SHADY LABELS bamboozle shoppers
It’s buyer beware when shoppers choose to go “green” by purchasing clothing items labelled as being made from bamboo, columnist Joe Schwarcz writes, because often they’re actually made from rayon.
Was I bamboozled? No. The truth is that I had bought a “bamboo” T-shirt on a Caribbean cruise not because of environmental consciousness but because I liked its silky feel. However, the Federal Trade Commission in the U.S. believes that many consumers purchase clothing items that are advertised and labelled as “bamboo” because they feel they are buying a “greener” product, based on bamboo’s quick growth and lack of requirement for pesticides. So why did the FTC send a warning letter to some retailers who were selling bamboo products? Because the items labelled and advertised as “bamboo” were actually made of rayon!
There is nothing at all wrong with rayon fibre, but there is something wrong with misleading consumers by implying that the “bamboo” item they purchased is woven from fibres stripped from the bamboo plant. This is not the case. The production of rayon requires extensive processing. A variety of plants, including bamboo, can be used as a source material to create rayon, but the final properties of the fabric do not depend on what plant was used. And no matter what the raw material, the manufacture of rayon involves the emission of air pollutants and the use of a variety of chemicals that are not exactly environmentally friendly. Still, rayon is an excellent fibre and has played a significant role in the development of textiles.
Rayon is best described as “regenerated cellulose.” Cellulose is the most abundant organic chemical in the world, being the structural component of the cell wall of green plants. In terms of molecular structure, it is composed of anywhere from several hundred to more than 10,000 glucose molecules, linked together in a linear fashion. Cellulosic fibres from the flax plant were woven into linen as early as 8,000 BC, and cotton, which has a cellulose content of more 90 per cent, was being grown, spun and woven into cloth by 3,000 BC.
Around the same time, the Chinese discovered that the cocoon formed by silkworm larvae could be unravelled and used to make very fine fabrics. Wool, matted into felt, also had its origins around this time. But all of these fibres had a downside. Cotton and linen wrinkled from wear and washings. Silk required delicate handling. Wool shrank, was itchy and served up a meal for moths. Still, until the 19th century, clothing manufacturers had to put up with such problems because there were no alternatives to the natural fibres. And then, in 1889, came the first “artificial silk,” later to be christened “rayon,” because of the fabric’s lustery, almost metallic sheen when the rays of the sun fell upon it.
Until the late 1800s, if you wanted the luxury of silk, you needed to know where to find some mulberry trees infested with silkworm pupae that had wrapped themselves in a cocoon of raw silk they exuded from their salivary glands. Boiling the cocoon killed the pupae and prevented the secretion of enzymes that would normally break down the silk in order to allow the emergence of the adult in the form of the silk moth. These enzymes degrade the silk fibre from hundreds of metres in length to shorter segments, ruining it for fabric use.
Some 5,000 cocoons are needed to make a kilo of silk, which explains why the fibre is so pricey. Although various attempts had been made throughout history to bypass the silkworm and convert mulberry leaves into silk, they all failed.
Finally, in 1889 at the Paris Exhibition, visitors got their first glimpse of a silk-like fabric that was washable like cotton, but had the lustre and delicacy of the authentic material.
Count Hilaire von Chardonnet was the inventor responsible for the marvel, which was to become the first marketable synthetic fibre. Silkworms or mulberry leaves were not involved, although the Count’s interest had been spurred by his work with Louis Pasteur on silkworm diseases. He got the idea for his artificial silk by noting that collodion, the gelatinous substance formed by dissolving nitrated cellulose in a mixture of alcohol and ether, could be extruded into a fine thread. Chardonnet’s contribution was weaving the threads into fabric. Unfortunately, Chardonnet silk had one major drawback. Like all nitrocellulose products, it was highly flammable. Workmen at the textile plants where the fabric was manufactured took to calling it “motherin-law silk.”
Around the same time, across the Channel in England, Charles Cross, Edward Bevan and Clayton Beadle were working on improving the manufacture of paper and cotton thread. The general process began by treating the cellulose-containing material with sodium hydroxide (lye) to extract the cellulose. Could other chemicals be added to produce a better product, they wondered?
Yes, as became apparent in 1892, when alkali cellulose was treated with carbon disulphide to form a bright orange grainy substance that formed a viscous solution when dissolved in water. Wasn’t of much use for making paper, but when this “viscose” was passed through tiny holes into an acid bath, it yielded a fibre that was still cellulose, but in which the long chains of glucose molecules had been broken into shorter ones. The result was a fibre that until 1924 was commonly referred to as “artificial silk.” That’s when the DuPont company began to produce this regenerated cellulose on a large scale, advertising it as “rayon.” Textile manufacturers and their customers were thrilled because rayon was half the price of raw silk.
Today, rayon is widely manufactured for clothing, sheets, blankets and upholstery because it is smooth, cool and comfortable. And that is precisely why I bought my Tshirt. In fact, I’ve ordered a couple more since. And I was gratified to find that the ones I bought bearing the Cariloha brand name would not have raised the FTC’s ire. They were clearly labelled as “made of 70% viscose from bamboo and 30% organic cotton.” No bamboozling here.