Fiberglass classification, raw material formulation determines performance, and tow specifications affect applications.
Fiberglass is one of the most widely used reinforcing fibers in the field of composite materials. Its classification can be based on three core dimensions: raw material composition, performance characteristics, and tow specifications. Different categories correspond to different application directions. The following is a detailed classification and application adaptation logic.
I. Classification by Raw Material Composition
The raw materials for fiberglass are mainly quartz sand, soda ash, and limestone. By adjusting the formula, glass systems with different chemical compositions can be formed. Common categories are as follows:
1. Alkali-free fiberglass (E-fiberglass): The alkali metal oxide content is <2%, and the main components are SiO2, Al2O3, CaO, and B2O3. It contains no obvious alkali metal components. It has excellent insulation properties, balanced mechanical strength, good corrosion resistance (except for strong acids and alkalis), and high cost-effectiveness. It is mainly used as the core reinforcement in general-purpose composite materials, such as wind turbine blades, electronic and electrical insulation boards, automotive body parts, pipelines, and storage tanks.
2. Medium-alkali fiberglass (C-fiberglass) has an alkali metal oxide content of 8%~12% and a low B2O3 content, resulting in lower cost than alkali-free fiberglass. Its chemical corrosion resistance (especially acid resistance) is superior to alkali-free fiberglass, but its insulation and mechanical strength are slightly lower. It is mainly suitable for corrosion protection applications with low insulation requirements, such as chemical corrosion-resistant pipe linings, asphalt waterproofing material reinforcement, and ordinary fiberglass products.
3. High-alkali fiberglass has an alkali metal oxide content >12%, mostly made from recycled glass, resulting in 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 low-end products like thermal insulation cotton, sound insulation felt, and filter materials.
4. High-strength fiberglass (S-fiberglass/HS-fiberglass) has an extremely low alkali metal content. Its tensile strength and elastic modulus are much higher than E-fiberglass, and it has good high-temperature resistance. It is mainly used in high-performance composite materials, such as aerospace secondary structural components, high-end sports equipment (golf clubs, sailboat masts), and military protective equipment.
5. High-modulus fiberglass (M-fiberglass) contains MgO and other components, with an elastic modulus of 95-110 GPa. It has strong resistance to deformation, but its strength is slightly lower than that of S-fiberglass. It is mainly used in the production of structural components requiring high rigidity, such as satellite brackets, precision instrument housings, and high-end automotive drive shafts.
6. Alkali-resistant fiberglass (AR-fiberglass) incorporates alkali-resistant components such as ZrO2, with controllable alkali metal content. It maintains stable mechanical properties in alkaline environments such as cement and gypsum, and has outstanding resistance to alkali corrosion. It is mainly used in the production of fiber-reinforced cement (GRC) components, concrete crack-resistant reinforcement, and wall insulation mesh in the construction field.
II. Classification by Performance Characteristics This classification supplements the raw material classification, focusing on the "functional properties" of fiberglass.
1. Temperature-resistant fiberglass has a softening point >900℃, and some varieties can withstand short-term temperatures above 1000℃. It has good thermal stability and is mainly used in aero-engine heat shields, industrial kiln insulation layers, and fire-retardant composite materials.
2. Insulating fiberglass has a volume resistivity > 10¹⁴ Ω·cm, low dielectric loss, and good arc resistance. It is mainly used in the production of printed circuit board (PCB) substrates, high-voltage electrical insulation bushings, radar radomes, etc.
3. Corrosion-resistant fiberglass is resistant to acids, alkalis, and organic solvents, exhibiting minimal performance degradation under harsh chemical environments. It is mainly used in chemical storage tanks, marine corrosion-resistant components, and wastewater treatment equipment.
III. Classification by Tow Size Tow size refers to the number of monofilaments in a single fiber bundle, directly affecting the molding efficiency and product performance of composite materials.
1. Fine yarn (small tow): The number of monofilaments per bundle is < 2000, with a low tex value. It has good wettability and high molding precision, and can be woven into fine fabrics. It is mainly used in the production of high-precision aerospace components, electronic-grade copper-clad laminates, high-end sports equipment, and precision instrument parts.
2. Medium yarn: The number of monofilaments per bundle is 2000~4800. It balances molding efficiency and product uniformity, offering high cost-effectiveness. 3. **Ribbon (Large Tow):** Primarily used in the production of medium-sized structural components such as wind turbine blade skins, automotive body parts, and ship decks.
4. **Roving (Large Tow):** With over 4800 filaments per bundle and a high tex value, roving offers high production efficiency and low unit cost, making it suitable for mass production processes. It is mainly used in the production of large structural components such as pultruded profiles (e.g., FRP pipes, profile supports), spray-molded products (e.g., storage tanks, ship hulls), and wound products (e.g., high-pressure gas cylinders).
5. **Chopted Ribbon:** Continuous fiberglass is cut into short fibers of 3-50 mm. It can be divided into chopped yarn (for composite materials) and ground fiber (for fillers). It is easily dispersed and can be mixed with resins, plastics, and other matrices for molding. It is mainly used in the production of fiberglass reinforced plastic (FRP) injection molded parts, BMC/DMC molding compounds, and building mortar reinforcement. In summary, fiberglasss can be clearly categorized based on three core dimensions: raw material composition, performance characteristics, and tow specifications. This clear classification system not only helps downstream companies accurately match suitable materials for different scenarios such as wind power, aviation, construction, and electronics, but also provides direction for upstream companies in formula optimization, functional modification, and other technological research and development. As application areas continue to expand, the classification of fiberglasss will become more refined in the future, further promoting the industry's adaptation to diverse and customized needs across various fields and helping the composite materials industry achieve the optimal balance between performance and cost.
