Fiberglass, a superior inorganic non-metallic material, boasts a wide variety of types with excellent insulation properties, high thermal resistance, good corrosion resistance, and high mechanical strength. However, it has the drawback of brittleness and poor wear resistance. It is produced from six types of ores, including phlogopite, quartz sand, limestone, dolomite, borosilicate, and magnesite, through high-temperature melting, fiber drawing, weaving, and other processes. The diameter of a single fiber ranges from several micrometers to twenty or more, equivalent to 1/20 to 1/5 of a human hair. Each bundle of fiber yarn is composed of hundreds, and even thousands, of single fibers. Fiberglass is commonly used as reinforcing material in composites, electrical insulation materials, thermal insulation materials, circuit boards, and various fields in the national economy.

The primary components include silicon dioxide, aluminum oxide, calcium oxide, boron oxide, magnesium oxide, sodium oxide, etc. Depending on the amount of alkali in the glass, it can be categorized into alkali-free glass fiber (sodium oxide 0%～2%, belonging to aluminum-borosilicate glass), medium-alkali glass fiber (sodium oxide 8%～12%, belonging to boron or non-boron sodium-calcium silicate glass), and high-alkali glass fiber (sodium oxide over 13%, belonging to sodium-calcium silicate glass).

Glass fiber, when used as a reinforcing material for plastics, boasts high tensile strength. The tensile strength is 6.3 to 6.9 g/d in standard conditions and 5.4 to 5.8 g/d in a wet state. It has excellent heat resistance, with no impact on strength at temperatures up to 300°C. It possesses superior electrical insulation properties, making it a high-grade electrical insulating material. It is also used in thermal insulation and fire shielding materials. Generally, it is only corroded by strong alkalis, hydrofluoric acid, and phosphoric acid.