Test MethodEvaluation of scratch resistance in multiphase PP blends

A study on scratch deformation behavior of multiphase PP/EPR/PE materials with different polymer composition was made by combining microscopic and macroscopic examination. The addition of PE to the PP/EPR blend leads to an improvement of scratch resistance. No strong correlation was found between micro- and macro-scratch experiments on the injection molded specimens, but when PE was added a reduction of the remaining deformation after scratching was found at both scales. The visibility of the scratches, which should be the most important parameter in daily use, is affected by the depth, the pile-up and the roughness of the scratch; the surface hardness does not play a role for the investigated polymers.