From the Trenches series - Why don't you use...?
In my last post, I tackled a couple of "Why do you use . . .?” questions. In this post, I'll answer a couple of "Why don't you use . . .?" questions. Being a company known for environmentalism, we often get questions about why we don't use certain fabrics, especially when other companies tout them as being the latest and greatest, or at least the ‘greenest.’ In the cases of bamboo and PLA (polylactic acid), both sound pretty green at first glance but in the end aren't all that they seem.
At the outset bamboo does seem the perfect plant to use as a fiber: it is the world’s fastest growing woody plant (conservative estimates cite growth of over 2 feet per day), it generally does not require fertilizers or irrigation, and it can easily be grown organically. So far so good, so what’s the deal?
Patagonia began researching bamboo fabrics back in 2003 and what we found was that although bamboo as a plant is pretty benign, making it into fabric is anything but. It turns out that most bamboo fabric is actually a rayon-like fabric made using a “viscose rayon process” where bamboo is pulped, dissolved with a solvent, spun into strands, and then woven into fabric. Because this process turns cellulose from any plant into a “regenerated cellulose fiber”—what’s commonly known as rayon—there is no chemical difference between rayon fabrics made from different fibers. Unfortunately, the solvent used in this process (carbon disulfide) is not only toxic, factories typically recover only about 50% of it. The other half goes straight into the environment. This was unacceptable to Patagonia so we searched and found Tencel®, a fiber that is more environmentally benign, similar in aesthetics to rayon, and has unique performance attributes.
Tencel® is the brand name of the fiber known as lyocell, a rayon-like fabric made from the fibers of the eucalyptus tree. Much like bamboo rayon, the trees are pulped, processed and spun into a fiber. The difference though is that Tencel® uses a non-toxic solvent in a closed-loop system where none of the solvent ends up in the wastewater. Tencel® shares the soft drape and feel of bamboo rayon without the environmental problems of carbon disulfide. The eucalyptus trees used are grown and harvested as a crop and are certified sustainable by the Forest Stewardship Council.
You might be wondering why we don’t just use the Tencel® process with bamboo. The answer is that we could, but bamboo produces more waste with no additional benefits and since the eucalyptus trees work so well, we have decided stick with them as the source material.
I should also add that not all bamboo fabric is really rayon in disguise. Bamboo does contain bast fibers that can be woven into a natural fiber similar to hemp. As with the eucalyptus, this material and process doesn’t have any real advantages over fabrics made from hemp, so we have elected to continue using hemp.
Why don’t you use PLA?
PLA or polylactic acid is another fiber that has gotten some press of late that Patagonia has chosen not to use. PLA is a corn-based fiber that can be made into fabrics similar to polyester. Again, like bamboo, PLA sounds good on paper: it is made from a renewable resource grown right here in the USA, it makes really nice fabrics and it can be compostable as well. But again there are problems. First off, it’s made from corn and much of the corn currently available for this application is genetically engineered and because we as a company are against the use of genetically engineered crops we can hardly use it for clothing. Using corn also puts us at the mercy of corn as a commodity; its wild price swings in the past two years as a result of the rush to develop ethanol technology are an example of something we’d just as soon steer clear of. Lastly, while PLA is technically biodegradable, it’s not yet available in a form that will disintegrate in that compost pile in your backyard; currently, it is compostable only on an industrial scale. So while we haven’t exactly closed the book on PLA, we’ve opted for now to stick with recycled polyester. There is as yet no shortage of plastic bottles and the fabrics that can be woven from recycled bottles are recyclable as well, meaning your recycled polyester fleece can be recycled when it’s worn out or no longer fits. The net result is that recycled polyester requires less energy and resources than many other textiles, including PLA.
[Bamboo photo, Copyright 2004 firstname.lastname@example.org, via Wikimedia Commons]