Effect of planetary roller extruder on filler dispersion

摘要

Traditionally,many pressure sensitive adhesives(PSAs)are compounded in multi-step processes with the use of internal mixers,open mills for cooling and mixing of additional components downstream,or the use of high viscosity mixers for adding liquids,and then stored until used in a coating line.This discontinuous batch processing has high operating costs for personnel,material handling and storage,and is associated with the known quality problems resulting from batch-to-batch variations.For those processes,innovative technologies are in demand.One approach is the use of a planetary roller extruder(PRE).A planetary roller extruder(figure 1)is able to masticate,mix,homogenize,disperse and de-gas highly viscous substrates.Moreover,it can serve as a continuous reactor for chemical conversions; for example,in the range of highly viscous elastomer formulations.Thereby,the PRE presents its superiority over traditional batch reaction processes and diverse advantages when compared to other extrusion processes.The central unique features of the PRE include its remarkable large contact surface,the optimized heat transfer between processed material and heating/cooling medium,as well as its modular construction and the resulting manifold of possible system configurations.Depending on size and operation mode of the PRE,a large process window exists with scalable throughputs ranging from several kilograms up to much more than ten tons per hour.