Heat-insulation high-temperature-resistant low-heat-conduction heat preservation pad and preparation method thereof

Abstract

The invention discloses a heat-insulation high-temperature-resistant low-heat-conductivity heat preservation pad and a preparation method thereof, belongs to the technical field of heat preservation and insulation materials, and aims to solve the technical problems that heat insulation, high temperature resistance and mechanical strength of a heat insulation material in the prior art need to be further improved. The heat insulation layer, the heat reflection layer and the outer shell are arranged from bottom to top, the heat insulation layer is formed by roasting glass fiber reinforced porous aerogel, and the heat reflection layer is formed by roasting heat reflection gel. According to the invention, the heat insulation material is coated with the metal protective shell to prepare the heat insulation and high-temperature-resistant low-heat-conduction heat preservation pad, and the heat insulation material forms a reflection and heat insulation dual-blocking heat management system through mutual cooperation of the heat insulation layer and the heat reflection layer; therefore, the composite material has the advantages of ultralow thermal conductivity, high dimensional stability, excellent impact resistance and long-term thermal cycle reliability.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation materials technology, specifically to a thermal insulation pad with low thermal conductivity that is heat-insulating and resistant to high temperatures and its preparation method. Background Technology

[0002] With the rapid development of technologies in fields such as high-temperature equipment, energy industry, aerospace, metallurgical equipment, and new energy vehicles, the heat generated by equipment systems during operation is constantly increasing, and the temperature gradient between the equipment shell and the surrounding structure is increasing day by day, which puts forward higher requirements for thermal insulation materials.

[0003] Currently, thermal insulation materials not only need to have low thermal conductivity to reduce heat transfer, but also need to have thermal stability and dimensional stability for long-term service in high-temperature environments, while maintaining structural integrity and performance reliability under mechanical shock, thermal shock and high-temperature cycling conditions.

[0004] Traditional thermal insulation materials include fiberglass wool, aluminosilicate fiber felt, microporous insulation materials, air aerogel, and ceramic fiber composite materials. Although they can meet the thermal insulation requirements to a certain extent, materials such as fiberglass wool and aluminosilicate wool mainly rely on the gas static layer between fibers to achieve thermal insulation. Due to the large pore size between fibers and the many solid support paths, the thermal conductivity of the gas and the thermal conductivity of the solid skeleton are significantly enhanced after the temperature rises, making it difficult to meet the requirements of low thermal conductivity. In high-temperature environments, their thermal conductivity increases significantly, and the thermal insulation effect decreases drastically.

[0005] Furthermore, traditional microporous insulation materials and most inorganic thermal insulation pads generally exhibit brittle characteristics and poor impact resistance. When subjected to vibration or external impact, they are prone to microcrack propagation and fragmentation, affecting the structural integrity of the material and the stability of subsequent thermal insulation. Moreover, under high-temperature conditions, the proportion of radiative heat in the total heat transfer increases significantly. If the material lacks infrared reflection or scattering capabilities, external radiative heat will quickly penetrate the insulation layer, leading to a decrease in the thermal insulation effect. In other words, most conventional materials have limited performance in radiative heat shielding. Therefore, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a heat-insulating and high-temperature resistant low thermal conductivity insulation pad and its preparation method, which solves the technical problem that the heat insulation, high-temperature resistance and mechanical strength of the heat insulation materials in the prior art need to be further improved.

[0007] The objective of this invention can be achieved through the following technical solution: a heat-insulating and high-temperature resistant low thermal conductivity insulation pad, comprising a heat insulation layer, a heat reflective layer and an outer shell arranged from bottom to top; the heat insulation layer is formed by calcining glass fiber reinforced porous aerogel, and the heat reflective layer is formed by calcining heat reflective gel.

[0008] The preparation method of glass fiber reinforced porous aerogel is as follows: polyethylene glycol, polyacrylic acid, anhydrous ethanol and deionized water are mixed and stirred until the system is dissolved. Tetraethyl orthosilicate, AlCl3·6H2O, LiCl·H2O and siloxane are added to the reaction system to activate the fibers. The temperature of the reaction system is reduced to 10-20℃. Boric acid and propylene oxide are added to the reaction system and stirred and dispersed for 30-50 min to obtain a glass fiber reinforced gel solution. The glass fiber reinforced gel solution is added to a mold, allowed to stand for 24 h, and then post-treated to obtain glass fiber reinforced porous aerogel.

[0009] The preparation method of heat-reflective gel is as follows: polyethylene glycol, polyacrylic acid, anhydrous ethanol and deionized water are mixed and stirred until the system is dissolved. Tetrabutyl orthosilicate, tetrabutyl titanate, zinc oleate and LiCl·H2O are added to the reaction system. The temperature of the reaction system is reduced to 20-30℃. Boric acid and propylene oxide are added to the reaction system and stirred and dispersed for 30-50 min to obtain heat-reflective gel. The heat-reflective gel solution is added to a mold, allowed to stand for 24 h, and then post-treated to obtain heat-reflective gel.

[0010] Furthermore, the ratio of polyethylene glycol, polyacrylic acid, anhydrous ethanol, deionized water, tetraethyl orthosilicate, AlCl3·6H2O, LiCl·H2O, siloxane-activated fibers, boric acid, and propylene oxide is 3g:1g:30mL:10mL:8-10g:2-3g:0.6-0.8g:6-7g:1.1-1.2g:2g. The post-treatment process in the preparation of the glass fiber reinforced porous aerogel includes: after settling, immersing the pre-formed sample in anhydrous ethanol, replacing the ethanol every 8 hours, soaking for 40 hours, aging at room temperature for 4-5 hours, and drying in a supercritical carbon dioxide environment for 6-8 hours to obtain the glass fiber reinforced porous aerogel.

[0011] Furthermore, the ratio of polyethylene glycol, polyacrylic acid, anhydrous ethanol, deionized water, tetraethyl orthosilicate, tetrabutyl titanate, zinc oleate, LiCl·H2O, boric acid, and propylene oxide is 3g:1g:30mL:10mL:7-8g:3-4g:2-3g:1.1-1.4g:1.1-1.2g:2g. The post-treatment process in the preparation of the heat-reflective gel includes: after standing, immersing the pre-formed sample in anhydrous ethanol, replacing the ethanol every 8 hours, soaking for 40 hours, aging at room temperature for 4-5 hours, and drying in a supercritical carbon dioxide environment for 6-8 hours to obtain the heat-reflective gel.

[0012] Furthermore, the calcination operation is as follows: the aerogel sample is placed in a muffle furnace, the muffle furnace is heated to 800°C at a rate of 5-8°C / min, and calcined at this temperature for 130-150min. The muffle furnace is then allowed to cool naturally to room temperature, and the sample is discharged to complete the calcination.

[0013] Furthermore, the siloxane-activated fibers are obtained through the following steps:

[0014] A1. The activated glass fiber is laid flat on a plastic tray, and then the modification solution is sprayed evenly on the glass fiber in 5 times. After post-treatment, the loaded glass fiber is obtained.

[0015] A2. Under an inert gas atmosphere, the loaded glass fiber and propyltrimethoxysilane isocyanate solution are mixed, the temperature of the reaction system is raised to 50-60℃, and the reaction is kept at this temperature for 80-100 min. After post-treatment, siloxane activated fiber is obtained.

[0016] Furthermore, in step A1, the solid-liquid ratio of the activated glass fiber and the modifying liquid is 1:6-7. After each spraying, the glass fiber is placed at room temperature for 50-60 minutes and turned over for 30-60 seconds. The post-treatment includes: after the reaction is complete, the glass fiber is washed with purified water until neutral and then transferred to a drying oven at a temperature of 70-80℃ to dry to constant weight. Small-sized impurities are then removed by sieving through a 20-mesh sieve to obtain the loaded glass fiber.

[0017] Further, in step A2, the ratio of the loaded glass fiber to the propyltrimethoxysilane isocyanate solution is 3g:10mL. The propyltrimethoxysilane isocyanate solution is composed of propyltrimethoxysilane and tetrahydrofuran at a ratio of 1.2-1.3g:10mL. The post-treatment includes: after the reaction is complete, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed three times with tetrahydrofuran, and then transferred to a drying oven at a temperature of 50-60℃ and vacuum dried to constant weight to obtain siloxane activated fiber.

[0018] Furthermore, the modifying liquid is obtained through the following steps:

[0019] B1. Mix hollow glass microspheres and dilute hydrochloric acid, raise the temperature of the reaction system to 70-80℃, ultrasonically disperse for 40-60 min, and then perform post-treatment to obtain activated glass microspheres;

[0020] B2. Mix and stir activated glass microspheres, anhydrous ethanol, tetraethyl orthosilicate, and γ-aminopropyltriethoxysilane. Raise the temperature of the reaction system to 50-60℃, add a catalyst to the reaction system, and keep the reaction at this temperature for 20-30 minutes to obtain the modified solution.

[0021] Further, in step B1, the solid-liquid ratio of the hollow glass microspheres and dilute hydrochloric acid is 1:10-15, and the concentration of the dilute hydrochloric acid is 0.5-0.8 mol / L. The post-treatment includes: after the reaction is complete, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed with purified water until neutral, dried, and the filter cake is transferred to a drying oven at a temperature of 70-80℃ and dried to constant weight to obtain activated glass microspheres; in step B2, the ratio of the activated glass microspheres, anhydrous ethanol, tetraethyl orthosilicate, γ-aminopropyltriethoxysilane, and catalyst is 10g:90mL:2.4-2.8g:1.2-1.6g:10mL, and the catalyst is 2-3 mol / L hydrochloric acid.

[0022] Furthermore, the preparation method of activated glass fiber is as follows: glass fiber and activation solution are mixed, the temperature of the reaction system is raised to 80-90℃, ultrasonically dispersed for 50-60 min, and then post-treated to obtain activated glass fiber.

[0023] Furthermore, the solid-liquid ratio of the glass fiber and the activation solution is 1:5-6, and the activation solution is composed of 4-6 mol / L nitric acid and potassium permanganate at a ratio of 10 mL:1 g. The post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed with purified water until neutral and then dried, the filter cake is transferred to a drying oven at a temperature of 70-80℃ and dried to constant weight to obtain activated glass fiber.

[0024] The present invention also proposes a method for preparing a heat-insulating and high-temperature resistant low thermal conductivity insulation pad, comprising the following steps:

[0025] S1. Apply adhesive to the bottom of the insulation layer, then bond the heat reflective layer to the bottom of the insulation layer, and cure to obtain the insulation material;

[0026] S2. With the heat-reflective layer facing down, cover the outside of the insulation material with a metal shell, and make holes in the metal shell for installation and fixing to obtain the insulation pad.

[0027] Furthermore, the adhesive is composed of 10wt% water glass solution and 10wt% aluminum sulfate aqueous solution in a volume ratio of 3:1. The curing operation includes: applying a pressure of 1-2MPa between the heat insulation layer and the heat reflective layer, and drying in a drying oven at a temperature of 70-80℃ for 8-10 hours to obtain the heat insulation material.

[0028] The present invention has the following beneficial effects:

[0029] 1. This invention prepares a thermal insulation material by bonding an insulation layer and a heat-reflective layer at the interface. The heat-reflective layer reduces radiant heat input, while the insulation layer blocks conductive and gaseous heat. The two layers combined form a dual-blocking thermal management system of reflection and insulation, allowing the material to maintain low heat flux density and high structural integrity even in extreme environments. A metal outer shell is then encased on the outside, with holes for installation and fixing, facilitating the installation and fixation of the insulation pad. Furthermore, the metal outer shell effectively protects the insulation material from damage caused by strong external impacts. Within the insulation material, through the bonding of the insulation layer... The bottom of the thermal layer is constructed with a heat-reflective layer composed of SiO2-TiO2-ZnO composite ceramics. Through the synergy of titanium oxide and zinc oxide components, the material has strong mid- and far-infrared reflection and scattering capabilities, forming a heat reflection at the front end of the insulation layer. This reduces the heat flux of external radiant heat entering the insulation layer and improves the thermal insulation performance of the material. The insulation layer and the heat-reflective layer are bonded together by an inorganic binder of aluminum silicate formed by water glass and aluminum sulfate. This creates a stable inorganic interface bond between the reflective layer and the insulation layer, resulting in excellent thermal expansion matching and preventing delamination due to differences in high-temperature expansion. This ensures the integrity of the heat reflection and insulation structure.

[0030] 2. This invention further involves sequentially acid-washing activation, strong oxidation roughening, and silane and siloxane modification of glass fibers and hollow glass microspheres. This process creates a multi-level interface structure between the fiber / microsphere / matrix, composed of rough morphology and chemical bonding, establishing a continuous three-dimensional load-bearing skeleton and a high-strength interface bonding network. Furthermore, it forms a multi-element modified silicate network with tetraethyl orthosilicate, AlCl3·6H2O, LiCl·H2O, and boric acid. Supercritical drying maintains the nano-level porous structure and extremely high porosity of the aerogel material, effectively extending the solid heat transfer path and suppressing gas-phase heat conduction, significantly reducing the material's equivalent thermal conductivity. The introduction of Al, Li, and B components into the SiO2 skeleton and the use of the porous structure to provide a buffer for volume expansion allow the material to exhibit small overall dimensional changes and stable linear expansion behavior within a temperature range from room temperature to 800℃. This effectively reduces the risk of thermal stress and thermal deformation under high-temperature operating conditions and thermal cycling, significantly improving the material's dimensional stability and safety in use.

[0031] 3. This invention further modifies the glass fibers using a modifying liquid, enabling the hollow glass microspheres to be bonded via siloxanes, thereby increasing the surface roughness of the glass fibers. Propyltrimethoxysilane isocyanate is used to coat the glass fiber surface with a flexible siloxane film. This flexible interface can buffer and absorb stress under external impact or uneven thermal expansion, effectively inhibiting crack initiation and propagation. Simultaneously, the glass fiber skeleton in the multi-level reinforcement structure provides high mechanical support, enabling the porous insulation layer to maintain lightweight while possessing good toughness. When the material is subjected to impact loads, it can disperse stress through various energy dissipation mechanisms such as fiber pull-out, interfacial microcrack propagation, and progressive failure of the porous structure, thus significantly improving the overall fracture toughness and impact resistance. The reinforcing effect of the glass fibers further reduces the dimensional changes caused by thermal expansion under heated conditions, improving the dimensional stability of the insulation material. Detailed Implementation

[0032] 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.

[0033] In this invention, the metal outer shell is composed of a metal alloy with low thermal conductivity, preferably: CUSN8 tin bronze alloy;

[0034] In this invention, the hollow glass microspheres have a diameter of 20-100 μm and are selected from commercially available products from Lingshou County Fanhong Mining Co., Ltd.

[0035] In this invention, the glass fiber is chopped glass fiber with a length of 30-50mm, selected from commercially available products of Jiangsu Libang Environmental Protection Technology Co., Ltd.

[0036] In this invention, the polyethylene glycol is PEG-800, selected from commercially available products of Jining Tangyi Chemical Co., Ltd.

[0037] In this invention, the effective component of polyacrylic acid is 99%, and it is selected from commercially available products from Wuhan Huaxiang Kejie Biotechnology Co., Ltd.

[0038] Example 1

[0039] This embodiment provides a method for preparing a heat insulation layer material, including the following steps:

[0040] Step A1: Preparation of the modification solution

[0041] Hollow glass microspheres and 0.5 mol / L hydrochloric acid were added to a reaction flask at a solid-liquid ratio of 1:10 and mixed. The temperature of the reaction flask was raised to 70°C and ultrasonically dispersed for 40 min. The temperature of the reaction flask was then lowered to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried. The filter cake was transferred to a drying oven at 70°C and dried to constant weight to obtain activated glass microspheres.

[0042] In the reaction, the hollow glass microspheres are mainly composed of silicate glass such as SiO2-Al2O3-Na2O, and their surfaces contain a certain amount of alkaline oxides or amorphous layers. They are then acid-leached with hydrochloric acid and processed using H2O. + With surface Na + Ca 2+ The exchange process dissolves the surface passivation layer and metallic impurities, increases the surface hydroxyl density, and forms a large number of hydroxyl groups on the surface of hollow glass microspheres, thereby improving the chemical reactivity of the microsphere surface and providing sites for subsequent silane coupling reactions.

[0043] Weigh out 100g of activated glass microspheres, 900mL of anhydrous ethanol, 24g of tetraethyl orthosilicate, and 12g of γ-aminopropyltriethoxysilane and add them to a reaction flask. Stir the mixture and raise the temperature of the reaction flask to 50℃. Add 100mL of 2mol / L hydrochloric acid to the reaction flask and keep the mixture warm for 20min to obtain the modified solution.

[0044] In the reaction, a sol-gel modified solution is formed by hydrolyzing and condensing tetraethyl orthosilicate, γ-aminopropyltriethoxysilane, and activated glass microspheres in an acidic ethanol environment.

[0045] Step A2: Preparation of loaded glass fibers

[0046] Mix 4 mol / L nitric acid and potassium permanganate at a ratio of 10 mL: 1 g to obtain an activation solution;

[0047] Glass fiber and activation solution were added to a reaction flask at a solid-liquid ratio of 1:5 and mixed. The temperature of the reaction flask was raised to 80°C and ultrasonically dispersed for 50 min. The temperature of the reaction flask was lowered to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried. The filter cake was transferred to a drying oven at 70°C and dried to constant weight to obtain activated glass fiber.

[0048] In the reaction, nitric acid and potassium permanganate construct an oxidizing activating solution. While etching a micro-nano rough surface on the glass fiber surface, a large number of active sites that can condense with silane are formed on the glass fiber surface, thereby increasing the surface area and reactivity of the activated glass fiber.

[0049] Weigh out 100g of activated glass fiber and spread it evenly on a plastic tray. Then, spray 600mL of modification solution evenly onto the glass fiber in 5 portions. After each spraying, let it stand at room temperature for 50min, turn the glass fiber over for 30s, wash the glass fiber with purified water until it is neutral, and then transfer it to a drying oven at 70℃. Dry it until it reaches constant weight, and then sieve it through a 20-mesh sieve to remove small-diameter impurities to obtain loaded glass fiber.

[0050] In the reaction, by spraying the modification liquid onto the activated glass fiber, the unreacted silanol in the modification liquid further condenses with the hydroxyl groups on the glass fiber surface. At the same time, the polysiloxane network already coated on the surface of the microbeads can also bridge and crosslink with the glass fiber surface and condense with the active reaction sites on the surface of the activated glass fiber. By spraying multiple times and allowing it to stand, it can be ensured that the silane forms a uniform film and penetrates into the micro-rough area of ​​the fiber surface.

[0051] Step A3: Preparation of siloxane-activated fibers

[0052] A solution of propyltrimethoxysilane isocyanate was obtained by mixing propyltrimethoxysilane and tetrahydrofuran at a ratio of 1.2 g: 10 mL.

[0053] Weigh 120g of loaded glass fiber and 400mL of propyltrimethoxysilane isocyanate solution and add them to an argon-protected reaction flask. Stir the mixture and raise the temperature of the reaction flask to 50℃. Keep the reaction temperature at 50℃ for 80min. Then lower the temperature of the reaction flask to room temperature and filter the mixture. Wash the filter cake three times with tetrahydrofuran and transfer it to a drying oven at 50℃. Dry the cake under vacuum until constant weight to obtain siloxane-activated fiber.

[0054] In the reaction, a flexible siloxane coating layer is formed on the glass fiber by condensation of the siloxane bond on the propyltrimethoxysilane molecule with the modified amino group on the supported glass fiber, thus preparing siloxane activated fiber.

[0055] The flexible siloxane coating on the outside of the activated fiber can absorb external forces and thermal stress, act as a buffer, and inhibit crack propagation. Utilizing the reactivity of siloxane, a chemical bridging network is established between the glass fiber and the microspheres, allowing the glass fiber to be firmly embedded in the silicate aerogel skeleton, significantly improving structural integrity. Fiber pull-out, interface slip, and multi-level failure mechanisms are fully utilized, improving the impact resistance and toughness of the insulation layer. The siloxane coating enhances the interfacial stability between the glass fiber and the gel material, and the strong interface makes the skeleton less prone to collapse, reducing the thermal conductivity of the gas and solid phases of the material at high temperatures.

[0056] Step A4: Prepare the insulation layer

[0057] Weigh out 30g of polyethylene glycol, 10g of polyacrylic acid, 300mL of anhydrous ethanol and 100mL of deionized water and add them to the reaction flask. Stir until dissolved. Add 80g of tetraethyl orthosilicate, 20g of AlCl3·6H2O, 6g of LiCl·H2O and 60g of siloxane-activated fiber to the reaction flask. Lower the temperature of the reaction flask to 10℃. Add 11g of boric acid and 20g of propylene oxide to the reaction flask and stir to disperse for 30min to obtain a glass fiber reinforced gel solution.

[0058] The glass fiber reinforced gel solution was added into the mold and allowed to stand for 24 hours. The pre-formed sample was then immersed in anhydrous ethanol, and the anhydrous ethanol was replaced every 8 hours. After immersion for 40 hours, the sample was aged at room temperature for 4 hours and then dried in a supercritical carbon dioxide environment for 6 hours to obtain a glass fiber reinforced porous aerogel with a thickness of 4.8 cm.

[0059] The glass fiber reinforced porous aerogel was placed in a muffle furnace, which was heated to 800°C at a rate of 5°C / min and calcined for 130 minutes. The muffle furnace was then allowed to cool naturally to room temperature before the material was discharged, thus obtaining the insulation layer.

[0060] In the reaction, ethanol and water are used as solvents, and polyethylene glycol and polyacrylic acid are used as organic additives and transient templates. Tetraethyl orthosilicate, AlCl3·6H2O, LiCl·H2O, and siloxane activate the fibers. First, acid-catalyzed hydrolysis is carried out at a low temperature. Then, rapid polycondensation is triggered by propylene oxide consuming acid to increase pH, completing the transformation from sol to gel. The gel is repeatedly replaced by ethanol to reduce the surface tension and inorganic salt / small molecule residues in the pores. Then, supercritical CO2 drying is used to achieve a liquid-gas transition "interfaceless" path above the critical point, avoiding the collapse of the skeleton and pore throat closure caused by capillary pressure. This maximizes the preservation of the nano-micro multi-level pore structure and extremely high porosity, laying the structural foundation for obtaining an ultra-low effective thermal conductivity. The heat insulation layer is prepared by heating and calcining to promote the complete removal of organic matter and densification of the skeleton.

[0061] The hydrolysis products of AlCl3·6H2O condense with Si-OH during the polymerization process to form Al-O-Si bridges; after hydrolysis of boric acid, they condense with Si-OH to construct BO-Si bridges; Li + As a network-modifying ion, it electrostatically coordinates with surrounding non-bridging oxygens, regulating the local structure and gelation kinetics. Subsequent heat treatment of the gel forms an aluminoborosilicate network dominated by SiO2, containing Al-O-Si and BO-Si bonds. Li + In combination with Al-Si, ordered structural coordination is formed, thereby altering the elastic and thermal vibration characteristics of the framework; Al-O-Si and BO-Si bridging is formed and stabilized; the introduction of Al and B increases the crosslinking degree and structural rigidity of the glass network, while suppressing viscous flow and shrinkage at high temperatures; the tunable balance of tri- / tetra-coordination of B helps reduce the average thermal amplitude of the framework; Li+ As a network-modifying ion, it alters the proportion of non-bridging oxygen and the local structural relaxation mechanism, forming locally short-range ordered metastable fragments of "lithium-aluminosilicate-like" structures in Al-containing systems, thus reducing the thermal expansion of the network. The siloxane-activated fiber surface has a hydrolyzable condensable silane layer. During gelation and drying, the Si-OH on the fiber surface undergoes further condensation bonding with the Si-OH / Al-OH / B-OH in the sol, enhancing the interfacial strength while forming a strong coupling interface of "chemical bridging + mechanical interlocking," anchoring the brittle aerogel skeleton onto the continuous fiber network, further improving the dimensional stability of the material.

[0062] Example 2

[0063] This embodiment provides a method for preparing a heat insulation layer material, including the following steps:

[0064] Step A1: Preparation of the modification solution

[0065] Hollow glass microspheres and 0.65 mol / L hydrochloric acid were added to a reaction flask at a solid-liquid ratio of 1:13 and mixed. The temperature of the reaction flask was raised to 75°C and ultrasonically dispersed for 50 min. The temperature of the reaction flask was then lowered to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried. The filter cake was transferred to a drying oven at 75°C and dried to constant weight to obtain activated glass microspheres.

[0066] Weigh out 100g of activated glass microspheres, 900mL of anhydrous ethanol, 26g of tetraethyl orthosilicate, and 14g of γ-aminopropyltriethoxysilane and add them to a reaction flask. Stir the mixture and raise the temperature of the reaction flask to 55℃. Add 100mL of 2.5mol / L hydrochloric acid to the reaction flask and keep the mixture at this temperature for 25min to obtain the modified solution.

[0067] Step A2: Preparation of loaded glass fibers

[0068] Mix 5 mol / L nitric acid and potassium permanganate at a ratio of 10 mL: 1 g to obtain an activation solution;

[0069] Glass fiber and activation solution were added to a reaction flask at a solid-liquid ratio of 1:5.5 and mixed. The temperature of the reaction flask was raised to 85°C and ultrasonically dispersed for 55 min. The temperature of the reaction flask was then lowered to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried. The filter cake was transferred to a drying oven at 75°C and dried to constant weight to obtain activated glass fiber.

[0070] Weigh out 100g of activated glass fiber and spread it evenly on a plastic tray. Then, spray 650mL of modification solution evenly onto the glass fiber in 5 portions. After each spraying, let it stand at room temperature for 55min, turn the glass fiber over for 45s, wash the glass fiber with purified water until it is neutral, and then transfer it to a drying oven at 75℃. Dry it until it reaches constant weight, and then sieve it through a 20-mesh sieve to remove small-diameter impurities to obtain loaded glass fiber.

[0071] Step A3: Preparation of siloxane-activated fibers

[0072] A solution of propyltrimethoxysilane isocyanate was obtained by mixing propyltrimethoxysilane and tetrahydrofuran at a ratio of 1.25 g: 10 mL.

[0073] Weigh 120g of loaded glass fiber and 400mL of propyltrimethoxysilane isocyanate solution and add them to an argon-protected reaction flask. Stir the mixture and raise the temperature of the reaction flask to 55℃. Keep the reaction at this temperature for 90min. Then lower the temperature of the reaction flask to room temperature and filter the mixture. Wash the filter cake three times with tetrahydrofuran and transfer it to a drying oven at 55℃. Dry the cake under vacuum until it reaches a constant weight to obtain siloxane-activated fiber.

[0074] Step A4: Prepare the insulation layer

[0075] Weigh out 30g of polyethylene glycol, 10g of polyacrylic acid, 300mL of anhydrous ethanol and 100mL of deionized water and add them to the reaction flask. Stir until dissolved. Add 90g of tetraethyl orthosilicate, 25g of AlCl3·6H2O, 7g of LiCl·H2O and 65g of siloxane-activated fiber to the reaction flask. Lower the temperature of the reaction flask to 15℃ and add 11.5g of boric acid and 20g of propylene oxide to the reaction flask. Stir and disperse for 40min to obtain a glass fiber reinforced gel solution.

[0076] The glass fiber reinforced gel solution was added into the mold and allowed to stand for 24 hours. The pre-formed sample was then immersed in anhydrous ethanol, and the anhydrous ethanol was replaced every 8 hours. After immersion for 40 hours, the sample was aged at room temperature for 4.5 hours and then dried in a supercritical carbon dioxide environment for 7 hours to obtain a glass fiber reinforced porous aerogel with a thickness of 5 cm.

[0077] The glass fiber reinforced porous aerogel was placed in a muffle furnace, which was heated to 800°C at a rate of 6.5°C / min and calcined for 140 minutes. The muffle furnace was then allowed to cool naturally to room temperature before the material was discharged, thus obtaining the insulation layer.

[0078] Example 3

[0079] This embodiment provides a method for preparing a heat insulation layer material, including the following steps:

[0080] Step A1: Preparation of the modification solution

[0081] Hollow glass microspheres and 0.8 mol / L hydrochloric acid were added to a reaction flask at a solid-liquid ratio of 1:15 and mixed. The temperature of the reaction flask was raised to 80℃ and ultrasonically dispersed for 60 min. The temperature of the reaction flask was then lowered to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried. The filter cake was transferred to a drying oven at 80℃ and dried to constant weight to obtain activated glass microspheres.

[0082] Weigh out 100g of activated glass microspheres, 900mL of anhydrous ethanol, 48g of tetraethyl orthosilicate, and 16g of γ-aminopropyltriethoxysilane and add them to a reaction flask. Stir the mixture and raise the temperature of the reaction flask to 60℃. Add 100mL of 3mol / L hydrochloric acid to the reaction flask and keep the mixture warm for 30min to obtain the modified solution.

[0083] Step A2: Preparation of loaded glass fibers

[0084] Mix 6 mol / L nitric acid and potassium permanganate at a ratio of 10 mL: 1 g to obtain an activation solution;

[0085] Glass fiber and activation solution were added to a reaction flask at a solid-liquid ratio of 1:6 and mixed. The temperature of the reaction flask was raised to 90°C and ultrasonically dispersed for 60 min. The temperature of the reaction flask was then lowered to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried. The filter cake was transferred to a drying oven at 80°C and dried to constant weight to obtain activated glass fiber.

[0086] Weigh out 100g of activated glass fiber and spread it evenly on a plastic tray. Then, spray 700mL of modification solution evenly onto the glass fiber in 5 portions. After each spraying, let it stand at room temperature for 60min, turn the glass fiber over for 60s, wash the glass fiber with purified water until it is neutral, and then transfer it to a drying oven at 80℃. Dry it until it reaches constant weight, and then sieve it through a 20-mesh sieve to remove small-diameter impurities to obtain loaded glass fiber.

[0087] Step A3: Preparation of siloxane-activated fibers

[0088] A solution of propyltrimethoxysilane isocyanate was obtained by mixing propyltrimethoxysilane and tetrahydrofuran at a ratio of 1.3 g: 10 mL.

[0089] Weigh 120g of loaded glass fiber and 400mL of propyltrimethoxysilane isocyanate solution and add them to an argon-protected reaction flask. Stir the mixture and raise the temperature of the reaction flask to 60℃. Keep the temperature at 60℃ for 100min. Then lower the temperature of the reaction flask to room temperature and filter the mixture. Wash the filter cake three times with tetrahydrofuran and transfer it to a drying oven at 60℃. Dry the cake under vacuum until constant weight to obtain siloxane-activated fiber.

[0090] Step A4: Prepare the insulation layer

[0091] Weigh out 30g of polyethylene glycol, 10g of polyacrylic acid, 300mL of anhydrous ethanol and 100mL of deionized water and add them to the reaction flask. Stir until dissolved. Add 100g of tetraethyl orthosilicate, 30g of AlCl3·6H2O, 8g of LiCl·H2O and 70g of siloxane-activated fiber to the reaction flask. Lower the temperature of the reaction flask to 20℃. Add 12g of boric acid and 20g of propylene oxide to the reaction flask and stir to disperse for 50min to obtain a glass fiber reinforced gel solution.

[0092] The glass fiber reinforced gel solution was added into the mold and allowed to stand for 24 hours. The pre-formed sample was then immersed in anhydrous ethanol, and the anhydrous ethanol was replaced every 8 hours. After immersion for 40 hours, the sample was aged at room temperature for 5 hours and then dried in a supercritical carbon dioxide environment for 8 hours to obtain a glass fiber reinforced porous aerogel with a thickness of 5.2 cm.

[0093] The glass fiber reinforced porous aerogel was placed in a muffle furnace, which was heated to 800°C at a rate of 8°C / min and calcined for 150 minutes. The muffle furnace was then allowed to cool naturally to room temperature before the material was discharged, thus obtaining the insulation layer.

[0094] Example 4

[0095] This embodiment provides a method for preparing a heat-reflective layer material, including the following steps:

[0096] Step B1: Preparation of heat-reflective gel

[0097] Weigh out 30g of polyethylene glycol, 10g of polyacrylic acid, 300mL of anhydrous ethanol and 100mL of deionized water and add them to the reaction flask. Stir until dissolved. Add 70g of tetraethyl orthosilicate, 30g of tetrabutyl titanate, 20g of zinc oleate and 11g of LiCl·H2O to the reaction flask. Lower the temperature of the reaction flask to 20℃. Add 11g of boric acid and 20g of propylene oxide to the reaction flask and stir to disperse for 30min to obtain heat-reflective gel.

[0098] The heat-reflective gel solution was added to the mold and allowed to stand for 24 hours. The pre-molded sample was then immersed in anhydrous ethanol, with the anhydrous ethanol being replaced every 8 hours. After immersion for 40 hours, the sample was aged at room temperature for 4 hours and then dried in a supercritical carbon dioxide environment for 6 hours to obtain a heat-reflective gel with a thickness of 0.9 cm.

[0099] Step B2: Prepare the heat-reflective layer

[0100] The heat-reflective gel was placed in a muffle furnace, which was heated to 800°C at a rate of 5°C / min and calcined for 130 minutes. The muffle furnace was then allowed to cool naturally to room temperature before the material was discharged, yielding the heat-reflective layer.

[0101] Example 5

[0102] This embodiment provides a method for preparing a heat-reflective layer material, including the following steps:

[0103] Step B1: Preparation of heat-reflective gel

[0104] Weigh out 30g of polyethylene glycol, 10g of polyacrylic acid, 300mL of anhydrous ethanol and 100mL of deionized water and add them to the reaction flask. Stir until dissolved. Add 75g of tetraethyl orthosilicate, 35g of tetrabutyl titanate, 25g of zinc oleate and 12.5g of LiCl·H2O to the reaction flask. Lower the temperature of the reaction flask to 25℃. Add 11.5g of boric acid and 20g of propylene oxide to the reaction flask and stir to disperse for 40min to obtain heat-reflective gel.

[0105] The heat-reflective gel solution was added to the mold and allowed to stand for 24 hours. The pre-molded sample was then immersed in anhydrous ethanol, with the anhydrous ethanol being replaced every 8 hours. After immersion for 40 hours, the sample was aged at room temperature for 4.5 hours and then dried in a supercritical carbon dioxide environment for 7 hours to obtain a heat-reflective gel with a thickness of 1.0 cm.

[0106] Step B2: Prepare the heat-reflective layer

[0107] The heat-reflective gel was placed in a muffle furnace, which was heated to 800°C at a rate of 6.5°C / min and calcined for 140 minutes. The muffle furnace was then allowed to cool naturally to room temperature before the material was discharged, yielding the heat-reflective layer.

[0108] In the reaction, ethanol and water are used as solvents, and polyethylene glycol and polyacrylic acid are used as organic additives and transient templates. Tetrabutyl orthosilicate, tetrabutyl titanate, zinc oleate, and LiCl·H2O are first subjected to acid-catalyzed hydrolysis at a low temperature. Then, rapid polycondensation is triggered by propylene oxide consuming acid to increase pH, completing the transformation from sol to gel. The gel is replaced with ethanol to reduce the surface tension and inorganic salt / small molecule residues in the pores. Subsequently, supercritical CO2 drying is used to achieve a liquid-gas transition "interface-free" path above the critical point, avoiding framework collapse and pore throat closure caused by capillary pressure. This maximizes the preservation of the nano-micro multi-level pore structure and extremely high porosity, laying the structural foundation for obtaining an ultra-low effective thermal conductivity. The heat-reflective layer is prepared by heating and calcination to promote the complete removal of organic matter and densification of the framework.

[0109] The heat-reflective layer itself has a porous structure and a low solid volume fraction, which reduces the transmission of conductive heat and gaseous heat within the layer. The TiO2 and ZnO phases loaded on it enhance the refractive index of the SiO2 skeleton, causing mid- and far-infrared radiant heat to be strongly reflected and scattered in this layer, reducing the amount of radiative heat flux entering the upper insulation layer from the source. The ceramic structure of the heat-reflective layer provides a front-end "shield" protection for the insulation layer, mitigating the direct effects of external thermal shock and some mechanical shock on the internal porous aerogel skeleton. The insulation layer is also an Al-Li-B multi-component modified SiO2 porous skeleton, and the two have good compatibility and expansion matching in chemical composition and network structure.

[0110] Example 6

[0111] This embodiment provides a method for preparing a heat-reflective layer material, including the following steps:

[0112] Step B1: Preparation of heat-reflective gel

[0113] Weigh out 30g of polyethylene glycol, 10g of polyacrylic acid, 300mL of anhydrous ethanol and 100mL of deionized water and add them to the reaction flask. Stir until dissolved. Add 80g of tetraethyl orthosilicate, 40g of tetrabutyl titanate, 30g of zinc oleate and 14g of LiCl·H2O to the reaction flask. Lower the temperature of the reaction flask to 30℃. Add 12g of boric acid and 20g of propylene oxide to the reaction flask and stir to disperse for 50min to obtain heat-reflective gel.

[0114] The heat-reflective gel solution was added to the mold and allowed to stand for 24 hours. The pre-molded sample was then immersed in anhydrous ethanol, with the anhydrous ethanol being replaced every 8 hours. After immersion for 40 hours, the sample was aged at room temperature for 5 hours and then dried in a supercritical carbon dioxide environment for 8 hours to obtain a heat-reflective gel with a thickness of 1.1 cm.

[0115] Step B2: Prepare the heat-reflective layer

[0116] The heat-reflective gel was placed in a muffle furnace, which was heated to 800°C at a rate of 8°C / min and calcined for 150 minutes. The muffle furnace was then allowed to cool naturally to room temperature before the material was discharged, thus obtaining the heat-reflective layer.

[0117] Example 7

[0118] This embodiment provides a manufacturing process for a heat-insulating and high-temperature-resistant low thermal conductivity insulation pad, including the following steps:

[0119] Step S1: Prepare adhesive

[0120] A binder is obtained by mixing 10 wt% water glass solution and 10 wt% aluminum sulfate aqueous solution at a volume ratio of 3:1.

[0121] Step S2, Adhesion and Fixation

[0122] At 3g / cm 3 The adhesive was applied to the bottom of the heat insulation layer prepared in Example 1, and then the heat reflective layer prepared in Example 4 was bonded to the bottom of the heat insulation layer. A pressure of 1 MPa was applied between the heat insulation layer and the heat reflective layer to make the heat insulation layer and the heat reflective layer fit tightly together. The heat insulation material was obtained by drying in a drying oven at 70°C for 8 hours.

[0123] Step S3: Prepare the thermal insulation pad

[0124] With the heat-reflective layer facing down, a metal shell is wrapped around the outside of the insulation material, and holes for installation and fixing are made in the metal shell to obtain the insulation pad.

[0125] Example 8

[0126] This embodiment provides a manufacturing process for a heat-insulating and high-temperature-resistant low thermal conductivity insulation pad, including the following steps:

[0127] Step S1: Prepare adhesive

[0128] A binder is obtained by mixing 10 wt% water glass solution and 10 wt% aluminum sulfate aqueous solution at a volume ratio of 3:1.

[0129] Step S2, Adhesion and Fixation

[0130] At 3g / cm 3 The adhesive was applied to the bottom of the heat insulation layer prepared in Example 2, and then the heat reflective layer prepared in Example 5 was bonded to the bottom of the heat insulation layer. A pressure of 1.5 MPa was applied between the heat insulation layer and the heat reflective layer to make the heat insulation layer and the heat reflective layer fit tightly together. The mixture was dried in a drying oven at 75°C for 9 hours to obtain the heat insulation material.

[0131] Step S3: Prepare the thermal insulation pad

[0132] With the heat-reflective layer facing down, a metal shell is wrapped around the outside of the insulation material, and holes for installation and fixing are made in the metal shell to obtain the insulation pad.

[0133] Example 9

[0134] This embodiment provides a manufacturing process for a heat-insulating and high-temperature-resistant low thermal conductivity insulation pad, including the following steps:

[0135] Step S1: Prepare adhesive

[0136] A binder is obtained by mixing 10 wt% water glass solution and 10 wt% aluminum sulfate aqueous solution at a volume ratio of 3:1.

[0137] Step S2, Adhesion and Fixation

[0138] At 3g / cm 3 The adhesive was applied to the bottom of the heat insulation layer prepared in Example 3, and then the heat reflective layer prepared in Example 6 was bonded to the bottom of the heat insulation layer. A pressure of 2 MPa was applied between the heat insulation layer and the heat reflective layer to make the heat insulation layer and the heat reflective layer fit tightly together. The heat insulation material was obtained by drying in a drying oven at 80°C for 10 hours.

[0139] Step S3: Prepare the thermal insulation pad

[0140] With the heat-reflective layer facing down, a metal shell is wrapped around the outside of the insulation material, and holes for installation and fixing are made in the metal shell to obtain the insulation pad.

[0141] Comparative Example 1

[0142] The difference between this comparative example and Example 9 is that, in the preparation of the heat insulation layer, activated glass microspheres were not added to the modification solution in step A1.

[0143] Comparative Example 2

[0144] The difference between this comparative example and Example 9 is that, in the preparation of the heat insulation layer, step A3 is omitted, and the loaded glass fiber prepared in step A2 is used instead of the siloxane activated fiber in step A4.

[0145] Comparative Example 3

[0146] The difference between this comparative example and Example 9 is that, in the preparation of the heat insulation layer, LiCl·H2O and boric acid were not added in step A4.

[0147] Comparative Example 4

[0148] The difference between this comparative example and Example 9 is that steps S1-S2 are omitted, and a heat insulation layer of the same thickness as the heat insulation material is used instead.

[0149] Performance testing:

[0150] The thermal conductivity of the insulation material samples prepared in Examples 7-9 and Comparative Examples 1-4 was determined according to the standard GB / T 10297-2015 "Determination of Thermal Conductivity of Non-metallic Solid Materials - Hot Wire Method".

[0151] The coefficients of thermal expansion of the insulation material samples prepared in Examples 7-9 and Comparative Examples 1-4 were determined according to the standard GB / T 34183-2017 "Determination of the coefficient of thermal expansion of insulation products for building equipment and industrial installations" when the temperature rises from room temperature to 800°C.

[0152] The impact strength of the thermal insulation materials prepared in Examples 7-9 and Comparative Examples 1-4 at room temperature was determined using a cantilever beam impact testing machine. The cantilever beam impact test used met the verification requirements of standard JJG 608-2014.

[0153] The thermal insulation materials prepared in Examples 7-9 and Comparative Examples 1-x were heated to 800°C, then allowed to cool naturally to room temperature. This heating and cooling cycle was repeated 20 times. The materials were then processed according to the formula. The impact strength retention rate of the specimen is calculated and denoted as the high-temperature retention rate, where T0 is the impact strength before cyclic heating and cooling, and T... 20 The impact strength after cyclic heating and cooling is shown in Table 1 below.

[0154] Table 1 - Performance Test Data of Samples

[0155] Group Project Thermal conductivity, W / (m·K) coefficient of thermal expansion <![CDATA[Impact strength, kJ·m -2 > High temperature resistance retention rate / % Example 7 0.021 <![CDATA[2.03×10 -6 ]]> 25.5 92.3 Example 8 0.019 <![CDATA[1.98×10 -6 ]]> 25.8 92.6 Example 9 0.020 <![CDATA[2.01×10 -6 ]]> 25.6 92.4 Comparative Example 1 0.025 <![CDATA[2.51×10 -6 ]]> 23.7 91.3 Comparative Example 2 0.023 <![CDATA[2.57×10 -6 ]]> 19.3 86.7 Comparative Example 3 0.024 <![CDATA[2.72×10 -6 ]]> 21.4 79.4 Comparative Example 4 0.031 <![CDATA[2.68×10 -6 ]]> 24.5 87.3

[0156] Data Analysis:

[0157] Comparative analysis of the data in Table 1 above shows that the thermal conductivity of the insulation material prepared by this invention is reduced to 0.019-0.021 W / (m·K), and the coefficient of thermal expansion is reduced to 1.98 × 10⁻⁶. -6 -2.03×10 -6 Its impact resistance reaches 25.5-25.8 kJ / m. 2 After 20 consecutive heating and cooling cycles, the high-temperature resistance retention rate reached 92.3-92.6%, indicating that the present invention prepares thermal insulation materials by using a thermal insulation layer of siloxane-modified glass fiber reinforced porous aerogel and a heat-reflective layer of SiO2-TiO2-ZnO. The heat-reflective layer reduces radiative heat input, while the thermal insulation layer blocks conductive heat and gas heat. The two are superimposed to form a thermal management system with dual blocking of reflection and insulation, achieving synergistic control of thermal conductivity, radiative heat and thermal stress. This results in materials with ultra-low thermal conductivity, high dimensional stability, excellent impact resistance and long-term thermal cycling reliability. By covering the thermal insulation material with a metal shell, a thermally insulating and high-temperature resistant low thermal conductivity pad is prepared, which not only provides buffer protection for the thermal insulation material but also facilitates its installation and fixation.

[0158] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A heat-insulating high-temperature-resistant low-conductive thermal insulation pad, characterized in that, The heat insulation layer is made of glass fiber reinforced porous aerogel after baking, and the heat reflection layer is made of heat reflection gel after baking. The preparation method of the glass fiber reinforced porous aerogel comprises the following steps: mixing and stirring polyethylene glycol, polyacrylic acid, anhydrous ethanol and deionized water until the system is dissolved; adding tetraethyl orthosilicate, AlCl3·6H2O, LiCl·H2O and siloxane activated fiber into the reaction system; reducing the temperature of the reaction system to 10-20℃; adding boric acid and propylene oxide into the reaction system; stirring and dispersing for 30-50 min to obtain a glass fiber reinforced gel solution; pouring the glass fiber reinforced gel solution into a mold; standing for 24 h; and post-processing to obtain the glass fiber reinforced porous aerogel. The preparation method of the heat reflection gel comprises the following steps: mixing and stirring polyethylene glycol, polyacrylic acid, anhydrous ethanol and deionized water until the system is dissolved; adding tetraethyl orthosilicate, tetrabutyl titanate, zinc oleate and LiCl·H2O into the reaction system; reducing the temperature of the reaction system to 20-30℃; adding boric acid and propylene oxide into the reaction system; stirring and dispersing for 30-50 min to obtain the heat reflection gel; pouring the heat reflection gel solution into a mold; standing for 24 h; and post-processing to obtain the heat reflection gel. The polyethylene glycol, polyacrylic acid, anhydrous ethanol, deionized water, tetraethyl orthosilicate, AlCl3·6H2O, LiCl·H2O, siloxane activated fiber, boric acid and propylene oxide are used in a ratio of 3g:1g:30mL:10mL:8-10g:2-3g:0.6-0.8g:6-7g:1.1-1.2g:2g; the post-processing in the preparation process of the glass fiber reinforced porous aerogel comprises the following steps: after standing, immersing the primary molded sample in anhydrous ethanol, replacing the anhydrous ethanol every 8 h, immersing for 40 h, aging for 4-5 h at room temperature, and drying for 6-8 h in a supercritical carbon dioxide environment to obtain the glass fiber reinforced porous aerogel.

2. The low thermal conductive insulation pad according to claim 1, wherein, The polyethylene glycol, polyacrylic acid, anhydrous ethanol, deionized water, tetraethyl orthosilicate, tetrabutyl titanate, zinc oleate, LiCl·H2O, boric acid and propylene oxide are used in a ratio of 3g:1g:30mL:10mL:7-8g:3-4g:2-3g:1.1-1.4g:1.1-1.2g:2g; the post-processing in the preparation process of the heat reflection gel comprises the following steps: after standing, immersing the primary molded sample in anhydrous ethanol, replacing the anhydrous ethanol every 8 h, immersing for 40 h, aging for 4-5 h at room temperature, and drying for 6-8 h in a supercritical carbon dioxide environment to obtain the heat reflection gel.

3. The low thermal conductivity insulation mat of claim 1, wherein, The baking operation comprises the following steps: placing the aerogel sample in a muffle furnace, heating the muffle furnace at a rate of 5-8℃ / min to 800℃, keeping the temperature for 130-150 min, naturally cooling the muffle furnace to room temperature, discharging, and completing the baking.

4. The low thermal conductivity insulation mat of claim 1, wherein, The siloxane activated fiber is obtained by the following steps:

5. The low thermal conductivity insulation mat of claim 1, wherein, A1, spreading the activated glass fiber on a plastic plate, then spraying the modification liquid on the glass fiber for 5 times, post-processing, and obtaining the loaded glass fiber; ​ A2, under inert gas atmosphere, the loaded glass fiber, isocyanic acid propyl trimethoxysilane solution is mixed, the reaction system temperature is raised to 50-60 DEG C, and the reaction is kept for 80-100 min, and then the post-treatment is carried out to obtain the siloxane activated fiber.

6. The low thermal conductivity insulation mat of claim 5, wherein the mat is heat resistant. In step A1, the solid-liquid ratio of the activated glass fiber and the modification liquid is 1:6-7, after each spraying is completed, the glass fiber is placed at room temperature for 50-60 min, and the glass fiber is turned over for 30-60 s, and the post-treatment comprises: after the reaction is completed, the glass fiber is washed to neutral with purified water and then transferred to a drying box with a temperature of 70-80 DEG C, dried to constant weight, and then screened through a 20-mesh sieve to remove small-particle-size impurities to obtain the loaded glass fiber; in step A2, the amount ratio of the loaded glass fiber and the isocyanic acid propyl trimethoxysilane solution is 3 g:10 mL, the isocyanic acid propyl trimethoxysilane solution is composed of isocyanic acid propyl trimethoxysilane and tetrahydrofuran at a ratio of 1.2-1.3 g:10 mL, and the post-treatment comprises: after the reaction is completed, the reaction system temperature is reduced to room temperature, the filter cake is washed with tetrahydrofuran for 3 times, and then transferred to a drying box with a temperature of 50-60 DEG C, and vacuum dried to constant weight to obtain the siloxane activated fiber.

7. The low thermal conductivity insulation mat of claim 5, wherein the mat is heat resistant. The modification liquid is obtained by the following steps: B1, the hollow glass microbeads and dilute hydrochloric acid are mixed, the reaction system temperature is raised to 70-80 DEG C, and ultrasonic dispersion is carried out for 40-60 min, and then the post-treatment is carried out to obtain the activated glass microbeads; B2, the activated glass microbeads, anhydrous ethanol, tetraethyl orthosilicate and gamma-aminopropyl triethoxysilane are mixed and stirred, the reaction system temperature is raised to 50-60 DEG C, a catalyst is added to the reaction system, and the reaction is kept for 20-30 min to obtain the modification liquid.

8. The low thermal conductivity insulation mat of claim 7, wherein the mat is heat resistant. In step B1, the solid-liquid ratio of the hollow glass microbeads and the dilute hydrochloric acid is 1:10-15, the concentration of the dilute hydrochloric acid is 0.5-0.8 mol / L, and the post-treatment comprises: after the reaction is completed, the reaction system temperature is reduced to room temperature, the filter cake is washed to neutral with purified water and then dried, the filter cake is transferred to a drying box with a temperature of 70-80 DEG C, and dried to constant weight to obtain the activated glass microbeads; in step B2, the amount ratio of the activated glass microbeads, anhydrous ethanol, tetraethyl orthosilicate, gamma-aminopropyl triethoxysilane and the catalyst is 10 g:90 mL:2.4-2.8 g:1.2-1.6 g:10 mL, and the catalyst is 2-3 mol / L hydrochloric acid.

9. The low thermal conductivity insulation mat of claim 1, wherein, The preparation method of the activated glass fiber comprises the following steps:

10. The method of claim 1-9, wherein the method is characterized by, S1, a bonding agent is coated on the bottom of the heat insulation layer, and then the heat reflection layer is bonded to the bottom of the heat insulation layer, and cured to obtain the heat insulation material; S2, the heat reflection layer is downward, a metal shell is wrapped outside the heat insulation material, and holes for mounting and fixing are formed on the metal shell to obtain the thermal insulation pad. ​