Probably every “green” retailer whose product lines include clothing, bedding, or any other textile products carries bamboo products and claims that they are eco-friendly. A short on-line bulletin from the US Federal Trade Commission comes close to calling these claims fraudulent and makes the following points:
- The soft bamboo fabrics on the market today are not made from bamboo fibers. They are rayon.
- Like all rayon, bamboo fabrics are made using toxic chemicals.
- Making fabric from bamboo fibers is expensive, and the cloth does not have the smooth texture of rayon.
- No traits of the original plant remain in the finished rayon–specifically including bamboo’s anti-microbial properties.
- Elsewhere, the FTC even denies that bamboo fabrics are biodegradeable
So is bamboo fabric eco-friendly? Although I link to only one source, I have read numerous descriptions of bamboo fabric. The one I cite happens to deal with more questions than any other single source. Every one of them describe a difference between bamboo linen and bamboo rayon. In other words, the FTC’s bulletin is factually correct but improperly implies that those who claim that bamboo fabric is eco-friendly don’t acknowledge that they are selling rayon.
Bamboo linen is made by an ancient mechanical process. Linen itself, of course, is made from flax. The process of extracting the fibers from either plant and making cloth with it are similar enough that reference to bamboo linen should not confuse anyone.
First it is necessary to crush the woody parts of the bamboo and ret them with a natural enzyme. That leaves a gooey mass, which is combed to produce fibers and then spun into yarn. The process is traditionally labor intensive, time consuming, and expensive. The Swiss company Litrax has automated it and manufactures bamboo linen on a large scale. At a very fine thread count, it is probably soft enough to compete with the more common bamboo rayon.
The Chinese have invented a process of extracting cellulose from bamboo and making yarn from that, as opposed to fiber. Using cellulose requires a chemical process similar to that used to make rayon. The process for making rayon originated in the 1880s. It is not quite a natural fabric because of the manufacturing processes used to make it, but it is not quite a synthetic fabric like the newer ones made from petrochemicals.
The original rayon was made from wood pulp. The same basic process can use any plant material with suitably long molecular chains. Because it was developed long before anyone started to care about protecting the environment, the original process produced a lot of pollution. Like everything else of similar vintage, newer approaches to controlling the process have greatly cut down on negative environmental impacts, but have not yet eliminated them entirely.
Rather than crushing the entire bamboo trunk, the process of making bamboo rayon begins with steaming it to extract the soft inner pith. It also uses the leaves. Where retting fibers for linen involves soaking them in natural enzymes, producing rayon requires that this pith be soaked in sodium hydroxide.
The resulting cellulose pulp is forced through sieve-like nozzles into a bath of sulphuric acid, where it hardens into viscose fiber threads. Creating the viscose and spinning it into yarn is no different from making viscose from wood pulp. The phrase “bamboo rayon” therefore is not some bureaucratic gobbledygook. It is a legitimate distinction between the mechanical process of producing linen and the chemical process of producing rayon.
How bamboo rayon is eco-friendly
Do less than ideal environmental impact of the manufacturing process invalidate claims that bamboo fabric is eco-friendly? Even the FTC points out that bamboo grows quickly and requires little or no pesticides. Ultimately, the environmental difference between bamboo fabric and any other fabric boils down to the fact that it is made from bamboo and not some other crop. I have described growing and harvesting it in an earlier post, Versatile, Sustainable Bamboo.
Have You Been Bamboozled by Bamboo Fabrics? / US Federal Trade Commission
Bamboo Facts and Information / Green Earth Bamboo
Photo credit Some rights reserved by makenzie and john [Link to Flickr no longer works.]