A space-grade vacuum insulation panel and a method of making the same

Abstract

This invention relates to a space-grade vacuum insulation panel and its preparation method, belonging to the field of materials technology. It involves selecting specific components and proportions of various organosilanes and mixing them, then drying them at atmospheric pressure to obtain an aerogel core material. The specific surface area of ​​the fiber-reinforced aerogel composite core material is effectively controlled to reach 280–600 m². 2 A micro-nanoporous aerogel core material with a pore size ranging from 30 to 500 nm was obtained, and subsequently used to fabricate a long-life vacuum insulation panel. This atmospheric pressure drying method eliminates the need for chemical modification and low-surface-tension solvent replacement of the aerogel surface. The micro-nanoporous aerogel structure can be directly obtained through high-temperature heating, which facilitates the removal of gas from the aerogel pores during the vacuuming process of the vacuum insulation panel. This reduces the impact of residual gas on the lifespan of the vacuum insulation panel and solves the existing problem of incompatibility between thermal insulation performance and long lifespan in vacuum insulation panels.

Description

Technical Field

[0001] This invention relates to a space-grade vacuum insulation panel and its preparation method, belonging to the field of materials technology. Background Technology

[0002] Vacuum insulation panels (VIPs) are mainly composed of a core material, a barrier membrane, and a getter. Based on the principle of vacuum insulation, the internal core material is evacuated, and then directly heat-sealed by the external surface membrane to form a highly efficient thermal insulation material. Because the internal vacuum environment prevents heat transfer caused by air convection, VIPs have a low thermal conductivity, as low as 3–4 mW / (m·K), about 10 times lower than ordinary insulation materials. They are widely used in construction, aerospace, transportation, and household appliances. Space applications require VIP panels to have a service life of 12 years. Given the high-quality and reliability requirements of spacecraft, ensuring the long-term service life of VIPs is one of the most critical issues, necessitating the development of a new type of VIP material that maintains a low thermal conductivity over a long period.

[0003] The lifespan of a VIP (insulation material) is affected by various factors. Besides the inherent component factors influencing VIP performance, it is also affected by the operating environment and conditions, primarily temperature, humidity, and environmental pressure. Due to prolonged use, gases and water vapor can seep into the VIP through the barrier membrane and seals, and gases can be released into the VIP through the barrier membrane and core material, both causing an increase in internal pressure and thus affecting its lifespan. The actual lifespan of a VIP refers to the number of years during which its thermal conductivity meets the critical value for insulation materials in its operating environment. One of the most important factors in assessing the lifespan of a VIP is the gas pressure of the core material. Higher gas pressure results in a shorter VIP lifespan.

[0004] Silica aerogel possesses a continuous three-dimensional nanoporous structure and a room-temperature thermal conductivity as low as 0.013 W / (m·K), making it the solid material with the lowest thermal conductivity currently available. Fiber-reinforced aerogel materials achieve structural strength through long fiber reinforcement and toughening. Using aerogel as a core material can reduce the thermal conductivity of existing vacuum insulation panels. The porous adsorption properties of aerogel can adsorb water vapor and gas pressure permeating from the membrane, thereby maintaining the low gas pressure and low thermal conductivity of the vacuum insulation panel, resulting in a longer service life. However, existing aerogel materials have a high specific surface area (800–1000 m²). 2 The small nanopore size ( / g) results in poor degassing performance of vacuum insulation panels, leading to the accumulation of residual gas within them. Given the high thermal conductivity of vacuum insulation panels, the slow release of this residual gas causes an increase in internal pressure, further increasing the thermal conductivity and reducing the lifespan of the panel.

[0005] Furthermore, existing insulation boards using fumed silica and silica aerogel as core materials have problems with excessively large or small pore sizes, failing to meet actual application requirements. Summary of the Invention

[0006] The technical problem solved by this invention is to provide a space-grade vacuum insulation panel and its preparation method, which overcomes the shortcomings of existing vacuum insulation panels, such as short lifespan of glass wool core material, poor strength of fumed silica core material, and high initial thermal conductivity. The prepared aerogel composite core material has the characteristics of high strength and micro-nano aerogel pore structure, thereby enabling the vacuum insulation panel to have a low initial thermal conductivity and long service life, which can meet the application requirements of the deep space exploration field.

[0007] The above-mentioned objectives of the present invention are mainly achieved through the following technical solutions:

[0008] A method for preparing a space-grade vacuum insulation panel, comprising:

[0009] A silica sol is obtained by mixing a first silicone grease, a second silicone grease, a catalyst, and a solvent; the mass ratio of the first silicone grease, the second silicone grease, the catalyst, and the solvent is 1:2-6:2-6:10-40; the first silicone grease is one or a combination of tetraethyl orthosilicate, dimethyldiethoxysilane, or dimethyldimethoxysilane; and the second silicone grease is one or a combination of methyltrimethoxysilane, ethyltrimethoxysilane, or methyltrimethoxysilane.

[0010] The silica sol is impregnated into the fiber reinforcement to obtain a silica gel composite material;

[0011] The silica gel composite material is subjected to gel aging by heating;

[0012] The aged silica gel composite material was subjected to high-temperature heating and drying to obtain an aerogel core material.

[0013] The aerogel core material is inserted into a barrier membrane, vacuumed, and then heated and sealed to obtain a vacuum insulation board.

[0014] In the above-mentioned method for preparing a space-grade vacuum insulation panel, the catalyst is one or a combination of concentrated ammonia, sodium hydroxide, or potassium hydroxide.

[0015] In the above-mentioned method for preparing a space-grade vacuum insulation panel, the solvent is one or a combination of methanol, ethanol, or isopropanol.

[0016] In the above-mentioned method for preparing a space-grade vacuum insulation panel, the fiber reinforcement is one or a combination of quartz fiber, high-silica fiber, aluminosilicate fiber, glass fiber, alumina fiber, zirconium oxide fiber, boron nitride fiber, basalt fiber, or mullite fiber; the density of the fiber reinforcement is 0.03–0.15 g / cm³. 3 .

[0017] In the above-mentioned method for preparing a space-grade vacuum insulation panel, the silica gel composite material is placed in an oven and aged by heating at a temperature of 80-100°C for 24-72 hours.

[0018] In the above-mentioned method for preparing a space-grade vacuum insulation panel, the silicone gel composite material after gel aging is placed in an oven for high-temperature heating and drying. The heating conditions are 80℃~90℃ for 2~10 hours, 100℃~110℃ for 2~10 hours, and 120℃~130℃ for 2~10 hours.

[0019] In the above-mentioned method for preparing a space-grade vacuum insulation panel, the aerogel core material is inserted into a barrier membrane, vacuumed, and then heated and sealed. The vacuum degree inside the insulation panel is 0.01 Pa to 10 Pa.

[0020] In the above-mentioned method for preparing a space-grade vacuum insulation panel, the barrier film is made of a material with a thickness of 30 μm to 60 μm.

[0021] In the above-mentioned method for preparing a space-grade vacuum insulation panel, the specific surface area of ​​the core material aerogel is 280–600 m². 2 / g, with pore sizes ranging from 30 to 500 nm (nanometer to micrometer).

[0022] A space-grade vacuum insulation panel includes a silica gel composite material and a barrier film wrapped around the outer surface of the silica gel composite material. The silica gel composite material comprises silica aerogel and inorganic fibers. The silica aerogel has a micro / nano hierarchical porous structure with a specific surface area of ​​280–600 m². 2 / g, with a pore size distribution of 30–500 nm; the bulk density of the inorganic fiber material is 0.01 g / cm³. 3 ~0.90g / cm 3 .

[0023] In the aforementioned space-grade vacuum insulation panel, the inorganic fiber material is one or a combination of quartz fiber, high-silica fiber, aluminum silicate fiber, glass fiber, alumina fiber, zirconium oxide fiber, boron nitride fiber, basalt fiber, or mullite fiber.

[0024] In the aforementioned space-grade vacuum insulation panel, the silica aerogel is prepared from a first silicone grease, a second silicone grease, a catalyst, and a solvent. The mass ratio of the first silicone grease, the second silicone grease, the catalyst, and the solvent is 1:2-6:2-6:10-40. The first silicone grease is one or a combination of tetraethyl orthosilicate, dimethyldiethoxysilane, or dimethyldimethoxysilane. The second silicone grease is one or a combination of methyltrimethoxysilane, ethyltrimethoxysilane, or methyltrimethoxysilane.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] (1) This invention provides a space-grade long-life vacuum insulation panel and its preparation method. A variety of organosilanes with specific components and proportions are mixed and used, and an aerogel core material is obtained by atmospheric pressure drying. The internal specific surface area of ​​the fiber-reinforced aerogel composite core material is effectively controlled to 280–600 m². 2 A micro-nanoporous aerogel core material with a pore size ranging from 30 to 500 nm was obtained, and then used to fabricate a long-life vacuum insulation panel. This atmospheric pressure drying method eliminates the need for chemical modification and low-surface-tension solvent replacement of the aerogel surface. The micro-nanoporous aerogel structure can be directly obtained using high-temperature heating, which facilitates the removal of gas from the aerogel pores during the vacuuming process of the vacuum insulation panel. This reduces the impact of residual gas on the lifespan of the vacuum insulation panel and solves the problem of the incompatibility between thermal insulation performance and long lifespan in existing vacuum insulation panels.

[0027] (2) This invention provides a space-grade long-life vacuum insulation panel and its preparation method, overcoming the shortcomings of existing vacuum insulation panels with short lifespan of glass wool core material, poor strength of fumed silica core material, and high initial thermal conductivity; the prepared aerogel composite core material has the characteristics of high strength and micro-nano aerogel pore structure; the vacuum insulation panel has a low initial thermal conductivity and long service life, which can meet the application requirements of deep space exploration, and the prepared aerogel material has a micro-nano pore structure, the preparation method is simple, no supercritical drying equipment is required, no solvent modification process is required, and the preparation cycle is short. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the vacuum insulation board prepared in Example 1 of the present invention. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments:

[0030] This invention provides a method for preparing a space-grade vacuum insulation panel, comprising the following steps:

[0031] 1. A silica sol is obtained by mixing a first silicone grease, a second silicone grease, a catalyst, and a solvent;

[0032] In one optional embodiment, the mass ratio of the first silicone grease, the second silicone grease, the catalyst, and the solvent is 1:2 to 6:2 to 6:10 to 40.

[0033] In one optional embodiment, the first organosilicon ester is one or a combination of tetraethyl orthosilicate, dimethyldiethoxysilane, or dimethyldimethoxysilane, and the second organosilicon ester is one or a combination of methyltrimethoxysilane, ethyltrimethoxysilane, or methyltrimethoxysilane.

[0034] In one optional embodiment, the catalyst is one or a combination of concentrated ammonia, sodium hydroxide, or potassium hydroxide.

[0035] In one optional embodiment, the solvent is one or a combination of methanol, ethanol, or isopropanol.

[0036] II. Silica sol is impregnated into fiber reinforcement to obtain silica gel composite material;

[0037] In one optional embodiment, the fiber reinforcement is one or a combination of quartz fiber, high silica fiber, aluminosilicate fiber, glass fiber, alumina fiber, zirconium oxide fiber, boron nitride fiber, basalt fiber or mullite fiber.

[0038] In one optional embodiment, the density of the fiber reinforcement is 0.03–0.15 g / cm³. 3 .

[0039] 3. Place the silicone gel composite material in an oven and age it by heating; the heating temperature is 80-100℃ and the time is 24-72h.

[0040] 4. Place the aged silicone gel composite material into an oven for high-temperature heating and drying to obtain the aerogel core material; the heating conditions are 80℃~90℃ for 2~10 hours, 100℃~110℃ for 2~10 hours, and 120℃~130℃ for 2~10 hours.

[0041] 5. The aerogel core material is inserted into the barrier membrane, vacuumed, and then heated and sealed to obtain a vacuum insulation board with a vacuum degree of 0.01 Pa to 10 Pa.

[0042] In one optional embodiment, the material of the barrier film is a material with a thickness of 30μm to 60μm.

[0043] This invention provides a space-grade vacuum insulation panel, comprising a silica aerogel composite material and a barrier film wrapped around the outer surface of the silica aerogel composite material. The silica aerogel composite material includes silica aerogel and inorganic fiber materials. The silica aerogel has a micro-nano hierarchical porous structure with a specific surface area of ​​280–600 m². 2 / g, with a pore size distribution of 30–500 nm; the bulk density of the inorganic fiber material is 0.01 g / cm³. 3 ~0.90g / cm 3 .

[0044] In one optional embodiment, the inorganic fiber material is one or a combination of quartz fiber, high silica fiber, aluminosilicate fiber, glass fiber, alumina fiber, zirconium oxide fiber, boron nitride fiber, basalt fiber or mullite fiber.

[0045] In one optional embodiment, the silicone aerogel is prepared from a first silicone grease, a second silicone grease, a catalyst, and a solvent, wherein the mass ratio of the first silicone grease, the second silicone grease, the catalyst, and the solvent is 1:2 to 6:2 to 6:10 to 40; the first silicone grease is one or a combination of tetraethyl orthosilicate, dimethyldiethoxysilane, or dimethyldimethoxysilane, and the second silicone grease is one or a combination of methyltrimethoxysilane, ethyltrimethoxysilane, or methyltrimethoxysilane.

[0046] Example 1

[0047] Dimethyldiethoxysilane, methyltrimethoxysilane, 25% concentrated ammonia, and ethanol were mixed in a mass ratio of 1:4:3:20 and stirred thoroughly. Glass fiber reinforcement was then impregnated into the silica sol and placed in a sealed container. The mixture was heated in an oven at 80°C for 48 hours to form a wet gel structure. The gel was then placed in an oven and subjected to a gradient heating process: 80°C for 2 hours, 100°C for 3 hours, and 120°C for 3 hours to remove the solvent from the sol, thus preparing the aerogel composite core material for space vacuum insulation panels.

[0048] An aerogel core material was embedded within an aluminum foil barrier membrane, and a vacuum was applied to 1 Pa. After heat sealing, a vacuum insulation panel was obtained. The initial thermal conductivity at room temperature of the vacuum insulation panel was 2.3 mW (m·K). The average pore size of the vacuum insulation panel was 200 nm, and its specific surface area was 400 m². 2 / g.

[0049] like Figure 1 The diagram shown is a schematic diagram of the structure of the vacuum insulation board prepared in Embodiment 1 of the present invention.

[0050] Example 2

[0051] Dimethyldiethoxysilane, methyltrimethoxysilane, 25% concentrated ammonia, and ethanol were mixed in a mass ratio of 1:2:3:40 and stirred thoroughly. Glass fiber reinforcement was then impregnated into the silica sol and placed in a sealed container. The mixture was heated in an oven at 80°C for 48 hours to form a wet gel structure. The gel was then placed in an oven and subjected to a gradient heating process: 80°C for 4 hours, 100°C for 4 hours, and 120°C for 4 hours, to remove the solvent from the sol, thus preparing an aerogel composite core material for space vacuum insulation panels.

[0052] Aerogel core material was embedded in an aluminum foil barrier membrane, evacuated to 1 Pa, and heat-sealed to obtain a vacuum insulation panel. The initial thermal conductivity at room temperature of the vacuum insulation panel was 2.3 mW (m·K). The average pore size of the vacuum insulation panel was 320 nm, and the specific surface area was 500 m². 2 / g.

[0053] The above description is only the best specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

[0054] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for preparing a space-grade vacuum insulation panel, characterized in that, include: A silica sol is obtained by mixing a first silicone grease, a second silicone grease, a catalyst, and a solvent; the mass ratio of the first silicone grease, the second silicone grease, the catalyst, and the solvent is 1:2~6:2~6:10~40; the first silicone grease is one or a combination of tetraethyl orthosilicate, dimethyldiethoxysilane, or dimethyldimethoxysilane; and the second silicone grease is one or a combination of methyltrimethoxysilane, ethyltrimethoxysilane, or methyltrimethoxysilane. The silica sol is impregnated into the fiber reinforcement to obtain a silica gel composite material; The silica gel composite material is subjected to gel aging by heating; The aged silica gel composite material was subjected to high-temperature heating and drying to obtain an aerogel core material. The aerogel core material is inserted into a barrier membrane, vacuumed, and then heated and sealed to obtain a vacuum insulation board. The aged silica gel composite material was placed in an oven for high-temperature drying. The heating conditions were 80ºC~90ºC for 2~10 hours, 100ºC~110ºC for 2~10 hours, and 120ºC~130ºC for 2~10 hours. The specific surface area of ​​the aerogel core material is 280~600 m². 2 / g, with a pore size of 30~500nm.

2. The method for preparing a space-grade vacuum insulation panel according to claim 1, characterized in that, The catalyst is one or a combination of concentrated ammonia, sodium hydroxide, or potassium hydroxide.

3. The method for preparing a space-grade vacuum insulation panel according to claim 1, characterized in that, The solvent is one or a combination of methanol, ethanol or isopropanol.

4. The method for preparing a space-grade vacuum insulation panel according to claim 1, characterized in that, The fiber reinforcement is one or a combination of quartz fiber, high silica fiber, aluminosilicate fiber, glass fiber, alumina fiber, zirconium oxide fiber, boron nitride fiber, basalt fiber or mullite fiber. The density of the fiber reinforcement is 0.03~0.15 g / cm³. 3 .

5. The method for preparing a space-grade vacuum insulation panel according to claim 1, characterized in that, The silica gel composite material is placed in an oven and aged by heating at a temperature of 80~100ºC for 24h~72h.

6. The method for preparing a space-grade vacuum insulation panel according to claim 1, characterized in that, The aerogel core material is inserted into the barrier membrane, vacuumed, and then heated and sealed. The vacuum degree inside the insulation board is 0.01 Pa to 10 Pa.

7. The method for preparing a space-grade vacuum insulation panel according to claim 1, characterized in that, The barrier membrane is made of a material with a thickness of 30μm to 60μm.

8. A space-grade vacuum insulation panel, characterized in that, The preparation method described in claim 1 yields a silica gel composite material and a barrier film coating the outer surface of the silica gel composite material. The silica gel composite material comprises silica aerogel and inorganic fibers. The silica aerogel has a micro / nano hierarchical porous structure with a specific surface area of ​​280–600 m². 2 / g, with a pore size distribution of 30~500nm; the bulk density of the inorganic fiber material is 0.01g / cm³. 3 ~0.90g / cm 3 .

9. The space-grade vacuum insulation panel according to claim 8, characterized in that, The inorganic fiber material is one or a combination of quartz fiber, high silica fiber, aluminum silicate fiber, glass fiber, alumina fiber, zirconium oxide fiber, boron nitride fiber, basalt fiber or mullite fiber.

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