Study on Making Temperature and Formation Processes of Persian Resin-Oil Coating of “Kaman Oil”

"Kaman Oil" is one of the essential protective coatings of artworks in Iran, based on the old texts. It is made from diterpenoid resin and linseed oil at boiling point. This product's making method and temperature have always been discussed in various sources. Accordingly, this article aims to investigate temperature and chemical changes occurring in its production to obtain a standard product for use in traditional art. Therefore, according to the literature, three resins of Moroccan Sandarac, Colophony and Manilla Copal, and linseed oil were selected to produce "Kaman Oil." Thermal analysis of DSC and TG/DTA was used to examine changes in product properties during the heat treatment for different amounts of resin and oil. Finally, the chemical changes were studied with Fourier transform infrared spectroscopy. The result shows that the making temperature mostly depends on the oil changes and occurs between 380-390°C. Also, demethylation, aromatization, and decarboxylation reaction appeared at these temperatures to form the final product.</em>