| abstract |
Disclosed are improved compositions useful in providing a conductive layer or coating on or within a conductor. The compositions contain elemental carbon and a polymeric matrix or binder. The improvement comprises employing a unique ground calcined, coal-based coke which approaches graphite in terms of its performance as a conductive additive or pigment but does not possess the disadvantages associated with the use of graphite. The unique coke employed in the compositions and methods of the present invention has a significant level of graphitic structure. This level of graphitization can be most easily recognized by utilizing x-ray powder diffraction. More specifically, when the value of Ec or the inverse peak width (using the 002 peak) is measured for this material using Mo K alpha radiation ( lambda =0.71 ANGSTROM ), the value is in the range of about 27 to about 80, and preferably about 28 to about 75. The final compositions employ a polymer resin or matrix system as a binder, preferably an acrylic emulsion or a fluoroelastomer. They are particularly useful as a sheath coating for elongated conductors such as automobile ignition cables. The invention also relates to the method of applying the compositions to the conductors, and the resulting coated conductor. |