Scratch resistance of mineral-filled polypropylene materials

Pigmented mineral-filled polypropylene (PP-PMF) is marketed as a potential alternative to acrylonitrile-butyldiene-styrene (ABS) and Polycarbonate/ABS for automotive interior components. PP-PMF is more easily damaged by surface scratch/mar, thus limiting its acceptance for such applications. This study focuses on investigating the scratch/mar mechanisms of PP-PMF having different mineral fillers and additives. A new method is introduced to characterize the scratch visibility by image analysis. A correlation is found between scratch visibility and scratch hardness measured by interferometer. It is found that Wollastonite filler imparts higher scratch/mar resistance. Addition of an interface modifier and a lubricant can further improve scratch/mar resistance. It is also found that Talc-filled PP-PMF has poor scratch/mar resistance, irrespective of the addition of an interface modifier or a lubricant.