| 摘要 |
PURPOSE:To obtain an element having positive temperature dependence which has a high dielectric strength particularly against instantaneous overvoltage, by blending a mixture of a crystalline polymer and electrically conductive powder with an inorg. semiconductive material. CONSTITUTION:100pts.wt. mixture of 40-90wt% crystalline polymer and 60-10wt% electrically conductive powder is blended with 10-300pts.wt. inorg. semiconductive material having a specific resistance of 10<-2>-10<8>OMEGAcm. Examples of the crystalline polymer are high-density polyethylene, low-density polyethylene, polypropylene, polyamides, polyesters and mixtures thereof. Examples of the electrically conductive powder are carbon black, graphite, metallic powder, crushed carbon fiber and mixtures thereof. Examples of the inorg. semiconductive material are silicon carbide, boron carbide and mixtures thereof.
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