Due to the introduction of MgO, Cao and other components, it is conducive to expand the viscosity range of fiber forming, improve the fiber forming conditions, and improve the fiber forming rate and fiber softness. However, due to the introduction of MgO, Cao and other components, low melting point compounds such as Cao · SiO2 and Cao · MgO · 2SiO2 are generated, resulting in the reduction of fiber heat resistance.