Changes loom in NR future as tire makers build more sustainable supply chains

There's sustainable. And then there's more sustainable.

When it comes to natural rubber, one of the tire industry's most prevalent raw materials, it's all about taking that already sustainable resource and finding ways to make it even more sustainable.

For some of the world's biggest tire makers, there are two ways to do that: You can address the way you source, harvest and procure hevea NR. Or you change your natural rubber plants.

Some—like Bridgestone, Goodyear and Continental A.G.—are doing both and really focusing efforts on the latter. They're developing alternative natural rubber sources from desert shrubs (guayule) and dandelions. Others, including Michelin and Hankook Tire & Technology Co. Ltd., are more focused on the former—exploring ways to ensure more sustainable cultivation, harvest and procurement of hevea NR.

"Part of our definition of 'sustainable' is that it has to be renewable," said Russell Shepherd, technical communications director for Michelin North America Inc. "Natural rubber is, naturally, renewable. … But if you go and chop down trees in a forest, which have been there for 200 years, that doesn't meet our standards. When we look at the total picture we are very conscious, again, of producing natural rubber and extending the life of the plants. Even the way we cut the rubber tree is designed to keep that rubber tree productive for as long as possible."

One of Michelin's most recent investments saw the French tire maker take full ownership of a sustainable natural rubber pilot project in Indonesia. That project, Michelin said, oversaw the planting of 23,000 hectares rubber trees and preserved 39,000 more hectares from agroforestry activities and subsistence agriculture.

That same project, Michelin said, has created 4,000 jobs, offered training services to farmers and helped improve living standards for 50,000 inhabitants.

"All of that is part of making natural rubber continue to be a long-term, sustainable, renewable source," Shepherd said.

Hankook, likewise, has taken steps to help ensure a more sustainable NR industry. One of those initiatives involved a partnership with Project TREE (Transparent Rubber Ecosystem for Earth), a blockchain-based traceability system that helps to track the sourcing of natural rubber in Indonesia.

"Through this project, Hankook Tire was able to upgrade the quality of natural rubber and solve issues such as deforestation and environmental destruction," said Rob Williams, Hankook Tire America Corp.'s senior vice president of North America sales.

But Hankook isn't just looking at supply chain transparency, it's stepping up to help smallholders ensure healthy crop yields.

"Earlier this year, Hankook Tire donated 6,000 liters of formic acid to more than 100 natural rubber farmers in West Kalimantan, Indonesia," Williams said. "This eco-friendly coagulant can reduce damage to trees and lower the risk of water pollution while providing safer working conditions with lower toxicity and less irritation."

But neither Michelin nor Hankook are embarking on their journeys alone. Both are members of the Tire Industry Project, a global forum focused on addressing sustainability issues industrywide. The voluntary CEO-led initiative also involves Bridgestone, Continental, Goodyear, Kumho, Sumitomo, Toyo Tires, Yokohama and Pirelli.

Collectively, through TIP, the goal is to identify and address sustainability concerns—those that affect people or the planet—as they relate to the life-cycle impacts of tires. And that includes a focus on building more sustainable NR supply chains.

For Bridgestone, the future of the natural rubber industry looks an awful lot like guayule.

The tire maker's interest in guayule as a North American source of natural rubber dates back more than a decade, but Bridgestone stepped up its investment in guayule cultivation and material development in 2014.

That's when it opened its Biorubber Process Research Center in Mesa, Ariz. The 10-acre campus allowed the tire maker to focus its R&D efforts.

Since 2014, Bridgestone has invested more than $100 million in the research and development of guayule NR.

And in August the company's plans for guayule got a whole lot bigger. The tire maker earmarked $42 million to establish commercial operations around guayule as it works to grow partnerships with Native American tribes and U.S. farmers to expand the cultivation and harvest of guayule by 25,000 acres.

This year alone, Bridgestone hopes to expand its partnerships to add as many as 350 additional acres of guayule crops.

"We're extremely bullish on the potential for guayule as a domestic source of strategically critical materials, such as rubber, hypoallergenic latex, building material adhesives and renewable fuel, just to name a few," Nizar Trigui, Bridgestone Americas' chief technology officer and group president of Solutions Businesses, said in a statement when the investment was detailed. "We're thrilled to be taking this major step toward commercialization before the end of the decade."

Bridgestone said it expects to invest further in these efforts beginning as soon as 2030.

As it turns out, sustainability may be in the eye of the beholder.

Because while some look at dandelions and see problematic weeds, Continental sees much more. Potential, for one. More sustainable supply chains for another.

The Hanover, Germany-based tire maker is betting big on dandelion rubber as an alternative source of NR. Dandelion rubber, known as Taraxacum kok-saghyz, is the heart of the tire maker's Taraxagum Project, which looks to cultivate and commercially scale the NR for use in tires of all kinds.

"The primary focus of our Taraxagum Project is to reduce long transport routes of natural rubber from its current area of origin—mainly southeast Asia," said Claus Petschick, head of sustainability for Continental Tires. "So we are working on replacing natural rubber from trees with natural rubber from dandelions."

Continental already has made some strides in replacing hevea natural rubber with dandelion-derived rubber. Those successes take shape with Urban Taraxagum, a bicycle tire in which all of the natural rubber is derived from dandelions.

Urban Taraxagum is a very solid first step in a journey toward developing more products with domestically sourced, alternative natural rubber. Continental envisions ways to tap the potential of the natural rubber by incorporating it more frequently into products ranging from passenger tires to truck tires.

"We have already built passenger car and truck tires, which proved to be equivalent in performance to tires made from conventional natural rubber," Petschick said.

As proof of that continuous journey, Petschick pointed to the Conti GreenConcept tire that made its debut at IAA last year. That tire, he said, used dandelion rubber in the compounding.

And it was just one element that helped it to stand out as a sustainable product.

"(GreenConcept) contains more than 50-percent recycled and renewable raw materials and provides an outlook to where we are heading to mid-term (and) on our way to our target to use 100-percent sustainable materials in all our tires by 2050," Petschick said.

Goodyear, meanwhile, may have two viable alternative natural rubber options at its disposal.

The tire maker is looking very closely at the viability of dandelion rubber as an alternative rubber source, and it has committed millions of dollars to related research and development efforts.

In April, the Akron-based tire maker said it planned to work with Cincinnati-based Farmed Materials Inc. to help research and cultivate a commercially viable source of dandelion rubber. The initiative launched this spring with the planting of dandelion crops in Ohio.

Goodyear noted that the "multi-year, multi-million-dollar" dandelion research effort is supported by the U.S. Department of Defense, the U.S. Air Force Research Lab and BioMADE.

"Global demand for natural rubber continues to grow, and it remains a key raw material for the tire industry," Chris Helsel, Goodyear senior vice president of global operations and chief technology officer, said in statement when the partnership was announced. "This is a critical time to develop a domestic source of natural rubber, which may help mitigate future supply chain challenges."

And when it comes to domestic sources of NR, Goodyear may have an avenue to explore guayule as well.

The acquisition of Cooper Tire & Rubber Co. brought into the Goodyear fold some significant expertise and experience in the development of guayule as a natural rubber source for tires. Cooper previously received a $6.9 million U.S. Department of Agriculture grant to join in the guayule research efforts. From there, the Findlay-based tire maker heavily invested in research and development of guayule for a five-year period.

During that time, Cooper served as the leader in the consortium and developed several concept tires for passenger cars using guayule. The team found that the 100-percent guayule-based concept tires performed at least equal to tires made with hevea and synthetic rubber. The tires also performed significantly better in rolling resistance, wet handling and wet braking than their conventional counterparts, Cooper said.

At this point, it appears that Goodyear is leaning more heavily toward dandelion rubber as the promising alternative source of natural rubber. But, as Chief Sustainability Officer Ellis Jones notes, Goodyear is open to solutions that help it establish a more sustainable future and develop products that optimize safety, performance and life cycles.

"We think about the impact of climate change in that region, in Southeast Asia, and think about the resiliency of the supply chain. We want to make sure we have another source of natural rubber," Jones told Rubber News. "(Cooper's) material science team is with our material science team, so that is something that they will look at. We think dandelion rubber is it. But with Cooper coming on board, we will take a look at their science behind it."