Process for Continuous Foam Extrusion of Thermoplastic Polymers Via Syntactic and Chemical Foaming Agents

A process for producing an electrical insulative material. First there is produced a composition including a thermoplastic polymer resin selected from the group consisting of a polyethylene octene, a polyethylene hexene, a polyethylene heptene, a polyethylene nonene and a polyethylene decene; a filler selected from the group consisting of expandable polymer microballoons and glass microspheres; and a blowing agent comprising a physical blowing% agent and% a chemical blowing agent. The chemical-blowing agent is selected from one or more of the group consisting of an exothermic blowing agent and an endothermic blowing agent. This composition is then continuously foam extruded.