Raychem Limited

Tyco Electronics Corporation

Martin Matthiesen

Lothar W Kleiner

Daniel A Chandler

Derek Leong

Matthew P Galla

Michelle Small

An electrical resistive device in which an element composed of a conductive polymer is positioned in contact with the surface layer of one or more metal electrodes. The metal electrode contains a base layer which includes a first metal, an intermediate metal layer which includes a metal that is different from the first metal, and a surface layer which (i) includes a second metal, (ii) has a center line average roughness {overscore (R )} of at least 1.3, and (iii) has a reflection density R of at least 0.60. The conductive polymer composition preferably exhibits PTC behavior density requirements, which may be, for example, circuit protection devices or heaters, have improved thermal and electrical performance over devices prepared with electrodes which do not meet the center line average roughness and reflection density requirements.

Electrically resistive PTC devices containing conductive polymers

Electrical devices containing conductive polymers

Diesel fuel is heated prior to filtration by passing it in thermal contact with a laminar heater immersed in the fuel. The heater has a resistance at room temperature of 0.30 to 0.75 ohm and comprises a PTC conductive polymer resistive heating element sandwiched between equispaced imperforate metal foil electrodes, particularly electrodeposited foil electrodes, coextensive with resistive heating element. The conductive polymer has a resistivity at room temperature of 20 to 2000 ohm - cm. The resistive element has a cross-sectional area in a plane parallel to the electrodes of 3 to 10 square inches and the electrodes have a microrough surface in direct physical contact with the conductive polymer.

Method and apparatus for electrically heating diesel fuel utilizing a

Electrical devices which comprise at least one metal electrode and a conductive polymer element in contact therewith, wherein the metal surface which contacts the conductive polymer has a roughened or otherwise treated surface to improve its adhesion to the conductive polymer. The metal electrode is preferably an electrodeposited foil. The conductive polymer preferably exhibits PTC behavior. The devices include heaters and circuit protection devices. The improved adhesion results in improved physical and electrical stability, and broadens the range of conductive polymer compositions which can be used in a number of important applications.

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Fremont, CA, United States of America

Martin Matthiesen