Why is recycled polyester considered a sustainable textile?

14 07 2009

 

plastic_bottles

Synthetic fibers are the most popular fibers in the world – it’s estimated that synthetics account for about 65% of world production versus 35% for natural fibers.[1] Most synthetic fibers (approximately 70%) are made from polyester, and the polyester most often used in textiles is polyethylene terephthalate (PET).   Used in a fabric, it’s most often referred to as “polyester” or “poly”.

The majority of the world’s PET production – about 60% – is used to make fibers for textiles; about 30% is used to make bottles.   It’s estimated that it takes about 104 million barrels of oil for PET production each year – that’s 70 million barrels just to produce the virgin polyester used in fabrics.[2] That means most polyester – 70 million barrels worth –  is manufactured specifically to be made into fibers, NOT bottles, as many people think.  Of the 30% of PET which is used to make bottles, only a tiny fraction is recycled into fibers.  But the idea of using recycled bottles – “diverting waste from landfills” – and turning it into fibers has caught the public’s imagination.

The reason recycled polyester (often written rPET) is considered a green option in textiles today is twofold, and the argument goes like this:

  1. energy needed to make the rPET is less than what was needed to make the virgin polyester in the first place, so we save energy.
  2. And  we’re keeping bottles and other plastics out of the landfills.

Let’s look at these arguments.

1) The energy needed to make the rPET is less than what is needed to make the virgin polyester, so we save energy:

 

It is true that recycling polyester uses less energy that what’s needed to produce virgin polyester.  Various studies all agree that it takes  from 33%  to 53% less energy[3].  If we use the higher estimate, 53%,  and take 53% of the total amount of energy needed to make virgin polyester (125 MJ per KG of ton fiber)[4], the amount of energy needed to produce recycled polyester in relation to other fibers is:

Embodied Energy used in production of various fibers:

energy use in MJ per KG of fiber:

hemp, organic

2

flax

10

hemp, conventional

12

cotton, organic, India

12

cotton, organic, USA

14

cotton,conventional

55

wool

63

rPET

66

Viscose

100

Polypropylene

115

Polyester

125

acrylic

175

Nylon

250

rPET is also cited as producing far fewer emissions to the air than does the production of  virgin polyester: again estimates vary, but Libolon’s website introducing its new RePET yarn put the estimate at 54.6% fewer CO2 emissions.  Apply that percentage to the data from the Stockholm Environment Institute[5], cited above:

KG of CO2 emissions per ton of spun fiber:

crop cultivation

fiber production

TOTAL

polyester USA

0

9.52

9.52

cotton, conventional, USA

4.2

1.7

5.89

rPET

5.19

hemp, conventional

1.9

2.15

4.1

cotton, organic, India

2

1.8

3.75

cotton, organic, USA

0.9

1.45

2.35

Despite the savings of both energy and emissions from the recycling of PET, the fact is that it is still more energy intensive to recycle PET into a  fiber than to use organically produced natural fibers – sometimes quite a bit more energy.

2) We’re diverting bottles and other plastics from the landfills.

 

That’s undeniably true,  because if you use bottles then they are diverted!

But the game gets a bit more complicated here because rPET is divided into “post consumer” PET and “post industrial” rPET:  post consumer means it comes from bottles; post industrial might be the unused packaging in a manufacturing plant, or other byproducts of manufacturing.  The “greenest” option has been touted to be the post consumer PET, and that has driven up demand for used bottles. Indeed, the demand for used bottles, from which recycled polyester fibre is made, is now outstripping supply in some areas and certain cynical suppliers are now buying NEW, unused bottles directly from bottle producing companies to make polyester textile fiber that can be called recycled.[6]

Using true post consumer waste means the bottles have to be cleaned (labels must be removed because labels often contain PVC) and sorted.  That’s almost always done in a low labor rate country since only human labor can be used.   Add to that the fact that the rate of bottle recycling is rather low – in the United States less than 6% of all waste plastic gets recycled [7].  The low recycling rate doesn’t mean we shouldn’t continue to try, but in the United States where it’s relatively easy to recycle a bottle and the population is relatively well educated in the intricacies of the various resin codes, doesn’t it make you wonder how successful we might be with recycling efforts in other parts of the world?

pet-recycling-graph-2 SOURCE: Container Recycling Institute

There are two types of recycling:  mechanical and chemical:

    • Mechanical recycling is accomplished by melting the plastic and re-extruding it to make yarns.  However, this can only be done  few times before the molecular structure breaks down and makes the yarn suitable only for the landfill[8] where it may never biodegrade, may biodegrade very slowly, or may add harmful materials to the environment as it breaks down (such as antimony).  William McDonough calls this  “downcycling”.
    • Chemical recycling means breaking the polymer into its molecular parts and reforming the molecule into a yarn of equal strength and beauty as the original.  The technology to separate out the different chemical building blocks (called depolymerization) so they can be reassembled (repolymerization) is very costly and almost nonexistent.

Most recycling is done mechanically (or as noted above, by actual people). Chemical recycling does create a new plastic which is of the same quality as the original,  but the process is very expensive and is almost never done, although Teijin has a new program which recycles PET fibers into new PET fibers.

The real problem with making recycled PET a staple of the fiber industry is this:  recycling, as most people think of it, is a myth.  Most people believe that plastics can be infinitely recycled  – creating new products of a value to equal the old bottles or other plastics which they dutifully put into recycling containers to be collected. The cold hard fact is that there is no such thing as recycling plastic, because it is not a closed loop.  None of the soda and milk bottles which are collected from your curbside are used to make new soda or milk bottles, because each time the plastic is heated it degenerates, so the subsequent iteration of the polymer is degraded and can’t meet food quality standards for soda and milk bottles.  The plastic must be used to make lower quality products.  The cycle goes something like this:

  • virgin PET can be made into soda or milk bottles,
  • which are collected and recycled into resins
    • which are appropriate to make into toys, carpet, filler for pillows, CD cases, plastic lumber products,  fibers or a million other products. But not new soda or milk bottles.
  • These second generation plastics can then be recycled a second time into park benches, carpet, speed bumps or other products with very low value.
  • The cycle is completed when the plastic is no longer stable enough to be used for any product, so it is sent to the landfill
    • where it is incinerated (sometimes for energy generation, which a good LCA will offset)  -
    • or where it will hold space for many years or maybe become part of the Great Pacific Garbage Patch![9]

And there is another consideration in recycling PET:  antimony, which is present in 80 – 85% of all virgin PET[10], is converted to antimony trioxide at high temperatures – such as are necessary during recycling, releasing this carcinogen from the polymer and making it available for intake into living systems.

Using recycled PET for fibers also creates some problems specific to the textile industry:

  • The base color of the recycled polyester chips vary from white to creamy yellow, making color consistency difficult to achieve, particularly for the pale shades.  Some dyers find it hard to get a white, so they’re using chlorine-based bleaches to whiten the base.
  • Inconsistency of dye uptake makes it difficult to get good batch-to-batch color consistency and this can lead to high levels of re-dyeing, another very high energy process.  Re-dyeing contributes to high levels of water, energy and chemical use.
  • Unsubstantiated reports claim that some recycled yarns take almost 30% more dye to achieve the same depth of shade as equivalent virgin polyesters.[11]
  • Another consideration is the introduction of PVC into the polymer from bottle labels and wrappers.
  • Many rPET fibers are used in forgiving constructions such as polar fleece, where the construction of the fabric hides slight yarn variations.  For fabrics such as satins, there are concerns over streaks and stripes.

Once the fibers are woven into fabrics, most fabrics are rendered non-recyclable  because:

  • the fabrics almost always have a chemical backing, lamination or other finish,
  • or they are blends of different synthetics (polyester and nylon, for example).

Either of these renders the fabric unsuitable for the mechanical method of recycling, which cannot separate out the various chemicals in order to produce the recycled yarn; the chemical method could  –   if we had the money and factories to do it.

One of the biggest obstacles to achieving McDonough’s Cradle-to-Cradle vision lies outside the designers’ ordinary scope of interest – in the recycling system itself. Although bottles, tins and newspapers are now routinely recycled, furniture and carpets still usually end up in landfill or incinerators, even if they have been designed to be  recycled [12] because project managers don’t take the time to separate out the various components of a demolition job, nor is collection of these components an easy thing to access.

Currently, the vision that most marketers has led us to believe, that of a closed loop, or cycle, in which the yarns never lose their value and recycle indefinitely is simply that – just a vision.  Few manufacturers, such as Designtex (with their line of EL fabrics designed to be used without backings) and Victor Innovatex (who has pioneered EcoIntelligent™ polyester made without antimony),  have taken the time, effort and money needed to accelerate the adoption of sustainable practices in the industry so we can one day have synthetic fabrics that are not only recycled, but recyclable.


[1]“New Approach of Synthetic Fibers Industry”, Textile Exchange,  http://www.teonline.com/articles/2009/01/new-approach-of-synthetic-fibe.html

[2] Polyester, Absolute Astronomy.com: http://www.absoluteastronomy.com/topics/Polyester and Pacific Institute, Energy Implications of Bottled Water, Gleick and Cooley, Feb 2009, http://www.pacinst.org/reports/bottled_water/index.htm)

[3] Website for Libolon’s RePET yarns:  http://www.libolon.com/eco.php

[4] Data compiled from:  “LCA: New Zealand Merino Wool Total Energy Use”, Barber and Pellow,                                                                       http://www.tech.plym.ac.uk/sme/mats324/mats324A9%20NFETE.htm and  “Ecological Footprint and Water

Analysis of Cotton, Hemp and Polyester”, by Cherrett et al, Stockholm Environment Institute

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

[6] The Textile Dyer, “Concern over Recycled Polyester”,May 13, 2008,

[7] Watson, Tom, “Where can we put all those plastics?”, The Seattle Times, June 2, 2007

[8] William McDonough and Michael Braungart, “Transforming the Textile Industry”, green@work, May/June 2002.

[9] See http://www.greatgarbagepatch.org/

[10] Chemical Engineering Progress, May 2003

[11] “Reduce, re-use,re-dye?”,  Phil Patterson, Ecotextile News, August/September 2008

[12] “Taking Landfill out of the Loop”, Sarah Scott, Azure, 2006

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44 responses

14 07 2009
Harmony

You did it again! Educated me, brought complex information together in a comprehensive, cohesive (referenced) way. Thank you for this thoughtful and informative post.

14 07 2009
oecotextiles

Thanks so much for the morale boost, Harmony! Leigh Anne

16 07 2009
Mandy Behrens

Exceptional article! Harmony put it best. Cheers!

19 07 2009
Anna

Excellent article but I still have some questions. If all PET is made with antimony, what happens to the antimony? Is it treated from the waste water? Also, rPET causes antimony tri to be released. Where? Do these chemicals reside in the fabrics after they are completed?

The problem that I see is that rPET is being used in the commercial arena due to its supposed durability. What can designers use instead? Do cotton and hemp have enough rubs so that you are not reupholstering ever few years? Can part organic cotton and hemp be used with another eco friendly material to give it that durability? Wool can be tricky due to people’s sensitivities.

19 07 2009
oecotextiles

The antimony used in the production of the PET fibers becomes chemically bound to the PET polymer (although some is leached from the fibers during the high temperature dyeing process) so your PET fabric does contain antimony. The antimony that leaches from the fibers during the dyeing process is expelled with the wastewater into our rivers (unless the fabric is woven at a mill which treats its wastewater).
But what about the antimony that remains in the PET fabric? We do know that antimony leaches from PET bottles into the water or soda inside the bottles. But the US Agency for Toxic Substances and Disease Registry says that the antimony in fabric is very tightly bound and does not expose people to antimony. So if you want to take the government’s word for it, antimony in PET is not a problem for human health. (Toxics crusader William McDonough has been on antimony’s case for years, however, and takes a much less sanguine view of antimony.)
It’s just not a nice thing to be eating or drinking, and wearing it probably won’t hurt you, but the problem comes up during the production process – is it released into our environment? Recycling PET is a high temperature process, which creates wastewater tainted with antimony trioxide – and the dyeing process for recycled PET is problematic as I mentioned in last week’s post. Another problem occurs when the PET (recycled or virgin) is finally incinerated at the landfill – because then the antimony is released as a gas.
You’re right that designers are in love with polyesters because they’re so durable – and cheap (don’t forget cheap!). So they’re used a lot for public spaces. Abrasion results are a function not only of the fiber but also the construction of the fabric, and cotton and hemp can be designed to be very durable, but they will never achieve the same abrasion results that some polyesters have achieved – like 1,000,000 rubs. In the residential market, I would think most people wouldn’t want a fabric to last that long – I’ve noticed sofas which people leave on the streets with “free” signs on them, and never once did I notice that the sofa was suffering from fabric degredation! The “free” sofa just had to go because it was out of style, or stained, or something – I mean, have you even replaced a piece of furniture because the fabric had actually worn out? Hemp linens have been known to last for generations.
But synthetic fibers can do many things that make our lives easier, and in many ways they’re the true miracle fibers. I think there will always be a place for (organic) natural fibers, which are comfortable and soothing next to human skin. And they certainly have that cachet: doesn’t silk damask sound better than Ultrasuede? The versatile synthetics have a place in our textile set – but I think the current crop of synthetics must be changed so the toxic inputs are removed and the nonsustainable feedstock (oil) is replaced. I have great hope for the biobased polymer research going on, because the next generation of miracle fibers just might come from sustainable sources.

20 07 2009
Anna

I actually had 2 couches that were covered with a beautiful cotton print, which in five years with kids looked like it had seen much better days. Totally torn in many places.

The cost to reupholster and fabric is so expensive so I opted for a recycled poly fabric for duarability since I was so neverous about having to redo these couches again. I went with longevity. They told me no antimony was used in creating the fabric, but I am not sure they knew. At the time, there was not an organic cotton out there that had enough rubs. Would backing a cotton fabric helped with durability? Would it be much more expensive?

What are you thoughts on the Eco intelligent recycle polys?

20 07 2009
oecotextiles

Oh boy, I empathize with the part about your sofas taking a beating from kids. I have 3 boys, and we’ve had assorted dogs, so I totally know what you’re looking for in durability. Was the fabric construction on your sofa a sturdy one with a hefty weight? In any event, I can sure understand why you wanted to go with durability. For a bit of background: cotton as a fiber is much softer and of shorter lengths than either hemp or linen. Hemp is the most durable natural fiber, and researchers claim it has from 2 to 3x the tensile strength of cotton. Cotton is also a very short fiber (coming from the flower), averaging 0.79 -1.30 inches in length. Hemp’s average length is 8 inches, but can easily range up to 36” in length.

Backing the cotton fabric will help with durability. There are several backings you could use, each involving tradeoffs:
• A cotton knit backing (tradeoff: the cotton is probably not organic, and the adhesive used to glue the backing to the face should be nontoxic, and these are rare)
• A polyester backing: (tradeoff: this renders both the polyester and the cotton non-recyclable – really a moot point, but worth considering + issues surrounding use of plastics). Some would say why do this to a natural fiber, but which is better: a polyester backing on a natural fiber fabric or a polyester fabric (using more polyester)?
I don’t know about the cost to you for the backings; they would certainly increase the cost of the fabric!

Regarding the antimony in your fabric – if the fabric was made from polyester (which has the least toxic profile of all the synthetics) then the chances of it having antimony were pretty high, since 90% of the PET produced worldwide uses antimony as a catalyst in the production of the PET.

If they don’t use antimony as a catalyst they have to use something else, like Titanium. Not very many companies are taking the time and effort to change their manufacturing cycles, nor can they. It’s a huge investment to change the production process. There are very few companies that DO offer antimony free polyester, like Victor Innovatex which produces EcoIntelligent polyester, or Teijin in Japan. If I were buying a polyester I’d buy the antimony free polyester. But please remember that the EcoIntelligent polyesters are NOT recycled polyesters – they’re virgin polyester. So again you have to make a trade off – use the higher energy cost in producing the product, or have the toxins released into our ecosystem at some point during the product’s life. That’s why I think we need to give people better choices.

21 07 2009
Anna

Does antimony releases itself once it is on your couches. I was so careful not to use flame retardants, change the pads to natural latex, and was told that the fabric was antimony free.

About hemp, so which weight would be durable for rug rats? Why is some hemp you feel on sofas scatchy?

22 07 2009
oecotextiles

I think most of the research shows that it’s not a danger if antimony is in a fabric on our sofas, because the molecules are bound together chemically – it doesn’t become a free agent, as it were. The real danger is to our environment, thru release of the excess antimony in the mill effluent and again as antimony trioxide – which happens whenever the polymers are heated (as in polyester recycling, or during end of life burning at landfills). Another consideration that we think if worth noting: the literature is full of chemicals that the government and others told us were safe, only to be told further down the line that they weren’t. Look at lead: in 1971, the U.S. Surgeon General said that 60 mg of lead in a deciliter of blood was a safe level. In 1985 they reduced that to 25 mg, then in 1991 it was reduced to 10 mg and now we know that any detectable level of lead will shave off IQ points. Antimony causes cancer in mice and they know that exposure is cumulative- do you want it in your home, even if it IS bound in the polymer? What if they’re wrong?

It’s hard to give a specific weight for a hemp fabric that would be durable – if it looks to you like a sturdy fabric and it has a certain heft, then you should be good to go. If the fabric looks flimsy, or you can see thru it – then probably not.

Hemp has been given a bad rap because it IS a difficult fiber to work with. It can also be very coarse and scratchy, as you say. It takes an extra effort to make the hemp fibers soft, and until recently nobody was willing to spend the time and money on a fiber that many people wouldn’t consider buying because they equated it with rope. (By the way, hemp fibers soften and become more lustrous as they age, so old hemp fabrics are often very soft with a wonderful hand). Add to that the fact that you can’t even grow hemp in the United States, so research was spent on our best cash crop – cotton. And none of the mills in the U.S. could spin hemp, so it became the forgotten fiber.

It’s possible to find hemp fibers blended with other, softer fibers, such as cotton or viscose.

4 11 2009
Milan

I’m sorry if I’m bringing old topics back to life, but I have a question and I’m hoping you can help me with my dilemma. I’m looking for a skiing jacket and Patagonia is making great ones out of recycled polyester. Is it a smart thing to buy? If we suppose that they are using mechanical recycling method does that mean that the jackets they make have weaker fabric?
Thanks in advance,
Milan

4 11 2009
oecotextiles

Hi Milan: You know, just today I heard a great line: “Don’t expect to buy green products from brown companies”. That means that there are lots of companies jumping on the bandwagon – maybe they’ll add a couple of green products, or if they’re a fabric distributor with 60,000 skus they’ll introduce their new “green” collection of 48 skus. What percent of 60,000 is 48? (I actually used an online percentage calculator and got an answer that was so low as to be NA!). Do you think that company is seriously trying to make a difference? Well, Patagonia is NOT one of those brown companies. I’ve been impressed by Patagonia’s committment to our environment and the many steps they have taken for so long – in terms of research, new trials, new products, the whole works. There is a web site which gives an update on their Common Threads program (the recycling of garments) where you can read about some of the issues they’re grappeling with (http://www.thecleanestline.com/2009/03/closing-the-loop-a-report-on-patagonias-common-threads-garment-recycling-program.html). And though there are some unresolved issues about recycling polyester – and using plastics – I would support Patagonia because their heart’s in the right place and I trust them. And I would never think they’d sell a fabric for their jackets that has not been thoroughly tested. After all, they need to remain a vigorous company to fight the good fight!

5 11 2009
Milan

Thank you for your prompt response and let me express my support for your work, you’re doing an excellent work.

25 11 2009
Susan

Great article!!

I’m working on a line of children’s stuffed toys and was considering using a fleece made from recycled plastic (similar to Patagonia) or an organic cotton fleece.

rPET fleece is extremely flammable and I don’t want to add a fire retardant. I am also concerned a baby sleeping with a rPET fleece toy might be at risk for absorbing antimony. Do you think that is a possibility?

27 11 2009
oecotextiles

Hi Susan: I know exactly what you’re going through in trying to find a good source for your stuffed toys: the polyester is really cheap, right, and the organic cotton puts the price out of the ballpark? You’re worried that people won’t buy the toys if the price is too high?

You’re right that rPET would contain antimony (85% of all virgin polyester is made using antimony as a catalyst), but I think most of the research finds that antimony’s not a danger if it is in a fabric, because the molecules are bound together chemically – it doesn’t become a free agent. So the thinking is that the toxic element is there, it’s just not available to be ingested – the baby sleeping with the toy would not be harmed by the antimony in that toy at that moment But think about the long term effect of using this plastic: it will not degrade – it will just break down into smaller and smaller pieces, some of which will find their way into our food chain.) There is a real danger to our environment, thru the release of the excess antimony in the mill effluent and again as antimony trioxide – which happens whenever the polymers are heated (as in polyester recycling, or during end of life burning at landfills). Another source of pollution is in the mill sludge, which can contain very high levels of antimony. So also think about the kind of world we want to leave this peacefully sleeping baby.

And especially because you’re producing a product that will be used by young children we think it’s important to think about the effect that antimony just might have on children. The literature is full of chemicals that the government and others told us were safe, only to be told further down the line that they weren’t. Look at lead: in 1971, the U.S. Surgeon General said that 60 mg of lead in a deciliter of blood was a safe level. In 1985 they reduced that to 25 mg, then in 1991 it was reduced to 10 mg and now we know that any detectable level of lead will shave off IQ points. Antimony causes cancer in mice and they know that exposure is cumulative- do you want it in your home, even if it IS bound in the polymer? And what if they’re wrong?

3 12 2009
Susan

Thanks for the reply. You solidified my decision to go with 100% organic cotton fleece and stuffing. I believe in the Precautionary Principle especially when it comes to children’s products. I have worked with plastics for most of my career and agree with you that we are still on the precipice of learning the full outcome of living with them.
I think my best bet for my supply chain would be to partner with a clothing manufacturer that uses organic fleece and hopefully use their waste stream scraps. If you have any suggestions, I would appreciate them immensely.

Thanks!

3 03 2010
Athene

Hi there,

Your article was amazingly informative and really helpful. I wonder if you might be able to help me further. I am in the early stages of setting up a clothing company that caters mainly for the surfing population. We are really keen to be as eco concious as possible when it comes to the fabrics we use. We intend to use Hemp, Bamboo and Organic Cotton fabrics for the ‘out of water’ items but the swimming trunks and bikinis need to be high performance materials that dry quickly, are light and flexible (spandex is being mixed with Polyester to achieve a new stretch fabric that is very popular) and do not chaffe.
We are struggling to find a fabric that performs as well as the polyester, Lycra & Spandex blends in the water that is also environmentally friendly. So far with the little resources we have, recycled polyester seemed like the best option but after reading your article I am wandering if there is anything better? Aaarrrggghhh I so don’t want to be a Brown company as you put it but being eco friendly is pretty complex!
Do you have any suggestions?

Many thanks,

Athene

3 03 2010
oecotextiles

Hi Athene: I really appreciate your comment that being eco friendly is pretty complex! It is. But I applaud your trying – if we all raised the same questions we’d begin to get somewhere. But we also live in the real world, and for specific uses such as you describe (high performance, quick drying, light, flexible and non chafing) – well, that might mean using a recycled polyester – or virgin polyester if it’s antimony free (see our blog posting on the differences). But please remember that just as important as the fiber choice is the processing: was the water treated at the mill where the polyester was produced; did the mill capture emissions; did they use REACH or GOTS certified dyestuffs – or perhaps did they dope dye the polymers (that means mixing the dye into the polymer itself, so no water is used in the application); did they pay a fair wage? I think if you ask these questions, at least the mills will know the market demand is growing so maybe they’ll begin to change. And you can tell your consumers exactly what they’re buying. A part of being green, for me, is transparency. Good luck! Best, Leigh Anne

3 03 2010
Athene

Hi Leigh Anne,

Thank you very much for your advise, I will certainly do my best to check out all these factors. The research begins now!

You are an awesome eco agony aunt!

Athene

11 05 2010
Cecilia

Hello!
And thank you for a great article.
I have I question though. Is it correct with the unit:
“KG of CO2 emissions per ton of spun fiber”?
Shouldn´t it be “KG of CO2 emissions per kg of spun fiber”?
Best regards,
Cecilia

11 05 2010
oecotextiles

Thanks for the support! With regard to your question, it’s correct as stated. It is really almost intuitively correct, because if you were to produce just 2.2 pounds of fiber (or 1 KG) – and if that production produced 2.2 POUNDS of emissions (which are gasses and don’t weigh much) we’d really be in serious trouble. So producing one TON of fiber creates much less gas by weight, measured in kilograms. You can see the original data for yourself at:

http://www.organicexchange.org/Farm/Reading%20and%20References/Cotton%20Hemp%20Polyester%20study%20SEI%20and%20Bioregional%20and%20WWF%20Wales.pdf

11 05 2010
Cecilia

Ok!
So have I understood correct that for example “cotton, conventional, USA” the emission of 1 ton of fibre is 5.89 kg CO2?
/Cecilia

11 05 2010
oecotextiles

You got it – for spun fiber. At least, that’s what the data from the Stockholm Environment Institute reports.

17 05 2010
Sherzod

Dear Leigh Anne,

Our company is in the process of setting-up PET bottle (mechanical) recycling line, where we would take bottles, have them cleaned and make them into synthetic fibers to be used in textile.

Your article was very refreshing and thank you very much!

9 06 2010
Cecilia

Hello again,
I think it should be approx 6 kg CO2 per kg cotton, not per ton cotton. At least to all sources I use, for example ecoinvent, GABI and other studies I have found, see for example http://www.unep.org/climateneutral/Portals/4/Carbon20footprint20Stormberg20April200820ENG20VER_a7NIO.pdf.pdf
or

http://www.leeds.ac.uk/autex/v1n1/2264_99.pdf

In this report the also talk about 4-6 kg CO2 per kg cotton.
What do you think?
Best regards,
Cecilia

9 06 2010
oecotextiles

Hi Cecilia: This is a case which demonstrates how incredibly complex LCA analysis can be, and how we have to be extremely careful to make sure we’re comparing apples to apples. I checked my source, which is the Stockholm Environment Institute’s LCA comparing hemp, cotton and polyester, which does indeed give data for CO2 in KG for one ton of spun fiber. (http://www.organicexchange.org/Farm/Reading%20and%20References/Cotton%20Hemp%20Polyester%20study%20SEI%20and%20Bioregional%20and%20WWF%20Wales.pdf)

Next I checked the Stromberg study you mention, and found that the data in that report is for clothing – an entirely different kettle of fish. But they did assign “cotton production” 5.3 KG of CO2 per KG. However, they didn’t define “cotton production” – is that the fiber only, spun fiber, yarn or the woven fabric? But even so, the comparison between the SEI study I used (KG CO2 per ton of spun fiber) and the Stromberg study (5.3 KG of CO2 per KG of “cotton production”) don’t relate well. The Autex study assigns cotton 3 KG of CO2 emissions per KG of fiber – again seeming to substantiate the KG of CO2 per KG of fiber. But I find that just a bit counterintuitive – I mean, CO2 is a gas, after all. I did a bit more checking and found several descriptions of cotton fabric listed in terms of KGs of CO2 per KG of product. So I think you may be right.

Can anybody else clarify this for us?

13 09 2010
Chris

Hi,
Interesting thread you started. I have looked at the SEI report you refer to and I’m afraid I cannot correlate the figures you quote for energy use and which you show in your table ‘MJ per KG of fiber’. Obviously they are quoting per tonne and you are quoting per KG but that doesnt account for the discrepencies. Maybe I am missing something but for e.g. Hemp Organic they have as about 17 or 18, you have stated 2. Whats the explanation?
Thanks!

13 09 2010
oecotextiles

HI Chris:
Thanks for pointing out what seems to be a misleading statement. First let me start by saying that the SEI report table is a bit hard to interpret, so I refer to their written explanation, in which they say hemp, organic, processed conventionally, is 13.5 MJ per KG rather than 17 or 18.
But as you say, that is quite a bit more than 2! At the time I did this blog, I was drawing on a variety of different LCA’s, and it was difficult to compare apples to apples. For example, the LCA done by the University of Plymouth (http://www.tech.plym.ac.uk/sme/mats324/mats324A9%20NFETE.htm) listed the embodied energy in 1 KG of sisal to be 2.0 MJ – and I used that data to support my extrapolation for the value for the crop cultivation only from the chart in the SEI report. At the time, I thought it was unfair to add the scutching, hackling, roving, drawing and wet spinning of hemp into the equation. So I used the SEI values (as best as I could determine) for the natural fibers for the crop cultivation only. I realize now that is misleading, since the crop cannot be used as fiber unless it is scotched, hackled, drawn and spun.
So the revised data should read:
MJ per KG
flax 10
cotton, organic, Punjab 11.7
cotton, org uSA 12
hemp, organic 13.5
hemp, conv 22
wool 49
rPET 66
Viscose 100
Polyester 125

NOTE: (1) new wool value is from a
new LCA study by the New Zealand Merino
Wool Association, http://www.agrilink.co.nz/Portals/Agrilink/Files/LCA_NZ_Merino_Wool.pdf
(2) Flax was not included in the SEI study, I used
the University of Plymouth data for non woven flax, cited above.
(3) the value for hemp, conventional, is my estimate of the value listed in the chart of the SEI report.

I think the important thing to get across is that the energy needed to produce the fiber for any synthetic is still more than is needed to produce any natural fiber – and in addition you don’t get the added benefits that are provided by supporting organic agriculture, such as carbon sequestration. But I’ll change all my documents to reflect this improved understanding. Thanks again for being such an eagle eye.

13 09 2010
Chris

Thats great, thanks, its a complicated subject this and wanted to be sure I wasnt misunderstanding something. Just so that you know we are involved in writing a project about Low Embodied Energy building materials using biocomposites, and its apparent that Life Cycle Analysis will become the standard for all walks of life.
Good work!

13 09 2010
oecotextiles

Thanks Chris. It IS a complicated subject, and we all need to make sure we’re comparing apples to apples, and look at each study’s parameters. I’d love to get any information you might uncover about fibers, since there is precious little available.

4 10 2012
Ed

Excellent article! I just stumbled upon it after reading about Nike’s work with sustainability. This post was more than informative. You should consider contributing to Wikipedia.

4 10 2012
O Ecotextiles

Thanks so much, I’m glad it was helpful!

1 11 2012
Shannonjaye

Hello,

I know this is an old thread but it is really fascinating. I’m a sales representative for a major upholstery line and am teaching a CEU about recycled polyesters. Your article popped up when I was doing a little verification and I was very impressed with all your research. Thank you and I would invite you to investigate the finishes manufacturers are adding on all of the polyester and poly blends to meet the needs of our clients, especially in the commercial sector (i.e., healthcare, higher education, hospitality). I’m curious about all these soil and stain repellents, moisture barriers and even the silver ion process seen mostly on vinyls or polyurethanes. There has been a lot of push back from designers in regard to the dyes (antimony and titanium) but I really wonder if the finishes aren’t more harmful in the end.

Thanks again for all your research!

4 11 2012
O Ecotextiles

Hi Shannonjaye: Thanks for the kind words – I’m glad you found the blog helpful.
One thing we’ve found is that people tend to react to whatever they’re reading in the media, and currently there has been a lot written about fire retardants (see the series in the Chicago Tribune, called Playing with Fire, http://oecotextiles.wordpress.com/2010/01/20/foam-for-upholstery-cushions/ ) and dyes. So people want to be sure they buy products which don’t have the toxic dyestuffs and/or fire retardants. But that means there are 1,998 other chemicals used in the fabrics which may cause health concerns.
One thing I wanted to point out is that vinyl and polyurethane are both fibers that are toxic in their own right, and don’t need any help with dyes or finishes of any sort. We did a blog post about polyurethane in foam in which you can read about the reason it’s just not good to live with: http://oecotextiles.wordpress.com/2010/01/20/foam-for-upholstery-cushions/

We also did a few posts about soil resistant finishes: http://oecotextiles.wordpress.com/2010/02/03/soil-and-stain-resistant-finishes/

http://oecotextiles.wordpress.com/2010/02/10/what-about-soil-resistant-finishes-like-scotchgard-goretex-nanotex-and-greenshield-are-they-safe/

And about silver:

http://oecotextiles.wordpress.com/2010/09/01/silver-and-other-nanoparticles-in-fabrics/

We’re slowly wending our way thru the world of finishes! One takeaway I hope you get is that we can’t separate out one chemical or process – it’s all of a piece and we need to revise the entire process. It’s not enough to say that something is dyed with heavy metal free dyestuffs if the processing uses APEO’s, optical brighteners, chlorine, biocides, PCPs, phthalates, benzene, and EDTA. Sorta like selling organic cigarettes.

3 01 2013
Cincinnati Recycling Services

I seldom leave comments, but after reading through a ton of remarks on Why
is recycled polyester considered a sustainable textile?
O ECOTEXTILES. I do have 2 questions for you if you tend not to mind.

Could it be only me or does it give the impression like some of the
responses appear like they are written by brain
dead people? :-P And, if you are writing on other online social sites, I
would like to keep up with you. Could you list of the complete urls
of your social community sites like your Facebook page, twitter feed, or linkedin profile?

3 01 2013
O Ecotextiles

Thanks so much for your comments, they’re really appreciated! But I have to admit that we’re woefully behing on social community sites, though we have a (mostly unvisited) Facebook page and a twitter feed, which just posts our blogs. Something we keep meaning to get back to.

10 01 2013
C K Polymers

Great article. At C K Polymers we believe that recycling is a great way to use waste products!, thank you

20 02 2013
CK Polymers

CK Polymers recycle plastics and polymers across the UK and Ireland. Great article., thanks

21 02 2013
Anna Strzelecki

So glad I have come across this blog, so informative but also a difficult discussion as it seems whatever materials we choose to use in garment design they are going to have some kind of negative impact so it’s really about making the best choices.
We are a small surfwear company based in the UK, we design, hand screen print (using waterbased inks) cut, sew, finish and sell garments of high quality all in our small studio in Wales. I believe in sourcing fabrics as locally as possible and currently source polyester fleece, and cotton jersey from a UK supplier. I am at a crucial point of expansion and really want to replace the current virgin fleece with recycled PET, and use organically grown cotton jersey. I will be asking the suppliers a lot of questions before placing any fabric order as I would like to show transparency to my customers so they know we really are trying to be as sustainable as possible.
Now I have read the above comments I am wondering if PET fleece is the answer or virgin fleece with no antimony? and if anyone knows anywhere I can source it in smallish quantities (50-250 mtrs)as I have yet to find a supplier in the UK, I am willing to go further afield in europe but we are really trying to keep our brand UK based in as many ways as possible to support the british econnomy and keep our carbon footprint as low as possible.
It is great to find a discussion like this I will definately be reading more of your blog, if anyone has any opinions or names of suppliers please let me know, it is sooo fustrating trying to do the right thing!

24 02 2013
O Ecotextiles

Hi Anna: As the saying goes, the longest journey begins with a single step. And the fact that you’re now aware of the consequences of our choices, and looking into using organic cotton, for example, is a huge step forward! Congratulations. As to fleece choice – that’s a difficult one, because of the energy/chemical tradeoff. I would mention though that Patagonia did a study on the carbon footprint of a fleece vest (sourced in one part of the world, sewn in another and then distributed around the world to their stores) and found that transportation made up only 2% of the total carbon footprint. This seems counterintuitive but if you understand how fleece – polyester – is made from crude oil and uses lots of energy to translate that crude into fleece yarn, then it’s easier to understand how resource intense the fleece is. So it might not matter that you source your fleece from overseas – at least in terms of carbon footprint, if not to the British economy!

24 02 2013
Anna Strzelecki

Hmmmm, my initial reaction is to not use polyester fleece at all, but unfortunately costs come into this and I simply don’t have the funds to make this choice right now but as my products are selling well hopefully soon I will make enough cash to switch to more sustainable fabrics such as organic cotton! At least I have an aim which will be written in to my company environmental policy immediately.
I am currently reading Yvon Choudinard’s book ‘Let my people go surfing’ all about how and why he set up Patagonia a truely inspirational read and highly recommended.
I will keep researching and keep doing the best I can to try to persuade people to buy better textile based products. I wish the big companies would do more, if they changed where they sourced their materials from the whole industry could be cleaned up and we could all use sustainable fabrics at reasonable prices, I live in hope!

18 03 2013
The Toadstool

Hi, I come from a fashion industry background (business development for Honestby) and have recently changed to the high quality toys industry after my pregnancy.
I was wondering if there is a straight forward answer why all baby toys are produced from 100% polyester and why they stress it is new material. Why is rPet not suitable for baby toys. I retail Haba and Lilliputiens whom both have and environmental interest, yet all cuddly toys are PES where as room furniture (eg growth charts) are in rPet. I assume it has to do with small fibre components which can be inhaled in little lungs, but I am not sure. Can you give me your expert view on this?
I aim to give my customers the option of making an informed decision when buying toys, and while growing I also hope to make the toy industry a little more transparent, so people understand value over buying only discounted items.

19 03 2013
O Ecotextiles

I can only guess that the reason is marketing – baby toys are associated with all things new, like baby! It cannot be because either PET or rPET is “better” – they’re both made of toxic monomers (see our post http://oecotextiles.wordpress.com/2011/10/13/polyester-and-our-health/) – the only “advantage” of using rPET is that less energy is used to recycle the already-produced PET than to produce virgin PET. And keep in mind that rPET is generally more expensive than virgin PET, so it’s a cost consideration.

24 03 2013
O Ecotextiles

I don’t know the toy industry but can only guess that virgin polyester, which is much cheaper than rPET, is chosen because of the cost. It can’t be because either polyester, rPET or virgin, is considered good for the child since they’re made of toxic monomers. So polyester is used because it’s cheap and available.

19 05 2013
Are Recycled Plastic Bottles Products Really Eco Friendly?

[…] I read the article, my eyes opened wider and wider.  How stupid was I? The article and ensuing discussion […]

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