Heat-insulating gel as well as preparation method and application thereof

Abstract

The invention provides a heat-insulating gel and a preparation method and application thereof, the heat-insulating gel is prepared from a solid-phase raw material and a liquid-phase raw material, the solid-phase raw material comprises closed perlite, expanded perlite, hollow glass beads, hydroxyethyl cellulose and polypropylene fiber; the liquid-phase raw materials comprise silicone acrylic emulsion, a silane coupling agent and aerogel slurry. The aerogel slurry can be fully subjected to interface bonding with the porous perlite matrix in the solid-phase raw material by utilizing the excellent dispersity of the aerogel slurry, so that an excellent micro-nano pore heat insulation network is formed, and the heat conductivity coefficient of the product is greatly reduced. Therefore, the thermal insulation gel prepared by the invention has the characteristics of low heat conductivity, low density, high flame retardance and high bonding strength, and effectively relieves the defect that a traditional building external wall thermal insulation material cannot give consideration to excellent mechanical-thermal properties at the same time.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation materials technology, and in particular to a thermal insulation gel, its preparation method and application. Background Technology

[0002] Using high-performance thermal insulation materials is an effective way to reduce building energy consumption. However, the thermal conductivity of commonly available commercially available thermal insulation gel materials is typically >0.065 W / m·K and the density is >600 kg / m³. 3 With a bonding strength in the range of 0.3-1.0 MPa, it often has the problems of high thermal conductivity and density, and poor bonding strength, which makes it difficult to meet the requirements of some building fields for thermal insulation building materials to have excellent mechanical and thermal performance.

[0003] Based on this, technicians have proposed certain improvement measures. However, reducing thermal conductivity often requires the introduction of more porous, lightweight, low-thermal-conductivity fillers. This method often introduces more defects into the material, leading to a decrease in its bonding strength. On the other hand, increasing bonding strength often introduces more high-viscosity organic phases, which often leads to an increase in density and thermal conductivity, and a reduction in the material's fire resistance rating. Therefore, in the current field of thermal insulation materials, there is a technical contradiction that makes it difficult to simultaneously achieve low thermal conductivity, high bonding strength, low density, and excellent fire resistance.

[0004] In recent years, silica aerogel has been widely used in exterior wall insulation mortars due to its low density, high porosity, and low thermal conductivity. However, the current market generally uses unmodified silica aerogel powder as the main raw material, and prepares insulation materials by conventional compounding with lightweight hollow vitrified microspheres and auxiliary insulation fillers such as perlite, combined with film-forming substances and dispersion media. However, this technical solution has significant drawbacks: the aerogel powder is not surface-functionalized during the slurry preparation process, and is directly introduced into the system through a high-shear dispersion process. The unmodified silica aerogel powder severely damages the nanoporous framework of the insulation gel and causes phase separation between it and the organic matrix material. This results in defects such as poor nanostructure integrity and deteriorated interfacial compatibility when silica aerogel is applied to insulation materials, leading to unstable mechanical and thermal properties of the insulation materials. Therefore, it is both necessary and urgent to research and develop a silica aerogel insulation gel material with low thermal conductivity, low density, high flame retardancy, and high bonding strength.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The primary objective of this invention is to provide a thermal insulation gel that features low thermal conductivity, low density, high flame retardancy, and high bonding strength, effectively overcoming the shortcomings of traditional building exterior wall insulation materials that cannot simultaneously achieve excellent mechanical and thermal performance.

[0007] A second objective of this invention is to provide a method for preparing a heat-insulating gel.

[0008] A third objective of this invention is to provide an application of a heat-insulating gel.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: This invention provides a thermal insulation gel, which is prepared from two parts: a solid phase raw material and a liquid phase raw material, wherein: The solid raw materials include: closed perlite, expanded perlite, hollow vitrified microspheres, hydroxyethyl cellulose, and polypropylene fiber; The liquid phase raw materials include: silicone-acrylic emulsion, silane coupling agent and aerogel slurry; the aerogel slurry has a thermal conductivity of 0.018~0.022W / (m•K), a particle diameter of 15~30 μm, a solid content of 10~15%, and a viscosity of 30000~40000cp.

[0010] Furthermore, in the solid phase raw material, the mass ratio of closed perlite, expanded perlite, hollow vitrified microspheres, hydroxyethyl cellulose, and polypropylene fiber is (10.5~22):(20~43):(2~8):(1~5):(1~4). Furthermore, the liquid phase raw material also includes: wetting agent, defoamer and water; Preferably, the wetting agent comprises at least one of sodium dodecyl sulfate, alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and polyethylene glycol ester; Preferably, the defoamer includes at least one of silicone defoamer, polyether defoamer, mineral oil defoamer, and polyether-modified silicone defoamer.

[0011] Furthermore, in the liquid phase raw material, the mass ratio of water, silicone-acrylic emulsion, silane coupling agent, wetting agent, defoamer, and aerogel slurry is (35~65):(35~65):(2~8):(1~4):(0.5~3.5):(196.5~350). Preferably, the silane coupling agent is silane coupling agent KH550.

[0012] This invention provides a method for preparing a heat-insulating gel, the method comprising: S1: Mix the solid raw material and the liquid raw material separately to obtain solid material and liquid material; S2: Add the liquid phase material to the solid phase material and stir to mix, thus obtaining a gel-like intermediate; S3: Curing and drying the gel-like intermediate to obtain the heat-insulating gel.

[0013] Furthermore, the mass ratio of liquid phase material to solid phase material in S2 is 45.5~65:300~495.5.

[0014] Furthermore, in step S2, the stirring speed is 140~150 rpm and the time is 5~15 min.

[0015] Furthermore, the curing temperature in S3 is 20~30℃, the relative humidity is 40~60%, and the time is 2~3 days.

[0016] Furthermore, the drying in S3 is gradient drying; Preferably, the gradient drying temperature is 40, 80, and 105°C, and the duration of each gradient is 0.5 to 3.5 h.

[0017] The application of the above-mentioned thermal insulation gel provided by the present invention in the preparation of thermal insulation building materials.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The thermal insulation gel provided by this invention is prepared from two parts: a solid phase raw material and a liquid phase raw material. The solid phase raw material includes closed-cell perlite, expanded perlite, hollow vitrified microspheres, hydroxyethyl cellulose, and polypropylene fibers. The liquid phase raw material includes silicone-acrylic emulsion, a silane coupling agent, and an aerogel slurry. This application utilizes the excellent dispersibility of the aerogel slurry, allowing it to fully bond with the porous perlite matrix in the solid phase raw material to form an excellent micro-nanoporous thermal insulation network, significantly reducing the thermal conductivity of the product. Therefore, the thermal insulation gel prepared by this invention has the characteristics of low thermal conductivity, low density, high flame retardancy, and high adhesive strength, overcoming the shortcomings of traditional building exterior wall insulation materials that cannot simultaneously achieve excellent mechanical and thermal properties, and providing a new approach for the preparation of advanced thermal insulation gel products.

[0019] The present invention provides a method for preparing a thermal insulation gel. The method involves first mixing solid and liquid raw materials separately to obtain a solid material and a liquid material. Then, the liquid material is added to the solid material and stirred to obtain a gel-like intermediate. Finally, the intermediate is cured and dried to obtain the thermal insulation gel. This preparation method has the advantages of simple processing and ease of operation.

[0020] The thermal insulation gel provided by this invention can be widely used in the preparation process of thermal insulation building materials. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 Macroscopic morphology of the thermal conductivity test sample of the thermal insulation gel provided in Example 1 of the present invention; Figure 2 Macroscopic morphology of the bonding strength test sample of the thermal insulation gel provided in Example 1 of the present invention; Figure 3 The scanning electron microscope image of the thermal insulation gel of Example 1 provided in Experimental Example 1 of the present invention; Figure 4 The scanning electron microscope image of the thermal insulation gel of Example 2 provided in Experimental Example 1 of the present invention; Figure 5 The image is a scanning electron microscope image of the thermal insulation gel of Example 3 provided in Experimental Example 1 of the present invention. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] According to one aspect of the present invention, a thermal insulating gel is prepared from two parts: a solid phase raw material and a liquid phase raw material, wherein: The solid phase raw materials include: closed perlite, expanded perlite, hollow vitrified microspheres, hydroxyethyl cellulose, and polypropylene fiber; the liquid phase raw materials include: silicone-acrylic emulsion, silane coupling agent, and aerogel slurry. The aerogel slurry has a thermal conductivity of 0.018~0.022, a particle diameter of 15~30 μm, a solid content of 10~15%, and a viscosity of 30000~40000 cp.

[0025] It should be noted that the functions of each component in the solid-phase raw material of this invention are as follows: Closed-cell perlite provides a closed-pore structure, reducing water absorption; expanded perlite, with its low-density properties, can significantly reduce the overall density of the material, while its porous structure can provide adhesion sites for aerogel slurry; hollow vitrified microspheres significantly reduce the thermal conductivity and density of the material through their low thermal conductivity hollow spherical structure; hydroxyethyl cellulose acts as a thickener, water retainer, and suspender, improving workability and promoting filler dispersion; polypropylene fibers enhance the toughness and crack resistance of the material, inhibiting the formation of drying shrinkage cracks.

[0026] The functions of each component in the liquid-phase raw material of this invention: Silicone-acrylic emulsion, as the main organic binder, endows the system with good film-forming properties, flexibility, and weather resistance, and improves adhesion and crack resistance. Silane coupling agent improves the interfacial bonding between inorganic fillers and organic components, enhances dispersibility and interfacial stability, and further improves the overall performance and durability of the material. The aerogel slurry can fully bond with the porous perlite matrix in the solid raw material to form an excellent micro-nano porous thermal insulation network.

[0027] The thermal insulation gel of this application, composed of the above-mentioned raw materials, utilizes the excellent dispersibility of the aerogel slurry to fully bond with the porous perlite matrix in the solid raw materials, forming an excellent micro-nano porous thermal insulation network, which greatly reduces the thermal conductivity of the product. Therefore, the thermal insulation gel product prepared by this invention has the characteristics of low thermal conductivity, low density, high flame retardancy, and high adhesive strength, overcoming the shortcomings of traditional building exterior wall insulation materials that cannot simultaneously achieve excellent mechanical and thermal properties, and providing a new approach for the preparation of advanced thermal insulation gel products.

[0028] Furthermore, the aerogel slurry selected in this application has a thermal conductivity of 0.018~0.022 W / (m•K), a particle diameter of 15~30 μm, a solid content of 10~15%, and a viscosity of 30000~40000 cp. The selection of the aforementioned aerogel slurry parameters has been verified to have a significant impact on the final prepared thermal insulation gel. The technical solution for preparing the thermal insulation gel within the aforementioned aerogel slurry parameter range can effectively balance the mechanical and thermal properties of the thermal insulation gel, resulting in a thermal insulation gel that maintains low thermal conductivity and low density while exhibiting high flame retardancy and high adhesive strength.

[0029] It should be noted that the beneficial effects of the thermal insulation gel in this application can also be summarized as follows: (1) After the aerogel slurry of the present invention is added, its excellent dispersibility allows the aerogel slurry to fully bond with the porous perlite matrix at the interface, forming an excellent micro-nano pore thermal insulation network, which greatly reduces the thermal conductivity of the product, effectively reduces the linear shrinkage rate and density, and alleviates the problem of reduced product bonding strength when the aerogel content is high.

[0030] (2) During the mixing process, the nanoparticles of the aerogel slurry penetrate into the rough pores on the surface of the perlite through capillary action, forming a physical interlocking structure similar to a "mortise and tenon joint" after solidification. This interlocking effect not only restricts the displacement of the perlite particles through mechanical interlocking, but also enhances the interfacial friction resistance due to the high specific surface area of ​​the aerogel nanoframework. In addition, the high porosity of both (aerogel > 90%, expanded perlite > 80%) significantly reduces the density of the composite material, while the nanopores of the aerogel inhibit air convection and work together with the micron-sized pores of the perlite to optimize the thermal insulation performance. This integrated structure-function design not only solves the defects of traditional perlite materials being brittle and prone to pulverization, but also breaks through the bottleneck of poor mechanical properties of single aerogel.

[0031] (3) The thermal insulation gel product with low thermal conductivity prepared by the present invention has the characteristics of low density, low thermal conductivity, high flame retardancy and high bonding strength. It overcomes the defect that traditional building exterior wall insulation materials cannot simultaneously take into account excellent mechanical and thermal performance, and provides a new idea for the preparation of advanced thermal insulation gel products.

[0032] In a preferred embodiment of the present invention, the mass ratio of closed perlite, expanded perlite, hollow vitrified microspheres, hydroxyethyl cellulose, and polypropylene fiber in the solid phase raw material is (10.5~22):(20~43):(2~8):(1~5):(1~4). As a preferred embodiment, the thermal insulation gel prepared from solid raw materials within the above-mentioned mass ratio range has the characteristics of low thermal conductivity, low density, high flame retardancy, and high adhesive strength, while embodiments outside the above range have poorer effects. This is because closed-cell perlite in the solid material can improve gel strength, but adding too much will increase the density of the material, which is not conducive to application; expanded perlite can significantly reduce the density of the material and improve thermal insulation performance, but excessive expanded perlite will lead to shrinkage and decreased strength due to high water absorption; hollow vitrified microspheres have both lightweight and high strength, and can improve performance while ensuring low thermal conductivity, but adding too much will reduce fluidity; hydroxyethyl cellulose is mainly used for thickening and water retention, and insufficient content will lead to bleeding and separation, while excessive content will affect the curing strength; polypropylene fiber can effectively improve toughness and crack resistance, but excessive amount will reduce workability.

[0033] In a preferred embodiment of the present invention, the liquid phase raw material further includes: a wetting agent, a defoamer, and water; Preferably, the wetting agent comprises at least one of sodium dodecyl sulfate, alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and polyethylene glycol ester; Preferably, the defoamer includes at least one of silicone defoamer, polyether defoamer, mineral oil defoamer, and polyether-modified silicone defoamer.

[0034] In a preferred embodiment of the present invention, the mass ratio of water, silicone-acrylic emulsion, silane coupling agent, wetting agent, defoamer and aerogel slurry in the liquid phase raw material is (35~65):(35~65):(2~8):(1~4):(0.5~3.5):(196.5~350). In a preferred embodiment, water in the above-mentioned liquid raw materials determines the gel's fluidity; too much water will reduce strength, while too little water will make application difficult. Silicone-acrylic emulsion provides adhesion and flexibility; insufficient content will reduce the bond strength between the gel and the building material substrate, while excessive content will increase thermal conductivity and density. Wetting agents improve the dispersibility of solid particles, and defoamers reduce air bubbles; both excessive amounts will affect the gel molding quality. Aerogel slurry is the main thermal insulation component; increasing its addition can reduce thermal conductivity but weakens strength and bond strength. Testing shows that the thermal insulation gel prepared from the liquid raw materials within the above-mentioned mass ratio range has advantages such as low thermal conductivity, low density, high flame retardancy, and high bond strength.

[0035] Preferably, the silane coupling agent is silane coupling agent KH550.

[0036] According to one aspect of the present invention, a method for preparing a heat-insulating gel, the method comprising: S1: Mix the solid raw material and the liquid raw material separately to obtain solid material and liquid material; S2: Add the liquid phase material to the solid phase material and stir to mix, thus obtaining a gel-like intermediate; S3: Curing and drying the gel-like intermediate to obtain the heat-insulating gel.

[0037] The present invention provides a method for preparing a thermal insulation gel. The method involves first mixing solid and liquid raw materials separately to obtain a solid material and a liquid material. Then, the liquid material is added to the solid material and stirred to obtain a gel-like intermediate. Finally, the intermediate is cured and dried to obtain the thermal insulation gel. This preparation method has the advantages of simple processing and ease of operation.

[0038] In a preferred embodiment of the present invention, the mass ratio of liquid phase material to solid phase material in S2 is 45.5~65:300~495.5.

[0039] In a preferred embodiment of the present invention, the stirring speed in step S2 is 140-150 rpm and the time is 5-15 min.

[0040] In a preferred embodiment of the present invention, the curing temperature in S3 is 20~30℃, the relative humidity is 40~60%, and the time is 2~3 days.

[0041] In a preferred embodiment of the present invention, the drying in S3 is gradient drying; Preferably, the gradient drying temperature is 40, 80, and 105°C, and the duration of each gradient is 0.5 to 3.5 h.

[0042] As a preferred embodiment, the gradient drying method of this application gradually increases the temperature in stages, so that the internal moisture of the material can be discharged evenly. This can effectively reduce drying stress, avoid surface hardening and cracking, and maintain the integrity of the porous structure, thereby maintaining the thermal insulation performance of the material.

[0043] According to one aspect of the present invention, the above-mentioned thermal insulation gel provided by the present invention can be widely used in the preparation process of thermal insulation building materials.

[0044] The technical solution of the present invention will be further described below with reference to the embodiments.

[0045] Examples 1-5 A method for preparing a heat-insulating gel, the method comprising: (1) Add the weighed solid raw materials to the mixing pot of the mortar mixer, adjust the mixing speed to low speed (140~150 rpm), and continue mixing until the solid mixture has a uniform color and no obvious layering or agglomeration, thus obtaining solid material; Water, silicone-acrylic emulsion, silane coupling agent KH550, wetting agent, and aerogel slurry were added sequentially to a 1 L beaker. After each component was added, the mixture was stirred with a glass rod for 1.5 min. Finally, the defoamer was added, and the mixture was stirred for another 5 min to obtain the liquid phase.

[0046] The aerogel slurry has a thermal conductivity of 0.020, a particle diameter of 20 μm, a solid content of 12.5%, and a viscosity of 36500 cp. The compositions of the solid and liquid raw materials in Examples 1-5 are shown in Table 1. Table 1. Composition of solid and liquid raw materials in Examples 1-5:

[0047] Note: In the table above, "-" indicates the same as in Example 1.

[0048] (2) Pour the well-stirred liquid phase into the mortar mixer and mix it with the solid phase. Continue stirring for 10 minutes until the mixture presents a soft, uniform gel-like form without dry powder particles, thus obtaining a gel product with high water content.

[0049] Example 6 Except for the choice of aerogel slurry, this embodiment is the same as that in Example 1.

[0050] In this embodiment, the aerogel slurry has a thermal conductivity of 0.018, a particle diameter of 30 μm, a solid content of 15%, and a viscosity of 30,000 cp.

[0051] Example 7 Except for the choice of aerogel slurry, this embodiment is the same as that in Example 1.

[0052] In this embodiment, the aerogel slurry has a thermal conductivity of 0.022, a particle diameter of 15 μm, a solid content of 10%, and a viscosity of 40,000 cp.

[0053] Comparative Example 1 This comparative example is the same as Example 1, except that the solid content of the aerogel slurry is 20%.

[0054] The aerogel slurry with a solid content of 20% has a thermal conductivity of 0.018, a particle diameter of 20 μm, and a viscosity of 55000 cp.

[0055] Comparative Example 2 This comparative example is the same as Example 1, except that the solid content of the aerogel slurry is 5%.

[0056] The aerogel slurry with a solid content of 5% has a thermal conductivity of 0.035, a particle diameter of 20 μm, and a viscosity of 25000 cp.

[0057] Comparative Examples 3-6 The comparative examples 3 to 6 of this invention are the same as those in Example 1, except that the raw material components or component contents are different from those in Example 1, as shown in Table 2.

[0058] Table 2. Composition of solid and liquid feedstocks in Comparative Examples 3-6:

[0059] Note: In the table above, "-" indicates the same as in Example 1.

[0060] Comparative Example 7 (Implementation method for preparing thermal insulation gel using aerogel powder) A method for preparing a heat-insulating gel, the method comprising: (1) Add the weighed solid raw materials to the mixing pot of the mortar mixer, adjust the mixing speed to low speed, and continue mixing until the solid mixture has a uniform color and no obvious layering or agglomeration, thus obtaining solid material; Water, silicone-acrylic emulsion, silane coupling agent KH550, wetting agent, and aerogel powder (thermal conductivity of 0.025, particle size of 20 μm, hydrophobic) were added to a 1 L beaker. After each component was added, the mixture was stirred with a glass rod for 1.5 min. Finally, the defoamer was added, and the mixture was stirred for another 5 min to obtain the liquid phase.

[0061] The solid phase material ratio is the same as in Example 1. The liquid phase material ratio, except for water and aerogel powder, is the same as in Example 1. The mass of water added is 295g and the mass of aerogel powder is 36.5g.

[0062] (2) Pour the well-stirred liquid phase into the mortar mixer and mix it with the solid phase. Continue stirring for 10 minutes until the mixture presents a soft, uniform gel-like form without dry powder particles, thus obtaining a gel product with high water content.

[0063] Comparative Examples 8-15 The comparative examples 8-15 of this invention are the same as those of Example 1, except that the parameters of the aerogel slurry used are different from those of Example 1, as shown in Table 3.

[0064] Table 3. Parameter selection for comparative examples 8-15 aerogel slurry:

[0065] Note: The “-” in the table above indicates that it is the same as in Example 1.

[0066] Experimental Example 1 To demonstrate that the thermal insulation gel prepared in this application has better thermal conductivity and adhesive strength, the present invention conducts the following tests, the specific test methods being as follows: (1) Thermal conductivity test: The gel products with high water content prepared in the above examples and comparative examples were uniformly filled into an acrylic circular frame with a thickness of 20 mm and an inner diameter of 130 mm. The product was treated with a scraper to fully fill the mold and keep the surface flat and crack-free. Then, it was slowly demolded to obtain a disc-shaped product. The material was cured at 25℃ and 50% relative humidity for 3 days, and the sample was turned over once during the curing period. After curing, the sample was placed in a forced-air drying oven and the program was set to dry it at 40, 80 and 105℃ for 2 h to remove residual moisture in the product. The thermal conductivity of the product after gradient drying was determined using the plate method.

[0067] (2) Bond strength test: First, a small amount of water was applied to a square cement block base with a side length of 60 mm. The gel product with a high water content was evenly added into a 6 mm thick drawing frame with an inner frame side length of 40 mm. The product was treated with a scraper to fully fill the mold and keep the surface flat and crack-free. Then, it was slowly demolded to obtain a square product. The material was cured at 25℃ and 50% relative humidity for 3 days. After curing, the sample was placed in a forced-air drying oven and the program was set to dry it at 40, 80 and 105℃ for 2 hours to remove residual moisture from the product. The square drawing head with a side length of 40 mm was bonded to the product with epoxy resin. The tensile mode of the universal testing machine was used to apply an upward tensile stress to the drawing head until the product was completely separated from the cement block base. The maximum tensile stress during the highest test period was recorded as the bond strength of the sample.

[0068] (3) Density detection: Since the sample is relatively regularly shaped, the density of the sample is measured by a geometric method. The size of the sample is accurately measured, the volume V is calculated, the mass m is weighed using a balance, and the density is calculated using the formula density ρ = m / V.

[0069] (4) Flame retardant performance testing: The test shall be conducted in accordance with the fire resistance rating test requirements of GB 8624-2012; According to GB 8624-2012 "Classification of Burning Performance of Building Materials and Products": A (non-combustible material): hardly burns; B1 (Flame-retardant material): It is difficult to ignite when exposed to fire and extinguishes immediately after the fire source is removed; B2 (Flammable Material): It is easily ignited by an open flame, but the rate of spread is controllable; The specific test results are shown in Tables 4 and 5.

[0070] Table 4. Detection results of Examples 1-7 and Comparative Examples 1-7 provided in this experimental case:

[0071] As can be seen from Table 4 above, the thermal insulation gels prepared in Examples 1 to 7 of this application all have good thermal conductivity and bonding strength.

[0072] Compared with the heat-insulating gels prepared in Examples 1-7 of this application, the use of aerogel slurry with a solid content of 20% in Comparative Example 1 resulted in excessively high slurry viscosity, uneven dispersion, poor bonding between the aerogel and perlite interface, poor bonding force in the internal structure of the product, a thermal conductivity of 0.061 W / (m•K), and low bonding strength (only 0.31 MPa). At the same time, the flame retardant performance level was only B2. Comparative Example 2 used an aerogel slurry with a solid content of 5%, which resulted in an incomplete aerogel network and a significant decrease in thermal insulation performance. Its thermal conductivity was 0.068 W / (m•K), the bonding strength was only 0.45 MPa, and the flame retardant effect was poor. In Comparative Example 3, the embodiment without hollow vitrified microspheres had insufficient compressive strength, which led to the collapse of the internal pore structure of the material, increased density, and flame retardant performance level of only B2. In Comparative Example 4, the embodiment with a silicone-acrylic emulsion content of only 10g showed a lack of organic binder phase, resulting in a significant decrease in adhesive strength to only 0.22MPa. Comparative Example 5, which does not contain a silane coupling agent, has poor inorganic-organic interface compatibility, uneven dispersion of polypropylene fibers, poor material forming, and reduced bonding strength, which is only 0.29 MPa. In Comparative Example 6, where the aerogel slurry content was only 120g, the insufficient aerogel content resulted in the incomplete formation of the micro-nano porous thermal insulation network, leading to a higher thermal conductivity. Comparative Example 7, which utilizes aerogel powder to prepare thermal insulation gel, has a thermal conductivity as high as 0.075 W / (m•K), a bonding strength of only 0.33 MPa, and a relatively high density. Its performance is significantly worse than that of Examples 1-7 of this application.

[0073] Table 5 shows the detection results of comparative examples 8-15 provided in this experiment:

[0074] The above comparative examples 8 to 15 are comparative examples for examining various parameters of aerogel slurry. Compared with Examples 1 to 7 of this application, comparative examples 8 to 15 are difficult to achieve the technical effect of this application in simultaneously taking into account excellent mechanical and thermal properties, that is, maintaining low thermal conductivity and low density while having high flame retardancy and high bonding strength.

[0075] As shown in Table 5, the thermal conductivity of the aerogel slurry decreases with the increase of aerogel powder content in the slurry. In Comparative Example 8, the thermal conductivity is 0.015 W / (m•K). Due to the high aerogel powder content in the slurry, the mechanical properties after drying are poor, resulting in a significant decrease in the bonding strength of the finished product, which is only 0.35 MPa. In contrast, in Comparative Example 9, the thermal conductivity is higher (0.025 W / (m•K)). Due to the lower aerogel content in the slurry, the thermal insulation performance of the finished product is worse than that of Examples 1-7.

[0076] In Comparative Example 10, the aerogel slurry particles were too small, which easily led to agglomeration and uneven dispersion in the insulating gel, resulting in local thermal bridges in the finished product and an increase in thermal conductivity, which was 0.054 W / (m•K). In Comparative Example 11, the aerogel slurry particles were too large, making it difficult for the particles to effectively combine with the perlite micropores and form a good "micro-nano porous thermal insulation network", which in turn led to an increase in thermal conductivity and a decrease in bonding strength.

[0077] Comparative Example 12, with its low solid content (8%), lacked effective insulating components and had a high water content, resulting in increased density and a significantly higher thermal conductivity after drying. In contrast, Comparative Example 13, with its high solid content (18%), had excessive viscosity, making it difficult to process and disperse. This also affected the structure and performance of the final product, leading to a decrease in strength, with a bonding strength of only 0.38 MPa.

[0078] The slurry in Comparative Example 14, with its excessively low viscosity (25000cp), was over-diluted, lacking sufficient effective components, and prone to sagging during application, resulting in a product with poor thermal conductivity and bonding strength. In contrast, the slurry in Comparative Example 15, with its excessively high viscosity (45000cp), was difficult to disperse, easily introducing air bubbles and causing structural defects, which deteriorated the thermal conductivity.

[0079] Furthermore, the present invention uses field emission scanning electron microscopy to analyze the thermally insulating gel products with low thermal conductivity obtained in Examples 1-3, specifically: Figure 1 This is a macroscopic morphology image of the thermal conductivity test sample of the thermal insulation gel obtained in Example 1 of the present invention; Figure 2 This is a macroscopic morphology image of the bonding strength test sample of the thermal insulation gel obtained in Example 1 of the present invention; Figure 3 This is a scanning electron microscope image of the heat-insulating gel obtained in Example 1 of the present invention; Figure 4 This is a scanning electron microscope image of the heat-insulating gel obtained in Example 2 of the present invention; Figure 5 This is a scanning electron microscope image of the heat-insulating gel obtained in Example 3 of the present invention.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heat-insulating gel, characterized in that, The thermal insulation gel is prepared from two parts: a solid phase raw material and a liquid phase raw material, wherein: The solid raw materials include: closed perlite, expanded perlite, hollow vitrified microspheres, hydroxyethyl cellulose, and polypropylene fiber; The liquid phase raw materials include: silicone-acrylic emulsion, silane coupling agent and aerogel slurry; the aerogel slurry has a thermal conductivity of 0.018~0.022W / (m•K), a particle diameter of 15~30 μm, a solid content of 10~15%, and a viscosity of 30000~40000 cp.

2. The heat-insulating gel according to claim 1, characterized in that, The mass ratio of closed perlite, expanded perlite, hollow vitrified microspheres, hydroxyethyl cellulose, and polypropylene fiber in the solid phase raw material is (10.5~22):(20~43):(2~8):(1~5):(1~4).

3. The heat-insulating gel according to claim 1, characterized in that, The liquid phase raw material also includes: wetting agent, defoamer and water; Preferably, the wetting agent comprises at least one of sodium dodecyl sulfate, alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and polyethylene glycol ester; Preferably, the defoamer includes at least one of silicone defoamer, polyether defoamer, mineral oil defoamer, and polyether-modified silicone defoamer.

4. The heat-insulating gel according to claim 1, characterized in that, In the liquid phase raw material, the mass ratio of water, silicone-acrylic emulsion, silane coupling agent, wetting agent, defoamer, and aerogel slurry is (35~65):(35~65):(2~8):(1~4):(0.5~3.5):(196.5~350). Preferably, the silane coupling agent is silane coupling agent KH550.

5. A method for preparing a heat-insulating gel according to any one of claims 1 to 4, characterized in that, The preparation method includes: S1: Mix the solid raw material and the liquid raw material separately to obtain solid material and liquid material; S2: Add the liquid phase material to the solid phase material and stir to mix, thus obtaining a gel-like intermediate; S3: Curing and drying the gel-like intermediate to obtain the heat-insulating gel.

6. The method for preparing the heat-insulating gel according to claim 5, characterized in that, The mass ratio of liquid phase material to solid phase material in S2 is 45.5~65:300~495.

5.

7. The method for preparing the heat-insulating gel according to claim 5, characterized in that, The stirring speed in S2 is 140~150 rpm, and the time is 5~15 min.

8. The method for preparing the heat-insulating gel according to claim 5, characterized in that, The curing temperature in S3 is 20~30℃, the relative humidity is 40~60%, and the time is 2~3 days.

9. The method for preparing the heat-insulating gel according to claim 5, characterized in that, The drying process in S3 is a gradient drying process. The gradient drying temperature is 40, 80, and 105℃, and the duration of each gradient is 0.5 to 3.5 h.

10. The use of the thermal insulation gel according to any one of claims 1 to 4 in the preparation of thermal insulation building materials.

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