Chiang Mai Journal of Science

The yellow flower of Achillea pachycephala plant, a new source of natural dye, was introduced and its dyeability on wool yarn fibers was studied. Central composite design (CCD) and response surface methodology (RSM) have been applied to design experimental runs to evaluate the interactive effects of the operating variables. The four independent numerical variables which were dye concentration of Achillea pachycephala, mordant concentration, acid concentration, and dyeing procedure time at boiling temperature was selected according to the preliminary experiments. The effect of these variables was examined on the color strength (K/S), brightness, chroma and yellow coordinate of dyed yarn samples as dependent factors. The samples dyed with Achillea pachycephala flowers were presented a yellow shade. The ANOVA results of the quadratic model was indicated that the dyestuff concentration (A), mordant concentration (B), and dyeing procedure time (D) were the significant independent factors on the color strength of dyed wool fiber with Achillea pachycephala, due to their less probability values and their interactions such as AB, AD, A2, B2 were significant model terms. Increase in mordant and dye concentration led to higher up take of dye molecules (according to the K/S of dyed sample), and presented a higher chroma value. Moreover, the presence of mordant in the wool fiber was enhanced the fastness properties of dyed samples.