We know that the vacuum insulation panel is mainly composed of three parts: core material, barrier film and getter. The barrier film is the "sealed packaging bag" on the outer layer of the vacuum insulation panel. The quality of the "sealed bag" directly affects the performance and life of the vacuum insulation panel. The thermal insulation performance and service life of vacuum insulation panels mainly depend on the continuation and maintenance of the internal vacuum. During use, external gas can penetrate into the vacuum insulation panel through the barrier film, resulting in a decrease in the internal vacuum, affecting performance and service life. Therefore, the barrier film is the key material and key technology of the vacuum insulation panel, and the quality of the barrier film material will directly affect the service life and thermal insulation performance of the product. Let’s take a look at the commonly used materials and development trends of barrier films.
As an important part of the vacuum insulation board, the barrier film mainly plays the role of sealing and wrapping, effectively isolating the communication between the internal core material and the outside atmosphere, and ensuring that the interior of the vacuum insulation board maintains a high degree of vacuum for a long time to maintain its Good thermal insulation performance. However, the barrier film is not absolutely airtight, and air and water vapor can slowly enter the interior of the vacuum panel through the surface of the barrier film and the heat-sealed edge. The barrier film of the vacuum insulation panel is generally made of multi-layer polymer material films, including nylon, polyester, polyvinylidene chloride, aluminum foil, polyethylene, ethylene-vinyl alcohol copolymer, etc. Its function is mainly to coat Insulate and prevent penetration. The barrier film is generally composed of a structural layer, a heat sealing film layer and a gas barrier film layer. The structural layer mainly plays the role of supporting the barrier film; the heat sealing layer is the innermost layer of the barrier film and plays the role of encapsulating the barrier film; the gas barrier film layer mainly functions to block gas and oxygen and prolong the service life of the vacuum board. The performance of the barrier film is mainly through the coating of the core material to isolate heat conduction and prevent gas penetration, and the gas permeability is mainly determined by the gas barrier layer material, which is related to the characteristics of the gas barrier layer. Currently, multi-layer metal and organic materials are commonly used. The composite film is used as the gas barrier layer material. In addition, the performance of the barrier film also includes reducing the influence of heat conduction and heat radiation. A better barrier film can reduce solid-state heat conduction and high temperature heat radiation to a lower level through material improvement.
With the technological development and application of vacuum insulation panels becoming more and more extensive, various manufacturers have higher and higher requirements for surface diaphragm materials. Generally speaking, when selecting barrier film materials, the main consideration is the production cost and normal operation of the barrier film. There are five factors such as wide temperature range, thermal conductivity, air and moisture barrier properties, and tensile strength properties. The development and production of vacuum insulation panels in my country is still in its infancy, and more and more companies and technologies have begun to set foot in this industry. For packaging material barrier films, some companies will choose imported products, mainly because they are used in production. The development and localization of high-barrier raw materials for vacuum plate diaphragm materials are relatively backward, and manufacturers are largely restricted in the selection of diaphragm raw materials. High-barrier materials with excellent performance still rely on foreign imports. With the continuous emergence of new technologies and new materials, under the continuous development of the vacuum insulation industry, relevant domestic enterprises have also launched their own barrier film products, but the stability and appearance of the products are relatively different from those of Japanese and European products. More policies and funds are needed to be relatively skewed. This makes this new type of high-efficiency energy-saving thermal insulation product reduce costs and become more and more widely used.
