Is Tencel an Environmentally Friendly Alternative to Bamboo Fabric?

Photosource: http://www.passengerpigeon.ca

There’s never only one side to any story. Bamboo fabric is a classic example of a product that on the surface sounds very green. Bamboo plants grow incredibly quickly, can be planted in areas unsuitable for other crops, and rarely need any pesticides or herbicides. But issues arise with the way the fibres are processed and the fabric manufactured.

The most popular manufacturing process involves sodium hydroxide and carbon disulfide, both highly toxic chemicals to humans, and when released into the environment. The majority of bamboo fabric production takes place in China, a country not renowned for worker’s rights or environmental respect.

Bamboo fabric may have something to learn from another material that’s been produced quietly, with little environmental fanfare, for the last twenty years. Lyocell, sold as Tencel, is a fabric made from wood pulp. Tencel and Tencel blends drape well and are used predominantly in dresses and formalwear.

Tencel is manufactured in a proprietary process by the Lenzing Group, a international group of companies based in Austria. Lenzing describe themselves as “committed to the principles of sustainable management and very high environmental standards.” Tencel is manufactured in a similar way to bamboo fabric, but with important differences that may be the solution to green bamboo fabric manufacturing.

Here’s the recipe. First, take some wood pulp. Lenzing’s pulp mill uses hardwood – mostly birch and oak – from sustainable forestry plantations. The trees are chemically pulped and bleached. Lenzing say they utilise a closed-loop process and don’t use chlorine bleach to minimize environmental impact. However, Lenzing also buys wood pulp and their website becomes vague as to what conditions their suppliers’ wood pulp is manufactured under.

Next, the wood pulp is turned into fibres through a process called “solvent spinning”. Wood pulp is dissolved in a chemical called N-Methylmorpholine N-oxide (NMNO). The liquid is squirted through thousands of tiny holes in a spinneret, forming individual Tencel fibers. The spun fibres are washed, the NMNO is retrieved from the water, and it is purified, and reused in a 99% closed-loop process. NMNO can be toxic, but much less so than the sodium hydroxide and carbon disulfide used for processing bamboo. Small quantities of NMMO are actually produced in the body as a metabolite of several common drugs.

With a sustainable source of wood pulp, Tencel manufacturing has a much lower environmental impact than bamboo fabric. But despite considerate forestry practices, tree farms are more damaging to the ecosystem than growing bamboo. When natural forests are cleared for farms the local ecosystem suffers from the reduction in bio-diversity in the area. Bamboo is the slight winner here: it naturally colonises areas other plants find challenging and often grows with few other species for company, so it has less environmental impact when planted as a monocrop on a farm. Bamboo also grows much faster than hardwood trees, processing many times more CO2 from the environment than trees can.

Bamboo can be grown ecologically, and because of the increasing popularity of bamboo, companies are developing new, greener, ways to process the fibres ecologically, inspired by Tencel processing. Companies like Pure Bamboo are using new closed-loop processing methods, and hopefully more will follow.

Tencel is currently more eco-friendly to manufacture, and – depending on your standards – acceptably eco-friendly to grow. But bamboo fabric has the potential to be a true eco-friendly cloth.

For more on Tencel, What is Tencel on Wisegeek.

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This post was written by one of Green Cotton’s contributing writer’s Brit.

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8 Comments

  1. alex said,

    May 9, 2008 at 10:31 pm

    Hey! Thanks for all the great info. I was browsing through a bunch of green websites and blogs and I came across yours and found it very interesting. There are a bunch of others I like too, like the daily green, ecorazzi and earthlab.com. I especially like EarthLab.com’s carbon calculator (http://www.earthlab.com/signupprofile/). I find it really easy to use (it doesn’t make me feel guilty after I take it). Are there any others you would recommend? Can you drop me a link to your favorites (let me know if they are the same as mine).

  2. syansen said,

    May 12, 2008 at 1:22 am

    Dear Alex, thanks for your comment. I also like Daily Green, Ecorazzi, and Earthlab – great picks. I am also a big fan of the NY Times Fashion & Style section and Treehugger, and also read Ecosalon, Haute*Nature, Fabulously Green, Green Loop’s blog among others. I am also a huge fan of Gary Hirshberg and track his new organization Climate Counts http://www.climatecounts.org/. Speaking of carbon calculators – there are a lot out there and its interesting to compare and contrast. Another one I like is put out by the carbon fund http://www.carbonfund.org/site/pages/carbon_calculators/. Maybe that’s a good topic for a post in fact. Thank you! Cheers, Shana

  3. kaz said,

    May 23, 2008 at 10:47 am

    Hi, I’ve been looking into bamboo fabric recently, and my understanding was that the pulp is processed into bamboo fibre through a process of mixing/crushing with a low impact chemical – caustic soda. Apparently according to the WWF the carcinogenic & environmentally unfriendly chemicals used in large scale cotton production have been linked to loss of biodiversity in cotton grown regions. Like you’ve mentioned, bamboo plants themselves have numerous benefits to the environment helping eliminate nearly 5 times the greenhouse gases and producing 35% more oxygen (as a byproduct) than the equivlent strand of trees, making it an efficient way of keeping te air fresh. So given all of this, over all isn’t bamboo clothing a benefit to consumers and the environment? Thanks.

  4. kaz said,

    May 23, 2008 at 10:53 am

    Just copied this passage from a website i found. Does anyone have any comments. Thanks.
    What chemicals are used in the processing of bamboo in fibre?
    1) Bamboo leaves and the soft, inner pith from the hard bamboo trunk are extracted and crushed
    2) The crushed bamboo is soaked in sodium hydroxide. A common misconception is that sodium hydroxide is a harmful chemical. If used in a responsible manner sodium hydroxide has absolutely no effect on the environment and health of workers. It is routinely used in the processing of organic cotton into fibre and is approved by the Global Organic Textile Standards.
    3) The sodium hydroxide is removed
    4) Carbon disulfide is then added to the mixture to create viscose bamboo cellulose. There is a lot of money going into research and development to replace the carbon disulfide with more eco-friendly alternatives. N-methyl morpholine-N-oxide is non-toxic and eco-friendly and hydrogen peroxide, which is also non-toxic, may be able to be used instead.
    5) The bamboo cellulose is forced through spinneret nozzles and hardened to convert the cellulose into bamboo fibre threads
    6) The fibre threads are spun into bamboo yarn

  5. ecohannah said,

    January 1, 2009 at 3:12 pm

    Hi Kaz, Caustic Soda and Sodium Hydroxide are the same chemical! Ur right, I always thought that bamboo was an eco friendly fibre but I know that Tencel is also a good new alternative.

  6. greengirlinc said,

    June 26, 2010 at 3:09 pm

    Thank-you for this information and insight. I also have a green blog. In the past, I thought of all bamboo fabrics as eco-friendly, but now I realize it is not that simple. I’ve also been on the FTC’s website and a couple other blogs on this same subject. It seems we all, including businesses that carry bamboo fabrics, have something to learn.

  7. June 14, 2011 at 4:21 am

    For a while I’ve been wanting to find out why bamboo fibres aren’t produced using the closed-loop Lyocell (Tencel) system. Is it just a question of demanding the technology?

  8. ShirtsGoneWild said,

    June 21, 2011 at 12:14 am

    Excellent. We are selling Ahimsa silk and are producers of a farm in Croatia for manufacturing of men’s silk shirts. The bamboo line is coming to fruition and is up 300%.


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