Beyond natural fibers

11 07 2012

It looks like the plastic bottle is here to stay, despite publicity about bisphenol A and other chemicals that may leach into liquids inside the bottle. The amount of plastic used to make the bottles is so enormous that estimates of total amount of plastic used is staggering. Earth911.com says that over 2,456 million pounds of PET was available for recycling in the United States in 2009. Any way you look at it, that’s a lot of bottles.
Those bottles exist – they’re not going away, except perhaps to the landfill. So shouldn’t we be able to use them somehow?
We have already posted blogs about plastics (especially recycled plastics) last year ( to read them, click here, here, and here ) so you know where we stand on the use of plastics in fabrics. All in all, plastic recycling is not what it’s touted to be. Even if recycled under the best of conditions, a plastic bottle or margarine tub will probably have only one additional life. Since it can’t be made into another food container, your Snapple bottle will become a “durable good,” such as carpet or fiberfill for a jacket. Your milk bottle will become a plastic toy or the outer casing on a cell phone. Those things, in turn, will eventually be thrown away.
So the reality is that polyester bottles exist, and using them any way we can before sending them to the landfill will prevent the use of more crude oil, which we’re trying to wean ourselves from, right? Recycling some of them into fiber seems to be a better use for the bottles than land filling them.
Plastic bottles (the kind that had been used for some kind of consumer product) are the feedstock for what is known as “post-consumer recycled polyester”. Even though plastic recycling appears to fall far short of its promise, recycled polyester, also called rPET, is now accepted as a “sustainable” product in the textile market, because it’s a message that can be easily understood by consumers – and polyester is much cheaper than natural fibers. So manufacturers, in their own best interest, have promoted “recycled polyester” as the sustainable wonder fabric, which has achieved pride of place as a green textile option in interiors.
Recycled post consumer polyester is made from bottles – which have been collected, sorted by hand, and then melted down and formed into chips, sometimes called flakes. These chips or flakes are then sent to the yarn spinning mills, where they’re melted down, often mixed with virgin polyester, and and spun into yarn, which is why you’ll often see a fabric that claims it’s made of 30% post consumer polyester and 70% virgin polyester, for example.

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 industrial scrap or old fleece jackets – we have no way to verify that. Once the polymers are at the melt stage, it’s impossible to tell where they came from. 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. 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, (until now) there was absolutely no way to tell if that was true.
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.
What does that mean? It can be assumed that the chemicals used in 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. In fact the chemicals used, if not optimized, may very well contain the same heavy metals, AZO dyestuffs and/or finish chemicals that have been proven to cause much human suffering.
It’s widely thought that water use needed to recycle polyester is low, but who’s looking to see that this is true? The weaving, however, 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 it’s widely touted that recycling polyester uses just 30 – 50% of the energy needed to make virgin polyester – but is that true in every case? 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. And finally there are issues specific to the textile industry:

  • The base color of the recyled chips varies from white to creamy yellow. This makes it difficult to get consistent dyelots, especially for pale shades, necessitating more dyestuffs.
  • In order to get a consistently white base, some dyers use chlorine-based bleaches.
  • Dye uptake can be inconsistent, so the dyer would need to re-dye the batch. There are high levels of redyeing, leading to increased energy use.
  • PVC is often used in PET labels and wrappers and adhesives. If the wrappers and labels from the bottles used in the post-consumer chips had not been properly removed and washed, PVC may be introduced into the polymer.
  • Some fabrics are forgiving in terms of appearance and lend themselves to variability in yarns, such as fleece and carpets; fine gauge plain fabrics are much more difficult to achieve.

As the size of the recycled polyester market grows, we think the integrity of the sustainability claims for polyesters will become increasingly important. There has not been the same level of traceability for polyesters as there is for organically labeled products.

But now there is now a new, third party certification which is addressing these issues. The Global Recycle Standard (GRS), originated by Control Union and now administered by Textile Exchange (formerly Organic Exchange), is intended to establish independently verified claims as to the amount of recycled content in a yarn, with the important added dimension of prohibiting certain chemicals, requiring water treatment and upholding workers rights, holding the weaver to standards similar to those 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 rights.

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: Gold standard – products contain between 95 percent to 100 percent recycled material;Silver standard – products contain between 70 percent to 95 percent recycled product;Bronze standard – products have a minimum of 30 percent recycled content.

I have long been concerned about the rampant acceptance of recycled polyester as a green choice when no mention has been made of processing chemicals, water treatment or workers rights, so we welcome this new GRS certification, which allows us to be more aware of what we’re really buying when we try to “do good”.

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Global Recycle Standard

9 09 2011

It looks like the plastic bottle is here to stay, despite publicity about bisphenol A  and other chemicals that may leach into liquids inside the bottle.   Plastic bottles (the kind that had been used for some kind of consumer product) are the feedstock for what is known as “post-consumer recycled polyester”. Even though plastic recycling appears to fall far short of its promise,  recycled polyester, also called rPET, is now accepted as a “sustainable” product in the textile market, because it’s a message that can be easily understood by consumers – and polyester is much cheaper than natural fibers.   So manufacturers, in their own best interest, have promoted “recycled polyester” as the sustainable wonder fabric, 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 ( to read them, click here, here or here ) so you know where we stand on the use of plastics in fabrics.  All in all, plastic recycling is not what it’s touted to be. Even if recycled under the best of conditions, a plastic bottle or margarine tub will probably have only one additional life. Since it can’t be made into another food container, your Snapple bottle will become a “durable good,” such as carpet or fiberfill for a jacket. Your milk bottle will become a plastic toy or the outer casing on a cell phone. Those things, in turn, will eventually be thrown away.  Even though the mantra has been “divert from the landfill”, what do they mean?  Divert to where?

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 land filling them.

Recycled post consumer polyester is made from bottles – which have been collected, sorted by hand, and then melted down and formed into chips (sometimes called flakes).

PET resin chips


These chips or flakes are then sent to the yarn spinning mills, where they’re melted down, often mixed with virgin polyester,  and  and spun into yarn, which is why you’ll often see a fabric that claims it’s made of 30% post consumer polyester and 70% virgin polyester, for example.

Polyester yarn

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 industrial scrap or old fleece jackets  – we have no way to verify that.  Once the polymers are at the melt stage, it’s impossible to tell where they came from.  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.  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, (until now) there was absolutely no way to tell if that was true.

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.

What does that mean?    It can be assumed that the chemicals used in 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.  In fact the chemicals used, if not optimized, may very well contain the same heavy metals, AZO dyestuffs and/or finish chemicals that have been proven to cause much human suffering.

It’s widely thought that water use needed to recycle polyester is low, but who’s looking to see that this is true?  The weaving, however, 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 it’s widely touted that recycling polyester uses just 30 – 50% of the energy needed to make virgin polyester – but is that true in every case?

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.

And finally there are issues specific to the textile industry:

  • The base color of the recyled chips varies from white to creamy yellow.  This makes it difficult to get consistent dyelots, especially for pale shades, necessitating more dyestuffs.
  • In order to get a consistently white base, some dyers use chlorine-based bleaches.
  • Dye uptake can be inconsistent, so the dyer would need to re-dye the batch.  There are high levels of redyeing, leading to increased energy use.
  • PVC is often used in PET labels and wrappers and adhesives.  If the wrappers and labels from the bottles used in the post-consumer chips had not been properly removed and washed, PVC may be introduced into the polymer.
  • Some fabrics are forgiving in terms of appearance and lend themselves to variability in yarns,  such as fleece and carpets; fine gauge plain fabrics are much more difficult to achieve.

As the size of the recycled polyester market grows, we think the integrity of the sustainability claims for polyesters will become increasingly important.  There has not been the same level of traceability for polyesters as there is for organically labeled products.  According to Ecotextile News, this is due (at least in part) to lack of import legislation for recycled goods.

One solution, suggested by Ecotextile News, is to create a tracking system that follows the raw material through to the final product.  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, so those manufacturer’s wouldn’t be expected to increase costs.

There are also private standards which have begun to pop up, in an effort to differentiate their brands.  One fiber supplier which has gone the private standard route is Unifi.   Repreve™ is the name of Unifi’s recycled polyester – the company produces recycled polyester yarns, and (at least for the filament yarns) they have Scientific Certification Systems certify that Repreve™ yarns are made with 100% recycled content.  Unifi’s  “fiberprint” technology audits orders across the supply chain  to verify that if Repreve is in a product it’s present in the amounts claimed.  But there are still  many unanswered questions (because they’re  considered “proprietary information” by Unifi)  so the process is not transparent.

But now, Ecotextile News’s  suggestion has become a reality.   There is now a new, third party certification which is addressing these issues.  The Global Recycle Standard (GRS), originated by Control Union and now administered by Textile Exchange (formerly Organic Exchange),  is intended to establish independently verified claims as to the amount of recycled content in a yarn, with the important added dimension of prohibiting certain chemicals, requiring water treatment and upholding workers rights, holding the weaver to standards similar to those 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 rights.

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:

  • Gold standard –  products contain between 95 percent to 100 percent recycled material;
  • Silver standard – products contain between 70 percent to 95 percent recycled product;
  • Bronze standard –  products  have a minimum of 30 percent recycled content.

I have long been concerned about the rampant acceptance of recycled polyester as a green choice  when no mention has been made of processing chemicals, water treatment or workers rights, so we welcome this new GRS certification, which allows us to be more aware of what we’re really buying when we try to “do good”.





Polyester – to recycle or not to recycle?

12 01 2011

I know it’s hard to imagine that the lovely fabric you’re eyeing for that chair – so soft and supple and luxurious – is just another plastic.

But because 60% of all polyethylene terephalate (PET – commonly called polyester) manufactured globally is destined to be made into fibers to be woven into cloth,  and because  polyester absolutely dominates the market, and because the textile industry has adopted using recycled polyester as their contribution to help us fight climate change, I think it’s important that we keep up with topics in recycling plastic.

”A Tribute to PET Bottles“ by Czech Sculptor Veronika Richterová

If using recycled polyester is good, then using “post consumer” PET bottles  is deemed the highest good.  But an interesting thing is happening with PET bottles and recycling, according to a study published in August, 2010, by SRI Consulting, which is, according to their web site,  the world’s leading business research service for the global chemical industry (www.sriconsulting.com).  The study, PET’s Carbon Footprint: To Recycle or Not to Recycle, caused more than a few ripples because it concluded that in many cases recycling bottles is no better — and could be worse — than landfilling.
The study’s key finding — widely reported — is that a recycling facility needs to recover at least 50 percent of the material it takes in if it is to achieve a more environmentally favorable carbon footprint than simply disposing directly to landfill.  The key is to improve yields , especially in sorting and to a lesser extent, in reprocessing.

This study addresses two key questions:

  • should we recycle plastics?
  • what are the carbon footprints of virgin (vPET)  and recycled PET (rPET)

In order to calculate the carbon footprint of various PET products, the study  calculated the carbon footprint for PET bottles used to package drinks from “cradle to grave,” i.e., extending from production of raw materials (primarily oil and gas) through to disposal of all wastes. The study considers a base case—bottles are used by consumers in northwest Europe, collected in a curbside system and sent on for sorting and recycling—and variations on that theme, including PET-only take-back (as currently practiced in Switzerland) as well as no recycling (with scenarios of “all landfill” and “all incineration”). Sensitivities of all major variables were assessed.

The study concludes that the curbside take-back systems are no better than landfill, in terms of carbon footprint. From a carbon-emissions standpoint, it would be just as well to bury used bottles as to recycle them, and either would be a better option than burning them.  The study found that landfilling PET bottles from certain systems rather than incinerating them could reduce carbon footprint by 30%.  Call it “carbon capture and storage” on an economy budget.  The key is to have the room – and if you read Thomas Friedman’s Hot, Flat and Crowded you may be hard pressed to agree that there could ever be anyplace on the planet with room!

SRI report author Eric Johnson told FoodProductionDaily.com that transportation and processing costs, as well as low yields of pure PET (of below 50 per cent) from curbside recycling collections such as Germany’s DSD ‘Green Dot’ programme,  warranted SRI’s conclusion. (read article here)

Johnson said: “In terms of resource squandering [of oil in particular], if it takes more resources to recycle bottles …  than to produce units from virgin PET then this is irresponsible. If you’re going to recycle…do it properly.”

Jane Bickerstaffe, director of the UK Industry Council for Packaging and the Environment, concurred with Johnson’s point that rPET purity was a significant hindrance to worthwhile recycling, given that it affected recoverable PET levels: “Quality of recyclate is a big issue because the energy costs to separate out contaminants and clean the polymer are significant,” she said. (1)

As you might expect, there was a bit of an uproar over the study.

Casper van den Dungen,  EuPR PET working group chairman,  condemned SRI Consulting’s report:  “By applying SRI Consulting’s results we would …  lose valuable [rPET] material in landfills. The model used is intrinsically wrong, as in reality landfill should be avoided as a starting principle.”  (2)

Antonio Furfari from EuPR added: “The wrong signal is that landfill is good for environment. Landfilling is not acceptable for environmental and resources efficiency reasons, and CO2 is not the only environmental variable.” (3)

And yet, Jane Bickerstaffe had this comment: “It’s worth noting that landfilling inert materials like PET is just like putting back the sand, granite etc. that was dug out of a hole in the ground in the first place.  Inert materials are benign, whereas biodegradable materials such as cabbage leaves and potato peelings generate methane in landfill and have a negative impact on climate change.” (4)

The findings of this study hinge on how the plastics are collected.  Recycling programs using curbside collection typically displace less than 50% of new PET (polyethylene terephthalate). Community programs with plastic bottle take-back, mandated separate collection, or deposits on bottles tend to report much higher displacement rates. For regions that already have a recycling infrastructure, the aim should be to boost recycled PET (rPET) displacement of virgin PET (vPET) significantly above 50%.   The key seems to be in increasing yields rather than improving collection rates.  In countries where there is no recycling infrastructure, the best choice may well be to landfill bottles.”

It seems to me that, in consideration of “should we recycle plastics”  –  the answer is (as it almost always is): “it depends”.   Should we use only carbon footprint as a yardstick?  Sometimes you have to pull back and take in the big picture; as one blogger put it, “It’s unconscionable to pay out the nose for foreign oil so that we can produce more soda bottles to package up products that make our population fat and unhealthy.”

And how does all that trash get into the oceans?  How does that figure into this equation?

Hey, I never promised answers.

(1)  Bouckley, Ben; “Plastic recycling body slams report advising countries to landfill PET bottles”, FoodProductiondaily.com, September 2, 2010

(2)  Ibid.

(3)  Ibid.

(4)  Ibid.





Issues with using recycled polyester

31 03 2010

It looks like the plastic bottle is here to stay, despite publicity about bisphenol A  and other chemicals that may leach into liquids inside the bottle.   Plastic bottles (which had been used for some kind of consumer product) are the feedstock for what is known as “post consumer recycled polyester”.  Recycled polyester, also called rPET, is now accepted as a “sustainable” product in the textile market.   In textiles, most of what passes for “sustainable” claims by manufacturers have some sort of recycled polyester in the mix, because it’s a message that can be easily understood by consumers – and polyester is much cheaper than natural fibers.

The recycled market today has lots of unused capacity – as well as great potential for growth, because the recycling rates in many high consumption areas (like Europe and the USA) are low but growing.   In Europe, collection rates for bottles rose to 46% of all PET bottles on the market, while in the US the rate is 27%.   Factories are investing in technology and increasing their capacity – so the demand is huge.  According to Ecotextile News, beggars in China will literally stand watching people drink so that they can ask for the empty bottle.

As the size of the recycled polyester market grows, we think the integrity of the sustainability claims for polyesters will become increasingly important.  There has not been the same level of traceability for polyesters as there is for organically labelled products.  According to Ecotextile News, this is due (at least in part) to lack of import legislation for recycled goods.

When you buy a fabric that claims it’s made of 100% post consumer polyester – how do you know that the fibers are 100% post consumer?  Is there a certification which assures us that the fibers really are what the manufacturer says they are?  And it’s widely touted that recycling polyester uses just 30 – 50% the energy needed to make virgin polyester – but is that true in every case?  And what about water use – it’s widely thought that water use needed to recycle polyester is low, but who’s looking to see that this is true?

Recycled post consumer polyester is made from bottles – which have been collected, sorted by hand, and then melted down and formed into chips (sometimes called flakes).  These chips or flakes are then sent to the yarn spinning mills, where they’re melted down and (if not used at 100% rates) mixed with virgin polyester.   A fabric made of “recycled polyester” has a designated percentage of those chips in the polymer.  The technology has gotten so sophisticated that it’s now difficult to verify if something is really recycled.

First, let’s look at how the recycled polyester is used in textiles, beyond the issue of whether the recycled PET yarns actually ARE spun from recycled feedstock,  because there are several issues with using recycled PET which are unique to the textile industry:

  • The base color of the recyled chips varies from white to creamy yellow.  This makes it difficult to get consistent dyelots, especially for pale shades.
  • In order to get a consistently white base, some dyers use chlorine-based bleaches.
  • Dye uptake can be inconsistent, so the dyer would need to re-dye the batch.  There are high levels of redyeing, leading to increased energy use.
  • PVC is often used in PET labels and wrappers and adhesives.  If the wrappers and labels from the bottles used in the post consumer chips had not been properly removed and washed, PVC may be introduced into the polymer.
  • Some fabrics are forgiving in terms of appearance and lend themselves to variability in yarns,  such as fleece and carpets; fine gauge plain fabrics are much more difficult to achieve.

And of course, the chemicals used to dye the polymers as well as the processing methods used during weaving of the fabric may – or may not – be optimized to be environmentally benign.  Water used during weaving of the fabric may – or may not –  be treated.  And the workers may – or may not – be paid a fair wage.

One solution, suggested by Ecotextile News, is to create a tracking system that follows the raw material through to the final product.  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!).  There are also private standards which have begun to pop up, in an effort to differentiate their brands.  One fiber supplier which has gone the private standard route is Unifi.   Repreve is the name of Unifi’s recycled polyester – the company produces recycled polyester yarns, and (at least for the filament yarns) they have Scientific Certification Systems certify that Repreve yarns are made with 100% recycled content.  Unifi’s  “fiberprint” technology audits orders across the supply chain  to verify that if Repreve is in a product it’s present in the right amounts.  But there are still  many unanswered questions (because they’re  considered “proprietary information” by Unifi)  so the process is not transparent.

But now there is a new, third party certification which is addressing these issues.  The Global Recycle Standard, issued by Control Union, is intended to establish independently verified claims as to the amount of recycled content in a yarn.  In addition to the certification of the recycled content, 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 wastewater must be treated for pH, temperature, COD and BOD before disposal;
  • there is an extensive section related to worker’s health and safety.

In the end, polyester – whether recycled or virgin – is plastic.

I came across the work of a photographer living in Seattle, Chris Jordan, who published photographs of albatross chicks which he made in September, 2009, on Midway Atoll, a tiny stretch of sand and coral near the middle of the North Pacific.   As he says, “The nesting babies are fed bellies-full of plastic by their parents, who soar out over the vast polluted ocean collecting what looks to them like food to bring back to their young. On this diet of human trash, every year tens of thousands of albatross chicks die on Midway from starvation, toxicity, and choking.

To document this phenomenon as faithfully as possible, not a single piece of plastic in any of these photographs was moved, placed, manipulated, arranged, or altered in any way. These images depict the actual stomach contents of baby birds in one of the world’s most remote marine sanctuaries, more than 2000 miles from the nearest continent.”  See more at Chris Jordan’s website here.

To make thing worse, these tiny pieces of plastic are extremely powerful chemical accumulators for organic persistent pollutants present in ambient sea water such as DDE’s and PCB’s. The whole food chain,  from invertebrates to fish, turtles and mammals … are eating plastic and /or other animals who have plastic in them.

If you’re shocked by this picture, remember that this was brought to our attention years ago by National Geographic Magazine and in reports by scientists from many organizations.  One of the things they warned us of is the Great Pacific Garbage Patch, which has doubled in size while we have done nothing.  I am shocked that we have done nothing while the cascading effects of our disposable society continue to accumulate.





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