Resin based reactive compounds used for electrical insulation. Specifications for individual materials. Filled polyurethane compounds. Sheet 4: Filled polyurethane compounds|Composite materials, Electrical equipment, Fillers, Polymers, Thermal properties of materials, Electrical insulation, Solid electrical insulating materials, Resins (natural), Liquid electrical insulating materials, Properties, Polyurethane, Classification systems, Specification (approval), Electrical insulating materials, Plastics