色综合久久无码五十路人妻,婷婷射精av这里只有精品,欧美成人精品高清在线蜜芽,国产精品综合日韩精品已满

"Nylon", also known as "Capron" and "Chinlon", its chemical name is polyamide fiber. Everyone is no stranger to nylon, because the nylon products can be found everywhere in daily life. However, few people know its history. Nylon is the first synthetic fiber developed in the world.