Migrational behaviour of food grade PP

Plastics for food packaging applications must assure the organoleptic and t oxicological safety of the foodstuff during the contact time. Specific migr ation tests must be performed to verify that migration is below the limit v alues fixed by law. To simplify the control procedures, much effort is dire cted toward establishing the relation between the specific migration of a g iven substance and its residual amount in the plastic. Therefore, a deeper knowledge of the migration behavior of food grade plastics is highly desira ble. Within this frame, a food grade polypropylene, processed by two differ ent technologies (cast-film extrusion and injection moulding), was contamin ated with three model substances, which were used as migration tracers. The samples were analyzed to evaluate their specific migration values in isooc tane, in 95% ethanol, and in 3% acetic acid. The results obtained were rela ted to the residual amounts of the migrants in the polymer and explained on the basis of the structure (crystallinity, orientation) of the artifacts.