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Best of Both Worlds: Unlocking Synergies of Mechanical and Chemical Recycling

There appears to be an unfortunate misunderstanding in parts of the industry that chemical recycling is a substitute to mechanical recycling, when in fact they are both (on their own or in combination) highly relevant technologies to enable the industry to become less dependent on virgin materials. In this article, four companies—Recover™, Renewcell, Worn Again Technologies and Circ—all share ideas on how chemical and mechanical recycling technologies are actually complementary and can work in synergy to achieve a circular fashion system. Starting around 10 years ago or so, a wave of new developments for next-generation chemical recycling technologies* for textiles swept across the industry, promising solutions that would allow the industry to become circular, at last!

Many have since presented very encouraging results, producing recycled garments or capsule collections created with recycled fibers and with at least one currently scaling to industrial capacity (Renewcell). However, most aren’t yet operating at an industrial scale and won’t be for the next couple of years due to the extensive time it takes to progress from lab scale to first industrial plant. It means that for the time being, these technologies cannot yet achieve the significant circular impact the industry is so desperately waiting for.

These upcoming chemical technologies became the go to solution for the industry, as they held the promise to overcome several of the issues associated with mechanical recycling, which was often described as a downcycling solution in conversations and reports. As these new solutions lay on the horizon, large parts of the industry overlooked mechanical recycling as an effective textile-to-textile recycling solution. This was a shame because the technology was already available and could be scaled relatively easily.

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Almost a decade later, most of the chemical recycling technologies are still working to establish commercial scale. Learning more about these new technologies over time, we find that chemical tech indeed has great benefits, but is very different from mechanical recycling. Making the case for chemical to replace mechanical therefore seems not only unlikely, but also not smart. While the urgency of the climate crisis and the need for a circular textiles industry has never been greater than at this very moment—‘IPCC [intergovernmental Panel on Climate Change] signaling a code red for humanity’—a new vision is proposed. One where mechanical and chemical tech work in synergy in a vision we can start now.

“We are all united in our aim to create a circular fashion industry and I do believe we need both technologies to achieve this goal,” said Helene Smits, CSO Recover™. “Mechanical tech can keep cotton in the system longer for a few rounds of recycling. Then finally, when the cotton fibers have become too degraded, we can regenerate all these fibers with chemical recycling into man made cellulosic fibers that can be used again.”


Pros, cons and synergies

So what are the differences between chemical and mechanical recycling and how can they complement each other to create a circular fashion system?

The big advantage of mechanical recycling of cotton is its impact. It uses no water or chemicals and only limited energy. According to the Higg Material Sustainability Index and results calculated using the Higg MSI ( V3.2, the global warming potential of Recover™ recycled cotton is almost 10 times less than virgin conventional cotton. Recover™ recycled cotton produces just 0.199 kg CO2 eq (global warming potential), compared to organic cotton (0.998 kg CO2 eq) and conventional cotton (1.93 kg CO2 eq).

Another great advantage of mechanical is that it’s a versatile and proven tech that already exists and is available now at scale, offered by Recover™ for example. Recycled cotton fibers can be easily blended with virgin cotton (or other carrier fibers) in varying quantities to allow for the optimal cost/performance balance that brands require, and it can help achieve the sustainable cotton targets that many brands have set for 2025.

Finally, several of the chemical recycling technologies, including Worn Again Technologies and Circ, also focus on the recycling of cotton/polyester blends, the most common blend on the market. The fibers are separated, and cotton is recaptured as MMCFs while the polyester is broken down into monomers or recaptured as polymers. Mechanical tech can recycle blends, but it does not separate the fibers. This is perfectly workable for certain blended feedstocks and for certain applications, but not for all.

“In our view, it’s not an either or situation,” said Cyndi Rhoades, founder Worn Again Technologies. “Mechanical recycling can play an equally valid role in the portfolio of circular solutions while chemical or ‘regenerative’ recycling can ultimately enable the replacement of virgin resources, to address future resource constraints and help to deliver the industry’s net zero greenhouse gas emissions target by 2050.

“We are all united in our aim to create a circular fashion industry and I do believe we need both technologies to achieve this goal” —Helene Smits, Recover™

There are of course several other specific advantages and disadvantages related to the different recycling technologies that we are not able to dive into now. Considering the large variety in quality and composition of textile waste feedstocks, and the variety in requirements (in terms of quality, cost and impacts) for recycled fiber applications, there is not only space but also a need for multiple recycling solutions to complement each other to achieve the holy grail of circularity. Ideally, these solutions are not only complementary, but can even work together in synergy to create highly effective recycling hubs and hybrid products where outputs from different technologies are combined.

“We see a major synergy opportunity in combining mechanically recycled cotton with chemically recycled MMCs to achieve a feel, quality and price that offers a direct substitute to virgin cotton fabrics in significant volumes,” Harald Cavalli-Björkman, Chief Growth Officer, Renewcell. “It offers a path to shifting not just MMC but also cotton demand to 100% circular and biodegradable textiles at massive scale.”

Changes in regulation and consumer preference are increasing the demand for recycled content in the fashion industry. This will help improve the economics of both mechanical and chemical recycling and should support both parts of the industry.

We do expect that there will be competition between some of these technologies in their race to secure the right feedstock for their plants. Several plants with capacities of 30,000 to 60,000 tons are planned for the coming 5 years and they all need feedstock. With the growing problem of ‘textile waste’ we are currently dealing with, this seems like a future scenario we can look forward to.

“Collection and sorting of waste textiles will be a core component of fashion’s circularity,” said Luke Henning, CFO Circ. “Sorting, will generate different streams of waste that will need to be recycled, be it wool, acrylics, nylon, cotton, polyester or blends thereof. Rather than shipping all these streams out to different locations, it may make sense to locate the different recycling technologies together. Creating recycling hubs could produce economic and product synergies that could increase the recycling rates.”

For the most part this will be a game of economics, however, we might want to consider planning for the most circular scenario as much as we can. A proposed scenario here could mean that we apply the ‘lower footprint’ mechanical recycling first to cotton textile waste for one or two rounds. In this way, we can keep true cotton properties in the system longer with minimal impact. When the cotton fibers become too degraded, we can regenerate these fibers with chemical recycling into ‘regenerated’ MMC fibers. A key enabler of such a scenario will the widespread implementation of material ID and product tracking systems.

Helene Smiths Recover
Helene Smits, chief sustainability officer, Recover Courtesy

This article was written by Helene Smits (CSO, Recover) in collaboration with Cyndi Rhoades (Founder, Worn Again Technologies), Harald Cavalli-Björkman (Chief Growth Officer, Renewcell) and Luke Henning (CFO, Circ).