Effects of Corona Treatment on Surface of Aluminum Foil for Retort Pouch

Retort pouch is one kind of flexible packaging which is made from plastic film or aluminum foil laminating
together. Generally, retort pouches will use adhesive to combine each layer of film or foil together. If the lamination between each layer is not good enough, the delamination of each layer might occur. Therefore, the effects of corona treatment on surface of aluminum foil for retort pouch (PET/Al/CPP) were studied. This research was aimed to compare bond strength ability of Al/CPP layer, seal strength, and tensile strength of laminated film (PET/Al/CPP), both before and after sterilization. Moreover, it was aimed to compare the shelf life of laminated film (PET/Al/CPP) that held ketchup and tuna for a period of 7, 14, 21, and 30 days. There were five samples used in this experiment, the laminated film without corona treatment on Al surface and the laminated film with corona treatment on Al surface at 2, 2.5, 3, and 4 kW. The results showed that the laminated film with corona treatment (in all levels) on aluminum surface had higher bond strength, seal strength, and tensile strength than the laminated film without corona treatment on aluminum surface. The results of the shelf life of laminated film (PET/Al/CPP) that held ketchup and tuna paste for a period of 7, 14, 21, and 30 days showed that the bond strength ability of the film without corona treatment on aluminum decreased and the laminated film was delaminated on Al/CPP layer. In a way, the bond strength ability
of laminated film with corona treatment (in all levels) on aluminum slightly decreased. It was also indicated that the level of voltage on corona treatment did not statistically affect bond strength ability of Al/CPP layer, and seal strength and tensile strength of laminated film (PET/Al/CPP).