Subtle color difference between silk cloth dyed with traditional natural indigo and industrial synthetic indigo was studied using a spectrophotometer. Color difference between silk and cotton cloth using natural indigo was also examined. Color was analyzed by a CIELAB color system and compared. Results showed 1) color of silk cloth dyed with natural indigo was brighter than that dyed with synthetic indigo, 2) subtle difference in color of silk cloth dyed with indigo was affected by indigo concentration in the dyed cloth rather than by other coloring materials in dye, 3) color of silk cloth was brighter than that of cotton cloth using natural indigo, and 4) functional groups may have little influence on results in this study.
Wear experiments were conducted to examine clothing temperature(Tcl), clothing humidity (Hcl), oral temperature(Tco), sweat rate (SW), heart rate (HR), subjective feelings, and body reaction time. A Kraepelin test was performed using a sericin processed sportswear and a regular one as a control. 1. The sericin processed garment had lower values of Tco, HR and SW than the regular one. From these results, it was considered that subjects that were wearing the sericin processed garment would have a lower physiological load than subjects of the regular garment. 2. From the correlation analysis, it was found that Hcl is a very important factor in the results mentioned above. That is, it was considered that sericin processed on wear makes the moisture and water performance of the wear increase, and then the wear can make sweat evaporate smoothly. Further, the smooth evaporation can reduce the Hcl, consequently, the lower Hcl can restrain the Tco, HR and SW. Because this tendency was remarkable during and just after exercise, it was suggested that the sericin processed wear is useful when sweating. 3. Subjects who wore the sericin processed wear felt lower fatigue. However, the results of the reaction time and Kraepelin test were not significant statistically.
The results discussed in this paper are for a sound-absorption system consisting of para-aramid paper with many small holes and an air permeability of less than 30 cm3⁄(cm2·s), attached to non-woven material with a density of not more than 0.15 g⁄cm3. A combination of non-woven fabric and para-aramid paper with an air permeability of less than 30 cm3⁄(cm2·s) achieved much better sound absorption than glass wool. Although the sound absorption of the paper attached onto the non-woven fabric (RUBA®-SA) is similar to that of the micro-perforated-panel (MPP) sound-absorption system, RUBA®-SA can reduce both of the thickness and the weight of the sound-absorption system. The paper acts as the MPP, while the non-woven fabric plays the role of the air gap at the back of the MPP.
Dyeability of poly(p-phenylene terephthalamide) (PPTA) filament fibers was examined. A new type of PPTA fiber has been developed to improve the dyeability of regular PPTA fiber, which could not be dyed using the conventional ways. The water content of the new fiber could be 30% or more until being dyed. The large amount of water in the new fiber is to be enabled to dye the fiber by the conventional methods. In fact, the new fiber could be dyed with cationic dyes or disperse ones following the established ways. In the case of cationic dyeing, the obtained colors extended from pastel to deep color under the corresponding dyeing conditions.