The MPET film base material is 1.9um-12um polyester plain film. The normal width is 620mm.
The high-purity zinc and aluminium are melted, evaporated, and deposited on the base film by a coating machine in a high vacuum state, and a metallized polypropylene film is formed on the surface after an extremely thin metal layer is formed.
The metallized film has a self-healing effect, and it instinctively returns to the electrical performance phenomenon before the breakdown immediately after the partial breakdown of the film dielectric. For the actual production of capacitors, the metallized film is covered on one or both sides of the edge or in the middle to form a blank insulating strip without evaporating metal, which is called the margin, and its width is called the margin. In addition, the resistance of the metal layer on the metallized film in the unit square area is called sheet resistance, expressed in Ω/□ or ohms, and the same city uses sheet resistance to represent the thickness of the metal layer.