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28 June 2017 01:29AM
Research & Regulations Catch up with “Bamboo” Textiles Print E-mail
Written by aatcc.informz.net   
03 Sep 09
You can find "bamboo" textiles anywhere from discount superstores to high-end retailers. And the labels and claims associated with these products are as varied as the sources. For consumers and retailers, there has been little reliable information or guidance available on the validity of these claims. Fortunately, this is quickly changing.

Naming the Fiber
Fiber content is important to consumers. It is also important to governments, both in terms of protecting consumers and in assigning proper tariffs and quotas. Naming a fiber incorrectly can damage a company's reputation and result in heavy fines. So, how should we refer to so-called bamboo textile fibers?

Bamboo Fibers-the Real Thingbamboo1a.jpg
There are no standard identification methods for bamboo, but it is possible to separate the fibers from the other bamboo stalk material and create a textile yarn. Such "natural bamboo" or "mechanically processed bamboo" fibers would be recognizable as bamboo under a microscope. As bast fibers, they would create a fabric similar to linen, with thick and thin regions, and a stiff hand.

At a July 2008 workshop sponsored by the US Federal Trade Commission (FTC), Peter Hauser, North Carolina State University, did not think it was likely that items labeled as containing bamboo were made with such natural bamboo fibers. "According to the references I found, [this process] is probably not used very much now because of the time, labor, and cost in making yarn from this process." As of mid-August 2009, FTC staff had still not found any textile items containing actual bamboo fibers.

Regenerated Cellulose
bamboo2.jpgBy far, the most common way to create fiber from bamboo is the rayon (viscose) process. Cellulose (a major component of bamboo and other plants) is dissolved, filtered, and extruded to form fibers. These fibers produce soft, smooth fabrics. According to fiber labeling regulations in the US and elsewhere, this regenerated cellulose must be identified as rayon or viscose-not bamboo. The FTC recently charged four companies with "falsely and deceptively labeling and advertising their clothing and textile products as bamboo, when they should be labeled and advertised as rayon." The Canadian Competition Bureau has also issued guidance on labeling products derived from bamboo.

Hauser suggests bamboo may also be processed into lyocell fibers. The FTC classifies lyocell as a sub-category of rayon produced by organic solvent spinning. Lyocell fibers are also considered regenerated cellulose and would be labeled as lyocell.

So, unless the fibers are actually retted from the bamboo stalk, the label in most countries can NOT list bamboo in the fiber content. The label should indicate that the product is made with rayon (or possibly lyocell).

A Possible Compromise
A label of "rayon made from bamboo" has been proposed by several parties and is allowed by several governments as long as it is true and can be substantiated. But proving the fiber is made from bamboo may not be easy.

Janice Gerde, US Customs and Border Protection, says, "So far, I have found research reports dating to the early 1930s, using various instrumental approaches. And the upshot for the studies that we have seen so far is that once the cellulose is simply cellulose, the source cannot be differentiated." She has first-hand evidence too. FTIR testing of samples labeled "bamboo" matched a reference spectrum for viscose rayon, with no identifiable variations.

The FTC demands "competent and reliable" evidence but does not define this evidence more specifically. Since there is no way to identify bamboo once it becomes rayon fiber, a manufacturer wishing to define its rayon as "made from bamboo" may have to provide evidence tracing its supply chain back to the plant source. Korin Ewing, FTC staff attorney, says the commission will make a case-by-case determination of what constitutes adequate evidence for the "rayon made from bamboo" label.
Why Bamboo?
Why go to so much trouble just to get an extra word on a fiber label anyway? Well, it's all about marketing. Plain old "rayon" is accurate, but not very appealing. Including the word "bamboo" evokes positive images and associations for customers and differentiates a product from the competition. This is where things get complicated. Many of those positive images are based on assumptions and marketing messages that have been proven false.

Environmental Claimsbamboo3.jpg
The good news is that bamboo is a low-impact crop. It doesn't require much water and it grows quickly. Proponents also claim it is inherently pest-resistant so chemical pesticides are unnecessary.

The bad news is that rayon manufacturing is not so environmentally-friendly. Strong chemicals are used to break down the cellulose. After the polymer forms, the chemicals need to be removed by multiple washes. Like most industrial manufacturing, the process requires high water and energy use, and produces air and water pollution.

Rayon is not considered biodegradable despite its natural origins. The FTC warns manufacturers to avoid such claims, stating that rayon products "will not break down in a reasonably short time after customary disposal."

Bamboo claims are not the only "green" statements currently under scrutiny. Ewing says there has been an increase in such claims, and in consumer interest in eco-friendly options. To help sort out the confusion, the FTC recently developed Green Guides. FTC Chair William Kovacic says the Guides are "a key element" to educate businesses and consumers. The FTC also hopes to "engage in a process of research so that we better understand what consumers are taking away from individual ads."

Performance Attributes
There's good news and bad news here too. Hauser says, "there is a material in the bamboo stalk itself that has antimicrobial, antibacterial properties." Natural bamboo also has pores that allow high levels of moisture transport and breathability. The question is whether the resulting rayon fibers still have any of these properties.
Most experts assume the properties would be lost as the cellulose was broken down, but there has been surprisingly little evidence either way. In 2008, Hauser told workshop attendees, "when that stalk and those fibers are dissolved to make rayon from bamboo or lyocell, that material is probably lost. I have not been able to find any documented studies in the literature where rayon or lyocell fibers have been shown to be antimicrobial just by themselves."

Gerde expressed similar misgivings. "We need to stop and consider what is the difference between the botanical entity which may convey beneficial properties, such as the antimicrobial properties, and what can convey with the cellulose from the bamboo once it has gone through commercial processing."

Research at the University of Georgia (UGA) may supply some of the answers. Ian Hardin, a professor in UGA's Department of Textiles, Merchandising and Interiors, presented his findings at AATCC's 2009 International Conference in Myrtle Beach, S.C. in March. Specimens commercially labeled as containing "bamboo" were tested for antimicrobial activity using AATCC Test Method 147. Fibers were microscopically and chemically analyzed in comparison to known bamboo and rayon fibers. Hardin's paper will be published in the October issue of AATCC Review.

Last Updated on 03 Sep 09
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