Abstract:

Multilayer bi-axially oriented (bi-ax) barrier shrink films are produced via double bubble (annular process) technology. These barrier bi-ax shrink films are used extensively in food packaging (fresh red meat, processed meat, sausage casing and cheese). In order to protect the food products from microbial growth, chemical changes and physical damage (abuse), various combinations of materials are extruded by the processor. Therefore, these films are fabricated with one or more barrier polymers such as PVdC or EVOH and/or Nylon (with appropriate adhesive and skin layers) to provide high oxygen, moisture and aroma (flavour) barrier with optimum mechanical properties (puncture and abuse resistance). The barrier bi-ax films produced via double bubble technology are annealed as flat or tubular film (via hot rolls, infrared or hot air ovens) to make high, medium and low shrink films which are used as stand-alone film or as tubes to make shrink bags.