Adidas’s new Futurecraft.Loop sneaker claims to have achieved a holy grail of sorts for the fashion and footwear industries.

For years these businesses have been talking about finding ways to “close the loop.” That basically means creating a product, selling it to a consumer, and then when the consumer is done using it, recycling 100% of the material back into a new product.

This goal, and concept, is a response to growing consumer awareness that the staggering volume of clothes and shoes these industries produce each year gobbles up huge quantities of resources, only to wind up sitting in landfills after being discarded. A growing share of that stuff is made of plastic, which doesn’t biodegrade. Companies try to find ways to recycle their products, but the technical ability to do so just hasn’t been there.

Now Adidas says it has figured out a way to do it, at least in one specific context: a performance running shoe. And the great innovation was to make it—from sole to upper to laces—out of a single material. It’s a thermoplastic polyurethane, or TPU, that the company created.

Adidas “100% recyclable.”

It sounds like such a basic, obvious solution. But this change, which allows the entire shoe to be ground up, melted back into raw material, and used for new products without any waste, also represents a surprisingly complicated technical accomplishment that was at least five years in the making.

“I think it’s a big achievement from a product-creation perspective, in that it’s never been done before,” said Paul Gaudio, Adidas’s global creative director, at a presentation in New York where the brand unveiled the Futurecraft.Loop. “It’s outwardly very simple. It looks simple. It’s made out of one material. But behind the curtains it’s extremely sophisticated.”

The challenge of a 100% recyclable shoe

There are shoes on the market made of just a couple materials, but they’re not performance running shoes—a specific category of sneakers that have been engineered over decades from different specialized materials to make them lighter, stronger, and bouncier.

Early athletic shoes were leather with a rubber sole (and some retro fashion sneakers still are). Then companies devised foams—soft plastics filled with small air holes—to add cushioning. Eventually the uppers became synthetics, including materials such as Nike’s Flyknit and Adidas’s Primeknit, both woven from stretchy synthetic yarn. Each new material innovation led sports companies to find ways to integrate them and make a more high-tech product. Today, the average performance running sneaker uses 12 to 15 different materials, Gaudio says.

That material mix is part of the reason a running shoe can’t be easily recycled. The materials would all have to be separated, or one might contaminate the recycling process of another. It’s not possible to separate certain fiber blends, and some items, such as cotton, can’t yet be recycled without a substantial loss in quality.

The challenge of making a running shoe from a single, easily recyclable polymer is that it needs to replicate the functions and performance of all those other materials you’re trying to replace. That’s what Adidas says it has done on the Futurecraft.Loop.

Like most running sneakers, the shoe is a jumble of textures. It has a knit upper that looks and feels like woven polyester, except in spots where it turns into a more rigid material to provide support. The midsole is fused pellets, resembling styrofoam. A stabilizing torsion bar in the midsole is a hard, moulded plastic, while the outsole is tough but flexible. The laces replicate the look of cloth, and the insole has a knit pattern on the top but a material like pressed plastic pellets on the underside.

Marc Bain/Quartz The middle photo shows the textures on the insole, and the photo on the right shows the torsion bar.

Each form of the polymer has its own purpose, and represents its own set of technical obstacles. “The upper itself, it’s meant to be comfortable. It needs to provide support. It needs to be breathable. It needs to form to your foot,” Gaudio explains. “Being able to develop the material in a way that can be processed through a knit machine was a huge challenge—and it still is, especially as you start to recycle the material. It requires development of the machines themselves. You can’t just expect this material to work on existing machines.”

The midsole of the shoe is Boost, a cushioning created by the chemical firm BASF that has been a signature in several of Adidas’s top sneakers for years. Gaudio calls it Adidas’s “gold dust,” and so the companies had to remake it using the polymer used in the rest of the sneaker. “That’s completely different,” he says. “It’s a foaming process. It’s more of a chemical process than a yarn-making process. That’s working with different machines again, different manufacturers, different [materials] suppliers.”

And then you have to put all these things together, which traditionally means attaching the upper and midsole with glue—except smearing glue all over the materials can also contaminate them and make them unfit for recycling. The Futurecraft.Loop uses no glue at all. A few years ago, when Adidas was developing its robotic Speedfactory, it devised a way to fuse components without glue, which is messy and slow to dry, as part of its goal of automating as many processes as possible.

That innovation, created for an entirely different purpose, helped Adidas unlock a way to make its recyclable shoes. “That was, I would say, the moment when we realized we got this figured out,” Gaudio says.

And challenges still to overcome

While Adidas might have had an easier time beginning with a casual shoe, it started with a running sneaker specifically because they tend to get worn out and therefore discarded faster. The shoe is also a proof of concept; if Adidas can make a 100% recyclable technical shoe, it can do it with a simpler lifestyle shoe too.

Adidas Made for running.

The Futurecraft.Loop, though, is still in “beta” mode. Adidas hasn’t yet released it to the public, opting instead to give out 200 pairs to what it calls “leading creators” in cities around the world. It handed out pairs to everyone in attendance at the New York launch (full disclosure: I received a pair as well), though the shoes, in a sense, are just on loan. Adidas wants everyone to wear them, run in them, and then return them—probably with some Instagram shots posted along the way—with feedback. Adidas will use what it learns for its next generation of shoes. Right now, it’s planning a commercial release for spring 2021, though it will keep releasing small numbers of Loop products in the meantime. Adidas hasn’t said what those products will be, or whether they are all sneakers.

The company is also still figuring out exactly how it’s going to go about the recycling process, from the way it will collect used shoes to how it will reuse the material from them. Just 10% or less of the material in the first generation of Futurecraft.Loops will go into the sneakers’ second generation. The rest, the company says, will be used in other 100% recyclable, yet-to-be-announced Loop products. It’s a big caveat, and as Gizmodo pointed out, “not exactly what everyone might have in mind when they see the ‘100% recyclable’ tag featured on the laces of the first-gen Loops.”

“The reason for this percentage is due to current production technology, and the fact this is a performance running shoe,” explains Graham Williamson, senior director of Adidas’s Future team. “We are creating totally new processes and innovating our way out of the global problem of waste but we are at the start. We could have waited until we are at our goal of a performance shoe being created from 100% recycled materials but we will get there faster if we collaborate and show the world the journey we are embarking on.”

Adidas is also making its new Loop products from all or mostly virgin polyester. Maybe the biggest problem the fashion and footwear industries have is that they simply produce too much stuff. Even if the industry is making more sustainable products, those products themselves are using more resources and creating more carbon emissions.

But Adidas says it’s a necessity for now, as it figures out the possibilities for future generations of Loop items. “Our focus is ‘Let’s start with the virgin material,’ just because of the challenges,” Gaudio says. “It’s not contaminated. It’s the easiest to work with. And then we’ll start the cycle of degradation and reuse.” For now, the reused polymer might only be suitable for certain components. It might not be able to be knitted into uppers, but it could work for outsoles.

Adidas The Loop.

Adidas is studying how it can overcome those limitations, and potentially even start making Loop products from recycled plastic. In 2015 it partnered with the group Parley for the Oceans to start making shoes from plastic collected from oceans and shorelines. Could it start using that reclaimed plastic to make fully recyclable sneakers? “You can believe we’re working on that,” Gaudio says.

The company expects to scale up its Loop products on roughly the same timeline as its Parley project. This year it intends to release 11 million shoes made of ocean plastic.

Goals yield solutions

Though Adidas still has a number of problems to solve, it doesn’t need to learn the answers all at once. Sometimes change is incremental. One of fashion’s recognized leaders in sustainability, Eileen Fisher, has proved that point in its business. It set its goals first, and then figured out how to achieve them along the way.

Adidas is setting off on a similar path. It also frames the Futurecraft.Loop as a way to prompt other companies into action, and to hopefully provoke some innovative solutions to major problems that don’t belong to any one business.

“This product, and this kind of a process, is an invitation to the big industrial partners to also get on board with the program and begin to help solve the problems—for us but also for them,” Gaudio points out. “If I’m a big plastics manufacturer, I’m nervous. This is a moment in time where everyone’s realizing that ‘Wow, all that stuff we make doesn’t go away.’ And they need to help solve it. Our role in this is to show that it can be done, and to show people that it can be desirable, it can be valuable, it can be purposeful. If that’s the case, then consumers come, business comes, partners come, suppliers come, solutions come.”