Preparation method of light-weight high-strength closed-cell thermal insulation material

Abstract

The application discloses a preparation method of light high-strength closed-cell thermal insulation material, and relates to the field of light thermal insulation material, which comprises glassy transformation of a multi-element amorphous system and thermodynamic related knowledge. The method forms a dense glassy substance on the surface of a perlite insulation board. The specific steps are as follows: amorphous powders such as silicon dioxide, calcium carbonate and boron oxide are mixed into a slurry, the mixed slurry is brushed on the surface of a light open-cell thermal insulation material, and high-temperature heat treatment is conducted on the material surface to form a dense glassy substance. Through the method, the surface of the thermal insulation material becomes dense, so that the thermal insulation performance and strength of the thermal insulation material are increased. The method can be used in the fields of building thermal insulation, heat insulation between batteries in a car and the like.

Description

Technical Field

[0001] This invention belongs to the technical field of lightweight thermal insulation materials, specifically relating to a method for preparing a lightweight, high-strength closed-cell thermal insulation material. Background Technology

[0002] Based on the form of thermal insulation, commonly used lightweight thermal insulation materials include fibrous thermal insulation materials and porous materials. For fibrous thermal insulation materials, there are several methods for preparing fibers: blend spinning, sol-gel method, and template impregnation method. Each of these methods has some drawbacks. The blend spinning method requires precise control of the uniformity and stability of the spinning solution, making the process relatively complex and difficult to obtain high-strength fibers with good continuity. The sol-gel method has a complex preparation process, a long production cycle, and the stability of the precursor sol is easily affected by the environment. The template impregnation method has a simple process flow, low raw material prices, does not require expensive equipment, and has a short production cycle, but the strength of the prepared precursor is low. Therefore, it is difficult to obtain lightweight fibrous thermal insulation materials with high strength, high performance, and low cost. Therefore, it is necessary to design an inexpensive, lightweight, high-strength thermal insulation material.

[0003] Perlite is a glassy rock formed from acidic lava erupted from volcanoes and rapidly cooled, named for its pearly, fractured structure. It contains 2-6% water. The melting temperature of perlite is as follows: initial shrinkage temperature 1025℃, softening temperature 1175℃, melting temperature greater than 1500℃, softening temperature range 150℃, and melting temperature range 325℃. Expanded perlite becomes a lightweight, multifunctional new material. It features low apparent density, low thermal conductivity, good chemical stability, wide operating temperature range, low moisture absorption, and is non-toxic, odorless, fireproof, and sound-absorbing, making it widely used in various industrial sectors. Therefore, perlite insulation boards made from expanded perlite have good thermal insulation performance and are inexpensive; however, the presence of pores on its surface can somewhat impair its thermal insulation performance and strength. Summary of the Invention

[0004] In view of the deficiencies in the existing technology, the purpose of this invention is to provide a method for preparing a lightweight, high-strength closed-cell thermal insulation material, so as to reduce costs and enhance the thermal insulation performance and strength of the original thermal insulation material.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a lightweight, high-strength closed-cell thermal insulation material, comprising: forming a dense glass structure on the surface of a perlite insulation board, the specific preparation steps of which are as follows:

[0007] 1) Mix amorphous powder with ethanol in a ratio of 3:1 to 2:1 using a ball mill. Place the polymerized solid in a drying oven and dry it completely at a temperature of 70 to 90°C for 7 to 10 hours. After drying, pulverize it into fine particles. Place the obtained fine particles in an alumina crucible and melt them for 2 to 3 hours until they are completely melted. Pour the melt into cold distilled water to cool it down to below the glass transition temperature to form a glassy state.

[0008] 2) Crush the formed glass powder to ≤45 micrometers, mix it with an organic solution to form a viscous paste-like master glass paste, coat a layer of master glass paste on the surface of the lightweight thermal insulation material; heat-treat it again by holding it in a high-temperature furnace for 10-20 minutes.

[0009] The amorphous powder is composed of silicon dioxide, boron oxide, and calcium oxide mixed in a certain proportion, with the following specific mass percentages: SiO2: 20%–30%, CaCO3: 20–40%, B2O3: 10%–20%, Na2CO3: 10%–20%, MgO: 0.5%–10%, ZnO: 3%–15%.

[0010] The melting temperature is between 500 and 1600°C.

[0011] The temperature of the cold distilled water is 15–25°C.

[0012] The organic solution is one or both of the following: a 10%-15% aqueous solution of polyvinyl alcohol and an aqueous solution of polyurethane.

[0013] The second heat treatment temperature is 600℃~800℃.

[0014] The present invention provides a method for preparing a lightweight, high-strength, closed-cell thermal insulation material. Perlite insulation board is used as raw material, and its surface pores are closed by technical methods to obtain a lightweight, high-strength, closed-cell thermal insulation material that is inexpensive and has good thermal insulation performance.

[0015] Compared with existing technologies, the features of this invention are: 1) The perlite insulation board used has high strength, low thermal conductivity, low density, and low price; 2) The method of this invention is simple and easy to operate, and does not require expensive instruments; 3) After a glass surface is formed on the perlite insulation board, it can effectively block gas from entering the material through pores, effectively reducing the impact of heat convection on thermal conductivity; 4) The smooth glass surface can reflect heat radiation, reducing the impact of heat radiation on thermal conductivity; 5) The dense glass surface can enhance the strength of the perlite insulation board. Implementation

[0016] The embodiments of the present invention will be described in further detail below. Example

[0017] In a ball mill, amorphous powder and ethanol were uniformly mixed at a ratio of 3:1. The specific mass percentages of the amorphous powder were as follows: SiO2: 20%, CaCO3: 30%, B2O3: 20%, Na2CO3: 20%, MgO: 2%, ZnO: 8%. The polymerized solid was completely dried in an oven at 85℃ for 9 hours, then pulverized into fine particles. These particles were then melted in an alumina crucible at 1100℃ for two hours, poured into cold distilled water (25℃), and cooled below the glass transition temperature to form a glassy state. The glass powder was collected and pulverized to a size ≤45 micrometers. It was then mixed with a 10% polyvinyl alcohol aqueous solution to form a viscous master glass paste, which was coated onto the surface of a perlite insulation board and held in an 800℃ furnace for 10 minutes. This yielded a lightweight, high-strength, closed-cell thermal insulation material. Example

[0018] In a ball mill, amorphous powder and ethanol were uniformly mixed at a ratio of 3:1. The specific mass percentages of the amorphous powder were as follows: SiO2: 30%, CaCO3: 20%, B2O3: 10%, Na2CO3: 20%, MgO: 5%, ZnO: 15%. The polymerized solid was completely dried in an oven at 80℃ for 7 hours, then pulverized into fine particles. These particles were then melted in an alumina crucible at 900℃ for two hours, poured into cold distilled water (20℃), and cooled below the glass transition temperature to form a glassy state. The glass powder was collected and pulverized to a size ≤45 micrometers. It was then mixed with a 10% polyvinyl alcohol aqueous solution to form a viscous master glass paste, which was coated onto the surface of a perlite insulation board and held in an 800℃ furnace for 15 minutes. This yielded a lightweight, high-strength, closed-cell thermal insulation material. Example

[0019] In a ball mill, amorphous powder and ethanol are uniformly mixed at a ratio of 2:1. The specific mass percentages of the amorphous powder are as follows: SiO2: 30%, CaCO3: 30%, B2O3: 15%, Na2CO3: 15%, MgO: 3%, ZnO: 7%.

[0020] The polymerized solid was completely dried in an oven at 75°C for 8 hours, then pulverized into fine particles. These particles were then melted in an alumina crucible at 800°C for two hours, poured into cold distilled water (25°C), and cooled below the glass transition temperature to form a glassy state. The glass powder was collected and pulverized to a size ≤45 micrometers. This powder was then mixed with a 15% polyurethane aqueous solution to form a viscous master glass paste, which was coated onto the surface of a perlite insulation board and held in an 800°C furnace for 10 minutes. This yielded a lightweight, high-strength, closed-cell thermal insulation material. Example

[0021] In a ball mill, amorphous powder and ethanol were uniformly mixed at a ratio of 2:1. The specific mass percentages of the amorphous powder were as follows: SiO2: 30%, CaCO3: 30%, B2O3: 20%, Na2CO3: 10%, MgO: 4%, ZnO: 76%. The polymerized solid was completely dried in an oven at 80℃ for 8 hours, then pulverized into fine particles. These particles were then melted in an alumina crucible at 1500℃ for two hours, poured into cold distilled water (20℃), and cooled below the glass transition temperature to form a glassy state. The glass powder was collected and pulverized to a size ≤45 micrometers. It was then mixed with a 12% polyvinyl alcohol aqueous solution to form a viscous master glass paste, which was coated onto the surface of a perlite insulation board and held in a furnace at 750℃ for 15 minutes to obtain a lightweight, high-strength, closed-cell thermal insulation material.

[0022] This method improves the thermal insulation performance and strength of the original insulation material because the glass layer on the surface closes the pores, thereby reducing the impact of heat convection on thermal conductivity. At the same time, the smooth glass surface can reflect most of the heat radiation, further reducing thermal conductivity. And because glass is a dense structure, it enhances the strength of the raw materials.

Claims

1. A method for preparing a lightweight, high-strength closed-cell thermal insulation material, characterized in that: The preparation method is as follows: the surface of the perlite insulation board is made into a dense glass structure, and the specific preparation steps are as follows: 1) Mix amorphous powder with ethanol in a ratio of 3:1 to 2:1 using a ball mill. Place the polymerized solid in a drying oven and dry it completely at a temperature of 70 to 90°C for 7 to 10 hours. After drying, pulverize it into fine particles. Place the obtained fine particles in an alumina crucible and melt them for 2 to 3 hours until they are completely melted. Pour the melt into cold distilled water to cool it down to below the glass transition temperature to form a glassy state. 2) Crush the formed glassy state to ≤45 micrometers, mix it with an organic solution to form a viscous paste-like master glass paste, apply a layer of master glass paste to the surface of the perlite insulation board; and perform a second heat treatment in a high-temperature furnace for 10-20 minutes.

2. The method for preparing a lightweight, high-strength closed-cell thermal insulation material as described in claim 1, characterized in that: The specific mass percentages of the amorphous powder are as follows: SiO2: 20%–30%, CaCO3: 20–40%, B2O3: 10%–20%, Na2CO3: 10%–20%, MgO: 0.5%–10%, ZnO: 3%–15%.

3. The method for preparing a lightweight, high-strength closed-cell thermal insulation material as described in claim 1, characterized in that: The melting temperature is between 500 and 1600°C.

4. The method for preparing a lightweight, high-strength closed-cell thermal insulation material as described in claim 1, characterized in that: The temperature of the cold distilled water is 15–25°C.

5. The method for preparing a lightweight, high-strength closed-cell thermal insulation material as described in claim 1, characterized in that: The organic solution is one or both of the following: a 10%-15% aqueous solution of polyvinyl alcohol and an aqueous solution of polyurethane.

6. The method for preparing a lightweight, high-strength closed-cell thermal insulation material as described in claim 1, characterized in that: The reheat treatment temperature is 600℃~800℃.