Polyamide PA66 is a kind of engineering polymers (engineering plastics). These resins are mainly used in engineering applications where physical and mechanical properties are required. PA66 resin is a polymer synthesized by Wallace Hume Carothers in 1935. The process of manufacturing PA66 by spinning was discovered between 1936 and 1937 and commercialized by DuPont in the United States in late 1939.