Co2SD is the one bath supercritical fluid dyeing process for PET/Elastic textile, we design the dye structure containing hard segment (chromophore) and soft segment (auxochrome) to get higher dyeing fastness and design the hydrophilic copolymer through CO2-philic/hydrophilic segment ratio to give dry fit functionality, all this process without water and the used carbon dioxide can also be recycled and reused.