Specialty fibers are chemical fibers with special physical and chemical structures, properties and uses, or special functions. Most of these fibers are used in various aspects of industry, national defense, medical treatment, environmental protection and cutting-edge science. Special fibers have different special properties, such as strong corrosion resistance, low wear, high temperature resistance, radiation resistance, flame resistance, high voltage resistance, high strength and high modulus, high elasticity, reverse osmosis, high-efficiency filtration, adsorption, ion exchange, Light guide, conduction and various medical functions.

According to performance, special fibers can be divided into corrosion-resistant fibers, high-temperature-resistant fibers, flame-resistant fibers, high-strength and high-modulus fibers, functional fibers, and elastomeric fibers.

① Corrosion-resistant fiber: that is, fluorine-containing fiber. There are polytetrafluoroethylene fiber (Teflon TFE), tetrafluoroethylene-hexafluoropropylene copolymer fiber (TeflonFEP), polyvinylidene chloride fiber (Kynar), ethylene-trifluorochloroethylene copolymer fiber (Halar), etc.

② High temperature resistant fibers: polym-phenylene isophthalamide fiber (No-mex), polyimide fiber (Αримид ∏Μ), polyphenylsulfone amide fiber (СульФон-Τ), polyamideimide fiber (Kermel), polybenzimidazole fiber (PBI), etc.

③ Flame-resistant fibers: phenolic fibers (Kynol), aromatic polyamide surface chemically treated fibers, metal chelating fibers, polyacrylonitrile pre-oxidized fibers (Pyromex), etc.

④ High-strength and high-modulus fibers: polyphthalamide p-phenylene diamine fiber (Kevlar), aramid copolymer fiber (HM-50), heterocyclic polyamide fiber (Βниивлон СBM), carbon fiber (Torayca) , graphite fiber (M40), silicon carbide fiber, etc.

⑤ Functional fibers: hollow fiber semi-permeable membranes (B-9, B-10, PRISM, etc.), activated carbon fibers (KF, etc.), microfiber felts (Ф∏∏15, etc.), oil-absorbing fiber felts (Tafnel, etc.), Optical fiber (Crofon, Eska, etc.), conductive fiber (Antron III), etc.

⑥ Elastomer fibers: polyester and polyether polyurethane fibers (Spandex), polyacrylate fibers (Anidex), polybutylene terephthalate fibers (Fibre-L), etc.

Most specialty fibers are produced by wet spinning. The preparation process of some special fibers is more difficult, such as spinning fibers with low molecular weight or linear shape by traditional spinning technology, and then performing cyclization, crosslinking, metal chelation, high temperature heat treatment, surface physical and chemical treatment or plasma Finished fibers can be obtained through processing and other processes; others need to use emulsion spinning, reaction spinning, liquid crystal spinning, dry spray wet spinning, phase separation spinning, high-voltage electrospinning, high-speed airflow melt jetting and special compounding Spinning technology and other new spinning processes; some use existing synthetic fibers to obtain various ion exchange groups or convert them into special fibers through functional group reactions.