PLA Fibre in Textiles: Corn on the Job
Posted on Mon, May 1st, 2006 in Articles
BY JESSICA HEMMINGS
“Humanity, nature and technology in balance,” is the clever sound bite Ingeo® uses to market the “world’s first 100% manmade fibre from annually renewable resources.” Launched by NatureWorks LLC four years ago, the Ingeo® fibre provides many of the positive characteristics of a manmade fibre such as strength and ability to wick away moisture, but is not generated from resources that are scarce or take millennia to renew themselves. “Annually renewable” is the key phrase. Corn, for example, is used. Petroleum, on the other hand, is definitely not.
Ingeo® is not the first fibre borne out of a quest for sustainability. Soy and bamboo based fibres exist and offer similar sustainability benefits. But Ingeo® has cornered the market on performance with both soy and bamboo fairing worse on performance tests for traits such as piling, wicking, drying time, appearance and shrinkage after washing. Where Ingeo® performance currently lags in its tolerance for heat. The fibre currently melts at a low temperature, ruling out ironing and limiting dye options. Steve Davies, Global Marketing Director of NatureWorks explains, “Ingeo® is an excellent drop-in for spinners and mills already set up to process polyester. This is both good news and bad. While industrial equipment designed for processes such as spinning and knitting polyester work well with Ingeo®, it also means that they have had decades of optimization around the traditional fibres. Dye stocks, for example, have long been tailored to polyester rather than Ingeo®.” Dye take up, Davies explains, of Ingeo® is different from that of polyester, which had led to misconceptions that the fibre does not dye well, when in fact it dyes differently.
Currently, some of the fibres most successful applications in fashion are when used as a base layer next to the skin (where ironing is not an issue) and combined with another fibre such as cotton used as the facing. Ironically, production of the textile industry’s newest material does not involve particularly complicated methods. The start is an abundant raw material (such as corn), which is processed to release sugars that are then fermented to produce lactic acid. Polylactide, a biodegradable thermoplastic, is derived by polymerizing this fermentation product, in this case branded under the name NatureWorks® PLA. This is then melted and extruded to produce Ingeo® fibre (in a step similar to that of many manmade fibres). Finally, the fibre itself is then turned into fabrics, which find their way into the fashion industry, bedding, carpets and even diapers.
Crucially, Ingeo®, will compost under the right conditions and allow the material cycle to come full – clean – circle. Conditions for composting aren’t quite your cuttings in the bin at the end the garden, but industrial facilities that combine both temperature and humidity trigger the PLA to lose molecular weight, which in turn allows the material to biodegrade with the help of naturally occurring microorganisms. In contrast to manmade fibres based on petroleum, the fibre is made from renewable, rather than depleting, resources. Production is also low on greenhouse emissions, which are all factors that contribute to the longevity and health of the planet.
The textile industry may be a notorious polluter, but people tend to associate this with the more visible aspects of textile production such as the water pollution from dyes used to colour cloth. Surprisingly, these more traditional methods of pollution are far outstripped by the simple creation of excessive waste, which the industry with its inexpensive, easily replaceable fabrics, comfortably provides. Not only do textiles add sheer volume to our landfills in the short term, they also stubbornly refuse to break down over time, creating large volumes of waste immune to decomposition and, in the worse case, emitting chemicals that were part of their production process. Hence, the viability of Ingeo® lies as much in its ability to break down and return to nature, as it does in its frugal use of pedestrian materials that begin its life. Davies notes that a further overlooked aspect of the textile industry is “the actual energy burden of the textiles during their life. Cotton clothing for example, holds far higher amounts of water after laundering than do the synthetics, and in a complete life cycle analysis, this shows up as higher energy usage for the drying that the modern consumer demands. By contrast, Ingeo® fabrics – as with the other synthetics, comes out of a washing machine holding very little water and dries very quickly.”
And what about during life? Forays into sustainable fibre and fabric design to date have not yielded many competitors for the luxurious materials nature creates herself. Nor have the designers interested in raising the profile of sustainability necessarily created products that are attractive to the general public. Ingeo® seems to have cracked this challenge, making appearances with high end fashion brands such as Armani and Diesel, that may begin to show the public that sustainable, ecologically-friendly materials do not mean that style needs to be compromised. Other applications include home beddings, carpets, textiles for interiors such as upholstery and drapery, as well as disposal products such as diapers and baby wipes.
Ingeo® manages to avoid petroleum, an increasingly expensive and irreplaceable resource, but for some, the fact that corn is the basis of the process is cause for concern. For consumers worried about the use of GMO (Genetically Modified Organisms) corn, NatureWorks offers three options. The first is a simple third party certification that the nature works bioplastic itself is completely GMO free. For those concerned about the agricultural use of GM seed, NatureWorks offers a ‘source offset: programme, in which downstream costumers pay the slight premium associated with offsetting the purchase of the equivalent volume of field corn associated with their fibre purchase (typical field corn in the US is a mixed stream of both conventional and GM corn), with a certified GM free corn. Davies explains that this is similar to the way in which ‘wind-power offsets work. Energy users in one part of the country may purchase wind-power “off-set” from a utility pumping wind power into the national grid on the other side of the country.
Finally, in the longer term, NatureWorks is assessing the volume and cost associated with the direct use (rather than offset) of “identity preserved” corn, which appears to be of economic interest to downstream costumers only when substantial volumes are involved. The corn is sourced from producers within a 30-mile radius of Blair, Nebraska where the NatureWorks factory is located. The factory location, in the heart of America’s “corn belt”, also helps to reduce waste and pollution caused by excessive transportation of raw materials. When the plant reaches full production capacity, it is predicted that it will use less than one half of one percent of the available American corn crop. No need to worry about interfering with the food chain too much either.
For the future? A further polymer that can withstand greater temperatures has in fact been developed, the trick is that NatureWorks current factory was not designed for the production of this newer PLA in mind. Davies confirms “it was clear from the start that there would be a demand for a higher melt-point fabric for the product to be more robust. As we introduced the first generation of the product, we began working on that next generation. We have that technology now, but plant and process modifications are required to make it.” How to introduce the new PLA at a competitive price is crucial.
Perhaps unsurprisingly, textiles are only one of the applications for the polymer NatureWorks LLC has developed. “Textiles” Davies observes, “is now a very fragmented industry. Supply chains producing for plastics end uses and markets are quite a bit simpler, which means the volume of growth is quicker because the supply chain is simpler.” Packaging materials and disposable food service wear, for example, are now areas of considerable growth within the company. Numerous food stores have adopted the material in recent years, including the French giant Monoprix, which is using NatureWorks® polymer for all salad bags, Marks & Spencer in Britain for soft fruit containers and dessert cups. Other frequently disposed items such as water bottles are also made using the polymer. London based Belu Mineral Water, for example, launched it’s ‘bio-bottle’ in 2006. “The Nebraska production site has been operating in a sold out position since late last year,” Davies offers as evidence of the boom in demand for NatureWorks® biopolymer.
With the surge in popularity the NatureWorks® PLA is enjoying, one can only hope that a little will continue to be left over for Ingeo® and the development of further manmade fibres which carry such high credentials. “We have always been interested in a broadening of applications,” Davies concludes. “Textiles is where both the short term challenges and the long term opportunities are.”
EcoTextile News (2006: 16-17)