Recycled polyester fiber and flame-retardant polyester fiber both belong to the polyester fiber system and have the basic properties of polyester materials such as wear resistance, wrinkle resistance, and easy care. However, the classification dimensions, core functions, and application orientations of the two are significantly different. Recycled polyester fiber focuses on "environmental protection recycling", while flame-retardant polyester fiber focuses on "safety protection". Clarifying the difference between the two is the key to accurately matching environmental protection needs or safety demand scenarios. The following breaks down the differences between the two from four core dimensions.

The difference in definition and core attributes is the essential difference between the two. Regenerated polyester fiber is also called recycled polyester fiber. Its core attribute is "resource recycling". The raw materials are waste polyester products (such as mineral water bottles and old clothes) that are broken, cleaned, and melt-spun. Its core value is to reduce resource waste and environmental pollution. The core attribute of flame-retardant polyester fiber is "safety and flame retardancy." The fiber is given flame-retardant properties through a modification process. It can inhibit combustion and reduce smoke when exposed to fire. Its core value is to reduce fire risks and ensure the safety of people and property.

Differences in production processes determine functional focus. The key process of recycled polyester fiber is "recycling and regeneration", which requires waste raw material sorting, depolymerization, re-polymerization or direct melt spinning. The core difficulty is to control the purity of raw materials to ensure product stability; the key process of flame-retardant polyester fiber is "flame-retardant modification", which is divided into dope modification (flame retardant is added before spinning) and finishing modification (flame retardant is padded after the finished product). The core requirement is to ensure long-lasting flame retardant performance without affecting the basic mechanical properties of the fiber.

Performance and application scenarios show obvious differentiation. The performance of recycled polyester fiber is close to that of virgin polyester, and it is mainly used in scenes with high environmental requirements such as clothing (sportswear, sweatshirts), home textiles (bedding, curtains), and non-woven fabrics. Some high-end recycled polyester can be used in intimate clothing. The core performance of flame-retardant polyester fiber is a limiting oxygen index of ≥28% and short afterburning time. It is mainly used in fire-fighting clothing, industrial protective clothing, public building curtains, car interiors, children's products and other scenes that have mandatory requirements for safety and flame retardancy to avoid the rapid spread of fire in the event of a fire.

In summary, recycled polyester fiber takes "environmental protection and recycling" as its core positioning to serve the needs of green development; flame-retardant polyester fiber takes "safety and flame retardant" as its core positioning to ensure the safety of special scenes. Although both are polyester fibers, their functional orientations are completely different. They need to be accurately selected according to the environmental protection or safety requirements of the scene in order to fully utilize the core value of the material.