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US 2002/0177644 A1Published application
PTC conductive polymer compositions
AssigneeTherm-O-Disc, Incorporated
InventorEdward J. Blok
Life of this patent
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Abstract
The invention provides polymeric PTC compositions and electrical PTC devices with higher voltage capability and improved electrical stability. The PTC compositions include at a minimum an organic polymer and a conductive filler including carbon black having an iodine adsorption of less than about 60 mg/g carbon and a dibutyl phthalate absorption of greater than about 115 cc/100 g. Depending on device design, the composition can be used in low to high voltage applications.
Claims42
A polymeric PTC composition comprising:
- an organic polymer, a conductive filler including carbon black having an iodine adsorption of less than about 60 mg/g carbon and a dibutyl phthalate absorption of greater than about 115 cc/100 g, and, optionally, one or more additives selected from the group consisting of inert fillers, flame retardants, stabilizers, antioxidants, anti-ozonants, accelerators, pigments, foaming agents, crosslinking agents, coupling agents, co-agents and dispersing agents.
An electrical device which exhibits PTC behavior, comprising:
- (a) an organic polymer, a conductive filler including carbon black having an iodine adsorption of less than about 60 mg/g carbon and a dibutyl phthalate (DBP) absorption of greater than about 115 cc/100 g, and, optionally, one or more additives selected from the group consisting of inert fillers, flame retardants, stabilizers, antioxidants, anti-ozonants, accelerators, pigments, foaming agents, crosslinking agents, coupling agents, co-agents and dispersing agents;
- (b) at least two electrodes which are in electrical contact with the conductive polymeric composition to allow a DC or an AC current to pass through the composition under an applied voltage, wherein the device has a resistance at 25° C. of 500 mΩ or less with a desirable design geometry.
Dependencies are inferred from the claim text.