MPET films are constructed with 1.9um–12um polyester plain film. The standard width is 620 mm.
A high vacuum is employed by a coating machine to melt, evaporate, and deposit high-purity zinc and aluminum on the base film. A metalized polypropylene film is then produced on the surface after an exceedingly thin metal layer has been formed.
The metalized film has a self-healing capability that enables it to return naturally to the electrical performance phenomenon prior to the breakdown after the partial breakdown of the film dielectric. To prevent metal from evaporating and to form the blank insulating strip known as the margin, the metalized film is covered on one or both sides of the edge or in the center. The margin's width is referred to as the margin in the following sentences.