The glass used to produce glass fiber is different from that of other glass products. The glass used for fibers that have been commercialized in the world consists of silica, alumina, 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% ~ 2%, belonging to aluminum borosilicate glass) and medium alkali glass fiber (sodium oxide 8% ~ 12%), It belongs to sodium calcium silicate glass containing or without boron) and high alkali glass fiber (more than 13% sodium oxide belongs to sodium calcium silicate glass).

1. E-glass, also known as alkali free glass, is a borosilicate glass. The most widely used glass component for glass fiber has good electrical insulation and mechanical properties. It is widely used in the production of glass fiber for electrical insulation and glass fiber for FRP. Its disadvantage is that it is easy to be eroded by inorganic acid, so it is not suitable for acid environment.

2. C-glass, also known as medium alkali glass, is characterized by better chemical resistance, especially acid resistance, than non alkali glass, but poor electrical performance and 10% ~ 20% lower mechanical strength than non alkali glass fiber. Generally, foreign medium alkali glass fiber contains a certain amount of boron trioxide, while China’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 also used to strengthen asphalt roofing materials. However, in China, medium alkali glass fiber accounts for more than half (60%) of the output of glass fiber and is widely used in the reinforcement of FRP and the production of filter fabric and binding fabric, 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, and its elastic modulus is 86000mpa, which is higher than that of E-glass fiber. The FRP products produced by them are mostly used in military industry, space, bulletproof armor and sports equipment. However, due to the high price, it can not be popularized in civil use, and the world output is about thousands of 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. It is rarely used to produce glass fiber because of its poor water resistance.

6. E-CR glass is an improved boron free and alkali free glass, which is used to produce glass fiber with good acid and water resistance. Its water resistance is 7 ~ 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 specially developed for underground pipelines and storage tanks.

7. D glass, also known as low dielectric glass, is used to produce low dielectric glass fibers with good dielectric strength.

In addition to the above glass fiber components, a new alkali free glass fiber has emerged in recent years. It does not contain boron at all, so as to reduce environmental pollution, but its electrical insulation and mechanical properties are similar to those of traditional E glass. In addition, there is a kind of glass fiber with double glass components, which has been used in the production of glass wool. It is said that it also has potential as FRP reinforcement. In addition, there is fluorine-free glass fiber, which is an improved alkali free glass fiber developed for environmental protection requirements.