Research on Sustainable Textile Production: Waterless Dyeing of PET and Recycled PET Fabrics

Due to water limitations and the growing global demand for raw materials, manufacturers and consumers are seeking more environmentally friendly alternatives. Polyester, a non-biodegradable fibre derived from petroleum, can be replaced with recycled polyester (r-PET), a sustainable alternative that reduces environmental impacts through the reuse of materials. The textile finishing industry, known for its high water and energy consumption, is calling for the development of low-water-consumption technologies. One innovative approach involves waterless dyeing procedures using a supercritical carbon dioxide (scCO2) medium that is particularly suitable for dyeing synthetic fibres. To assess its effectiveness, a study compared traditional water dyeing with scCO2 medium dyeing on woven fabrics made from both polyester (PET) and recycled polyester (r-PET) fibres with varying weights. After conducting tests on the dyed fabrics, the data revealed that r-PET fabrics dyed using a supercritical carbon dioxide (scCO2) medium appeared darker than fabrics dyed using traditional water dyeing techniques. Moreover, r-PET fabrics demonstrated better colour fastness. Notably, the K/Ssum values (measurement of colour intensity) of r-PET fabrics were at least as good as those of PET-based fabrics in all cases of dyeing, while the fastness values were similar for both PET and r-PET fabrics.