The aim of this study was to verify whether the JIS L 1919 A-1 testing method for soil resistance and release of textiles in soil particles is suitable for hygienical evaluation. The sample consisted of 12 different types, each with four different fiber materials and three different colors. We prepared soiled fabrics using artificially soil particles by JIS L 1919 A-1, and soiled fabrics were evaluated by visual colorimetry using grayscale and color measurement, as well as weight measurement. Then, we examined the relationship between the grade of soil resistance and release, the color difference (ΔE), and the weight of soil particles adhering to the test piece. The results show that there is a significant correlation between the grade of soil resistance and release as measured by visual colorimetry and the color difference (ΔE), which is an aesthetic evaluation index. By contrast, there was no correlation between the grade of soil resistance and release as measured by visual colorimetry and the weight of soil particles adhering to the test piece, which is a hygienical evaluation index. Therefore, it was shown that the hygienical evaluation by existing evaluation methods of visual colorimetry using grayscale has a limited scope of application.

The direct-resinification of the curdlan was attempted via the hot-press compression molding, controlling the water content in the starting curdlan powder as well as the molding conditions (i.e. temperature, pressure, processing time). By adding water to the curdlan powder so as to have the water content be around 22 wt%, the hot-press compression molding to resinify the curdlan powder could be made in the temperature range of 180–190 °C, which was convenient to fabricate the hardwood fiber-curdlan resin composites, suppressing the thermal decomposition of the wood fibers. When the hardwood fiber-curdlan resin composites were molded at 190 °C, the stress-strain curves sometimes exhibited a strain at break larger than 5 %. The addition of free water would promote the hydrolysis of curdlan molecules, and as a result the mobility of the molecules could have been enhanced. Further, the free water in the curdlan resin might have worked like a plasticizer. However, the strength of the curdlan resin decreased inevitably, compared with the data when the excess water was not added to the curdlan powder.

In processing synthetic fiber yarn, the drawing rollers draw the synthetic fiber yarn by running the rotation speed difference between multiple rollers. Meanwhile, the flow around the roller changes as the yarn runs on the roller at high speed, affecting the windage loss power. Therefore, it is effective to simulate the air flow using computational fluid dynamics (CFD) analysis to reduce both windage loss power and costs. However, when analyzing the windage loss power using CFD, if the cross section of the yarn is modeled as a circle, the contact part with the roller becomes point contact; thus, it is difficult to divide the model into meshes. Therefore, in this study, we investigated a CFD analysis model of yarn that is close to the actual phenomenon and considers the calculation cost. Consequently, we found that the model that reproduces the yarn in a strip shape to reduce the calculation cost is inappropriate as an analysis model because the flow field and the windage loss power are different. In addition, even if the cross-sectional shape of the yarn was changed from square to circular, the flow field and windage loss power remained unchanged.