Circularity critical to solving the sustainability conundrum

CHARLOTTE, N.C.—If the tire industry is going to get sustainability right, it has to get every part of sustainability right. Not just in the composition of the tire, but the performance and end life as well.

Because sustainability without circularity or practicality yields nothing more than fancy tires.

"I would say that many of us in the industry can make a 100-percent sustainable tire right now. It will hold air, it will hold a vehicle," Russell Shepherd, director of technical communications at Michelin North America, said during the Smithers' Traction Summit July 26. "The real goal is to make a 100-percent sustainable tire with ISO performances—if not better—at a cost that our customers and our consumers can afford."

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That is an incredibly tall order. But it is one that Michelin—as well as other major tire makers industrywide—are committed to doing. Last summer, Michelin marked a significant step forward on that journey, saying it had produced a racing tire that contained 46-percent sustainable and recycled content. In June, Michelin stepped closer to its sustainability targets, touting a race tire with 53-percent bio-based and recycled content that was used in the running of 24 Hours of Le Mans.

The achievements largely resulted from the increased use of natural rubber and recycled carbon black recovered from end-of-life tires. Other sustainable materials used in the tire included citrus rinds, sunflower oil, pine resin, and recycled steel and aluminum.

But Michelin also is determined to meet its aim of 100-percent sustainability, according to Shepherd's co-presenter, Jason Stravinski, CEO of Michelin-owned Lehigh Technologies. And 100-percent sustainability, Stravinksi said, must involve full circularity.

"Half of the path is sustainability, but there is the other half of the path, which is circularity," Stravinski said during his presentation at the Traction Summit. "So as we start to judge things that are sustainable, I ask the question: Is it circular?

"I am a big fan of cacti and dandelion roots, all those sorts of things," Stravinski said. "And it's important in terms of emerging technologies around sustainability, but it doesn't solve circularity.

"So when you look at circularity, we talk about things like micronized rubber powders, recovered carbon black and pyrolysis," Stravinski said. "And the holy grail would be complete and total devulcanization where we sever the sulfur bonds, keep the carbon chain intact, and we are full circular. If you figure that out, you will be rich."

Lehigh Technologies, a producer of micronized rubber powders made from recycled rubber, has become one of those important circular, sustainable pieces for the tire industry, among others, Stravinski said.

And Lehigh's product—which goes to market under the PolyDyne brand—has been proven to be a replacement for petrochemical derived products. Further, Stravinski said, it has proven to be successful in uses throughout the tire, from the tread to the sidewall to the beading.

Right now, Stravinski said, there are truly sustainable solutions—materials and technologies—that are emerging industrywide. And when those solutions are identified and verified, he said, they need to be fully embraced.

"Why is it that we have an existing solution in the marketplace and we are not using it to its full potential?" Stravinski asked. "… Because, frankly, it's 2022. And 2030 is, like, tomorrow. And by the time we adopt something to get to a sustainable material rate by 2030, well, we (should) have started two years ago. Because we are going to have to use multiple solutions to solve this problem."

Building a truly sustainable tire will take more than just one or two breakthroughs, he said. An all-sustainable tire is going to be expected to perform optimally, mitigate costs for consumers and maintain a full carbon-neutral footprint throughout its life cycle. And the industry can't do all of that, Stravinski said, without fully embracing the best, newest products and ideas.

"Existing technologies—and when I say existing technologies, I mean when emerging technologies become existing technologies—current, existing technologies need to be used to their full potential. They need to be," Stravinski said. "Because we are going to (need) 10 or 11 of them. We can't have just one, because we are not going to win the war."

Stravinski, like Shepherd, also contends that solutions tire makers find in the quest for fully sustainable products, cannot be solutions for solutions sake. Because without all of the sustainability components working together for circularity, performance and cost, the only thing you've done is create a fancy tire.

"(Every) sustainable solution cannot impact performance and cost. It can't. We can't make that trade-off," Stravinski said. "And so we have to find creative solutions that give us both. I also believe that solution needs to fix the circularity problem. It needs to fix the end-of-life tire waste problem."