Acrylic fiber: Acrylic fiber refers to acrylic fiber, which is a kind of chemical fiber and developed by DuPont. Its appearance is round or splayed, its surface is smooth, and it is not easy to absorb water, acid, alkali and sunlight, and it is not easy to yellow and dye. However, the thermal insulation is not as good as wool, and the surface of the finished product is easy to pilling. Commonly known as polyacrylonitrile fiber.