by Joel Neilsen and Torsten Ziser, Lanxess
The efficient mixing of rubber compounds comes with many challenges. These include effectively blending the individual raw materials, which involves breaking down and blending different types of elastomers, adequately dispersing large fractions of fillers, oils and small weighments of chemicals in a relatively short time in the internal mixer. Once mixed, the compound then must be processed, e.g., extruded, calendered or molded to form the desired shape which is then vulcanized to produce the final product. The choice of the correct processing promotor will assist in these efforts. Certain promotors function primarily as dispersing agents, whereas others act more as lubricants to speed the mixed compound through the production process. Both types improve overall compound quality and production efficiency. Compound viscosity typically is also reduced. This article will focus on a number of processing promotors offered by Rhein Chemie and their effects on rubber compound quality and processability.