E-b Industries, Inc.

General Signal Corporation

Ensign-bickford Industries, Inc.

Cornelius J Kelly

PTC Devices and PTC compositions described herein comprise a blend of at least three carbon blacks as a particulate filler in a fluorinated polymer to achieve a substantial PTC effect and operability over a wide temperature range including temperatures prevailing in a steam environment. Two of the carbon blacks are selected to impart PTC effect to the composition. The third carbon black is selected to adjust the resistive properties of the composition into the range of commercial usage and to impart uniformity of the resistive properties within a given batch as well as from one batch of mix to the next.

PTC devices and their composition

The method of manufacturing, composition and product described herein utilize highly electrically resistive carbon black alone or with low resistivity carbon black to form a self-limiting electrically resistive semi-conductor which presents a positive temperature co-efficient of resistance, the methods which are described providing significantly shortened anneal times, manufacturing ease and reliability.

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Simsbury, CT, United States of America

Cornelius J Kelly