Abstract
Oriental lacquer needs a long time to hardening, because an enzyme reaction is usually involved. In this study, the rapid hardening reaction of urushiol, which is the main component of the lacquer, was examined from a basic viewpoint at the high temperatures. The hardening reaction was carried out at a temperature within the range of 100∼200°C under an air atmosphere and a nitrogen atmosphere. Next, the behavior of the viscosity for styrene and urushiol was examined at high temperature as a function of time in order to understand the reaction mechanism. The hardening rate and viscosity increased with temperature. These tendencies for urushiol were more apparent under air. On the other hand, those for styrene did not depend on the atmosphere. These facts suggest that the hardening reaction of urushiol is not conducted only by simple radical polymerization.
