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tung oil,oil obtained from the seeds of a tropical tree, the tung tree (Aleurites fordii) of the spurgespurge
, common name for members of the Euphorbiaceae, a family of herbs, shrubs, and trees of greatly varied structure and almost cosmopolitan distribution, although most species are tropical. In the United States the family is most common in the Southeast.
..... Click the link for more information. family, and from seeds of some related species, all from Indomalesia or W Pacifica. It is known also as China wood oil and nut oil. The poisonous seeds found in the heart of the tung fruit (which is the size of a small apple) contain more than 50% tung oil, readily obtained when the seeds are heated, ground, and pressed. The oil is amber-colored and contains a high proportion of eleostearic acid. Because of its wide use as a dryer in varnishes and paints, it has great commercial importance. While the bulk of the product is utilized by the paint and varnish industry, tung oil has additional uses, e.g., as a component of insulating compounds and in the manufacture of linoleum and oilcloth. China was long the chief producer of the oil, but the tree has been introduced in other areas as well. The U.S. Dept. of Agriculture experimented with tung tree growing early in the 20th cent., and afterward encouraged Southern farmers to cultivate it. In recent years, an increasing portion of the commercial supply has been obtained from trees grown in the United States, particularly in the South.
(also wood oil or China wood oil), a fatty vegetable oil obtained from the seeds of the tung tree (Aleurites cordata). Tung oil constitutes as much as 70 percent of the weight of the seeds. A viscous and pungent yellowish fluid, tung oil dries rapidly in air and is soluble in most organic solvents. It has a density of 0.933–0.945 g/cu cm and a refractive index of 1.51–1.52. The saponification number is 188–197, and the iodine number is 154–176. Tung oil is composed of unsaturated acids (66–82 percent eleostearic acid, 4–13 percent oleic acid, and 9–11 percent linolenic acid), saturated acids (about 2.5 percent stearic acid and 3.7 percent palmitic acid), and unsaponifiable substances (0.4–1 percent). Such large quantities of eleostearic acid are found only in tung oil. The principal use of the oil is in the manufacture of paints and varnishes. Tung oil is mildly toxic.