Glass fibers are generally classified according to glass raw material composition, filament diameter, fiber properties, fiber appearance, etc. Glass fibers include twisted roving, direct roving, chopped strands, roving cloth, glass fiber mat, friction material, continuous glass fiber, etc.

1. Classification of glass raw material components:

Generally, they are distinguished by the different alkali metal oxide contents.
(1) Alkali-free fiber (commonly known as E glass): R2O content is less than 0.8%, and it is an aluminum borosilicate component. It has good chemical stability, electrical insulation performance and strength. It is mainly used as electrical insulation material, FRP reinforcement material and tire cord.
(2) Medium alkali fiber: R2O content is 11.9%-16.4%, and it is a sodium calcium silicate component. Due to its high alkali content, it cannot be used as an electrical insulation material, but its chemical stability and strength are good. It is generally used as latex cloth, gingham cloth substrate, acid filter cloth, window screen substrate, etc.
(2) High alkali fiber: Glass component with R2O content equal to or greater than 15%. For example, glass fiber drawn from broken flat glass, broken bottle glass, etc. It can be used as waterproof and moisture-proof materials such as battery spacers, pipe wrapping cloth and felt.

2. Classification by monofilament diameter:

Glass fiber monofilaments are cylindrical, and the thickness can be expressed by diameter.

(1) Coarse fiber: its monofilament diameter is generally 30um

(2) Primary fiber: its monofilament diameter is greater than 20um;

(3) Intermediate fiber: its monofilament diameter is 10-20um

(4) Advanced fiber: (also called textile fiber) its monofilament diameter is 3-10um.

3. Classification by fiber characteristics:

Fibers: high-strength glass fiber; high-modulus glass fiber; high-temperature resistant glass fiber; alkali-resistant glass fiber; acid-resistant glass fiber; ordinary glass fiber (referring to alkali-free and medium-alkali glass fiber); optical fiber; low dielectric constant glass fiber; conductive fiber, etc.

Additional information:
Glass fiber (originally called glass fiber or fiberglass in English) is an inorganic non-metallic material with excellent performance. There are many types of glass fiber. Its advantages are good insulation, strong heat resistance, good corrosion resistance, and high mechanical strength, but its disadvantages are brittleness and poor wear resistance. It is made of seven kinds of minerals, including pyrophyllite, quartz sand, limestone, dolomite, colemanite, and magnesia stone, through high-temperature melting, wire drawing, winding, weaving and other processes. The diameter of its single filament is several microns to more than 20 microns, which is equivalent to 1/20-1/5 of a hair. Each bundle of fiber strands is composed of hundreds or even thousands of single filaments.