The Importance of Residence Time Analysis in Coextrusion Die Design

Abstract

This paper emphasizes the importance of analyzing the residence time distribution of the polymer when designing extrusion systems and why this analysis is especially important for coextrusion systems. An analysis of the relationship between pressure drop and residence time for different die geome tries shows how the potential for problems to occur is higher for coextrusion dies. An example is presented of how changing the layer ratio of a coextrusion product can lead to long residence times which may result in poor product qual ity and possibly damage the system.