Which Sealing Film for PP, PET and Paper Cups?

The short answer: the film must match the cup material to seal reliably. As a rule — PP cups pair with PP-based film, PET cups pair with PET-compatible film, and PE-laminated paper cups pair with PE-compatible film. Mismatch the materials and the seal may peel open or fail to bond even when the machine temperature is correct. When choosing film, also check: base-material compatibility, whether the temperature rating suits your hot/cold drinks, and whether the roll width matches your machine.

Why material compatibility comes first

Sealing a cup is essentially heat welding — the sealing head heats the film’s bottom heat-seal coating so it melts and fuses with the cup rim. If the film’s heat-seal layer is incompatible with the cup material, the weld interface never bonds properly: it peels too easily, or the whole sheet lifts and leaks. So the first step is always to confirm what the cup is made of.

Film pairing for three common cup materials

PP cups (polypropylene — most beverage hot/cold cups)

PP cups tolerate heat well and are the most common beverage cup material. Pairing with PP-based film gives the most stable weld for hot and cold drinks. Confirm the temperature rating covers your hot-drink temperature.

PET cups (polyester — mostly cold, clear cups)

PET cups are clear and rigid but less heat-tolerant than PP, used mostly for cold drinks. Pair with PET-compatible film and keep the sealing temperature moderate so the rim does not deform.

PE-laminated paper cups

The body is paper, but the seal relies on the inner PE lamination. Choose film compatible with PE lamination and confirm the rim’s lamination is intact — thin lamination or a folded rim edge will not seal well.

Quick pairing table

Beyond material — three more checks

• Roll width must match the machine: the K-2590SA, for example, uses a 130mm film roll width; choose film that fits your machine’s spec.
• Temperature rating: hot and cold drinks seal at different temperatures — the film’s rating must cover them.
• Print / clarity: printed film needs accurate registration; clear film should show the drink — both matter for brand presentation.

Applicable machine and consumables

The Kai Will K-2590SA sealing machine suits hot and cold sealing with a 130mm film roll width, tight seals and accurate print registration. For film, Kai Will offers several printed sealing-film series. For the correct film-to-cup pairing, send us your cup material and photos for confirmation.

FAQ

Q: Can one film work for all cups?

Not recommended. A film’s heat-seal layer is designed for a specific material; a “universal” film tends to seal poorly on incompatible cups. Choosing by cup material is safest.

Q: Why do paper cups sometimes fail to seal?

Paper cups seal via the inner PE lamination. Thin lamination or a folded rim gap leaves an incomplete weld. Use PE-compatible film and verify the rim lamination quality.

Q: How do I confirm my film matches my cup?

Provide the cup’s material marking and the film spec, and let the Kai Will technical team compare them.

Next step

Gather your cup material, rim diameter and current film spec, then contact Kai Will — we’ll help confirm film compatibility and the machine pairing.

Compiled by the Kai Will technical team. Content is updated on an ongoing basis; the official version is pending Kai Will confirmation.