ePTFE Waterproof Breathable Membrane — Full Technical Specifications
ePTFE Waterproof Breathable Membrane — Full Technical Specifications
What Is an ePTFE Waterproof Breathable Membrane?
Expanded PTFE (ePTFE) is produced by stretching PTFE into a node-and-fibril microstructure with billions of pores per square centimeter. The pore size (typically 0.1–5 µm) is small enough to stop water droplets and dust, yet large enough for water vapor and air molecules to diffuse. This is what gives the membrane both waterproof and breathable behavior at the same time.
Complete Technical Data Sheet
| Parameter | Typical Range / Value | Test Standard |
|---|---|---|
| Base material | 100% expanded PTFE (ePTFE) | — |
| Thickness | 0.03 – 0.20 mm | ASTM D374 |
| Basis weight | 5 – 30 g/m² | ISO 536 |
| Air permeability (透气量) | 200–12,000 ml/min @ Ø10 mm, 7 kPa | ASTM D737 / ISO 9237 |
| Water column (防水) | 2 – 50 m water depth (IP67 / IP68) | ISO 811 / IEC 60529 |
| IP rating | IP67 / IP68 | IEC 60529 |
| Operating temperature | -40 °C to +260 °C (continuous) | IEC 60068-2 |
| Tensile strength | ≥ 30 N/cm | ASTM D882 |
| Chemical resistance | Excellent — most acids, alkalis, solvents | — |
Material Composition & Structure
The membrane is supplied as a bare ePTFE film or laminated to a supporting substrate (PET, PP, or non-woven) for die-cutting and bonding. A pressure-sensitive adhesive (PSA) backing is optional for direct mounting onto enclosures. Pore structure is controlled during biaxial stretching, which determines the final air permeability and water entry pressure.
Key Performance Advantages
- True two-way breathability — air and vapor pass, liquid stays out.
- Wide temperature range — stable from -40 °C to +260 °C, far beyond PU or non-fluorine films (which cap near 120 °C).
- High water column — 2–50 m depth rating versus only 1–2 m for PU / non-fluorine membranes.
- Chemical inertness — resists oils, solvents, and cleaning agents used in automotive and industrial environments.
Typical Application Scenarios
- Automotive ECU, sensors, BMS, and headlight housings
- TWS earbuds, speakers, and microphones (acoustic grade)
- Outdoor and wearable electronics
- Medical device vents and sterile enclosures
- Industrial sensor and control boxes
How to Choose the Right Specification
Selection depends on three variables: (1) required air permeability for pressure equalization speed, (2) minimum water column for the installation environment, and (3) temperature and chemical exposure. For submerged or wash-down parts, specify the 30–50 m water-column grade. For acoustic parts, switch to the acoustic-grade film with ≤ 1 dB insertion loss.
Frequently Asked Questions
What does "breathable" mean for a waterproof membrane?
It means air and water vapor can diffuse through the micropores while liquid water cannot, allowing internal pressure to equalize without letting water in.
What IP rating can ePTFE membranes achieve?
Properly specified ePTFE vents reach IP67 and IP68, protecting against temporary immersion and continuous submersion respectively.
How deep can it be submerged?
Depending on grade, ePTFE membranes withstand 2–50 meters of water column — far deeper than PU or non-fluorine films limited to 1–2 m.
What is the operating temperature range?
-40 °C to +260 °C continuous. PU and non-fluorine membranes typically fail above 120 °C.
Can it resist chemicals and solvents?
Yes. ePTFE is chemically inert against most acids, alkalis, and solvents, making it suitable for automotive and industrial use.
What unit is air permeability measured in?
Air permeability (透气量) is measured in ml/min @ Ø10 mm orifice at a defined pressure drop (commonly 7 kPa).
Is the membrane customizable?
Yes. Thickness, pore size, shape, adhesive, and air-flow rate can be customized to your test standard and enclosure.
Does it affect sound transmission?
Standard ePTFE slightly attenuates sound. For audio parts use the acoustic-grade film with ≤ 1 dB insertion loss.
How is it mounted?
By die-cutting and bonding with PSA backing, ultrasonic welding, or heat lamination onto the enclosure vent.
What certifications apply?
RoHS and REACH compliance; material properties verified per ASTM and IEC test methods listed above.
Request a Free Sample or Quote
Need the exact grade for your enclosure? Contact Mimoyin for free samples, technical drawings, and a customized parameter quote. Our engineering team supports sample testing against your own test standard.
Breathability & Water-Pressure Capability
| Tier | Breathability (ml/min @ Ø10 mm, 7 kPa) | Water pressure | Typical application |
|---|---|---|---|
| Low breathability (high waterproof) | 200–1,000 | 50–30 m | Deep-water / harsh waterproof; custom per spec |
| Mid (balanced) | 1,000–5,000 | 30–2 m | Automotive / general outdoor; custom per spec |
| High breathability | 5,000–12,000 | 10–1 m | High heat dissipation / low waterproof need; custom per spec |
Mimoyin does not sell fixed catalog SKUs. For each project we match the membrane material to your drawing and required breathability, acoustic loss, and water pressure, then produce samples for your validation testing.
Frequently Asked Questions
What waterproof rating do your membranes achieve?
Our ePTFE waterproof breathable membranes achieve IP67 and IP68 protection grades. They withstand immersion at 1 meter depth for 30 minutes (IP67) and continuous submersion (IP68), while maintaining stable airflow for pressure equalization.
Can you provide custom sizes and die-cutting shapes?
Yes, we offer full custom die-cutting services. We can produce membranes in any size or shape according to your specifications, including round, rectangular, and complex custom geometries. Our Class 10,000 cleanroom ensures precision cutting for production volumes.
What is the minimum order quantity (MOQ)?
We support both prototyping and mass production. Free samples are available for testing with 3-5 working days delivery. For mass production, MOQ is flexible depending on the product specification and can be discussed based on your project requirements.
What industries and applications do your membranes serve?
Our membranes are widely used in automotive electronics, lithium batteries, smart wearables, consumer electronics, LED lighting, medical devices, and industrial sensors. Applications include speaker acoustic vents, pressure balance vents, microphone waterproof membranes, and battery venting solutions.
How long is the delivery time for samples and mass production?
Free samples are delivered within 3-5 working days via express shipping. Mass production typically takes 7-15 working days depending on order quantity and customization requirements. We provide one-stop technical support from sample testing to mass production.