Abstract: In the context of the rapid development of modern industry and increasing demand for public safety, flame-retardant functional yarns, as the core component of high-performance protective textiles, are facing technical bottlenecks in balancing durability of performance, thermal-moisture comfort, and mechanical properties. This paper reviews the classification of flame-retardant fiber materials and their fireretardant mechanisms, elaborates on yarn preparation technologies based on structural design, including intrinsic flame-retardant fiber spinning, inorganic/organic blending, intrinsic flame-retardant/organic blending, and intrinsic flame-retardant/inorganic blending, and analyzes the research progress in different application fields. In response to the key challenges in current research, such as difficulties in multifunctional integration, a lack of large-scale green preparation processes, and the absence of yarn-specific standard systems, future efforts should focus on developing multi-scale structural design, environmentally friendly and efficient preparation technologies, and specialized evaluation standards, to provide theoretical references for the upgrading of flame-retardant functional yarns.

Key words: flame-retardant functional yarns; flame-retardant mechanism; structural design; preparation processes