Energy Level and Chemical Class of Disperse Dyes—Plausible Characteristics of Level Dyeing Performance

The level dyeing index (LDI) is a measure of dye performance influenced by the dye migration process, ensuring the maximum uniformity of dye redistribution onto the fabric surface. The current study evaluates the level dyeing performance on polyester according to the energy level (low and high) and chemical classes (azo and anthraquinone based) of the three disperse dyes studied. The best levelness was obtained using C.I. Disperse Red 73 (an azo-based, low-energy level disperse dye), which exhibited the highest migration index (MI%) value. LDI results were obtained from the ratio of the exhaustion at the critical dyeing temperature (E _CDT % and the final exhaustion E _f %), and the migration index (MI%). Each dye's LDI can be used to determine the compatibility of disperse dyes for combination dyeing.