Fiberglass Material Application Guide
There are many ways to classify fiberglass One method, based on the composition of the glass raw materials, is to classify fiberglass into alkali-free fiberglass (E glass), medium-alkali fiberglass (C glass), high-alkali fiberglass (A glass), alkali-resistant fiberglass (AR glass), and high-strength glass fibers (S glass). Currently, only alkali-free fiberglass are suitable for manufacturing fiberglass fishing boats. These include alkali-free fiberglass surface mats, alkali-free fiberglass woven fabrics, alkali-free fiberglass chopped strand mats, and alkali-free fiberglass multi-axial fabrics/composite fabrics. The following is a brief introduction to E, C, and A types of fiberglass.
I. Alkali-Free Fiberglass (E Glass)
Alkali-free fiberglass refers to aluminoborosilicate fiberglass with an alkali metal oxide (Na₂O and K₂O) content of less than 0.8%. It has excellent chemical stability, electrical insulation properties, and strength. Currently, over 90% of glass fibers used internationally are of E glass composition. According to the "Specifications for the Construction of Fiber-Reinforced Plastics for Fishing Boats," all fiberglass boats should use alkali-free fiberglass.
Currently, large-scale fiberglass manufacturers are actively researching and developing new types of alkali-free glass fibers to improve the fiber's strength, modulus, and chemical resistance, while simultaneously making glass fiber production more energy-efficient and environmentally friendly, and reducing production costs.
II. Medium-Alkali Glass Fiber (C Glass)
Medium-alkali glass refers to soda-lime silicate glass with an alkali metal oxide content ranging from 10% to 13%. Its characteristics include superior chemical resistance, especially acid resistance, compared to alkali-free glass, but poorer electrical properties and lower mechanical strength than alkali-free glass fiber.
Typically, imported medium-alkali fiberglass contain a certain amount of boron trioxide, while Chinese medium-alkali fiberglass are completely boron-free. Abroad, medium-alkali fiberglass is only used to produce corrosion-resistant fiberglass products, such as fiberglass surface mats, and also to reinforce asphalt roofing materials. However, in China, medium-alkali fiberglass still holds a certain market share, used for reinforcing fiberglass and in the production of filter fabrics and wrapping fabrics. For a long time, it was competitive due to its lower price compared to alkali-free fiberglass. However, with continuous technological breakthroughs and cost reductions in ultra-large-scale alkali-free furnaces, medium-alkali glass fiber no longer has a cost advantage.
In the future, the market share of products produced using outdated crucible drawing methods like medium-alkali fiberglass will gradually decrease and may even be eliminated.
III. High-alkali Glass Fiber (A Glass)
High-alkali fiberglass has a Na₂O and K₂O content of over 14.0%. It is generally drawn from raw materials such as crushed flat glass and crushed bottle glass and can be used as battery separators, pipe wrapping fabrics, and felt sheets. The forming temperature of high-alkali fiberglass is much lower than that of alkali-free and medium-alkali glass. Some small manufacturers use non-platinum spinnerets with high-alkali glass formulations to produce low-end products. High-alkali fiberglass is susceptible to water and atmospheric moisture erosion. In humid air, it quickly becomes brittle, loses strength, and becomes unusable. Currently, high-alkali fiberglass is rarely produced.
The country explicitly banned the production of high-alkali fiberglass as early as the 1980s, but a very small number of places still illegally produce it, even mixing it with alkali-free fiberglass to pass it off as high-quality. Therefore, all fiberglass fishing boat manufacturers must purchase products from reputable factories and never compromise safety by purchasing fiberglass fishing boats that pose a safety hazard!
