What does “mercerized” cotton mean?

5 12 2012

fullsizeMercerization is a process applied to cellulosic  fibers  – typically cotton (or cotton-covered thread with a polyester core)  but hemp and linen can be mercerized also – to increase luster.  It is done after weaving (in the case of fabrics) or spinning (for yarns or threads).  But early on it was found that the process also had secondary benefits:  the mercerized fibers were able to absorb more water, and therefore absorb more dye, making the color of the dyed cloth brighter and deeper.  The difference is dramatic:  mercerization increases the absorption of dyestuffs by as much as 25%.[1]  unmercerized-101mercerized-101Not only is the color brighter, it also gives the cloth a better resistance to multiple washings,  keeping the colors bright and unchanged over time.   In addition to increasing luster and affinity to dyestuffs, the  treatment increases strength, smoothness, resistance to mildew, and also reduces lint.  So higher quality yarns and fabrics,  for example, are always mercerized.

The process goes back to the 1880’s.   John Mercer was granted a British Patent for his discovery that cotton and other fibers changed character when subjected to caustic soda (NaOh, also known as sodium hydroxide or lye), sulfuric acid, and/or other chemicals.   One of the changes was that caustic soda caused the fiber to swell, become round and straighten out.  But so what – these changes didn’t impart any luster to the fibers, so his patent was largely ignored.  Then in 1890 Horace Lowe found that by applying Mercer’s caustic soda process to cotton yarn or fabric under tension, the fabric gained a  high luster  as a result of the light reflection off the smooth, round surface created by the NaOH. It became an overnight success and revolutionized the cotton industry. The rest is history.[2]

Later testing proved that cotton fiber in its roving state (no twist in the yarns) would absorb more NaOH than fiber in a twisted state and as a result would absorb more water or dye.  Since fine, long stapled fiber gives the best absorption with the lowest twist, ( some twist is required for treating under tension to gain luster) it is usually the long fiber types of cotton (Sea Island, Egyptian, Pima) that are selected for yarn to be mercerized.   So mercerized cotton fabric starts with a better quality cotton fiber.

How is it done?

To get the desired luster and tensile strength,  cotton is held under specified tension for about ten minutes with an application of between 21%-23% caustic soda (NaOH) and wetting agents (used to facilitate the transfer of the NaOH into the fibers), at room temperature.  Then the fabric is neutralized in an acid bath.

Luster is a result of light reflection off a surface. The more glass like the surface, the better the luster. Yarn in its spun, treated state still has a very fine covering of tiny fiber ends (fuzz). This fuzz is removed by passing the yarn (or fabric) through a controlled heated atmosphere termed singeing (gas fired in the past, electric more currently) resulting in a cleaner surface.  (Luster is a result of light reflection off a surface. The more glass like the surface, the better the luster.)
You knew I’d have to look at the toxicity profile of sodium hydroxide, which is considered one of the building blocks of chemistry.  It’s a very powerful alkali.   It’s used in industry in a broad range of categories: chemical manufacturing; pulp and paper manufacturing; cleaning products such as drains, pipe lines and oven cleaners ; petroleum and natural gas; cellulose film;  and water treatment as well as textiles. The US Food and Drug Administration (FDA) considers sodium hydroxide to be generally safe, and recognizes it as not being found to pose unacceptable dietary risks, though it is generally only used on food contact surfaces rather than in foodstuffs.

The chemical is toxic to wildlife, and the EPA requires that effluent containing NaOH not be discharged into groundwater.  Because sodium hydroxide falls in the group of chemicals (salts) which are by far the most often used in textile processing, the sheer volume of NaOH used by the textile industry is important to recognize.  Usual salt concentrations in cotton mill wastewater can be 2,000 – 3,000 ppm[3], far in excess of Federal guidelines for in-stream salt concentrations of 230 ppm.  So treatment of effluent is very important, as prevention is the only reasonable alternative to solve the environmental problems associated with this hard-to-treat, high volume waste.  I have read that electrochemical cell treatment might be a substitute for using NaOH to mercerize.  This process occurs in a low voltage electrochemical cell that mercerizes, sours, and optionally bleaches without effluents and without the purchase of bulk caustic, neutralizing acids, or bleaches.





How to buy a quality sofa – part 4: synthetic fibers

3 10 2012

So from last week’s post, you  know that you want a durable, colorfast fabric that will be lovely to look at and wonderful to live with.  What’s the best choice?  I’m so glad you asked.

You have basically two choices in fibers:  natural (cotton, linen, wool, hemp, silk)  or synthetic (polyester, acrylic, nylon, etc.).  Many fabrics today are made from blends of natural and synthetic fibers – it has been said that most sheet sets sold in the U.S. are cotton/poly blends.

Natural fibres breathe, wicking moisture from the skin, providing even warmth and body temperature;  they are renewable, and decay at end of life.  On the other hand, synthetics do not breathe,  trapping body heat and perspiration; they are based on crude oil, definitely a non-renewable resource and they do not decompose at end of life, but rather remain in our landfills, leaching their toxic monomers into our groundwater.  They are, however, cheap and durable.

I like to think that even without the health issues involved I’d choose to live with natural fibers, since they work so well with humans!  The fibers themselves present no health issues and they’re comfortable.  But they simply don’t last as long as synthetics. But I have begun to see the durability of synthetics as their Dorian Grey aspect, in other words they last so long that they’ve become a huge problem.  By not decomposing, they just break into smaller and smaller particles which leach their toxic monomers into our groundwater.

The impact on health (ours the the planet’s) is an issue that’s often overlooked when discussing the merits of natural vs. synthetic.   And it’s a complex issue, so this week we’ll explore synthetic fibers, and next week we’ll look at natural fibers.

The most popular synthetic fiber in use today is polyester.

At this point, I think it would be good to have a basic primer on polyester production, and I’ve unabashedly lifted a great discussion from Marc Pehkonen and Lori Taylor, writing in their website diaperpin.com:

Basic polymer chemistry isn’t too complicated, but for most people the manufacture of the plastics that surround us is a mystery, which no doubt suits the chemical producers very well. A working knowledge of the principles involved here will make us more informed users.

Polyester is only one compound in a class of petroleum-derived substances known as polymers. Thus, polyester (in common with most polymers) begins its life in our time as crude oil. Crude oil is a cocktail of components that can be separated by industrial distillation. Gasoline is one of these components, and the precursors of polymers such as polyethylene are also present.

Polymers are made by chemically reacting a lot of little molecules together to make one long molecule, like a string of beads. The little molecules are called monomers and the long molecules are called polymers.

Like this:

O + O + O + . . . makes OOOOOOOOOOOOOOOO

Depending on which polymer is required, different monomers are chosen. Ethylene, the monomer for polyethylene, is obtained directly from the distillation of crude oil; other monomers have to be synthesized from more complex petroleum derivatives, and the path to these monomers can be several steps long. The path for polyester, which is made by reacting ethylene glycol and terephthalic acid, is shown below. Key properties of the intermediate materials are also shown.

The polymers themselves are theoretically quite unreactive and therefore not particularly harmful, but this is most certainly not true of the monomers. Chemical companies usually make a big deal of how stable and unreactive the polymers are, but that’s not what we should be interested in. We need to ask, what about the monomers? How unreactive are they?

We need to ask these questions because a small proportion of the monomer will never be converted into polymer. It just gets trapped in between the polymer chains, like peas in spaghetti. Over time this unreacted monomer can escape, either by off-gassing into the atmosphere if the initial monomers were volatile, or by dissolving into water if the monomers were soluble. Because these monomers are so toxic, it takes very small quantities to be harmful to humans, so it is important to know about the monomers before you put the polymers next to your skin or in your home. Since your skin is usually moist, any water-borne monomers will find an easy route into your body.

Polyester is the terminal product in a chain of very reactive and toxic precursors. Most are carcinogens; all are poisonous. And even if none of these chemicals remain entrapped in the final polyester structure (which they most likely do), the manufacturing process requires workers and our environment to be exposed to some or all of the chemicals shown in the flowchart above. There is no doubt that the manufacture of polyester is an environmental and public health burden that we would be better off without.

What does all of that mean in terms of our health?  Just by looking at one type of cancer, we can see how our lives are being changed by plastic use:

  • The connection between plastic and breast cancer was first discovered in 1987 at Tufts Medical School in Boston by research scientists Dr. Ana Soto and Dr. Carlos Sonnenschein. In the midst of their experiments on cancer cell growth, endocrine-disrupting chemicals leached from plastic test tubes into the researcher’s laboratory experiment, causing a rampant proliferation of breast cancer cells. Their findings were published in Environmental Health Perspectives (1991)[1].
  • Spanish researchers, Fatima and Nicolas Olea, tested metal food cans that were lined with plastic. The cans were also found to be leaching hormone disrupting chemicals in 50% of the cans tested. The levels of contamination were twenty-seven times more than the amount a Stanford team reported was enough to make breast cancer cells proliferate. Reportedly, 85% of the food cans in the United States are lined with plastic. The Oleas reported their findings in Environmental Health Perspectives (1995).[2]
  • Commentary published in Environmental Health Perspectives in April 2010 suggested that PET might yield endocrine disruptors under conditions of common use and recommended research on this topic. [3]

These studies support claims that plastics are simply not good for us – prior to 1940, breast cancer was relatively rare; today it affects 1 in 11 women.  We’re not saying that plastics alone are responsible for this increase, but to think that they don’t contribute to it is, we think, willful denial.  After all, gravity existed before Newton’s father planted the apple tree and the world was just as round before Columbus was born.

Polyester fabric is soft, smooth, supple – yet still a plastic.  It contributes to our body burden in ways that we are just beginning to understand.  And because polyester is highly flammable, it is often treated with a flame retardant, increasing the toxic load.  So if you think that you’ve lived this long being exposed to these chemicals and haven’t had a problem, remember that the human body can only withstand so much toxic load – and that the endocrine disrupting chemicals which don’t seem to bother you may be affecting generations to come.

And then there is acrylic.  The key ingredient of acrylic fiber is acrylonitrile, (also called vinyl cyanide). It is a carcinogen (brain, lung and bowel cancers) and a mutagen, targeting the central nervous system.  According to the Centers for Disease Control and Prevention, acrylonitrile enters our bodies through skin absorption, as well as inhalation and ingestion.  So could the acrylic fibers in our acrylic fabrics be a contributing factor to these results?

Acrylic fibers are just not terrific to live with anyway.  Acrylic manufacturing involves highly toxic substances which require careful storage, handling, and disposal. The polymerization process can result in an explosion if not monitored properly. It also produces toxic fumes. Recent legislation requires that the polymerization process be carried out in a closed environment and that the fumes be cleaned, captured, or otherwise neutralized before discharge to the atmosphere.(4)

Acrylic is not easily recycled nor is it readily biodegradable. Some acrylic plastics are highly flammable and must be protected from sources of combustion.

Just in case you missed the recent report which was published in Occupational and Environmental Medicine [5], a Canadian study found that women who work with some common synthetic materials could treble their risk of developing breast cancer after menopause. The data included women working in textile factories which produce acrylic fabrics – those women have seven times the risk of developing breast cancer than the normal population, while those working with nylon fibers had double the risk.

What about nylon?  Well, in a nutshell, the production of nylon includes the precursors benzene (a known human carcinogen) and hydrogen cyanide gas (extremely poisonous); the manufacturing process releases VOCs, nitrogen oxides and ammonia.  And finally there is the addition of those organophosphate flame retardants and dyes.

[1] http://www.bu-eh.org/uploads/Main/Soto%20EDs%20as%20Carcinogens.pdf

[2] http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info:doi/10.1289/ehp.95103608

[3] Sax, Leonard, “Polyethylene Terephthalate may Yield Endocrine Disruptors”,
Environmental Health Perspectives, April 2010, 118 (4): 445-448

(4) ) http://www.madehow.com/Volume-2/Acrylic-Plastic.html

(5) Occupational and Environmental Medicine 2010, 67:263-269 doi: 10.1136/oem.2009.049817 (abstract: http://oem.bmj.com/content/67/4/263.abstract) SEE ALSO: http://www.breastcancer.org/risk/new_research/20100401b.jsp AND http://www.medpagetoday.com/Oncology/BreastCancer/19321





Listmania: LBC Red List and others

19 06 2012

I love lists – you know, all those “best of” lists – movies, books, toxic chemicals.

Having a list makes it easy for us to tick off those bad chemicals that nobody wants to live with.  And in the building industry there have been a proliferation of lists which identify chemicals of concern:  the Perkins & Will Precautionary List, the LEED Pilot 11 and the Living Building Challenge Red List, among others.  And make no mistake, we think it’s critical that we begin to develop these lists, because we all need a baseline.   As long as we need to eat and breathe, toxics should be an important consideration.  We just have a problem with  how these lists are used.

So let me explain.

First, lists for the most part are developed on the basis of science that usually occurred five or 10 years ago, so they can  (though not always) be lagging indicators of safety to humans and the environment.  (But that’s a minor point, just wanted us to remember to maintain those lists.)

When using lists, it’s important to remember the concept of reactive chemistry:  many of the chemicals, though possibly deemed to be benign themselves, will react with other chemicals to create a third substance which is toxic.   This reaction can occur during the production of inputs, during the manufacture of the final product, or at the end of life (burning at the landfill, decomposing or biodegrading).   So isn’t it important to know the manufacturing supply chain and the composition of all the products – even those which do not contain any chemicals of concern on the list you’re using – to make sure there are no, say … dioxins created during the burning of the product at the landfill, for example?

It’s also important to remember that  chemicals are synergistic  – toxins can make each other more toxic.  A small dose of mercury that kills 1 in 100 rats and a dose of aluminum that will kill 1 in 100 rats, when combined, have a striking effect: all the rats die.  So if the product you’re evaluating is to be used in a way that introduces a chemical which might react with those in your product, shouldn’t that be taken into consideration?

So, O.K., the two problems above would be extremely difficult to define  – I mean, wouldn’t you need a degree in chemistry, not to mention the time and money, to determine if these could occur .  The average consumer wouldn’t have a clue.  Just wanted you to know that these problems do exist and contribute to our precautionary admonition regarding lists.

Each list has a slightly different interpretation – and lists different chemicals.  The Healthy Building Network published this Venn diagram of several of the most prevalent lists used in building materials:

The real reason we don’t like the way lists are used is that people see the list, are convinced by a manufacturer that their product doesn’t contain any of the chemicals listed, so without any further ado the product is used.

What does that mean in the textile industry, for example?

By attempting to address all product types, most lists do not mention many of the toxic chemicals which ARE used in textile processing. In the Living Building Challenge Red List, no mention is made of polyester, the most popular fiber for interiors, which itself is made from two toxic ingredients (ethylene glycol and terephthalic acid – both carcinogens, neither of which are on the list).  That means  a fabric made of polyester – even recycled polyester – that has been processed using some pretty nasty chemicals – could be specified.   Chemicals which are commonly used in textile processing  and which are NOT included on the Living Building Challenge Red List, for example,  but which have been found to be harmful , include:

Chlorine   (sodium hypochlorite NaOCL); registered in the Toxic Substances Control Act   as hypochlorous acid ; sodium chlorite
Sodium cyanide;   potassium cyanide
sodium sulfate   (Na2SO4)
Sodium sulfide
 APEOs ( Alkylphenolethoxylates)
Chromium III   and VI (hexavalent chromium)
Zinc
Copper
pentachlorophenol   (PCP)
permethrin
Dichloromethane   (DCM, methylene chloride)
Tetrachloroethylene   (also known as perchloroethylene, perc and PCE)
Methyl ethyl   ketone
Toluene:   toluene diisocyanate and other aromatic amines
Methanol (wood   alcohol)
Chloroform;   methyl chloroform
Arsenic
Phosphates   (concentrated phosphoric acid)
Dioxin –   by-product of chlorine bleaching; also formed during synthesis of certain   textile chemicals
Benzenes and   benzidines; nitrobenzene; C3 alkyl benzenes; C4 alkyl benzenes
Sulfuric Acid
Optical   brighteners: includes several hundred substances, including triazinyl   flavonates; distyrylbiphenyl sulfonate
Acrylonitrile
ethylenediaminetetra   acetic acid [EDTA]
diethylenetriaminepenta   acetic acid [DTPA]
Perfluorooctane   sulfonates (PFOS)

In the case of arsenic (used in textile printing and in pesticides) and pentachlorophenol (used as a biocide in textile processing) – the Living Building Challenge Red List expressly forbids use in wood treatments only, so using it in a textile would qualify as O.K.

Perhaps we should manufacture with a “green list” in mind: substituting chemicals and materials that are inherently safer, ideally with a long history of use (so as to not introduce completely new hazards)?

But using any list of chemicals of concern ignores what we consider to be the most important aspect needing amelioration in textile processing – that of water treatment.  Because the chemicals used by the textile industry include many that are persistent and/or bioaccumulative which can interfere with hormone systems in people and animals and may be carcinogenic and reprotoxic, and because the industry often ignores water treatment even when it is required (chasing the lowest cost) the cost of dumping untreated effluent into our water is incalculable.

The textile industry uses a LOT of water – according to the World Bank, 20% of industrial freshwater pollution is from the textile industry; that’s another way of saying that it’s the #1 industrial polluter of water on the planet.  In India alone textile effluent averages around 425,000,000 gallons per day, largely untreated[1].   The chemically infused effluent – saturated with dyes, de-foamers, detergents, bleaches, optical brighteners, equalizers and many other chemicals –  is often released into the local river, where it enters the groundwater, drinking water, the habitat of flora and fauna, and our food chain.  The production of polychlorinated biphenyls (PCBs) were banned in USA more than 30 years ago (maybe that’s why they’re not listed on any of these lists?), but are still showing up in the environment as unintended byproducts of  the chlorination of wastes in sewage disposal plants that have a large input of biphenyls (used as a dye carrier) from textile effluent.[2]

Please click HERE to see the PDF by Greenpeace on their new campaign on textile effluent entitled  “Dirty Laundry”, which points the finger at compliant corporations which basically support what they call the “broken system”.  It asks corporations to become champions for a post toxic world, by putting in place policies to eliminate the use and release of all hazardous chemicals across a textile company’s entire supply chain based on a precautionary approach to chemicals management, to include the whole product lifecycle and releases from all pathways.

Another problem in the textile industry which is often overlooked is that of end of life disposal.  Textile waste in the UK, as reported by The Ecologist, has risen from 7% of all waste sent to landfills to 30% in 2010.[3]  The US EPA estimates that textile waste account for 5% of all landfill waste in the U.S.[4]  And that waste slowly seeps chemicals into our groundwater, producing environmental burdens for future generations.  Textile sludge is often composted, but if untreated,  that compost is toxic for plants.[5]

What about burning:    In the United States, over 40 million pounds of still bottom sludge from the production of ethylene glycol (one of the components of PET fibers) is generated each year. When incinerated, the sludge produces 800,000 lbs of fly ash containing antimony, arsenic and other metals.[6]

These considerations are often neglected in looking at environmental pollution by textile mills[7] – but is never a consideration on a list of chemicals of concern.

So yes, let’s recognize that there are chemicals which need to be identified as being bad, but let’s also look at each product and make some kind of attempt to address any other areas of concern which the manufacture of that product might raise.  Using a list doesn’t get us off the hook.


[1] CSE study on pollution of Bandi river by textile industries in Pali town, Centre for Science and Environment,New Delhi, May 2006 and “Socio-Economic, Environmental and Clean Technology Aspects of Textile Industries in Tiruppur,South India”, Prakash Nelliyat, Madras School of Economics.  See also:

Jacks Gunnar et al (1995), “The Environmental Cost of T-Shirts”, Sharing Common Water Resources, First Policy Advisory Committee Meeting, SIDA, Madras Institute of Development Studies, Chennai.

Also:  CSE: Down to Earth Supplement on Water use inIndia, “To use or to misuse”;  http://www.cseindia.org/dte-supplement/industry20040215/misuse.htm

[3] Ecologist, “’Primark effect’ sill clogging up UK landfills”, January 19, 2010,  http://www.newsinferno.com/legal-news/possible-link-between-formaldehyde-lou-gehrigs-disease-found/2926

[5] Scientia Agricola, vol. 62, no 3 May/June 2005

[6] Sustainable Textile Development at Victor,  http://www.victor-innovatex.com/doc/sustainability.pdf

[7] Assuming a beginning value of 375ppm of antimony in an undyed polyester fiber, as much as 175ppm of antimony can be leached from the fiber during the dyeing process. This seemingly insignificant amount translates into a burden on water treatment facilities and is still a hazardous waste when precipitated out during treatment. The U.S. EPA lists the allowable limit for antimony in drinking water to be 6 parts per billion (ppb). Countries that can afford technologies that precipitate the metals out of the water are left with a hazardous sludge that must then be disposed of in a properly managed landfill or incinerator operations. Countries who cannot, or who are unwilling to employ these end-of-pipe treatments, release antimony along with a host of other dangerous substances to open waters. Victor Defining Sustainability, http://www.victor-innovatex.com/doc/sustainability.pdf





What about chrome-free, or “eco” leather?

29 05 2012

With the increased interest in avoidance of certain chemicals and industrial products that are particularly harmful to our environment, it’s not surprising that manufacturers are becoming ingenious in pointing out attributes that play to this script.  So we now see claims for “chrome free” leather, or for “eco friendly” leather.

In last week’s post, I pointed out two kinds of leather tanning – chromium and vegetable. Although most leather is tanned using chromium (from 80 – 95% of all leather produced[1]) there is a third type of leather tanning, called aldehyde tanning, which like vegetable tanning does not use chromium.  Let’s revisit leather tanning for a minute:

  1. Sometimes leather manufacturers will tell you that they don’t use the toxic form of chromium in tanning – the toxic form is called chromium IV or hexavalent chromium.  And that is correct:  chromium tanned leathers use chromium III salts (also called trivalent chromium) in the form of chromium sulfate.  This form of chromium is found naturally in the environment and is a necessary nutrient for the human body.   However, the leather manufacturers fail to explain that  chromium III oxidizes into chromium IV in the presence of oxygen combined with other factors, such as extremes in pH.  This happens during the tanning process.  Chromium-tanned leather can contain between 4 and 5% of chromium [2] – often hexavalent chromium, which produces allergic reactions and easily moves across membranes such as skin.  End of life issues, recovery and reuse are a great concern – chromium (whether III or IV) is persistent (it cannot be destroyed) and will always be in the environment.   Incineration, composting and gasification will not eliminate chromium.
  2. Vegetable tanning is simply the replacement of the chromium for bark or plant tannins – all other steps remain the same.  And since there are about 250 chemicals used in tanning, the replacement of chromium for plant tannins, without addressing the other chemicals used, is a drop in the bucket.   Last week I mentioned some of the other 249 chemicals routinely used in tanning:  alcohol, coal tar , sodium sulfate, sulfuric acid, chlorinated phenols (e.g. 3,5-dichlorophenol), azo dyes, cadmium, cobalt, copper, antimony, cyanide, barium, lead, selenium, mercury, zinc, polychlorinated biphenyels (PCBs), nickel, formaldehyde and pesticide residues.[3]   Here are the steps to creating leather :
  3. Aldehyde tanning is the main type of leather referred to as “chrome-free”, and is often used in automobiles and baby’s shoes.  Aldehyde tanning is often referred to as “wet white” due to the pale cream color it imparts to the skins.  But aldehydes are a group of chemicals that contain one chemical which many people are familiar with: formaldehyde.  And we all know about formaldehyde: it is highly toxic to all animals; ingestion of as little as little as 30 mL (1 oz.) of a solution containing 37% formaldehyde has been reported to cause death in an adult human[4]  and the Department of Health and Human Services has said it may reasonably be anticipated to be a carcinogen.  Aldehyde tanning essentially uses formaldehyde, which reacts with proteins in the leather to prevent putrefication.  BLC Leather Technology Centre,  a leading independent leather testing center, states that leathers should contain no more than 200ppm of formaldehyde for articles in general use. If the item is in direct skin contact this should be 75ppm, and 20ppm for items used by babies (<36 months). Typically, with modern tanning techniques, leathers contain 400ppm or less.[5]   Yet that far exceeds levels set elsewhere – in New Zealand, for example, acceptable levels of formaldehyde in products is set at 100 ppm[6]  – the European Union Ecolabel restricts formaldehyde to 20 ppm for infant articles, 30 ppm for children and adults, while GOTS prohibits any detectable level.

BLC Leather Technology Centre Ltd.  commissioned a study by Ecobilan S.A (Reference BLC Report 002)  to do a life cycle analysis to evaluate the various tanning chemicals, to see if there was an environmentally preferable choice between chrome, vegetable and aldehyde based processes.  The result?  They found no significant differences between the three  – all have environmental impacts, just different ones.  These LCA’s demonstrate that tanning is just one of the impacts – other steps may have equal impacts.   Chrome was sited as having the disadvantage of being environmentally persistent. “Another consideration, in terms of end-of-life leather or management of chrome tanned leather waste, is the possibility of the valency state changing from the benign Cr III to the carcinogenic Cr VI.”[7]

So much for “chrome free” leather.  What about claims for “eco leather”?

In the strict sense of the definition, the term “eco leather” is meaningless. However, retailers want to imply improved environmental performance. So how can you evaluate their claims for “eco leathers”?

There are two main considerations in making leather:

  • How is it manufactured?
  • What inputs are used to produce it?

Research has shown that a significant part of the environmental impact of leather is in the manufacturing process.  In this respect it is the environmental stewardship practice of tanners coupled with chemical selection that should determine how eco friendly a leather is.  The following areas of leather manufacture have the most significant potential impact:

  • Management of restricted substances
  • Energy consumption
  • Air emissions
  • Waste management (hazardous and non hazardous)
  • Environmental management systems
  • Water consumption
  • Control of manufacturing processes
  • Effluent treatment
  • Chrome management
  • Traceability of material

In terms of the selection of inputs, we should consider the use of certain materials that could give an improved eco profile to leather. These include:

  • Biodegradable wetting agents for soaking
  • Reduced sulphide processing
  • Non synthetic or polymeric re-tannage systems
  • optimized dyestuffs
  • Vegetable oil based fatliquors
  • Optimised finishing systems to reduce waste such HVLP or roller coating
  • Biodegradable in 12 months or less

In summary, although there is no current definition, these are the key elements which should determine an “eco leather”:

  1. Control of leather manufacturing processes
  2. Clean technology chemical selection in the process
  3.  Effective management of restricted substances within the leather
  4. A measure of the end of life impact

As I mentioned in last week’s post, the production of leather can be a hellish life for the animal.  I have found only one company, Organic Leather, which looks beyond the production of the leather itself to the important questions of animal husbandry and land management practices which provide the skins, and incorporate these into a tanning process which “prevents further toxicity entering our environment and our bodies.”

The Leather Working Group (LWG)   is a multi-stakeholder group[8], whose purpose is  “to develop and maintain a protocol that assesses the compliance and environmental performance of tanners and promotes sustainable and appropriate environmental business practices within the footwear leather industry.”   The LWG, in conjunction with BLC Leather Technology Center Ltd., operates an eco rating system for leather. (This sort of mark is known as a first or second party certification, and lacks – I believe – the credibility of a true third party certification.)   Retailers, brands or tanners who are able to meet the requirements of this standard are eligible to use the EcoSure mark. To be eligible to use this mark tanneries must have achieved at least a Bronze award in the LWG Tannery Environment Auditing Protocol,  and the finished leather on which the mark is to be used must meet the requirements of the audit and testing regime. (to see the audit form, click here  ).

One issue which is a hot topic in leather production is that of deforestation and the sourcing of skins from Brazil – cattle ranching in Brazil accounted for 14% of global deforestation and ranches occupy approximately 80% of all deforested land in the Amazon.[9]  Greenpeace and the National Wildlife Federation (NWF) aims to stop all deforestation in the Amazon by encouraging the meat processors to insist that their suppliers register their farms and map and log their boundaries as a minimum requirement. They also encourage companies to cancel orders with suppliers that are not prepared to stop deforestation and adhere to these minimum requirements.  Many of the LWG member brands have  made commitments to a moratorium on hides sourced from farms involved in deforestation and LWG itself has a project to identify and engage with the key stakeholders in Brazil, investigate traceability solutions, conduct trials and implement third party auditing solutions.


[1] Richards, Matt, et al, “Leather for Life”, Future Fashion White Papers, Earth Pledge Foundation

[2] Gustavson, K.H. “The Chemistry of Tanning Processes” Academic Press Inc., New York, 1956.

[3] Barton, Cat, “Workers pay high price at Bangladesh tanneries”, AFP, Feb. 2011

[4] Agency for Toxic Substances & Disease Registry, “Medical management guidelines for formaldehyde”, http://www.atsdr.cdc.gov/mmg/mmg.asp?id=216&tid=39

[5] BLC Leather Technology Center Ltd, “Technology Restricted substances – Formaldehyde”, Leather International,  November 2008,  http://www.leathermag.com/news/fullstory.php/aid/13528/Technology_Restricted_substances-Formaldehyde.html

[6] “Evaluation of alleged unacceptable formaldehyde levels in Clothing”, Wellington, New Zealand: New Zealand Ministry of Consumer Affairs, October 17, 2007.

[8] Currently the consumer brands involved with the LWG are: Adidas-group, Clarks International, Ikea of Sweden, New Balance Athletic Shoe, Nike Inc, Pentland Group including (Berghaus, Boxfresh, Brasher, Ellesse, Franco Sarto, Gio-Goi, Hunter, KangaROOS, Mitre, Kickers (UK), Lacoste Chaussures, ONETrueSaxon, Radcliffe, Red or Dead, Speedo, Ted Baker Footwear), The North Face, The Timberland Company, Wolverine World Wide Inc including (CAT, Merrel, Hush Puppies, Patagonia, Wolverine, Track n Trail, Sebago, Chaco, Hytest, Bates, Cushe, Soft Style). New brands recently joined are Airwair International Ltd, K-Swiss International, Marks & Spencers and Nine West Group.

[9] “Broken Promises: how the cattle industry in the Amazon is still connected to deforestation…” Greenpeace, October 2011; http://www.leatherworkinggroup.com/images/documents/Broken%20promises%20-%20Oct11FINAL.pdf





Printing – part 3

19 01 2012

Yes, we’re still talking about the printing process!  As I warned you, it’s complicated.

For the past two weeks we’ve concentrated on the first two steps of the basic 5 steps in printing a fabric, which  are:

1. Preparation of the print paste.

2. Printing the fabric.

3. Drying the printed fabric.

4. Fixation of the printed dye or pigment.

5. Afterwashing.

So let’s look at the rest of the steps – drying, fixation and afterwashing.

Actually, the printing process begins even before passing  the fabric thru the printing presses, because the fabric must be conditioned.  The cloth must always to be brushed, to free it from loose nap, flocks and dust that it picks up while stored. Frequently, too, it has to be sheared by being passed over rapidly revolving knives arranged spirally round an axle, which rapidly and effectually cuts off all filaments and knots, leaving the cloth perfectly smooth and clean and in a condition fit to receive impressions of the most delicate engraving. Some figured fabrics, especially those woven in checks, stripes and crossovers, require very careful stretching and straightening on a special machine, known as a stenter, before they can be printed with certain formal styles of pattern which are intended in one way or another to correspond with the cloth pattern. Finally, all descriptions of cloth are wound round hollow wooden or iron centers into rolls of convenient size for mounting on the printing machines.

Immediately after printing, the fabric must be dried  in order to retain a sharp printed mark and to facilitate handling between printing and subsequent processing operations.

Two types of dryers are used for printed fabric, steam coil or natural gas fired dryers, through which the fabric is conveyed on belts, racks, etc., and steam cans, with which the fabric makes direct contact. Most screen printed fabrics and practically all printed knit fabrics and terry towels are dried with the first type of dryer, not to stress the fabric. Roller printed fabrics and apparel fabrics requiring soft handling are dried on steam cans, which have lower installation and operating costs and which dry the fabric more quickly than other dryers.

After printing and drying, the fabric is often cooled by blowing air over it or by passing it over a cooling cylinder to improve its storage properties prior to steaming, which is the process which fixes the color into the fabric.  Steaming may be likened to a dyeing operation.  Before steaming, the bulk of the dyestuff is held in a dried film of thickening agent.  During the steaming operation, the printed areas absorb moisture and form a very concentrated dyebath, from which dyeing of the fiber takes place.  The thickening agent prevents the dyestuff from spreading outside the area originally printed, because the printed areas act as a concentrated dyebath that exists more in the form of a gel than a solution and restricts any tendency to bleed.  Excessive moisture can cause bleeding, and insufficient moisture can prevent proper dyestuff fixation.  Steaming is generally done with atmospheric steam, although certain tyepes of dyestuffs, such as disperse dyes, can be fixed by using superheated steam or even dry heat.  In a few instances, acetic or formic acid is added to the steam to provide the acid atmosphere necessary to fix certain classes of dyes.  Temperatures in the steamer must be carefully controlled to prevent damage from overheating due to the heat swelling of the fabric, condensation of certain chemicals, or the decomposition of reducing agents.

Flash aging is a special fixation technique used for vat dyes. The dyes are printed in the insoluble oxidized state by using a thickener which is very insoluble in alkali. The dried print is run through a bath containing alkali and reducing agent, and then directly into a steamer, where reduction and color transfer take place.

After steaming, the printed fabric must not be stored for too long prior to washing because reducing agent residues may continue to decompose, leading to heat build up in the stacked material and defective dyeing or even browning of the fibers. If a delay of several hours is anticipated before the wet aftertreatment the fabric should be cooled with air (called “skying”) to oxidize at least some of the excess reducing agent.

Finally, printed goods must be washed thoroughly to remove thickening agent, chemicals, and unfixed dyestuff.  Washing of the printed material begins with a thorough rinsing in cold water.  After this, reoxidation is carried out with hydrogen peroxide in the presence of a small amount of acetic acid at 122 – 140 degrees F. A soap treatment with sodium carbonate at the boiling point should be begun only after this process is complete. This washing must be carefully done to prevent staining of the uncolored portions of the fabric.  Drying of the washed goods is the final operation of printing. 

And there you have it – a beautifully printed fabric that you can proudly display. Bet you know the subject of the next post – the environmental consequences of all this. Stay tuned.





Certifications: Oeko Tex

28 07 2011

I have an apology to make:  I made a statement last week that turns out to be incorrect, based on experience from years ago.  I said

“it’s not unusual to find a GOTS certification logo on a product – because it’s hard to get, and those who have it certainly want to display the logo.  But the certification may apply only to the organic fibers – the logo itself is not specific as to what is being certified.”

Laurie Lemmlie-Leung, of Sapphire International, Ltd, which is a GOTS certified terry mill, pointed out that in their experience,  “If we do not have an approved “GOTS Product Specification Plan” and transaction certificates showing that all the inputs are also GOTS certified, then we cannot use the GOTS label on the product.”  And that is indeed the case:  a GOTS logo on any product means that all processing up to the final product is GOTS certified.  So if GOTS certified cotton yarn is being sold, it can display the logo.  However, if that yarn is used to weave a fabric in a non-certified facility, the final fabric cannot display the logo.

So when you see a GOTS logo on a product, you can rest assured that the entire supply chain has been certified.

Now, back to discussion of certifications:  Before giving a summary of the main points of each of the certifications which deal with fiber processing (i.e., weaving), it’s important to remember that most of these certification programs are in business – so it costs money to achieve the certification – sometimes it costs a LOT of money.  In addition there is the burden of documentation, which increases administrative costs for the manufacturer.

Cradle to Cradle and GreenGuard can cost quite a bit, so when you look on the web sites to find which products have these certifications,  you see mostly large, well established companies which can afford to absorb the certification costs.  On the GreenGuard website, for example, it lists 1943 individual products, but all 1943 products are manufactured by only 20 large, well-known companies.  Sometimes smaller manufacturers decide not to pay the costs of certification, even though they may be doing everything “by the book”, because they’re operating on a shoestring.  Unfortunately, the many unethical claims make third party certification a requirement.

In addition to certifications, there are many new “green guides” on the internet which purport to list green products.  Some are valiantly trying to make order out of chaos, while others are simply adding to the confusion.  Of these, a basic listing may (or may not) be free, but any additional bells and whistles costs money.  So green products may be specially featured or identified (sometimes as “best”) because the manufacturer has paid for the spotlight.  The same is true of television shows which purport to cover new green products.  We have been approached several times by television programs featuring a well-known personality who would wax eloquently about our fabrics – if only we were to pay the right price.

What does this all mean?  Do your own homework!  Most of these “experts” have no more knowledge than you do.  And again, certifications provide a reliable yardstick to determine quality standards.

The third party certifications which cover textile processing and/or final products which you’ll see most often include:

  • Oeko Tex
  • GreenGuard
  • Cradle 2 Cradle by MBDC
  • Global Organic Textile Standard
  • Global Recycle Standard
  • SMART Sustainable Textile Standard

These are the certifications you’re most likely to run into, and they are very different.  So different, in fact, that we’ll take a few weeks to explore what each one tells us.

This week, we’ll start with one of the oldest certifications:  Oeko Tex.

Oeko Tex is an independent, third party certifier that offers two certifications for textiles:

  1. Oeko-Tex 100 (for products)
  2. Oeko-Tex 1000 (for production sites/factories).

Products satisfying the criteria for Oeko-Tex 100 which are produced in an Oeko-Tex 1000 certified facility may use the Oeko-Tex 100Plus mark, which is simply a combination of the two.

Oeko Tex was founded in 1992, by the Austrian Textile Research Intitute (OTI) and the German Research Institute Hohenstein,  to provide an objective and reliable product label for consumers.  Its aim is to ensure that products posed no risk to health.

Oeko Tex Standard 100

The Oeko-Tex Standard 100 standard is concerned primarily with health and safety of textile products – it tests only the end product.  The processing is not addressed – for example, wastewater treatment is not included.   It is NOT an organic certification and products bearing this mark are not necessarily made from organically grown fibers. (Note:  When you see the logo, make sure that the test number is quoted (No. 11-20489 in the image above)  and the test institute is named (Shirley is the institute which tested the product).)

Textiles considered for this standard are classified into four categories, and each category has different test values for chemicals allowed in the product:

  • Product Class I: Products for Babies – all textile products and materials used to manufacture such textile products for children up to the age of 36 months (leather clothing is excepted)
  • Product Class II: Products with Direct Contact to Skin – worn articles of which a large surface touches the skin (i.e. underwear, shirts, pants)
  • Product Class III: Products without Direct Contact to Skin – articles of which only a small part of their surface touches the skin (i.e. linings, stuffings)

Textile products bearing the Oeko-Tex 100 certification mark:

  • Do not contain allergenic dye-stuffs and dye stuffs that form carcinogenic arylamines.
  • Have been tested for pesticides and chlorinated phenoles.
  • Have been tested for the release of heavy metals under artificial perspiration conditions.
  • Formaldehyde is banned; other aldehyde limits are significantly lower than the required legal limits.
  • Have a skin friendly pH.
  • Are free from chloro-organic carriers.
  • Are free from biologically active finishes.

The certification process includes thorough testing for a lengthy list of chemicals, including lead, antimony, arsenic, phthalates, pesticides, and chlorinated phenols. The official table of limits for tested chemicals may be found on the Oeko-Tex website.  Specifically banned are:

  • AZO dyes
  • Carcinogenic and allergy-inducing dyes
  • Pesticides
  • Chlorinated phenols
  • Chloro-organic benzenes and toluenes
  • Extractable heavy metals
  • Phthalates in baby articles
  • Organotin compounds(TBT and DBT)
  • Emissions of volatile components

Certification may be given to a finished product (such as a shirt), or to individual components (such as yarn, or fabric).

Oeko-Tex Standard 1000

The Oeko-Tex 1000 is a certification for environmentally-friendly textile production.
The goal of the Oeko-Tex 1000 Standard is to be “an evaluation of the environmental performance of textile production sites and products and to document independently that certain environmental measures are undertaken and a certain level achieved.”

The evaluation process includes considerations for:

  • environmental impact: energy consumption, whether materials used are renewable or non-renewable, and the overall impact of the space utilized
  • global impact: use of fossil fuels, use of ozone-depleting chemicals regional impact: VOC’s, water contamination, acidification of soil and water from fossil fuel use, emissions (often from chlorine bleaching)
  • local effects: emissions, workplace contamination, noise, use of dangerous chemical products

The mark is not applied directly to products, but may be used by the production site (for example, on its letterhead and official documents). The “local effects” consideration does NOT include an evaluation of labor practices and is not meant to be an indicator of whether a production site is following fair labor practices.

Oeko-Tex 100Plus

This label may be used on products that have met the Oeko-Tex 100 Standard and are also produced in a facility that meets the Oeko-Tex 1000 Standard.

So, these are the important points to keep in mind when you see the Oeko Tex logo:

  1. Oeko Tex 100 is product specific – they don’t look at processing (i.e., water treatment, workers rights, emissions, sludge), it only means that the finished product (fabric, yarn, clothing, etc.) has limit values for chemicals which are below the threshold limits on the Oeko Tex list, with many specifically prohibited.
  2. Oeko Tex 1000 is site specific, and documents that certain environmental standards are met, but these do not include workers rights issues.
  3. Oeko Tex 100+ means that the site meets environmental standards and the product itself is safe to use.




When is recycled polyester NOT recycled polyester?

23 03 2011

Fabric might be the only product I can think of which is known by its component parts, like cotton, silk, wool.  These words usually refer to the fabric rather than the fiber used to make the fabric.  We’ve all done it: talked about silk draperies, cotton sheets.  There seems to be a disassociation between the fibers used and the final product, and people don’t think about the process of turning cotton bolls or silkworm cocoons or flax plants into luxurious fabrics.

There is a very long, involved and complex process needed to turn raw fibers into finished fabrics.  Universities award degrees in textile engineering,  color chemistry or any of a number of textile related fields.  One can get a PhD in fiber and polymer science,  or study the design, synthesis and analysis of organic dyes and pigments.  Then there is the American Association of Textile Chemists and Colorists (AATCC) which has thousands of members in 60 different countries.  My point is that we need to start focusing on the process of turning raw textile fiber into a finished fabric – because therein lies all the difference!

And that brings me to recycled polyester, which has achieved pride of place as a green textile option in interiors.  We have already posted blogs about plastics (especially recycled plastics) last year (on 4.28.10, 5.05.10 and 5.12.10) so you know where we stand on the use of plastics in fabrics.  But the reality is that polyester bottles exist,  and recycling some of them  into fiber seems to be a better use for the bottles than landfilling them.

But today the supply chains for recycled polyester are not transparent, and if we are told that the resin chips we’re using to spin fibers are made from bottles – or from any kind of  polyester  –  we have no way to verify that.  Once the polymers are at the melt stage, it’s impossible to tell where they came from, because the molecules are the same.  So the yarn/fabric  could be virgin polyester or  it could be recycled.   Many so called “recycled” polyester yarns may not really be from recycled sources at all because – you guessed it! – the process of recycling is much more expensive than using virgin polyester.   And unfortunately not all companies are willing to pay the price to offer a real green product, but they sure do want to take advantage of the perception of green.   So when you see a label that says a fabric is made from 50% polyester and 50% recycled polyester – well, there is absolutely no way to tell if that’s true.

Some companies are trying to differentiate their brands by confirming that what they say is recycled REALLY is from recycled sources.  Unifi, which supplies lots of recycled resins and yarns, has an agreement with Scientific Certification Systems to certify that their Repreve yarns are made from 100% recycled content.  Then Unifi’s  “fiberprint” technology audits orders across the supply chain to verify that if Repreve is in a product , that it’s present in the right amounts.  But with this proprietary information there are still many questions Unifi doesn’t answer – the process is not transparent.  And it applies only to Unifi’s branded yarns.

Along with the fact that whether what you’re buying is really made from recycled yarns – or not – most people don’t pay any attention to the processing of the fibers.  Let’s just assume, for argument’s sake, that the fabric (which is identified as being made of 100% recycled polyester) is really made from recycled polyester.  But unless they tell you specifically otherwise, it is processed conventionally.  That means that the chemicals used during processing – the optical brighteners, texturizers, dyes, softeners, detergents, bleaches and all others – probably contain some of the chemicals which have been found to be harmful to living things.  The processing uses the same amount of water (about 500 gallons to produce 25 yards of upholstery weight fabric) – so the wastewater is probably expelled without treatment, adding to our pollution burden.  And there is no guarantee that the workers who produce the fabric are being paid a fair wage – or even that they are working in safe conditions.

One solution, suggested by Ecotextile News, is to create a tracking system that follows the raw material through to the final product.  They assumed that this would be very labor intensive and would require a lot of monitoring (all of which adds to the cost of production – and don’t forget, recycled polyester now is fashion’s darling because it’s so cheap!).

But now, Ecotextile News‘ suggestion has become a reality.   There is a new, third party certification which is addressing these issues.  The Global Recycle Standard (GRS), issued by Control Union, is intended to establish independently verified claims as to the amount of recycled content in a yarn. The GRS provides a track and trace certification system that ensures that the claims you make about a product can be officially backed up. It consists of a three-tiered system with the Gold standard requiring products to contain between 95 percent to 100 percent recycled material; the Silver standard requires products to be made of between 70 percent to 95 percent recycled product; and the Bronze standard requires products to have a minimum of 30 percent recycled content.

And – we think this is even more important –  in addition to the certification of the recycled content, the GRS looks at the critical issues of processing and workers rights.  This new standard holds the weaver to similar standards as found in the Global Organic Textile Standard:

  • companies must keep full records of the use of chemicals, energy, water consumption and waste water treatment including the disposal of sludge;
  • all prohibitied chemicals listed in GOTS are also prohibited in the GRS;
  • all wastewater must be treated for pH, temperature, COD and BOD before disposal;
  • there is an extensive section related to worker’s health and safety.





What effects do fabric choices have on you?

9 03 2011

 

 


 

Let’s look at just three areas in which your fabric choice impacts you directly:

1.      What are residual chemicals in the fabrics doing to you and the planet?

2.      What are the process chemicals expelled in treatment water  doing to us?

3.      Why do certain fiber choices accelerate climate change?

RESIDUAL CHEMICALS IN THE FABRICS:

  • It takes between 10% and 100% of the weight of the fabric in chemicals to produce that fabric.[1] Producing enough fabric to cover ONE sofa uses 4 to 20 lbs. of chemicals – and the final fabric is about 27%  synthetic chemicals by weight.[2]
  • In the mills, textile clippings must be handled like toxic waste, according to OSHA regulations (see Note below).  The fabrics we bring into our homes contain chemicals which are outlawed in other products.   Many fabrics sold in the USA are outlawed in China, Japan and the EU – because of the chemicals found in the fabrics.
  • Chemicals which remain in the fabric are absorbed by our bodies: some chemicals outgas into the air; some are absorbed through our skin.  Another way our bodies absorb these chemicals:   over time, microscopic particles are abraded and fall into the dust in our homes where pets and crawling children breathe them in.
  • Chemicals used routinely in textile processing – and found in the fabrics we live with – include those that bioaccumulate, persist in our environment and contribute to a host of human diseases.  They include, but are not limited to,  formaldehyde, benzene, lead, cadmium, mercury and chlorine, which are all used a lot.[3]
  • Why do we continue to allow fabrics into our lives that contain chemicals which have been demonstrated to affect us in many ways, from subtle to profound?  Chemicals used in textile processing are contributing to the chemical onslaught which many feel has led to increases in a host of health issues:  infertility, asthma, nervous disorders from depression and anxiety to brain tumors, immune system suppression and genetic alterations.  Why are we taking a chance?

PROCESS CHEMICALS EXPELLED IN TREATMENT WATER:

  • The textile industry is the #1 industrial polluter of water in the world.[4]
  • Vast quantities of water are returned to our ecosystem, untreated, filled with process chemicals – chemicals which circulate in the groundwater of our planet.
  • Because these chemicals are released into the environment, they become available to living organisms (like us).  That’s why PBDE’s (a fire retardant chemical widely used in the textile and electronics industries) are found in the blood of every animal in the world, from the Artic to the Amazon –  in the most remote parts of the world, far from any industry.[5] And the rate of increase for PBDE’s is rising exponentially.
  • Disease rates correlated with chemical exposure are on the rise – You can send your children to private schools and provide the best medical care in the world, but you can’t protect them from chemical pollution.

 

CLIMATE CHANGE:

  • The U.S. textile industry is the 5th largest contributor to CO2 emissions, by industry, in the United States.[6] (The production of the U.S. textile industry is mostly synthetics, and these egregious GHG emissions are largely from the production of synthetics.)  Given the size of the U.S. textile industry, it seems a disproportionatly high percentage.  Image what the textile industry contributes globally.
  • Not only is the quantity of greenhouse gas emissions of concern regarding synthetics, but so is the quality:  Nylon, for example, creates emissions of NO2, which is 300 times more damaging than CO2 [7] and which, because of its long life (120 years) can reach the upper atmosphere and deplete the layer of stratospheric ozone, which is an important filter of UV radiation.  Polyester production generates particulates, CO2, N2O, hydrocarbons, sulphur oxides and carbon monoxide,[8] acetaldehyde and 1,4-dioxane (also potentially carcinogenic).[9]
  • The production of synthetics is heavily dependent on oil – it’s made from oil and it takes a lot to produce the fibers.  The embodied energy in 1 KG of polyester is much greater than the embodied energy in 1 KG of many common building products, including steel, as shown in the chart here:

Data compiled from "LCA: New Zealand Merino Wool Total Energy Use" by Barber and Pellow; EMBODIED ENERGY AND CO2 COEFFICIENTS FOR NZ BUILDING MATERIALS by A Alcorn, 2003

 

 

You, as a consumer, are very powerful. You have the power to change harmful production practices. Eco textiles exist and they give you a greener, healthier, fairtrade alternative.  What will an eco textile do for you? You and the frogs and the world’s flora and fauna could live longer, and be healthier – and in a more just, sufficiently diversified, more beautiful world.

 


[1] Working Report No. 10,2002 from the Danish EPA.  Danish experience: Best Available Techniques (BAT) in the clothing and textile industry, document prepared for the European IPPC Bureau and the TWG Textile.  See also  Voncina, B and Pintar, M, “Textile Waste Recycling”,  University of Maribor, Slovenia, from the proceedings of the 10th International Conference on Environmental Science and Technology, September 2007

[2] Lacasse and Baumann, Textile Chemicals:,  Environmental Data and Facts, Springer, New York, 2004, page 609.

NOTE: From: http://www.fibre2fashion.com/industry-article/3/297/safety-and-health-issues-in-the-textile-industry2.asp: OSHA requirements based on such studies as these:

A study conducted in USA revealed a correlation between the presence of cancer of the buccal cavity and pharynx and occupation in the textile industry. Another study revealed that textile workers were at high risk for developing cancer of the stomach while another study indicated a low degree of correlation between oesophageal cancer and working in the textile industry. Moreover, a high degree of colorectal cancer, thyroid cancer, testicular cancer and nasal cancer was observed among textile workers. Also, a relationship between the presence of non-Hodgkin’s lymphoma and working in the textile industry was observed.

[3] See, for example:

  • “Killer Couches”, Sara Schedler,  Friends of the Earth, www.foe.org
  • “Dioxins and Dioxin-like Persistent Organic Pollutants in Textiles and Chemicals in the Textile Sector”, Bostjan Krizanec and Alenka Majcen Le Marechal, Faculty of Mechanical Engineering, Smetanova 17, SI-2000 Maribor, Slovenia; January 24, 2006
  • “Potentials for exposure to industrial chemicals suspected of causing developmental neurotoxicity”, Philippe Grandjean, MD, PhD, Adjunct Professor and Marian Perez, MPH, Project Coordinator,
  • “The Chemicals Within” , Anne Underwood, Newsweek, January 26, 2008
  • Williams, Florence, “Toxic Breast Milk”, New York Times Magazine, January 9, 2005

[4] Cooper, Peter, “Clearer Communication”, Ecotextile News, May 2007

[6] Energy Information Administration, Form EIA:848, “2002 Manufacturing Energy Consumption Survey,” Form EIA-810, “Monthly Refinery Report” (for 2002) and Documentatioin for Emissions of Greenhouse Gases in the United States 2003 (May 2005). http://www.eia.doe.gov/emeu/aer/txt/ptb1204.html

[7] “Tesco carbon footprint study confirms organic farming is energy efficient, but excludes key climate benefit of organic farming, soil carbon”, Prism Webcast News, April 30, 2008, http://prismwebcastnews.com/2008/04/30/tesco-carbon-footprint-study-confirms-organic-farming%E2%80%99s-energy-efficiency-but-excludes-key-climate-benefit-of-organic-farming-%E2%80%93-soil-carbon/

[8] “Ecological Footprint and Water Analysis of Cotton, Hemp and Polyester”, by Cherrett et al, Stockholm Environment Institute

[9] Gruttner, Henrik, Handbook of Sustainable Textile Purchasing, EcoForum, Denmark, August 2006.





What can be considered the “good” chemicals in textile processing?

9 02 2011

We’re often asked if ALL the chemicals used in textile processing are harmful.  And the answer is (surprisingly maybe)  no!   Many chemicals are used, many benign, but as with everything these days there are caveats.

Let’s look at the chemical that is used  most often in the textile industry:  salt.  That’s right.  Common table salt.  Safe, natural salt is used in textile dyeing.

Salt shaker painting by Jeff Hayes

The way the dyestuff bonds to the fibers is very important – and the most permanent, wash fast dyes are the most tightly attached to the fiber molecules (called reactive dyes).  Here’s how salt comes into the picture:

To dye a fabric made of a cellulosic fiber (i.e., cotton, hemp, linen) or its close cousin (viscose),  the fabric is put into water, where its surface gets covered in negative ionic charges.  The reactive dyes used most often to dye cellulosic fabrics also develops a negative charge, so the fibers actually repel the dye – like two magnets repelling each other.   If we try to dye a cellulosic fabric without using  salt, the dye molecules just roll off the surface of the fibers and the fabric does not show much color change.

But when salt is added to the water, the solution splits into positive sodium ions (Na+) and negative chlorine ions (Cl-).  The  positive Na+  ions then dive into the surface of the fabric to neutralize the negative charge.

The dye molecules are then attracted to the fiber by weak Van der Waals forces and as the dyes get close to the fiber molecules, the salt acts like a glue to hold the dyes in place.  If we add alkali, the dyestuff will permanently grab hold of the fiber and become a part of the fiber molecule rather than remaining as an independent chemical  entity.

The color fastness of reactive dyes is so good that  it’s no wonder that they have become so widely used.  And natural salt has been crucial to their success.

We sprinkle salt on our foods – indeed salt is essential for life itself.  But (there is always a “but”) the “dose makes the poison”  – and the textile industry uses a LOT of salt!

The concentrations to suppress those negative ions can be as high as 100 gm per liter.  In the worst cases, 1 kg of salt is used to apply reactive dye to 1 kg of fabric.  Think of the billions of yards of fabric that’s produced each year:   In Europe alone, 1 million tons of salt is discharged into our waterways each year.[1] In areas where salt is discharged into the ecosystem, it takes a long, long time for affected areas to recover, especially in areas of sparse rainfall – such as Tirupur, India.

Tirupur is one of the world’s centers for clothing production , home of 765 dyeing and bleaching industries.  These dyehouses  had been dumping untreated effluent into the Noyyal River for years, rendering the water unsuitable or irrigation – or drinking.   In 2005, the government shut down 571 dyehouses  because of the effluent being discharged into the Noyyal.  The mill owners said they simply couldn’t afford to put pollution measures into place.   The industry is too important to India to keep the mills closed for long, so the government banned the discharge of salt and asked for an advance from the mills before allowing them to re-open.     But … on February 4, 2011, the Madras high court ordered 700 dye plants to be shut down because of the damage the effluent was doing to the local environment.  Sigh.  (Read more about Tirupur here.)

Unfortunately, the salt in textile effluent is not made harmless by treatment plants and can pass straight through  to our rivers even if treated.  This salt filled effluent can wreak havoc with living organisms.

There are some new “low salt” dyes that require only half the amount of “glue”, but these dyes are not widely used because they’re expensive – and manufacturers are following our lead in demanding ever cheaper fabrics.

Recycling the salt is possible, and this has been used by many of the dyers in Tirupur, and elsewhere, who operate zero discharge facilities.  The effluent is cleaned and then the salt is recovered using an energy intensive process to evaporate the water and leave the solid, re-useable salt.

This sounds like a good idea – it reduces the pollution levels – but the carbon footprint goes through the roof, so salt recovery isn’t necessarily the best option.  In fact, in some areas of the world where water is plentiful and the salt can be diluted in the rivers adequately, it may be better to simply discharge salt than to recover it.

But the best option is to avoid salt altogether.

Next week we’ll look at how to do that.


[1] Dyeing for a change: Current Conventions and New Futures in the Textile Color Industry (2006, July) www.betterthinking.co.uk





Estimating the carbon footprint of a fabric

19 01 2011

We published this blog almost two years ago, but the concepts haven’t changed and we think it’s very important.   So here it is again:

Although most of the current focus on lightening our carbon footprint revolves around transportation and heating issues, the modest little fabric all around you turns out to be from an industry with a gigantic carbon footprint. The textile industry, according to the U.S. Energy Information Administration, is the 5th largest contributor to CO2 emissions in the United States, after primary metals, nonmetallic mineral products, petroleum and chemicals.[1]

The textile industry is huge, and it is a huge producer of greenhouse gasses.  Today’s textile industry is one of the largest sources of greenhouse gasses (GHG’s) on Earth, due to its huge size.[2] In 2008,  annual global textile production was estimated at  60 billion kilograms (KG) of fabric.  The estimated energy and water needed to produce that amount of fabric boggles the mind:

  • 1,074 billion kWh of electricity  or 132 million metric tons of coal and
  • between 6 – 9 trillion liters of water[3]

Fabrics are the elephant in the room.  They’re all around us  but no one is thinking about them.  We simply overlook fabrics, maybe because they are almost always used as a component in a final product that seems rather innocuous:  sheets, blankets, sofas, curtains, and of course clothing.  Textiles, including clothing,  accounted for about one ton of the 19.8 tons of total CO2 emissions produced by each person in the U.S. in 2006. [4] By contrast, a person in Haiti produced a total of only 0.21 tons of total carbon emissions in 2006.[5]

Your textile choices do make a difference, so it’s vitally important to look beyond thread counts, color and abrasion results.

How do you evaluate the carbon footprint in any fabric?  Look at the “embodied energy’ in the fabric – that is, all of the energy used at each step of the process needed to create that fabric.  To estimate the embodied energy in any fabric it’s necessary to add the energy required in two separate fabric production steps:

(1)  Find out what the fabric is made from, because the type of fiber tells you a lot about the energy needed to make the fibers used in the yarn.  The carbon footprint of various fibers varies a lot, so start with the energy required to produce the fiber.

(2) Next, add the energy used to weave those yarns into fabric.  Once any material becomes a “yarn” or “filament”, the amount of energy and conversion process to weave that yarn into a textile is pretty consistent, whether the yarn is wool, cotton, nylon or polyester.[6]

Let’s look at #1 first: the energy needed to make the fibers and create the yarn. For ease of comparison we’ll divide the fiber types into “natural” (from plants, animals and less commonly, minerals) and “synthetic” (man made).

For natural fibers you must look at field preparation, planting and field operations (mechanized irrigation, weed control, pest control and fertilizers (manure vs. synthetic chemicals)), harvesting and yields.  Synthetic fertilizer use is a major component of the high cost of conventional agriculture:  making just one ton of nitrogen fertilizer emits nearly 7 tons of CO2 equivalent greenhouse gases.

For synthetics, a crucial fact is that the fibers are made from fossil fuels.   Very high amounts of energy are used in extracting the oil from the ground as well as in the production of the polymers.

A study done by the Stockholm Environment Institute on behalf of the BioRegional Development Group  concludes that the energy used (and therefore the CO2 emitted) to create 1 ton of spun fiber is much higher for synthetics than for hemp or cotton:

KG of CO2 emissions per ton of spun fiber:
crop cultivation fiber production TOTAL
polyester USA 0.00 9.52 9.52
cotton, conventional, USA 4.20 1.70 5.90
hemp, conventional 1.90 2.15 4.05
cotton, organic, India 2.00 1.80 3.80
cotton, organic, USA 0.90 1.45 2.35

The table above only gives results for polyester; other synthetics have more of an impact:  acrylic is 30% more energy intensive in its production than polyester [7] and nylon is even higher than that.

Not only is the quantity of GHG emissions of concern regarding synthetics, so too are the kinds of gasses produced during production of synthetic fibers.  Nylon, for example, creates emissions of N2O, which is 300 times more damaging than CO2 [8] and which, because of its long life (120 years) can reach the upper atmosphere and deplete the layer of stratospheric ozone, which is an important filter of UV radiation.  In fact, during the 1990s, N2O emissions from a single nylon plant in the UK were thought to have a global warming impact equivalent to more than 3% of the UK’s entire CO2 emissions.[9] A study done for the New Zealand Merino Wool Association shows how much less total energy is required for the production of natural fibers than synthetics:

Embodied Energy used in production of various fibers:
energy use in MJ per KG of fiber:
flax fibre (MAT) 10
cotton 55
wool 63
Viscose 100
Polypropylene 115
Polyester 125
acrylic 175
Nylon 250

SOURCE:  “LCA: New Zealand Merino Wool Total Energy Use”, Barber and Pellow,      http://www.tech.plym.ac.uk/sme/mats324/mats324A9%20NFETE.htm

Natural fibers, in addition to having a smaller carbon footprint in the production of the spun fiber, have many additional  benefits:

  1. being able to be degraded by micro-organisms and composted (improving soil structure); in this way the fixed CO2 in the fiber will be released and the cycle closed.   Synthetics do not decompose: in landfills they release heavy metals and other additives into soil and groundwater.  Recycling requires costly separation, while incineration produces pollutants – in the case of high density polyethylene, 3 tons of CO2 emissions are produced for ever 1 ton of material burnt.[10] Left in the environment, synthetic fibers contribute, for example, to the estimated 640,000 tons of abandoned fishing nets in the world’s oceans.
  2. sequestering carbon.  Sequestering carbon is the process through which CO2 from the atmosphere is absorbed by plants through photosynthesis and stored as carbon in biomass (leaves, stems, branches, roots, etc.) and soils.  Jute, for example, absorbs 2.4 tons of carbon per ton of dry fiber.[11]

Substituting organic fibers for conventionally grown fibers is not just a little better – but lots better in all respects:  uses less energy for production, emits fewer greenhouse gases and supports organic farming (which has myriad environmental, social and health benefits).  A study published by Innovations Agronomiques (2009) found that 43% less GHG are emitted per unit area under organic agriculture than under conventional agriculture.[12] A study done by Dr. David Pimentel of Cornell University found that organic farming systems used just 63% of the energy required by conventional farming systems, largely because of the massive amounts of energy requirements needed to synthesize nitrogen fertilizers. Further it was found in controlled long term trials that organic farming adds between 100-400kg of carbon per hectare to the soil each year, compared to non-organic farming.  When this stored carbon is included in the carbon footprint, it reduces the total GHG even further.[13] The key lies in the handling of organic matter (OM): because soil organic matter is primarily carbon, increases in soil OM levels will be directly correlated with carbon sequestration. While conventional farming typically depletes soil OM, organic farming builds it through the use of composted animal manures and cover crops.

Taking it one step further beyond the energy inputs we’re looking at, which help to mitigate climate change, organic farming helps to ensure other environmental and social goals:

  • eliminates the use of synthetic fertilizers, pesticides and genetically modified organisims (GMOs) which is  an improvement in human health and agrobiodiversity
  • conserves water (making the soil more friable so rainwater is absorbed better – lessening irrigation requirements and erosion)
  • ensures sustained biodiversity
  • and compared to forests, agricultural soils may be a more secure sink for atmospheric carbon, since they are not vulnerable to logging and wildfire.

Organic agriculture is an undervalued and underestimated climate change tool that could be one of the most powerful strategies in the fight against global warming, according to Paul Hepperly, Rodale Institute Research Manager. The Rodale Institute Farming Systems Trial (FST) soil carbon data (which covers 30 years)  provides convincing evidence that improved global terrestrial stewardship–specifically including regenerative organic agricultural practices–can be the most effective currently available strategy for mitigating CO2 emissions.

At the fiber level it is clear that synthetics have a much bigger footprint than does any natural fiber, including wool or conventionally produced cotton.   So in terms of the carbon footprint at the fiber level, any natural fiber beats any synthetic – at this point in time.   Best of all is an organic natural fiber.

And next let’s look at #2, the energy needed to weave those yarns into fabric.

There is no dramatic difference in the amount of energy needed to weave fibers into fabric depending on fiber type.[14] The processing is generally the same whether the fiber is nylon, cotton, hemp, wool or polyester:   thermal energy required per meter of cloth is 4,500-5,500 Kcal and electrical energy required per meter of cloth is 0.45-0.55 kwh. [15] This translates into huge quantities of fossil fuels  –  both to create energy directly needed to power the mills, produce heat and steam, and power air conditioners, as well as indirectly to create the many chemicals used in production.  In addition, the textile industry has one of the lowest efficiencies in energy utilization because it is largely antiquated.

But there is an additional dimension to consider during processing:  environmental pollution.  Conventional textile processing is highly polluting:

  • Up to 2000 chemicals are used in textile processing, many of them known to be harmful to human (and animal) health.   Some of these chemicals evaporate, some are dissolved in treatment water which is discharged to our environment, and some are residual in the fabric, to be brought into our homes (where, with use, tiny bits abrade and you ingest or otherwise breathe them in).  A whole list of the most commonly used chemicals in fabric production are linked to human health problems that vary from annoying to profound.
  • The application of these chemicals uses copious amounts of water. In fact, the textile industry is the #1 industrial polluter of fresh water on the planet.[16] These wastewaters are discharged (largely untreated) into our groundwater with a high pH and temperature as well as chemical load.

Concerns in the United States continue to mount about the safety of textiles and apparel products used by U.S. consumers.  Philadelphia University has formed a new Institute for Textile and Apparel Product Safety, where they are busy analyzing clothing and textiles for a variety of toxins.  Currently, there are few regulatory standards for clothing and textiles in the United States.  Many European countries,  as well as Japan and Australia, have much stricter restrictions on the use of chemicals in textiles and apparel than does the United States, and these world regulations will certainly impact world production.

There is a bright spot in all of this:  an alternative to conventional textile processing does exist.  The new Global Organic Textile Standard (GOTS) is a  tool for an international common understanding of environmentally friendly production systems and social accountability in the textile sector; it covers the production, processing, manufacturing, packaging, labeling, exportation, importation and distribution of all natural fibers; that means, specifically, for example:  use of certified organic fibers, prohibition of all GMOs and their derivatives; and prohibition of a long list of synthetic chemicals (for example: formaldehyde and aromatic solvents are prohibited; dyestuffs must meet strict requirements (such as threshold limits for heavy metals, no  AZO colorants or aromatic amines) and PVC cannot be used for packaging).

A fabric which is produced to the GOTS standards is more than just the fabric:

It’s a promise to keep our air and water pure and our soils renewed; it’s a fabric which will not cause harm to you or your descendants.  Even though a synthetic fiber cannot be certified to  GOTS, the synthetic mill could adopt the same production standards and apply them.   So for step #2, the weaving of the fiber into a fabric, the best choice is to buy a GOTS certified fabric or to apply as nearly as possible the GOTS parameters.

At this point in time, given the technology we have now, an organic fiber fabric, processed to GOTS standards, is (without a doubt) the safest, most responsible choice possible in terms of both stewardship of the earth, preserving health and limiting toxicity load to humans and animals, and reducing carbon footprint – and emphasizing rudimentary social justice issues such as no child labor.

And that would be the end of our argument, if it were not for this sad fact:  there are no natural fiber fabrics made in the United States which are certified to the Global Organic Textile Standard (GOTS).  The industry has, we feel, been flat footed in applying these new GOTS standards.  With the specter of the collapse of the U.S. auto industry looming large, it seems that the U.S. textile industry would do well to heed what seems to be the global tide of public opinion that better production methods, certified by third parties, are the way to market fabrics in the 21st Century.


[1] Source: Energy Information Administration, Form EIA:848, “2002 Manufacturing Energy Consumption Survey,” Form EIA-810, “Monthly Refinery Report” (for 2002) and Documentatioin for Emissions of Greenhouse Gases in the United States 2003 (May 2005). http://www.eia.doe.gov/emeu/aer/txt/ptb1204.html

[2] Dev, Vivek, “Carbon Footprint of Textiles”, April 3, 2009, http://www.domain-b.com/environment/20090403_carbon_footprint.html

[3] Rupp, Jurg, “Ecology and Economy in Textile Finishing”,  Textile World,  Nov/Dec 2008

[4] Rose, Coral, “CO2 Comes Out of the Closet”,  GreenBiz.com, September 24, 2007

[5] U.S. Energy Information Administration, “International Energy Annual 2006”, posted Dec 8, 2008.

[6] Many discussions of energy used to produce fabrics or final products made from fabrics (such as clothing) take the “use” phase of the article into consideration when evaluating the carbon footprint.  The argument goes that laundering the blouse (or whatever) adds considerably to the final energy tally for natural fibers, while synthetics don’t need as much water to wash nor as many launderings.  We do not take this component into consideration because

  • it applies only to clothing; even sheets aren’t washed as often as clothing while upholstery is seldom cleaned.
  • is biodegradeable detergent used?
  • Is the washing machine used a new low water machine?  Is the water treated by a municipal facility?
  • Synthetics begin to smell if not treated with antimicrobials, raising the energy score.

Indeed, it’s important to evaluate the sponsors of any published studies, because the studies done which evaluate the energy used to manufacture fabrics are often sponsored by organizations which might have an interest in the outcome.  Additionally, the data varies quite a bit so we have adopted the values which seem to be agreed upon by most studies.

[7] Ibid.

[8] “Tesco carbon footprint study confirms organic farming is energy efficient, but excludes key climate benefit of organic farming, soil carbon”, Prism Webcast News, April 30, 2008, http://prismwebcastnews.com/2008/04/30/tesco-carbon-footprint-study-confirms-organic-farming%E2%80%99s-energy-efficiency-but-excludes-key-climate-benefit-of-organic-farming-%E2%80%93-soil-carbon/

[9] Fletcher, Kate, Sustainable Fashion and Textiles,  Earthscan, 2008,  Page 13

[10] “Why Natural Fibers”, FAO, 2009: http://www.naturalfibres2009.org/en/iynf/sustainable.html

[11] Ibid.

[12] Aubert, C. et al.,  (2009) Organic farming and climate change: major conclusions of the Clermont-Ferrand seminar (2008) [Agriculture biologique et changement climatique : principales conclusions du colloque de Clermont-Ferrand (2008)]. Carrefours de l’Innovation Agronomique 4. Online at <http://www.inra.fr/ciag/revue_innovations_agronomiques/volume_4_janvier_2009>

[13] International Trade Centre UNCTAD/WTO and Research Institute of Organic Agriculture (FiBL);    Organic Farming and Climate Change; Geneva: ITC, 2007.

[14] 24th session of the FAO Committee on Commodity Problems IGG on Hard Fibers of the United Nations

[15] “Improving profits with energy-efficiency enhancements”, December 2008,  Journal for Asia on Textile and Apparel,  http://textile.2456.com/eng/epub/n_details.asp?epubiid=4&id=3296

[16] Cooper, Peter, “Clearer Communication,” Ecotextile News, May 2007.