Foam tape is two products in one: a foam carrier that compresses and recovers, and an adhesive that holds it in place. Most field failures come from specifying the adhesive carefully and the carrier carelessly — but it is the carrier that decides whether the joint stays sealed.
The Carrier Is Doing the Sealing
The adhesive holds the tape to a surface. The foam is what closes the gap. Under load the foam compresses, and when the load comes off it has to spring back to its original thickness — otherwise the joint opens, the seal leaks and the tape has to be replaced.
That property is compression set. Our XPE is specified at 10% or lower at 23 ± 2 °C over 22 hours (GB/T 6669). A lower figure means the foam keeps more of its thickness after repeated compression, which is exactly what a gasket or a mounting tape has to do.
Choosing the Carrier Foam
| Property | XPE | IXPE |
|---|---|---|
| Cross-linking | Chemical | Irradiation |
| Expansion ratio | 3–40x | 3–40x |
| Apparent density (GB/T 6343) | 26.8–300 kg/m³ | 26.8–300 kg/m³ |
| Single-layer thickness | 3–15 mm | 0.1–15 mm |
| Laminated build | 15–200 mm | 15–200 mm |
| Compression set (23 °C / 22 h) | 10% or lower | — |
| Water absorption (GB/T 1034) | 0.4% or lower | 0.4% or lower |
- XPE is the standard carrier for gaskets, sealing and mounting where the joint has to carry a load. Choose density against the force the joint has to resist — the 5x to 15x range covers most gasket work.
- IXPE is the carrier for thin tape. Single layers go down to 0.1 mm, which is what makes a low-profile foam tape possible.
- Non-cross-linked PE foam is the softer, cheaper option for low-duty sealing and cushioning where the joint is not cycled.
Adhesive and Release Liner
Foam can be coated on one face or both, with a solvent-based adhesive protected by a release liner. The right adhesive depends on what the tape is bonding to and on the conditions it will see — surface energy, temperature, humidity, and whether the bond has to survive a solvent or a cleaning cycle.
We confirm the adhesive per project rather than quoting a single grade for every job, so tell us the substrate and the environment and we will confirm what we can supply.
Gaskets: Cutting the Shape
Where the seal follows a profile — a housing, a door, a panel edge — the foam is die-cut or routed to a drawing rather than supplied as a straight strip. Foam can be supplied in sheet form or on a roll, laminated with foil or non-woven, and die-cut to a sample or a CAD file.
Specifying Checklist
- Compression. How far will the foam be squeezed, and does it have to keep pushing back?
- Compression set. Will the joint be opened and closed, or held under load for years?
- Thickness. From 3 mm in XPE, from 0.1 mm in IXPE, laminated up to 200 mm.
- Adhesive faces. One face, both faces, or none.
- Substrate. What the foam is bonding to, and under what conditions.
- Shape. Strip, sheet, or die-cut gasket to a drawing.
Send us your gasket drawing or tape requirement →
Foam Tape FAQ
What is foam tape made of?
A closed-cell foam carrier — usually cross-linked XPE or IXPE — coated with an adhesive and protected by a release liner. The foam compresses to fill the gap and springs back to keep the joint sealed.
What is the difference between foam tape and a foam gasket?
They are the same material. Foam tape is supplied as a strip or roll with adhesive; a gasket is the same foam die-cut or routed to the exact shape of the joint it seals.
Can foam tape be supplied with adhesive on both sides?
Yes. Foam can be coated on one or both faces with a solvent-based adhesive under a release liner, and supplied in sheet, roll or die-cut form.
Related Reading
See also: Foam tape & gasket foam hub · Closed cell vs open cell foam · Automotive foam · Contact Bofeng Foam