Thin aerogel film and preparation method thereof

Abstract

The invention discloses a thin aerogel film and a preparation method thereof.The preparation method comprises the following steps that S1, a film material is pretreated, so that the roughness of 50-100 microns is formed on the upper surface of the film material; s2, prime coat glue is sprayed on the upper surface of the membrane material, and a prime coat layer adhering to the upper surface of the membrane material is formed after drying; and S3, the aerogel coating is coated on the bottom coating in a rolling coating mode, and the heat insulation layer adhered to the bottom coating is formed after the aerogel coating is dried. The adhesive force and the anti-falling capacity of the heat insulation layer are effectively enhanced, and the preparation method is simple, easy to operate and suitable for batch production.

Description

Technical Field

[0001] The invention relates to the technical field of thermal insulation materials, and in particular to a thin aerogel film and a preparation method thereof. Background Art

[0002] In all walks of life, carbon capture, carbon storage, and carbon reuse are carried out through industrial optimization, energy transformation, and technological innovation to achieve carbon neutrality, carbon emission reduction, and ultimately "zero emission". In high-energy consumption industries, upgrading energy and adopting more environmentally friendly and efficient thermal insulation or insulation materials have become important ways to achieve carbon emission reduction. Aerogel, an inorganic, environmentally friendly, and highly efficient thermal insulation material, has gradually become a hot topic and is currently the most suitable material for achieving dual carbon.

[0003] Aerogel can be used as a filler in combination with other systems to form a variety of products, such as aerogel felt, aerogel film, aerogel coating, etc. Among them, in the prior art, aerogel films are mostly made by coating wet gel and then supercritical drying. It is difficult for the aerogel film made by this process to maintain the original film shape, and the aerogel layer is easy to crack and the film structure is easily damaged. For example, in Chinese patent CN 105731436B "Continuous ultra-light regular oriented pure graphene aerogel film and preparation method thereof", a straight-line die is used to extrude a graphene gel film, and freeze-drying or supercritical drying is used to form an aerogel film; in Chinese patent CN 113944009A "A method for preparing a PEI / silicon dioxide aerogel film material", a silica aerogel is configured into a spinning precursor solution, and a PEI / silicon dioxide aerogel non-woven film material is prepared by electrospinning double-head blending technology, and then an aerogel film material is formed by hot pressing; in Chinese patent CN 109935757B "A method for preparing a composite lithium-ion battery separator", cotton fibers are coated with a sodium alginate solution, and an aerogel film is obtained by a supercritical carbon dioxide extraction process; Chinese patent CN In 108558430A "A Process for Preparing Low-Radiative Aerogel Film", the wet gel is treated, and a thin film is prepared by spin coating using a single crystal Si wafer as a substrate, and then the aerogel film is obtained by natural cooling after heat treatment.

[0004] The aerogel membranes in these patents are all made of wet gels, which are then prepared into aerogel membranes by supercritical drying, atmospheric pressure drying, freeze drying, or even high temperature heat treatment. The aerogel membranes prepared by these methods are difficult to maintain their original film shape and are prone to structural damage. In addition, the method of drying wet gel membranes into aerogel membranes is also limited by the drying equipment and has high technical requirements. Summary of the invention

[0005] In order to overcome the above-mentioned shortcomings, the purpose of the present invention is to provide a thin aerogel film and a preparation method thereof, which not only preserves the original structure of the aerogel, but also effectively enhances the adhesion and anti-falling ability of the aerogel, and the preparation method is simple and easy to operate, and is suitable for mass production.

[0006] In order to achieve the above object, one of the technical solutions adopted by the present invention is: a method for preparing a thin aerogel film, comprising the following steps: S1. Pre-treat the membrane material so that the upper surface of the membrane material forms a roughness of 50-100 μm; S2, spraying primer glue on the upper surface of the membrane material, and forming a primer layer adhering to the upper surface of the membrane material after drying; S3, applying the aerogel coating on the base coating by roller coating, and forming a heat insulation layer adhered to the base coating after drying.

[0007] The beneficial effects of the preparation method of the present invention are: 1. The roughening treatment of the membrane surface in step S1 can help improve the bonding strength between the subsequent aerogel coating and the membrane surface. Then, by spraying the primer glue in step S2, the strong adhesion of the primer glue can be used to firmly bond the aerogel coating to the membrane surface, thereby inhibiting the shedding of the thermal insulation layer caused by external forces such as collision and friction.

[0008] 2. In step S3, the aerogel coating is directly coated on the primer layer by roller coating, which can ensure the coating uniformity of the aerogel coating and effectively suppress the problem of aerogel cracking after drying; and the film-making steps are simple, and the operability and repeatability are strong.

[0009] Specifically, the aerogel coating is prepared according to the following steps: The aerogel powder is placed in a confined space, and the aerogel powder is blown by jetting, and at the same time, an atomized wetting agent is sprayed into the confined space to completely wet the surface of the aerogel powder; The moistened aerogel powder is mixed with a 1% to 3% aqueous solution of a dispersant to form a viscous and creamy aerogel paste; The aerogel paste is mixed with resin emulsion, water, inorganic filler, defoamer, leveling agent, thickener, mildewproof agent and pH adjuster, and dispersed at a rotation speed of 2500-6000 rpm for 30-120 minutes to obtain an aerogel coating.

[0010] The aerogel powder is sprayed with the wetting agent in a suspended state by jetting, which not only ensures the uniform spraying of the wetting agent, but also reduces the interference of dust in the confined space. At the same time, it can make the hydrophobic aerogel powder easy to mix with the dispersant aqueous solution in the subsequent process, thereby making it easier to prepare the aerogel paste.

[0011] Further, in parts by weight, the aerogel coating includes 30 to 50 parts of aerogel powder, 10 to 80 parts of resin emulsion, 5 to 30 parts of inorganic filler, 50 to 150 parts of water, 5 to 15 parts of wetting agent, 1 to 5 parts of dispersant, 1 to 5 parts of defoaming agent, 1 to 5 parts of leveling agent, 1 to 5 parts of thickener, 0.5 to 5 parts of mildewproofing agent, and 0.5 to 5 parts of pH regulator.

[0012] Furthermore, the wetting agent is a polyether-modified polydimethylsiloxane solution. The dispersant includes at least one of polyethylene glycols, polyvinyl alcohols, polyacrylic acid sodium salts, and polymer anionic dispersants. The inorganic filler includes at least one of glass microspheres, ceramic microspheres, expanded perlite, and expanded vermiculite. The defoamer is an organosilicon defoamer. The leveling agent includes one of acrylic and organosilicon leveling agents. The thickener includes at least one of polyethylene oxide PEO, hydroxyethyl cellulose, organic bentonite, and associative polyurethane.

[0013] Furthermore, in step S3, a tunnel oven is used for drying, and the drying temperature of the tunnel oven changes gradually. In the direction of product movement, the drying temperatures of the tunnel oven are 25°C, 35°C, 50°C, 70°C, 90°C, 110°C, 80°C, 50°C, and 25°C in sequence.

[0014] Furthermore, the substrate coated with the aerogel coating is placed on the conveying track of the tunnel oven, and the forward speed of the conveying track is set to 2-3 m / min, so that the aerogel coating is completely dried through the gradient temperature change and is easy to solidify on the substrate. The gradient drying temperature is conducive to uniform drying of the aerogel, ensuring that the coating is not easy to crack, and enhancing the curing strength of the aerogel coating, thereby inhibiting the peeling of the aerogel coating during subsequent use.

[0015] Furthermore, the dry film thickness of the aerogel coating is 0.1-0.2 mm.

[0016] Specifically, in step S2, the drying temperature is 60-80°C, and the drying time is 10-15 minutes.

[0017] Furthermore, the primer glue is at least one of water-based polyurethane glue, water-based acrylic glue, and water-based chlorinated polyolefin glue.

[0018] Specifically, after step S3, elastic glue is applied to the upper surface of the thermal insulation layer and the lower surface of the film material, and then a release film is applied to form a protective layer. The elastic glue and the release film can protect the surface of the film material and the thermal insulation layer, and the use of the elastic glue can not only ensure close adhesion to the product by its own adhesion, but also has a certain elasticity, can resist deformation damage such as friction and extrusion, and protect the integrity of the thermal insulation layer.

[0019] Furthermore, the dry film thickness of the elastic glue is 0.03~0.05mm.

[0020] Furthermore, the elastic glue is at least one of water-based polypropylene, water-based polyurethane, water-based chlorinated polyolefin, water-based polyvinyl alcohol, water-based vinyl acetate, water-based phenolic, water-based silicone, water-based rubber, and water-based epoxy.

[0021] Specifically, the thickness of the film material is less than 0.1 mm, the thickness of the primer layer is 0.02-0.05 mm, and the thickness of the heat-insulating layer is 0.1-0.2 mm.

[0022] The second technical solution adopted by the present invention is: a thin aerogel film, which is prepared by any of the above-mentioned preparation methods. The thin aerogel film of the present invention has a small volume, a variety of film materials, and is not affected by the gel substrate, drying method and operation process. It can also achieve a good heat insulation effect in a small space, and the heat insulation layer has good strength and is not easy to peel off. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of a thin aerogel membrane according to an embodiment of the present invention.

[0024] In the figure: 1-A surface protection layer; 11-elastic glue; 12-release film; 2-substrate layer; 3-primer layer; 4-heat insulation layer; 5-B surface protection layer. DETAILED DESCRIPTION The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0025] See attached Figure 1 As shown, a thin aerogel film of the present invention comprises an A-surface protective layer 1, a substrate layer 2, a primer layer 3, a heat insulating layer 4, and a B-surface protective layer 5 which are sequentially arranged along the thickness direction.

[0026] Among them, the substrate layer 2 adopts functional film materials, including at least one of thermal conductive film materials, conductive film materials, insulating film materials, sound insulation and noise reduction film materials, reflective film materials, scattering film materials, absorbing film materials, phase change film materials, and protective film materials.

[0027] The base coating 3 uses a water-based adhesive with strong adhesion, which can firmly bond the heat insulation layer to the base layer to prevent the heat insulation layer from falling off due to external forces such as collision and friction. Furthermore, the water-based adhesive is at least one of water-based polyurethane glue, water-based acrylic glue, and water-based chlorinated polyolefin glue.

[0028] The heat insulation layer 4 uses an aerogel heat insulation coating with a thermal conductivity of less than 0.05 W / (m·K).

[0029] The A-side protective layer 1 and the B-side protective layer 5 have the same structure, and both include a release film 12 coated on the surface of the substrate layer 2 or the heat-insulating layer 4 through an elastic glue 11. The elastic glue 11 includes at least one of water-based polypropylene, water-based polyurethane, water-based chlorinated polyolefin, water-based polyvinyl alcohol, water-based vinyl acetate, water-based phenolic, water-based silicone, water-based rubber, and water-based epoxy.

[0030] Specifically, the steps for making the thin aerogel film are as follows: S1. Preparing a substrate layer: pretreating the film material so that the upper surface of the film material has a roughness of 50-100 μm; S2. Prepare the primer layer: spray the primer glue on the upper surface of the membrane material, and dry it at 60-80°C for 10 minutes to form a primer layer adhered to the upper surface of the membrane material; control the dry film thickness to be between 0.02-0.05mm during drying; S3, preparing a heat-insulating layer: applying the aerogel coating on the base coating by roller coating, and forming a heat-insulating layer adhering to the base coating after drying; S4. Prepare protective layer: After applying elastic glue on the lower surface of the membrane material and the upper surface of the thermal insulation layer, dry them at 60-80°C for 10 minutes, and then cover them with release film to form A surface protective layer and B surface protective layer. When drying, control the dry film thickness to be 0.03-0.05mm.

[0031] The roughening treatment of the surface of the membrane material in step S1 can help improve the bonding strength between the subsequent aerogel coating and the membrane material surface. Then, by spraying the primer glue in step S2, the strong adhesion of the primer glue can be used to firmly bond the aerogel coating to the membrane material surface, thereby inhibiting the shedding of the thermal insulation layer caused by external forces such as collision and friction. The aerogel coating is directly coated on the primer layer by roller coating in step S3, which can ensure the coating uniformity of the aerogel coating, thereby effectively inhibiting the problem of aerogel cracking after drying. Finally, the setting of the elastic glue and the release film in step S4 can protect the surface of the membrane material and the thermal insulation layer, and the use of the elastic glue can not only use its own adhesion to ensure close bonding with the product, but also have a certain elasticity, can resist deformation damage such as friction and extrusion, and protect the integrity of the thermal insulation layer.

[0032] In some embodiments, step S3 uses a tunnel oven for drying, and the drying temperature of the tunnel oven varies in a gradient. Specifically, along the direction of product movement, the drying temperatures of the tunnel oven are 25°C, 35°C, 50°C, 70°C, 90°C, 110°C, 80°C, 50°C, and 25°C, respectively. The film material coated with the aerogel coating is placed on the conveying track of the tunnel oven, and the forward speed of the conveying track is set to 2~3m / min, so that the aerogel coating can be cured on the substrate through the gradient temperature change. The gradient drying temperature is conducive to uniform drying of the aerogel, ensuring that the coating is not easy to crack, thereby inhibiting the peeling of the aerogel coating during subsequent use.

[0033] In some embodiments, the thickness of the substrate layer is less than 0.1 mm, the thickness of the primer layer is 0.02-0.05 mm, the thickness of the thermal insulation layer is 0.1-0.2 mm, and the thickness of the elastic glue is 0.03-0.05 mm. The overall thickness of the thin aerogel film is less than 0.5 mm to meet the thermal insulation requirements in a small space.

[0034] In some embodiments, the aerogel coating comprises, by weight, 30 to 50 parts of aerogel powder, 10 to 80 parts of resin emulsion, 5 to 30 parts of inorganic filler, 50 to 150 parts of water, 5 to 15 parts of wetting agent, 1 to 5 parts of dispersant, 1 to 5 parts of defoaming agent, 1 to 5 parts of leveling agent, 1 to 5 parts of thickener, 0.5 to 5 parts of mildewproofing agent, and 0.5 to 5 parts of pH regulator.

[0035] The inorganic filler includes at least one of glass microspheres, ceramic microspheres, expanded perlite, and expanded vermiculite. The wetting agent is a polyether-modified polydimethylsiloxane solution. The dispersant includes at least one of polyethylene glycols, polyvinyl alcohols, sodium polyacrylate, and polymer anionic dispersants. The defoamer is an organosilicon defoamer. The leveling agent includes one of acrylic and organosilicon leveling agents. The thickener includes at least one of polyethylene oxide PEO, hydroxyethyl cellulose, organic bentonite, and associative polyurethane.

[0036] In some embodiments, the aerogel coating is prepared by the following steps: The aerogel powder is placed in a confined space, and the aerogel powder is blown by jetting, and at the same time, an atomized wetting agent is sprayed into the confined space to completely wet the surface of the aerogel powder; The wetted aerogel powder is mixed with a 1-3% concentration of a dispersant aqueous solution to form a viscous and creamy aerogel paste; The aerogel paste is mixed with resin emulsion, water, inorganic filler, defoamer, leveling agent, thickener, mildewproof agent and pH adjuster, and dispersed at a rotation speed of 2500-6000 rpm for 30-120 minutes to obtain an aerogel coating.

[0037] When preparing aerogel coatings, the aerogel powder is sprayed with a wetting agent in a suspended state by jetting, which not only ensures the uniform spraying of the wetting agent, but also reduces the interference of dust in the confined space. At the same time, it can make the hydrophobic aerogel powder easy to mix with the dispersant aqueous solution in the subsequent process, thereby making it easier to prepare the aerogel paste.

[0038] Example 1 Sample 1 was prepared as follows.

[0039] Pre-treating the PET heat-resistant film so that the upper surface of the PET heat-resistant film has a roughness of 80 μm; Spray water-based acrylic glue on the upper surface of the PET heat-resistant film and dry it at 80°C for 10 minutes, controlling the dry film thickness to 0.03mm; The aerogel coating was applied on the water-based acrylic glue by roller coating, and the aerogel coating was dried by gradient temperature to control the dry film thickness to 0.15 mm; Water-based polyurethane glue was applied on the lower surface of the PET heat-resistant film and the aerogel coating respectively, and dried at 80°C for 10 minutes. The dry film thickness was controlled to be 0.04 mm, and then covered with release films respectively.

[0040] Example 2 Sample 2 was prepared as follows.

[0041] Pre-treating the graphite thermal conductive film so that the upper surface of the graphite thermal conductive film has a roughness of 80 μm; Spray water-based acrylic glue on the upper surface of the graphite thermal conductive film and dry it at 80°C for 10 minutes to control the dry film thickness to 0.03mm; The aerogel coating was applied on the water-based acrylic glue by roller coating, and the aerogel coating was dried by gradient temperature to control the dry film thickness to 0.15 mm; Coat the lower surface of the graphite thermal conductive film and the aerogel coating with water-based polyurethane glue respectively, dry them at 80°C for 10 minutes, control the dry film thickness to 0.04mm, and then cover them with release films respectively.

[0042] Example 3 Sample 3 was prepared as follows.

[0043] Pre-treating the graphite thermal conductive film so that the upper surface of the graphite thermal conductive film has a roughness of 80 μm; Spray water-based chlorinated polyolefin glue on the upper surface of the graphite thermal conductive film and dry it at 80°C for 10 minutes to control the dry film thickness to 0.03mm; The aerogel coating was applied on the water-based chlorinated polyolefin glue by roller coating, and the aerogel coating was dried by gradient temperature to control the dry film thickness to be 0.15 mm; Coat the lower surface of the graphite thermal conductive film and the aerogel coating with water-based polyurethane glue respectively, dry them at 80°C for 10 minutes, control the dry film thickness to 0.04mm, and then cover them with release films respectively.

[0044] Comparative Example 1 Comparative Sample 1 was prepared according to the following steps.

[0045] Pre-treating the graphite thermal conductive film so that the upper surface of the graphite thermal conductive film has a roughness of 80 μm; The aerogel coating is coated on the upper surface of the graphite thermal conductive film by roller coating, and the aerogel coating is dried by gradient temperature to control the dry film thickness to be 0.15 mm; Coat the lower surface of the graphite thermal conductive film and the aerogel coating with water-based polyurethane glue respectively, dry them at 80°C for 10 minutes, control the dry film thickness to 0.04mm, and then cover them with release films respectively.

[0046] Comparative Example 2 Comparative Sample 2 was prepared according to the following steps.

[0047] Pre-treating the graphite thermal conductive film so that the upper surface of the graphite thermal conductive film has a roughness of 80 μm; Spray water-based acrylic glue on the upper surface of the graphite thermal conductive film and dry it at 80°C for 10 minutes to control the dry film thickness to 0.03mm; The thermal insulation rock wool is coated on the upper surface of the graphite thermal conductive film by roller coating, and the thickness of the thermal insulation rock wool is controlled to be 1.5 mm; Coat the lower surface of the graphite thermal conductive film and the thermal insulation rock wool with water-based polyurethane glue respectively, dry them at 80°C for 10 minutes, control the dry film thickness to 0.04mm, and then cover them with release films respectively.

[0048] Comparative Example 3 Comparative Sample 3 was prepared according to the following steps.

[0049] Pre-treating the graphite thermal conductive film so that the upper surface of the graphite thermal conductive film has a roughness of 80 μm; Spray water-based acrylic glue on the upper surface of the graphite thermal conductive film and dry it at 80°C for 10 minutes to control the dry film thickness to 0.03mm; The aerogel coating is coated on the water-based acrylic glue by roller coating, and the aerogel coating is dried by gradient temperature to control the dry film thickness to 0.15 mm.

[0050] Comparative Example 4 Comparative Sample 4 was prepared according to the following steps.

[0051] After the graphene oxide aqueous solution with a concentration of 10 mg / mL is continuously and uniformly extruded from a preparation device with a straight-line outlet, it stays in liquid nitrogen for 20 seconds to solidify into a graphene oxide gel film. The graphene oxide gel film is then placed in a -4°C freezer for 5 hours. The frozen graphene oxide gel film is placed in a high-temperature furnace for high-temperature supercritical drying. The drying method is: in an inert gas atmosphere, the temperature is raised to 400°C at 2°C / min, kept warm for 1 hour, then raised to 1300°C at 3°C / min in an inert gas atmosphere, kept warm for 2 hours, then raised to 3000°C at 4°C / min in an inert gas atmosphere, and kept warm for 1.5 hours, and then comparative sample 4 is obtained.

[0052] Experimental example The samples 1-3 and the comparative samples 1-2 were subjected to comparative experiments, and the experimental results are shown in Table 1.

[0053] Table 1 Experimental results

[0054] According to the experimental results in Table 1: The examples 1-3 prepared by the preparation method of the present invention have good thermal insulation performance, and excellent compression resistance, friction resistance, and adhesion performance, and can meet the thermal insulation requirements of small spaces. In addition, the cold surface temperature of examples 2-3 is lower than that of example 1, and the heat dissipation effect of examples 2-3 is better. This is because the film material used in example 1 is a PET heat-resistant film, and the film material used in examples 2 and 3 is a graphite thermal conductive film, and the heat dissipation performance of graphene is better than that of PET material, which can increase the heat transfer speed and thus enhance the heat dissipation efficiency. Comparative sample 1 prepared in comparative example 1 has no primer layer (the aerogel coating is directly coated on the substrate), resulting in poor adhesion of the thermal insulation layer and is very easy to fall off from the substrate.

[0055] Comparative Sample 2 prepared in Comparative Example 2 uses rock wool as the thermal insulation layer, and the thermal insulation effect is obviously poor. In addition, the thickness of the rock wool during preparation is much greater than the thickness of the aerogel coating, resulting in a larger overall thickness of Comparative Sample 2, which is difficult to meet the thermal insulation requirements of a small space.

[0056] Since comparative sample 3 is not provided with a protective layer, during storage or transportation, the thermal insulation layer will be easily worn due to direct contact with objects, resulting in dents on the surface.

[0057] Comparative Sample 4 was prepared by supercritical drying, and the film was brittle, not resistant to pressure, and easily damaged. Since the performance of Comparative Sample 4 was significantly poor, no comparative experiment was performed on it.

[0058] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a thin aerogel film, characterized in that: The steps include: S1. Pre-treat the membrane material so that the upper surface of the membrane material forms a roughness of 50-100 μm; S2, spraying primer glue on the upper surface of the membrane material, and forming a primer layer adhered to the upper surface of the substrate after drying; S3, applying the aerogel coating on the base coating by roller coating, and forming a heat insulation layer adhered to the base coating after drying.

2. The preparation method according to claim 1, characterized in that: The aerogel coating is prepared according to the following steps: The aerogel powder is placed in a confined space, and the aerogel powder is blown by jetting, and at the same time, an atomized wetting agent is sprayed into the confined space to completely wet the surface of the aerogel powder; The wetted aerogel powder is mixed with 1-3% aqueous solution of a dispersant to form a viscous and creamy aerogel paste; The aerogel paste is mixed with resin emulsion, water, inorganic filler, defoamer, leveling agent, thickener, mildewproof agent and pH adjuster, and dispersed at a rotation speed of 2500-6000 rpm for 30-120 minutes to obtain an aerogel coating.

3. The preparation method according to claim 2, characterized in that: In parts by weight, the aerogel coating includes 30 to 50 parts of aerogel powder, 10 to 80 parts of resin emulsion, 5 to 30 parts of inorganic filler, 50 to 150 parts of water, 5 to 15 parts of wetting agent, 1 to 5 parts of dispersant, 1 to 5 parts of defoaming agent, 1 to 5 parts of leveling agent, 1 to 5 parts of thickener, 0.5 to 5 parts of mildewproofing agent, and 0.5 to 5 parts of pH value regulator.

4. The preparation method according to claim 1, characterized in that: In step S3, a tunnel oven is used for drying, and the drying temperature of the tunnel oven changes in a gradient; and along the moving direction of the product, the drying temperatures of the tunnel oven are 25°C, 35°C, 50°C, 70°C, 90°C, 110°C, 80°C, 50°C, and 25°C, respectively.

5. The preparation method according to claim 1, characterized in that: In step S2, the drying temperature is 60-80°C and the drying time is 10-15 minutes.

6. The preparation method according to claim 1, characterized in that: The primer glue is at least one of water-based polyurethane glue, water-based acrylic glue, and water-based chlorinated polyolefin glue.

7. The preparation method according to claim 1, characterized in that: After step S3, elastic glue is coated on the upper surface of the heat insulation layer and the lower surface of the film material respectively, and then a release film is covered thereon to form a protective layer.

8. The preparation method according to claim 7, characterized in that: The elastic glue is at least one of water-based polypropylene, water-based polyurethane, water-based chlorinated polyolefin, water-based polyvinyl alcohol, water-based vinyl acetate, water-based phenolic, water-based silicone, water-based rubber, and water-based epoxy.

9. The preparation method according to claim 1, characterized in that: The thickness of the film material is less than 0.1 mm, the thickness of the primer layer is 0.02-0.05 mm, and the thickness of the heat insulation layer is 0.1-0.2 mm.

10. A thin aerogel film, characterized in that: The method is prepared by any one of claims 1 to 9.

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