EV surge brings greater demand for rubber

HOUSTON—The evolution toward electric vehicles means the amount and type of rubber used in the automotive sector will continue to change.

More than a generation has passed since Toyota first mass produced the Prius hybrid and the next generation expects to see a huge tilt toward completely electric vehicles.

But widespread electrification means the roles rubber now plays will evolve, Bill Hyde, executive director of olefins and elastomers for IHS Markit, said during the company's recent World Petrochemical Conference.

"If you are a pure electric (vehicle), you need a lot less rubber parts. You don't need nearly as many hoses and gaskets, those sorts of things," he said when asked about the future role of rubber in automotive applications during the virtual conference. "That, on the increment, says less synthetic rubber demand.

"But the big deal, obviously, is in the tire—and the impact on the tire is going to be significant. One of the things they will be looking to in order to extend the range of the batteries—they will be looking at perhaps even harder than we have been from just a pure fuel-efficiency standpoint—is lowering rolling resistance," Hyde said.

This, he said, "means shifting from emulsion styrene butadiene rubber, or ESBR, into solution-styrene butadiene, which allows different sorts of compounding," he said.

Only using batteries to power vehicles adds more weight compared with use of internal combustion engines, Hyde said. "So you need to have stiffer sidewalls. In order to accomplish that, they actually, perhaps, add a little natural rubber into the compounding to make it a little stiffer.

"From an aerodynamic standpoint, we'll see a lot less of these wide tires and wide, lower-profile tires and a lot more back to the thinner tire, because it has less air resistance to it," he explained.

"So all in all, we think as we move toward more hybridization, it's probably a little less synthetic rubber per passenger car tire, a little more natural rubber. But the more significant impact is going to be on the shift of what kind of synthetic rubber is going to be used," he said.

While the use of rubber is expected to diminish during the move to electric power, there is a tradeoff highlighted by the pandemic that could help maintain rubber demand through increased personal vehicle use.

"There's less willingness to take public transportation as an example. The people who are commuting are less likely to want to get on a subway or a train. So there's gives and takes with that," Hyde said. "There's offsets to that (expected demand decrease)."