Ford Motor Co. researchers move one step closer to replacing petroleum with soy oil to improve rubber auto parts by making them more environmentally friendly.

Ford's formula, contained in a patent filing, enables soy oil to replace up to 25% of the petroleum typically found in rubber parts. The process also promises greater performance in some cases, says Cynthia Flanigan, Ford technical leader in elastomeric polymers.

“We are targeting the same equivalent performance (of traditional rubber) in terms of properties, but one of the unusual aspects we got is much better elongation,” Flanigan tells Ward's.

The process, which more than doubles rubber's elasticity, is useful especially in door seals, she says. Soy-based rubber also could be used in radiator deflector shields, air baffles, cupholder inserts and floor mats, all of which are being considered for future Ford vehicles.

Ford's research has been under way for about three years and is being partially funded by the United Soybean Board.

One discovery sees soy fillers replacing “carbon black,” a petroleum-based material traditionally used to reinforce rubber. Together, soy oil and soy fillers could replace up to 26% of petroleum-based content in rubber applications, Ford says.

But although the use of soybeans, a renewable resource, is considered more environmentally friendly than petroleum, soy-based rubber offers little advantage when it comes time to recycle a vehicle. “There's no advantage for using the soy in rubber for the end-of-life (processes),” Flanigan says. “It's equivalent to what's done now.”

The International Rubber Study Group says the auto industry accounts for more than 50% of worldwide rubber consumption, which exceeded 24.2 million tons (22 million t) in 2008 and is expected to rise more than 4% through 2013.

Flanigan says Ford has no timeline to use soy rubber in production vehicles, but research “has been promising.”