Characterization and evaluation of rubber (Hevea brasiliensis (Willd. ex Juss) Mull. Arg.) seed oil as drying oil in varnish and finishing oil

Rubber seed contained 49.4-57.5% crude fat and 14.0-17.9% crude protein. The rubber seed oil (RSO) showed a low saponification number (174 mg/g) indicating the presence of long chain fatty acids. RSO was composed predominantly of unsaturated fatty acids (89.92%) such as linoleic acid (40.24%), oleic acid (32.16%) and linolenic acid (17.52%). The effect of storage on extracted RSO was also determined. The oil was stored for two months at room temperature and at 4 deg C, with and without purging with nitrogen. Results showed that there was no significant change in iodine number for all storage conditions. On the other hand, peroxide value and free fatty acid were significantly affected by temperature, storage time and purging with nitrogen. Oils containing unsaturated fatty acids are prone to hydrolytic deterioration. However, there was no detectable change in the fatty acid composition of RSO after two months of storage. RSO and linseed oil (LSO) were used as component in almaciga varnish formulations and compared with the commercial lacquer. The almaciga formulations dried faster than the commercial lacquer and exhibited higher gloss values. On the other hand, both the varnish formulations and the reference varnish showed strong adhesion, high resistance to hot-and-cold check test and strong resistance to hot coffee and cold soft drinks. However, the reference lacquer showed greater resistance to 45% ethanol. The prepared formulations showed low resistance to 45% ethanol because almaciga resin is soluble in ethanol. Rubber seed oil as finishing oil was also compared with formulations using linseed oil. The formulations dried faster than the commercial finishing oil (CFO). Furthermore, formulations with lower oil content gave shorter drying time. The formulations and CFO were both resistant to hot coffee, cold soft drinks and 45% ethanol. On the other hand, immersion of the yemane wood specimens to cold and hot water resulted to loss of luster, dulling and whitening of the finished surface. Based on the performance and characteristics of RSO, it can be recommended as a substitute for linseed oil in varnish and finishing oil manufacture