What is the difference between alkali-free and medium-alkali glass fibers?

About alkali-free glass fibers and medium-alkali glass fibers
 Glass fiber is an inorganic non-metallic material with excellent performance. It uses natural ore as raw material and is mixed according to the designed formula. After high-temperature melting, drawing, winding, weaving, and other processes, various products are finally formed. It has the advantages of high strength, high elastic modulus, low elongation, good electrical insulation, and corrosion resistance. It is usually used as a reinforcing material, electrical insulation material, and thermal insulation material in composite materials, and is widely used in various fields of the national economy.
There are many ways to classify glass fibers. Generally, they can be classified in terms of glass raw material composition, monofilament diameter, fiber appearance, production method, and fiber characteristics. The classification of glass raw material composition is currently the most commonly used method, mainly used for the classification of continuous glass fibers. It is distinguished by different alkali gold oxide content. Alkali metal oxide generally refers to sodium oxide and potassium oxide, attracted by soda ash, thenardite, feldspar, and other substances. Alkali metal oxide is one of the main components of ordinary glass, and its main function is to lower the melting point of glass. However, the higher the content of alkali metal oxide in glass, the lower its chemical stability, electrical insulation performance, and strength will be. Therefore, glass fibers with different alkali content should be used for glass fibers for different purposes. Therefore, the alkali content of the glass fiber component is often used as a mark to distinguish continuous glass fibers for different uses. According to the alkali content in the glass composition, continuous fibers can be divided into the following types:

Non-alkali glass fiber: Alkali metal oxide (Na2O and K2O) content is less than 0.8%, is an aluminoborosilicate component. Its chemical stability, electrical insulation properties, and strength are very good.

Medium alkali glass fiber: alkali metal oxide (Na2O and K2O) content is 11.9%-16.4%, is a sodium calcium silicate component, because of its high alkali content, it can not be used as electrical insulation material, but its chemical stability And strength is better.

High alkali glass fiber: alkali metal oxide (Na2O and K2O) content is equal to or greater than 15%. Generally, it is made of broken flat glass and broken bottle glass as raw materials. At present, the country has banned the production of such products.