With economic development and scientific advancement, the glass industry has also continued to advance, developing new varieties while also strengthening existing glass types. Various types of deeply processed glass have gradually replaced ordinary flat glass and are flourishing in their respective applications.
Types of Glass Fiber
Glass fiber can be categorized by form and length as continuous fiber, fixed-length fiber, and glass wool. Based on glass composition, it can be classified as alkali-free, chemical-resistant, high-alkali, medium-alkali, high-strength, high-elastic modulus, and alkali-resistant (alkali-resistant) glass fiber.
The main raw materials for producing glass fiber are quartz sand, alumina, pyrophyllite, limestone, dolomite, boric acid, soda ash, sodium sulfate, and fluorite.
Production methods can be broadly divided into two categories:
One is to directly convert molten glass into fibers.
The other is to first convert molten glass into glass balls or rods with a diameter of 20 mm, then heat and remelt them in various ways to produce very fine fibers with diameters of 3 to 80 μm. Fibers of infinite length drawn mechanically from platinum alloy sheets are called continuous glass fibers, commonly known as long fibers. Discontinuous fibers produced by rollers or airflow are called fixed-length glass fibers, commonly known as short fibers.
Glass fibers are classified into different grades based on their composition, properties, and applications. According to standard grade specifications (see table), E-grade glass fibers are more commonly used and are widely used in electrical insulation materials; S-grade glass fibers are specialized fibers.
Functions of Glass Fiber
1. Enhances rigidity and hardness. Adding glass fibers can increase the strength and rigidity of plastics, but the toughness of the same plastic will decrease. Example: flexural modulus;
2. Improve heat resistance and heat deformation temperature; For example, adding glass fiber to nylon increases the heat deformation temperature by at least two times. Typical glass-reinforced nylon can withstand temperatures exceeding 220°C;
3. Improve dimensional stability and reduce shrinkage;
4. Reduce warping;
5. Reduce creep;
6. Impact on flame retardancy due to the wicking effect, which can interfere with the flame retardant system and affect flame retardancy;
7. Reduce surface gloss;
8. Increase hygroscopicity;
9. Glass fiber treatment: The length of the glass fiber directly affects the brittleness of the material. Improper glass fiber treatment will reduce impact strength, while long fibers will improve impact strength. To minimize a significant decrease in material brittleness, glass fibers of a certain length must be selected.
