Effects of Temperature and Humidity on Drying Time of Urushi Sap

Abstract

Urushi (oriental lacquer) sap is dried gradually and becomes hard in some ranges of temperature and humidity. The drying rate is also influenced by various factors. In this study, we studied about the effects of temperature and humidity on the drying rate of coated urushi. It was found that the logarithm of the drying time shortens in proportion to the temperature and humidity. Farther, the relation is greatly different according to the growing areas. This cause is presumed to be related mainly to the amount of the oxidation enzyme included in polysaccharide.