Research on Dyeing and Ultraviolet Protection of Silk Fabric Using Vegetable Dyes Extracted from Flos Sophorae

This paper discusses the ultraviolet protective properties of silk fabrics using vegetable dyes extracted from Flos Sophorae. It was found that the aqueous solution of this vegetable dye has excellent thermal stability as well as stability in acid conditions. With the objective of achieving the greatest absorbency in the ultraviolet region, the following optimum extraction conditions were obtained for Flos Sophorae: extraction temperature of 100 C, extraction time of 60 min, and material to liquor ratio of 1:10. The UPF and T(UVA)(AV) values for the silk fabric dyed by the optimum dye solution were found to meet the Chinese National Standard (UPF = 69 > 30, T(UVA)(AV) = 1.07% < 5%). According to the standard, the silk fabric can claim to be a "UV-Protective product". The relation between the UPF value and the K/S value was also studied.