Extrusion of physically foamed rubber profiles

Abstract

Foaming of rubber profiles offers savings potential with respect to component weight, material consumption, and costs. Physical blowing agents are superior to chemical blowing agents in terms of economy, ecology, and efficient processing. The application of gear pumps in foam extrusion of ethylene propylene diene rubber compounds using nitrogen as blowing agent significantly improves the process stability due to minimized variations of process pressures. Experimental investigations show that the amount of blowing agent injected has a significant influence on density, foam structure, and surface roughness. Besides, the foam structure depends on die pressure and used materials. In addition to nitrogen, carbon dioxide and water are suited as well for the use as physical blowing agents.