Basic Studies of Extrusion of Rubber Compounds in a Pin Barrel Extruder

Abstract

Abstract An experimental study of the flow, pumping, and mixing characteristics of three different rubber-carbon black compounds in a model pin barrel extruder is presented. These are a model SBR/BR passenger tire compound, a NR truck tire compound, and a NBR mechanical goods compound. Comparisons are made of the initial extruder without pins or slices/grooves in the screw flights, an extruder containing slices or grooves in its flights, and a pin barrel extruder. It is found for each compound that introducing slices in screw flights improves mixing/homogenization and decreases pumping ability. Introduction of pins improves mixing/homogenization and has little effect on pumping. The homogenization is best for the passenger tire tread compound and worst for the NBR mechanical good compound.