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Self regulating heating device employing positive temperature coefficient of resistance compositions

  • US 4,658,121 A
  • Filed: 08/29/1985
  • Issued: 04/14/1987
  • Est. Priority Date: 08/04/1975
  • Status: Expired due to Term
First Claim
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1. A self-regulating heating article comprising at least two electrodes and a crosslinked electrically conductive polymer composition, the electrodes being connectable to a power supply so that current will pass between the electrodes through the conductive polymer composition, said composition having a positive temperature coefficent of resistivity and comprising (1) a first polymeric material which prior to cross-linking exhibits significant green strength corresponding to a tensile stress of at least 10 psi at 20% elongation and which exhibits elastomeric properties at ambient temperatures in the crosslinked state;

  • (2) a second thermoplastic polymer material; and

    (3) conductive particles which have been dispersed in said polymeric material such that the composition exhibits increased resistance with increased temperatures at temperatures substantially above the melting point of either material.

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