Abstract: A PTC heater assembly comprises at least one PTC heater surrounded by an envelope of high thermal conductivity, thus greatly increasing the power output of the heater under operating conditions. In a preferred assembly a strip heater, comprising (i) an elongate strip of a conductive polymer PTC composition, (ii) electrodes embedded in said strip, and (iii) an insulating jacket, is sandwiched between a pair of metal, e.g. aluminum, sheets.

Abstract: A PTC heater assembly comprises at least one PTC heater surrounded by an envelope of high thermal conductivity, thus greatly increasing the power output of the heater under operating conditions. In a preferred assembly a strip heater, comprising (i) an elongate strip of a conductive polymer PTC composition, (ii) electrodes embedded in said strip, and (iii) an insulating jacket, is sandwiched between a pair of metal, e.g. aluminum, sheets.

Abstract: An element comprises a support, preferably a continuous polymeric film, and fibrous material, preferably a spun glass fiber web, which is secured to the support and protrudes therefrom, the protruding fibrous material being part of a layer comprising randomly distributed fibers having solid material, especially particulate material, adhered thereto. The element can be prepared from a composition containing solid material dissolved or dispersed in a liquid medium by applying said composition to fibrous material which is partially embedded in one surface of a support and then drying to evaporate the liquid medium.

Abstract: An electrically conductive element comprises a support (perferably a flexible continous polymeric film) and fibrous material (preferably a spun glass fiber web) which is partially embedded in the support and partially protruding therefrom, the protruding fibrous material being part of a conductive layer comprising randomly distributed fibers having conductive material adhered thereto. The element can be prepared from a conductive composition containing conductive particles dispersed in a liquid medium (preferably an aqueous dispersion of carbon particles) by applying said composition to a substrate comprising a support and fibrous material which is partially embedded in one surface of the support and partially protruding therefrom, and then drying to evaporate the liquid medium. The elements are particularly useful as heating elements which comprise electrodes so that current can be passed through the conductive layer.

Abstract: A PTC heater assembly comprises at least one PTC heater surrounded by an envelope of high thermal conductivity, thus greatly increasing the power output of the heater under operating conditions. In a preferred assembly a strip heater, comprising (i) an elongate strip of a conductive polymer PTC composition, (ii) electrodes embedded in said strip, and (iii) an insulating jacket, is sandwiched between a pair of metal, e.g. aluminum, sheets.