Where the (recycled) rubber meets the road

Tires on passenger vehicles have strict safety standards for an obvious reason: The rotating wheels are the only points of contact allowing cars, trucks, buses and motorcycles to move in a controlled manner at speeds far faster than people can run.

On the occasions when tires are scrutinized or recalled because of a manufacturing flaw, lives are at stake, and the consequences for the tire producer can extend over the course of several years.

This crucial safety aspect has long been perceived as a barrier facing the introduction of recycled-content materials into passenger vehicle tire production.

Global tiremaker Michelin, based in France with North American headquarters in Greenville, South Carolina, is clear that safety remains its highest priority. Nonetheless, it has stated it is “committed to making our tires 100 percent sustainable by 2050.”

While using recycled-content materials is not the only aspect of that sustainability target, it is part of the overall commitment by Michelin, which has made several recent investments to back up its words with actions.

Safe and sound

Sander Vermeulen, vice president of Michelin’s end-of-life rubber products recycling business, is among the people leading the effort for the tire producer to reach its sustainability targets. In addition to the 2050 target, he says, “Michelin has recently announced that we will reach an intermediate target of 40 percent sustainable materials in our tires by 2030.”

The tiremaker has been conducting research and development (R&D) and investing to strive toward those targets, but Vermeulen also is clear that compromises on safety are out of the question.

“Michelin has very strict raw materials specifications for the materials we use in our tires,” he says. “Using recovered raw materials is necessary to achieve our sustainability ambitions; but, while doing so, we are committed to maintain our high product performance and safety standards as we know them today. Michelin would never compromise safety requirements to its products in lieu of our sustainability ambitions.”

The Michelin Group makes about 200 million tires annually. Its brands include BFGoodrich, Uniroyal and the off-road brand Camso in addition to Michelin.

Along with safety and reliability issues, Vermeulen cites the volume of the Michelin Group’s business—and the large supply chain necessary to sustain it—as another reason the widespread use of recycled-content materials offers inherent challenges.

“Ensuring a consistent product performance requires consistent raw material performance, and this is where the challenge ahead is based on,” he says. “How can we ensure consistent and high-quality recovered materials supply chains in the future? This is a challenge not just for the Michelin Group but for the whole tire industry.”

As a publicly traded company, Michelin is compelled to avoid outsized financial risks caused by spending or R&D efforts that severely affect the bottom line. Partly for that reason, the company has made a series of investments and engaged in partnerships that have given it a presence in several different recycling efforts.

One of those projects includes the construction of its first tire recycling plant in collaboration with Enviro, a Swedish company that has developed a patented technology to recover carbon black, oil, steel and gas from end-of-life tires. The plant represents an investment of more than $30 million.

Based in Chile’s Antofagasta region, the plant will be able to recycle 30,000 tons of earthmover tires per year, or nearly 60 percent of these tires scrapped yearly nationwide. Work on the site begins this year, with production scheduled to get underway in 2023, according to a news release issued by Michelin.

Additionally, Michelin has partnered with Pyrowave of Canada, which uses microwave depolymerization technology to recycle plastics. Through the joint development agreement, Michelin will invest $24 million to develop an industrial demonstrator, operated by Michelin, by 2023. The tire manufacturer also has tested samples of recycled styrene produced through Pyrowave’s process in the composition of its tires.

In 2018, Michelin acquired Lehigh Technologies, a Tucker, Georgia-based company that uses patented cryogenic turbo mill technology to convert rubber from scrap tires and industrial goods into materials for new tires and other products.

Variety is the spice

Tires can be complicated products, with formulas, or “recipes,” that result from years or decades of R&D and are closely guarded trade secrets. This is one reason why recycling tires can be a difficult endeavor, becoming more difficult yet if materials extracted from scrap tires are to be reincorporated into new tires.

“Michelin’s tires are high-technology products made of more than 200 components,” Vermeulen says. “They are much more complex than they appear, which means that ensuring that all the tire’s components are sustainable presents a significant challenge. The group has always been willing to pool our expertise with that of stakeholders from different fields to accelerate progress and realize our ‘all-sustainable’ vision.”

Among the materials with the largest presence in passenger radial tires are synthetic or natural rubber, steel wire, polymer fibers and carbon black. As Vermeulen notes, these ingredients are only part of the complicated recipe, joined by various additives, resins, fillers and plastifiers.

Diversion is the mission

While the use of recycled-content materials and the lowering of carbon emissions are part of Michelin’s sustainability commitment, Vermeulen says creating infrastructure that allows tires to be diverted from landfills or improper disposal throughout in the world is another critical aspect to lowering emissions.

The author is the senior editor with the Recycling Today Media Group and can be contacted at btaylor@gie.net.