Preparation method of double-side metallized polypropylene capacitor film

Abstract

A preparation method of a double-sided metallized polypropylene capacitor film includes steps: firstly, preparing raw materials; secondly, using an extruder to extrude cast sheets; thirdly, using chilling rollers and air showering for cooling; fourthly, longitudinally stretching; fifthly, transversely stretching; sixthly, performing thickness measurement, edge cutting and corona treatment; seventhly, winding; eighthly, aging for the first time; ninthly, slitting; and tenthly, aging for the second time. The polypropylene capacitor film is subjected to double-side corona treatment during coronatreatment, the polypropylene capacitor film subjected to double-side corona treatment is further subjected to double-side metallized coating in the subsequent evaporation procedure, and since two sides of the polypropylene capacitor film are coated with metallized coatings, the thickening of the metallized coatings is not needed while the packaging size is not increased and the high-current bearing capacity of a prepared capacitor is not increased. In addition, the thickness of the double-sided corona polypropylene capacitor film with double-side metallized coatings is equal to that of an original polypropylene capacitor film with a single-side metallized coating, so that the problems of nonuniform thickness and proneness to disjointing are avoided, yield is high, and prepared capacitors are low in cost.

Description

technical field [0001] The invention belongs to the field of capacitor film preparation, in particular to a preparation method of a polypropylene capacitor film which can be metallized on both sides. Background technique [0002] Polypropylene capacitor film is a biaxially oriented polypropylene film for capacitors. The abbreviation of biaxially oriented polypropylene film is BOPP, which is the abbreviation of the English name of biaxially oriented polypropylene film "Biaxially Oriented Polypropylene". [0003] Film capacitors are divided into metallized film capacitors and metal foil capacitors. The usual method of making film capacitors is to use a metal foil such as aluminum as an electrode and a plastic film to overlap and then roll them together. However, there is another manufacturing method for film capacitors, which is called Metallized Film. In this way, the thickness of the electrode foil can be omitted and the volume of the capacitor unit capacity can be reduced...

AI Technical Summary

Problems solved by technology

[0004] At present, the metallized polypropylene capacitor film capacitors of the prior art generally use a single-sided metallized polypropylene capacitor film, that is, a polypropylene capacitor film in a single-sided corona treatment, but it has a major disadvantage of being durable The ability to withstand large currents is poor, because the single-layer metallized film layer is much thinner than the metal foil, and the ability to carry large currents is weak; to improve the shortcoming of metallized polypropylene capacitor film capacitors, there are two ways to improve : The first is to reduce the film width and increase the winding diameter, but the volume of the capacitor will increase accordingly, which is not conducive to the packaging of the circuit, and at the same time affects the development of the circuit towards miniaturization; the second is to increase the thickness of the metallized film layer thickness, it can be achieved without increasing the package volume, but the increase in the thickness of the metallized film layer is not conducive to the evaporation of the metal layer, and the metal layer is prone to uneven thickness during evaporation, and the metal layer is easy to be separated from the The polypropylene capacitor film is detached, the scrap rate is high, and the yield is low, resulting in high capacitor manufacturing costs

Therefore, there is the problem that the capacitor manufacturing cost is higher while the polypropylene capacitor film of the prior art does not increase the packaging volume and increases the high current carrying capacity of the prepared capacitor.