Supercritical CO2 Dyeing of Textiles: Dye Properties, Technical Requirements, and Industrial Perspectives

Supercritical CO2 dyeing represents a major innovation in sustainable textile processing, offering a water-free and energy-efficient alternative to conventional dyeing. This technology harnesses the unique solvent properties of carbon dioxide above its critical point, enabling efficient dye transport into synthetic fibers, particularly polyester, without generating wastewater or residual chemicals. For optimal performance, dyes must exhibit specific properties such as solubility in supercritical CO2, high thermal stability, strong fiber affinity, and environmental compatibility. The process requires precise control of temperature, pressure, and dye concentration, along with specialized high-pressure equipment designed for industrial-scale operation. Despite its clear ecological benefits, large-scale adoption faces challenges, including high equipment costs and the limited availability of dyes compatible with CO2-based systems. However, recent progress in dye molecular design, fluid dynamics modeling, and reactor optimization has significantly improved color yield, reproducibility, and economic feasibility. Supercritical CO2 dyeing eliminates water usage, drastically reduces energy consumption, and minimizes chemical waste, achieving high coloration performance while aligning with global sustainability goals. Its application potential now extends beyond polyester to selected blends and high-performance fibers, supported by ongoing innovation in equipment design and dye chemistry. This chapter provides a comprehensive overview of the principles, technical requirements, and industrial outlook of supercritical CO2 dyeing. It highlights how continuous advances in process engineering and green chemistry are paving the way for the broader adoption of this technology as a cornerstone of next-generation, eco-efficient textile manufacturing.