Investigation of the resistance welding of multilayers aluminum-coated polymer complexes used as envelopes of vacuum insulation panels

Vacuum Insulation Panels (VIPs) are thermal insulators consisting of a core material enveloped by a high barrier film or envelope required to maintain the vacuum.Multilayered aluminum-coated polymer complex are the common barrier envelopes of VIPs used as high performance thermal insulation in building applications. The multilayer complex is sealed to maintain the vacuum for a long period of time. From a mechanical and barrier properties standpoint, sealed edges represent the weak point of the envelope assembly. This paper investigates the influence of sealing parameters on the properties of the weld. T-peel and tensile tests in combination with Optic Microscopy observations were used to characterize the heat seals. A minimum seal initiation temperature of 115 °C was identified for the studied complex. Peel strength increased sharply to reaching a maximum value at (140 °C–5 s), which considered as optimum temperature–time couple. Above and beyond these values, a gradual decrease was observed and microscopic images indicate the appearance of roll generated by the expelled polymer mass from the center to the edges of the weld which strongly impacts the morphology of the welded area.

► The weld quality is very sensitive to sealing temperature, time and pressure.
► Dependence of welding behavior to the properties of the complex sealant layer.
► The localization of the failure depends upon the welding conditions.
► Appearance of geometric modification of the seal morphology (blister, depression).
► The localization of the failure and the seal morphology are interrelated.