低密度ポリエチレンフィルムの局所発熱現象に及ぼす熱処理及び延伸の影響

抄録

The authors already reported that localized heat generation appears before dc breakdown of low-density polyethylene film, which shows the contribution of thermal process to the breakdown. This paper describes the further study on the localized heat generation leading to dielectric breakdown in a low-density polyethylene film and the effect of heat treatment and elongation on it. To study the effect of density of polyethylene, very-low-density polyethylene (VLDPE) and high-density polyethylene (HDPE) films were also used. It was observed that the localized heat generation was suppressed after the heat treatment but was promoted after the elongation of the film. In VLDPE film, localized heat generation and dielectric breakdown occurred at obviously lower electric field than those in LDPE film. On the other hand, the localized heating was scarcely detected in HDPE film. These results indicate that the weak point where localized heat generation and breakdown occur might be one where local density or crystallinity is lower.