Oriental Lacquer

The oriental lacquer is prepared from the sap of the “varnish tree” Rhus verni-ciflua, which is an emulsion of an aqueous phase and an organic phase called urushol. The urushi fraction consists of a mixture of catechol derivatives substituted in 3-position with aliphatic C₁₅ or C₁₇ side chains. About 60% of these side chains are trienes. The structure of the trienes is similar to that in linseed or tung oil and is essential for the effectiveness of the oxidative curing of oriental lacquer. We have utilized new techniques and used combinations of modern techniques to analyze the urushiol mixtures and to characterize and identify each individual compound. We have also developed ultraviolet stabilizers for oriental lacquer, stabilizers that could be incorporated into the polymerizing mixture during the curing process to result in ultraviolet stabilized oriental lacquer.