Glass fiber According to the shape and length, can be divided into continuous fiber, fixed-length fiber and glass wool, according to glass composition, can be divided into alkali-free, chemical resistance, high alkali, medium alkali, high-strength, high modulus of elasticity and alkali (alkali-resistant) glass fiber. The main raw materials for the production of glass fiber are quartz sand, alumina and pyrophyllite, limestone, dolomite, boric acid, soda ash, Glauber's salt, fluorite and so on. The production method is broadly divided into two categories: one is to make the fused glass directly into the fiber, one is to make the fused glass first 20mm diameter glass ball or rod, and then in many ways to heat remelting after the diameter of the 3 of very fine fibers. An infinitely long fiber, called a continuous glass fiber, commonly known as a long fiber, is drawn by a mechanical drawing method through a platinum alloy plate. A discontinuous fiber made of a roller or air stream, known as a fixed-length glass fiber, commonly referred to as short fiber. Glass fiber is divided into different levels according to its composition, nature and use. In accordance with the standard level (see table), E-grade glass fiber is most commonly used, widely used in electrical insulating materials.