What metrics are used to determine the performance of a DWR? Are there specific tests/numbers a coating must pass to be considered for widespread application?
Hi Olivia, there are a number of tests and standards used to evaluate DWR! Of course, one must first understand the end use in which the DWR must perform, and one must also have an idea of how long they need it to last against various challenges. A 30 day alpine expedition in a hardshell has a different set of exposure and needs than a day surfing in board shorts!
In general, DWR performance can be boiled down to a variety of performance attributes including wet pickup, oil repellency, durability to abrasion, durability to home laundry, and simple measures of water beading. ASTM, ISO, JIS and other testing bodies have a multitude of standard test methods that can be used "as-is" or modified to evaluate a chemistry/textile combination for a specific end use.
Thanks for the great question!
Great that you arrange this discussion.
Yesterday I heards Stefan Posner talk about the different assessments of the different C4/C6/C8 chemistries and their alternatives. It seems that most of the alternatives haven't been tested enough to confirm that they are much better. Which research needs to be done now? Which piece of advice would you give to other outdoor brands and the wider community of the apparel sector in respect of finding a viable and "safer" way forward? How much collaboration between brands is taking place in this respect? Is this a topic that falls strictly under "IP" rights?
We all understand that DWRs are needed in some applications, such as on tents to keep occupants dry and safe. However, it seems DWRs are widely applied to apparel and equipment when this function is not needed. Are steps being taken to reduce the use of DWRs where they are not necessary?
What are the fears associated with perfluoroalkyl acrylates - aside from PFOA contamination? Have they been proven to break down to PFOA in the environment? Or are there other hazards associated with PFAA's? Concerning available alternatives, could they potentially be worse for the environment if you have to use more (and possibly re-apply more often) to achieve the same performance as C8?
How exactly are PFCs from raincoats transmitted into the natural environment: manufacturing aerosols, wastewater, degradation from raincoat use, landfill run off? Are there resources that describe this mechanism?
Definitely overprescribed. In my view, with the basis of our years of research, we now only adress so called essential uses of fluoro Chemistry for instance for work wear etc where the oil repellence is essential and a matter of Life an Death. Having said that the highly fluorinated chemistry especially C8 is still the best technology from a performance perspective but not from a toxicological and environmental perspective. So me and my researcher colleagues work hard to define the fine line between essential and non essential uses of fluorinated DWR treatments then for water repellent properties.
Thanks Stefan. Can you say more about essential vs. non-essential uses? Have you seen the viewpoint of brands change as we learn more about the impacts of perfluorinated chemistries? If so, have these changing views affected use patterns?
Matt: Would like to get your input too from Patagonia's perspective.