Polyamide fiber is commonly known as Nylon. Its English name is Polyamide (referred to as PA). The density is 1.15 g/cm3, which is the molecular backbone chain, contains the repeated amide group [NHCO] -- the general term of thermoplastic resin, which including aliphatic PA, fatty - aromatic PA and aromatic PA. Among them, the aliphatic PA has many varieties, which has large production and wide application, and its name is determined by the number of carbon atoms of the synthetic monomer. It was invented by the famous American chemist Carlo Seth and his research team. Nylon is a statement of polyamide fiber, which can be made to long fiber or short fiber.