Development of Polyester Film Organic Solid Insulation Materials
In the 19th century, organic solid insulation materials were mainly natural, such as paper, cotton, silk, and curable vegetable oil. These materials are flexible, meet the application process requirements, and are easy to obtain. Since the 20th century, the emergence of synthetic polymer materials has fundamentally changed the appearance of solid insulating materials.
Bakelite was first used as an insulating material. Later, polyethylene and polystyrene appeared. Due to their low dielectric constant and extremely small requirements, they met the requirements of high frequency and adapted to the development of new technologies such as radar. The silicone resin is combined with a low-alkali glass cloth to greatly improve the heat resistance level. Polyethylene formal is a paint-based enameled wire that opens up a broad prospect for enameled wire, replacing the wire and yarn envelope.
The thickness of the polyester film is only a few tens of micrometers, and it is used to replace the original paper and cloth, so that the technical and economic indicators of the motor and the electric appliance are greatly improved. The aramid fiber paper is used in combination with a polyester film or a polyimide film to make the heat resistance level of the motor slot insulation F grade and H grade, respectively. Similar developments have been made with elastomeric materials such as heat resistant silicone rubber, oil resistant nitrile rubber, and subsequent fluoroelastomers, ethylene propylene rubber, and the like.