Publication Type:Conference Paper
Source:Cleaning, retouching and coatings: Contributions to the 1990 IIC Congress, Brussels, p.93-97 (1990)
Keywords:acetone, ethanol, gas chromatography-mass spectrometry, hexane, lead white, oil paint, raw sienna, red azo dye, resin, solvents, synthetic dye, toluene, vermillion, wax
This article examines the effects of solvents on oil paint films. Samples of oil paint films 5, 10, and 50 years of age, containing lead white, raw sienna, vermilion, or a red azo dye as pigments, were exposed to the solvents hexane, acetone, and ethanol. The solvent extracts were analyzed by gas chromatography (GC) and combined gas chromatography/mass spectrometry (GC-MS). Changes in weight, thickness, color, and gloss were measured. Much of the extracted material consisted of free saturated fatty acids. Small amounts of free unsaturated fatty acids and their degradation products were also present. Other materials such as wax and resin were present in some samples. Synthetic dyes were easily extractable when present. The amount of extracted oil components and changes in weight, thickness, color, and gloss varied with the solvent, pigment, time of contact, and the age of the sample. Toluene, acetone, and/or ethanol produced the greatest changes. Samples containing lead white, which catalyzes the drying reactions of oil, exhibited the smallest changes. The effects of age on the oil films were not clear since the sets of samples of different age were not prepared with identical materials or according to the same formulae. The results of these and future experiments will be used to generate guidelines for the choice of solvent systems which minimize the adverse effects of solvent cleaning of paint films.