A composite impregnating agent capable of improving the service life of metallized film capacitors and its preparation method

Abstract

The invention relates to a composite impregnant capable of substantially prolonging the service life of a metallic film capacitor and a preparation method of the composite impregnant. The composite impregnant comprises, by weight, 7.0 parts to 8.5 parts of modified soybean oil, 2.5 parts to 4.5 parts of polyisobutene, and 1.0 part to 3.0 parts of modified molecular sieves. The preparation method of the composite impregnant comprises the modified soybean oil preparation step, the modified molecular sieve preparation step and the composite impregnant preparation step. According to the composite impregnant, the amount of water generated in the raw material production process and the using process can be effectively reduced, namely, the negative factors influencing the service life of the metallic film capacitor are further reduced, and therefore the service life of the metallic film capacitor is prolonged, the failure rate of the metallic film capacitor is reduced, and the metallic film capacitor is used more safely and reliably. In addition, the composite impregnant has lower dielectric loss and a lower thermal expansion coefficient, and is better in thermal stability, and favorable for substantially prolonging the service life of the metallic film capacitor.

Description

technical field [0001] The invention relates to an impregnating agent for metallized film capacitors, in particular to a compound impregnating agent capable of improving the service life of metallized film capacitors and a preparation method thereof. Background technique [0002] At present, the impregnating agents used in metallized film capacitors are generally vegetable oils such as castor oil and salad oil, or mineral oils such as methyl silicone oil and benzyl silicone oil. The biggest disadvantage of simply using oil as the impregnant for metallized film capacitors is that the oil will inevitably contain some water, and during the use of metallized film capacitors, the water will gradually penetrate into the capacitor core, causing metal The Zn-Al metal layer on the surface layer of the polypropylene film of the thin film capacitor dissolves, falls off or oxidizes, which causes the capacity of the capacitor to decay quickly or even easily decays and fails, and also mak...

AI Technical Summary

Problems solved by technology

Although these oils can be vacuum dehydrated in advance, some manufacturers of metallized film capacitors have begun to do so, but this not only requires more complicated equipment and costs a lot, but the most important thing is that it cannot prevent these oils from dehydrating. Such secondary moisture will adversely affect the life of metallized film capacitors

In addition, if only these oils are used as impregnants, there are disadvantages such as high dielectric loss, poor thermal stability, and high thermal expansion coefficient, which will also adversely affect the life of the capacitor.