Unveiling the Future of Circular Midsole Innovation with Cirql VP Matt Thwaites

Matt Thwaites is the Vice President and General Manager of Cirql. Together with his team, they’ve launched Cirql rTPU30, the next step toward circularity in footwear.

Cirql rTPU30 is a fully recyclable midsole, and the only TPU midsole material available that includes a percentage (30%) of recycled, post-consumer TPU in the formulation. It is a patented, scalable, and moldable midsole (and outsole…see below) solution that meets all specifications and expectations for comfort, lifestyle and golf shoes.

No one is closer to this innovation or to Cirql’s mission to achieve circularity in footwear than Matt. Read on to learn why rTPU30 is potentially the first of its kind and how it can help footwear brands and consumers move toward their own sustainability goals.

Matt Thwaites OrthoLite Cirql

Why is rTPU30 a significant step in the journey to achieve circularity in footwear?

Matt: There are tens of millions of pairs of shoes thrown into landfill sites every year. It’s a massive amount of waste. A shared goal among many in the footwear industry is to keep the waste out of the landfills and to find circular, end-of-life solutions. At Cirql, we’re concentrating on two different end-of-life solutions: compostability through biodegradable products and recyclability.

rTPU30 is a recycling-oriented midsole solution that delivers exceptional comfort and performance needs. Because it is scalable, readily produced, and made from a trusted footwear material (TPU), the potential of rTPU30 to be a lower impact midsole is huge. It requires the use of less virgin TPU. And with brand-organized take back programs, it has potential to be fully recyclable into new materials.

We believe rTPU30 is the first material in the footwear industry to use GRS certified post-consumer recycled content in a midsole. Why do you think that is?

Matt: The footwear industry has incorporated recycled content from plastic water bottles in the upper materials, but midsoles pose a bigger challenge because the required specifications for footwear midsoles are very demanding.

We’ve worked hard to successfully bridge the gap with Cirql rTPU30, and to do so with post-consumer waste recycled TPU (30%). We’ve found 30% is the optimum formula to achieve the necessary hydrolysis and performance properties balance. When you consider it more closely, 30% recycled content by weight in the midsole is close to 100% by weight for an upper. That’s a lot!

Do you know what the recycled TPU content was originally used for?

Matt: Yeah, you may have it in your pocket right now! Our partner, and recycled TPU supplier, recovers post-consumer (a.k.a. used) phone cases, made from translucent TPU. They sort, clean, and pelletize the phone cases in preparation for Cirql to reuse it as 30% of our rTPU30 polymer.

Have brand partners responded to Cirql rTPU30?

Matt: The response has been very positive so far. There has been a level of amazement that we can get this amount of recycled material into a high quality and comfortable foam. There has always been a demand from the brands and the consumers, and now we have a solution that is ready to roll out on immediate demand. This product enables brand partners to increase their overall recycled content and make meaningful strides toward sustainability goals around reducing the use of virgin TPU materials.

OrthoLite rTPU30

You mention that brand partners have expressed surprise that Cirql is able to achieve this high level of quality with such a high percentage of recycled material. How does Cirql document the quality?

Matt: We have an in-house laboratory at our Cirql Center for Excellence (a.k.a. the Cirql factory), where we test the relevant parts and properties for a midsole. The machines we have onsite give up-to-the-minute, state-of-the-art readings that we can provide to our brand partners as proof we’re achieving all the necessary specs and properties.

We serve the world’s best, most technical footwear brands. They rely on our ability to create products that last and perform to the consumer’s demand. Our onsite equipment provides peace of mind and proof that we’re delivering on our promise of quality.

rTPU30 is a midsole material that can be molded to an outsole without glue. Why is this important and how does it work?

Matt: One of the challenges of end-of-life recycling is dealing with mixed materials and adhesives. We can co-mold rTPU30 foam midsole to a TPU outsole, creating a single material without any adhesives or primer. It is a fully recyclable bottom unit that eliminates the entire bonding process. Importantly, the TPU outsole is very durable and will last the lifetime of the shoe.

The manufacturing process uses less water and energy compared to conventional rubber. It is an automated, chemical-free, injection supercritical foaming process. We believe the co-molded outsole creates a lot of value for the brands and the consumer at a competitive price.

Coming full circle, so to speak, is rTPU30 a meaningful step for Cirql toward its goal of achieving circularity?

Matt: It is a very significant early step. The next step towards circularity will be to partner with brands on take back programs and recycle the midsole and bottom units into a recycled polymer and back into that brands’ midsoles. This process will give us the closed loop circularity that’s been part of our vision since Cirql’s inception.

What’s next in a potential rTPU product line?

Matt: This is just the first step toward enabling a percentage of waste to be turned into a high value finished product. There are new technologies emerging that will allow us to one day reach 100% recycled content while meeting the same performance specs as virgin materials. Stand by!


Additional Resources

Cirql rTPU30
Learn More About the Recyclable Cirql rTPU30 Midsole
The Making of Cirql rTPU30 Midsole


Comfort & Performance


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