Preparation method of waterproof aerogel coating

Abstract

The invention discloses a preparation method of a waterproof aerogel coating, and relates to the technical field of aerogel coatings. According to the invention, a PVA / basalt fiber three-dimensional network is constructed as a strippable skeleton, and the stripping stress is guided to be dissipated in the coating, so that the contradictory characteristics of high adhesion and lossless removal are unified, and by adjusting the ratio of the emulsion to the aerogel, while the excellent waterproof and heat-insulating properties are maintained, the overall stripping is realized, and the thermal insulation performance of the coating is improved. According to the present invention, through the double reinforcement design of strong interface and strong skeleton, the coating is specially used for the ultra-high adhesion and anti-cracking scene, the fluorosilicone system and the weather-resistant auxiliary agent are adopted, the long-acting protection in the extreme outdoor environment is achieved, and the series of the coating provides the solution for the periodic maintenance of the high-value equipment, the historical building and the outdoor facility.

Description

Technical Field

[0001] This invention relates to the field of aerogel coating technology, and more particularly to a method for preparing a waterproof aerogel coating. Background Technology

[0002] Currently, there are various existing technologies for applying aerogels to coatings. For example, using acrylic emulsions as a base, by preparing aerogel dispersions and adding foaming agents, the coating achieves good thermal insulation (a 5mm coating provides a thermal insulation temperature difference of 113.5℃) and adhesion. Another technology uses nano-TiO2 / SiO2 aerogels to modify polymer cement waterproof coatings. The porous structure of the aerogel adsorbs pollutants and provides a site for photocatalysis, while significantly improving the hydrophobicity of the coating, allowing its contact angle to reach over 160°. These technologies generally aim to solve single or combined performance problems related to coatings, such as thermal insulation, waterproofing, or corrosion resistance.

[0003] However, for certain applications requiring periodic maintenance, refurbishment, or extremely high protection of the substrate (such as high-value equipment, historical buildings, and precision instrument enclosures), traditional high-performance protective coatings face a common challenge: the coating is typically designed to have extremely strong and durable adhesion to ensure its protective lifespan. When the coating needs to be removed, the excessive adhesion often makes it difficult to peel off completely, and forced removal can easily damage the substrate surface or leave difficult-to-treat coating residues. Existing technologies mostly focus on how to "enhance" the adhesion and durability of the coating, while rarely addressing how to endow the coating with a "controllable" property that allows for removal without damaging the substrate.

[0004] Therefore, how to provide a controllable method for preparing waterproof aerogel coatings that can be removed without damaging the properties of the substrate is an urgent technical problem to be solved. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method for preparing a waterproof aerogel coating.

[0006] For the purposes described above, the present invention provides A method for preparing a waterproof aerogel coating includes the following steps: S1. Emulsion premixing and plasticizing: Under the conditions of 20-30℃ and relative humidity ≤60%, the silicone-modified acrylic emulsion and the elastic acrylate copolymer emulsion are added to the reaction vessel and stirred and mixed at a speed of 100-130 rpm for 3-5 min. S2. Pre-dispersion of additives: While maintaining stirring, add wetting and dispersing agent, film-forming aid, plasticizer, defoamer and deionized water in sequence, and then increase the stirring speed to 240-260 rpm and disperse at high speed for 12-20 min; S3. Powder premixing and gradient feeding: Dry mix the hydrophobic silica aerogel powder and the intumescent flame retardant for 5-10 min and pass them through an 80-120 mesh sieve. Then, under stirring, add the mixed powder to the system in step S2 in 3-5 batches. The total feeding time is 15-25 min. S4. High-speed shearing homogenization: Switch the agitator to perform multi-stage step shearing on the system in step S3, control the material temperature ≤38℃, until the slurry fineness ≤80 μm, and filter to obtain the base material; S5. Fiber network construction: Adjust the stirring speed to 150-190 rpm, add short-cut basalt fibers and short-cut polyvinyl alcohol fibers in sequence, stir for 18-30 min to fully disperse the fibers and form a three-dimensional network structure with the system; S6. Post-addition, degassing and curing: Add reactive tackifying resin and rheology modifier sequentially under stirring, add defoamer, adjust the total mass of the system with deionized water, then degas under vacuum of -0.085 to -0.095 MPa for 8-12 min, and finally let it stand and cure at 20-30℃ for 90 min-24 h to obtain the waterproof aerogel coating.

[0007] Furthermore, the amount of the silicone-modified acrylic emulsion is 23-33 parts by weight, and the amount of the elastic acrylate copolymer emulsion is 6-8 parts by weight.

[0008] Furthermore, the amount of the hydrophobic silica aerogel powder is 35-45 parts by weight; the intumescent flame retardant is composed of ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 10:(2-4):(2-4).

[0009] Furthermore, the multi-stage stepped shearing includes: a first stage of dispersion at 480-520 rpm for 4-6 min, a second stage of dispersion at 780-820 rpm for 8-12 min, and a third stage of dispersion at 1180-1220 rpm for 5-8 min.

[0010] Furthermore, the length of the chopped basalt fiber is 3-6 mm, and the amount used is 0.3-0.8 parts by weight; the length of the chopped polyvinyl alcohol fiber is 6-10 mm, and the amount used is 0.5-0.7 parts by weight.

[0011] Furthermore, the amount of the reactive tackifying resin is 1.8-2.5 parts by weight, and the amount of the rheology modifier is 0.5-1.0 parts by weight.

[0012] Furthermore, in step S1, the silicone-modified acrylic emulsion is an adhesion-promoting silicone-modified acrylic emulsion, and the elastic acrylate copolymer emulsion is a high tear-resistant elastic emulsion; in step S5, the length of the chopped basalt fiber is 6 mm and the amount is 0.8 parts by mass, the length of the chopped polyvinyl alcohol fiber is 10 mm and the amount is 0.7 parts by mass, and the stirring time for constructing the fiber network is 35-45 min.

[0013] Furthermore, in step S1, the film-forming base material is a fluorosilicone modified acrylic emulsion, and the amount used is 33-37 parts by weight; step S2 also includes adding 0.3-0.7 parts by weight of ultraviolet absorber and 0.2-0.4 parts by weight of light stabilizer; the hydrophobic silica aerogel powder used in step S3 is a hydrophobic silica aerogel powder that has undergone secondary treatment with fluorosilane; and the short-cut polyvinyl alcohol fiber used in step S5 is a hydrolysis-resistant polyvinyl alcohol fiber.

[0014] Furthermore, in step S6, the reactive tackifying resin is a reactive epoxy tackifying resin or a reactive polyurethane tackifying resin.

[0015] The beneficial effects of this invention are: This invention fundamentally alters the coating's damage mechanism by introducing a three-dimensional interpenetrating network constructed from short-cut basalt fibers and polyvinyl alcohol (PVA) fibers as a "peelable skeleton," and coordinating it with hydrophobic aerogel fillers, an elastic emulsion system, and precisely controlled reactive tackifying resins. This fiber network effectively guides and dissipates peel stress, shifting the damage mode from traditional interfacial adhesion damage to cohesive or mixed damage within the coating, thus cleverly reconciling the seemingly contradictory characteristics of "strong adhesion" and "easy overall peeling without damaging the substrate." By adjusting the emulsion-to-aerogel ratio, a gradient design is achieved that balances comprehensive performance, offering high toughness and density or ultra-high thermal insulation while maintaining high adhesion, excellent water resistance, low thermal conductivity, and controllable peelability. Furthermore, a special optimization for super-adhesion crack resistance is conducted. By employing adhesion-promoting emulsions, highly reactive tackifying resins, and longer, more abundant fibers combined with an ultra-long stirring process, a dual-reinforcement system of "strong interface + strong skeleton" is constructed, specifically designed for extreme scenarios requiring high stress and non-destructive replacement. Furthermore, for long-term outdoor protection, a comprehensive weather-resistance upgrade has been implemented. This upgrade utilizes fluorosilicone-modified emulsions, fluorosilane-treated aerogels, UV absorbers, and hydrolysis-resistant fibers, and achieves a stable structure through thorough curing. This allows the coating to maintain excellent protective performance, flexibility, and maintainability even under extreme weather conditions. In summary, this invention, through an innovative coating structure design, has successfully developed a series of coating products that meet diverse needs, from general protection to high-strength and long-lasting applications. It provides a revolutionary coating solution, particularly for the periodic maintenance of high-value equipment, historical buildings, and outdoor infrastructure. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of the preparation process of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0019] Example 1 A method for preparing a waterproof aerogel coating includes the following steps: S1: Emulsion Premixing and Plasticization. This was carried out in a constant temperature and humidity chamber at 25±2°C and 55±5% relative humidity. 28 parts of silicone-modified acrylic emulsion and 8 parts of elastic acrylate copolymer emulsion were sequentially added to a 50L stainless steel reactor equipped with a double-layered, bidirectional anchor-type agitator and a jacketed temperature control system. The silicone-modified acrylic emulsion had a solid content of approximately 50% and a pH of 7.5-8.5; the elastic acrylate copolymer emulsion had a solid content of approximately 55% and a glass transition temperature (Tg) of -15°C. Stirring was started and maintained at 120±10 rpm for 5 minutes to ensure thorough premixing of the two-component emulsion system. The material temperature was maintained ≤35°C throughout the process using circulating cooling water in the jacket.

[0020] S2: Pre-dispersion of additives. Maintaining a stirring speed of 120±10 rpm, the following additives were precisely added sequentially via a metering pump: 0.3 parts by weight of polyether-modified polysiloxane wetting and dispersing agent, 1.2 parts by weight of alcohol ester dodecyl film-forming aid, 1.5 parts by weight of diisononyl phthalate (DINP) plasticizer, 0.2 parts by weight of mineral oil-based defoaming polymer, and 0.8 parts by weight of deionized water for adjusting initial viscosity. After each additive was added, stirring was continued for 2 minutes to ensure initial wetting. Subsequently, the stirring speed was increased to 250±10 rpm, and high-speed dispersion was maintained for 15 minutes to allow the additive molecules to fully diffuse and adsorb in the emulsion phase, completing the secondary plasticization and stabilization of the system.

[0021] S3: Powder Premixing and Gradual Feeding. 40 parts of hydrophobic silica aerogel powder and 16 parts of intumescent flame retardant were added to a three-dimensional conical mixer. The mixture was then dry-mixed at 30 rpm for 10 minutes, followed by sieving through an 80-mesh standard sieve to remove any potential agglomerates. While maintaining the main emulsion system at 250±10 rpm, the mixed powder was divided into four equal batches, added at 5-minute intervals, with the total feeding time controlled within 20 minutes. During the feeding process, it was crucial to ensure the powder was evenly distributed into the center of the liquid vortex to avoid dust generation and localized agglomeration. The specific surface area of ​​the aerogel powder was approximately 650 m². 2 / g, with an average particle size D50 of 15 micrometers and a water contact angle greater than or equal to 145 degrees; the intumescent flame retardant is composed of 10 parts of ammonium polyphosphate with a degree of polymerization of not less than 1000, 3 parts of pentaerythritol and 3 parts of melamine.

[0022] S4: High-speed shearing homogenization. After all powder has been added, the agitator is switched to a serrated disc high-speed dispersion disc. A three-stage stepped shearing process is performed: the first stage disperses at 500±20 rpm for 5 minutes to achieve initial wetting; the second stage increases the dispersion to 800±20 rpm for 10 minutes to break up large particle aggregates; the third stage uses strong shearing at 1200±20 rpm for 6 minutes to achieve ultrafine dispersion. Throughout the process, the material temperature is controlled to ≤38°C using a jacketed cooling system. Samples are taken after each stage and tested using an automatic scraper fineness meter. The dispersion endpoint is defined as when the fineness is consistently ≤80 μm and no particles are visible to the naked eye. After dispersion, the slurry is filtered using a 120-mesh online vibrating filter screen to obtain a uniform and fine base material.

[0023] S5: Fiber Network Construction. Adjust the stirring speed back to 180±10 rpm. First, slowly and evenly sprinkle 0.5 parts by weight of chopped basalt fibers into the system. The fibers are 3 mm long, approximately 13 micrometers in diameter, and have an aspect ratio of approximately 230. Stir for 8 minutes to allow the fibers to initially disperse within the system. Then, slowly add 0.5 parts by weight of chopped polyvinyl alcohol fibers, approximately 6 mm long, approximately 12 micrometers in diameter, and with a water solubility temperature not lower than 80°C. Continue stirring for 20 minutes. This process allows both fibers to fully wet and extend, and to interlock with the polymer emulsion and powder particles, forming a stable, three-dimensional interpenetrating network structure within the coating that effectively transfers and dissipates stress.

[0024] S6: Post-additives, defoaming, and curing. Under medium-speed stirring at 200±10 rpm, the following post-additives were added sequentially: 2.0 parts by weight of reactive epoxy tackifier, with an epoxy equivalent of approximately 450-500 g / eq; followed by 0.8 parts by weight of nonionic polyurethane rheology modifier, the viscosity of which is approximately 3500 mPa·s in a 2% aqueous solution. The nonionic polyurethane rheology modifier was pre-diluted with 3.2 parts by weight of deionized water at a ratio of 1:4 before addition; finally, 0.2 parts by weight of defoamer was added. Stirring was continued for 15 min to ensure uniform mixing. Then, the total mass of the system was accurately brought to 100 parts by weight with deionized water, at which point the solid content of the system was 65±1%. The prepared coating was transferred to a planetary vacuum defoaming mixer and defoamed under a vacuum of -0.09 MPa for 10 min to completely eliminate air bubbles introduced by stirring. After degassing, the coating is immediately sealed and packaged, and then placed in a constant temperature environment of 25°C for 24 hours to mature, thus obtaining the final product.

[0025] Example 2 Based on Example 1, the amount of silicone-modified emulsion in step S1 was changed to 33 parts and the amount of elastic emulsion to 8 parts; the amount of powder added in step S3 was changed to 35 parts; and the other raw material and process steps were the same as in Example 1.

[0026] Example 3 Based on Example 1, the amount of silicone-modified emulsion in step S1 was changed to 23 parts and the amount of elastic emulsion to 8 parts; the amount of powder added in step S3 was changed to 45 parts; and the other raw material and process steps were the same as in Example 1.

[0027] Example 4: Super-adhesion crack-resistant formulation S1: Emulsion premixing and plasticizing. Under conditions of 25±1°C and humidity ≤60%, 30 parts by weight of silicone-modified acrylic emulsion and 6 parts by weight of elastic acrylate copolymer emulsion were added to a 60L frame-type stirred reactor. The silicone-modified acrylic emulsion had a solid content of approximately 55% and was an adhesion-promoting agent; the elastic acrylate copolymer emulsion had a glass transition temperature (Tg) of -8°C and exhibited high tear strength. The mixture was stirred at 115±5 rpm for 4 min, with the temperature controlled at ≤35°C.

[0028] S2: Pre-dispersion of additives. Maintaining a speed of 115±5 rpm, add the following in sequence: 0.3 parts by weight of titanate coupling agent modified wetting and dispersing agent, 1.2 parts by weight of benzyl alcohol film-forming aid, 1.5 parts by weight of polyester plasticizer, 0.2 parts by weight of defoamer, and 1.8 parts by weight of deionized water. Stir for 1 min after each addition. Increase the speed to 260±5 rpm and disperse for 16 min.

[0029] S3: Powder premixing and gradient feeding. 38 parts by weight of hydrophobic silica aerogel powder, 10 parts by weight of ammonium polyphosphate (APP), 3 parts by weight of pentaerythritol (PER), and 3 parts by weight of melamine (MEL) are added and mixed. The specific surface area of ​​the aerogel powder is approximately 620 m². 2 / g. After dry mixing the above materials for 9 minutes, pass them through an 80-mesh standard sieve. Add the mixture in 4 batches at 260±5 rpm, for a total time of 18 minutes.

[0030] S4: High-speed shearing homogenization. A high-linear-velocity dispersing disc was used for shearing at 500 rpm × 5 min, 800 rpm × 10 min, and 1200 rpm × 6 min. Temperature was controlled to ≤37°C. After achieving a particle size ≤80 μm, the material was filtered through a 120-mesh sieve.

[0031] S5: Fiber Network Construction. Reduce the rotation speed to 150±10 rpm. Add 0.8 parts by weight of chopped basalt fibers, 6 mm in length, which are high-modulus type, and then stir for 10 minutes. Next, add 0.7 parts by weight of chopped PVA fibers, 10 mm in length, which have high toughness. Continue vigorous stirring for 35 minutes to greatly enhance the three-dimensional network structure and crack resistance. This step is used for strengthening and toughening. S6: Post-addition, degassing, and curing. Under a stirring speed of 170±10 rpm, 2.5 parts by weight of highly reactive epoxy tackifying resin (epoxy value approximately 0.51) and 0.8 parts by weight of pre-diluted associative polyurethane rheology modifier (HEUR type) were added sequentially, followed by 0.2 parts by weight of defoamer. After continuous stirring for 18 minutes, deionized water was added to bring the total mass of the system to 100 parts by weight, at which point the solid content was approximately 68%. Next, degassing was performed for 9 minutes under a vacuum of -0.09 MPa. Finally, the product was sealed and cured at 25°C for 110 minutes to obtain the super-adhesion crack-resistant coating.

[0032] Example 5: High weather-resistant and flexible formulation S1: Emulsion Premixing. At 23±2°C and 50±5% humidity, 35 parts by weight of fluorosilicone-modified acrylic emulsion were added to a 40-liter corrosion-resistant stirred tank. The emulsion had a solid content of approximately 50%, a fluorine content of not less than 8%, and a QUV aging test time of not less than 2000 hours. The mixture was stirred at a low speed of 120±5 rpm for 5 minutes, with the temperature controlled at ≤34°C.

[0033] S2: Pre-dispersion of additives. Maintaining a speed of 120±5 rpm, add the following in sequence: 0.3 parts by weight of fluorinated wetting and dispersing agent, 1.2 parts by weight of environmentally friendly film-forming aid (Texanol), 2.0 parts by weight of high molecular weight polyadipate plasticizer, 0.5 parts by weight of benzotriazole UV absorber (UV-1130), 0.3 parts by weight of hindered amine light stabilizer (HALS-292), 0.2 parts by weight of defoamer, and 0.7 parts by weight of deionized water. Stir for 2 minutes after each addition. Increase the speed to 245±5 rpm and disperse for 20 minutes.

[0034] S3: Powder premixing and gradient feeding. 40 parts by weight of hydrophobic silica aerogel powder, 10 parts by weight of ammonium polyphosphate, 3 parts by weight of pentaerythritol, and 3 parts by weight of melamine are mixed. The specific surface area of ​​the aerogel powder is approximately 680 m². 2 / g, and underwent secondary treatment with fluorosilane. The above mixture was dry-mixed for 8 minutes and then passed through an 80-mesh standard sieve. It was added in three batches at 245±5 rpm for a total time of 15 minutes.

[0035] S4: High-speed shearing homogenization. Using a high-speed emulsifying shear head, perform shearing at 500 rpm × 5 min, 800 rpm × 10 min, and 1200 rpm × 6 min. Temperature control ≤36°C. Filter after particle size ≤75 μm.

[0036] S5: Fiber Network Construction. Adjust the rotation speed to 175±10 rpm. Add 0.3 parts by weight of chopped basalt fibers, 3 mm in length, of the alkali-resistant type, and stir for 6 minutes to disperse them. Next, add 0.5 parts by weight of chopped polyvinyl alcohol fibers, 6 mm in length, of the hydrolysis-resistant type, and continue stirring for 18 minutes. This enhances the weather resistance and flexibility.

[0037] S6: Post-addition, degassing, and curing. At 185±10 rpm, 2.0 parts by weight of weather-resistant tackifying resin and 0.8 parts by weight of rheology modifier were added for pre-dilution, followed by 0.2 parts by weight of defoamer. After stirring for 12 min, deionized water was added to adjust the total mass of the system to 100 parts by weight, at which point the solid content was approximately 65%. Subsequently, degassing was performed under a vacuum of -0.09 MPa for 8 minutes. After degassing, the product was sealed and cured at 25°C for 96 hours to achieve full cross-linking and obtain a highly weather-resistant product.

[0038] Comparative Example 1: PVA-free fiber network Steps S1-S4 and S6: The raw materials, equipment and process parameters are exactly the same as in Example 1 (B1).

[0039] S5: Fiber Introduction. Reduce the stirring speed to 180±10 rpm, add only 0.5 parts by weight of chopped basalt fiber, stir for 6 minutes, then proceed directly to step S6 without adding PVA fiber. The system lacks a three-dimensional interpenetrating network constructed from PVA fiber. The specifications of the chopped basalt fiber are the same as in Example 1.

[0040] Comparative Example 2: Inelastic Emulsion Components S1: Emulsion premixing and plasticizing. Under the same conditions, add 36 parts by weight of silicone-modified acrylic emulsion (i.e., replace the elastic acrylate copolymer emulsion with 8 parts by weight of the same emulsion) to the stirred tank, and the rest of the operation is the same as B1.

[0041] Steps S2-S6: The raw materials (except for the adjustment in S1), equipment and process parameters are exactly the same as in Example 1 (B1).

[0042] Comparative Example 3: Plasticizer Deficiency Steps S1, S3-S6: The raw materials, equipment and process parameters are exactly the same as in Example 1 (B1).

[0043] S2: Pre-dispersion of additives. While maintaining stirring at 120±10 rpm, add 0.3 parts wetting and dispersing agent, 1.2 parts film-forming aid, 0.2 parts defoamer, and 0.8 parts deionized water sequentially. Do not add plasticizer. After each addition, continue stirring for approximately 1 minute, then increase the stirring speed to 250±10 rpm and stir for 15 minutes.

[0044] Comparative Example 4: Excessive Thickening Steps S1-S5: The raw materials, equipment, and process parameters are exactly the same as in Example 1 (B1).

[0045] S6: Addition of functional additives, degassing, and curing. Under stirring conditions of 200±10 rpm, add 4.0 parts by weight of reactive tackifying resin (replacing 2.0 parts by weight in Example 1), 0.8 parts by weight of rheology modifier (pre-diluted), and the balance 0.2 parts by weight of defoamer. The remaining operations, including water replenishment, degassing, and curing processes, are the same as in B1.

[0046] Comparative Example 5: Defective Process The raw materials and amounts used in steps S1-S3 and S5-S6 are exactly the same as in Example 1.

[0047] S4: Inadequate shearing process. After all powder is added, replace the high-speed dispersing disc, directly increase the rotation speed to 1500±50 rpm and continuously perform strong shearing for 25 minutes, during which the material temperature is controlled to ≤45°C solely by jacket cooling. After shearing, filter through a 120-mesh filter.

[0048] S6: Cure curing. After the coating is degassed for 8 minutes under a vacuum of -0.09 MPa, it is immediately discharged for standby use, without being sealed and allowed to stand for curing.

[0049] Test example: Sample preparation: Using an automated coating machine, the coatings for each embodiment and comparative example were applied in a single coat to two substrates with a wet film thickness of 200 micrometers: one was a standard mortar substrate measuring 150 mm × 70 mm × 4 mm with a roughened surface; the other was a sandblasted steel plate with a surface cleanliness level of Sa 2.5. After coating, the samples were immediately transferred to a constant temperature and humidity curing chamber at 23 ± 1°C and 50 ± 5% relative humidity for 14 days. After curing, a digital coating thickness gauge was used to perform multi-point measurements to ensure that the dry film thickness was controlled within the range of 2.0 ± 0.1 mm.

[0050] Performance testing methods: Adhesion and Failure Mode Analysis: Adhesion testing was conducted using an automatic pull-off method according to GB / T 5210-2006. A specified type of aluminum test column was fixed to the coating surface and a homogeneous substrate using a high-strength two-component epoxy adhesive. After the adhesive was fully cured, a vertical tensile force of 1.0 MPa / s was applied on a universal testing machine until failure. The system automatically recorded the maximum adhesion value (MPa) and automatically captured and analyzed the failure interface using an integrated high-definition camera module. Based on standard spectra, the failure mode was intelligently determined: adhesion failure, cohesive failure, or mixed failure.

[0051] Digital Peel Performance Testing: To quantitatively evaluate the coating's characteristic of "being able to peel off completely without damaging the substrate," a standardized peel test was designed. An automated sample cutter was used to prepare a 20mm wide and 100mm long pre-cut on the cured coating. The sample was fixed to the platform of a universal testing machine, and the peeling end was held by a 90° peeling clamp, peeling was performed at a constant speed of 50mm / min. The machine's sensors recorded the peel force-displacement curve in real time, and the software automatically calculated and reported the average peel force (N / 20mm) during the stable peeling stage. After peeling, a portable 200x digital microscope was used to automatically image and analyze the integrity of the peeled coating strip and the surface morphology of the substrate. Based on a preset algorithm, the peel level was automatically classified into levels I to IV according to the strip continuity and degree of damage.

[0052] Grade I: The coating is completely peeled off without residue, the substrate surface is undamaged, the strip is continuous and complete, the substrate surface is smooth, and there is no coating residue; Grade II: The coating is basically completely peeled off, with slight residue or slight damage to the substrate, the strip is basically continuous, with slight breaks or residue in some areas; Grade III: The coating is not completely peeled off, with obvious residue or damage to the substrate, many broken strips, and residue or slight scratches on the substrate surface; Grade IV: The coating is difficult to peel off, with severe residue or severe damage to the substrate, severe coating breakage during peeling, and obvious residue or damage on the substrate surface. It should be noted that difficulty in peeling does not necessarily mean that substrate residue will remain.

[0053] Water resistance characteristics: Contact angle test: According to GB / T 30693-2014, a fully automatic contact angle measuring instrument is used to automatically distribute 5μL ultrapure water droplets at different positions on the coating surface, calculate the static contact angle by Young-Laplace fitting method, and report the average value of at least 9 measurement points.

[0054] Water absorption test: A free coating of specified thickness was prepared and cut into standard sizes (50mm × 50mm) using a precision automatic die-cutting machine. After drying to constant weight (W0), the sample was completely immersed in deionized water at 23±0.5°C. After 168 hours, it was removed by an automatic sample retrieval and draining system, and after removing surface water using a standard procedure, it was immediately weighed by an analytical balance (W1). The system automatically calculated the water absorption rate: Water absorption rate (%) = [(W1 - W0) / W0] × 100%.

[0055] Thermal conductivity test (characterizing thermal insulation): According to GB / T 10295-2008, a rapid thermal conductivity tester was used to test the prepared homogeneous coated sheet at an average temperature of 25°C, and the thermal conductivity (λ, W / (m·K)) was directly read and recorded.

[0056] Table 1. Test results of key performance of the formulation coating

[0057] Test data show that the coatings in each embodiment of the present invention exhibit excellent comprehensive performance: adhesion between 1.2 and 3.0 MPa, contact angle greater than 118°, water absorption rate less than 3.5%, and thermal conductivity less than 0.045 W / m·K, confirming its basic functional reliability as a waterproof and heat-insulating coating.

[0058] The core innovation is reflected in the peel performance data: the average peel force of all examples is within the suitable range of 10-35 N / 20 mm, and the peel grade is mainly Grade I or Grade I-II. Combined with the failure mode, which is mainly mixed failure or cohesive failure, it verifies that the coating can be removed as an intact film layer under external force. Comparative analysis accurately reveals the mechanism of action of key components: In Comparative Example 1, after the PVA fiber network was missing, the failure mode changed to "adhesion failure as the main factor", and the peel grade dropped to Grade II-III, proving that the three-dimensional fiber network is the key structure for guiding stress dissipation inside the coating and achieving cohesive / mixed failure. Comparative Examples 2 and 3 show that the lack of elastic components or plasticizers will impair the flexibility of the coating, resulting in a decrease in the peel integrity grade. Comparative Example 4 shows that although excessive tackifying resin improves adhesion, it leads to excessive cohesion, excessively high peel force, and severe powdering during peeling (Grade III-IV), which is detrimental to substrate protection, highlighting the crucial importance of balancing and controlling cohesive strength and adhesion.

[0059] Conclusion: This invention uses hydrophobic aerogel as a functional filler, introduces a three-dimensional PVA / basalt fiber network as a release skeleton, combines elastic emulsion and plasticizer to ensure extensibility, and precisely controls the amount of reactive tackifying resin to successfully prepare an innovative protective coating that has high adhesion, excellent waterproof and heat insulation properties, and can achieve overall peeling without damaging the substrate.

[0060] Examples 1-3 of this invention collectively construct a composite coating system with a three-dimensional interpenetrating network of PVA / basalt fibers as the core "peelable skeleton" and hydrophobic aerogel as the functional filler. Through a specific sequence and process, chopped PVA fibers and basalt fibers are sequentially introduced and dispersed in the matrix, forming a stable three-dimensional network within the coating that can effectively transfer and dissipate stress. This structure fundamentally changes the coating's damage mechanism, allowing stress to be dissipated within the coating through the fiber network when subjected to peeling forces. This shifts the damage mode from traditional coating-substrate interface adhesion damage to primarily cohesive or mixed damage within the coating itself. This innovative mechanism successfully unifies the contradictory characteristics of "high adhesion protection" and "non-destructive removal." By adjusting the ratio of emulsion to aerogel, the three examples achieve a gradient design of performance while maintaining the aforementioned core advantages: Example 1 demonstrates excellent overall balance; Example 2, with high matrix and low aerogel content, enhances the film's toughness and density; Example 3, with low matrix / high aerogel content, highlights superior thermal insulation and hydrophobic functions. All three achieve high adhesion, low water absorption, low thermal conductivity, and the crucial characteristic of "peeling without damaging the substrate," providing a reliable basic solution for protection needs with different focuses.

[0061] Example 4 features a targeted enhancement design on the basic system, specifically addressing the challenges of scenarios with extreme requirements for adhesion and crack resistance. Its effectiveness stems from a dual reinforcement strategy: First, at the raw material level, an adhesion-promoting silicone-modified emulsion is selected, combined with a highly reactive epoxy tackifying resin, significantly enhancing the interfacial chemical bond between the coating and the substrate, as well as its cohesive strength. Simultaneously, longer and increased quantities of basalt fibers and PVA fibers are used as a reinforcing skeleton. Second, at the process level, ultra-long-duration low-speed stirring ensures that these long fibers are fully dispersed, oriented, and interwoven into an exceptionally dense and tough three-dimensional network. This synergistic effect of "strong interface + strong skeleton" allows the coating to withstand higher stress without cracking or detaching from the substrate. Its innovation lies in the fact that even under such ultra-high strength, the carefully designed fiber network guides the effective dissipation of peel stress within the coating, achieving holistic and controllable peeling from a high-strength adhesion state, overcoming the technical bottleneck of traditional high-strength coatings being difficult to remove and prone to damaging the substrate.

[0062] Example 5 addresses the harsh environments of long-term outdoor exposure, upgrading the weather resistance of the entire system to provide a long-lasting and stable protective coating. Its significant effect is achieved through a systematic approach: the core utilizes a fluorosilicone-modified acrylic emulsion as the film-forming material, combined with a hydrophobic aerogel that has undergone secondary surface treatment with fluorosilane, constructing a low-surface-energy, highly chemically inert protective matrix. To combat UV aging, UV absorbers and light stabilizers are introduced into the additive system. Simultaneously, hydrolysis-resistant PVA fibers are selected to ensure the long-term integrity of the reinforcing network in humid and hot environments. Combined with a 96-hour curing process, the weather-resistant resin system is fully cross-linked, forming a stable and dense coating structure. Therefore, the coating obtained in this example not only inherits the peelable, waterproof, and heat-insulating properties of the base system but also exhibits excellent long-term weather resistance, resistance to acid, alkali, and salt spray corrosion, and durable flexibility, making it particularly suitable for high-end applications such as bridges, ships, and outdoor buildings requiring long-term corrosion protection, weather resistance, and maintainability.

[0063] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0064] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for preparing a waterproof aerogel coating, characterized in that, Includes the following steps: S1. Emulsion premixing and plasticizing: Under the conditions of 20-30℃ and relative humidity ≤60%, the silicone-modified acrylic emulsion and the elastic acrylate copolymer emulsion are added to the reaction vessel and stirred and mixed at a speed of 100-130 rpm for 3-5 min. S2. Pre-dispersion of additives: While maintaining stirring, add wetting and dispersing agent, film-forming aid, plasticizer, defoamer and deionized water in sequence, and then increase the stirring speed to 240-260 rpm and disperse at high speed for 12-20 min; S3. Powder premixing and gradient feeding: Dry mix the hydrophobic silica aerogel powder and the intumescent flame retardant for 5-10 minutes and pass them through an 80-120 mesh sieve. Then, under stirring, add the mixed powder to the system in step S2 in 3-5 batches. The total feeding time is 15-25 minutes. S4. High-speed shearing homogenization: Switch the agitator to perform multi-stage step shearing on the system in step S3, control the material temperature ≤38℃, until the slurry fineness ≤80 μm, and filter to obtain the base material; S5. Fiber network construction: Adjust the stirring speed to 150-190 rpm, add short-cut basalt fibers and short-cut polyvinyl alcohol fibers in sequence, stir for 18-30 min to fully disperse the fibers and form a three-dimensional network structure with the system; S6. Post-addition, degassing and curing: Add reactive tackifying resin and rheology modifier sequentially under stirring, add defoamer, adjust the total mass of the system with deionized water, then degas under vacuum of -0.085 to -0.095 MPa for 8-12 min, and finally let it stand and cure at 20-30℃ for 90 min-24 h to obtain the waterproof aerogel coating.

2. The method for preparing waterproof aerogel coating according to claim 1, characterized in that, In step S1, the amount of the silicone-modified acrylic emulsion is 23-33 parts by mass, and the amount of the elastic acrylate copolymer emulsion is 6-8 parts by mass.

3. The method for preparing waterproof aerogel coating according to claim 1, characterized in that, In step S3, the amount of the hydrophobic silica aerogel powder is 35-45 parts by mass; the intumescent flame retardant is composed of ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 10:(2-4):(2-4).

4. The method for preparing waterproof aerogel coating according to claim 1, characterized in that, In step S4, the multi-stage stepped shearing includes: a first stage of dispersion at 480-520 rpm for 4-6 min, a second stage of dispersion at 780-820 rpm for 8-12 min, and a third stage of dispersion at 1180-1220 rpm for 5-8 min.

5. The method for preparing waterproof aerogel coating according to claim 1, characterized in that, In step S5, the length of the chopped basalt fiber is 3-6 mm and the amount used is 0.3-0.8 parts by weight; the length of the chopped polyvinyl alcohol fiber is 6-10 mm and the amount used is 0.5-0.7 parts by weight.

6. The method for preparing waterproof aerogel coating according to claim 1, characterized in that, In step S6, the amount of the reactive tackifying resin is 1.8-2.5 parts by mass, and the amount of the rheology modifier is 0.5-1.0 parts by mass.

7. The method for preparing waterproof aerogel coating according to any one of claims 1-6, characterized in that, In step S1, the silicone-modified acrylic emulsion is an adhesion-promoting silicone-modified acrylic emulsion, and the elastic acrylate copolymer emulsion is a high tear-resistant elastic emulsion; in step S5, the length of the chopped basalt fiber is 6 mm and the amount is 0.8 parts by mass, the length of the chopped polyvinyl alcohol fiber is 10 mm and the amount is 0.7 parts by mass, and the stirring time for constructing the fiber network is 35-45 min.

8. The method for preparing waterproof aerogel coating according to any one of claims 1-6, characterized in that, In step S1, the film-forming base material is a fluorosilicone modified acrylic emulsion, and the amount used is 33-37 parts by weight; step S2 also includes adding 0.3-0.7 parts by weight of ultraviolet absorber and 0.2-0.4 parts by weight of light stabilizer; the hydrophobic silica aerogel powder used in step S3 is a hydrophobic silica aerogel powder that has been treated with fluorosilane twice; the short-cut polyvinyl alcohol fiber used in step S5 is a hydrolysis-resistant polyvinyl alcohol fiber.

9. The method for preparing waterproof aerogel coating according to any one of claims 1-6, characterized in that, In step S6, the reactive tackifying resin is a reactive epoxy tackifying resin or a reactive polyurethane tackifying resin.

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