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.
The durability of artificial marble bathtub in hot water is generally conducted on visual measurements using color difference and degree of gloss. With mechanical evaluation, on the other hand, there is no direct measurement on the surface deterioration of the test sample although there are many evaluation methods of mechanical properties such as bending strength and impact strength, which are based on measurement of the whole thickness of the test sample. In this reason, the mechanical evaluation on the surface deterioration of artificial marble was conducted using SAICAS (Surface and Interfacial Cutting Analysis System). The artificial marble is a composite material composed of the mixture of fillers whose particle size distribution is wide and the dispersion state is not homo-geneous.
The artificial marble sample used in this study was prepared with glass powders as a filler, the surface of which was treated with silane. The silane-treated and untreated samples were immersed in hot water at 90°C for given durations. Mechanical properties on the surface of the hot-water treated samples were measured with SAICAS, and the surface deterioration was examined using the value, “horizontal force (Fh)”, obtained by the measurement. Consequently, it was found that it is possible to evaluate the extent of surface deterioration on the artificial marble and the difference in the samples with and without the surface treatment with silane using SAICAS.