Thermosetting Resins for Compression Molded Articles with Reduced Styrene Odor
Demands from Original Equipment Manufacturers (OEM), air permitting, and public perception all continue to drive demand for reduced volatile organic compound (VOC) emissions in sheet molding compound (SMC) and products produced in the press molding market space. In this paper, several unsaturated polyester resin systems were designed to reduce residual styrene content in compression molded plaques. Typical propylene glycol-maleic anhydride (PG-maleate) resin systems were mixed with low molecular weight mono- and dimethacrylate crosslinkers to reduce initial styrene content and increase reactivity. Impact on processing parameters, such as flow and viscosity, was minimal. Residual styrene content in compression molded plaques was measured with head space gas chromatography. It was determined that lower initial styrene content in resin formulations had a positive impact on residual styrene in the molded article. Residual styrene was decreased up to 75% in some cases, without the use of post-processing ovens. Additionally, standard profiling additives were shown to maintain effectiveness in controlling linear shrink in molded plaques.
Authors: Eric S. Powell, Rob L. Seats, and Laura K. Gigas
Conference: CAMX 2016 – Anaheim