Ethylamine adduct (30 Kg) was prepared in an industrial field by reaction of ethylamine with epoxydized soybean oil, oxiran content 6.5, and identified by infra-red spectroscopy. The prepared adduct was emulsified using both polyoxyethylene sorbitan monooleate in the continuous medium and sorbitan monooleate in the dispersed medium, using high speed homogenizer, 4000 round per minute. Surface tension measurements were determined by platinum ring technique. The stability of the prepared emulsions was determined thermally. The emulsified adduct was scaled up to 1/4 ton using 50 L capacity homogenizer. The emulsified adduct was added to emulsion paint formulations by three different concentrations. Physical, chemical, mechanical, corrosion resistance, water uptake, and weight loss tests had been done in absence and presence of the corrosion inhibitor, to evaluate the corrosion inhibition efficiency of the emulsified adduct. Chosen formulations were scaled up to 5 ton using a 100 L capacity mixer. Carbon steel plates of 15x 15 cm were coated and exposed to natural weather on the roof of National Research Center. The effect of the emulsified ethylamine adduct as corrosion inhibitor was followed up by taking pictures every month for more than 2 years. It was found that the prepared ethylamine adduct was successfully emulsified and could protect steel from corrosion. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 174182, 2010