Solid insulating materials can be divided into inorganic and organic two categories.

Inorganic solid epoxy glass laminate sheet are mainly powder mica and mica products, glass, glass fiber and its products, as well as porcelain, alumina film. They are resistant to high temperatures, are not aging, have considerable mechanical strength, some of which are materials such as low cost, occupying a certain position in the application. The disadvantage of inorganic solid electrical insulating board is poor processing performance, difficult to adapt to the electrical equipment on the molding requirements of insulating materials.
Mica and powder mica products with long-term anti-corona characteristics, high-voltage equipment is an important part of the insulation structure can also be used for high temperature occasions.
The glass process is simpler than the ceramic and can be used to make it. Glass fiber can be made of silk, cloth, belt, with much higher than the organic fiber heat resistance, in the insulation structure to the development of high temperature plays an important role.