FRICTION INDUCED PAINT DAMAGE AS AFFECTED BY CLEARCOAT CHEMISTRY

One form of damage to automotive painted plastic composites, in partic ular thermoplastic bumpers and fascias, is known to be caused from com pressive shear loading placed on the surface of the composite. The loa ding inflicted upon the composite by a stationary force (e.g. an autom obile hitting a post) or a moving object (e.g. an automobile hitting a nother automobile), and consequent compressive shear that is induced, can result in cohesive delamination of the substrate. The cohesive del amination in the painted composite (herein referred to as 'gouge') is not only influenced by the cohesive strength of the substrate but also by the mechanical properties of the coating. Our studies indicate tha t one important attribute of the coating, namely the coating's coeffic ient of friction, can significantly impact the 'gouge' resistance of t he painted composite. In this work, we will describe the derivation of coating attributes as they affect 'gouge' resistance and relate chang es in the coating chemistry to useful life parameters. (C) 1997 Elsevi er Science S.A.