Insulating sheet materials, also known as dielectrics, are substances that do not conduct electricity or conduct electricity minimally under the application of direct voltage. The primary function of insulating sheet materials is to isolate conductors at different potentials within electrical equipment, allowing current to flow along a specific path. They also serve as mechanical support and fixation, as well as for arc quenching, heat dissipation, energy storage, moisture and mold prevention, and to improve the potential distribution of the electric field and protect conductors.