PCT heater cable composition and method for making same

摘要

A self-temperature regulating heater cable using a PTC polymeric matrix is described. A commercially available low density polyethylene is combined with a desired carbon black so as to enable a continuous extrusion at an elevated temperature while enabling residual heat in the extruded PTC layer to anneal the layer to a desired low resistivity in a short time period before quenching. The polyethylene is of the DFD-6005 type in which the amount of molecules whose molecular weight does not exceed about 23,000 is less than about eight percent by weight. The carbon black preferably is a low structure, low resistivity, non-surface treated, conductive carbon black.