How green are your leggings? Recycled polyester is not a silver bullet (yet)
A colleague was standing in front of me holding a swatch of shiny black polyester made from upcycled marine litter.
“It’s recycled but is it recyclable?” I asked.
“No,” she said, “it’ll end up in landfill.” This was at the beginning of 2020 and we were at a sustainable fabric expo in London. It was just after the devastating Australian fire season that razed 18.6m hectares of bushland and just before Covid-19 relegated us to 12 months of working from home, working out at home and leaving home sparingly. A period in which office attire was abandoned and activewear was one of the only fashion categories to thrive.
Since 2019, there has been an 80% increase in activewear made from recycled polyester and searches for sustainable activewear have increased 151%. A recent McKinsey and Company poll found that 67% of consumers consider sustainable materials an important factor when buying clothing – so naturally brands are scrambling to respond. Adidas and Reebok have pledged to replace all virgin polyester (PET) with recycled polyester (rPET) by 2024, Asics has made the same commitment for 2030, Nike’s website touts products made of recycled materials and Puma has promised to scale up its use of recycled polyester to 75% by 2025.
Which all seems wonderful. Recycled polyester sounds like something that is good for the environment. It sounds like something that makes Tshirts, shorts and swimwear out of items destined for landfill. Given that the fashion industry’s colossal carbon footprint is driven in large part by insurmountable levels of waste – a 2017 report by the Ellen MacArthur Foundation found “one garbage truck of textiles is landfilled or burned every second” – it makes sense that the narrative of recycled materials would appeal to consumers.
Advocates believe this waste can be captured and recycled back into clothing, reducing the need for virgin fibres. In the case of polyester, which makes up almost 64% of the global fibre market, the hope is it will eliminate the need for virgin polyester (which is actually a common plastic derived from fossil fuels) altogether.
The reality of what the technology can deliver is a little different.
The term “recycled polyester” is used interchangeably to describe polyester made from plastic waste, like water bottles, and polyester made from discarded textiles. But because the technology for textile-to-textile recycling is still in its infancy (only 1% of all clothing is recycled) most of the recycled polyester on the market is made from “downcycled” plastic.
Francois Souchet from the Ellen MacArthur Foundation is forthcoming about the limitations of the technology. “Today mechanical recycling is mainly used to take plastic bottles and turn them into garments,” he says. Which sounds like a good thing, except that plastic can be recycled into plastic again and again. When plastic is turned into polyester, it is removed from this closed loop system. “As it is today, bottles that have been turned into garments are no longer recyclable,” says Souchet. The other notable limitation of mechanical recycling is that the fibre retains the dye colour from its first iteration, so it can only be recycled into similar colours.
Given the resource potential of textile waste and consumer demand for greener clothing, researchers around the world are working to overcome
these issues.
Chemical recycling of polyester overcomes many of the problems present in mechanical recycling, because it returns the material to the virgin quality of its original form. It does this through a process that breaks down the polyester to its raw materials, purifies them and converts them into new particles, and by removing all contamination and dyes, those materials can then be recycled on a loop. But its availability at a viable commercial scale is limited. The Japanese company Teajin launched chemically recycled polyester with Patagonia in 2005, but the collaboration has experienced difficulties since Teajin moved its recycling facility to China in 2014.
Cyndi Rhoades, the founder of Worn Again Technologies in the United Kingdom has a pilot plant up and running in the north of England where they separate cotton and polyester fibre blends, capture the cellulose for other applications and recycle the polyester to be spun into new fibres. “Our ultimate goal is to replace the use of virgin resources as inputs … because we have enough textiles in circulation to supply our annual demand for new polyester, we just aren’t effectively collecting it and we aren’t able to effectively recycle it, because processes like this aren’t yet economically viable or widely available at scale.”
She says the “demand for textileto-textile has reached fever pitch” and that because of this, “Adidas, H&M, Nike and Inditex are all moving in this direction, it’s just a matter of time.” To meet demand, the infrastructure for collecting and sorting post-consumer textile waste needs to significantly improve. This requires investment in large-scale recycling programs to increase collection rates, like incentivised drop off points, as well as technology that can detect fibre content and process high volumes of textile waste.
Currently, sorting textiles relies on manual labour, which is a problem because identifying the different fibre types in a garment is critical to the recycling process. EVRNU, a textile innovations company in Seattle, has spent the last six years developing technology that can accurately identify the different fibres in a garment using artificial intelligence and deep scanning to sort fibres quickly and with very high precision.
The co-founder and president of ERVNU, Christopher Stanev, says they shifted their focus to textile recycling of cellulosic fibres like cotton because, “fibres like lyocell and cupro can perform in exactly the same way as polyester today.” Which is interesting because unlike polyester, which may take over 200 years to biodegrade, “nature is designed to break them down, it knows how to deal with them.” He says that using the cellulose from cotton, “you can extrude fibre with the same or better performance, and you can do it multiple times and if the natural fibres do shed, they will disappear, similar to the biomass and the weeds that fall in the river and go into the ocean.”
By contrast, when a synthetic garment (eg recycled polyester, polyester, nylon or Lycra) is put through a washing machine, it sheds plastic microfibres that end up in our oceans, rivers and soil. The number of plastic microfibres entering the ocean by 2050 could accumulate to an excess of 22m tonnes and, alarmingly, a study conducted in 2015 found them in 67% of all seafood at fish markets in California.
In Australia, the National Plastics Plan, announced earlier this month, aims for “an industry-led phase-in of microfibre filters on new residential and commercial washing machines by 1 July 2030.”
Eco-activewear brand Patagonia has also been looking into microplastics since 2016 and identified that wastewater treatment plants could filter 65-92% of microfibre release. However, Souchet contests this, saying, “the microfibres are so small, the level of filter needed to capture them actually starts significantly slowing down the flow of water that’s coming through … for industrial wastewater treatment plants that’s not sustainable.” He suggests that it would be better to prevent the problem by innovating on the material side and creating fabric that releases as few microfibres as possible.
So, the holy grail is highly evolved systems for waste collection and sortation; and the creation of chemically recycled polyester that doesn’t shed microfibres. But this technology is at least several years away.
In the meantime, is polyester something we should be wearing at all? It’s a plastic, it’s a breeding ground for the bacteria that causes body odour, and unlike natural fibres it doesn’t breathe.
When I put the question to Stanev, he says “polyester is an unnatural fibre, it’s not biodegradable, it is bio-accumulative. If we need to recycle it, we can, but it’s not a good application to be used in fibres. Maybe [we can use it] in construction, cars, things we can recover that don’t leak into the water systems.”
Souchet comes at the question from a different angle, “what we need is clothing that is worn more so that we decrease the over-production and over-consumption cycle we’re in. Our reliance on polyester needs to be reduced, absolutely.”
Our ultimate goal is to replace the use of virgin resources as inputs
Cyndi Rhoades, Worn Again Technologies