Polymers have been added to road asphalt for several years to decrease low temperature cracking, reduce softening at high temperatures, and increase longevity. They are also added in higher concentrations to roofing shingles and water proofing products. Regardless of the specific end product, the process is very similar and can benefit from the addition of an IKA® Works Mixer or Mill.
The traditional process involves heating the asphalt oil to 300-450oF and adding 10-15% polymer crumb (typically SBS or recycled tire rubber). Depending on the batch size and type of polymer added (tire rubber does not cross-link and therefore takes less time / energy to blend), the solution is then processed with either a high speed in tank mixer or inline colloid mill. Next, the product has additional ingredients added (i.e. CaCO3 filler in roofing asphalt) or is let down to 3-5% SBS (road asphalt). The challenges to the processor include adding the polymer to the liquid stream, quickly dispersing or solubilizing the polymer, and finding equipment to operate cost effectively in this service. Working with IKA® allows asphalt companies to address all of these concerns.