Effects of Fiber Materials and Fabric Thickness on UV Shielding Properties of Fabrics

An apparatus to evaluate UV shielding properties of fabrics is developed. The apparatus consists of three parts; light source, sample holder and photo sensor. Light source is UV LED of which peak wave length is 378 nm. Photo sensor is silicon photo diode. Using this apparatus, the effect of measurement condition, fiber material and fabric construction of fabrics on UV shielding property is investigated. The results obtained are as follows. 1. Distance between light source and sample does not affect UV transmittance, and UV transmittance decreases with increasing space between sample and sensor. 2. Results of investigation on the effect of fiber materials, fabric thickness and weight on UV transmittance are obtained as follows within the range of samples used here. As a whole, UV transmittance of fabrics made of synthetic fiber is large and that of fabrics made of natural fiber is small. UV transmittance decreases with increasing fabric thickness and weight. The result for thickness dependence can be regressed using exponential equation. UV protection performance per unit thickness of silk is high compared to other fibers.