High temperature pressing techniques, such as ironing or calendering, changes the surface structure and luster of fabric as well as the shape and properties of fiber and yarn, and results in a change of fabric properties. The effect of high temperature pressing on the thickness and air permeability of fabrics is studied in this paper. Cotton and wool fabrics were chosen as the experimental materials. Significant differences in the change of those properties were observed among them. In relatively heavy cotton fabrics, both properties, the thickness and the air resistance, were varied nearly in proportion to the experimental parameters, that is, finishing temperature, pressure and time. However, temperature among parameters was most effective. The strong negative correlation was observed between thickness and air resistance, that is to say, the air resistance varied inversely with decrease of thickness, which shows the graph of quadratic equation. In wool fabrics, little corelation between the air resistance and the thickness was observed, although the air resistance was changed with the experimental parameters. This is considerd to show that a complicated variation of the fiber shape and the yarn cross section occurs during the finishing. In the case of the calendering treated under very high pressure, air resistance is approximately in direct proportion to the temperature even in light fabrics such as cotton broad or nylon taffeta.
In this study, transmission of UV rays through the sheet samples piling up two different cloths (sample-1/sample-2) was investigated. Here, the sample described before slash ( / ) denotes the sample on the side of incident beam, and one after slash ( / ) does the sample on the other side. The results obtained are as follows. 1) The total UV transmittance through sample-1/sample-2 was different from one given by the product of the transmittance of sample-1 and sample-2. 2) When the sample-1 has a higher UV transmittance than the sample-2, the sample-1/sample-2 showed a lower value of total UV transmittance than the sample-2/sample-1. 3) Both the total transmission and reflection factors were very close to values predicted from a theory which the authors have established. The authors introduced a mechanism that UV ray reflects many times between two samples. 4) Using the theory, the apparent reflection factor of piled samples with two different materials is evaluated by the reflection factors of individual materials. 5) It was found that the total transmittance of two piled sheets decreases with increasing the ratio of the transmittance factor of samples on the incident beam side to that on the other side.