ARS Patents Vegetable-Based Hydraulic Fluid

April 21, 2000

A new vegetable-based biodegradable hydraulic fluid for use in heavy equipment is almost ready for market from USDA’s Agricultural Research Service. A patent on the technology has been granted. The fluid uses sunflower oil fatty acids.

Industrial scale-up production is being done in a recently renovated pilot plant at the ARS National Center for Agricultural Utilization Research in Peoria, IL. ARS chemists Terry A. Isbell and Steven C. Cermak made hydraulic fluid that contains estolides, fatty acids from high-oleic oilseeds like sunflower and safflower.

Technically, hydraulic fluids don’t lubricate mechanical systems; instead they transfer pressure in machinery to activate motion, such as a moving crane or a blade. But sunflower oil can replace petroleum-based hydraulic fluids that do not degrade well, ARS said.

Construction equipment manufacturers, like Caterpillar Tractor Co., in Peoria, began seeking biodegradable alternatives in response to tighter environmental regulations from the Environmental Protection Agency, said ARS. Other scientists at the Peoria research facility are working with Caterpillar to test biobased hydraulic fluids and biodiesel fuels in heavy equipment.

Sunflower oil estolides produce a clear fluid that pours well at below-freezing temperatures, making this hydraulic fluid desirable for engine operation during cole weather, according to Isbell.

The research was accomplished under a cooperative research development agreement with Lambent Technologies of Chicago. Lambent is seeking licensing rights to market the product commercially.