Adhesive properties of heat-sealed EVAc/PE films in dependence on recipe, processing, and sealing parameters

The investigated peel system in this study consists of a polyolefine-based, coextruded, three-layer film having ethylene-vinyl acetate (EVAc) copolymer at the interface, heat sealed against a biaxial-oriented polyethylene terephthalate film. This system can primarily be found in the packaging industry offering a residue-free and non-destructive peel behavior. The peel force required to separate the joint depends on the mass fraction of vinyl acetate (VAc) in the EVAc copolymer, the processing conditions in the blowing process of the PE/PEVAc film, and on the sealing parameters. In dependence on the processing conditions and sealing parameters, the standard peel system with EVAc copolymer containing 18 wt.% VAc was investigated. The processing parameters were varied among the processing line of the blown film and their influence on the peel properties were studied. As processing parameters the screw speed within the extruder and the resulting layer thickness, the cooling behavior of the film bubble and the...