Synthesis of Cationic Waterborne Polyurethane‐Polysiloxane Emulsion: Structure Regulation, Charge Compatibility Optimization, and Application in High‐Performance One‐Bath Softening–Dyeing Process

ABSTRACT Conventional textile dyeing and softening processes are plagued by high water consumption and wastewater with elevated chemical oxygen demand (COD). Achieving effective dye‐softener compatibility while maintaining multifunctional efficacy presents a formidable obstacle in one‐bath textile softening systems. Herein, a cationic waterborne polyurethane‐epoxy polyether silicone oil (WPU‐EPSI) emulsion is developed to reduce energy consumption and integrate multiple functionalities. Fabrics finished with the WPU‐EPSI formulation exhibit markedly enhanced performance, with the water droplet diffusion time reduced from 50 s to only 1.62 s. The contact angle of fabrics decreases from 125° to 67°, indicating excellent hydrophilicity. Furthermore, the finished fabrics exhibit a 98% whiteness retention rate, a higher Kubelka‐Munk (K/S) value, and an improved hand feel. This study establishes a promising paradigm for developing next‐generation textile auxiliaries and environmentally sustainable advancement in textile manufacturing.