The Relationship between the Change in Urushiol by Repetitive “KUROME” of the Urushi Liquid and Natural Drying Property Occurring in a Low Humidity Environment

Kisuke NAGASE, Yukio KAMIYA, Kengo HODUMI and Tetsuo MIYAKOSHI*

Department of Industrial Chemistry, School of Science & Technology, Meiji University; 1-1-1 Higashi-Mita, Tama-ku, Kawasaki-shi 214-8571 Japan

We examined the repetitive “KUROME” of raw urushi in a reaction vessel for the purpose of refining the polymerized urushi liquid that has a natural drying property in a low humidity environment. Namely, we evaluated the polymerization apparatus of the urushi liquid as a simple experiment. The raw urushi was polymerized by the repetitive “KUROME” process in a traditional method. We also examined the change in urushiol and the drying property in a low humidity environment (20--25 °C, 45--55%RH).
Raw urushi undergoes enzymic oxidization by repetitive “KUROME” and decreases the urushiol monomer. Also, in this reaction, we developed a relation formula because there is a correlation in the area of the reaction vessel base, processing quantity and also processing time. Furthermore, with these changes, it was determined that the hydroxy value and anti-oxidization power decrease and the autoxidation of the side chain more easily occurs.

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