Importance of Foam Morphology to the Durability of Automotive Weatherstrips

Abstract

Elastomer automotive weatherstrips are generally constructed with a sponge bulb attached to a solid carrier. The sponge bulbs are manufactured by foaming and curing elastomer extrudates containing chemical blowing agents. The bulbs comprise a dense skin on the surface and a foamed core with relatively spherical cells at the center. In this study we have determined that the foam morphology of the sponge markedly affects the wear resistance and the knit line (between sponge bulbs and carriers) strength of the weatherstrips. The morphological parameters important to these durability related properties include skin thickness, surface texture, and cell structure. It is shown that the durability of automotive weatherstrips can be improved by controlling these parameters using proper compounding and processing techniques.