The glass used in the production of glass fiber is different from the glass used in other glass products. The glass components of commercialized fibers internationally are silicon dioxide, aluminum oxide, calcium oxide, boron oxide, magnesium oxide, sodium oxide, etc. According to the alkali content in the glass, it can be divided into alkali-free glass fiber (sodium oxide 0% to 2%, aluminoborosilicate glass), medium-alkali glass fiber (sodium oxide 8% to 12%, soda-lime silicate glass with or without boron) and high-alkali glass fiber (sodium oxide 13% or more, soda-lime silicate glass) .
1. E-glass, also known as alkali-free glass, is a borosilicate glass. It is the most widely used glass component for glass fiber. It has good electrical insulation and mechanical properties. It is widely used in the production of glass fiber for electrical insulation and is also widely used in the production of glass fiber for FRP. Its disadvantage is that it is easily corroded by inorganic acids, so it is not suitable for use in acidic environments.
2. C-glass is also called medium-alkali glass. Its characteristics are that its chemical resistance, especially acid resistance, is better than that of alkali-free glass, but its electrical properties are poor and its mechanical strength is 10% to 20% lower than that of alkali-free glass fiber. Usually, foreign medium-alkali glass fiber contains a certain amount of boron trioxide, while my country's medium-alkali glass fiber does not contain boron at all. In foreign countries, medium-alkali glass fiber is only used to produce corrosion-resistant glass fiber products, such as glass fiber surface felt, and is also used to reinforce asphalt roofing materials. However, in my country, medium-alkali glass fiber accounts for more than half (60%) of glass fiber production and is widely used in the reinforcement of FRP and the production of filter fabrics, wrapping fabrics, etc. Because its price is lower than that of alkali-free glass fiber, it has strong competitiveness.
3. High-strength glass fiber is characterized by high strength and high modulus. Its single fiber tensile strength is 2800MPa, which is about 25% higher than that of alkali-free glass fiber. Its elastic modulus is 86000MPa, which is higher than that of E-glass fiber. FRP products made from them are mostly used in military, space, bulletproof armor and sports equipment. However, due to their high price, they have not been widely used in civilian applications, and the global production is only a few thousand tons.
4. AR glass fiber, also known as alkali-resistant glass fiber, is mainly developed to strengthen cement.
5. A glass, also known as high-alkali glass, is a typical sodium silicate glass. Due to its poor water resistance, it is rarely used in the production of glass fiber.
6. E-CR glass is an improved boron-free alkali-free glass used to produce glass fiber with good acid and water resistance. Its water resistance is 7 to 8 times better than that of alkali-free glass fiber, and its acid resistance is much better than that of medium-alkali glass fiber. It is a new variety developed specifically for underground pipelines, storage tanks, etc.
7. D glass, also known as low-dielectric glass, is used to produce low-dielectric glass fiber with good dielectric strength.
In addition to the above glass fiber components, a new alkali-free glass fiber has emerged in recent years. It is completely free of boron, thereby reducing environmental pollution, but its electrical insulation and mechanical properties are similar to those of traditional E glass. There is also a kind of glass fiber with double glass components, which has been used in the production of glass wool and is said to have potential as a fiberglass reinforced material. In addition, there is fluorine-free glass fiber, which is an improved alkali-free glass fiber developed for environmental protection requirements.