Study on the Dyeing Performance, Color Gamut, and Anti‑Ultraviolet Properties of Silk Fabric Dyed with Gnaphalium Affine Extract

This study utilizes Gnaphalium affine extract as a natural dye to color silk fabric, aiming to enhance the ultraviolet (UV) resistance. The UV-Vis spectrum was employed to confirm the types of pigment components present. Through single-factor mordanting experiments, the influence of dyeing process parameters on the dyeing performance and color characteristics was investigated. The adsorption behavior and coloration mechanism of the dye on tussah silk fabric were discussed. The color gamut, color value, color fastness, and anti-UV performance of the dyed fabrics were evaluated. The results indicate that post-mordanting with Al3+ and Fe2+ ions constitutes the most effective dyeing strategy. The optimized process parameters were determined to be a dyeing temperature of 90°C, a duration of 40 min, a dye bath pH of 3, and a mordant concentration of 5 g/L. Under these conditions, the chroma (C*) and hue angle (h°) reached 29.36 ± 0.9 and 66.19 ± 0.7, corresponding to the orange region. Al3+ post-mordanting produced a pale brownish-yellow tone, whereas Fe2+ treatment resulted in a darker brown hue. Of the 23 differentiated color samples, 19 showed strong agreement with the Pantone color system, indicating good international applicability and potential for standardization.