Mineral Oil Findings in Recycled Fibre Food Packaging
Recycled paperboard packaging requires verified functional barriers and HPLC-GC-FID test dossiers to prevent gas-phase MOSH and MOAH food contamination.
EVOH Extrusion
Barrier Application
High performance barrier layers are created by melting ethylene vinyl alcohol copolymer and forcing it through a die onto a substrate. During evoh extrusion, the material is typically sandwiched between layers of polyethylene or polypropylene to protect its structural integrity from moisture. The resulting film provides a dense molecular grid that restricts the passage of oxygen and aromas.
Material Adhesion
Compatibility between the barrier polymer and the outer structural layers requires the use of specialized tie resins. Because the evoh extrusion involves a polar material and non polar polyolefins, the layers will naturally delaminate without a bonding agent. These tie layers are coextruded simultaneously to form a permanent bond while the polymers are still in a molten state.
The thickness of the barrier is often less than five microns in a typical food packaging laminate.
Gas Resistance
Maintaining the freshness of sensitive products is the primary function of this technology in the packaging industry. It effectively stops the migration of mineral oils and other contaminants from recycled paperboard into the food. The material remains highly effective against gases but loses its barrier properties if it becomes damp, which is why it is always encapsulated within water resistant plastics.
This encapsulation ensures the package remains a safe container for its entire shelf life.