This PFAS-free oleophobic waterproof breathable membrane is engineered for environments contaminated with oil mist, such as gearboxes, compressors, and hydraulic reservoirs. It actively repels both water and oil, preventing membrane fouling and maintaining consistent airflow. The oleophobic treatment is completely fluorine-free, using a hydrocarbon-based nanotechnology. The membrane can be custom engineered in thickness, pore size, and air permeability to match specific oil mist challenges, and is available in sheets, rolls, or die-cut parts with oil-resistant adhesive.

Oil mist generated by meshing gears or compressor pistons coats traditional vent membranes, blocking pores and stopping pressure equalization. This causes seal leaks and lubricant expulsion. While oleophobic ePTFE exists, it still contains PFAS in the base material. A PFAS-free alternative must deliver equivalent oil repellency without fluorine chemistry. Most standard polyolefin membranes are oleophilic and fail immediately in oily mist.

We have developed a PFAS-free membrane with a covalently bonded oleophobic surface treatment. The membrane achieves AATCC 118 oil repellency grade 7, meaning it resists penetration by oils with surface tensions as low as 20 mN/m. In accelerated oil mist tests, it retains over 90% of its initial airflow after 500 hours, while standard membranes clog in under 50 hours. This solution enables PFAS-free breather plugs for oil-filled assemblies, meeting both performance and regulatory needs.

• Membrane: PFAS-free polymer, oleophobic

• Oil repellency: Grade 7 (AATCC 118)

• Water entry pressure: > 50 kPa

• Air permeability: 250–500 ml/min/cm²

• Temperature: -30°C to 120°C

• Available formats: Rolls, sheets, die-cut pieces

• Adhesive: Oil-resistant silicone PSA

Designed for gearbox breather vent patches, differential cover membranes, air compressor head space vents, hydraulic tank breathers, and chain oiler reservoir vents. It can be integrated into metal or plastic vent plugs as the core functional layer.

The oleophobic surface causes oil droplets to bead up and roll off the membrane surface without wetting it. This prevents the formation of a liquid film that would block pores. The microporous structure underneath remains open for air and vapor transfer. The treatment is molecularly bonded, meaning it does not leach out or wash off, providing long-term resistance to degradation.

Characterize the oil type and mist concentration in your application. Share this data with us for a recommendation on pore size and oleophobic grade. Consider adding a labyrinth shield on the housing side to reduce direct splash impact. For high-viscosity oils, we may suggest a slightly more open pore structure. Trial samples in an actual oil mist test rig before full specification.