Patent ID: 7497010
Filing Date: 2009-03-03
Classification: H01B,Y10T

Abstract:
1. A method of manufacturing a coaxial cable comprising: directing a conductor along a predetermined path of travel into and through a preheater and preheating the conductor; melting in a first extruder a thermoplastic polymer precoat composition; directing the preheated conductor into and through the first extruder and extruding onto the surface of the center conductor a continuous thin coating layer of the molten precoat composition; allowing the layer of precoat composition to cool and solidify forming a first bond interface (“A” bond) with the inner conductor; maintaining the temperature of the conductor and layer of precoat composition no more than 200° F.; directing the conductor and layer of precoat composition into and through a second extruder and extruding onto the coated conductor a foamable polymer composition, allowing the foamable polymer composition to expand, cool and solidify to form a foam dielectric surrounding the conductor with a second bond interface (“B” bond) between the layer of precoat composition and the dielectric; surrounding the foam dielectric with a continuous metallic sheath forming the outer conductor of the coaxial cable; and controlling the bond adhesion forces at the first and second bond interfaces so that the ratio of the axial shear strength of the first (“A”) bond to the axial shear strength of the second (“B”) bond is less than 1.