In the general, urethane and glasswool are susceptible to fungus attack. One of the most important preventive of fungus growth inside and over urethane and glasswool is to add fungicides in manufacturing and processing.
It is known that a black urushi film exposed to light loses its gloss. Homogenization process were applied to black urushi lacquer for improving light-resistance of urushi film. However the dryability became worse by this methods. Then in order to improve the dryability for black urushi lacquer enzyme, i.e. laccase, was added into lacquer. As a result, the drying speed and light-resistance were improved with a combination of homogenization and laccase addition. Consequently black lacquer for practical use was obtained.