Start with the product, not the film
The right structure begins with four questions: what is inside the pack, how long it must stay fresh, where it will be stored, and how it will be handled. Coffee needs aroma retention and CO₂ release. A retort meal needs seal integrity under heat and pressure. A detergent needs chemical compatibility. A dry snack may need light and moisture protection, but not the same barrier as a foil coffee pack.
The barrier layers
Aluminium foil offers a very strong barrier against moisture, oxygen and light. It is often specified for long shelf life, sensitive flavours and products where light degradation is a real risk. Foil adds cost and can reduce pack flexibility.
Metallized film reflects light and provides a useful moisture barrier at a lower cost. It is a practical choice for many retail snacks and dry goods, but it should not be assumed to perform like foil.
EVOH is a strong oxygen barrier in dry and some moist conditions, but its performance depends on humidity. It is often used in co-extruded and laminated structures where clarity or retort performance matters.
PA / nylon contributes toughness, puncture resistance and flex resistance. It is common in vacuum packs, retort structures and frozen applications.
Match the sealant to the process
The sealant layer is the part of the film that touches the product and forms the seal. PE, CPP and retort-grade sealants behave differently under heat, pressure and contamination. A good structure is not just a list of layers; it is a seal window that works on your machine and with your fill.
Test before you commit
A barrier table is a starting point, not a validation. Ask for samples, run them on your line, and check seal strength, leak performance and real shelf-life conditions. For a new product, a small pilot is almost always cheaper than a full run with the wrong film.
A simple brief that helps
Tell your converter: product type, fill weight, target shelf life, storage conditions, sterilization or freezing, machine type, current structure and the problem you are trying to solve. That is enough to start a useful technical conversation.
Working on a new pack?
Send us the product and target shelf life. We will help with the structure.