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Nov 04, 2024

Circular Polyester's Success Requires 'Everything Everywhere and All at Once'

What does facilitating textile circularity have to do with an acclaimed Michelle Yeoh movie? Plenty, it seems. “We’ve got to do everything everywhere and all at once,” said Karla Magruder, founder of

What does facilitating textile circularity have to do with an acclaimed Michelle Yeoh movie? Plenty, it seems.

“We’ve got to do everything everywhere and all at once,” said Karla Magruder, founder of Accelerating Circularity, a New York-based nonprofit on a mission to make textile-to-textile recycled raw materials the commercial status quo, rather than a quick dopamine hit that has trouble extending beyond pilot or capsule collection mode.

Magruder was referring to the organization’s latest report, an update on the polyester-based textile recycling trials it’s been conducting with more than a dozen collectors, sorters, recyclers, spinners, knitters, weavers, manufacturers and retailers in the United States and Europe since 2022. Compared with recycling technology development in other polymer-dependent industries, such as plastics, which have received a boost from legislative tailwinds, advancements in the textile realm still have a “long way to go.”

This remains especially true of polyester, the conventional (read: fossil-fuel-based) version of which made up 57 percent of global fiber production in 2023, according to Textile Exchange. And while the manufacture of recycled polyester ticked up by nearly 12 percent to 71 million metric tons the same year, the overwhelming majority of that is derived from discarded plastic bottles, not castoff clothing.

The trials ended up sourcing 17.4 metric tons of polyester feedstock, subjecting it to either thermomechanical or chemical recycling. Both pipelines presented challenges, signaling what Accelerating Circularity describes as the “significant systems gaps” that persist in both technology and capacity.

Thermochemical recycling, which shreds and pulverizes polyester-heavy materials before thrusting them through a thermal extrusion process to produce pellets, for instance, is a manual labor-intensive process that requires a high-purity feedstock. Recycling tests by Erema using blankets, T-shirts and laundry bags from workwear manufacturer Elis, which were selected because they had the fewest trims and required the least pre-processing, were initially unsuccessful because contaminants from imprecise cutting techniques and baling errors clogged up process filters, requiring the introduction of training and guidelines to improve feedstock quality. But even trims made with the same polymers as the main material, such as polyethylene terephthalate, a.k.a. PET, buttons, can have a different viscosity, causing them to behave differently and necessitating their removal, sometimes in a different country if there’s a time or capacity crunch.

Chemical recycling, which as its name implies, converts waste materials by altering their chemical makeup, is generally more forgiving when it comes to feedstock composition. But despite the diversity of techniques that exist—hydrolysis, pyrolysis, solvolysis, glycolysis, enzymolysis, methanolysis, gasification and depolymerization are just some of the possible options—it’s also less technologically mature and more demanding of capital investment.

One example is Garbo/ChemPET technology, which as the trials confirmed, can tolerate non-PET content up to 20 percent or more. At the same time, the monomer it produces must still be repolymerized before yarn spinning and texturizing, which can be cost-prohibitive without the economies of scale that the plastics or virgin material industry can afford. To meet minimum order quantities, the volume target of bis(2-hydroxyethyl) terephthalate—or BHET, for short—had to reach 3,000 kilograms, requiring a large amount of feedstock that needed resizing to meet specific dimensions for Garbo’s feeding system. There is a lack of standard definitions for such “de-sizing,” the report said, meaning care needs to be taken to establish a “very clear” specification of what pre-processing is required of different feedstocks.

All of which is to say that the textile-to-textile recycled polyester yarns that the trials managed to produce, as well as the resulting insights, were hard won, though there was one positive finding about how automated technology based on near-infrared technology, such as Tomra’s, can reduce feedstock loss by 36 percent compared with manual sorting. Overall, however, many of the routes available to recycle polyester are either not at full technical readiness, not supported by sorting and pre-processing at volumes required for scaled commercialization, or not supported by cost- and resource-effective waste traceability systems. This is despite the fact that regulators in the United States and Europe have voiced ambitions to tackle the mounting problem of textile waste through design directives and extended producer responsibility schemes.

“What we want people to get out of the report is for them to understand what it takes to actually build a system,” Magruder said. “I’m just banging on this all the time, but you know, so many people are so excited to say, ‘I’ve got a recycled product,’ but as you can see it’s not simple. It takes a lot of work and it takes a lot of collaboration. And if I were to take a couple of things out of this it’s that we’ve got to build the whole system if we want it to work.”

For Magruder, what this means is that companies can’t only focus on building their own “verticals.” In other words, while it’s well and good that a textile-to-textile recycler like Reju is working with Goodwill and WM to extract the polyester-rich fractions from their aggregated waste—“All these steps are good steps; the relationships are great,” she said—but what happens to the cotton fraction? Or the viscose fraction? It’s not so much thinking “bigger,” Magruder said, but thinking about the “system.”

“When you see things coming through from different people and different technologies, you’re learning something different on each one of these things, and that’s how the industry works, right? Everybody has sort of their proprietary way of doing things,” she said. “The industry’s got to get set up so it can handle all the differences. If something’s too far out of scope, it’s not going to fit in with what currently works. And those parts all have to be put together…I don’t think we have to reinvent everything. We also need to be using some of the systems that are already out there.”

Accelerating Circularity has big ambitions, which it announced at the Clinton Global Initiative’s annual meeting in September. The lessons gleaned from this recent batch of trials will inform its plans to recycle 100 tons of polyester. There are a lot of fiddly parts: capturing the right feedstock, securing it in the correct format and feeding any outputs into a preexisting commercial production process. But equally important for the industry to remember, as new technologies continue to come online, is that this is a marathon, not a sprint. This is especially true as the circular polyester space becomes increasingly crowded with buzzy new innovators—not just Reju but also Ambercycle, Carbios, Circ, Eastman, Green Machine, Re&Up and Syre.

“A lot of them have had proof of concept. Some of them have demo facilities. But these facilities, even for 10,000 tons or 50,000 tons, whatever those numbers are, they are still a couple of years down the road,” Magruder said. And I would caution people because what happens is we get fatigued. Oh, I heard about that already: ‘What’s the next cool thing?’ We have to stay engaged, and we have to do the hard work to get this going right.”

It’s like Michelle Yeoh and her parallel-universe jumping, but in a more grounded—and, hopefully single-dimension—manner. And if a metaphor that involves hot dog fingers and black-hole bagels doesn’t work for you, Magruder has another one.

“We cannot have an airport without the airplanes, without the runways, without the gas, without the food.,” she said. “Without the flight attendants, the pilots or air traffic control, an airplane doesn’t get you off the ground. It’’s the same thing. We need everything to get off the ground. We can’t have the pilot and think, ‘O.K., we’re done.’”

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