HIGH-MOLECULAR PTC COMPOSITION AND HIGH-MOLECULAR PTC DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a method of restraining an oxidative deterioration from occurring in a high-molecular PTC composition when subjected to a thermal history, where the PTC composition is composed of a binder whose main component is a crystalline high-molecular composition and metal carbide as conductive powder mixed into the binder and kneaded together.;SOLUTION: Transition metal functions as a catalyst to cause an oxidative deterioration to a high-molecular compound, so that a surface modifying agent film is formed on the surface of metal carbide powder so as to prevent the metal carbide powder from coming into contact with a binder. At this point, when the film is an insulator, it deteriorates the characteristics of a high-molecular PTC device, so that boron polymer is used as conductive surface modifying agent. Even if a high-molecular PTC device, which is composed of the high-molecular PTC composition and electrodes formed on both the sides of the PTC composition, undergoes a thermal history as it carries out a switching operation repeatedly, the oxidative deterioration occurs less in the binder, so that the binder is hardly increased in volume with the oxidative deterioration, and the high-molecular PTC composition varies less in resistiveity at a room temperature.;COPYRIGHT: (C)2003,JPO