Bamboo/Rayon and how it is made

by Daniela Reiser


For a long time I was so excited about bamboo/rayon and believed it to be the best thing and eco friendly, however it really depends on how it is manufactured and in the end it may have the same environmental impact as other chemically made fabrics do. Let's look at bamboo and how it is made into fabric:

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Botanically categorized as a grass and not a tree, bamboo just might be the world’s most sustainable resource. It is the fastest growing grass and can shoot up a yard or more a day. Bamboo reaches maturity quickly and is ready for harvesting in about 4 years. Bamboo does not require replanting after harvesting because its vast root network continually sprouts new shoots which almost zoom up while you watch them, pulling in sunlight and greenhouse gases and converting them to new green growth. And bamboo does this the natural way without the need for petroleum-guzzling tractors and poisonous pesticides and fertilizers.

Bamboo the plant is wonderfully sustainable; bamboo the fabric isn’t so easy to categorize. There are two ways to process bamboo to make the plant into a fabric: mechanically or chemically. The mechanical way is by crushing the woody parts of the bamboo plant and then use natural enzymes to break the bamboo walls into a mushy mass so that the natural fibers can be mechanically combed out and spun into yarn. This is essentially the same eco-friendly manufacturing process used to produce linen fabric from flax or hemp. Bamboo fabric made from this process is sometimes called bamboo linen. Very little bamboo linen is manufactured for clothing because it is more labor intensive and costly.

Chemically manufactured bamboo fiber is a regenerated cellulose fiber similar to rayon or modal. Chemically manufactured bamboo is sometimes called bamboo rayon because of the many similarities in the way it is chemically manufactured and similarities in its feel and hand.

Most bamboo fabric that is the current eco-fashion rage is chemically manufactured by “cooking” the bamboo leaves and woody shoots in strong chemical solvents such as sodium hydroxide (NaOH – also known as caustic soda or lye) and carbon disulfide in a process also known as hydrolysis alkalization combined with multi-phase bleaching. Both sodium hydroxide and carbon disulfide have been linked to serious health problems. Breathing low levels of carbon disulfide can cause tiredness, headache and nerve damage. Carbon disulfide has been shown to cause neural disorders in workers at rayon manufacturers. Low levels of exposure to sodium hydroxide can cause irritation of the skin and eyes. Sodium hydroxide is a strong alkaline base also known as caustic soda or lye. In its dry crystalline form, caustic soda is one of the major ingredients of Drano. This is basically the same process used to make rayon from wood or cotton waste byproducts. Because of the potential health risks and damage to the environment surrounding the manufacturing facilities, textile manufacturing processes for bamboo or other regenerated fibers using hydrolysis alkalization with multi-phase bleaching are not considered sustainable or environmentally supportable.

Moving forward of course new methods are being implemented to making a more "safer" product. There is a lot of information about rayon, lyocell, TENCEL® and viscose on the internet and very interesting to read.

 

Here is a great video that explains how bamboo is made into fabric (especially from 3:50 min onwards):

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This is a very interesting article:

Good publicity or trying to make a difference

Five Bamboo, an apparel company based in Seattle, convincingly explains in an interview with REVMODO, that they have tackled the environmental challenges of bamboo and created a line of eco-friendly bamboo clothing. It is the five siblings: Zahlen, Xtehn, Vehro, Rohre and Qxhna Titcomb whom in 2008, founded the company.

earlyer, in 2005, they had a sports apparel company called Five Ultimate. But say that along the way, they realized that business could be a great vehicle for change, so the siblings spent more than two years researching bamboo fabric manufacture to find the best eco-friendly techniques. They say that their hope is that, even in a small way, they will shift the apparel industry in a more responsible direction, and educate their customers on the environmental impact of the clothes they wear on a daily basis.

„Our society needs to find a way of living that will allow us to exist and thrive within the ecological limits of our planet. So, we decided to pair our knowledge of the apparel industry with our passion for the environment to create a bamboo clothing company deeply rooted in sustainability.“58

Being aware that the majority of the bamboo apparel currently available on the market today is produced via the viscose process, which is chemically intensive and produces harmful by-products, they have their fibre manufactured using the closed-loop Lyocell process. In the interview they explain that by using this closed-loop Lyocell process no harmful chemicals are used, no harmful gases are released, and virtually no waste is created. And though the water consumption in the viscose and Lyocell processes is very similar, it doesn’t come near to the impact of growing cotton.

They call the result a NomoTM Clean Bamboo fibre.
However, ‘NomoTM Clean Bamboo’ is a trademark that they themselves have created. On there web site they explain they have there bamboo fibre made:

„ We use NomoTM Clean Bamboo fibres in our products, and the result is a line of clothing with minimal environmental impact that you'll be proud to own and wear. To make NomoTM Clean Bamboo fiber, we mix our raw bamboo pulp with a non-toxic organic solvent solution. This process of converting bamboo pulp into fiber is called the lyocell process. The organic compound NMMO isolates the cellulose, leaving us with a thick mixture which is sent through a shower head-like fixture (a spinaret) and rendered into filament form. What comes out is our NomoTM Clean Bamboo fiber. Throughout the lyocell process, the organic compound is 99% recovered and recycled or reused. [..]Once we have our NomoTM Clean Bamboo fiber, it’s ready to be spun into thread and woven into fabric. NomoTM Clean Bamboo products are made with bamboo that is processed with the most cutting edge technology in cellulosic fibres, which has a minimal impact on the environment. We oversee every step of our manufacturing process, ensuring the factories we use offer a safe working environment and fair wages, and comply with all applicable environmental laws and regulations.“

The company, Bamboosa also uses the closed-loop system, but in their process, 100% of sodium hydroxide and 74 of the carbon disulphide is recovered and recycled for further use.
In the TENCEL® production process (which is patented by the Lenzig Group) a non-toxic solvent which belongs to the amine oxide family is used. Close to 100% of the solvent is recovered in this production.
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There are no other connections to the NomoTM Clean Bamboo fibres than the company’s own statements and pr. based articles on the web.
With nothing to back up their claims of a sustainable product, it has to be questionable whether the trademark lives up to its name or is in fact false advertisement.

Concluding remarks

„The truth is rarely pure and never simple“ –Oscar Wilde.

So it turns out that being a sustainable fashion brand, is not just about choosing the right materials, it is also wise to help the consumer in the right direction, because to truly understand how “green” something is, we must look at it from “multiple lenses”: its effect on the soil, air, water, plants, animals, humans, etc.

When looking through multiple lenses at bamboo viscose based apparel production, I think it can provide a green alternative. Its amazing ecological properties at the “crop stage,” the reasonable way in which it’s produced if chosen the ‘closed-loop’ system, and the benefits that finished bamboo-based fabrics provide.

But the real task lies in sourcing the right suppliers and acquiring a good basis knowledge about the production procedure.

Today, there are no fabrics that are 100% “green;” organic and transitional cottons require large amounts of land and water; recycled P.E.T. (polyethylene terephthalate) is still a chemically driven, petroleum-based material; and many hemp and bamboo fabrics require a pulping process.62 So learning about certificate stamps, and there true meaning is valuable. The research did show that the meanings of words are being bent and misrepresented.

„Even though the manufacturing process may not be where we want it to be yet, the entire process is still usually better than most non-organic fibres and fabrics with all their chemical, synthetic and water-intensive processes in farming through manufacturing.“

Like John Thackara says in his book, „In the bubble, designing in a complex world“: „If we can design our way into difficulty we can design our way out.“64 I think bamboo could be one of the ways of designing us in the right direction towards sustainability.