Optimizing the heat sealing parameters of multilayers polymeric films

Polymer–metal multilayers have been widely used for decades in packaging industry, and more recently for vacuum insulation panels for building application. In both cases, the seal zone could represent a weak area for mechanical and barrier properties. The aim of this report is to investigate the heat sealing properties of multilayers composed of one polyethylene layer and one or three polyethylene terephthalate layers coated with aluminum. The quality of seal was quantified by peeling test and the failure mechanisms. In order to optimize the set of heat sealing parameters, a series of mechanical and morphological relevant parameters were measured and compared to the failure modes. A comparison between the sole sealant film and multilayers was performed in terms of range of optimal heat sealing parameters and mechanical behavior of seals. Although they present a much narrower range of optimal properties, the multilayers films show a strong advantage over the single films.