Raychem Limited

Arthur Edward Blake

Lee M Middleman

Joseph H Evans

Michael Peter Allenden

Victor A Scheff

A conductive material is provided which comprises a polymeric matrix having dispersed therein a conductive filler system comprising a minor proportion by weight of a relatively more conductive filler, and a major proportion by weight of a relatively less conductive filler. Preferred conductive materials may be used to provide stress relief for electrical apparatus and may be rendered heat recoverable.

Electrically conductive materials

Circuit protection devices which comprise two columnar electrodes and a conductive polymer element, at least a part of which is a PTC element. The device is so constructed that if a hot zone forms in the PTC element when current is passed through the device, it forms at a location away from the electrodes, thus increasing the useful life of the device. In one preferred embodiment, the conductive polymer element has an intermediate portion of increased resistance, thus causing the hot zone to be located at or near the intermediate portion. The intermediate portion may be of reduced size and/or be composed of conductive polymer of relatively high resistivity.

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Palo Alto, CA, United States of America

Arthur Edward Blake