Investigation of Eco-friendly Dyeing of Para-aramid Using Supercritical CO2

In order to solve the problems of dyeing difficulty and serious pollution of traditional water-based dyeing of para-aramid, supercritical CO2 fluid was employed as a dyeing solvent to dye para-aramid yarn (temperatures 80-120 degrees C, pressures 16-24 MPa, dyeing time 15-90 min, and dye concentration 1 %-7 % o.m.f.). The K/S values reached 2.07 and 1.91 at 120 degrees C, 24 MPa, 60 min, 5 % o.m.f., and a CO2 flow of 20 g/min with C. I. Disperse Red 54 and C. I. Disperse Blue 79, respectively. The results proved that para-aramid yarn could be dyed in supercritical CO2 fluid. Moreover, the thermal and mechanical properties of dyed para-aramid yarns in supercritical CO2 showed a slightly increasing trend. The washing, rubbing, and the light color fastness of the dyed samples were rated above 4-5, and the color fastness durability of the dyed para-aramid was also presented good.