However, the Gore membrane is the exact same as the XCR which means the breathability, when comparing just the membrane, is the same.
Exactly my idea. I do not contest this.
This info I obtained from Alan DIxon of backpackinglight.com. Alan is considered one of the most respected authorities on w/b performance fabric in the outdoor industry and is not affiliated with any company.
Alan Dixon's article about waterproof/breathables was one of the primaryn reasons for me to take a subscription on BPL
I did some research on Windstopper and couldn't find anything specifically on how it works. I did surmise that it probably doesn't include the PU membrane, but instead is meant not to be durably waterproof like the other Gore membranes, but maintain it's windproofness even if it is contaminated. Gore's website did say that it uses a hydrophobic 'coating' to keep external moisture from seeping through. However, once this membrane become contaminated with dirt and oil it will leak, thus it is considered only a water resistant and windproof membrane. You are right in saying that Windstopper most likely has the same breathability as the 1st generation Gore or similar to eVent. Windstopper should be in another category of laminates, not in the waterproof/breathable discussion. Thanks for the correction. <img src="/forums/images/graemlins/tongue.gif" alt="" />
I suspect that the hydrophobic coating refers just to the hydrophobic properties of the PTFE membrane and not a specific coating.
Though you would think that with as much time as Gore has had in figuring out how to get rid of the PU component from it's membrane, it hasn't. The fact is that it still uses it to fight the contamination issue. Until they figure out how to maintain the surface energy of the membrane without using PU, it will never be as breathable as eVent no matter what kind of marketing spin Gore uses.
I know they still use the PU-layer. But the strange thing is that already as early as 1994, Gore did figure out how to coat the inner structure of the PTFE layer. That's much earlier than BHA with eVENT. For some reason they've never taken the step to bring a product to the market that relies completely on this coating. Even more interestingly, I 've read several documents which seem to describe things like the XCR membrane, paclite, GTX soft shell, stretch gore-tex and even pro shell in which this inner coating was added to the PTFE layer, making the PTFE layer itself also oleophobic. But for some reason, always a PU coating was added on top of the PTFE layer. I still don't understand why they would use both the inner coating and the PU-coating unless they're afraid of durability issues (the argument they use against eVENT)