Polyamide (PA, commonly known as nylon) was the first resin developed for fiber by DuPont, which was industrialized in 1939.

Nylon is mainly used in synthetic fiber such as elastane or spandex elastane. Its most prominent advantage is that its wear resistance is higher than all other fibers, 10 times higher than cotton and 20 times higher than wool. When being stretched to 3-6%, the elastic recovery rate can reach 100%. It can bear thousands of twists and turns without breaking. The strength of nylon fiber is 1-2 times higher than cotton, 4-5 times higher than wool, and 3 times higher than viscose fiber.