Ford Motor Co. researchers in a patent filing this week moved one step closer to displacing petroleum with soy oil to improve rubber car parts by making them more environmentally friendly.

Their patent is for a formula that allows soy oil to replace up to 25% of the petroleum oil 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. “That’s key and part of the reason we filed a patent application.”

The process, which more than doubles rubber’s stretchability, especially is useful in applications such as 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.

“Soy-based rubber has win-win potential,” Flanigan says. “It provides superior stretchability and serves as a renewable resource that helps reduce carbon-dioxide emissions from raw materials.”

Ford’s research into soy-based rubbers 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 the petroleum-based content in rubber applications, the auto maker 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). It’s equivalent to what’s done now,” Flanigan says. “In some applications, we can take rubber and make crumb for reinforcement. But the use of soy-based rubber mostly is for cost-savings and environmental benefits.”

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.” If perfected, it’s possible the auto maker would license the process to other industries.

“It could be used in non-auto applications, including everything from footwear to conveyor belts,” she says. “A lot of companies are looking at environmental solutions.”

bpope@wardsauto.com