Petroleum fuels your morning run as much as coffee and oatmeal. The footwear industry relies on the goopy lifeblood of plastic, and running shoes in particular are dependent on the stuff.
For runners to do their job—stabilize your foot, soften impact, and give enough bounce—the typical shoe ends up being constructed from almost entirely plastic and foam.
From lace loops to decorative decals to stiff outer soles and cushy innards, running shoes are an intricately manufactured stew of acronyms: TPU (thermoplastic polyurethane), EVA (ethylene vinyl acetate), and PET (polyethylene terephthalate).
“It’s a crazy material,” says Sebastien Kopp. “A running shoe has to have flexibility, strength, and memory; plastic is the best and cheapest material to do that.”
Kopp is a cofounder of Veja, a French shoe company that built its popularity on fair trade practices and sustainability. Its new shoe, the Condor, is the company’s first performance runner—and a hard-won lesson in just how difficult it is to make a shoe without plastic.
Veja bills the $150 Condor as the first “post-petroleum” running shoe, though that claim is a bit of a stretch. The shoe still has plenty of virgin plastic in it, much to its makers’ frustrations.
Biobased Plastics – Advantages & Disadvantages
Chemical Recycling – Advantages & Disadvantages
What is Circular Packaging? Watch Now!
Compostable Plastics – Advantages & Disadvantages
Plastics Recycling – Advantages and Disadvantages
Approximately 53 percent of the Condor is made with bio-based and recycled materials; the remaining 47 percent is virgin plastic and rubber. It’s a number that Kopp says is an honest, if improvable, entry point for a running shoe made by a self-funded company.
Veja is up against bigger, more established sportswear and clothing companies that in recent years have rolled out their own version of “eco-conscious” sneakers. Some, like Everlane and Allbirds, are making casual shoes from sugarcane and recycled plastic that are meant for padding around the city, not running a 10K.
Others, like Adidas’ shoe made from recycled ocean plastic and Reebok’s 100 percent recyclable sneakers made from cotton and corn, get a little closer to what Veja is envisioning with the Condor.
The Condor is designed for long runs, but not for serious marathon racing. “That’s an entirely different kind of shoe,” Kopp says. The goal was to incorporate more bio-based ingredients while ensuring that the shoe could reliably pound the pavement for a couple of years without falling apart. T
hey quickly realized that replacing virgin plastic was much easier in the shoe’s superficial components. A mesh upper made entirely from recycled plastic bottles comes in gray, white, neon yellow, and black.
The brand’s signature V decal is constructed from 100 percent castor oil, while the lining on the inside of the shoe is made from organic cotton and recycled plastic bottles.
The guts of the shoe were a little trickier. Making running shoes is a lot like baking, says Arnaud Dabir, a project manager at Veja who worked with material scientists on the shoe. Each component is a precise mix of ingredients that must blend together for the end product to work.
“Sometimes innovation isn’t inventing something new, it’s rethinking thoroughly established processes,” he says. “Think of a gluten free chocolate cake—you take off a few classical ingredients and add new ones. In the end you still have a chocolate cake, as good as or better than the other ones, but made in a different way.”
There’s the outsole, the hard rubber exterior that provides durability and grip; and the inner sole, a firmer insert that gives structure to the shoe and cradles the foot.
Sandwiched between the two is the midsole, the cushy layer of foam that provides support, absorbs impact, and gives the shoe a springiness.
All of these components are commonly made from plastic, and every company has its own tightly held recipe for its foam’s fit and feel. The secrecy is understandable—a slight tweak to the formula can result in major energy savings and faster times for runners.
The Condor is less performance-based than something like Nike’s marathon-ready kicks, which meant Veja could experiment with some of the materials in its sole.
Kopp says Veja’s material scientists spent three years searching for a mix of ingredients that would create a strong outsole that wasn’t pure synthetic rubber.
In the beginning, they tried using 100 percent wild rubber tapped from the Amazon, but found the shoe was too heavy. Adding air to the natural latex made it lighter but far less resilient.
“The sole would last for five runs and then it would give into the weight,” Kopp explains. Veja landed on a mixture of 30 percent wild rubber, 39 percent synthetic rubber, and 31 percent rice husk that makes the sole light but firm.
The midsole, too, is a combination of bio-based and synthetic materials. Fifty-five percent of the midsole is made from regular EVA—a modern, if environmentally destructive, marvel of material science known for its lightweight bounciness.
For the other half, Veja created a bio-based foam made from banana oil (for flexibility), rice husk (for firmness), and sugarcane, the latter of which is quickly becoming a common replacement for petroleum-based materials like EVA.
“What’s great about sugarcane is that it’s not different than the regular EVA,” Dabir says. “We have the same benefits and limitations.” For the insole, Veja concocted a mixture of regular EVA, jute, wild rubber, recycled plastic bottles, and recycled EVA that comes from the scraps generated during production. “In the recycling process, the EVA loses a part of its qualities, so to maintain the high level of performance, we limited its share to 8 percent,” Dabir added.
The end product is still a shoe made with plastic, but less so than before. This incremental approach is the most realistic—and honest—way to banish virgin plastic from the shoe production cycle, Kopp says. “We like for everything to be transparent, even the limitations,” he says. Veja is already working on its next iteration of its running shoe, but when I ask how the next generation will differ from the first—will there be more sugarcane? How much more sustainable could it get?— Kopp shrugs off the question.
“The best way to prevent greenwashing is to talk about the present,” he says
Published on wired.com