Patent ID: 6362721
Filing Date: 2002-03-26
Classification: H01C,H01M,Y02E

Abstract:
A circuit protection device which comprises(A) a resistive element which is composed of a PTC conductive polymer composition which comprises (1) a polymeric component comprising an ethylene/vinyl acetate copolymer having (a) units derived from a first monomer which is ethylene, (b) units derived from a second monomer which (i) is vinyl acetate, and (ii) comprises less than 20% by weight of the ethylene/vinyl acetate copolymer, and (c) a melting point Tm of at least 70Â° C. and at most 105Â° C., and (2) dispersed in the polymeric component, a particulate conductive filler; and (B) two electrodes which (1) are attached to the resistive element, and (2) can be connected to a source of electrical power, said device having the following characteristics: (i) a resistive element thickness of 0.025 to 0.25 mm; (ii) a crosslinking level equivalent to 1 to 20 Mrads; (iii) a surface area of at most 120 mm2; (iv) a resistance at 20Â° C., R20, of at most 0.050 ohm; and (v) a PTC anomaly from 20Â° C. to (Tm+5Â° C.) of at least 103.5.