Eucalyptus fiber by any other name

2 03 2012

Fibers are divided into three main categories:

  • Natural – like flax, wool, silk and cotton
  • Manufactured – made from cellulose or protein
  • Synthetic – made from synthetic chemicals

The difference between “manufactured” and “synthetic” fibers is that the manufactured fibers are derived from naturally-occurring cellulose or protein, while synthetic fibers are not.  And  manufactured fibers are unlike  natural fibers because they require extensive processing (or at least more than is required by natural fibers) to become the finished product.  The category of “manufactured” fibers is often called “regenerated cellulose” fibers.  Cellulose is a carbohydrate and the chief component in the walls of plants.

Rayon is the oldest manufactured fiber, having been in production since the 1880s in France, where it was originally developed as a cheap alternative to silk.   Most rayon production begins with wood pulp, though any plant material with long molecular chains is suitable.

There are several chemical and manufacturing techniques to make rayon, but the most common method is known as the viscose process. In the viscose process, cellulose is treated with caustic soda (aka: sodium hydroxide) and carbon disulfide, converting it into a gold, highly viscous  liquid about the color and consistency of honey.  This substance gives its name to the manufacturing process, called the viscose process.

The viscous fluid is allowed to age, breaking down the cellulose structures further to produce an even slurry, and is then filtered to remove impurities.  Then the mixture is forced through fine holes, called a spinerette, directly into a chemical bath where it hardens into fine strands. When washed and bleached these strands become rayon yarn.

Although the viscose process of making rayon from wood or cotton has been around for a long time, it wasn’t until 2003 that a method was devised for using bamboo for this process.(3)  Suddenly, bamboo was the darling of marketers, and the FTC had to step in to remind manufacturers to label their products as “bamboo viscose” rather than simply bamboo.

Now we hear about fabrics made from  eucalyptus, or soy.  But it’s the same story – the fibers are created using the viscose process.  Because the FTC did not specifically name these two substances in their proclamation regarding bamboo,   marketers can claim fabrics are  “made from eucalyptus”.    The reality is that the viscose process can produce fibers from any cellulose or protein source – chicken feathers, milk and even bacteria have been used (rayon comes specifically from wood or cotton).  But those inputs are not nearly as exciting to the marketers as eucalyptus or soy, so nobody has been advertising fibers made from bacteria.

After the brouhaha about bamboo viscose hit the press, many people did a quick scan of viscose and declared it “unsafe” for the environment.  The reason the viscose process is thought to be detrimental to the environment is based on the process chemicals used. Though sodium hydroxide is routinely used in the processing of organic cotton, and is approved by the Global Organic Textile Standard (GOTS), carbon disulfide can cause nervous system damage with chronic exposure.  And that “chemical bath” to harden the threads?  Sulfuric acid.  But these chemicals do not remain as a residue on the fibers – the proof of this is that almost all of the viscose produced can be (and often is) Oeko Tex certified (which certifies that the finished fiber has been tested for any chemicals which may be harmful to a person’s health and contains no trace of these chemicals.)

The environmental burden comes in disposing of these process chemicals: the sodium hydroxide (though not harmful to humans) is nevertheless harmful to the environment if dumped into our rivers as untreated effluent. Same with carbon disulfide  and, certainly, sulfuric acid.  And there are emissions of these chemicals as well, which contribute to greenhouse gasses.  And the reason that these fibers can be Oeko Tex certified:  Oeko Tex certifies only the final product, i.e.,the fibers or the fabric.  They do not look at the production process, which is where the majority of the environmental burden is found.  And then of course there is the weaving of these viscose fibers into fabric – if done conventionally, the environmental burden is devastating (in terms of chemical and water use) and the fabric itself probably contains many chemicals known to be harmful to our health.

Certainly the standard viscose production process is definitely NOT environmentally friendly, but then there is Tencel ® and Modal ®.   These fibers are manufactured by the Austrian company Lenzing, which  advertises its environmentally friendly production processes, based on closed loop systems.  Lyocell is the generic name for the fibers produced by Lenzing, which are not produced by the traditional viscose process but rather by solvent spinning.

According to Lenzing:

  • There is an almost complete recovery of the solvent, which both minimizes emissions and conserves resources.  Lenzing uses  a new non-toxic solvent (amine oxide) and the cellulose is dissolved in N-Methylmorpholine N-oxide rather than sulfuric acid. Water is also evaporated, and the resulting solution filtered and extruded as filaments through spinnerets into an aqueous bath. Over 99% of the solvent can washed from the fiber and purified for re-use. The water is also recycled.
  •  The by products of production, such as acetic acid, xylose and sodium sulphate are key ingredients in the food and glass industry. Remaining materials are used as energy for the Lenzing process.
  • Tencel ® is made from eucalyptus, which is grown on marginal land unsuitable for food crops; these trees are grown with a minimum of water and are grown using sustainable forestry initiatives.
  • The final fibers are biodegradable and can decompose in soil burial or in waste water treatment plants.

So Lenzing fibers can be considered a good choice if you’re looking for a sustainable fiber – in fact there is a movement to have Lenzing Tencel® eligible for GOTS certification, which we support, because the production of these fibers conforms with the spirit of GOTS.  They already have the EU Flower certification.

But Lenzing does not make fabrics – it sells yarns to mills and others which use the yarns to make fabric and other goods.

So  we’re back to the beginning again, because people totally forget about the environmental impact in the weaving of fibers into fabric, where the water and chemical use is very high –  if done conventionally, the environmental burden is devastating  and the finished fabric itself probably contains many chemicals which are outlawed in other products.

It’s critically important to look at both the fiber as well as the weaving in order to make a good choice.



22 responses

3 03 2012

I have read one definition of soy fiber as being produced from the waste or biproduct of making tofu (like casin) and other descriptions of the use of the plant stem and leaves in the viscose process.

5 03 2012
O Ecotextiles

Thanks for your comment. As far as I can tell, soy fibers are produced from “okara” (soy pulp), a by-product of tofu production -it is the insoluble part of soybean that remains when pureed soybeans are filtered in the production of soy milk or tofu. The protein is separated from the pulp and spun into fiber – similar to the milk protein casein. Soy straw is not used as often – though it can be suitable for textiles – but is used rather as a source of biofibers to be used in combination with plastics for biocomposites.
It’s interesting to note that soybean fiber has been around for a while: it was invented by Henry Ford in 1937; he called it soy “wool”. Henry Ford also made a suit and necktie from soybean fiber and used this unique fiber in car upholstery. Soybean was being manufactured in Poland until the 60’s. The new soybean fiber (which is a by product of food production) was invented in 1998. It is controversial since most soybean from the US is GMO, though this is not the case for European soybeans

18 10 2012

Can you explain more about superwash that is Oekotex certified that also has woolmark? After all the processing, is it still really 100%wool?or is it wool coated with a polymer?is the coating something that does not wash off ? What exactly does it mean for oekotex to certify it as 100%wool if it is really not?

18 10 2012
O Ecotextiles

“Superwash” means basically that the scales from the wool fibers have been removed so that the wool doesn’t felt when washed. And that can be done by using enzymes, ozone or a chlorination process – or by coating the fibers with a polymer (which does not wash off) called polyamide-epichlorohydrin, which is also used in the paper industry and in the production of glycerin and epoxy resins. And there is no requirement that consumers be told which process is used. I don’t know which fabric you’re referring to, though usually Oeko Tex certifies only that the fabric is safe for human use. So if the fabric is shown to have chemicals below the Oeko Tex threshhold limit values, then it can be certified. I don’t believe Oeko Tex can certify a fabric as being 100% wool, that must be a claim made by the manufacturer, since Oeko Tex doesn’t care what the fiber content is as long as the chemicals contained in the fabric are below the limit values. But Oeko Tex certification doesn’t look at the production of the fabric, and it should be noted that the superwash process, whether it be a resin (polymer) or chlorination, creates considerable toxic byproducts.

21 10 2012

I am referring to wool duvets sold by “The Wool Company” in the UK . Would the manufacturer be where its made, in China? I am unable to reach them because The Wool Company is ignoring my questions, saying they do not know and that I should be able find the answers to my questions online and on Oeko texs website. I want to know why they can sell a blanket saying “100% pure new wool”, when it is not, it is coated with a polymer/resin making that, in my opinionopinion, false advertising. Do i have this right?

22 10 2012
O Ecotextiles

I don’t know how the wool used in The Wool Company’s duvets is superwashed; to give them the benefit of the doubt they could have used enzymes. And remember, Oeko Tex is just certifying that there is nothing in the finished product which will harm human health – they pay no attention to what its made of or how it was made, so it doesn’t matter if its 100% wool or 95% wool and 5% resin. But it does seem to me that a claim of 100% pure new wool, IF it is coated with a resin, is misleading.

1 11 2012

Do you mean if its washed with enzymes that it may not have a resin/residue? It can be washed and dryed in the dryer (!) Based on that alone i think it is not very wool like. So, no matter how its superwashed it isnt going to be a 100% all wool product , right? Because the superwashing is what does the damage? I understand oekotex certifies it to be not as bad as other synthetic but its still bad if your body cant breathe when exposed to them, which is what this does? If it were 5%resin, is the resin like a coating completely sealing in the wool, making it “feel like” 100% resin/synthetic?

4 11 2012

Thank you again for your through explanations. I really appreciate it. I find this all so confusing and let me know if my questions dont make sense to you. I look forward to your response. Take care.

4 11 2012
O Ecotextiles

You’re getting into an area I’m not familiar with since we don’t use superwashed wool (which by the way is a patented process); I’ll try to give you my opinion. Superwashed wool is wool that does not felt, which means the scales from the wool fibers have been either removed, or coated. If the fibers are coated, you’ve got the addition of the resin coating as a component of the fibers. I don’t understand why you say that the removal of the scales results in a less than 100% wood product – if that were true, then chemical treatment of all fibers would mean that we do not ever use a fabric made of 100% of any fiber, since all fibers are subjected to a great deal of chemical processing. If the wool is 5% resin, I would think that the company should say 95% wool, 5% superwash (or whatever). The superwashed wool I have felt has not had a resin/synthetic feel, nor is the claim that the wool fibers lose their breatheability. Think of superwashed wool socks – it would be disastrous if the socks didn’t breathe!

24 01 2014
Textile Aid

Most cellulose fibers used wood and cotton linters. Wood is the universal cellulose material. Rayon was the first cellulose regenerated fiber made from cotton linters and wood pulp through wet spinning.

11 02 2014
John Kelly

Very little thought is given to the care and maintenence of these products.These natural fibres are generally uncleanable. Certainly as upholstery fabric or carpets they are not wet cleanable so have to be “dry cleaned” using a granular product such as solvent soaked corn husk, surface cleaned only and often poor results or, in the case of upholstery fabrics have to cleaned with mineral solvents. Grass type flooring such as Sisal is not fit for purpose as it is impossible to clean effectively.
Traditional fibres such as Cotton or Wool and manmade plastics can be safely cleaned using eco friendly detergents and water.

16 02 2014
O Ecotextiles

Hi John: It’s not clear to me which fibers you say are generally unclean able. Could you please clarify?

Leigh Anne

25 03 2014

I have been trying to get to the bottom of the compostability/biodegradability of viscose process fibers such as rayon and bamboo. Many articles I’ve read say they will biodegrade or break down, but it is unclear what they break down into. Does this mean that they break apart into tiny particles of wood or bamboo that are once again completely innocuous to the earth? Or do they breakdown into tiny particles of something that was once wood or bamboo but has been forever altered by chemicals into another form? I do understand that either way the process of turning them into a textile involves toxic chemicals.
Thank you,

26 03 2014
O Ecotextiles

You’re correct that toxic chemicals must be used to create the viscose fibers, so it’s important to know if the producer treats his wastewater and captures the outgassing which occurs at some of the stages of production. According to the Lenzing website (maker of a wide variety of viscose fibers and a respected leader in environmental stewardship), viscose, made of cellulose, is both compostable and biodegradable, breaking down into water and CO2 – both of which are available to plants and enabling the cycle to continue.

1 04 2014

Thank you, thank you! This is very helpful!

25 04 2016

I am confused about why you say the weaving process produces an ecological burden. I am a weaver and the process does produce lint in my house. But when I wet finish my fabric, I am simply washing it in the same manner that the item will be cleaned in the future.

Are you referring to the dyeing of the fiber, yarn or fabric rather than the mechanical process of weaving or knitting the fabric? Of course, there are the sizing and finishing steps in some weaving plants for producing fabric which is wrinkle free – maybe that is what you mean?


27 04 2016
O Ecotextiles

Most fabrics are finished in what is called “wet processing” where the finish is applied in a liquid – which accomplishes some sort of chemical action to the textile – as opposed to “dry processing”, which is a mechanical/physical treatment, such as brushing. It is a series of innumerable steps leading to the finished textile, each one of which also has a complex number of variables, in which a special chemical product is applied, impregnated or soaked with the textile fiber of the fabric. A defined sequence of treatments can then be followed by another sequence of treatments using another chemical substance. Typically, treatments are arranged to permit a continuous mode of sequences.

The 2010 AATCC (American Association of Textile Chemists and Colorists) Buyer’s Guide lists about 2,000 chemical specialties in over 100 categories offered for sale by about 66 companies, not including dyes. The types of products offered run the gamut from antimicrobial agents and binders to UV stabilizers and wetting agents.

In addition to the branded products supplied by chemical companies, which are made of unknown components because they’re proprietary, we know many chemicals are necessary to achieve certain effects, such as PBDEs for fire retardants, formaldehyde resins for crease resistance or PFOA’s for stain protection – all of them very harmful to humans.

The chemicals used in these branded products to create the effects above include chemicals which have been proven to be toxic, or to cause cancers or genetic mutations in mammals (i.e., us too). The following is by no means an all-inclusive list of these chemicals:
• Alkylphenolethoxylates (APEOs)
• Pentachlorophenols (PCP)
• Toluene and other aromatic amines
• Dichloromethane (DCM)
• Formaldehyde
• Phthalates
• Polybrominated diphenyl ethers ( PBDE’s)
• Perfluorooctane sulfonates (PFOS)
• Heavy metals – copper, cadmium, lead, antimony, mercury among others

The 40,000 to 50,000 tons of ynthetic dyestuffs expelled into our rivers are complex chemical formulations containing some things that are very toxic to us, such as heavy metals (like lead, mercury, chromium, zinc, cobalt and copper), benzene and formaldehyde. Many certifications, such as the new Global Organic Textile Standard and Oeko-Tex, restricts the kinds of chemicals allowed in certified products. So the dye formulation means a lot when you’re evaluating the eco credentials of a fabric – but almost never will you be able to find out what dye was used in any particular fabric.

Remember that if the average exhaustion rate is 80% for most dyes (i.e., that 20% of the dyestuff is expelled with the wastewater) then that means that 80% of the dyestuff remains in the fabric or yarn! In other words, those toxic chemicals remain in the fabrics you bring into your homes. What do I mean by “toxic” – if you can stand it, I’ll give a short synopsis of the effects some of these chemicals found in many dyestuffs and used in textile processing have on us:
• Mercury: Easily absorbed thru the skin or inhalation of dust which contains residues; effects the immune system, alters genetic and enzyme systems, damages the nervous system. Particularly damaging to developing embryos, which are 5 to 10 times more sensitive than adults.
• Lead: Easily absorbed thru the skin or inhalation of dust which contains residues. Impacts nervous system. Even low levels of lead can reduce IQ, stunt growth and cause behavior problems.
• Chromium: Necessary for insulin activity and an essential trace metal; at toxic levels it causes squamous cell carcinoma of the lung.
• Copper: Fatigue, insomnia, osteoporosis, heart disease, cancer, migraine headaches, seizures. Mental disorders include depression, anxiety, mood swings, phobias, panic attacks and attention deficit disorders.
• Cadmium: Extremely toxic to humans because of its inhibition of various enzyme systems; primary target organ is the kidney; but also causes lung cancer ; also causes testicular damage and male sterility. Plants readily absorb cadmium from the soil so it easily enters food chain. Chronic exposure is associated with renal disease.
• Sodium chloride (salt): not toxic in small doses (thankfully for me and my salt addiction), but the industry uses this in such high volumes it becomes an environmental hazard; an organochlorine (the class of organochlorines are very stable (i.e. does not break down into other compounds) and they bioaccumulate; 177 different organochlorines have been found in the average population in Canada and the US. Each person has a unique level at which this build-up becomes critical and triggers a wide range of health problems.) Well known effects of chronic organochlorine contamination include hormonal disruption, infertility and lowered sperm counts, immune system suppression, learning disabilities, behavioral changes, and damage to the skin, liver and kidneys. Newborns, infants, children, childbearing women and the elderly are even more vulnerable to these health impacts.
• Toluene: affects the central nervous system; symptoms range from slight drowsiness, fatigue and headaches, to irritation of the respiratory tract, mental confusion and incoordination; higher concentrations can result in unconsciousness and death. Prolonged contact can cause dermatitis. Teratogenic, embryotoxic.
• Benzene: Highly carcinogenic, linked to all types of leukemia but believed to cause the rarer forms (acute myelogenous leukemis (AML) and acute lymphocytic leukemia (ALL); effects the bone marrow and decrease of red blood cells, leading to anemia, excessive bleeding and/or immune system disfunction. Low levels cause rapid heart rate, dizziness, headaches, tremors, confusion. Easily absorbed by the skin.

Since you say you weave in your house, I would not consider your fabric to be similar in any way to the industrial textile mills that produce millions of yards of fabric per year. But I would look into the dyestuffs you use to make sure the yarns don’t contain the heavy metals that are found in so many textile dyes.

27 04 2016

Incredible amount of information – thank you so much for taking the time, that is my understanding of processing after weaving. I am also worried by the current artistic fad of “dyeing” cloth with iron water. I don’t want to wear cloth that has been boiled with rusty metal. Do you have any references on that – on either side of the story – that I could pass on to folks I know who are enamored of the process?

27 04 2016
O Ecotextiles

I had never heard of that, but I googled it and found that this process is very old, dating back to the Swiss Lake Dwellers (3000 BC). The most commonly used “iron water” chemical is ferrous sulfate – which is the active ingredient in SlowFe, a tablet used to treat anemia (which I take occasionally as I have borderline anemia). I tried to find information about toxicity of ferrous sulfate, and it seems the general consensus is to keep it in a safe place, because overdoses of products containing iron are the leading cause of poisoning in children under 6.

27 04 2016

Thanks again. I’ll have to search to see if iron is absorbed through the skin. To see what kind of printing I’m talking about, you can google for eco-printing with iron water.

3 01 2020
Dr. Sigrid Fry-Revere

Should I be worried that my “100% Premium Tencel” sheets were made in China? Distributed by DTY from Colorado, USA

16 06 2020
O Ecotextiles

I’m afraid that the answer is yes. Why? Because Tencel is the brand name of a fiber. Tencel is a great choice BUT choosing a fiber is only step one of the production process. The Tencel was spun into yarn, then woven and finished by somebody (many many somebodies as each step can be done by a different business); and then the finished fabric was cut and sewn. Anyway, if the FINAL PRODUCT is not certified by Oeko-Tex then there is a good chance that it is full of chemicals that you do not want to be sleeping on. But check and see if your sheets are Oeko-Tex 100 certified. They might be.

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