Vegetable Oils for Paint Binders
Prior to the introduction of synthetic compounds, the drying oils used for paint binders came primarily from the seeds of various plants. The most important plant sources are listed in the following table.
| Common Name/Genus and Species Family |
Description | Growing Conditions | Predominant Fatty-Acid Type |
|---|---|---|---|
| Flax | Composition of Linseed Oil | ||
| Tung, Aleurites montana Wilson and A. fordii Hemmley, Aleurites Family | Tree, superficially resembling an apple tree, to 25 feet tall. Fruits are the size of small oranges; each fruit contains five nuts. | A. montana grown in China and New Zealand. A. fordii grown in the U.S. in states bordering the Gulf of Mexico. Also in S. America. The plant is highly sensitive to climate conditions. | alpha-elaeostearic acid, which has three conjugated double bonds. |
| Soybean, Glycine soya, Leguminosae, Pea Family | Hairy, grows one to six feet. Leaves pinnately trifoliate. | Native of Manchuria. Widely grow high-protein agricultural crop. Although a legume, it is grown like a grain. Also grown as a "green manure" because of high nitrogen content. | Linolenic |
| Castor Bean, Ricinus communis, Spurge Family, Euphorbiaceae | Annual or perennial tree or shrub. Leaves palmate. Seed capsule a bur with soft spines containing three poisonous seeds. | A tropical plant, Widely grown both or the oil and as an ornamental. When grown in
temperate climates, the plant is smaller and oil yields poorer.
Warning: The seeds of this plant are highly poisonous. The poison remains in the seed cake after the oil has been pressed out. The leaves are less toxic but can cause dermititis. |
Ricinoletic, which has an isolated double bond. This acid also has a hydroxyl group, which gives castor oil unusual properties. For example, castor oil is soluble in alcohols, but insoluble in hydrocarbons. |