying the hydrophobic functional layer

[0081] Solution preparation: Perfluorooctyltriethoxysilane:methyltrimethoxysilane = 3:1 (molar ratio) dissolved in ethanol / water (9:1), pH adjusted to 4.0 with acetic acid, and hydrolyzed for 30 minutes.

[0082] Spraying process: 0.3MPa airless spraying, wet film thickness 15μm → 120℃ curing for 20 minutes → dry film thickness 10±1μm.

[0083] Durability maintenance: Apply a protective agent containing 5% perfluorosilane monthly (15g / m²). 2 After 500 wash cycles, the contact angle decay is ≤3%.

[0084] Step 6: Vehicle-wide zone painting scheme

[0085]

[0086] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.

[0087] Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0088] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A coating for an explosion-proof vehicle, characterized by, The application relates to a multilayered impact-resistant coating for vehicle bodywork, comprising, from the surface of the bodywork substrate outward, an adhesive primer layer, an energy-absorbing intermediate layer and an impact-resistant outer layer; the adhesive primer layer is composed of an epoxy resin matrix, flaky zinc powder and flaky mica powder, wherein the flaky zinc powder accounts for 18-28% of the mass of the primer layer and has a diameter-thickness ratio of greater than or equal to 50:1, the flaky mica powder accounts for 6-9% of the mass of the primer layer and has a flake diameter of 20-40 mu m, and the two form a laminated shielding structure in the epoxy resin; the energy-absorbing intermediate layer is composed of a shear thickening fluid (STF) and surface silanization-treated aramid short fibers, the aramid fiber length is 1.0-2.5 mm, and the aramid fiber accounts for 10-13% of the volume fraction of the intermediate layer; the thickness of the intermediate layer is 2.0-2.8 mm, the viscosity of the intermediate layer rises to more than 50 times the base value at a strain rate of greater than or equal to 500 s -1 -1, and the dynamic impact test is carried out; and the impact-resistant outer layer is composed of a polyurea elastomer and gradient-distributed ceramic microspheres, wherein the ceramic microspheres are made of silicon carbide with a Mohs hardness of greater than or equal to 9, the particle size of the 20-50 mu m microspheres is concentrated in the inner 50% area of the outer layer, the particle size of the 60-100 mu m microspheres is concentrated in the outer 50% area of the outer layer, the total volume fraction of the microspheres is 30-38%, the thickness of the outer layer is 3.0-4.5 mm, and the surface of the outer layer has pyramid-shaped protrusions with a depth of 0.3-0.8 mm and a cone angle of 60-90 degrees, and the protrusion density is 4-6 per cm 2 .

2. A coating for an explosion-proof vehicle according to claim 1, characterized in that: The shear thickening fluid of the energy-absorbing intermediate layer is formed by dispersing surface amino-silane modified nano-silica in polyethylene glycol 400, wherein the mass fraction of nano-silica is 62-68%, the absolute value of Zeta potential after modification is ≥35 mV, and the sedimentation rate after standing for 72 hours at 25℃ is ≤5%.

3. A coating for an explosion-proof vehicle according to claim 1, characterized in that: The polyurea elastomer is formed by the reaction of isocyanate prepolymer and amino-terminated polyether, wherein the isocyanate prepolymer is prepared from diphenylmethane diisocyanate (MDI) and polytetrahydrofuran ether diol with a ratio of NCO:OH=2.2:1, the amino-terminated polyether is polypropylene oxide triamine with a molecular weight of 2000, and the equivalent ratio of NCO:NH2 is 1:0.95-1.05, and the final elastomer has a tensile strength ≥25 MPa and an elongation at break ≥450%.

4. A coating for an explosion-proof vehicle according to claim 1, characterized in that: Each coating layer contains a specific flame-retardant system, wherein the adhesive bottom layer is added with triphenyl phosphate accounting for 4.5-7.0% of its mass and antimony trioxide accounting for 2.0-3.5% of its mass; the energy-absorbing intermediate layer is added with aluminum hydroxide powder with a particle size D50=5-8 μm, accounting for 18-22% of its mass; and the impact-resistant outer layer is added with expandable graphite with an initial expansion temperature of 180-220℃ and accounting for 7-10% of the mass of the outer layer, and the coating system passes the UL94 V-0 level certification through the synergistic effect of the flame-retardant system.

5. A coating for an explosion-proof vehicle according to claim 2, characterized in that: The surface treatment of the aramid short-cut fiber uses γ-aminopropyl triethoxysilane, and the interface shear strength between the treated fiber and the STF matrix is increased by 40-60%, and the fiber pull-out phenomenon is reduced by more than 80% under an impact energy of 10 J.

6. A coating for an explosion-proof vehicle according to claim 1, characterized in that: The pyramidal protrusions of the impact-resistant outer layer are arranged in a hexagonal close-packed array, the top of the protrusions is a spherical surface with a radius of curvature of 0.1-0.3 mm, and adjacent protrusions are connected by grooves with a depth of 0.1-0.2 mm, and this structure increases the dispersion degree of the reflection angle of the blast shock wave by 35-50%.

7. A coating for an explosion-proof vehicle according to claim 1, characterized in that: It also includes a hydrophobic functional layer arranged on the surface of the impact-resistant outer layer, which is formed by hydrolytic condensation of perfluorooctyl triethoxysilane and methyl trimethoxysilane at a molar ratio of 3:1, with a thickness of 5-15 μm, a static water contact angle ≥152°, a rolling angle ≤5°, and a contact angle attenuation rate ≤3% after 500 times of washing.

8. A coating for an explosion-proof vehicle according to claim 1, characterized in that: The adhesive force between the adhesive bottom layer and the vehicle body substrate is ≥8 MPa, the energy absorption rate of the energy-absorbing intermediate layer under a 0.3 ms pulse width blast shock wave is ≥65%, and the impact-resistant outer layer can resist 1.8 g cubic fragments penetrating at a speed of 420 m / s.

9. A method for the production of a coating for an explosion-proof vehicle, characterized in that It includes: Adhesive bottom layer coating: mix and disperse epoxy resin E-44, flaky zinc powder, flaky mica powder and flame retardant at 60℃ to a fineness ≤30 μm, add polyamide curing agent, roll coat on the vehicle body, and cure at 80℃ for 1 hour to form a coating layer of 80-120 μm; Energy-absorbing intermediate layer forming: disperse modified nano-silica and polyethylene glycol 400 in a high-speed emulsifier at 5000 rpm for 30 minutes, add surface-treated aramid fiber, vacuum degassing, blade coat on the bottom layer and mature in an environment with a humidity ≤40% at 25℃ for 24 hours; Impact-resistant outer layer construction: polyurea prepolymer containing gradient ceramic microspheres is coated by a textured roll at 40℃ for 3 hours to form a specified surface structure.

10. An explosion-proof vehicle to which the paint for explosion-proof vehicle is applied, characterized by: The total thickness of the vehicle chassis area coating is greater than or equal to 8 mm, wherein the proportion of the energy-absorbing intermediate layer is 40-45%; the proportion of the particle size 60-100 mu m ceramic microspheres in the impact-resistant outer layer of the vehicle body side area is increased to 55-60%; a hydrophobic functional layer is additionally arranged in the roof area and a silane maintenance agent is sprayed every month.

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