Its main ingredients are silicon oxide, alumina, calcium oxide, boron oxide, magnesium oxide, sodium oxide, etc. According to the amount of alkali content in the glass, it can be divided into alkaline -free glass fiber (0%to 2%sodium oxide, which is aluminum Borosilicate glass), alkali glass fiber (8%to 12%sodium oxide, sodium silicate glass with boron or boron -containing boron) and high -alkali glass fiber (more than 13%sodium oxide, which belongs to sodium and calcium Silicate glass).