Thermoplastic Foam Extrusion with Physical Blowing Agents

摘要

Consumer and business desire for high communication increases the market for high frequency cables in computer networks, CATV and GSM-systems. The optimization of electrical and mechanical characteristics of cable insulation by usage of foam techniques requires a good understanding of thermodynamical effects and their influence on the production process. This paper introduces to physical basics of manufacturing foamed polymers. Regarding cable insulation, polymer and gas selection is discussed, the technical demands are shown and an explanation of foam growth and stabilization is given. Using two cable types as example, an efficient way of checking foam equipment and/or production processes is presented. Therefore, a newly developed software is used, which calculates or simulates thermal and electrical behaviour of the foam with material and processing parameters as input.