Ecofriendly Dyeing Strategy Based on Dyeing Kinetics and Thermodynamic Analysis for Melt-Spun Polyurethane Fibers

Melt-spun polyurethane fibers (MSPUFs) have garnered popularity owing to efficient production methods and exceptional stability. However, the development of the MSPUF has been restricted by challenges such as poor dyeability as well as energy and cost concerns associated with the dyeing process. Herein, we devised a highly efficient dyeing technique that operates at a lower temperature and a shorter duration. In comparison to conventional dyeing methods, our novel approach reduces the temperature from 98 to 75 °C, while reducing the amount of dye utilized by 25% and the dyeing time by 50%. In this method, the modifier increases both the positive charge and the amorphous zone of the fiber, while rational dyeing conditions are designed based on thermodynamic and kinetic analyses. This strategy enabled a 76.3% increase in E% and a 45.9% increase in K/S values at reduced temperatures and a shorter time while simultaneously improving the dye–fiber bonding fastness. This research methodology not only enhances the dyeing performance of MSPUF but also reduces energy consumption and dyeing costs, presenting an ecofriendly and economically novel approach for the development of dyeable MSPUF.