| 摘要 |
PROBLEM TO BE SOLVED: To remarkably improve the moisture resistance of a positive temperature coefficient(PTC) thermistor while the thermistor maintains its excellent PTC characteristic at nearly the same level by mixing polyethylene oxide, a non-water soluble low-molecular organic compound, and conductive particles having spike-like projections in the thermistor. SOLUTION: An organic PTC thermistor is made of a kneaded product of polyethylene oxide (PEO), conductive particles having spike-like projections, and a non-water soluble lowmolecular organic compound. The weight-average molecular weight of the PEO is adjusted to about 2,000,000 or higher and the conductive particles are formed by connecting primary particles in chains. Such an organic compound having a molecular weight of about 1,000 or lower, a melting point between about 40 deg.C and about 100 deg.C, and wax or a functional group that can make hydrogen bond. Therefore, the thermistor can be operated at 60-70 deg.C at which human bodies are not endangered and the rate of resistance change of the thermistor from the nonoperating time to the operating time can be made larger by lowering the initial resistance when the thermistor is not operated. In addition, the moisture resistance of the thermistor is also improved.
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