Whereas some alternative rubber sources are on the verge of commercialization, others have been used in tires for years, according to Kedar Murthy, vice president and general manager of Atlanta-based Lehigh Technologies Inc.
"What some people call crumb rubber, we call micronized rubber powders," Mr. Murthy said.
Micronized rubber powders (MRPs) are what Mr. Murthy called "a second chemical revolution — doing something with the waste we've created."
MRPs are an old industry as far as recycling goes, around for the last 30 years, according to Mr. Murthy. "But we've take a different approach," he said.
Boasting the unique "Cryo Turbo-Mill" micronizing technique it acquired in 2006, Lehigh has an annual capacity of 60,000 metric tons of MRPs at its six production lines in Atlanta, ranging from 20 to 200 mesh, according to Mr. Murthy.
Lehigh has the only R&D center dedicated to MRP chemistry and development, and six of the world's 10 largest tire makers use Lehigh MRPs, Mr. Murthy said. More than 450 million tires worldwide have been manufactured using Lehigh MRPs, he said, without going into detail.
Nearly 40 percent of Lehigh's revenue is in non-tire products, such as plastics, asphalt, construction and oil field products, Mr. Murthy said.
"In the past two to five years, there has been fairly broad adoption of MRPs at 5 to 7 percent," he said.
At the current state of development, Lehigh MRPs can comprise 5 percent of a tire's rubber content comfortably, or up to 10 percent allowing for considerable adjustment of the compound.
"As you use more, you get more cost savings," he said. He showed a chart demonstrating that a facility manufacturing 10 million tires annually and using 5 percent MRPs can save more than $2.7 million annually.
The big change in the tire market today is that tire makers are developing protocols for optimizing the use of recycled materials, up to 10 percent per tire, according to Mr. Murthy.
There was a fear of using recycled materials in new tires, Mr. Murthy said, but developments such as Bridgestone's using the Ecopia brand name for its line of low-rolling-resistance tires are symbolic of shifting attitudes.
"Things are starting to change, but very slowly," he said.
R&D or business leadership, corporate sustainability goals and a commitment to sustainable technology are all necessary to accelerate the adoption of recycled materials in tires, according to Mr. Murthy.
However, just about every major tire maker is making these efforts, he said.
Some of the examples include Yokohama Rubber Co. Ltd.'s doubling its use of recycled materials between 2008 and 2016, or Sumitomo Rubber Industries Ltd.'s introducing eco-friendly Enasave tires, which the company claims are made entirely without fossil fuel-based resources.
MRPs are now common ingredients in new tire development and high-performance tire manufacturing, and the MRP supply chain is well-established, according to Mr. Murthy.
"Expanding the use of MRP or any new material requires continued development of technology and supply chains globally," he said. "Creating a supply chain for any new material requires a mindset change by the tire company."