Expanded polyethylene (ePE)

Membranes are a sometimes overlooked but critical component of waterproof gear. Bonded to the inside of your gear’s exterior shell, this thin inner layer of material has holes that are small enough to keep water from seeping in, but not so small that sweat can't vaporize out. For years, some membranes were made from expanded polytetrafluoroethylene (ePTFE)—an extremely hydrophobic and durable material. They worked well, but there was a problem: ePTFE is made with perfluorinated chemicals (commonly known as PFCs and PFAS). Though safe in finished products, these synthetic compounds can end up in the air and water during manufacturing processes. They’ve also been linked to increased cancer risk. And the compounds don’t break down. Perfluorinated chemicals remain in the environment—and in our bodies—indefinitely. We needed to come up with an alternative.

Nearly 10 years ago, Patagonia partnered with GORE-TEX to start building waterproof gear without PFCs or PFAS for the most technical mountain sports. These non-perfluorinated products would have to withstand the most extreme conditions of snow and backcountry terrain, while also keeping you dry, comfortable and protected. Achieving that level of uncompromising durability has been challenging, but thanks to GORE-TEX's research, development and testing—and Patagonia's own rigorous tests in the lab and field—we’re finally there.

In Fall 2022, Patagonia launched the two-layer Storm Shift Jacket and Pants built with GORE-TEX’s expanded polyethylene (ePE), eliminating the need for long-lasting perfluorinated chemicals while still meeting Patagonia and the GORE-TEX brand’s high standards* for waterproof and windproof protection, as well as breathability.

For Fall 2023, we’ve introduced a three-layer iteration of GORE-TEX ePE that withstands the most rugged and demanding mountain experiences for some of our pinnacle technical Alpine and Snow pieces: the Triolet Jacket and Pants, the Super Free Alpine Jacket, the Alpine Suit, the Untracked Jacket and Bibs, and the Storm Shift Jacket and Pants.

ePE is part of Patagonia’s broader goal to shift toward making gear without fluorinated chemicals across all of our products—with the exception of waders, highly technical gear that they're still fine-tuning—by 2025. As they find more responsible options, they hope to inspire others in the clothing industry to redefine what’s possible for waterproof gear.

*For more on GORE-TEX's sustainability goals, see https://gtx.is/pfcec.