Soybean flour may one day help keep your beverages cold at home and on the road.

Fu-Hung Hsieh, a University of Missouri-Columbia biological and ag engineer, has developed a soybean-based rigid polyurethane foam that looks promising as an insulation component for chest coolers, soft drink machines and refrigerators.

"The soybean components make the polyurethane foam firm, strong and stable under a humid and hot environment," explains Hsieh. "We're very optimistic about the commercial adoption of our product and the potential it has for increasing the market for soybeans."

Hsieh notes that, if the soy-based foam captures 20% of its market, 1 million bushels of soybeans a year will be needed to meet the demand.

Walt Rupprecht is optimistic that the production of soy-based water- and chemical-blown foams could eventually use over 2 million bushels of soybeans annually.

Rupprecht is the plastics commercialization manager for Omni Tech International, the Midland, MI, company that provides technical support to the United Soybean Board's (USB) New Uses Committee.

"Products made with soy-based insulation could be on the market by late 2000," says Rupprecht.

Supported by USB and Missouri Soybean Merchandising Council funds, Hsieh has spent about five years studying the feasibility of using soybeans as an additive in polyurethane foams.

In his earliest work, he used pure soybean protein. It helped make good foam, but wasn't cost-effective.

Soy protein costs $1.50 to $1.60 per pound, says Hsieh. By contrast, soy flour costs around 20 cents per pound. Polyols, conventional polymers, cost 70-80 cents per pound.

In addition to its lower price, soy flour has good dimensional stability, says Hsieh. Dimensional stability - rigid foam's ability to maintain shape - is crucial.

For example, chest coolers are made of polyurethane foam sandwiched between two thin layers of plastic. The foam gives the cooler its shape, so if the foam distorts, the lid won't fit.

The soy-based foam is environmentally friendly, too. During the high-speed mixing process, Hsieh uses water as a blowing agent instead of hydrofluorocarbons, which can damage the environment.

Polyurethane insulation made with soybean products doesn't emit the volatile organic compounds that sometimes are produced with other types of polymers, such as formaldehyde resins, according to USB. That may be an important consideration for structural applications such as insulation panels.

The light-yet-rigid properties of soy-containing foam lend themselves to other applications, including sporting equipment and flotation devices for boating.

Hsieh is also studying ways to boost its density. Higher-density foam could be used in a wide range of products, including car bumpers, he says.