VOLTAGE STRESS-RESISTANT CONDUCTIVE ARTICLES

摘要

Described herein are methods and means by which conductive carbon black-containing resistive heaters which are self-temperature limiting by reason of their positive temperature coefficient of resistance are stabilized against long-term resistance variation under high voltage stress, variously by (a) increasing the proportion of carbon black at the electrode interface relative to that of the remainder of the semi-conductive material of which the article is comprised; and (b) providing at the electrode interface a material selected from the group consisting of carboxylic acid group-containing polymers of acid number greater than 3, their ammonium, alkali or alkaline earth metal salts, or a polymeric amine of amine number greater than 3.