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Methods and devices which make use of conductive polymers to join articles

  • US 5,286,952 A
  • Filed: 12/18/1990
  • Issued: 02/15/1994
  • Est. Priority Date: 06/11/1987
  • Status: Expired due to Term
First Claim
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1. An elongate article which is in the form of a tape, which is not heat-recoverable, and which comprises:

  • (a) a conductive polymer element which(1) is in the form of a tape having a ratio of external surface area to polymer volume of at least 40 in2 /in3, an average thickness of 0.01 to 0.05 inch, a ratio of width to thickness of at least 20, and a ratio of length to width of at least 3;

    (2) is composed of a conductive polymer which(i) comprises a sintered polymeric component which consists essentially of ultra high molecular weight polyethylene which has a molecular weight of at least about 1.5 million, and, distributed in the polymeric component, a conductive particulate filler which consists essentially of carbon black present in amount less than 9% by volume,(ii) increases in volume by at least 10% when it is heated from 23°

    C. to the melting point of at least part of the polymeric component, and(iii) has a resistivity of 23°

    C. of 0.5 to 10 ohm-cm and exhibits ZTC behavior in the temperature range from 23°

    C. to the melting point of at least part of the polymeric component; and

    (3) has been prepared by skiving a sintered rod produced by ram extruding a dry blend of the polymeric component and the conductive filler; and

    (b) elongated electrode which are placed at opposite edge portions of the conductive polymer element, which can be connected to a source of electrical power and which, when connected to a suitable source of power, cause current to flow through the conductive polymer element and to generate heat in a heated section thereof, substantially all of the current which flows through the heated section flowing parallel to the plane of the element, the heated section consisting essentially of the conductive polymer, and the heated section having an area of at least 4 inch2.

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