Ultra-thin IXPE foam is irradiated cross-linked polyethylene foam rolled down to 0.5 mm and up, while keeping the closed-cell structure that makes IXPE water-resistant, thermally insulating and dimensionally stable. For keyboards, gaskets, speaker meshes and precision electronics, the appeal is simple: millimetre-level sealing and damping in a space thinner than a sheet of card. This guide covers what the material is, which thicknesses and densities are realistic, how it is converted, and how to specify it correctly.
What "Ultra-Thin" Means in IXPE
Standard XPE sheet is normally supplied from 3 mm up. IXPE, made by electron-beam cross-linking before foaming, can be produced far thinner because the cross-link network is set before the gas expands — the cells stay uniform instead of collapsing. Our production range for IXPE is:
- Single layer: 0.5–14 mm
- Laminated (multi-layer, heat-bonded): 15–200 mm
- Width: 500–1800 mm
- Expansion ratio: 3–40 times
In practice, the thinnest commercial gauges — roughly 0.5–1 mm — are used where the foam acts as a gasket, a cushion layer or a dielectric spacer rather than as structural cushioning.
Thin IXPE in Keyboards and Input Devices
Keyboard and switch designers use thin IXPE as a gasket layer and as a damping film:
- Gasket-mounted keyboards — a 0.5–2 mm IXPE strip between plate and case isolates vibration, softening the typing sound and giving the case a more consistent feel.
- Sound damping — closed-cell IXPE absorbs the high-frequency ping that travels through a metal case, without the fibre shedding you get from open-cell acoustic foams.
- Switch and membrane spacing — thin IXPE shims hold consistent compression across large key plates.
Because IXPE is closed-cell, it does not absorb moisture or sweat, and it will not break down into dust inside a sealed device — both important for keyboards that must survive years of use.
Grades and Typical Properties for Thin Sheets
Thinner foam needs a higher expansion ratio to stay soft. The table below shows our measured IXPE grades; the lower-density rows are the ones typically rolled to thin gauges.
| Expansion ratio | Density (kg/m³) | Tearing strength (kN/m) | Thermal conductivity (W/m·K) |
|---|---|---|---|
| 15x | 66.7±8 | ≥4 | ≤0.065 |
| 20x | 50±6 | ≥3.5 | 0.055 |
| 25x | 40±4 | ≥2.5 | ≤0.049 |
| 30x | 33.3±3 | ≥1.3 | 0.045 |
| 35x | 28.6±2 | ≥1.3 | ≤0.040 |
| 40x | 26.8±3 | ≥1.2 | ≤0.040 |
Density is measured to GB/T 6343, tearing strength to GB/T 10808 and thermal conductivity to GB/T 10297. Tensile strength and elongation at break are tested to GB/T 6344 — ask us for the data sheet of a specific grade if you need those values for your design file. Shore hardness of IXPE depends on sheet thickness: for sheets under 3 mm the typical ranges are 55–65 (5x), 45–55 (8x), 35–45 (10x) and 25–35 (15x) Shore C. Thin sheet is harder than thick sheet of the same density, because the surface skin is a larger share of the total.
Surface Treatments for Precision Parts
Thin IXPE is usually converted rather than used as a plain roll. Available surface treatments are corona treatment (for printing and adhesive bonding), embossing, and calendaring for a controlled gloss and thickness tolerance. Sheets can be die-cut, kiss-cut on a carrier liner, laminated to adhesive, or slit to narrow strips for automated feeding.
How to Specify Ultra-Thin IXPE
- Thickness and tolerance — state the gauge and the acceptable range; thin gauges are the hardest to hold, so tolerance drives cost more than density does.
- Density / expansion ratio — a 33 kg/m³ (30x) sheet is the common choice for gaskets; go lighter only if compression force must be very low.
- Hardness target — specify compression force or Shore hardness, and confirm the sheet thickness it was measured at.
- Surface — corona-treated if you will print or laminate; plain if it is a spacer.
- Form — roll, sheet, die-cut part, or adhesive-backed strip.
Common Questions
What is the thinnest IXPE you supply? Single-layer IXPE starts at 0.5 mm. Below that the sheet can no longer be handled reliably as a roll, so for anything thinner we would look at a different material or a laminated construction.
Is thin IXPE the same as foam tape? No. Foam tape is a carrier with adhesive; thin IXPE is the carrier itself. Many customers buy IXPE and laminate their own adhesive.
Does thin IXPE insulate electrically? It is a closed-cell polyethylene dielectric and is widely used as a spacer and insulating layer in low-voltage assemblies; the dielectric strength you need should be validated against your own voltage and creepage requirements.
See IXPE foam grades and full specifications → | Request ultra-thin IXPE samples or a quote →
Related Reading
See also: XPE vs IXPE vs IXPP · XPE foam density and hardness guide · All foam materials