People ask for "lidding film" as if it were one product. It is not. There are dozens of combinations, and the part that matters most is not the foil in the middle — it is the thin seal layer on the inside.
That layer decides which cup the lid will bond to, how hard it is to peel, and whether your filling line runs without stopping. Get it wrong and you get leaking cups, torn lids, or lids that will not come off without a fight.
What the film is made of
A typical lidding film is three layers:
Outer layer: where the print sits. PET or paper, depending on the look you want.
Middle layer: aluminum foil, usually 20 to 40 microns. This is the barrier — it stops light, oxygen and moisture.
Inner seal layer: the part that melts and bonds to the cup rim. This is the layer that has to match your cup.
The foil is fairly standard. The seal layer is not.
The seal layer has to match the cup
Cups are made from different plastics, and each one bonds differently:
| Cup material | Typical seal layer | Notes |
|---|---|---|
| PP (polypropylene) | PE-based or PP-based sealant | The most common pairing for dairy and drinks |
| PS (polystyrene) | Special sealant, often low temperature | PS softens easily, so sealing temperature has to stay low |
| PET | PET-compatible sealant | Common for premium dessert cups |
| Paper board | PE sealant | Used for paper tubs and some soup cups |
If the seal layer and the cup do not match, you get one of two problems: the seal is weak and leaks, or the seal is so strong that the lid tears and the customer needs a spoon to open a yogurt.
Peel strength: easy peel or weld seal?
This is the second decision, and it is about the customer more than the machine.
Easy peel: the lid lifts cleanly with a light pull and comes away without tearing. This is what you want for yogurt, desserts, and anything a person opens at a table.
Weld seal: a much stronger bond. The lid is not meant to come off by hand; the pack is opened by cutting or by peeling a separate corner. Used more in industrial and some sterile medical packs.
There is a middle ground too, where the seal is firm but still peels in one piece. Which one you need depends on how the pack is opened, and whether it might be opened by a child or an older person.
Die-cut lids or roll stock?
Two formats, and the choice is mostly about your line:
Die-cut lids: pre-cut circles or shapes, stacked. Simple to run and easy to source, but you pay for the cutting, and the lids have to be fed into the sealer by hand or by a feeder.
Roll stock: a continuous reel that the sealing machine cuts on the fly. Cheaper per lid at volume and faster on high-speed lines, but your machine has to be set up for it.
Either way, the printed artwork has to line up with the cut. That means registration and a dieline agreed before printing, not after.
What goes wrong on the line
Most lidding problems are not the film's fault. These three cause the majority of them:
Sealing temperature. Too cool and the seal does not form; too hot and you melt the cup rim or scorch the print. Every cup material has a window, and it is narrower than people expect.
Pressure and dwell time. A seal needs heat, pressure and time together. Change one and you have to adjust the others.
Product on the rim. A drop of yogurt or sauce between film and cup means no seal at all. Good filling control matters as much as good film.
There is a fourth: a lid specified for one cup, then re-ordered for a cup from a different supplier with slightly different rim geometry. Same material, different fit.
Test before you commit
Do not approve a lidding film from a sample photo. Ask for a small roll and run it on your own machine, with your own cups and your own product. Then check:
Does the seal hold when the cup is turned upside down and shaken?
Does the lid peel in one piece, or does it tear?
Does the seal survive a few days in the fridge and a trip in a chiller bag?
Does the print still line up with the cut after a thousand lids?
Four checks, one afternoon. It saves a much more expensive mistake later.
Tell us your cup material and how the pack will be opened, and we will match the seal layer and send a sample roll to test. More detail on the range is on our aluminum foil lidding film page, and the barrier films behind it sit on aluminum foil roll stock.
