A barrier film is a layer in flexible packaging whose job is to slow something down. Oxygen staling a roasted product, water vapour softening something crisp, light degrading a pigment or an oil, aroma escaping from coffee or leaking into it from a neighbouring product. There is no universal barrier, so the question is never whether a film has barrier properties, it is which threat it addresses and how well.
How barrier is measured
Two figures do most of the work:
- Oxygen transmission rate. How much oxygen passes through a defined area of film over a defined period. Lower means a tighter oxygen barrier.
- Water vapour transmission rate. The same idea for moisture.
Both are measured under specified temperature and humidity conditions, which is why two quoted numbers are only comparable if the test conditions match. Ask for the conditions alongside the number, and ask in writing.
The common structures, ranked by tightness
| Structure | Barrier character | Trade off |
|---|---|---|
| Aluminium foil laminate | The tightest oxygen, moisture and light barrier in common use | Opaque, higher cost, complicates recycling |
| Metallised film | Strong barrier, close to foil for many products | Still opaque, still a mixed material |
| Transparent high-barrier layer | Good oxygen barrier with product visibility | Moisture sensitivity varies by layer chemistry |
| Polyester outer with a sealant inner | Moderate barrier, good print surface and strength | Not sufficient alone for oxygen-sensitive products |
| Single-layer polyethylene | Decent moisture barrier, poor oxygen barrier | Cheapest, suitable for short shelf life |
Most real packaging is a laminate of several of these, because each layer is chosen for a different job: one prints well, one blocks oxygen, one seals reliably under heat.
Barrier is not the whole pack
A perfect film with a poor seal has no barrier at all. The seal is where most barrier failures occur, followed by the zipper, the valve and any tear notch that cuts too deep. When you specify a barrier structure, specify the closure and the seal width alongside it, and test filled units rather than empty film.
The same applies to the carton. A pouch inside a printed carton gets its barrier entirely from the pouch. The carton adds light protection, stacking strength, print area and shelf presence, and none of those are barrier. Do not let a handsome carton stand in for a film decision.
Ordering
Minimum order is 100 units, and pricing starts from about $0.48 per unit at bulk volumes, confirmed on your written quote. Die and plates, design support, US shipping and a digital proof before anything prints are included. Turnaround is stated per product across three lanes: rush with expedited production and air freight, standard by air, cost saver by sea, from about 7 business days, plus 2 to 5 for delivery. Specialty imported items can run up to about 12 weeks. Production is in West Chicago and in Guangzhou.
For a flexible format that leans on barrier structures, see mylar bags, and the coffee box guide covers how a barrier bag and a printed outer work together. Tell us the product, the target shelf life and the threat you are protecting against when you request a quote.
