Electric heating element with polyester resin/soot conductive layer

Abstract From the Canadian patent

A heating element particularly one for large areas, consisting of an internal conducting layer with electrodes and of external non-conducting layers. The conducting layer is made of polyester resin mixed with soot in amount up to 10 per cent per weight. Electrodes being the external surface, of conducting layer are made in the form of a metallic grid carbon fibre or, of a perforated metal foil. To obtain good mechanical strength the conduct-, ing and insulating layers are preferably reinforced by glass fibre.