Understanding the classification of glass fiber in one article: raw material formula determines performance, and fiber bundle specifications affect application

Glass fiber is one of the most widely used reinforcing fibers in the field of composite materials. Its classification can be divided into three core dimensions: raw material composition, performance characteristics, and bundle specifications. Different categories correspond to differentiated application directions. The following is a detailed classification and application adaptation logic.

1、 Classified by raw material composition
The raw materials for glass fiber are mainly quartz sand, soda ash, limestone, etc. By adjusting the formula, glass systems with different chemical compositions can be formed. The common categories are as follows:
1. The alkali metal oxide content of alkali free glass fiber (E-glass fiber) is less than 2%, mainly composed of SiO2, Al2O3, CaO, B2O3, without obvious alkali metal components. It has excellent insulation, balanced mechanical strength, good corrosion resistance (except for strong acids and alkalis), and high cost-effectiveness. It is mainly used as the core reinforcement of general composite materials, such as wind turbine blades, electronic and electrical insulation boards, automotive body components, pipeline storage tanks, etc.
2. The alkali metal oxide content of medium alkali glass fiber (C-glass fiber) is 8%~12%, with lower B2O3 content and lower cost than alkali free glass fiber. Its chemical corrosion resistance (especially acid resistance) is better than alkali free glass fiber, but its insulation and mechanical strength are slightly lower. It is mainly suitable for anti-corrosion scenarios with low insulation requirements, such as chemical anti-corrosion pipeline lining, asphalt waterproof material reinforcement, ordinary fiberglass products, etc.
3. The alkali metal oxide content of high alkali glass fiber is greater than 12%, mostly made from recycled glass as raw material, with extremely low cost. Its mechanical properties and weather resistance are poor, and its insulation is weak. It is mainly used in non structural reinforcement fields, such as insulation cotton, soundproof felt, filter materials and other low-end products.
4. High strength glass fiber (S-glass fiber/HS glass fiber) has extremely low alkali metal content, and its tensile strength and elastic modulus are much higher than E-glass fiber. It has good high temperature resistance and is mainly used in high-performance composite materials, such as aerospace secondary structural components, high-end sports equipment (golf clubs, sailing masts), military protective equipment, etc.
5. High modulus glass fiber (M-glass fiber) contains MgO and other components, with an elastic modulus of 95-110 GPa and strong deformation resistance, but slightly lower strength than S-glass fiber. It is mainly used for producing structural components with high stiffness requirements, such as satellite brackets, precision instrument casings, high-end automotive drive shafts, etc.
6. Alkali resistant glass fiber (AR glass fiber) introduces alkali resistant components such as ZrO2, with controllable alkali metal content. It can maintain stable mechanical properties in alkaline environments such as cement and gypsum, and has outstanding alkali corrosion resistance. It is mainly used in the production of fiber-reinforced cement (GRC) components, concrete crack resistance enhancement, wall insulation mesh cloth, etc. in the field of construction.
2、 Classified by performance characteristics
This classification is a supplement to the classification of raw materials, focusing on the "functional properties" of glass fibers.
1. The softening point of heat-resistant glass fiber is greater than 900 ℃, and some categories can withstand short-term high temperatures above 1000 ℃. It has good thermal stability and is mainly used in the fields of aircraft engine insulation covers, industrial kiln insulation layers, fire-resistant and flame-retardant composite materials, etc.
2. The volume resistivity of insulating glass fiber is greater than 1014 Ω· cm, with low dielectric loss and good arc resistance. Mainly used for producing printed circuit board (PCB) substrates, high-voltage electrical insulation sleeves, radar antenna covers, etc.
3. Corrosion resistant glass fiber is acid/alkali/organic solvent resistant, with minimal performance degradation in harsh chemical environments. It is mainly used in chemical storage tanks, marine anti-corrosion components, sewage treatment equipment, etc.
3、 Classified by fiber bundle specifications
The specification of the fiber bundle refers to the number of single fibers in a single bundle, which directly affects the molding efficiency and product performance of composite materials.
1. Fine yarn (small bundle) has a single filament count of less than 2000, a low tex value, good wettability, high forming accuracy, and can be woven into fine fabrics. It is mainly used in the production of high-precision components for aerospace, electronic grade copper-clad laminates, high-end sports equipment, precision instrument components, etc.
2. The number of single strands of medium yarn is 2000-4800, which balances molding efficiency and product uniformity, and has a high cost-effectiveness. Mainly used for producing medium-sized structural components such as wind turbine blade skins, automotive body parts, and ship decks.
3. The single strand count of coarse yarn (large fiber bundle) is greater than 4800, with a high tex value, high production efficiency, low unit cost, and suitable for large-scale forming processes. It is mainly used for the production of extruded profiles (such as fiberglass pipes and profile supports), spray formed products (such as storage tanks and ship hulls), winding products (such as high-pressure gas cylinders) and other large structural components.
4. Short cut raw fibers are continuous glass fibers cut into 3-50mm short fibers, which can be divided into short cut yarns (used for composite materials) and ground fibers (used for filling). They are easy to disperse and can be mixed with resin, plastic and other matrices to form. They are mainly used in the production of glass fiber reinforced plastic (FRP) injection molded parts, BMC/DMC molding materials, building mortar reinforcement, etc.
In summary, glass fiber can be clearly classified into categories based on three core dimensions: raw material composition, performance characteristics, and fiber bundle specifications. A clear classification system can not only help downstream enterprises accurately match and adapt materials for different scenarios such as wind power, aviation, construction, and electronics, but also provide direction for upstream enterprises' formulation optimization, functional modification, and other technological research and development. With the continuous expansion of application fields, the classification of glass fibers will become more refined in the future, further promoting the industry to adapt to the diverse customized needs of various fields, and helping the composite materials industry achieve the optimal balance between performance and cost.