Study on Kinetic Behavior and Dyeability of Woolen Yarn With Madder and Cochineal Natural Dyes

In this study, kinetic behavior and dyeability of woolen yarns with madder and cochineal natural dyes were investigated. Dyeing rate was separately calculated for each dye at different times and temperatures. Results showed Patterson’s rate equation as the best model to describe dyeing rate in which rate constants in the range of 0.0031-0.0341 and 0.0024-0.0318 were obtained for cochineal and madder, respectively. Dyeing temperature had essential role on kinetic behavior and with the increase of temperature, dyeing rate and equilibrium time increased. Cochineal demonstrated better dyeability on wool than madder. Saturation point on wool was achieved using 20% and 60% owf of cochineal and madder dyes, respectively. Diffusion coefficient values at different temperatures were calculated from Hills’ equation, and it was found that temperature had key role on diffusion values. As temperature raised from 30 to 95 °C, diffusion coefficients increased from 0.83×10-11 to 7.4×10-11 in the case of madder and from 1.02×10-11 to 11.32×10-11 in the case of cochineal dye. Overall, the results of this study confirmed better dyeing performance, higher rate constant and diffusion coefficient for cochineal on wool compared to madder.