Solubility Measurement and Dyeing Performance Evaluation of Aramid NOMEX Yarn by Dispersed Dyes in Supercritical Carbon Dioxide

The solubility of various dispersed dyes in supercritical carbon dioxide was measured and, subsequently, based on the solubility data, the dry dyeing was conducted in a temperature range of 363.15−423.15 K and at pressures of 10−30 MPa. The target fibers are Aramid NOMEX yarn obtained from Du Pont, which is known to be difficult to use to perform wet dyeing, and the dispersed dyes include E-types of C. I. Dis Red 60, Blue 56, and Yellow 54 and S-types of C. I. Dis Red 360, Blue 79, and Yellow 114. Solubility data of the dispersed dyes in CO2 were correlated in terms of the density of carbon dioxide, using an empirical equation of Bartle et al. The highest color depth (K/S) of the dyed Aramid spun yarn was obtained when the experiment was performed at 423.15 K and 30 MPa. The adsorption isotherms were measured using the concentration of the three dyestuffs (E-types). These adsorption isotherms follow the Langmuir type. As a result of the supercritical fluid dyeing (SFD) for Aramid yarn with the three diffe...