What is fiberglass?

There are many types of fiberglass. They can generally be classified according to the composition of the glass raw materials, monofilament diameter, fiber appearance, production method, and fiber characteristics.

 

1. Classification by Glass Raw Material Composition

 

This classification method is mainly used for continuous fiberglass. It is generally distinguished by the content of different alkali metal oxides, which typically refer to sodium oxide and potassium oxide. These are introduced into the glass raw materials by substances such as soda ash, mirabilite, and feldspar. Alkali metal oxides are one of the main components of ordinary glass, and their main function is to lower the melting point of the glass. However, the higher the content of alkali metal oxides in the glass, the lower its chemical stability, electrical insulation properties, and strength will be. Therefore, different alkali contents are used in the production of fiberglass for different applications. Thus, the alkali content of fiberglass is often used as a marker to distinguish fiberglass for different applications. Based on the alkali content in the glass composition, continuous fibers can be divided into the following types:

 

1.1 Alkali-free fiber (commonly known as E-glass)
It has an R2O content of less than 0.8% and is an aluminoborosilicate component. It has excellent chemical stability, electrical insulation properties, and strength. Mainly used as electrical insulation materials, reinforcing materials for fiberglass, and tire cord. Medium-alkali fiber: With an R2O content of 11.9%-16.4%, it is a sodium-calcium silicate component. Due to its high alkali content, it cannot be used as an electrical insulation material, but its chemical stability and strength are relatively good. It is generally used as the base material for latex cloth, woven fabric, acidic filter cloth, and window screen, and can also be used as a reinforcing material for fiberglass where electrical performance and strength requirements are not very strict. This type of fiber has a lower cost and wider applications.

 

1.2 High-alkali fiber: Glass components with an R2O content equal to or greater than 15%. Fiberglass drawn from raw materials such as crushed flat glass and crushed bottle glass belong to this category. They can be used as waterproof and moisture-proof materials such as battery separators, pipe wrapping cloth, and felt sheets. Special fiberglass: such as high-strength glass fibers composed of pure magnesium-aluminum-silicon ternary elements; magnesium-aluminum-silicon series high-strength and high-elasticity glass fibers; silicon-aluminum-calcium-magnesium series chemically resistant glass fibers; aluminum-containing fibers; high-silica fibers; quartz fibers, etc.

 

2. Classification by Monofilament Diameter

 

Fiberglass monofilaments are cylindrical, so their thickness can be expressed by their diameter. Generally, drawn fiberglass are classified into several types based on their diameter range (diameter values ​​are in µm):

 

2.1 Coarse Fiber: Monofilament diameter is generally 30 µm.

2.2 Primary Fiber: Monofilament diameter is greater than 20 µm.

2.3 Intermediate Fiber: Monofilament diameter is 10-20 µm.

2.4 High-Grade Fiber (Also known as Textile Fiber): Monofilament diameter is 3-10 µm.

 

Fiberglass with a monofilament diameter less than 4 µm are also called microfibers.

 

Different monofilament diameters not only affect fiber properties but also influence fiber production processes, yield, and cost. Generally, 5-10 µm fibers are used for textile products, while 10-14 µm fibers are more suitable for untwisted rovings, nonwoven fabrics, and chopped strand mats.

 

3. Classification by Fiber Appearance

 

The appearance of glass fibers, i.e., their shape and length, depends on their production method and their application. For example, continuous fibers (also known as textile fibers) are theoretically infinitely continuous fibers, mainly produced using the spinneret method. After textile processing, they can be made into glass yarn, ropes, cloth, belts, untwisted roving, and other products.

 

3.1 Fixed-Length Fibers These have a limited length, generally 300-500mm, but can sometimes be longer, such as the mostly disordered long fibers found in felts. For example, long cotton produced using the steam blowing method, when broken into yarn, is only a few hundred millimeters long.

Other products include rod-processed yarn and single-stage roving, all used to make yarn or felts.

 

3.2 Glass Wool This is also a type of fixed-length fiberglass, but its fibers are shorter, generally less than 150mm or even shorter. Morphologically, it has a loose, cotton-like structure, hence the name short cotton. It is mainly used for insulation and sound absorption. In addition, there are chopped fibers, hollow fibers, glass fiber powder, and finely ground fibers.

 

4. Classification by Fiber Properties

This is a new type of glass fiber developed to meet specific application requirements and possessing certain unique and superior properties. It can be broadly classified into: high-strength glass fiber, high-modulus glass fiber, high-temperature resistant fiberglass, alkali-resistant fiberglass, acid-resistant fiberglass, ordinary glass fiber (referring to alkali-free and medium-alkali glass fiber), optical fiber, low-dielectric-constant fiberglass, conductive fiber, etc.

 

Fiberglass is a high-performance inorganic non-metallic material. Its original English name is glassfiber or fiberglass. Its components include silicon dioxide, aluminum oxide, calcium oxide, boron oxide, magnesium oxide, sodium oxide, etc. It is produced from glass spheres or waste glass through high-temperature melting, drawing, winding, and weaving processes. Finally, various products are formed. The diameter of glass fiber monofilaments ranges from a few micrometers to more than twenty micrometers, which is equivalent to 1/20 to 1/5 of a human hair. Each bundle of fiber filaments consists of hundreds or even thousands of monofilaments. They are commonly used as reinforcing materials in composite materials, electrical insulation materials, thermal insulation materials, circuit boards, etc., and are widely used in various fields of the national economy.