Influence of Fabric Constructional Parameters and Thread Colour on UV Radiation Protection.

The purpose of the research presented was to analyse the influence of the fabric surface cover factor and fabric colour values on the degree of UV ray transmittance and the UV protective factor (UPF). The research was carried out on lightweight coloured fabrics woven in sateen weave with different densities of warp and weft threads and with different colours in the weft. Measurements of the UPF were performed using the "in vitro" method in the range of UVA and UVB ray wavelengths, from 280 to 400 nm. The results of the research confirm the importance of the fabric surface openness for the UV protective factor and expose the influence of the fabric face and reverse sides as well as of colour values L*, C*_ab, h_ab of warp and weft threads on the UPF in sufficiently closed woven constructions. Namely, constructions with less than the 5% surface openness offer excellent protection (UPF above 50), whereas constructions with less than 10% surface openness offer good to very good protection (a UPF above 20). At coverage higher than 95%, the fabrics analysed could be generally divided into three groups with respect to the effectiveness of their UV protection: fabrics of darker colours (black, blue) with extremely high UPF values,fabrics of chromatic lighter colours (yellow, red, green) with UPF values half of those of darker colours in general, and white fabrics (bleached) in which the desired UPF values are not reached regardless of the degree of the cover factor. [ABSTRACT FROM AUTHOR]