In a high vacuum condition, a coating machine melts, evaporates, and deposits high-purity zinc and aluminum on the base film. Following the formation of an incredibly thin metal layer, a metalized polypropylene film is created on the surface.
The metalized film has a self-healing function, and it naturally reverts to the electrical performance characteristic prior to the breakdown right after the partial breakdown of the film dielectric. The metalized film is covered on one or both sides of the edge or in the center to create a blank insulating strip without evaporating metal, which is known as the margin. The margin's width is also known as the margin.