2003 Volume 76 Issue 4 Pages 132-137
We used protein hydrolyzate, which was obtained from hydrolyzing albuminoid by enzyme, to improve drying rate for urushi (oriental lacquer) and artificial urushi.
Suke-urushi (transparent urushi) which is a kind of the most popular urushi, was prepared by adding the protein hydrolyzate to ki-urush (raw urushi) in order to estimate drying properties of urushi at low temperature under low humidity. This suke-urushi dried at 10°C/50% RH, which meant the drying rate of urushi was improved greatly.
Meanwhile, to develop the paint by enzyme reaction using urushi as a model, that is an artificial urushi, we studied the action of enzyme laccase on synthetic urushiol analog by using the protein hydrolyzate as the third component.The enzyme is produced from culture medium of Pycnoporus Coccineus (Pycnoporus Coccineus laccase ; p-laccase), which is a wood destroying fungi, and we synthesized 4- {9' (z), 12' (z) -Octadecadienyl} catechol as an urushiol analog. This artificial urushi dried even under low humidity of 50% RH at 20°C.
Further, both the films of the suke-urushi containing the protein hydrolyzate and the artificial urushi gave broad tan δ curve and the high temperature of tan δmax in dynamic viscoelasticity, just like conventional urushi.
From above results, it forwarded greatly the promotion of utilizing urushi and the practical use of environmental-friendly paint such as urushi model.
