A gradient hole double-enhanced aerogel energy-saving thermal insulation wall plate and a preparation method thereof

Abstract

The embodiment of the application provides a kind of gradient hole double reinforced aerogel energy-saving thermal insulation wall plate and its preparation method, including dense surface layer and double reinforced core layer sequentially arranged from outside to inside;The dense surface layer is nano-porous aerogel layer, with first pore size range;Double reinforced core layer is loose porous aerogel layer, with second pore size range greater than first pore size range, internally doped with short-cut fiber and inorganic nanoparticles as double reinforced components;The plate is prefabricated with dovetail-shaped protruding anchor structure on the side of double reinforced core layer away from dense surface layer and concave-convex slot splicing structure on side edge;Surface is provided with double-layer hydrophobic modification layer composed of inner chemical modification layer and outer nanometer oxide hydrophobic coating.The plate is synergized by gradient hole structure and double reinforced components, to improve mechanical strength and thermal insulation performance, while realizing interface stability and durability improvement, suitable for building wall energy-saving thermal insulation system.

Description

Technical Field

[0001] This application relates to the field of building energy-saving materials technology, specifically to a gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panel, its preparation method, and its mold. Background Technology

[0002] Thermal and sound insulation panels are widely used in modern buildings for insulation and soundproofing systems in structures such as walls, highways, railways, and factories. In existing technologies, aerogel is used as a functional component to prepare these panels to improve their thermal and sound insulation performance. Aerogel, due to its nanoporous structure, possesses excellent thermal insulation and acoustic barrier properties, making it suitable for applications with high requirements for energy conservation and noise control. These panels are typically made by combining aerogel with other matrix materials to achieve a certain structural strength while maintaining low thermal conductivity, and are used in exterior or interior wall systems.

[0003] In the prior art, such as Chinese patent application CN117865620A, a SiO2 aerogel inorganic thermal insulation slurry and its preparation method are disclosed. This technical solution introduces hydrophobic SiO2 aerogel powder into a cement-based slurry system in two forms: composite lightweight aggregate and water-based paste. Combined with glass fiber reinforcement and composite cementitious bonding, it prepares a thermal insulation slurry with low thermal conductivity and improved water absorption, suitable for hand application, spraying, or fabrication into boards. However, the existing slurry system uses cement as the cementitious matrix, with SiO2 aerogel dispersed as a filler component, resulting in insufficient mechanical properties and low structural strength. Although the addition of aerogel reduces the thermal conductivity, the large amount of cement matrix and vitrified microspheres in the slurry dilutes the thermal insulation advantages of the aerogel. Furthermore, the pore structure of the hardened slurry lacks a gradient design, failing to achieve synergistic optimization of dense surface protection and efficient core insulation.

[0004] However, these aerogel-based thermal and sound insulation boards still have significant shortcomings in practical applications. Due to the relatively brittle nature of aerogel, the overall strength of the resulting boards is low, making them prone to breakage or cracking under external forces. Furthermore, the weak interfacial bonding between the boards and cement-based materials results in poor adhesion stability to the wall, potentially leading to peeling during long-term use and affecting the overall structural safety and the sustainability of the insulation function. Summary of the Invention

[0005] This application provides a gradient-pore double-reinforced aerogel energy-saving insulation wall panel, its preparation method, and a mold, aiming to improve the problems of existing aerogel insulation panels being brittle, easily absorbing water, having poor adhesion to walls, and having low construction adaptability.

[0006] A gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panel, comprising a dense surface layer and a double-reinforced core layer arranged sequentially from the outside to the inside; The dense surface layer is a nanoporous aerogel layer with a first pore size range; The dual-reinforced core layer is a loose porous aerogel layer with a second pore size range larger than the first pore size range; the dual-reinforced core layer is doped with short-cut fibers and inorganic nanoparticles as dual reinforcement components. The panels are prefabricated with an anchoring structure on the side of the double-reinforced core layer away from the dense surface layer and a splicing structure on the side. The surface of the board is covered with a double-layer hydrophobic modified layer.

[0007] The above scheme achieves synergistic optimization of surface weather resistance and core insulation. The dense surface layer's microporous structure (5–20 nm) significantly enhances surface hardness and wear resistance, effectively preventing moisture intrusion, while the dual-reinforced core layer's macroporous structure (20–50 nm) maintains high porosity, ensuring a thermal conductivity ≤0.020 W / (m·K). This solves the technical bottleneck of traditional uniform-pore aerogels struggling to balance weather resistance and insulation. Simultaneously, the introduction of chopped fibers and inorganic nanoparticles synergistically improves mechanical properties. The integrated design of the anchoring and splicing structures enhances mechanical bonding with the wall substrate, avoiding reliance on anchor bolts and eliminating thermal bridging effects. The double-layer hydrophobic modified layer further ensures long-term environmental stability.

[0008] The thickness of the dense surface layer is 0.5–1.5 mm, and the thickness of the double-reinforced core layer is 20–50 mm.

[0009] The above solution achieves an optimal balance between structural strength and thermal insulation, as the dense surface layer within this thickness range is sufficient to form a continuous and dense barrier, preventing external moisture penetration and mechanical damage, while not affecting the overall flexibility of the board. The thickness of the double-reinforced core layer is controlled between 20 and 50 mm, which can meet the thermal resistance requirements of building energy-saving design while ensuring the structural stability and load-bearing capacity of the material.

[0010] The chopped fibers are chopped basalt fibers with a length of 1–3 mm, and the dosage is 5%–8% of the mass of the aerogel matrix; the inorganic nanoparticles are nano-titanium dioxide particles with a particle size of 20–50 nm, and the dosage is 2%–3% of the mass of the aerogel matrix.

[0011] The above-mentioned method can significantly improve the flexural strength and impact resistance of the board. This is because the short-cut basalt fibers, at this length and dosage, can be uniformly dispersed in the aerogel matrix, forming a three-dimensional network structure that effectively transfers stress and inhibits crack propagation, resulting in a flexural strength ≥1.6 MPa and an impact strength increase of over 40%. Furthermore, the nano-titanium dioxide particles not only act as rigid fillers to reinforce the skeletal structure but also possess UV shielding properties, improving the material's aging resistance. The anchoring structure is a dovetail-shaped protrusion integrally formed with the double-reinforced core layer; the splicing structure is a groove structure with concave and convex edges set on the side of the board for mechanical fastening between adjacent boards.

[0012] The above solution can significantly improve construction efficiency and interface connection reliability. The dovetail protrusion can be embedded in the pre-reserved groove in the wall base to form a mechanical interlock, which can achieve firm fixation without the need for additional anchor bolts and eliminate the thermal bridging problem caused by metal anchor bolts. The side concave and convex grooves allow adjacent panels to be quickly aligned and spliced, reducing on-site cutting and adjustment time and shortening the construction period by more than 30%.

[0013] The dual-layer hydrophobic modification layer includes an inner chemical modification layer and an outer coating modification layer; The inner chemically modified layer is formed by hydrophobizing the surface of the aerogel with an organosilane coupling agent; The outer coating modification layer is a nano-oxide hydrophobic coating.

[0014] The above solution achieves long-lasting waterproofing and weather resistance. The inner layer uses organosilanes such as methyltrimethoxysilane to chemically graft hydroxyl groups onto the aerogel surface, reducing surface energy and imparting hydrophobicity. The outer layer is sprayed with nano-silica sol to form a physical barrier with a micro-nano rough structure, further enhancing the hydrophobic effect and resisting acid and alkali immersion and UV aging. The water contact angle is measured using a contact angle meter, and the coating integrity is observed using SEM. The double-layer structure maintains a thermal conductivity change rate of ≤5% even under long-term outdoor exposure, effectively preventing insulation failure due to water absorption.

[0015] A method for preparing gradient-pore dual-reinforced aerogel energy-saving and heat-insulating wall panels includes: providing silicon source, solvent, catalyst, chopped fibers and inorganic nanoparticles as raw materials; High-concentration dense surface sol and low-concentration dual-reinforced core sol were prepared separately. The dense surface sol is injected into a mold with anchoring and splicing structures, and left to stand to form the initial surface layer. After the initial surface layer is pre-cured, a double-reinforced core layer sol containing chopped fibers and inorganic nanoparticles is injected and reinforced mesh fabric is embedded. After sealing, a gelation reaction is carried out to obtain a gradient pore wet gel board. The wet gel plate was subjected to aging treatment and solvent replacement treatment in sequence; The wet aerogel plates after displacement were dried using a segmented atmospheric pressure drying process to obtain aerogel preforms; The preform undergoes a double-layer hydrophobic modification process: first, an inner layer of chemical hydrophobic modification is performed, and then an outer layer of nano-hydrophobic coating is applied and cured to obtain the finished board.

[0016] The above-described solution enables the integrated manufacturing of gradient structures and multiple functions. The stepwise sol preparation and sequential casting technology ensures the orderly superposition of the dense surface layer and the loose core layer, preventing mixing and resulting in structural homogenization. Pre-set dovetail grooves and slots in the mold allow anchoring and splicing components to be formed during the gelation stage, ensuring structural consistency. Embedded fiberglass mesh further enhances overall tensile strength. The entire process is compatible with industrial production, requires no supercritical drying equipment, and can obtain crack-free blanks through atmospheric pressure drying. It boasts low production costs, good repeatability, and is suitable for large-scale building panel manufacturing.

[0017] The solid content of the high-concentration dense surface sol is higher than that of the double-reinforced core sol; The catalyst includes an acidic catalyst and a basic catalyst, and the hydrolysis reaction and polycondensation reaction of the silicon source are controlled separately by adjusting the pH value in stages.

[0018] The acidic catalyst is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, citric acid, oxalic acid, formic acid, boric acid, p-toluenesulfonic acid, and aminosulfonic acid; preferably one or more of hydrochloric acid, acetic acid, citric acid, or oxalic acid; more preferably hydrochloric acid or acetic acid. The role of the acidic catalyst is to promote the hydrolysis reaction of the silicon source, causing the silicon-oxygen bonds in the silicon source molecules to break, generating silanol (Si-OH) precursors. Under acidic conditions, the hydrolysis rate is faster while the condensation rate is slower, which is beneficial for obtaining a uniform sol system and lays the foundation for the subsequent formation of a dense nanoporous structure.

[0019] The alkaline catalyst is selected from one or more of ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, ethylenediamine, and triethylamine; preferably one or more of ammonia, sodium hydroxide, or ammonium carbonate; more preferably ammonia or sodium hydroxide. The alkaline catalyst accelerates the polycondensation reaction of the silanol precursor, promoting dehydration condensation between Si-OH groups to form a stable Si-O-Si three-dimensional network framework. Under alkaline conditions, the polycondensation reaction rate is significantly accelerated, which is beneficial for forming a gel network in a shorter time, while controlling the pore growth rate to obtain a loose and porous core structure. Ammonia, as a volatile alkali, is easily volatilized during the drying process, reducing the impact of residual ions on the aerogel properties; sodium hydroxide and potassium hydroxide are strongly alkaline, which can significantly shorten the gelation time, making them suitable for large-scale industrial production; organic bases such as ethylenediamine and triethylamine provide a relatively mild polycondensation environment, preventing the gel from cracking too quickly.

[0020] During the preparation process, the pH is first adjusted to an acidic range to promote hydrolysis, and then adjusted to an alkaline range to promote polycondensation.

[0021] The above scheme allows for precise control of the sol-gel process to match the requirements of the gradient structure. High-solids-content sols (25%–30%) promote the formation of a dense network and a porous surface layer, while low-solids-content sols (15%–20%) facilitate the formation of a loose, porous core layer, preserving excellent thermal insulation properties. Acidic conditions (pH=2–3) promote the complete hydrolysis of the silicon source to generate silanols, while alkaline conditions (pH=8–9) accelerate the condensation reaction to form a Si-O-Si network. This two-step pH control strategy effectively controls the gelation rate, preventing defects caused by excessively rapid gelation.

[0022] The segmented atmospheric pressure drying process consists of two stages: the first stage involves drying at 60–80°C for 6–8 hours, and the second stage involves heating to 100–120°C for 12–16 hours; the heating rate is 5–10°C / h.

[0023] The above method avoids cracking and deformation caused by sudden changes in capillary pressure during drying. Slow heating (5~10℃ / h) allows the solvent to evaporate gradually, releasing internal stress evenly. The low-temperature stage removes most of the ethanol and water, while the high-temperature stage completely eliminates residual solvent and enhances network cross-linking. This process replaces expensive supercritical drying, has low equipment costs, and is suitable for mass production. Drying temperature and time are set by the oven temperature control system, and the heating rate is verified through program control. In the examples, heating to 70℃ and 110℃ at 8℃ / h both yielded complete, crack-free green bodies with high product consistency.

[0024] When using water glass as a silicon source, it is first acidified to a pH of 3-4, and then filtered to remove impurities before being used for sol preparation.

[0025] The above approach expands raw material sources and ensures sol quality. While water glass is significantly cheaper than tetraethyl orthosilicate, it contains more metal ions and colloidal impurities, which can lead to uneven gelation or defects if used directly. Acidification to pH 3-4 allows for appropriate silicic acid polymerization and promotes impurity precipitation. After filtration, a pure silicic acid solution is obtained, which can be used for subsequent sol preparation. pH is controlled using acid-base titration with a pH meter, and filtration is performed using a microporous membrane (e.g., 0.45 μm). This pretreatment process ensures that high-performance aerogel sheets can be produced from low-cost raw materials, facilitating large-scale application.

[0026] A mold for a gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panel includes: For forming the aforementioned sheet metal, the bottom mold of the mold is provided with a female mold structure corresponding to the anchoring structure, and the side mold is provided with a male mold or female mold structure corresponding to the splicing structure. It enables the simultaneous prefabrication of anchoring and splicing structures during the sheet forming process.

[0027] The above solution enables the one-time molding of complex structures. Because the bottom mold features a dovetail groove structure, a matching dovetail-shaped protrusion anchoring structure can be directly formed during gelation. The side mold is equipped with complementary concave and convex modules, simultaneously constructing splicing slots without the need for post-processing. The mold structure ensures precise positioning and consistent dimensions of all functional components, improving mass production efficiency and product standardization.

[0028] The female mold structure is a dovetail groove structure that matches the dovetail protrusion; The male or female mold structure on the side mold is constructed into complementary shapes that can form concave and convex grooves.

[0029] The above solution ensures the geometric compatibility and mechanical reliability of the anchoring and splicing structures. The dovetail groove structure has self-locking properties, resulting in low demolding resistance while maintaining strong pull-out resistance during use, thus guaranteeing the stability of the anchoring structure after embedding it into the wall. The complementary concave-convex structure of the side mold ensures precise interlocking of adjacent plates, resulting in tight joints and reducing thermal bridging and air leakage. The mold structure is made of wear-resistant materials (such as stainless steel), has a long service life, and can be reused hundreds of times, significantly reducing unit production costs and supporting efficient continuous production. Attached Figure Description

[0030] Figure 1 Schematic diagram of the structure of energy-saving and heat-insulating wall panels; Figure 2 Physical image of the dual-reinforced core layer; Figure 3 Microstructure diagram of short-cut basalt fibers in the double-reinforced core layer; Figure 4 Microstructure diagram of the dual-reinforced core layer components. Detailed Implementation

[0031] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0032] Example 1: like Figure 1 As shown in the embodiment of this application, a gradient-pore dual-reinforced aerogel energy-saving and heat-insulating wall panel is provided, comprising a dense surface layer 1 and a dual-reinforced core layer 2 arranged sequentially from the outside to the inside; the dense surface layer 1 is a nanoporous aerogel layer with a first pore size range; the dual-reinforced core layer 2 is a loose porous aerogel layer with a second pore size range larger than the first pore size range; the dual-reinforced core layer 2 is doped with short-cut fibers and inorganic nanoparticles as dual reinforcement components; the panel 3 is prefabricated with an anchoring structure located on the side of the dual-reinforced core layer away from the dense surface layer and a splicing structure located on the side; the surface of the panel is provided with a double-layer hydrophobic modification layer.

[0033] Compared to existing technologies that use GRC layers to encapsulate aerogel or composite multilayer structures with adhesives, this application avoids the problem of weak interfacial adhesion by using an integrated gradient pore structure and built-in reinforcement system, which significantly improves the overall mechanical stability and durability. At the same time, compared to technologies that rely on supercritical drying to prepare rigid aerogel boards, this application uses an atmospheric pressure drying process, which greatly reduces equipment costs and production energy consumption, making it more suitable for large-scale building applications.

[0034] The dense surface layer 1 has a pore size range of 5~20nm and is formed by gelation of high solid content sol. It has a high network density, which can effectively improve surface hardness and wear resistance, and block water penetration. The double-reinforced core layer 2 has a pore size range of 20~50nm and is formed by gelation after introducing short-cut fibers and inorganic nanoparticles into a low solid content sol. It maintains high porosity to achieve excellent thermal insulation performance, with a thermal conductivity ≤0.020W / (m·K).

[0035] Short-cut fibers are uniformly dispersed in the double-reinforced core layer 2, and work synergistically with inorganic nanoparticles on the aerogel skeleton to improve the flexural strength and impact resistance of the material. The length of the short-cut fibers is adapted to the matrix structure, which can bridge microcracks under stress and inhibit their propagation. Inorganic nanoparticles fill the gaps in the gel network, enhance the rigidity of the skeleton and improve the anti-aging properties.

[0036] The anchoring structure is a mechanically interlocking structure integrally formed at the bottom of the double-reinforced core layer. It can be embedded into the pre-reserved groove in the wall base during installation to achieve anchor-free fixing and eliminate the thermal bridging effect. The splicing structure is set on the side of the board and is constructed in the form of concave and convex grooves, which allows adjacent boards to be quickly aligned and spliced, reducing construction adjustment time and improving assembly efficiency.

[0037] A double-layer hydrophobic modified layer covers the entire surface of the board. The inner layer is a hydrophobic layer formed by chemical grafting with an organosilane coupling agent, which reduces the surface energy of the aerogel and gives it hydrophobicity. The outer layer is a nano-oxide hydrophobic coating formed by spraying, which constructs a micro-nano rough structure to enhance the physical barrier function and effectively prevent the thermal conductivity from deteriorating due to water absorption.

[0038] Example 2: like Figure 2 As shown, the gradient pore double-reinforced aerogel energy-saving and heat-insulating wall panel provided in this application embodiment also includes a dense surface layer with a thickness of 0.5 to 1.5 mm and a double-reinforced core layer with a thickness of 20 to 50 mm.

[0039] The thickness design achieves an optimal balance between structural strength and thermal insulation: the dense surface layer can form a continuous and dense barrier within this range, which is sufficient to resist external mechanical damage and moisture intrusion, without affecting the overall flexibility; the thickness of the double-reinforced core layer meets the thermal resistance requirements of building energy-saving design, and maintains structural stability and load-bearing capacity while ensuring good thermal insulation performance, which meets the actual needs of conventional wall engineering for insulation layer thickness.

[0040] Example 3: like Figure 3-4 As shown, the gradient pore double-reinforced aerogel energy-saving and heat-insulating wall panel provided in this application embodiment also includes chopped basalt fibers with a length of 1 to 3 mm and a doping amount of 5% to 8% of the aerogel matrix mass; and inorganic nanoparticles with nano titanium dioxide particles with a particle size of 20 to 50 nm and a doping amount of 2% to 3% of the aerogel matrix mass.

[0041] Short-cut basalt fibers, at this length and dosage, can be fully dispersed in the aerogel matrix to form a three-dimensional network structure, effectively transferring stress and inhibiting crack propagation, resulting in a flexural strength of ≥1.6MPa and an impact strength increase of over 40%. Nano-titanium dioxide particles not only serve as rigid fillers to strengthen the skeleton structure but also possess UV shielding capabilities, significantly improving the material's aging resistance in outdoor environments and extending its service life.

[0042] Example 4: The gradient hole double-reinforced aerogel energy-saving and heat-insulating wall panel provided in this application embodiment also includes an anchoring structure that is a dovetail-shaped protrusion integrally formed with the double-reinforced core layer; and a splicing structure that is a concave-convex groove structure set on the side of the panel for mechanical fastening between adjacent panels.

[0043] The dovetail-shaped protrusions can be embedded into the matching grooves reserved in the wall base to form a self-locking mechanical interlock, which can achieve firm fixation without the need for additional metal anchors, fundamentally eliminating the problem of thermal bridging; the side concave and convex grooves allow adjacent panels to be spliced ​​and positioned quickly and accurately, reducing on-site cutting and bonding processes, shortening the construction period by more than 30%, and improving construction efficiency and joint sealing.

[0044] Example 5: The gradient pore double-reinforced aerogel energy-saving and heat-insulating wall panel provided in this application embodiment also includes a double-layer hydrophobic modification layer, including an inner chemical modification layer and an outer coating modification layer; the inner chemical modification layer is formed by hydrophobizing the aerogel surface with an organosilane coupling agent; the outer coating modification layer is a nano-oxide hydrophobic coating.

[0045] The inner layer uses organosilanes such as methyltrimethoxysilane to chemically graft hydroxyl groups on the surface of the aerogel, reducing the surface free energy and giving the material bulk-level hydrophobicity; the outer layer is sprayed with nano-silica sol and cured to form a physical protective layer with a micro-nano rough structure, which further enhances the hydrophobic effect. The dual mechanism works together to ensure long-term waterproof and weather-resistant performance, so that the board can still maintain a thermal conductivity change rate of ≤5% under harsh environments such as acid and alkali corrosion and ultraviolet radiation, preventing failure due to water absorption.

[0046] Example 6: This application also provides a method for preparing gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panels.

[0047] Silicon source, solvent, catalyst, short-cut fiber and inorganic nanoparticles are used as raw materials.

[0048] High-concentration dense surface sol and low-concentration dual-reinforced core sol were prepared separately.

[0049] The dense surface sol is injected into a mold with anchoring and splicing structures, and left to stand to form the initial surface layer.

[0050] After the initial surface layer is pre-cured, a double-reinforced core layer sol containing chopped fibers and inorganic nanoparticles is injected, and a reinforcing mesh is embedded. After sealing, a gelation reaction is carried out to obtain a gradient pore wet gel board.

[0051] The wet gel plates were subjected to aging treatment and solvent replacement treatment in sequence.

[0052] A segmented atmospheric pressure drying process was used to dry the replaced wet gel plate to obtain an aerogel preform.

[0053] The preform undergoes a double-layer hydrophobic modification process: first, an inner layer of chemical hydrophobic modification is performed, and then an outer layer of nano-hydrophobic coating is applied and cured to obtain the finished board.

[0054] Example 7: The preparation method provided in this application also includes a high-concentration dense surface sol with a solid content higher than that of the double-reinforced core sol; during the preparation process, the pH is first adjusted to an acidic range to promote hydrolysis, and then the pH is adjusted to an alkaline range to promote polycondensation reaction.

[0055] High-solids-content sols (25%–30%) promote the formation of a dense network structure, generating a dense surface layer with small pores and improving surface properties; low-solids-content sols (15%–20%) promote the formation of a loose and porous core layer, retaining high porosity to ensure low thermal conductivity. Acidic conditions (pH=2–3) promote the complete hydrolysis of silicon sources to generate silanols, while alkaline conditions (pH=8–9) accelerate the condensation reaction to form a stable Si-O-Si network structure. This two-step pH control strategy precisely controls the gelation rate, preventing excessively rapid gelation that could lead to defects and ensuring the integrity of the gradient structure.

[0056] In this embodiment, a two-step acid-base catalysis method is adopted: first, under the action of an acidic catalyst, the system is stirred and hydrolyzed at pH 2-3 for 0.5-2 hours to ensure that the silicon source is fully hydrolyzed to generate silanol precursors; then, an alkaline catalyst is added to adjust the pH of the system to 8-9, and the system is stirred for 5-30 minutes before being allowed to stand and gel.

[0057] By first promoting hydrolysis and then accelerating condensation in stages, gel defects caused by insufficient hydrolysis or stress concentration caused by excessively rapid condensation are effectively avoided, ensuring the formation of an orderly gradient structure between the dense surface layer and the loose core layer.

[0058] The amount of catalyst added is calculated based on the molar amount of the silicon source. For acidic catalysts, the amount added is the equivalent required to achieve a pH of 2–3 in the sol system, typically 0.1%–5% of the molar amount of the silicon source; for basic catalysts, the amount added is the equivalent required to achieve a pH of 8–9 in the sol system, typically 0.5%–10% of the molar amount of the silicon source. The specific amount of catalyst can be fine-tuned according to factors such as the type of silicon source, sol concentration, and ambient temperature to optimize gelation time and product quality.

[0059] In another embodiment of this application, when water glass is used as the silicon source, the acidic catalyst is preferably hydrochloric acid or sulfuric acid, which adjusts the pH to 3-4 during the acidification treatment stage and also precipitates impurity ions (such as Fe3+, Al3+, etc.); the alkaline catalyst is preferably ammonia or ammonium carbonate, which provides a mild alkaline environment during the polycondensation stage and avoids the introduction of a large number of metal ions by strong alkali (such as NaOH) which would affect the hydrophobic properties of the aerogel.

[0060] Using the aforementioned acid-base segmented catalytic system, the gradient-pore aerogel board of this application can obtain a uniform and continuous pore structure under normal pressure drying conditions. The pore size of the dense surface layer is controlled at 5–20 nm, and the pore size of the double-reinforced core layer is controlled at 20–50 nm, while ensuring the mechanical strength of the skeleton, achieving a flexural strength ≥1.6 MPa and a thermal conductivity ≤0.020 W / (m·K). The selection and optimization of catalyst dosage are among the key steps in achieving the industrial production of low-cost, high-performance aerogel insulation boards.

[0061] Example 8: The preparation method provided in this application embodiment also includes segmented atmospheric pressure drying, which includes two stages: the first stage is drying at 60-80°C for 6-8 hours, and the second stage is drying at 100-120°C for 12-16 hours; the heating rate is 5-10°C / h.

[0062] Slow temperature control allows the solvent to evaporate gradually, avoiding cracking and deformation caused by sudden changes in capillary pressure. The low-temperature stage mainly removes most of the ethanol and water, while the high-temperature stage completely removes residual solvent and enhances the network crosslinking density. The atmospheric pressure drying process replaces the expensive supercritical drying, has lower equipment requirements, is suitable for industrial mass production, and ensures the integrity of the green body and high product consistency through gradient sol ratio and drying parameter optimization.

[0063] Example 9: The preparation method provided in this application also includes, when using water glass as a silicon source, first acidifying it to a pH of 3-4, filtering out impurities, and then using it for sol preparation.

[0064] Water glass is far less expensive than tetraethyl orthosilicate, but it contains more metal ions and colloidal impurities, which can easily lead to uneven gelation or defects when used directly. Acidification to pH 3-4 promotes moderate polymerization of silicic acid and precipitates impurities. After filtration, a pure silicic acid solution is obtained, which can be used for subsequent sol preparation. This pretreatment step expands the source of raw materials, ensuring that high-performance aerogel sheets can still be produced at low cost, which is conducive to large-scale application.

[0065] In this application, "multiple" refers to two or more.

[0066] In this application, unless otherwise expressly defined, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0067] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panel, characterized in that... , include: A dense surface layer and a double-reinforced core layer are arranged sequentially from the outside to the inside; The dense surface layer is a nanoporous aerogel layer with a first pore size range; The dual-reinforced core layer is a loose porous aerogel layer with a second pore size range that is larger than the first pore size range; The dual-reinforced core layer is doped with short-cut fibers and inorganic nanoparticles as dual reinforcement components. The board is prefabricated with an anchoring structure located on the side of the double-reinforced core layer away from the dense surface layer and a splicing structure located on the side. The surface of the plate is provided with a double-layer hydrophobic modification layer.

2. The gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panel according to claim 1, characterized in that, The thickness of the dense surface layer is 0.5–1.5 mm, and the thickness of the double-reinforced core layer is 20–50 mm.

3. The gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panel according to claim 1, characterized in that, The chopped fibers are chopped basalt fibers with a length of 1–3 mm, and the dosage is 5%–8% of the mass of the aerogel matrix; The inorganic nanoparticles are nano-titanium dioxide particles with a particle size of 20-50 nm, and the doping amount is 2%-3% of the mass of the aerogel matrix.

4. The gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panel according to claim 1, characterized in that, The anchoring structure is a dovetail-shaped protrusion integrally formed with the double-reinforced core layer; The splicing structure is a groove structure with concave and convex grooves set on the side of the board, which is used for mechanical fastening between adjacent boards.

5. The gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panel according to claim 1, characterized in that, The bilayer hydrophobic modified layer includes an inner chemical modified layer and an outer coating modified layer; The inner chemically modified layer is formed by hydrophobicating the aerogel surface with an organosilane coupling agent. The outer coating modification layer is a nano-oxide hydrophobic coating.

6. A method for preparing gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panels, characterized in that... , include: Silicon sources, solvents, catalysts, chopped fibers, and inorganic nanoparticles are provided as raw materials; High-concentration dense surface sol and low-concentration dual-reinforced core sol were prepared separately. The dense surface sol is injected into a mold with anchoring and splicing structures, and left to stand to form the initial surface layer. After the initial surface layer is pre-cured, a double-reinforced core layer sol containing chopped fibers and inorganic nanoparticles is injected and reinforced mesh fabric is embedded. After sealing, a gelation reaction is carried out to obtain a gradient pore wet gel board. The wet gel plate was subjected to aging treatment and solvent replacement treatment in sequence; The wet aerogel plates after displacement were dried using a segmented atmospheric pressure drying process to obtain aerogel preforms; The preform undergoes a double-layer hydrophobic modification process: first, an inner layer of chemical hydrophobic modification is performed, and then an outer layer of nano-hydrophobic coating is applied and cured to obtain the finished board.

7. The method for preparing gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panels according to claim 6, characterized in that, The solid content of the high-concentration dense surface sol is higher than that of the double-reinforced core sol. In the preparation process, the pH is first adjusted to an acidic range using a catalyst to promote hydrolysis, and then adjusted to an alkaline range to promote polycondensation. The catalyst includes an acidic catalyst and an alkaline catalyst. The acidic catalyst is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, citric acid, oxalic acid, formic acid, boric acid, p-toluenesulfonic acid, and aminosulfonic acid. The alkaline catalyst is selected from one or more of ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, ethylenediamine, and triethylamine.

8. The method for preparing gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panels according to claim 6, characterized in that, The segmented atmospheric pressure drying includes two stages: the first stage is drying at 60-80℃ for 6-8 hours, and the second stage is drying at 100-120℃ for 12-16 hours; the heating rate is 5-10℃ / h.

9. The method for preparing gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panels according to claim 6, characterized in that, When using water glass as a silicon source, it is first acidified to a pH of 3-4, and then filtered to remove impurities before being used for sol preparation.

10. A mold for a gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panel, characterized in that... , include: For forming the sheet metal as described in claim 1, the bottom mold of the mold is provided with a female mold structure corresponding to the anchoring structure, and the side mold is provided with a male mold or female mold structure corresponding to the splicing structure. It enables the simultaneous prefabrication of anchoring and splicing structures during the sheet forming process.

11. The mold for the gradient-pore double-reinforced aerogel energy-saving and heat-insulating wall panel according to claim 10, characterized in that, The female mold structure is a dovetail groove structure that matches the dovetail protrusion; the male or female mold structure on the side mold is constructed into a complementary shape that can form concave and convex grooves.

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