The castor bean plant yields high-quality oil suitable for plastics manufacture, cosmetics, polyurethanes, synthetic detergent, inks, lacquers, paint strippers and varnishes. Pharmaceutical castor oil use includes expectorants, anti-dandruff treatments and emulsifiers. Castor oil products make fine lubricants for high-temperature engines in jet aircraft and racing cars, as well as hydraulic fluids and automotive grease. Castor oil may also have uses as a renewable biofuel resource.
In 2010, Evogene Ltd., an Israeli biotech company, announced that castor bean cultivars for semi-arid production could bring 25 million acres in Texas and Brazil into biofuel production. Field trials are planned in partnership with Texas A&M University and Brazil’s South Cone Agriculture. Evogene projects that when grown on marginal or arid land, castor bean biodiesel could reduce greenhouse gases by 90 percent in the United States and 75 percent in Brazil when compared to conventional diesel.
In 1831, olive and almond oils were treated with sulfuric acid to create the first synthetic detergents. In 1875, less expensive castor oil replaced them. The detergents were used in the process of dying with chemical pigments, and castor oil detergent was most efficient in dying with a pigment called Turkey Red. Sulfonated castor oil will completely disperse in water and can be used as an emulsifier, anti-foaming agent and humectant, or moisturizer.
Lipstick is usually 50 percent castor oil by weight. The castor oil forms a durable, shiny surface film after application and remains solid at temperatures up to 122 degrees F. Castor oil derivatives make nail polish flexible after drying, and prevent cracking. In moisturizing creams, castor oil is an emollient that support skin repair and permeability.
Polyamide 11, a castor oil product, is a highly flexible nylon used in the manufacture of rubber hoses and tubing. Dehydrated castor oil is used in paints and varnishes. Castor oil acts as a plasticizer when added to urethane to create polyurethane. Sebasic acid from castor oil is used the production of polyester and is added to antifreeze coolants. Toothbrushes and some fishing line are made of Nylon 6/10 from sebasic acid.
Highly toxic ricin occurs naturally in castor beans. Ricin is water-soluble and remains in the bean "cake" after oil is pressed and extracted. Cooking does not destroy ricin, so castor bean cake is not used as livestock feed.
Castor beans are as much as 48 percent protein, with a complete amino acid profile and trace elements such manganese, copper and zinc. The cake is 4.5 percent nitrogen, 1.5 percent phosphorous and 1.5 percent potassium, making it ideal organic manure. Ricin in the manure kills nematodes.