Enhanced Breakdown Strength of Polypropylene Film for Capacitor by Deashing Method

In order to enhance the breakdown properties of Polypropylene (PP) for HVDC capacitors, a novel deashing method on the metal ash of PP is proposed in this paper. Four metal deactivators (MD) and ethanol (ET) are used for the deashing solution, and the PP powder is deashed by magnet stirring. The deashing parameters are optimized by the breakdown strength, including the MD content in the deashing solution and the deashing time. Results show that the deashed PP exhibits an enhanced breakdown strength and weakened conductivity compared with untreated PP, which is attributed to reduced metal ash content, including Ti, Fe, Mg and Al. Therefore, this deashing method can provide a reference for the improvement of breakdown strength and the research of the high-purity PP films for capacitors.