Gear freaks with their ear to the virtual ground will be aware, by now, that Gore-Tex has just launched a new, lightweight fabric called Gore-Tex Active Shell which is billed as 'the most breathable Gore-Tex ever' and due out in autumn 2011.
Apparently only three UK outdoor journos made it out to Germany for the initial launch and we weren't among them – grumble, whinge – the good news is that we're scheduled to meet the new fabric over at Plas y Brenin late this month and actually get to use the stuff properly in UK conditions.
The bare bones of it are that the new material sounds like a very light but more breathable version of Pro Shell, though apparently not quite as light as the rather fragile Paclite material, which will carry on.
The key to the new material seems to be a new, thinner version of Gore's PTFE membrane coupled to ultra-lightweight face fabrics – 20 Denier is mentioned in one report. That isn't entirely new though, Mountain Equipment's current Firefox Jacket uses a 20 Denier face already and it's thin and light at a genuine 290 grammes for a full alpine jacket. The other crucial difference, according to LFTO's report, is that the Pro Shell-style liner fabric is actually 'embeded into the PTFE layer' rather than just being laminated to it, which sounds interesting.
Realistically making the membrane thinner isn't going to save that much weight, but what it may do is increase breathability, which is exactly what Gore is claiming. How they've made the membrane thinner is another matter. It's not something Gore talks about openly, but the company's waterproof PTFE fabrics use a very, very thin smear of PU over the inside of the membrane to protect it from contamination.
We're certainly not industrial chemists or fabric experts, but logically the two things that would up breathability would be to either stretch the membrane so the pores in it are slightly larger and pass moisture more rapidly or to make the PU layer thinner, so moisture passes across it more rapidly.
Or possibly both. We're not sure Gore will ever tell us, the company is understandably tight-lipped about its technologies.
So what does it mean for you and me? Well, as of autumn 2011, it seems you'll be able to buy ultra-lightweight and breathable, fast and light kit made from Active Shell and aimed at runners, bikers and fast movers. It'll be minimalist in design to maximise breathability, so fewer pockets and less seam tape and, according to TGO, limited in weight to 330 grammes, which is actually more than a Firefox.
Alarmingly though, the reports coming out of Germany say that while the new fabric is more breathable than both Paclite and Pro Shell, it's actually less durable than Paclite... We find that a little worrying given that we've torn a big hole in a Paclite jacket simply by snagging it lightly on a wire fence.
We're not going to jump to conclusions, but so far, it sounds like the plus side isn't so much the lightness – Pro Shell with a 20D face is, as Mountain Equipment have shown, respectably light – but the increased breathability, which may, at last, mean Gore-Tex can compete with eVent for hot-running, fast-moving types.
We don't expect to see mountain garments made from the stuff just yet, though if the membrane is more breathable as billed then, it wouldn't seem outrageous to expect Pro Shell to get some sort of similar upgrade in the future but with more substantial face fabrics – bear in mind though that the lighter face will be one of the reasons behind the increased breathability, though it may also tend to wet out more easily.
Anyway, enough speculation. We'll bring you more information at the UK launch later this month. In the mean time, you can find reports from the European launch at www.tgomagazine.co.uk and www.livefortheoutdoors.com
