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Introduction to Flamebor Microporous Thermal Insulation Materials

Time : 2023-09-25 Hits : 65

Microporous insulation material is currently the solid insulation material with the lowest thermal conductivity internationally. It is a new type of thermal insulation material that is made up of silica particles with a diameter of tens of nanometers, combined with components such as infrared shading agents and fibers, and undergoes a series of physical and chemical reactions to form tiny nanoscale pores inside the material. Due to the presence of a large number of nanoscale micropores inside, it has a good insulation effect.

The microporous insulation material has a stable porosity structure and is basically a closed cell structure. It not only has excellent insulation performance, but also has good freeze-thaw resistance and sound absorption. Its average lifespan can reach over 30 years under normal use and maintenance conditions. Under normal usage conditions during the lifespan of the structure, it will not be damaged due to dry, humid or electrochemical corrosion, as well as external factors such as insect, fungal or algal growth, or damage from rodents.

The pore size of microporous thermal insulation materials is smaller than the average molecular free path of air (≤ 70nm). The common ones are silica Aerogel materials and microporous thermal insulation panels, which have lower thermal insulation coefficient than air at normal temperature and set temperature. With the continuous deepening of research on insulation materials, while maintaining the original thermal properties of materials, the research on microporous insulation materials is also constantly developing towards practical and engineering directions.

This product utilizes nano porous materials to solve the problem of convective heat transfer, reducing convective heat transfer. Control the thermal conductivity to the limit according to the smallest material particle size and then increase the bonding agent. This enables the product to achieve a nano super insulation material with a lower thermal conductivity than air.

Its ultra-low thermal conductivity, high-temperature use, and strong stability make it a good insulation material used in industry, which is beneficial for reducing product energy consumption and production costs.

1.Definition of microporous insulation materials

It is generally believed that microporous insulation materials refer to insulation materials with a thermal conductivity lower than that of "non convective air" under predetermined usage conditions. Microporous insulation materials have the following characteristics:

1) Almost all the voids in the material shall be below 100nm;

2) Most of the pore sizes in the material should be below 50 nm;

3) The material should have a lower bulk density;

4)The material has a lower thermal conductivity than "non convective air" at room temperature and service temperature.

Microscopic imaging of Flamebor microporous insulation material

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Microscopic presentation of excellent characteristics of Flamebor:

1) Particle diameter less than 100 nanometers;

2) Uniform particle distribution;

3) Reasonable distribution of porosity and pore size;

4)The quantity distribution of shading agents is reasonable;

2. Performance of microporous insulation materials

1) It can work for a long time at high temperatures below 1100 ℃, and its insulation performance is 3-4 times better than traditional fiber insulation materials, making it an excellent substitute for traditional insulation materials.

2) Non combustible: Inorganic and non combustible, Class A fireproof, can be used as a fireproof insulation layer. No smoke or harmful gases generated. It is because the amine radical is a good absorbent. During the high-temperature decomposition process, the free radical generated by the broken sub bridge is quickly absorbed by the amine radical, preventing the reaction from continuing. This phenomenon makes the modified polyimide extremely difficult to burn.

3) Resistance to flame penetration: It has the characteristics of carbon deposition, no fallout, no curling, and no melting under the direct action of flame. After the flame burns, the foam basically remains, just a layer of graphite foam on the surface of the line, effectively protecting the foam structure of the inner layer. Its flame penetration is strong.

4) Green and environmentally friendly: non-toxic and harmless, without inhalable harmful fibers. No harm to construction workers. No ODS substances are generated during production and use, and do not damage the atmosphere. It is environmentally friendly and recyclable.

5) Ultra low thermal conductivity: With a uniform and detailed closed cell structure, the thermal conductivity is only 0.022-0.040 (W/m.K).

6) Stable and safe: The structure is stable under long-term high temperature, without pulverization and aging.

7) Lightweight and efficient: 5-50mm ultra-thin insulation layer, with insulation performance 5-10 times that of traditional insulation materials, saving more space;

8) Low shrinkage rate and less prone to deformation.

9) High compressive strength

10)Good resilience

3.The insulation principle of microporous insulation board

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Based on the micro nano scale heat transfer, when the medium size is reduced to the micro nano scale, the heat conductor can become a thermal insulator. That is to say, when the medium scale is smaller than the average travel of thermal carriers (molecules, atoms, electrons, phonons, photons, etc.), the scale effect and interface effect are obvious, the contact thermal resistance increases, the thermal conductivity decreases, and the heat transfer ability decreases. Therefore, the important difference between micro nano scale heat transfer and macro scale heat transfer is that it reflects the dependence of thermal conductivity, Specific heat capacity and other parameters of medium on scale when heat is transferred.

The main raw material of microporous thermal insulation material is nano powder with large pore volume. Because of high porosity, the thermal conductivity is low; According to the international standard ISO2245-1972, the porosity of insulation products should reach at least 45%, and the porosity of general insulation products should be 70%. However, the porosity of nano powder with large pore volume is 1.8ml/g, so it can be used to produce ultra-low thermal conductivity insulation board.

4. The influence of porosity and pore size on thermal conductivity

After the porosity (or bulk density) of the material is determined, a decrease in pore size means an increase in the number of pores. This change will have two main impacts:

1) The reduction of pore size reduces the amplitude of air convection, resulting in a decrease in the efficiency of convective heat transfer; When the diameter of the gap is smaller than the free stroke of the gas molecules, the gas molecules in the gap are in a static state. The gas molecules not only cannot convection, but also lose the ability of Brownian motion, and most of them are adsorbed on the hole wall;

2)The increase in the number of pores will inevitably lead to an increase in the total surface area of the internal pore walls of the material, which is most evident in an increase in the number of pore walls within a certain thickness, that is, an increase in the solid reflection surface, thereby reducing the efficiency of radiation heat transfer.

Therefore, while maintaining the same porosity of the material, reducing the pore size will lead to a decrease in the thermal conductivity of the material; Moreover, this decrease is more pronounced at higher temperatures, as the porous structure of nanomaterials theoretically limits thermal conduction and convection.

5. The effect of reinforcing fibers on thermal conductivity

Reinforced fibers containing infrared blocking components can effectively reflect heat and reduce thermal radiation and heat dissipation.

6.Comparison between Flamebor Super Microporous Insulation Board and Other Insulation Materials

1) Comparison of thermal conductivity between microporous insulation materials and other insulation materials

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2) Comparison of insulation thickness between Fiberglass microporous insulation materials and other insulation materials

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7. Table of the Relationship between Cold and Hot Surface Temperature and Thickness of Flamebor Microporous Insulation Materials

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