Effect of erucamide and silica loadings on COF behavior of POP multilayer films in repetitive testing

Abstract

AbstractErucamide is incorporated into polymer films to reduce their coefficient of friction (COF). Such COF reduction is important in packaging lines where the performance of the film in contact with rollers can be governed by the frictional characteristics of the film. This research explores the COF behavior of multilayer films with either polyolefin plastomer (POP) or linear low‐density polyethylene (LLDPE) as the skin layer. Film‐on‐metal COF testing was performed repetitively with the same piece of film to investigate the extent of COF change with the number of runs for cast and blown films. Results showed that the COF of the film increased with the number of runs and plateaued at a higher steady state value. Complementary analysis conducted with atomic force microscopy (AFM) revealed that initially erucamide was removed from the film surface exposing the bare polymer film to the metal plate, but as more runs were performed the erucamide crystals were smeared over the film surface re‐covering the previously exposed film surface. Several combinations of slip and antiblock (AB) loadings were used to study their effects on the steady state COF obtained from repetitive testing on blown films. Results showed that the steady state COF decreased with the addition of both slip and AB, except for the lowest chosen loadings of 1250 ppm slip and 3000 ppm AB.