From steam power to laser power: Resource analysis of direct surface heating for textile dyeing

Colouring fabric using aqueous dyes is the most resource-intensive step in conventional textile manufacture, as it indirectly heats the whole textile through steam chambers or boiling vats to achieve equilibrium dye adsorption/desorption between the fibre and the liquor, reaching equal concentration and fixation of dye throughout the polymer fibre. Direct laser heating of the textile surface can achieve the necessary dye fixation, but this has only been demonstrated at a laboratory scale. This paper evaluates a prototype production process in a UK textile factory. A Continuous Wave CO2 laser was used to fixate 1.5 % Nylosan Red F4BL dye onto a 16.5 % elastane, 83.5% Nylon 6, 16 mm width woven, 724 gsm narrowband fabric. Life Cycle Inventory Analysis results compare the original steam-driven vat dyeing to direct laser surface heating and report a reduction of 172.8 to 30.4 litres of water per kilogram of product and 77.9 to 11.5 megajoules of energy per kilogram of product. Commercial standard tests verified that permanent dyeing without degradation of the fibre structure was achieved. The reported efficiency gains of this manufacturing technology are discussed to identify product lifecycle impacts, including improvements to current production chains, such as relocating manufacturing closer to retail.