Although common sense would lead us to believe that thicker packaging will always offer better protection, this is not the case with foils. That’s because with any continuous foil, where there are no holes in the foil layer itself, thickness doesn’t matter. Foils are always considered impermeable by their very nature.
All materials have physical space in between their molecules, and gas molecules from the outside atmosphere can work their way into (or escape from) that space. By utilizing barrier films and foils, we’re trying to prevent the natural equalization (or the driving force) from occurring. Foils are considered impermeable because their molecules are so densely packed. In other words, there just isn’t enough space for a water or gas molecule to come in (or escape from) the package—regardless of how thick or thin the foil is.
There is one notable exception to this rule. Foil manufacturers only guarantee that foils 1 mil (or 100 gauge) or greater will be pinhole free. There are many foils used in medical packaging today that are less than 1 mil. In fact, the most commonly used foil is 0.35 mil or 35 gauge. When choosing the right foil for your package, ask yourself:
How sensitive is your product to moisture or gas? The more sensitive your product is, higher gage foil might be the way to go.
Can you afford to take on a bit more risk, thereby lowering your overall packaging cost? If so, choose a lower gage foil.
How long will your product sit on a hospital shelf unused? If your shelf life is one year, for example, you could likely choose a lower gage foil than a product that must maintain efficacy for say, five years. That’s because a pinhole in the foil layer may only affect the shelf life of a product by a few days over one year, equating to weeks over five years.
If you still have questions regarding which is the right foil for you, let me know. I’m here, and always happy to help!