| The glass fiber core vacuum insulation panel(GF-VIP) is a kind of super thermal insulation material which is famous for its thin thickness, light weight and very low thermal conductivity, and has been applied in the cold chain of refrigerators. But it has the defects of low compressive strength and short service life due to the loose and porous structure of glass fiber cotton felt, which limits its application in the advanced fields like aviation, spaceflight, navigation and so on. In this paper, a new kind of aluminum foil and superfine glass fiber laminated core was presented; then the VIPs with different laminated structures were obtained throughthe vacuum heat sealing.Thermal conductivity, flexural and aging properties of VIPs were tested and compared; the effect of the aluminum foil on the performance of VIP was analyzed tooptimize the laminate structure.The results showed that firstly, a good compatibility was found between aluminum foil and glass fiber, there was no occurrence like puncture. Secondly, aluminum foil in the ultrafine glass fiber laminated core reduced the rebound rate and increased the bending strength of VIP.Thirdly,the pressure sensitivity of GF-VIP was reduced by the oxidation ofaluminum foil to absorbpartially infiltrated gas. Fourthly, the wet core of thickness less than 1mm and aluminum foil with 0.03 mm thickness had a good coupling effect based on the high thermal conductivity and high heat radiation of aluminum foil itself.The structure of the existing products were optimizedin the paper, for the wet felt glass fiber core VIP with 3.5?m average fiber diameter and 30 stacked layers of each thickness is 0.6~0.8mm, under the same process conditions, the VIP with the structure of each 10 layers of glass fiber cotton felt spaced one layer of aluminum foil owned the relatively low thermal conductivity of 1.494mW/(m?K). On this basis, the simplified mathematical model was used to predict the service life of VIPs, it could be found that the natural aging life of VIP with the "10GF+1Al" structure was more than 70 years, which was better than that of pure glass fiber core VIP with a service life up to 60 years. |
