Meaning
Phenomenon describing how a migrating substance divides itself between an adhesive resin and adjacent structural polymers. Proper tie layer partitioning determines whether a contaminant remains trapped within the inner structure or migrates toward the product. This mechanism depends heavily on the chemical affinity between the migrant and the adhesive resin.
Solubility Ratio
Equilibrium distribution is reached when the chemical potential of the migrant is equal in the tie layer and the structural layer. Tie layer partitioning is characterized by a dimensionless constant that represents the ratio of concentrations at the interface. If the migrant is highly soluble in the adhesive, the tie layer can act as a reservoir.
This storage effect can either slow down or accelerate the arrival of the migrant at the surface.
Adhesion Integrity
Presence of high migrant concentrations in the adhesive can sometimes weaken the bond between the functional barrier and the outer skin. Tie layer partitioning influences the mechanical stability of the multilayer film over time.
Barrier Delay
Effective modeling of the lag time in a complex film requires an accurate account of this distribution. Tie layer partitioning is a major factor in the design of functional barriers for recycled content. This understanding allows for the creation of safer food packaging structures.
