evvf3.cn-久久久一区二区,国产精品午夜春色av,色狠狠桃花综合,伦理电影国产精品

"The scientific name of nylon is polyamide, which is also a general term for thermoplastic resins. There are many kinds of nylon, with large production capacity and wide application. And its molecular structure is nylon fiber.

Nylon has good comprehensive properties, and its fiber strength is 1-2 times higher than that of cotton. It has the significant advantage of replacing steel, iron, copper and other metals with plastics in production and manufacturing, and is an important engineering plastic.