초록 ▼

The invention provides polymeric PTC compositions and electrical PTC devices that have a high voltage capability and are capable of operating at alternating current (AC) voltages of 110 to 130 volts or greater, such as those present in household AC electrical lines. The polymeric compositions demons

The invention provides polymeric PTC compositions and electrical PTC devices that have a high voltage capability and are capable of operating at alternating current (AC) voltages of 110 to 130 volts or greater, such as those present in household AC electrical lines. The polymeric compositions demonstrate a high PTC effect of at least 10.sup.4 to 10.sup.5 and a low initial resistivity at 25.degree. C. of 100 .OMEGA.cm or less, preferably 10 .OMEGA.cm or less, resulting in electrical PTC devices having a resistance at 25.degree. C. of 500 m.OMEGA. or less, preferably about 7.5 m.OMEGA. to about 200 m.OMEGA., typically about 10 m.OMEGA. to 100 m.OMEGA.. The devices of the invention can withstand a voltage of 110 to 130 VAC or greater without failure for at least 4 hours, preferably up to 24 hours or more, after reaching the switching temperature.

대표청구항 ▼

[ We claim:] [1.] A polymeric PTC composition comprising a crystalline or semicrystalline polymer including nylon-12, nylon-11, or mixtures or copolymers thereof, a particulate conductive filler, an inorganic additive and, optionally, an antioxidant, the composition having a resistivity at 25.degree

[ We claim:] [1.] A polymeric PTC composition comprising a crystalline or semicrystalline polymer including nylon-12, nylon-11, or mixtures or copolymers thereof, a particulate conductive filler, an inorganic additive and, optionally, an antioxidant, the composition having a resistivity at 25.degree. C. of 100 .OMEGA.cm or less and a resistivity at its switching temperature that is at least 10.sup.4 to 10.sup.5 times the resistivity at 25.degree. C., the composition being able to withstand a voltage of 110 to 130 VAC or greater while maintaining electrical and thermal stability.