Tung-based coatings

When staining and/or sealing a hardwood floor, choose water-based instead of solvent-based products. They can be found in most building stores or ordered specifically at the Environmental Home Center (www.environmentalhomecenter.com). Natural finishes such as tung oil look beautiful and can be coated with beeswax, which needs to be reapplied only around once a year. 

Early coatings for appliances were slow-drying varnishes based on shellac and later on natural oils and gums. These were replaced with faster drying phenolics modified with tung oil with excellent acid-alkali and corrosion resistance ( ). With the advent of the nitrocellulose lacquers following World War I, rapid-drying topcoats became available that revolutionized the industry. 

Although the term paint has been used for latex-based systems as well as many others, traditionally it refers to one of the oldest coating systems known—that of a pigment combined with a drying oil, usually a solvent. Drying oils (e.g., linseed, tung), by virtue of their multiple unsaturation, behave like polyfunctional monomers which can polymerize ( dry ) to produce film by a combination of oxidation and free-radical propagation. Oil-soluble metallic soaps are used to catalyze the oxidation process. 

N. Thanamongkollit, K. R. Miller and M. D. Soucek, Synthesis of UV-curable tung oil and UV-curable tung oil based alkyd. Prog Org Coat, 2012,73,425-34. 

Paints, in general, are not useful for protecting buried structures, one reason being that mechanical damage to thin coatings by contact with the soil is difficult to avoid. Tests have shown that, for this purpose, their fife is relatively short. Coatings based on coal tar or on fusion-bonded epoxy have been found to be far more practical. Similarly, the usual linseed-tung oil paints are not durable for metal structures totally immersed in water, except possibly for short periods of time on the order of one year or less. In hot water, life is stiU shorter. More ade-... 

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