Reducing Variability in Dart Measurement Associated with Dart Head Wear, 2005 PLACE Conference

Discrepancies in results from dart impact testing of films are a common occurrence. In order to evaluate potential explanations for these differences, a study was initiated to explore the effect of dart head wear and additive formulation on dart performance. Results from this work indicated that dart head wear can lead to variation in results after testing 1000 samples. When evaluating dart impact behavior on a variety of films using new and conditioned dart heads, it was observed that the degree of impact resistance and the formulation of the film both had a significant effect on results. Samples with relatively poor impact performance were less sensitive to dart wear, as were samples which had been formulated with antiblock and slip. The sensitivity of dart to additive formulation was found to be caused by the coefficient of friction of the film, as samples with low coefficient of friction showed minimal dependence on the condition of the dart head. Based on findings from this work, NOVA Chemicals has instituted a program address these concerns. This initiative will ensure that excessive dart wear does not generate unacceptable discrepancies in dart performance.