Applications of chemo-rheology to develop process windows in reactive in-mold coating

In-Mold Coating (IMC) products have been used for many years to enhance the surface properties of Sheet Molding Compound (SMC) compression molded reinforced plastic parts. IMC provides a smooth, sealed surface which can be used as a conductive primer for subsequent finished-paint operations and in some cases as a substitute for paint altogether. Painting is a very costly and non-environmentally friendly operation. Thus, a new class of coating materials is being developed for thermoplastic substrates. In this paper, we measure the kinetics and chemo-rheology of a typical IMC used for SMC compression molded parts and for a proposed IMC candidate for thermoplastics. We show how chemo-rheological measurements can be used to establish process windows.