PAINTS Paint is an old use for soybean oil but unless treated, soybean oil is only a semi-drying oil, because it contains insufficient poly-unsaturation to dry or cure to a non-tacky state. Thus soybean oil alone made poor paint and was largely limited to extending linseed oil in periods of linseed shortages. The development of soybean oil alkyd resins in combination with soybean oil improved drying, adherence, endurance, and colour. After World War II, oil-based paints lost market share to less expensive and easier to use latexes (rubber-based) using water as the solvent and lower levels of soybean oil-derived ingredients. By far, the most important application for soybean oil in paints and coatings is as alkyd resins. Normally, the oil and a polyol (for example pentaerythritol) are reacted by a process known as alcoholysis, or trans-esterification, to transfer some of the fatty acids from the soybean oil triglycerides to form esters with the polyol. Alkyds can now even be made water-dispersible. One should, however, not forget that oil-based paint is a declining share of paints. Advances is biotechnology are encouraging molecular biologists and soybean breeders to contemplate redesigning soybeans to produce more useful oils (for example with conjugated fatty acids and epoxy fatty acids) that could expand soybean oil's share of the coatings market.