Managing Dual Use Additives Information Flow in Plastic Packaging Declarations
Dual use additive management demands specific identity flow from resin compounders to food packers to satisfy direct food additive maximum limits.
Polyolefin Film
Meaning
Thermoplastic membranes derived from ethylene or propylene provide a versatile medium for flexible packaging and industrial liners. A polyolefin film is characterized by low density and high chemical resistance. Production occurs through blown or cast extrusion processes.
Barrier Performance
Molecular structures in these polymers naturally resist the passage of water vapour. A standard polyolefin film prevents the dehydration of contents or the ingress of moisture from the environment. While the oxygen barrier is lower than that of some specialty resins, it can be enhanced through multi-layer co-extrusion.
Versatility allows the material to be used for both frozen food and dry goods.
Sealing Quality
Thermal properties allow for the creation of strong, hermetic bonds at relatively low temperatures. The wide sealing window of a polyolefin film ensures consistent performance on high-speed packaging lines. Bond strength prevents the failure of the pack during transit and storage.
Moulders often blend different grades of polyethylene to optimize the balance between stiffness and seal strength.
Extrusion Variable
Processing conditions like the blow-up ratio or the chill roll temperature dictate the final physical properties. A polyolefin film can be oriented in one or two directions to increase its tensile strength and clarity. Oriented layers provide the necessary puncture resistance for industrial shipping.
Correct selection of the orientation ratio ensures the material meets the application requirements.