New for this spring 2009 from Swiss brand Mammut is a jacket using a
membrane-based fabric that becomes more or less breathable depending on
temperature.
The
Exteme Cho Oyu Jacket
is a lightweight, supple alpine waterproof hard shell that uses
Schoeller's
c_change
membrane, which, says Mammut 'opens and closes like a pinecone
according to the ambient temperature. At a temperature increase from
10C to 20C, moisture vapour transfer rates or breathability increase by
about 50 per-cent. In the reverse situation, the structure of the
polymer contracts and increases the heat retention properties of the
fabric.
Schoeller call the fabric 'The Bionic Climate Membrane' and it even has
its own web site:
www.c-change.ch
When it's warm or high levels of activity generate heat inside the
jacket, the structure of the membrane opens up to improve moisture
vapour transfer to the outside. Conversely, when things are cooler, the
membrane closes down to conserve heat around the body.
All of which may sound improbable, but bear in mind that when eVent
first appeared, the increased breathability meant that some testers
found the fabric felt less cooler than similar materials because water
vapour could escape more easily taking heat with it.
In lab tests, the fabric is highly breathable. Mammut claims MVT -
moisture vapour transfer - rates of 20,000 g/m2/24h, which, while lab
results are only part of the story, is roughly comparable to eVent,
which is the most breathable conventional waterproof fabric we've used.
The jacket itself is a lighweight alpine design with a close tailored
fit, high reach sleeves, M.A.P hood, under-arm ventilation and more.
Looks good too, in a continental sort of way. So what's the snag? Er,
the Cho Oyu has a suggested retail price of £370, so you'll
need a fairly substantial wallet to go with it.
More Mammut stuff at
www.mammutsportsgroup.ch
