Metallic phytates modified polyurethane coating for constructing long-lasting flame-retardant outdoor polyester fabric

The flame-retardant (FR) properties of polyurethane (PU)-coated polyester fabrics used in outdoor settings are unsatisfactory. This study aimed to enhance the FR performance of PU-coated polyester fabrics by synthesizing a series of metallic phytate salts through the chelation of phytic acid and four metal ions (Mg2+, Fe2+, Fe3+, Al3+). The flame retardancy, washing durability, mechanical properties, combustion performance, and FR mechanism of coated PET fabrics were investigated. Among the different metallic phytate salts, phytate aluminum salt exhibited stable FR efficiency without significantly affecting the mechanical performance of the fabric. The coated polyester fabric with 4 wt% phytate aluminum salt possessed a high LOI of 34.2 %, and achieved selfextinguishing action and met the requirements for B1 classification. The coated fabric also displayed remarkable flame retardancy and durability, even after undergoing 50 washing cycles. Moreover, the addition of phytate aluminum salt resulted in a significant reduction of 34.3 % and 56.8 % in total heat and smoke release, respectively, indicating high fire safety. The phytate aluminum salt acted as a catalyst for the dehydration and carbonization of the PU-coated polyester in the condensed phase. This research introduces a novel approach for producing sustainable and long-lasting FR PU-coated polyester fabrics.