A low-cost, low-density high-temperature resistant thermal insulation material and its preparation method

Abstract

This invention relates to the field of thermal insulation materials technology, and discloses a low-cost, low-density high-temperature resistant thermal insulation material and its preparation method, including the following steps: Step 1, stirring and mixing a high-temperature resistant adhesive, adding a pore-forming agent and stirring and mixing, then adding a thickener and stirring and mixing, and drying to obtain a preliminary thermal insulation material body; Step 2, calcining the preliminary thermal insulation material body to create pores, and cooling to obtain the high-temperature resistant thermal insulation material; In this invention, commercially available high-temperature resistant adhesive is used as raw material, and after mixing with a pore-forming agent and a thickener, it is directly calcined to create pores. Through a simple preparation method, a large number of uniform bubbles are prepared in the adhesive body. These air or materials with low thermal conductivity have significant thermal resistance to heat conduction and have a significant coating thickness, thereby achieving excellent thermal insulation effect.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation materials technology, specifically to a low-cost, low-density, high-temperature resistant thermal insulation material and its preparation method. Background Technology

[0002] With the development of science and technology, high-temperature industries are becoming increasingly common, such as blast furnaces. These industries not only need to reduce internal heat loss and conserve energy, but also ensure a safe working environment for on-site workers. Currently, most of these industries lack insulation measures, leading to energy waste. Furthermore, the long-term exposure to high temperatures poses health risks to workers.

[0003] The insulation layer of a safe requires a low-density, high-temperature resistant insulation material. On one hand, this necessitates reducing the safe's weight (i.e., lower density) to save on transportation costs. On the other hand, it requires excellent insulation performance, as the internal temperature of the safe cannot exceed 180°C. Ideally, it should be cost-effective for large-scale application. The current challenge is that high material density results in poor insulation performance, and the increased thickness leads to higher costs.

[0004] During flight, aerospace vehicles are heated by the engine and aerodynamically heated by the skin, causing the engine compartment temperature to rise rapidly. The aircraft houses numerous instruments and equipment, most of which operate normally below 125°C. Excessive temperatures can malfunction these components, necessitating insulation to prevent heat transfer from the outside. Furthermore, the long hours of continuous engine operation, the small space and large temperature gradient within the engine compartment, the intense mechanical vibrations generated by the engine during normal operation, and the significant advantages of low-density aircraft for extended flight range and increased payload all place stringent demands on the performance of thermal insulation materials.

[0005] CN103848641A discloses an artificial stone with irregular pores and its preparation method. The artificial stone is made from components containing cementitious materials, pore-forming agents, and thickeners according to the following method: preparing a slurry; pouring the prepared slurry into a mold and vibrating it on a vibrating table. Compared with natural stone, this invention's artificial stone with irregular pores is inexpensive, offers diverse effects, is environmentally friendly and radiation-free, has lower density, superior thermal insulation, sound insulation, and fire resistance, and also possesses excellent mechanical properties. It exhibits strong durability and color stability under various harsh climatic environments, making it an ideal decorative material.

[0006] CN101096273A discloses a blocky low-density gel thermal insulation composite material. It utilizes high-polymer polyacrylic acid as a porous nano-silica reinforcing framework, giving the silica gel and its composite material certain elasticity and shrinkage, effectively suppressing crack generation during gel preparation and supercritical drying. A sealing slurry composed of powders such as alumina, titanium dioxide, silicon carbide, hollow glass microspheres, or iron oxide, along with water glass, organosilicon resin, or silica sol, is used to encapsulate the surface of the large silica aerogel. The encapsulated aerogel composite material, after calcination at 650–700℃, can be used at a maximum temperature of 1000℃.

[0007] However, the preparation process of the above materials is complex and the cost is relatively high. Summary of the Invention

[0008] To address the problems of poor thermal insulation performance, high thickness, and high density in existing thermal insulation materials, this invention provides a method for preparing a high-temperature resistant thermal insulation material. By compounding and creating pores in a high-temperature resistant adhesive, a low-density, low-cost thermal insulation material can be obtained. This material has excellent mechanical properties and thermal insulation performance and can be used in boilers, safe insulation layers, and aerospace fields.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A method for preparing a low-cost, low-density, high-temperature resistant thermal insulation material includes the following steps:

[0011] Step 1: Stir and mix the high-temperature resistant adhesive, add the pore-forming agent and stir and mix, then add the thickener and stir and mix, and dry to obtain the preliminary body of the heat insulation material;

[0012] Step 2: The heat insulation material is pre-calcined to create holes, and then cooled to obtain the high-temperature resistant heat insulation material;

[0013] This invention uses commercially available high-temperature resistant adhesive as raw material, mixes it with a pore-forming agent and a thickener, and then directly calcines it to create pores. Through a simple preparation method, a large number of uniform bubbles are generated within the adhesive, significantly improving the material's thermal insulation performance and resulting in a high-performance thermal insulation material. The thermal insulation mechanism of this invention involves introducing air with low thermal conductivity (λ≤0.25w / m·k) into the matrix. This low thermal conductivity air or material has significant thermal resistance to heat conduction and a noticeable coating thickness, thus achieving excellent thermal insulation effects.

[0014] Preferably, the high-temperature resistant adhesive is a mixture of high-temperature resistant inorganic nano-binder and ultra-high-temperature inorganic potting compound TW-2212 from Chengdu Tiandao Chemical Co., Ltd. Both adhesives contain a main adhesive and a secondary adhesive component.

[0015] Preferably, when mixing the high-temperature resistant adhesive, the main adhesive and auxiliary adhesive of the high-temperature resistant inorganic nano-binder are mixed first, then the main adhesive of the ultra-high temperature inorganic potting compound TW-2212 is added and mixed, and then the auxiliary adhesive of the ultra-high temperature inorganic potting compound TW-2212 is added. Since the auxiliary adhesive of the ultra-high temperature inorganic potting compound TW-2212 is a semi-transparent paste, it is added last to ensure uniform dispersion.

[0016] Mix for 20-120 minutes after each addition of new ingredients, then transfer to a speed of 200-450 rpm.

[0017] The mass ratio of the main adhesive to the auxiliary adhesive of the high-temperature resistant inorganic nano-binder in the high-temperature resistant adhesive is 1:0.8-1.2; the mass ratio of the main adhesive of the high-temperature resistant inorganic nano-binder to the main adhesive of the ultra-high temperature inorganic potting compound TW-2212 is 1:0.8-1.2; and the mass ratio of the main adhesive to the auxiliary adhesive of the ultra-high temperature inorganic potting compound TW-2212 is 20:5-7. The resulting thermal insulation material exhibits low thermal conductivity and high mechanical strength.

[0018] The pore-forming agent includes one or more of polyvinyl alcohol, polystyrene, polyethylene wax, polyethylene glycol 2000, and nanocellulose. Polyvinyl alcohol is preferred because it produces smaller pore sizes and lower material density after calcination.

[0019] The thickener includes one or more of sodium carboxymethyl cellulose, starch, agar, pectin, and carboxymethyl cellulose. Sodium hydroxymethyl cellulose is preferred, as it can form numerous hydrogen bonds in aqueous solution, enhancing intermolecular interactions and forming a network structure. This network structure hinders the free flow of solvent molecules, thereby increasing the viscosity of the solution.

[0020] The mass ratio of polyvinyl alcohol to high-temperature resistant adhesive is (2-10):66.6. The addition of polyvinyl alcohol can significantly reduce the density of the material and improve its thermal insulation performance. A good balance is maintained between density and thermal insulation performance.

[0021] The mass ratio of sodium carboxymethyl cellulose to the high-temperature resistant adhesive is (0.1-0.3):66.6. The higher the sodium carboxymethyl cellulose content, the shorter the curing time.

[0022] Preferably, in step 1, the drying process involves drying at room temperature or at 40-60°C for 8-72 hours.

[0023] Preferably, the calcination process involves maintaining the temperature at 250-350℃ for 0.5-3 hours, followed by maintaining the temperature at 600-700℃ for another 0.5-3 hours. This reaction time results in good material forming and prevents cracking and bulging.

[0024] This invention also provides a low-cost, low-density, high-temperature resistant thermal insulation material prepared by the aforementioned method. Its density is 1.2 g / cm³. 3 The temperature resistance can reach 1200℃.

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

[0026] This invention uses a compound of high-temperature resistant adhesive, pore-forming agent and thickener. After calcination, high-density pores are prepared inside the high-temperature adhesive, which greatly improves the thermal insulation performance of the material while reducing the material density. This results in a thermal insulation material with both excellent mechanical and thermal insulation properties, which can be applied to boilers, safe insulation layers and aerospace fields, and can be widely promoted in industrial applications. Attached Figure Description

[0027] Figure 1 This is a physical image of the low-cost, low-density, high-temperature resistant thermal insulation material of Example 4. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0029] The raw materials used in the following specific embodiments were all purchased from the market, and the high-temperature resistant inorganic nano-binder and the ultra-high temperature inorganic potting compound TW-2212 were purchased from Chengdu Tiandao Chemical Co., Ltd.

[0030] Comparative Example 1

[0031] (1) Preparation of the precursor of thermal insulation material

[0032] Place 20g of the main adhesive and 20g of the secondary adhesive of the high-temperature resistant inorganic nano-binder into a 200ml iron can, and stir at 350rpm for 30min at room temperature. Then add 20g of the main adhesive of TW-2212 and continue stirring at 350rpm for 30min. Next, add 6.6g of the secondary adhesive of TW-2212 and continue stirring at 400rpm for 1h. Finally, add 0.2g of sodium carboxymethyl cellulose, stir at 400rpm for 5min, pour into a 20×20×20mm mold, and flatten. Dry at room temperature for 24h, and then in a 50°C oven for 6h.

[0033] (2) Create holes in the above-mentioned thermal insulation material.

[0034] The above-mentioned materials were placed in a muffle furnace with an air atmosphere. First, the temperature was raised to 300℃ at a rate of 10℃ / min and maintained for 120 minutes. Then, the temperature was raised to 650℃ at a rate of 10℃ / min and maintained for 90 minutes. The muffle furnace was then allowed to cool naturally to room temperature. The low-cost, low-density, high-temperature resistant thermal insulation material was thus prepared.

[0035] Example 1

[0036] (1) Preparation of the precursor of thermal insulation material

[0037] Place 20g of the high-temperature resistant inorganic nano-binder main adhesive and 20g of the secondary adhesive into a 200ml iron can, and stir at room temperature at 350rpm for 30min. Then add 20g of TW-2212 main adhesive and continue stirring at 350rpm for 30min. Next, add 6.6g of TW-2212 secondary adhesive and continue stirring at 400rpm for 1h. Add 2g of polyvinyl alcohol and continue stirring at 400rpm for 1h. Finally, add 0.2g of sodium carboxymethyl cellulose and stir at 400rpm for 5min. Pour the mixture into a 20×20×20mm mold and flatten it. Dry at room temperature for 24h, and then in a 50°C oven for 6h.

[0038] (2) Create holes in the above-mentioned thermal insulation material.

[0039] The above-mentioned materials were placed in a muffle furnace with an air atmosphere. First, the temperature was raised to 300℃ at a rate of 10℃ / min and maintained for 120 minutes. Then, the temperature was raised to 650℃ at a rate of 10℃ / min and maintained for 90 minutes. The muffle furnace was then allowed to cool naturally to room temperature. The low-cost, low-density, high-temperature resistant thermal insulation material was thus prepared.

[0040] Example 2

[0041] (1) Preparation of the precursor of thermal insulation material

[0042] Place 20g of the main adhesive and 20g of the secondary adhesive of the high-temperature resistant inorganic nano-binder into a 200ml iron can, and stir at room temperature at 350rpm for 30min. Then add 20g of the TW-2212 main adhesive and continue stirring at 350rpm for 30min. Next, add 6.6g of the TW-2212 secondary adhesive and continue stirring at 400rpm for 1h. Add 4g of polyvinyl alcohol and continue stirring at 400rpm for 1h. Finally, add 0.2g of sodium carboxymethyl cellulose and stir at 400rpm for 5min. Pour the mixture into a 20×20×20mm mold and flatten it. Dry at room temperature for 24h, and then in a 50°C oven for 6h.

[0043] (2) Create holes in the above-mentioned thermal insulation material.

[0044] The above-mentioned materials were placed in a muffle furnace with an air atmosphere. First, the temperature was raised to 300℃ at a rate of 10℃ / min and maintained for 120 minutes. Then, the temperature was raised to 650℃ at a rate of 10℃ / min and maintained for 90 minutes. The muffle furnace was then allowed to cool naturally to room temperature. The low-cost, low-density, high-temperature resistant thermal insulation material was thus prepared.

[0045] Example 3

[0046] (1) Preparation of the precursor of thermal insulation material

[0047] Place 20g of the main adhesive and 20g of the secondary adhesive of the high-temperature resistant inorganic nano-binder into a 200ml iron can, and stir at 350rpm for 30min at room temperature. Add 20g of the main adhesive of TW-2212 and continue stirring at 350rpm for 30min. Then add 6.6g of the secondary adhesive of TW-2212 and continue stirring at 400rpm for 1h. Add 6g of polyvinyl alcohol and continue stirring at 400rpm for 1h. Finally, add 0.2g of sodium carboxymethyl cellulose and stir at 400rpm for 5min. Pour into a 20×20×20mm mold and flatten. Dry at room temperature for 24h, and then in a 50°C oven for 6h.

[0048] (2) Create holes in the above-mentioned thermal insulation material.

[0049] The above-mentioned materials were placed in a muffle furnace with an air atmosphere. First, the temperature was raised to 300℃ at a rate of 10℃ / min and maintained for 120 minutes. Then, the temperature was raised to 650℃ at a rate of 10℃ / min and maintained for 90 minutes. The muffle furnace was then allowed to cool naturally to room temperature. The low-cost, low-density, high-temperature resistant thermal insulation material was thus prepared.

[0050] Example 4

[0051] (1) Preparation of the precursor of thermal insulation material

[0052] Place 20g of the high-temperature resistant inorganic nano-binder main adhesive and 20g of the secondary adhesive into a 200ml iron can, and stir at room temperature at 350rpm for 30min. Then add 20g of TW-2212 main adhesive and continue stirring at 350rpm for 30min. Next, add 6.6g of TW-2212 secondary adhesive and continue stirring at 400rpm for 1h. Add 8g of polyvinyl alcohol and continue stirring at 400rpm for 1h. Finally, add 0.2g of sodium carboxymethyl cellulose and stir at 400rpm for 5min. Pour the mixture into a 20×20×20mm mold and flatten it. Dry at room temperature for 24h, and then in a 50°C oven for 6h.

[0053] (2) Create holes in the above-mentioned thermal insulation material.

[0054] The above-mentioned items were placed in a muffle furnace with an air atmosphere. First, the temperature was raised to 300℃ at a rate of 10℃ / min and maintained for 120 minutes. Then, the temperature was raised to 650℃ at a rate of 10℃ / min and maintained for 90 minutes. The muffle furnace was then allowed to cool naturally to room temperature. The low-cost, low-density, high-temperature resistant thermal insulation material was thus prepared. A picture of the actual product is shown below. Figure 1 As shown.

[0055] Example 5

[0056] (1) Preparation of the precursor of thermal insulation material

[0057] Place 20g of the high-temperature resistant inorganic nano-binder main adhesive and 20g of the secondary adhesive into a 200ml iron can, and stir at room temperature at 350rpm for 30min. Then add 20g of TW-2212 main adhesive and continue stirring at 350rpm for 30min. Next, add 6.6g of TW-2212 secondary adhesive and continue stirring at 400rpm for 1h. Add 10g of polyvinyl alcohol and continue stirring at 400rpm for 1h. Finally, add 0.2g of sodium carboxymethyl cellulose and stir at 400rpm for 5min. Pour the mixture into a 20×20×20mm mold and flatten it. Dry at room temperature for 24h, and then in a 50°C oven for 6h.

[0058] (2) Create holes in the above-mentioned thermal insulation material.

[0059] The above-mentioned materials were placed in a muffle furnace with an air atmosphere. First, the temperature was raised to 300℃ at a rate of 10℃ / min and maintained for 120 minutes. Then, the temperature was raised to 650℃ at a rate of 10℃ / min and maintained for 90 minutes. The muffle furnace was then allowed to cool naturally to room temperature. The low-cost, low-density, high-temperature resistant thermal insulation material was thus prepared.

[0060] The heat resistance and thermal conductivity of the thermal insulation materials prepared in the examples and comparative examples were tested using a Xiangke DRS-2 high-temperature flat plate thermal conductivity tester, following the standard test method for thermal conductivity of insulating refractory bricks in ASTM C182-88 (2004). Additionally, samples were dropped freely from a height of 1 meter onto a cement surface three times from different surfaces. The damage and cracking of the materials were observed to determine their basic mechanical properties. All samples did not crack, indicating that the materials have good mechanical properties.

[0061] Table 1. Density and thermal insulation performance of thermal insulation materials

[0062]

[0063] As shown in Table 1, in Example 1, the density of the insulation material decreased significantly and the insulation performance improved markedly after adding the pore-forming agent polyvinyl alcohol. In Examples 1, 2, 3, and 4, it can be seen that the density of the material gradually decreased with the increase of polyvinyl alcohol. This is because the increased volume of the pore-forming agent reduces the density of the insulation material after sintering. Before Example 4, the insulation performance of the insulation material increased with the increase of the pore-forming agent. This is because the increased amount of pore-forming agent increases the number of closed air cavities in the material, leading to increased thermal resistance and thus improved insulation performance.

[0064] Example 5 showed a lower density but poorer thermal insulation performance. This is because excessive pore-forming agent firstly makes the dispersion of polyvinyl alcohol difficult, and secondly, exceeds the critical value for uniform dispersion of the matrix. This can lead to interconnected bubbles or the formation of large bubbles after sintering, both of which reduce the thermal resistance of the material. Therefore, the thermal resistance of the insulation material will decrease. It can be seen that Example 4 achieved the best effect at a density of 0.363 g / cm³. 3 Under ideal conditions, the insulation effect is optimal; with a 20mm thickness, the temperature can be reduced from 800℃ to 110℃, demonstrating excellent performance. It can be applied to boilers, safe insulation layers, and aerospace applications.

Claims

1. A method for preparing a low-cost, low-density, high-temperature resistant thermal insulation material, characterized in that, Including the following steps: Step 1: Stir and mix the high-temperature resistant adhesive, add the pore-forming agent and stir and mix, then add the thickener and stir and mix, and dry to obtain the preliminary body of the heat insulation material; the pore-forming agent is polyvinyl alcohol; the mass ratio of polyvinyl alcohol to high-temperature resistant adhesive is (2-10):66.6; Step 2: The heat insulation material is pre-calcined to create holes, and then cooled to obtain the high-temperature resistant heat insulation material; The high-temperature resistant adhesive is a mixture of high-temperature resistant inorganic nano-binder and ultra-high temperature inorganic potting compound TW-2212 from Chengdu Tiandao Chemical Co., Ltd. Both the high-temperature resistant inorganic nano-binder and the ultra-high temperature inorganic potting compound TW-2212 contain main adhesive and secondary adhesive components. First, mix the main adhesive and auxiliary adhesive of the high temperature resistant inorganic nano adhesive, then add the main adhesive of the ultra-high temperature inorganic potting compound TW-2212 and mix again, then add the auxiliary adhesive of the ultra-high temperature inorganic potting compound TW-2212. Mix for 20-120 minutes after each addition of new ingredients, at a speed of 200-450 rpm. The mass ratio of the main adhesive to the auxiliary adhesive of the high-temperature resistant inorganic nano-binder in the high-temperature resistant adhesive is 1:0.8-1.2; the mass ratio of the main adhesive of the high-temperature resistant inorganic nano-binder to the main adhesive of the ultra-high temperature inorganic potting compound TW-2212 is 1:0.8-1.2; and the mass ratio of the main adhesive to the auxiliary adhesive of the ultra-high temperature inorganic potting compound TW-2212 is 20:5-7. The calcination process involves maintaining the temperature at 250-350℃ for 0.5-3 hours, followed by maintaining the temperature at 600-700℃ for another 0.5-3 hours.

2. The method for preparing the low-cost, low-density, high-temperature resistant thermal insulation material according to claim 1, characterized in that, The thickener includes one or more of sodium carboxymethyl cellulose, starch, agar, pectin, and carboxymethyl cellulose.

3. The method for preparing the low-cost, low-density, high-temperature resistant thermal insulation material according to claim 2, characterized in that, The mass ratio of sodium carboxymethyl cellulose to high-temperature resistant adhesive is (0.1-0.3):66.

6.

4. The method for preparing the low-cost, low-density, high-temperature resistant thermal insulation material according to claim 1, characterized in that, In step 1, dry at room temperature or 40-60℃ for 8-72 hours.

5. A low-cost, low-density, high-temperature resistant thermal insulation material prepared by the preparation method according to any one of claims 1-4.

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