Compaction of Fillers, Flame Retardants and other Additives to Improve Flowability and Accelerate Compounding Rate

摘要

A process has been developed to compact fillers commonly used in plastics to improve mechanical properties - mica, nanoclays and wollastonite - and flame retardance - magnesium and aluminum hydroxides. Such fillers are produced in very fine particle size or high aspect ratio. They are fluffy, entraining much air, which must be removed. Aerated fillers do not flow well and require special feed devices. Voluminous filler takes up machine capacity, limiting the production rate of filled compounds. Entrained air reduces thermal conductivity and thus the flux rate of the polymer. Compaction improves the handling, feeding and incorporation rate of such fillers into compounds.