Aerogel composite thermal insulation material and preparation method and application thereof

Abstract

The present application relates to aerogel thermal insulation material technical field, particularly relates to a kind of aerogel composite thermal insulation material and its preparation method and application.Aerogel composite thermal insulation material adopts the matrix phase formed by polyvinyl alcohol and water, composite filler consisting of silica aerogel and hollow floating bead and / or expanded perlite, and composite additive consisting of dispersing agent, wetting agent and coupling agent, and is compounded according to specific proportion.The composite thermal insulation material is stable in the premise of controlling the thermal conductivity coefficient at 0.04W·m ‑1 ·K ‑1 Within, significantly reduce the aerogel dosage, material total cost is reduced by 30%-40%, while the compressive strength is increased to 0.70-1.08 MPa, water contact angle reaches 108-126 °, and has excellent flame retardant and weather resistance, applicable to building, industrial pipeline, cold chain and other fields.

Description

Technical Field

[0001] This invention relates to the field of aerogel insulation materials technology, and in particular to an aerogel composite insulation material, its preparation method, and its application. Background Technology

[0002] Silica aerogel materials are considered ideal lightweight insulation materials due to their extremely high porosity and extremely low thermal conductivity. However, traditional silica aerogel insulation materials face several prominent technical bottlenecks in practical applications.

[0003] Firstly, to achieve ideal thermal insulation performance, existing materials often require a high amount of silica aerogel, leading to high raw material costs and limiting their economic viability in large-scale engineering projects such as construction and industrial pipelines. How to significantly reduce the amount of silica aerogel used and control the total material cost while maintaining low thermal conductivity is a pressing issue for the industry.

[0004] Secondly, silica aerogels themselves have poor mechanical properties, especially low compressive strength, making it difficult to withstand compressive loads in actual working conditions when used alone. Existing technologies attempt to improve mechanical properties by adding inorganic fillers or reinforcing fibers, but this often comes at the cost of sacrificing thermal insulation performance, making it difficult to effectively improve compressive strength while maintaining low thermal conductivity.

[0005] Furthermore, significant interfacial compatibility issues exist between silica aerogels and commonly used inorganic fillers or other matrices. Due to surface energy differences, inorganic fillers are prone to agglomeration in the matrix, leading to uneven dispersion. Simultaneously, the inorganic fillers lack strong chemical bonds with the organic matrix, resulting in low interfacial bonding strength. Under external forces or environmental changes, interfacial debonding easily occurs, leading to the propagation of microcracks within the material, degradation of mechanical properties, and the formation of water vapor permeation channels. This not only reduces the long-term stability of the material but also causes a gradual deterioration in its thermal insulation performance.

[0006] Furthermore, unmodified silica aerogel composite insulation materials readily adsorb moisture from the environment, either directly or at their interfaces. Water molecules entering the porous structure significantly increase thermal conductivity, impairing insulation performance and potentially accelerating material aging. Therefore, while maintaining low thermal conductivity, providing materials with durable hydrophobic properties through simple and efficient methods is crucial for broadening their application range and improving weather resistance.

[0007] Therefore, it is of great significance to develop a composite thermal insulation material that can significantly reduce the amount of silica aerogel used while possessing low thermal conductivity, high compressive strength, excellent interfacial bonding strength, good hydrophobic properties, and long-term weather resistance. Summary of the Invention

[0008] The purpose of this invention is to overcome the problem that existing aerogel composite insulation materials cannot simultaneously achieve low cost, low thermal conductivity, high mechanical strength, good interfacial compatibility and bonding strength of composite materials, as well as good hydrophobicity and long-term weather resistance. This invention provides an aerogel composite insulation material, its preparation method, and its applications. This aerogel composite insulation material is formulated using a matrix phase formed from polyvinyl alcohol and water, a composite filler composed of silica aerogel, hollow cenospheres, and / or expanded perlite, and a composite additive composed of dispersants, wetting agents, and coupling agents, blended in a specific ratio. The thermal conductivity is stably controlled at 0.04 W·m. -1 ·K -1 Under the premise of within, the amount of aerogel used is significantly reduced, the total material cost is reduced by 30%-40%, while the compressive strength is increased to 0.70-1.08 MPa, with good interfacial compatibility and bonding strength, a water contact angle of 108-126°, and excellent flame retardant and weather resistance properties.

[0009] A first aspect of the present invention provides an aerogel composite thermal insulation material, which is prepared from raw materials comprising the following parts by weight:

[0010] Polyvinyl alcohol: 5-10 parts; Water: 80-120 parts; 60-150 parts of silica aerogel; 50-120 parts of inorganic particles; Dispersant 0.6–3.5 parts; Wetting agent 0.15–3 parts; 0.5 to 2 parts of coupling agent; The inorganic particles are selected from at least one of hollow cenospheres and expanded perlite.

[0011] This invention provides an aerogel composite thermal insulation material, which comprises a matrix phase formed by polyvinyl alcohol and water, a composite filler consisting of 60-150 parts by weight of silica aerogel and 50-120 parts by weight of hollow cenospheres and / or expanded perlite, and a composite additive consisting of 0.6-3.5 parts by weight of dispersant, 0.15-3 parts by weight of wetting agent, and 0.5-2 parts by weight of coupling agent, compounded in a specific ratio. In this material, the nanoporous structure of silica aerogel and the micron-scale hollow structure of hollow cenospheres / expanded perlite interpenetrate each other, forming a dual low thermal conductivity network at nano-micron multi-scale, effectively extending the heat conduction path and suppressing gas convection heat transfer. Simultaneously, the dispersant in the composite additive prevents filler particle agglomeration through steric hindrance, the wetting agent reduces the surface tension of the polyvinyl alcohol aqueous solution to improve wettability to hydrophobic aerogels and inorganic particles, and the coupling agent forms a chemical bond between the filler surface and the polyvinyl alcohol matrix, constructing a strong interfacial bonding layer. The composite insulation material has a stable thermal conductivity of 0.04 W·m.-1 ·K -1 Under the premise of keeping costs within a certain range, the amount of aerogel used is significantly reduced, the total material cost is reduced by 30%-40%, while the compressive strength is increased to 0.70-1.08 MPa, the water contact angle reaches 108-126°, and the interfacial bonding strength and long-term weather resistance are all superior to existing technologies, thus achieving a combination of low cost and high performance.

[0012] Furthermore, the weight ratio of silica aerogel to inorganic particles is 1:1 to 1.5:1.

[0013] Furthermore, the weight ratio of the dispersant, wetting agent and coupling agent is (3-5):1:(1-3.5).

[0014] Furthermore, the dispersant is sodium polycarboxylate, the wetting agent is AEO-9, and the coupling agent is KH-560. Preferably, the sodium polycarboxylate has a molecular weight of 10,000-15,000.

[0015] A second aspect of the present invention provides a method for preparing an aerogel composite thermal insulation material as described above, comprising the following steps: Polyvinyl alcohol is added to water, heated and stirred to dissolve, resulting in a polyvinyl alcohol solution; Add wetting agent, dispersant and coupling agent to polyvinyl alcohol solution, stir and mix to obtain modified polyvinyl alcohol matrix solution; A composite filler is obtained by mixing silica aerogel with inorganic particles; The composite filler is added to the modified polyvinyl alcohol matrix solution in at least two batches and stirred to obtain the composite slurry. The composite slurry is poured into a mold and pressed at room temperature to obtain the initial blank. The initial preform is dried to obtain an aerogel composite insulation material.

[0016] Furthermore, during the preparation of the polyvinyl alcohol solution, the temperature is raised to 90℃-95℃ and stirred to dissolve for 3-4 hours.

[0017] Furthermore, during the preparation of the composite slurry, the modified polyvinyl alcohol matrix solution is added in two stages: the first stage adds 40% to 60% of the total weight of the composite filler and stirs for 5 to 10 minutes; the second stage adds the remaining composite filler and stirs for 10 to 15 minutes.

[0018] Furthermore, during the initial blank preparation process, the pressing pressure is 3–5 MPa, and the holding time is 5–10 min.

[0019] Furthermore, the initial blank is dried by forced air drying at a temperature of 60℃-70℃ for 18-24 hours.

[0020] The aerogel composite insulation material described above, or the aerogel composite insulation material prepared according to the method described above, has a thermal conductivity of 0.033–0.039 W·m. -1 ·K -1 The compressive strength is 0.70–1.08 MPa, and the water contact angle is 108–126°.

[0021] The third aspect of this invention provides the application of the above-described aerogel composite insulation material or the aerogel composite insulation material prepared by the above-described method in the fields of building insulation, cold chain logistics or pipeline insulation.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides an aerogel composite thermal insulation material, which comprises a matrix phase formed by polyvinyl alcohol and water, a composite filler consisting of 60-150 parts by weight of silica aerogel and 50-120 parts by weight of hollow cenospheres and / or expanded perlite, and a composite additive consisting of 0.6-3.5 parts by weight of dispersant, 0.15-3 parts by weight of wetting agent, and 0.5-2 parts by weight of coupling agent, compounded in a specific ratio. In this material, the nanoporous structure of silica aerogel and the micron-scale hollow structure of hollow cenospheres / expanded perlite interpenetrate each other, forming a dual low thermal conductivity network at nano-micron multi-scale, effectively extending the heat conduction path and suppressing gas convection heat transfer. Simultaneously, the dispersant in the composite additive prevents filler particle agglomeration through steric hindrance, the wetting agent reduces the surface tension of the polyvinyl alcohol aqueous solution to improve wettability to hydrophobic aerogels and inorganic particles, and the coupling agent forms a chemical bond between the filler surface and the polyvinyl alcohol matrix, constructing a strong interfacial bonding layer. The composite insulation material has a stable thermal conductivity of 0.04 W·m. -1 ·K -1 Under the premise of keeping costs within a certain range, the amount of aerogel used is significantly reduced, the total material cost is reduced by 30%-40%, while the compressive strength is increased to 0.70-1.08 MPa, the water contact angle reaches 108-126°, and the interfacial bonding strength and long-term weather resistance are all superior to existing technologies, thus achieving a combination of low cost and high performance.

[0023] 2. The aerogel composite insulation material preparation method provided by the present invention first pre-modifies the matrix by adding wetting agent, dispersant and coupling agent to polyvinyl alcohol solution, and then adding silica aerogel and inorganic particle composite filler at least twice and stirring. Combined with room temperature pressing molding and forced air drying process, it effectively solves the problems of filler agglomeration and poor interfacial bonding, ensures uniform dispersion and firm bonding of filler in matrix, and avoids complex equipment such as supercritical drying. The process is simple, low cost and easy to industrialize. The resulting composite insulation material has excellent thermal insulation performance, mechanical properties and hydrophobic properties. Attached Figure Description

[0024] Figure 1 This is a SEM image of the aerogel composite thermal insulation material prepared in Example 1 of the present invention. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0026] Existing aerogel composite insulation materials cannot simultaneously achieve low cost, low thermal conductivity, high mechanical strength, good interfacial compatibility and bonding strength of composite materials, as well as good hydrophobicity and long-term weather resistance.

[0027] The first aspect of this embodiment provides an aerogel composite thermal insulation material, which is prepared from the following raw materials in parts by weight: Polyvinyl alcohol: 5-10 parts; water: 80-120 parts; silica aerogel: 60-150 parts; inorganic particles: 50-120 parts; dispersant: 0.6-3.5 parts; wetting agent: 0.15-3 parts; coupling agent: 0.5-2 parts; wherein the inorganic particles are selected from at least one of hollow cenospheres and expanded perlite.

[0028] In this material, the nanoporous structure of silica aerogel interweaves with the micron-scale hollow structure of hollow perlite / expanded perlite, forming a dual low thermal conductivity network at multiple nano- and micron-scales. This effectively extends the heat conduction path and suppresses gas convection heat transfer. Simultaneously, the dispersant in the composite additives prevents filler particle agglomeration through steric hindrance, the wetting agent reduces the surface tension of the polyvinyl alcohol aqueous solution to improve wettability to hydrophobic aerogels and inorganic particles, and the coupling agent forms chemical bonds between the filler surface and the polyvinyl alcohol matrix, constructing a strong interfacial bonding layer. This results in a composite insulation material that, while significantly reducing the amount of silica aerogel used, possesses low thermal conductivity, high compressive strength, excellent interfacial bonding strength, good hydrophobic properties, and long-term weather resistance.

[0029] In some embodiments, the weight ratio of silica aerogel to inorganic particles is 1:1 to 1.5:1. Studies have found that the weight ratio of silica aerogel to inorganic particles is a key factor affecting the performance of aerogel thermal insulation composites. The nanoporous structure of silica aerogel and the micron-sized closed-cell hollow structure of hollow perlite / expanded perlite can form a nanoporous composite material. Research on a micron-scale dual low thermal conductivity network has revealed that if the ratio of the two components is too low, the continuous low thermal conductivity framework of the aerogel is excessively diluted, leading to an increase in thermal conductivity; conversely, if the ratio is too high, the compressive strength decreases, and the cost increases significantly. Maintaining the weight ratio of the two components within a reasonable range ensures that the thermal conductivity remains stable at 0.033-0.039 W·m. - ¹·K - ¹, and at the same time, the compressive strength can reach 0.70. The abrasive strength is 1.08 MPa, and the interfacial bonding strength and long-term weather resistance are synergistically improved, achieving an excellent balance between low thermal conductivity, high mechanical properties and low cost. For example, in some embodiments, the weight ratio of silica aerogel to inorganic particles is 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, and 1:1.5.

[0030] In some embodiments, the weight ratio of the dispersant, wetting agent, and coupling agent is (3-5):1:(1-3.5). Studies have found that when the weight ratio of the three is controlled within a suitable range, the dispersant, wetting agent, and coupling agent can exert a better synergistic effect. In this case, the dispersant (sodium polycarboxylate) effectively prevents the agglomeration of filler particles through steric hindrance, the wetting agent (AEO-9) minimizes the surface tension of the polyvinyl alcohol aqueous solution to fully wet the surface of the hydrophobic filler, and the coupling agent (KH-560) forms a dense chemical bond layer between the inorganic filler and the polyvinyl alcohol matrix. The synergistic effect of the three agents enables the filler to be uniformly dispersed in the matrix, significantly improves the interfacial bonding strength, and significantly reduces internal defects in the material. If the ratio deviates from this range, problems such as uneven filler dispersion, weakened interfacial bonding, decreased hydrophobicity, or increased thermal conductivity will occur, making it impossible to obtain excellent comprehensive performance simultaneously. For example, in some embodiments, the weight ratio of the dispersant, wetting agent and coupling agent can be 3:1:1, 3.5:1:1.2, 4:1:1.5, 4.5:1:2.5, 5:1:3.5, or any other ratio within the above range. All of these are feasible and can achieve significantly better dispersion, wetting and interfacial bonding effects than those outside the range, thereby ensuring that the composite insulation material has comprehensive properties such as low thermal conductivity, high compressive strength, good hydrophobicity and long-term weather resistance.

[0031] In some embodiments, the dispersant is sodium polycarboxylate, the wetting agent is AEO-9, and the coupling agent is KH-560. Through extensive experimental research, the inventors discovered that by selecting sodium polycarboxylate as the dispersant, AEO-9 as the wetting agent, and KH-560 as the coupling agent, a unique synergistic relationship is formed among the three, resulting in significantly superior overall performance compared to other similar alternatives. Specifically, the comb-like molecular structure of sodium polycarboxylate provides a strong steric hindrance effect, effectively preventing the aggregation of silica aerogel and hollow cenospheres / expanded perlite, ensuring uniform dispersion of the filler in the polyvinyl alcohol matrix. AEO-9 has a suitable hydrophilic-lipophilic balance (HLB value) and low surface tension, which can minimize the surface tension of the polyvinyl alcohol aqueous solution, allowing the matrix to fully wet the hydrophobic aerogel and inorganic particle surface, creating a uniform interfacial environment for the chemical bonding of the coupling agent. The specific combination of sodium polycarboxylate, AEO-9, and KH-560 is the key to maximizing the synergistic effect of the ternary additive system described in this invention and ensuring that the material has ultra-low thermal conductivity, high compressive strength, strong hydrophobicity, excellent interfacial bonding, and long-term weather resistance.

[0032] Sodium polycarboxylate is a comb-shaped anionic polymeric dispersant, its molecule consisting of a main chain with carboxyl and hydroxyl groups and polyether side chains. Preferably, the sodium polycarboxylate has a molecular weight of 10,000-15,000.

[0033] The second aspect of this embodiment provides a method for preparing the aerogel composite thermal insulation material as described above, comprising the following steps: Polyvinyl alcohol is added to water, heated and stirred to dissolve, resulting in a polyvinyl alcohol solution; Add wetting agent, dispersant and coupling agent to polyvinyl alcohol solution, stir and mix to obtain modified polyvinyl alcohol matrix solution; A composite filler is obtained by mixing silica aerogel with inorganic particles; The composite filler is added to the modified polyvinyl alcohol matrix solution in at least two batches and stirred to obtain the composite slurry. The composite slurry is poured into a mold and pressed at room temperature to obtain the initial blank. The initial preform is dried to obtain an aerogel composite insulation material.

[0034] The preparation method provided by this invention involves first pre-modifying the matrix by adding a wetting agent, dispersant, and coupling agent to a polyvinyl alcohol solution, and then adding a composite filler of silica aerogel and inorganic particles in at least two separate additions with stirring. Combined with room temperature pressing and forced-air drying processes, this method effectively solves the problems of filler agglomeration and poor interfacial bonding, ensuring uniform dispersion and firm bonding of the filler in the matrix. At the same time, it avoids complex equipment such as supercritical drying. The process is simple, low-cost, and easy to industrialize. The resulting composite insulation material has excellent thermal insulation performance, mechanical properties, and hydrophobic properties.

[0035] In some embodiments, during the preparation of the polyvinyl alcohol solution, the temperature is raised to 90℃-95℃ and stirred to dissolve the solution for 3-4 hours.

[0036] In some embodiments, during the preparation of the composite slurry, the modified polyvinyl alcohol matrix solution is added in two steps: first, 40% to 60% of the total weight of the composite filler is added and stirred for 5 to 10 minutes; second, the remaining composite filler is added and stirred for 10 to 15 minutes.

[0037] In some embodiments, during the initial blank preparation process, the pressing pressure is 3–5 MPa, and the holding time is 5–10 min.

[0038] In some embodiments, the initial blank is dried by forced air drying at a temperature of 60℃-70℃ for 18-24 hours.

[0039] Through extensive experimental research, the inventors discovered that using a forced-air drying temperature of 60℃-70℃ and controlling the drying time for 18-24 hours can ensure sufficient moisture evaporation while maximally preserving the integrity of the internal nano-micro multi-scale dual low thermal conductivity network structure of the material. This temperature range provides sufficient drying driving force to ensure uniform moisture escape from the blank, while avoiding the propagation of microcracks caused by slow moisture evaporation and uneven internal moisture distribution due to excessively low drying temperatures, thus preventing a significant increase in thermal conductivity. Simultaneously, the upper limit of this temperature, 70℃, is below the glass transition temperature range of polyvinyl alcohol, effectively preventing excessive shrinkage of the PVA matrix, pore structure collapse, and interface debonding caused by high temperatures, avoiding a significant decrease in compressive strength and long-term weather resistance degradation. Controlling the drying time to 18-24 hours ensures sufficient moisture removal while avoiding the efficiency reduction caused by excessively long drying times or the incomplete drying caused by excessively short drying times.

[0040] The aerogel composite insulation material described above, or the aerogel composite insulation material prepared according to the method described above, has a thermal conductivity of 0.033–0.039 W·m. -1 ·K -1The compressive strength is 0.70–1.08 MPa, and the water contact angle is 108–126°.

[0041] The third aspect of this embodiment provides the application of the above-described aerogel composite insulation material or the aerogel composite insulation material prepared by the above-described method in the fields of building insulation, cold chain logistics or pipeline insulation.

[0042] The aerogel composite insulation material provided by this invention has the advantages of ultra-low thermal conductivity, high compressive strength, excellent hydrophobic properties and long-term weather resistance. It can significantly reduce the heat loss of building exterior walls and roofs, cold chain logistics insulation boxes and industrial thermal pipelines. At the same time, it resists water vapor erosion and compressive load in the service environment, extends the service life of the insulation system, and can greatly reduce material costs. It provides an economical, efficient and durable solution for building energy conservation, cold chain transportation and pipeline insulation.

[0043] To better understand the technical solutions of the above embodiments, the following more detailed implementation examples are provided for further explanation.

[0044] The raw materials and their specifications used in the following examples and comparative examples are shown in Table 1.

[0045] Table 1 Raw materials and raw material specifications

[0046] Example 1 raw material By weight, it includes 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); 80 parts low thermal conductivity inorganic particles - hollow cenospheres; 2 parts dispersant (sodium polycarboxylate); 0.5 parts wetting agent (AEO-9); and 0.6 parts coupling agent (KH-560).

[0047] Preparation of aerogel composite thermal insulation materials S1, Preparation of PVA matrix solution: Polyvinyl alcohol (PVA) is slowly added to water, heated to 92°C, and stirred for 3.5 hours until the PVA is completely dissolved to form a uniform and transparent solution; then the solution is cooled to 80°C and set aside for later use.

[0048] S2. In the PVA solution obtained in S1, add wetting agent (AEO-9), dispersant (sodium polycarboxylate), and silane coupling agent (KH-560) in sequence according to the weight parts, and stir for 8 min to obtain a uniform modified PVA matrix solution.

[0049] S3. Mix silica aerogel (SA) with low thermal conductivity inorganic particles to obtain a composite filler; then stir and mix for 8 min to initially disperse the filler evenly and avoid agglomeration.

[0050] S4. Add the composite filler obtained in S3 to the matrix solution obtained in S2 in batches: First, add 50% of the total weight of the composite filler and stir for 8 minutes; then add the remaining filler and stir for 12 minutes to obtain the composite slurry. S5. Pour the obtained composite slurry into the mold and press it at room temperature: molding pressure: 4 MPa, holding time: 8 min, to obtain the initial blank.

[0051] S6. Place the blank in a forced-air drying oven and dry it at 65 ℃ for 20 h to obtain the finished aerogel composite thermal insulation material.

[0052] like Figure 1 As shown, the SEM image of the aerogel composite insulation material prepared in Example 1 shows that the larger particles are hollow cenospheres, while the smaller particles with small pores are aerogel powder. Figure 1 As can be seen, the aerogel particles and inorganic fillers have good compatibility, and a good bond is formed at the interface due to the composite additives.

[0053] Example 2 Example 2 uses the same preparation process as Example 1 to prepare aerogel composite insulation material.

[0054] The raw materials, by weight, include 5 parts polyvinyl alcohol (PVA); 80 parts water; 80 parts silica aerogel (SA); 70 parts low thermal conductivity inorganic particles - hollow cenospheres; 1.2 parts dispersant (sodium polycarboxylate); 0.3 parts wetting agent (AEO-9); and 0.5 parts coupling agent (KH-560).

[0055] Example 3 Example 3 uses the same preparation process as Example 1 to prepare aerogel composite insulation material.

[0056] The raw materials, by weight, include 10 parts polyvinyl alcohol (PVA); 120 parts water; 150 parts silica aerogel (SA); 100 parts low thermal conductivity inorganic particles - hollow cenospheres; 3 parts dispersant (sodium polycarboxylate); 1 part wetting agent (AEO-9); and 2 parts coupling agent (KH-560).

[0057] Example 4 Example 4 uses the same preparation process as Example 1 to prepare aerogel composite insulation material.

[0058] The raw materials, by weight, include 7 parts polyvinyl alcohol (PVA); 100 parts water; 110 parts silica aerogel (SA); 50 parts low thermal conductivity inorganic particles-expanded perlite; 2 parts dispersant (sodium polycarboxylate); 0.5 parts wetting agent (AEO-9); and 1 part coupling agent (KH-560).

[0059] Example 5 Example 5 uses the same preparation process as Example 1 to prepare aerogel composite insulation material.

[0060] The raw materials, by weight, include: 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); 40 parts low thermal conductivity inorganic particles - hollow cenospheres; 80 parts low thermal conductivity inorganic particles - expanded perlite; 2 parts dispersant (sodium polycarboxylate); 0.5 parts wetting agent (AEO-9); and 1 part coupling agent (KH-560).

[0061] Example 6 Example 6 uses the same preparation process as Example 1 to prepare aerogel composite insulation material.

[0062] The raw materials, by weight, include 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); 80 parts low thermal conductivity inorganic particles - hollow cenospheres; 1 part dispersant (sodium polycarboxylate); 0.3 parts wetting agent (AEO-9); and 0.5 parts coupling agent (KH-560).

[0063] Example 7 Example 7 uses the same preparation process as Example 1 to prepare aerogel composite insulation material.

[0064] The raw materials, by weight, include 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); 80 parts low thermal conductivity inorganic particles - hollow cenospheres; 3 parts dispersant (sodium polycarboxylate); 0.8 parts wetting agent (AEO-9); and 1.2 parts coupling agent (KH-560).

[0065] Example 8 Example 8 uses the same raw material weight and weight parts as Example 1, and only the process parameters of the preparation method are changed compared to Example 1.

[0066] Specific preparation process: S1, Preparation of PVA matrix solution: Polyvinyl alcohol (PVA) is slowly added to water, heated to 92°C, and stirred for 3.5 hours until the PVA is completely dissolved and a uniform, transparent solution is formed; then the temperature is lowered to 80°C for later use.

[0067] S2. In the PVA solution obtained in S1, add wetting agent (AEO-9), dispersant (sodium polycarboxylate), and silane coupling agent (KH-560) in sequence according to the weight parts, and stir for 8 min to obtain a uniform modified PVA matrix solution.

[0068] S3. Mix silica aerogel (SA) with low thermal conductivity inorganic particles to obtain a composite filler; then stir and mix for 8 min to initially disperse the filler evenly and avoid agglomeration.

[0069] S4. Add the composite filler obtained in S3 to the matrix solution obtained in S2 in batches: Add 40% of the total weight of the composite filler for the first time and stir for 5 minutes; add the remaining filler for the second time and stir for 15 minutes. S5. Pour the obtained composite slurry into the mold and press it at room temperature: molding pressure: 3MPa, holding time: 10 min, to obtain the initial blank.

[0070] S6. Place the blank in a forced-air drying oven and dry it at 60 ℃ for 24 h to obtain the finished aerogel composite thermal insulation material.

[0071] Example 9 Example 9 uses the same raw material weight and weight parts as Example 1, and only the process parameters of the preparation method are changed compared to Example 1.

[0072] Specific preparation process: S1, Preparation of PVA matrix solution: Polyvinyl alcohol (PVA) is slowly added to water, heated to 92°C, and stirred for 3.5 hours until the PVA is completely dissolved and a uniform, transparent solution is formed; then the temperature is lowered to 80°C for later use.

[0073] S2. In the PVA solution obtained in S1, add wetting agent (AEO-9), dispersant (sodium polycarboxylate), and silane coupling agent (KH-560) in sequence according to the weight parts, and stir for 8 min to obtain a uniform modified PVA matrix solution.

[0074] S3. Mix silica aerogel (SA) with low thermal conductivity inorganic particles to obtain a composite filler; then stir and mix for 8 min to initially disperse the filler evenly and avoid agglomeration.

[0075] S4. Add the composite filler obtained in S3 to the matrix solution obtained in S2 in batches: Add 60% of the total weight of the composite filler for the first time and stir for 10 minutes; add the remaining filler for the second time and stir for 10 minutes. S5. Pour the obtained composite slurry into the mold and press it at room temperature: molding pressure: 5 MPa, holding time: 5 min, to obtain the initial blank.

[0076] S6. Place the blank in a forced-air drying oven and dry it at 70 ℃ for 18 h to obtain the finished aerogel composite thermal insulation material.

[0077] Example 10 Example 10 uses the same preparation process as Example 1 to prepare aerogel composite insulation material.

[0078] The raw materials, by weight, include 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); 80 parts low thermal conductivity inorganic particles - hollow cenospheres; 1 part dispersant (sodium polycarboxylate); 0.2 parts wetting agent (AEO-9); and 0.5 parts coupling agent (KH-560).

[0079] Example 11 Example 11 uses the same preparation process as Example 1 to prepare aerogel composite insulation material.

[0080] The raw materials, by weight, include 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); 80 parts low thermal conductivity inorganic particles - hollow cenospheres; 3.4 parts dispersant (sodium polycarboxylate); 1.1 parts wetting agent (AEO-9); and 1.5 parts coupling agent (KH-560).

[0081] Example 12 Example 12 uses the same preparation process as Example 1 to prepare aerogel composite insulation material.

[0082] The raw materials, by weight, include 10 parts polyvinyl alcohol (PVA); 120 parts water; 150 parts silica aerogel (SA); 110 parts low thermal conductivity inorganic particles - hollow cenospheres; 3.3 parts dispersant (sodium polycarboxylate); 1.0 part wetting agent (AEO-9); and 1.7 parts coupling agent (KH-560).

[0083] Example 13 Example 13 uses the same preparation process as Example 1 to prepare aerogel composite insulation material.

[0084] The raw materials, by weight, include 5 parts polyvinyl alcohol (PVA); 80 parts water; 60 parts silica aerogel (SA); 50 parts low thermal conductivity inorganic particles - hollow cenospheres; 0.6 parts dispersant (sodium polycarboxylate); 0.15 parts wetting agent (AEO-9); and 0.5 parts coupling agent (KH-560).

[0085] Example 14 Raw materials (parts by weight) Polyvinyl alcohol (PVA): 5 parts; Water: 100 parts; Silica aerogel (SA): 150 parts; Hollow cenospheres: 80 parts; Dispersant (sodium polycarboxylate): 2 parts; Wetting agent (AEO-9): 0.5 parts; Coupling agent (KH-560): 0.6 parts; Preparation method: Same as in Example 1.

[0086] Example 15 Raw materials (parts by weight) Polyvinyl alcohol (PVA): 10 parts; water: 120 parts; silica aerogel (SA): 60 parts; hollow cenospheres: 80 parts; dispersant (sodium polycarboxylate): 2 parts; wetting agent (AEO-9): 0.5 parts; coupling agent (KH-560): 0.6 parts.

[0087] Preparation method: Same as in Example 1.

[0088] Comparative Example 1 Compared to Example 1, Comparative Example 1 did not include low thermal conductivity inorganic particles and composite additives.

[0089] Specifically, the raw materials include, by weight, 7 parts polyvinyl alcohol (PVA), 100 parts water, and 180 parts silica aerogel (SA).

[0090] The preparation method is as follows: Polyvinyl alcohol (PVA) is slowly added to water, heated to 92°C, and stirred for 3.5 hours until the PVA is completely dissolved and a uniform, transparent solution is formed; then the temperature is lowered to 80°C for later use.

[0091] Add silica aerogel to the polyvinyl alcohol solution in batches: First, add 50% of the total weight of silica aerogel and stir for 8 minutes; then add the remaining silica aerogel and stir for 12 minutes to obtain the composite slurry. The obtained composite slurry was poured into a mold and pressed at room temperature: molding pressure: 4 MPa, holding time: 8 min, to obtain the initial blank.

[0092] The blank was placed in a forced-air drying oven and dried at 65 ℃ for 20 h to obtain the thermal insulation material.

[0093] Comparative Example 2 Compared with Example 1, Comparative Example 2 replaced hollow cenospheres with an equal amount of calcium carbonate, while other raw materials and preparation methods remained the same.

[0094] By weight, it includes 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); 80 parts calcium carbonate; 2 parts dispersant (sodium polycarboxylate); 0.5 parts wetting agent (AEO-9); and 0.6 parts coupling agent (KH-560).

[0095] Preparation of aerogel composite thermal insulation materials S1, Preparation of PVA matrix solution: Polyvinyl alcohol (PVA) is slowly added to water, heated to 92°C, and stirred for 3.5 hours until the PVA is completely dissolved and a uniform, transparent solution is formed; then the temperature is lowered to 80°C for later use.

[0096] S2. Add additives sequentially according to the weight parts to the PVA solution obtained in S1, and stir for 8 min to obtain a uniform modified PVA matrix solution.

[0097] S3. Mix silica aerogel (SA) with calcium carbonate to obtain a composite filler; then stir and mix for 8 min to initially disperse the filler evenly and avoid agglomeration.

[0098] S4. Add the composite filler obtained in S3 to the matrix solution obtained in S2 in batches: First, add 50% of the total weight of the composite filler and stir for 8 minutes; then add the remaining filler and stir for 12 minutes to obtain the composite slurry. S5. Pour the obtained composite slurry into the mold and press it at room temperature: molding pressure: 4 MPa, holding time: 8 min, to obtain the initial blank.

[0099] S6. Place the blank in a forced-air drying oven and dry it at 65 ℃ for 20 h to obtain the finished aerogel composite thermal insulation material.

[0100] Comparative Example 3 Compared to Example 1, the difference is that no dispersant, wetting agent, or coupling agent is added. The raw material composition is as follows: 7 parts polyvinyl alcohol; 100 parts water; 100 parts silica aerogel; 80 parts hollow cenospheres.

[0101] In the preparation method, the steps of adding wetting agent, dispersant and coupling agent to polyvinyl alcohol solution are omitted, and the remaining operations (including polyvinyl alcohol dissolution, composite filler mixing, addition in two parts, pressing and molding, drying) are the same as in Example 1.

[0102] Comparative Example 4 Compared to Example 1, the difference is that only 2 parts of dispersant (sodium polycarboxylate) are added, and no wetting agent or coupling agent is added. The raw material composition is as follows: 7 parts polyvinyl alcohol; 100 parts water; 100 parts silica aerogel; 80 parts hollow cenospheres; 2 parts dispersant (sodium polycarboxylate).

[0103] In the preparation method, only the dispersant is added in the additive step, and no wetting agent or coupling agent is added. The rest of the operation is the same as in Example 1.

[0104] Comparative Example 5 Compared to Example 1, the difference is that only 0.5 parts of wetting agent (AEO-9) were added, and no dispersant or coupling agent was added. The raw material composition is as follows: 7 parts polyvinyl alcohol; 100 parts water; 100 parts silica aerogel; 80 parts hollow cenospheres; 0.5 parts wetting agent (AEO-9).

[0105] In the preparation method, wetting agent is added only in the additive step, and dispersant and coupling agent are not added. The rest of the operation is the same as in Example 1.

[0106] Comparative Example 6 Compared to Example 1, the difference is that only 0.6 parts of coupling agent (KH-560) were added, and no dispersant or wetting agent was added. The raw material composition is as follows: 7 parts polyvinyl alcohol; 100 parts water; 100 parts silica aerogel; 80 parts hollow cenospheres; 0.6 parts coupling agent (KH-560).

[0107] In the preparation method, only the coupling agent is added in the additive step, and no dispersant or wetting agent is added. The rest of the operation is the same as in Example 1.

[0108] Comparative Example 7 Compared to Example 1, the difference is that 2 parts of dispersant (sodium polycarboxylate) and 0.5 parts of wetting agent (AEO-9) were added, and no coupling agent was added. The raw material composition is as follows: 7 parts polyvinyl alcohol; 100 parts water; 100 parts silica aerogel; 80 parts hollow cenospheres; 2 parts dispersant (sodium polycarboxylate); 0.5 parts wetting agent (AEO-9).

[0109] In the preparation method, only the dispersant and wetting agent are added in the additive step, and no coupling agent is added. The rest of the operation is the same as in Example 1.

[0110] Comparative Example 8 Compared to Example 1, the difference is that 2 parts of dispersant (sodium polycarboxylate) and 0.6 parts of coupling agent (KH-560) were added, and no wetting agent was added. The raw material composition is as follows: 7 parts polyvinyl alcohol; 100 parts water; 100 parts silica aerogel; 80 parts hollow cenospheres; 2 parts dispersant (sodium polycarboxylate); 0.6 parts coupling agent (KH-560).

[0111] In the preparation method, only the dispersant and coupling agent are added in the additive step, and no wetting agent is added. The rest of the operation is the same as in Example 1.

[0112] Comparative Example 9 Compared to Example 1, the difference is that 0.5 parts of wetting agent (AEO-9) and 0.6 parts of coupling agent (KH-560) were added, but no dispersant was added. The raw material composition is as follows: 7 parts polyvinyl alcohol; 100 parts water; 100 parts silica aerogel; 80 parts hollow cenospheres; 0.5 parts wetting agent (AEO-9); 0.6 parts coupling agent (KH-560).

[0113] In the preparation method, wetting agent and coupling agent are added only in the additive step, and dispersant is not added. The rest of the operation is the same as in Example 1.

[0114] Comparative Example 10 Compared with Example 1, Comparative Example 10 only changed the coupling agent: KH-550 replaced KH-560. The compounding form of the three remained the same. The other raw materials and weight parts, and the preparation method were the same as in Example 1.

[0115] Comparative Example 11 Compared with Example 1, Comparative Example 11 only changed the dispersant: SDBS replaced sodium polycarboxylate, and the compounding form of the three remained the same. The other raw materials and weight parts, and the preparation method were the same as in Example 1.

[0116] Comparative Example 12 Compared with Example 1, Comparative Example 12 only changed the wetting agent: AEO-7 replaced AEO-9. The compounding form of the three remained the same. The other raw materials and weight parts, and the preparation method were the same as in Example 1.

[0117] Comparative Example 13 The raw materials are exactly the same as those in Example 1.

[0118] Except for the drying step, the preparation method is completely consistent with Example 1. The drying step is modified as follows: the initial blank is placed in an environment with room temperature (25°C) and relative humidity of 50% and dried naturally for 48 hours to obtain the thermal insulation material.

[0119] Comparative Example 14 The raw materials are exactly the same as those in Example 1.

[0120] Except for the drying step, the preparation method is completely consistent with Example 1. The drying step is modified as follows: the blank is placed in a forced-air drying oven and dried at 80°C for 18 h to obtain the finished aerogel composite thermal insulation material.

[0121] Comparative Example 15 Compared with Example 1, Comparative Example 15 only replaced the coupling agent with KH-570 instead of KH-560. All other raw materials, weight parts, and preparation methods were the same as in Example 1.

[0122] The raw materials, by weight, include 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); 80 parts hollow cenospheres; 2 parts dispersant (sodium polycarboxylate); 0.5 parts wetting agent (AEO-9); and 0.6 parts coupling agent (KH-570).

[0123] The preparation method is the same as in Example 1.

[0124] Comparative Example 16 Compared with Example 1, Comparative Example 16 only changed the dispersant from sodium polycarboxylate to sodium polyacrylate (molecular weight 3000-5000), while the other raw materials, weight parts, and preparation methods were the same as in Example 1.

[0125] The raw materials, by weight, include 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); 80 parts hollow cenospheres; 2 parts dispersant (sodium polyacrylate); 0.5 parts wetting agent (AEO-9); and 0.6 parts coupling agent (KH-560).

[0126] The preparation method is the same as in Example 1.

[0127] Comparative Example 17 Compared with Example 1, Comparative Example 17 only replaced the wetting agent with AEO-3 instead of AEO-9. All other raw materials, weight parts, and preparation methods were the same as in Example 1.

[0128] The raw materials, by weight, include 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); 80 parts hollow cenospheres; 2 parts dispersant (sodium polycarboxylate); 0.5 parts wetting agent (AEO-3); and 0.6 parts coupling agent (KH-560).

[0129] The preparation method is the same as in Example 1.

[0130] Comparative Example 18 Compared with Example 1, Comparative Example 18 only replaced the wetting agent AEO-9 with TX-10 (nonylphenol polyoxyethylene ether), while the other raw materials, weight parts, and preparation methods were the same as in Example 1.

[0131] The raw materials, by weight, include 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); 80 parts hollow cenospheres; 2 parts dispersant (sodium polycarboxylate); 0.5 parts wetting agent (TX-10); and 0.6 parts coupling agent (KH-560).

[0132] The preparation method is the same as in Example 1.

[0133] Comparative Example 19 Compared with Example 1, Comparative Example 19 only changed the inorganic filler from hollow cenospheres to solid glass microspheres, while the other raw materials, weight parts, and preparation methods were the same as in Example 1.

[0134] The raw materials, by weight, include 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); and 80 parts solid glass microspheres (thermal conductivity approximately 1.36 W·m). - ¹·K - ¹, particle size 20μm); dispersant (sodium polycarboxylate) 2 parts; wetting agent (AEO-9) 0.5 parts; coupling agent (KH-560) 0.6 parts.

[0135] The preparation method is the same as in Example 1.

[0136] Comparative Example 20 Compared with Example 1, Comparative Example 20 only replaced the inorganic filler with diatomaceous earth instead of hollow cenospheres; all other raw materials, weight parts, and preparation methods were the same as in Example 1.

[0137] The raw materials, by weight, include 7 parts polyvinyl alcohol (PVA); 100 parts water; 100 parts silica aerogel (SA); and 80 parts diatomaceous earth (thermal conductivity 0.13–0.20 W·m at 400℃). - ¹·K - ¹, bulk density 0.34~0.65 g / cm³); dispersant (sodium polycarboxylate) 2 parts; wetting agent (AEO-9) 0.5 parts; coupling agent (KH-560) 0.6 parts.

[0138] The preparation method is the same as in Example 1.

[0139] Comparative Example 21 Compared to Example 1, Comparative Example 21 replaced the matrix with polyvinyl alcohol (PVA) with epoxy resin (E-51 type), and the addition of wetting agent AEO-9 was removed (because the epoxy resin system is a solvent-free system and no wetting agent is needed), while keeping the amounts of dispersant and coupling agent unchanged.

[0140] The raw materials, by weight, include 15 parts epoxy resin (E-51 type); 7.5 parts curing agent (polyamide) (epoxy resin: curing agent = 2:1); 100 parts silica aerogel (SA); 80 parts hollow cenospheres; 2 parts dispersant (sodium polycarboxylate); and 0.6 parts coupling agent (KH-560).

[0141] Preparation method: Epoxy resin and curing agent are mixed evenly at a ratio of 2:1, and dispersant and coupling agent are added and stirred for 8 min; silica aerogel and hollow cenospheres are mixed and dispersed for 8 min; composite filler is added to the resin mixture in batches, with 50% added first and stirred for 8 min, and the remaining filler added second and stirred for 12 min; the composite slurry is poured into a mold and pressed into shape at room temperature under a pressure of 4 MPa for 8 min; the green body is cured at 80℃ for 24 h to obtain the thermal insulation material.

[0142] Comparative Example 22 Compared to Example 1, Comparative Example 22 replaced the matrix with polyvinyl alcohol (PVA) with a silicate cement-based cementitious material system, while keeping the types and amounts of composite fillers and composite additives the same as in Example 1.

[0143] The raw materials, by weight, include 40 parts of silicate cement (PO 42.5); 20 parts of water; 100 parts of silica aerogel (SA); 80 parts of hollow cenospheres; 2 parts of dispersant (sodium polycarboxylate); 0.5 parts of wetting agent (AEO-9); and 0.6 parts of coupling agent (KH-560).

[0144] Preparation method: Silicate cement and water are mixed evenly, and wetting agent, dispersant and coupling agent are added and stirred for 8 min; silica aerogel and hollow cenospheres are mixed and dispersed for 8 min; composite filler is added to cement slurry in batches, 50% is added first and stirred for 8 min, and the remaining filler is added second and stirred for 12 min; composite slurry is poured into mold and pressed into shape at room temperature, pressure 4 MPa, and held for 8 min; the green body is cured for 28 days under standard curing conditions (20±2℃, RH≥95%) to obtain thermal insulation material.

[0145] test The performance of the thermal insulation materials prepared in Examples 1-13 and Comparative Examples 1-14 was tested, and the test results are shown in Table 3.

[0146] The test methods are shown in Table 2.

[0147] Long-term weather resistance (thermal conductivity retention rate, %) = (thermal conductivity after 50 high and low temperature cycles / initial thermal conductivity) × 100%.

[0148] Table 2 Test Conditions

[0149] Table 3 Comprehensive Performance of Thermal Insulation Materials

[0150] As shown in Table 3, the aerogel composite insulation materials prepared using the technical solution of this invention in Examples 1-3 exhibit ultra-low thermal conductivity, with thermal conductivity coefficients consistently ranging from 0.033 to 0.039 W. m -1 K -1 Within the scope. This invention selects the nanoscale porous structure of silica aerogel and the micron-scale hollow structure of hollow beads / expanded perlite to form a nano-scale composite. The micron-scale dual low thermal conductivity network, with its interwoven structure, effectively extends the heat conduction path and suppresses gas convection heat transfer. Simultaneously, the synergistic effect of composite additives solves the problem of filler agglomeration: sodium polycarboxylate, through steric hindrance, ensures uniform dispersion of the filler within the PVA matrix, avoiding heat conduction shortcuts formed by agglomeration. (AEO) The high efficiency of wetting with 9 allows the matrix and filler to fully combine, ensuring uniform thermal resistance distribution and ultimately achieving ultra-low and stable thermal conductivity.

[0151] The thermal conductivity of the comparative examples was significantly higher than that of the examples, and showed a clear gradient correlation with the variable: Comparative Example 1 (without inorganic particles) had a thermal conductivity of 0.052 W. m -1 K -1 The thermal conductivity is the highest in the entire series. This is because single silica aerogels are prone to agglomeration, making it impossible to form a multi-scale low thermal conductivity network. The heat conduction path is short, and there are no inorganic particles to share the thermal resistance, resulting in a significant increase in heat conduction efficiency. Comparative Example 2 (calcium carbonate replacing low thermal conductivity inorganic particles): Thermal conductivity 0.041 W. m - ¹ K - ¹, because calcium carbonate is a highly thermally conductive inorganic filler (thermal conductivity 0.15 W / m²). m - ¹ K - ¹), disrupting the continuity of the low thermal conductivity network, becoming a heat conduction channel, leading to a significant deterioration in thermal conductivity; Comparative Example 3 (without composite additives): thermal conductivity 0.044 W m - ¹ K - ¹, due to severe agglomeration of the filler, a large number of dense heat conduction regions are formed inside, resulting in uneven thermal resistance distribution and an inability to fully utilize the low thermal conductivity advantages of aerogel and inorganic particles; single / pair additive comparison ratio (4 9): Thermal conductivity 0.039~0.050 W m - ¹ K - ¹, a single additive or a combination of two additives cannot simultaneously solve the three major problems of dispersion, wetting, and interfacial bonding. The filler still exhibits localized agglomeration, the integrity of the low thermal conductivity network is compromised, and the thermal conductivity is significantly reduced compared to the example. The additive types in the comparative example (10...) 12): Thermal conductivity 0.038~0.039 W m - ¹ K - ¹, Although it is a combination of three, the replaced KH 550, SDBS, AEO 7. The synergistic dispersion and wetting effect of the original composite additives could not be achieved, the uniformity of filler dispersion decreased slightly, and the thermal conductivity was slightly higher than the core ratio of the example.

[0152] Comparative Example 13 (drying at room temperature): Thermal conductivity increased to 0.055 W. m - ¹ K - ¹ Due to uneven moisture evaporation, numerous microcracks formed in the green body, disrupting the dual low thermal conductivity network and significantly shortening the heat conduction path; Comparative Example 14 (drying at 80℃): thermal conductivity 0.045 W m - ¹ K - ¹, due to the high-temperature shrinkage of the PVA matrix, the internal pore structure collapses, resulting in a significant reduction in thermal resistance.

[0153] As shown in Table 3, the aerogel composite insulation materials prepared using the technical solution of this invention in Examples 1-3 have good mechanical properties, with compressive strength reaching 0.70-1.08 MPa. Among them, Example 10 has the highest compressive strength of 1.08 MPa, while Example 13 has a compressive strength of 0.72 MPa. Even Example 8, which has the lower limit of process parameters, has a compressive strength of 0.70 MPa, which is much higher than the compressive strength of aerogel composite insulation materials in the prior art (≤0.20 MPa).

[0154] This invention enhances compressive strength through a dual approach: optimized filler structure and strengthened interfacial bonding. Firstly, the micron-sized particles of hollow perlite / expanded perlite and the nano-sized particles of silica aerogel form a dense and stable packing structure, effectively dispersing stress and avoiding stress concentration caused by the porous structure of a single aerogel. Secondly, the KH in the composite additive... The 560 coupling agent forms chemical bonds between the silanol groups on the surface of the inorganic filler and the hydroxyl groups of the PVA matrix, constructing a strong interfacial bonding layer. Simultaneously, the dispersing effect of sodium polycarboxylate increases the effective contact area between the filler and the matrix. (AEO) The wetting effect of 9 makes the chemical bonding more uniform, allowing stress to be smoothly transferred between the filler and the matrix, ultimately resulting in a significant improvement in mechanical strength.

[0155] Comparative Example 3 (without composite additives): compressive strength 0.58 MPa. Due to the lack of chemical bonding from the coupling agent, the filler and matrix are only physically bonded, resulting in extremely weak interfacial adhesion. Furthermore, filler agglomeration leads to stress concentration, making it prone to cracking at the interface under pressure. Comparative Example 2 (calcium carbonate replacing low thermal conductivity inorganic particles): compressive strength 0.63 MPa. Because calcium carbonate lacks silanol groups, KH... 560 cannot form chemical bonds with it, and the particle size matching between calcium carbonate and silica aerogel is poor, resulting in a loose packing structure and low stress transfer efficiency; single additive comparative ratio (4 6): Compressive strength 0.66~0.92 MPa, only able to solve a single problem (such as only KH) 560 can slightly improve interfacial bonding, but it cannot solve the stress concentration problem caused by filler agglomeration, and cannot achieve effective stress dispersion and transfer; the two additives comparison ratio (7 9): Compressive strength is 0.67–0.77 MPa, which is an improvement over single additives, but due to the lack of synergistic effect from a particular additive, interfacial bonding or filler dispersion still has defects (e.g., comparative example 7 without coupling agent has weak interfacial bonding); comparative example 10 with different additive types 12): Compressive strength 0.73~0.75 MPa, due to the replacement coupling agent (KH) 550) The dispersant (SDBS) could not form strong chemical bonds or be efficiently dispersed, resulting in a decrease in interfacial bonding strength and filler packing uniformity, leading to a lower compressive strength than in the examples; Comparative Example 13 (drying at room temperature): compressive strength was only 0.55 MPa, with dense microcracks inside the green body, making it prone to fracture under stress; Comparative Example 14 (drying at 80°C): compressive strength was 0.52 MPa, which is the lowest level in the entire series. High temperature caused interfacial debonding and matrix embrittlement, resulting in a significant deterioration in mechanical properties.

[0156] As shown in Table 3, the aerogel composite insulation materials prepared using the technical solution of this invention in Examples 1-3 exhibit excellent hydrophobicity, with water contact angles all within the range of 108–126°. The hydrophobic performance of this invention stems from the synergistic effect of the low surface energy of the aerogel itself and the interfacial modification by the composite additives: the silica aerogel surface is rich in hydrophobic groups, and its nanoporous structure forms a micro-nano-scale rough surface, which can create an interfacial state similar to an air cushion, significantly reducing surface wettability; simultaneously, KH… The 560 coupling agent forms an organic modified layer on the surface of the filler and the matrix, further reducing the surface free energy of the material, while AEO... The high efficiency of 9 allows the modified layer to be evenly covered on the material surface, avoiding defects in the modified layer caused by insufficient wettability, and ultimately achieving strong hydrophobic properties.

[0157] Comparative Example 3 (without composite additives): The water contact angle of 90° was the lowest in the entire series, due to the absence of KH. The interface modification of 560 resulted in the material surface consisting only of the original hydrophobic groups of the aerogel. Furthermore, filler agglomeration destroyed the surface rough structure, preventing the formation of an "air cushion" effect and significantly improving surface hydrophilicity. Comparative Example 2 (calcium carbonate replacing low thermal conductivity inorganic particles): water contact angle was 95°. Because calcium carbonate is a hydrophilic filler, and its particles destroyed the micro-nano rough structure of the aerogel, the material surface became denser, significantly reducing hydrophobic properties. Comparative Example 4 (single dispersant): water contact angle was only 93°. Due to the lack of synergy between wetting agent and coupling agent, a uniform interface modification layer could not be formed, and surface wettability was not effectively improved. Comparative Example (10) with different additive types: 12): Water contact angle 102–108°, due to the replacement of KH 550, AEO 7. Unable to form an efficient interface modification layer (such as KH) 550 is easily hydrolyzed in aqueous systems, resulting in poor modification effects; AEO 7. Insufficient wettability and uneven distribution of modified layer) The hydrophobicity is significantly reduced compared with the example; Comparative Examples 13 and 14: The water contact angles are 94° and 96° respectively. Due to improper drying, the surface hydrophobic structure is damaged, the modified layer is discontinuous, and the hydrophobicity is significantly reduced.

[0158] As shown in Table 3, the aerogel composite insulation materials prepared using the technical solution of this invention in Examples 1-3 exhibit good flame retardant properties, with an oxygen index of 28.5–31.2%, in accordance with GB / T 2406.2. According to the 2009 standard, an oxygen index ≥ 28% is considered a flame-retardant material. Example 13 has an oxygen index of 28.6%, while the material of this invention has an oxygen index of up to 31.2%, exhibiting excellent flame-retardant properties and meeting the fire safety requirements of buildings, industrial pipelines, and other fields.

[0159] The flame-retardant properties of the material in this invention stem from the thermal stability of the inorganic components and the inhibition of thermal conductivity by the porous structure. Furthermore, the dispersing effect of the composite additives further enhances the flame-retardant effect: both silica aerogel and hollow perlite / expanded perlite are inorganic non-metallic fillers that do not participate in combustion at high temperatures, do not produce toxic gases, and can form a continuous, thermally stable framework within the material, delaying the thermal decomposition process of the matrix; the nano-structure formed by the two... The micron-porous structure can effectively reduce the heat transfer rate and inhibit the spread of combustion flames. In addition, the dispersing effect of composite additives allows inorganic components to be evenly distributed in the matrix, forming a continuous flame-retardant barrier, avoiding the breakage of the flame-retardant barrier caused by filler agglomeration, and further improving the flame-retardant performance.

[0160] The oxygen indices of the comparative examples were all in the range of 25.5% to 28.5%, and their flame retardant performance was weaker than that of the examples. The core reason was the discontinuity of the thermally stable skeleton or the defect of the flame retardant barrier: Comparative Example 3 (without composite additives): The oxygen index of 25.5% was the lowest in the entire series. Due to the agglomeration of fillers, the inorganic components were unevenly distributed, the thermally stable skeleton was broken, and a continuous flame retardant barrier could not be formed, making it easy for heat to transfer and for flames to spread; Comparative Example 2 (calcium carbonate replacing low thermal conductivity inorganic particles): The oxygen index was 27.2%. Because the thermal stability of calcium carbonate is lower than that of hollow cenospheres / expanded perlite, it is easy to undergo thermal decomposition at high temperatures, which destroys the continuity of the thermally stable skeleton; Single / pair additive comparative examples (4 9): Oxygen index 26.2-28.5%, due to insufficient filler dispersion or wetting, uneven distribution of inorganic components, local defects in the flame retardant barrier, and decreased flame retardant effect; Comparative example of additive type replacement (10 12): Oxygen index 28.2-28.5%. Although it is a compound of three, the synergistic dispersion effect of the additives is reduced, the uniformity of inorganic component distribution is slightly reduced, the continuity of the flame retardant barrier is slightly poor, and the oxygen index is slightly lower than that of the example. Comparative Examples 13 and 14: Oxygen indices are 26.8% and 27.0% respectively. Due to structural defects, the flame retardant skeleton is discontinuous, and the flame retardant performance is significantly reduced.

[0161] As shown in Table 3, the aerogel composite insulation materials prepared using the technical solution of this invention in Examples 1-3 exhibit good interfacial strength, reaching 0.55–0.80 MPa. Example 10, at 0.80 MPa, has the highest strength across the entire series, while Example 13, with an interfacial bonding strength of 0.56 MPa, significantly exceeds that of all comparative examples. This invention effectively solves the problem of inorganic fillers through the synergistic effect of composite additives. The interfacial incompatibility of the organic matrix was overcome, enabling a close bond between the two.

[0162] Interfacial bonding strength is one of the core performance indicators of this invention, and its superior performance is primarily attributed to KH. Chemical bonding of 560 with sodium polycarboxylate and AEO Synergistic effects of 9: KH The siloxane groups in the 560 molecule can undergo condensation reactions with the silanol groups on the surface of silica aerogel, hollow cenospheres / expanded perlite, and also react with the hydroxyl groups of the PVA matrix, forming a stable chemical bond layer between the inorganic filler and the organic matrix, rather than a simple physical bond; the dispersing effect of sodium polycarboxylate ensures uniform dispersion of the filler, increases the effective contact area between the filler and the matrix, and allows for more complete chemical bonding; AEO The wetting effect of 9 reduces the surface tension of the matrix, making KH 560 can fully penetrate the filler surface, avoiding chemical bonding defects caused by insufficient wettability. The three work together to significantly improve the interfacial bonding strength.

[0163] The interfacial bonding strength of the comparative examples all ranged from 0.38 to 0.58 MPa, primarily due to the lack of chemical bonding or insufficient chemical bonding. Comparative Example 3 (without composite additives): its interfacial bonding strength of 0.38 MPa was the lowest in the entire series, due to the absence of KH. The chemical bonding of 560 indicates that the filler and matrix are only physically bonded, resulting in extremely weak interfacial bonding. Comparative Example 2 (calcium carbonate replacing low thermal conductivity inorganic particles): interfacial bonding strength is 0.42 MPa. This is because calcium carbonate lacks silanol groups, and KH... 560 cannot undergo a condensation reaction with it, but can only form chemical bonds with aerogel, resulting in an incomplete interfacial bonding layer; single additive comparative example (4 6) Interfacial bonding strength 0.40~0.55 MPa, only KH 560 can slightly improve interfacial bonding, but due to the lack of synergistic effects from dispersants and wetting agents, chemical bonding is insufficient; other single additives have no interfacial modification effect; comparative ratio of two additives (7 9): The interfacial bonding strength is 0.45–0.55 MPa. Due to the lack of synergistic effect of a certain additive, the sufficiency or uniformity of chemical bonding decreases (e.g., in Comparative Example 8 without a wetting agent, KH). 560 cannot penetrate sufficiently, chemical bonding is inadequate; additive type replacement comparative example (10) 12): Interface bonding strength 0.48–0.50 MPa, due to the replacement of KH 550 could not form a stable chemical bond with the matrix, and the strength of the interfacial bonding layer decreased significantly; Comparative Examples 13 and 14: the interfacial bonding strength was only 0.41 MPa and 0.39 MPa, respectively. Improper drying led to severe debonding of the interface and a significant reduction in bonding strength.

[0164] As shown in Table 3, the aerogel composite insulation materials prepared using the technical solution of this invention in Examples 1-3 exhibit good long-term weather resistance. Example 1 The long-term weather resistance (thermal conductivity retention rate after 50 high and low temperature cycles) of the composite thermal insulation material prepared by 13 is 82-97%, with Example 11 reaching 97%, the highest in the entire series, and Example 13 having a weather resistance of 83%. Even Example 8, which has the lower limit of process parameters, has a retention rate of 82%. The material of the present invention can maintain stable structure and performance in harsh environments with alternating high and low temperatures, and has excellent long-term service performance.

[0165] The long-term weather resistance of the material of this invention is a comprehensive reflection of its hydrophobic properties, interfacial bonding strength, and filler chemical stability, and is the core verification of the material's overall performance: First, the material's strong hydrophobic properties (water contact angle 108-126°) effectively prevent water from penetrating into the material's interior, avoiding freeze-thaw expansion of water during high and low temperature cycles, which could lead to microcracks inside the material; Second, the high interfacial bonding strength effectively inhibits the generation and propagation of microcracks, avoiding material structure deterioration due to interfacial debonding; Third, both silica aerogel and hollow cenospheres / expanded perlite are chemically stable inorganic components that will not degrade or deform in alternating high and low temperature environments, ensuring the long-term stability of the material's skeleton; In addition, the dispersing effect of the composite additives makes the internal structure of the material uniform and free of obvious internal defects, further improving the material's weather resistance stability.

[0166] The long-term weather resistance of the comparative examples was all in the range of 74-84%, far lower than that of the examples. The core reason was that the material structure was prone to deterioration during high and low temperature cycling: Comparative Example 3 (without composite additives): The long-term weather resistance of 75% was the lowest in the entire series. Due to poor hydrophobicity and low interfacial bonding strength, moisture easily penetrated and the interface was prone to debonding. After high and low temperature cycling, a large number of microcracks were generated inside the material, the structure was severely deteriorated, and the thermal conductivity was greatly reduced; Comparative Example 2 (calcium carbonate replaced low thermal conductivity inorganic particles): The long-term weather resistance was 78%. Due to poor hydrophobicity and low compatibility between the filler and the matrix, calcium carbonate and aerogel were prone to peeling after high and low temperature cycling, the material structure was loose, and the thermal conductivity deteriorated rapidly; Single / pair additive comparative examples (4 9): Long-term weather resistance is 77-84%. Due to shortcomings in hydrophobicity and interfacial bonding strength, the material will develop local microcracks or interfacial debonding after high and low temperature cycling, resulting in a certain degree of performance degradation; Comparative ratio of additive type replacement (10) 12): Long-term weather resistance is 80-81%. Due to the decrease in hydrophobic properties and interfacial bonding strength compared to the example, a small number of microcracks will be generated inside the material after high and low temperature cycling. The thermal conductivity retention rate is lower than that of the example. Comparative Examples 13 and 14: Weather resistance is only 76% and 74%, respectively. Microcracks and interfacial debonding expand rapidly during cycling, and the performance degradation is the most significant.

[0167] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An aerogel composite thermal insulation material, characterized in that, It is prepared from the following raw materials in parts by weight: 5-10 parts of polyvinyl alcohol; 80-120 parts water; 60-150 parts of silica aerogel; 50-120 parts of inorganic particles; Dispersant 0.6–3.5 parts; Wetting agent 0.15–3 parts; 0.5 to 2 parts of coupling agent; The inorganic particles are selected from at least one of hollow cenospheres and expanded perlite.

2. The aerogel composite thermal insulation material according to claim 1, characterized in that, The weight ratio of silica aerogel to inorganic particles is 1:1 to 1.5:

1.

3. The aerogel composite thermal insulation material according to claim 1, characterized in that, The weight ratio of the dispersant, wetting agent and coupling agent is (3-5):1:(1-3.5).

4. The aerogel composite thermal insulation material according to any one of claims 1-3, characterized in that, The dispersant is sodium polycarboxylate, the wetting agent is AEO-9, and the coupling agent is KH-560.

5. A method for preparing an aerogel composite thermal insulation material as described in any one of claims 1-4, characterized in that, Includes the following steps: Polyvinyl alcohol is added to water, heated and stirred to dissolve, resulting in a polyvinyl alcohol solution; Add wetting agent, dispersant and coupling agent to polyvinyl alcohol solution, stir and mix to obtain modified polyvinyl alcohol matrix solution; A composite filler is obtained by mixing silica aerogel with inorganic particles; The composite filler is added to the modified polyvinyl alcohol matrix solution in at least two batches and stirred to obtain the composite slurry. The composite slurry is poured into a mold and pressed at room temperature to obtain the initial blank. The initial preform is dried to obtain an aerogel composite insulation material.

6. The method for preparing the aerogel composite thermal insulation material according to claim 5, characterized in that, During the preparation of the polyvinyl alcohol solution, the temperature is raised to 90℃-95℃ and stirred to dissolve for 3-4 hours.

7. The preparation method according to claim 5, characterized in that, During the preparation of the composite slurry, the modified polyvinyl alcohol matrix solution is added in two stages: the first stage adds 40% to 60% of the total weight of the composite filler and stirs for 5 to 10 minutes; the second stage adds the remaining composite filler and stirs for 10 to 15 minutes.

8. The preparation method according to claim 5, characterized in that, During the initial blank preparation process, the pressing pressure is 3-5 MPa, and the holding time is 5-10 min; And / or, the initial blank is dried by forced air drying at a temperature of 60℃-70℃ for 18-24 hours.

9. The aerogel composite thermal insulation material according to any one of claims 1-4, or the aerogel composite thermal insulation material prepared by the preparation method according to any one of claims 5-8, characterized in that, The thermal conductivity of the aerogel composite insulation material is 0.033–0.039 W·m. - ¹·K - ¹, with a compressive strength of 0.70–1.08 MPa and a water contact angle of 108–126°.

10. The application of the aerogel composite insulation material according to any one of claims 1-4 or the aerogel composite insulation material prepared by the preparation method according to any one of claims 5-8 in the fields of building insulation, cold chain logistics or pipeline insulation.

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