Resolving Multi Layer Packaging Migration Non Conformance Liability in Food Contact Certification
Resolving multi layer migration liability requires linking batch trace numbers to accredited specific migration reports and contract indemnity clauses.
Adhesive Set Off
Migration Defect
Unwanted transfer of bonding agents from one substrate surface to another occurs during the stacking or rewinding of converted materials. Adhesive set off typically occurs when pressure in a finished reel or pallet causes glue to migrate from the intended joint or coating to the reverse side of the adjacent sheet.
Binding Failure
The chemical composition of the bonding agent determines the speed at which it achieves a tack-free state. If a water-based adhesive remains moisture-heavy when the finished cartons enter a compression zone, the liquid penetrates the opposing board surface. High humidity in the warehouse environment often slows the evaporation rate.
This persistence of tackiness creates a physical bond between stacked items. Moisture migration also plays a part in softening the surface fibres of the recipient sheet. The resulting adhesion occurs during the period of static storage when pallet weight provides constant pressure.
Mechanical Consequence
Removal of the affected sheets or blanks often results in fibre tear or surface picking that ruins the print finish. When the bond formed by adhesive set off is stronger than the internal bond strength of the board, the top layer of the liner pulls away during unpacking. Such damage prevents the use of the material on high-speed filling lines where surface uniformity is required.