Process enhancement of rubber compounding

Abstract

Mixing is the crucial step in the production of elastomers and determines elastomer properties. This work is focused on the influence of different process parameters on the compounding process for different mixer recipes. The goal of this work was to find out, how to get a good mixing quality and good elastomer properties, like a high tensile strength. Therefore, the influence of different mixing procedures and different process parameters defined by Semperit were evaluated. The first mixing step was done in an internal mixer and the intermixing with curatives was done on a rolling mill. Afterwards all samples were cured by compression molding. A variation of the classical mixing procedure "late oil addition" resulted in an especially high tensile strength, and no significant influence of one single process parameter was observed. In addition several methods to analyse the morphology of cured and uncured rubber samples were evaluated. Uncured samples could only be analysed by Raman spectroscopy, but an influence of sample preparation on morphology could not be excluded.