Glass fiber, abbreviated as "glass fiber", is a new material and metal substitute material that plays a reinforcing role. The diameter of its monofilament ranges from a few microns to over twenty microns, which is equivalent to 1/20-1/5 of a hair strand. Each bundle of fiber strands is composed of hundreds or even thousands of monofilaments.

Glass fiber is commonly used as a reinforcing material in composite materials, electrical insulation materials, thermal insulation materials, circuit substrates, and other fields of the national economy.

When glass fiber is used as a reinforcing material for reinforced plastics, its main characteristic is high tensile strength. The tensile strength is 6.3~6.9 g/d in the Standard state and 5.4~5.8 g/d in the wet state. Density 2.54g/cm3. Good heat resistance, with no effect on strength when the temperature reaches 300 ℃. It has excellent electrical insulation properties and is a superior electrical insulation material. It is also used as insulation material and fireproof shielding material. Generally, it is only corroded by concentrated alkali, hydrofluoric acid, and concentrated phosphoric acid.