Operation parameters of alpaca fiber dyeing with supercritical fluid

Abstract

Supercritical carbon dioxide (SC-CO2) was used as an alternative method of dyeing alpaca fiber. This study analyzes the colorfastness to laundering as a function of operating parameters. The fiber was subjected to a pretreatment (Impregnation), where it was soaked in an acidulated solution of Nylosan Yellow N-3RL dye, squeezed through a padder roller and then dyed in the SC-CO2 system. Dye concentrations of 4.228 × 10⁻⁴ g/ml and 13.032 × 10^-4 g/ml were tested for pretreatment and the dyeing process was analyzed using a factorial design with variables: pressure (100 and 350 bar), temperature (60 and 90°C) and time (30 and 120 min). The colorfastness to laundering reached 4.5 on the gray scale at 13.032 × 10^–4 g/ml and temperature significantly influenced the process (p-value=0.038). Colorfastness to laundering of 4 at 100 bar, 90°C and 30 min was achieved.