Water Resistant Down
By Will Rietveld, Gossamer Gear Trail Ambassador.
Puffy down jackets are very popular and versatile, and more of them are showing up from different companies. Down insulation provides the most warmth for its weight, but its nemesis is water – down readily absorbs moisture. Dampness seriously reduces down's insulation value, and when it gets wet it converts to a mush that leaves you cold.
But that Achilles' heel may disappear with new treatments that apply a molecular level coating to individual down plumules during the down finishing process, making them hydrophobic (water-resisting).
Sierra Designs had this display at the winter 2012 Outdoor Retailer trade show, demonstrating how DriDown (right container) stays puffy, while untreated down (left container) becomes a wet glob.
At the winter 2012 Outdoor Retailer trade show, Sierra Designs introduced DriDown™ which is claimed to "stay dry 7 times longer in the presence of rain, melting snow, or spills, maintain 98% loft after a night in a high humidity environment, and dry 33% faster when it does get wet for a dryer, warmer, more comfortable night's sleep". Also, Brooks-Range is introducing DownTec with the even stronger claim that it "makes the down impenetrable to moisture".
These treatments don't make down waterproof, but if the technology works as claimed, increasing down's water resistance would be a game-changer to make down insulation stay drier and loftier in damp environments, including the absorption of perspiration from within.
Sierra Designs is initially introducing DriDown in five 600-fill sleeping bags (not shown), available June 2012, which are generally of lower interest to ultralight backpackers. More interesting is Sierra Designs' introduction of DriDown in two ultralight 800-fill down jackets, the Tov ($259) and Gnar Lite (left, $229) in fall 2012. Similarly, Brooks-Range will introduce DownTec-treated 800-fill down in their Mojave Jacket (right, $299) which features a Pertex Quantum shell.
As usual, manufacturer claims are "lofty", and they are reluctant to disclose details of the actual technology. My search for more information lead me to the DuPont booth, where people were much more willing to talk about the technology. DuPont has a product called Teflon Down and Feather Protector, which originated in Europe to improve the properties of down bedding. Interestingly, the language in the DuPont brochure describing this product sounds just like (you guessed it) DriDown. I talked with Lisa Hardy, DuPont's North American Marketing Manager, who explained that Teflon Down and Feather Protector is a fluorotelemer and said "DuPont has a unique offering that keeps down and feathers dry."
Even further research leads to Down Décor, the main supplier of down to numerous down garment manufacturers (including Brooks-Range). According to Down Décor, "DryDown (notice the difference in spelling) has been in development for a year, and is based on a nanotechnology from a Belgium company with a presence in Asia".
Whatever the source and chemical composition, the treatment is inexpensive. According to DuPont, it's applied during the down washing process, and then the down is spun and dried to set the Teflon. The result is a monomolecular coating on individual fibers.
For applications in outdoor gear, field testing will be needed to determine if the treatment truly makes a difference. In addition to adding water-resistance, another claimed benefit we would like to see is loft retention. Current issues with high-loft premium down are that it loses loft more readily and dampens more easily; perhaps DryDown treatment can actually improve this natural product.