Glass fiber can be divided into continuous fiber, fixed length fiber and glass wool according to its shape and length. According to the composition of glass, it can be divided into alkali-free, chemical-resistant, high alkali, medium alkali, high strength, high elastic modulus and alkali-resistant (alkali-resistant) glass fibers.
The main raw materials for producing glass fiber are quartz sand, alumina and pyrophyllite, limestone, dolomite, boric acid, soda ash, mirabilite and fluorite. Production methods can be roughly divided into two categories: one is to directly make molten glass into fibers; One is that molten glass is made into glass balls or rods with a diameter of 20mm, and then heated and remelted in various ways to make very fine fibers with a diameter of 3 ~ 80 μ m. Infinite-length fiber made by mechanical drawing square method through platinum alloy plate is called continuous glass fiber, commonly known as long fiber. Discontinuous fibers made by roller or air flow are called fixed-length glass fibers, commonly known as short fibers.
Glass fiber is divided into different grades according to its composition, properties and uses. According to the standard grade (see table), E-grade glass fiber is the most widely used and widely used in electrical insulation materials. Class s is a special fiber.
The glass used for grinding glass fiber to produce glass fiber is different from other glass products. The glass components for fibers that have been commercialized internationally are as follows:
E- glass
Also known as alkali-free glass, it is a borosilicate glass. At present, it is the most widely used glass fiber, which has good electrical insulation and mechanical properties. It is widely used in the production of glass fiber for electrical insulation and glass fiber for glass fiber reinforced plastic. Its disadvantage is that it is easy to be corroded by inorganic acids, so it is not suitable for acid environment.
C- glass
Glass fiber rod, also known as medium-alkali glass, is characterized by better chemical resistance, especially acid resistance, than alkali-free glass, but its electrical performance is poor, and its mechanical strength is 10% ~ 20% lower than that of alkali-free glass fiber. Usually, 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 glass fiber production, and is widely used in the reinforcement of glass fiber reinforced plastic and the production of filter fabrics and wrapping fabrics, because its price is lower than that of alkali-free glass fiber and it has strong competitiveness.
high strength glass fiber
It 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 with 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 now, and the world output is about several thousand tons.
AR glass fiber
Also known as alkali-resistant glass fiber, alkali-resistant glass fiber is the rib material of glass fiber reinforced (cement) concrete (GRC for short), which is 100% inorganic fiber and an ideal substitute for steel and asbestos in non-load-bearing cement components. Alkali-resistant glass fiber is characterized by good alkali resistance, effective resistance to the corrosion of high-alkali substances in cement, strong grip, extremely high elastic modulus, impact resistance, tensile strength and bending strength, strong incombustibility, frost resistance, temperature and humidity change resistance, excellent crack resistance and impermeability, strong designability and easy molding. Alkali-resistant glass fiber is a new type widely used in high-performance reinforced (cement) concrete.
A glass
Also known as high alkali glass, is a typical sodium silicate glass, which is rarely used to produce glass fiber because of its poor water resistance.
E-CR glass
It is an improved boron-free and alkali-free glass, which is used to produce glass fiber with good acid resistance 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.
D glass
Also known as low dielectric glass, it 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, which contains no boron at all, thus reducing 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, and is said to have potential as a FRP reinforcement. In addition, there is fluorine-free glass fiber, which is an improved alkali-free glass fiber developed for environmental protection requirements.
Identifying high alkali glass fiber
The simple method of inspection is to boil the fiber in boiling water for 6-7 hours. If it is high alkali glauber’s salt fiber, after boiling water, the fiber in the warp and weft directions will be
All the dimensions are loose.
According to different standards, there are many ways to classify glass fibers, generally from the perspectives of length and diameter, composition and performance.
Post time: Feb-16-2023