Shelf-Life Prediction for Consumer Packaged Goods (CPG) Bottles

The permeation on thin walls is a mass diffusion problem in a long-term time domain. The application of mass diffusion analysis is limited to continuum modeling, which is not feasible to be used for thin walls, where shell elements are needed. However, the analogy with the heat transfer governing equations allows the FE analyst to simulate the physics of the permeation problem to overcome this limitation with the proper mathematical modeling. The three most common permeants for CPG bottles are CO2 loss for carbonate drinks, O2 ingress for juices, and H2O(g) ingress for powder products. The temperature, pressure, and humidity are the main physical variables that influence the diffusivity and solubility of the bottle wall, usually polymeric materials such as PET. The complete shelf-life analysis brings some additional complexities such as the long-term creep effect (especially for gasified beverages) and the kinetics of the chemical reactions inside the bottle (e.g. vitamin-C and sugar reactions with oxygen for juices), which demands a co-simulation to incrementally compute the permeation simulation with the chemical reactions of the permeants. In this sense, the workflow for the complete analysis gathers several FEA runs considering since the optimization process the material calibration to match with the experimental data until the scripts for doing the post-processing of the raw results. New technological trends to enhance the permeation barrier are coatings (e.g VAC, PVDC, EVOH, and PEC) and multi-layers that have increasingly been applied by the CPG industry. However, the application of these new technologies needs to be balanced to keep market competitiveness due to the significant impact on the materials and manufacturing costs. The objective of this work is to present the state-of-the-art FEA simulation for the shelf-life of CPG bottles including the latest findings for this nature of the problem in conjunction with a CPG company in the avant-garde of this matter.