GAB Isotherm Calculations for Microfibril Barrier Sorption Qualification
GAB isotherm parameters determine microfibril moisture sorption capacity and establish precise water activity thresholds for barrier packaging compliance.
Multilayer Property Factor
Design Ratio
Mathematical relationships determine the combined performance of several different material layers in a single laminate structure. The multilayer property factor quantifies how the thickness and permeability of each ply contribute to the total barrier effectiveness of the package. It allows engineers to predict the oxygen or moisture transmission rate of a finished foil without testing every possible combination.
This calculation is a staple of flexible packaging design.
Calculation Logic
Summation of the individual resistances of each layer provides the total resistance of the entire system. Applying the multilayer property factor involves dividing the total thickness by the sum of the thickness to permeability ratios of all components.
Material Selection
Optimization of the laminate involves balancing the cost of high performance resins with the mechanical requirements of the filling line. A high multilayer property factor indicates that the combination of materials provides a superior barrier relative to the total thickness of the web. This factor helps in identifying opportunities for down gauging where a thinner construction can meet the same shelf life requirements.
The model assumes that the interfaces between the layers do not contribute additional resistance to gas flow. It is primarily used for selecting between different grades of ethylene vinyl alcohol or metallized films.