Structural principle and key technical points of vacuum insulation panel (VIP)

Vacuum insulation panel (VIP for short) is a new type of high-efficiency insulation material developed in recent years. It adopts vacuum insulation technology and consists of three parts: porous core material, getter and gas barrier film. A new type of thermal insulation material made of vacuum packaging technology. The thermal conductivity is extremely low, and the thermal insulation effect is very good. In the early stage of research and development, vacuum insulation panels were mainly applied to the insulation of refrigerators and freezers. In recent years, vacuum insulation panels have only been applied in construction projects.

The vacuum insulation panel adopts the principle of vacuum insulation similar to that of a thermos. From the above introduction, it is known that the porous core material is evacuated through the vacuuming technology, and the getter is added, and the core material in the vacuum state is packaged through the gas barrier film to achieve To achieve the purpose of insulating heat transfer, heat preservation and energy saving. The function of the porous core material is to reduce the heat conduction of the vacuum insulation panel as much as possible, the gas barrier film is to ensure the created vacuum environment to minimize the heat conduction and convective heat transfer caused by the gas, and the getter is to absorb The outside infiltrates the gas and water vapor released from the interior of the vacuum insulation panel and the core material, thereby reducing convection heat transfer and gas heat conduction, and continuously maintaining the vacuum degree of the vacuum insulation panel to maintain a relatively low thermal conductivity and prolong the use of the vacuum insulation panel. life.

Through the above analysis, it is known that there are three key points that determine the thermal insulation effect of the vacuum insulation panel (VIP), that is, the degree of vacuum, the high barrier film and the packaging after vacuuming. Theoretically, the higher the vacuum degree in the vacuum plate, the better the thermal insulation performance. Generally, it should be controlled below 5Pa, or lower. However, in order to achieve a high degree of vacuum below Pa, the performance and working efficiency of the vacuum machine must be considered. There is also vacuum monitoring. The vacuum degree of the vacuum insulation panel is mainly guaranteed by the closed film bag formed by the high barrier film. For this reason, high-barrier films are a critical control point for vacuum insulation panels (VIPs). The quality selection of the film, the selection of the manufacturer, the selection of the adhesive in the compounding process, the equipment, the curing, the compounding sequence, and the heat sealing are all important control links that cannot be ignored. The quality of the package is directly related to the quality of the vacuum board. To this end, the encapsulation of the VIP is also a critical control point (VIP).

There are three ways of heat transfer, heat conduction, convection heat transfer and radiation heat transfer. The vacuum insulation panel is based on this theory to prevent these three forms of heat transfer as much as possible. The heat transfer in the vacuum insulation panel consists of four parts: the solid heat conduction of the core material, the heat conduction of the gas in the plate, the radiation heat transfer and the convection heat transfer. By continuously reducing the thermal conductivity of each part, the total thermal conductivity of the vacuum insulation panel can reach a low value, and the low thermal conductivity can reach below 0.002w/m.k. At present, the vacuum insulation panel is a kind of thermal insulation material with advanced technology and good thermal insulation effect.