Tyco Electronics Corporation

Susan Melsa Jordan

Jianhua Chen

Masaaki Takahashi

John G Lahlouh

Edward F Chu

Kevin Michael Stein

Tsutomu Isozaki

A circuit protection device is formed from a resistive element composed of a PTC conductive polymer composition and two electrodes. The conductive polymer composition contains ethylene/vinyl acetate copolymer having a vinyl acetate component of less than 30% by weight of the copolymer, and a melting point of at most 105&deg; C. Devices of the invention have a resistive element thickness of 0.025 to 0.25 mm; a crosslinking level equivalent to 1 to 20 Mrads; a surface area of at most 120 mm ; a resistance at 20&deg; C., R , of at most 0.050 ohm; and a PTC anomaly from 20&deg; C. to (T &plus;5&deg; C.) of at least 10 . The devices can be used as part of an assembly in which the device is in contact with a battery, e.g. a rechargeable battery.

Electrical device and assembly

An electrically conductive polymer composition containing a polymer mixture containing a first crystalline polymer having a weight-average molecular weight of at least 50,000 and a second crystalline polymer having a weight-average molecular weight of at most 10,000, and a particulate electrically conductive filler has good processability and exhibits a low resistivity at 20&deg; C. and a good positive temperature coefficient (PTC) behavior.

Electrically conductive polymer composition

Processes and apparatus for melt extrusion of polymeric compositions, particularly conductive polymers, in which a gear pump delivers molten polymeric composition to an extrusion orifice. Overfeeding of the composition due to pressure variations is avoided by means of a polymer relief means, preferably a second, smaller gear pump, which removes a portion of the molten composition when the pressure exceeds a selected level.

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Mountain View, CA, United States of America

Susan Melsa Jordan