Hot melt thermoset/thermoplastic hybrid prepregs: Effects of B‐stage conditions on the quality of composite parts

Abstract Prepregs are highly expensive, and most customers rely heavily on suppliers. The product may not always be optimized for specific applications, but it is sometimes the only commercially available option that works. To address these issues, there is a need to produce prepregs in‐house. In this article, we will describe the methodology for creating thermoset/thermoplastic hybrid prepregs using hot melt with B‐stage cured epoxy resin film. We investigated the choice of materials and the proportion of thermoplastics through DSC and rheology measurements. Additionally, we analyzed the time and temperature of B‐staging to achieve high‐quality composite parts. Multiple ways for preparing prepregs exists, each involving few different steps. We will explore some of these methods using a hydraulic press before scaling up to a prepreg filmer machine. Our focus will be on evaluating the quality of the final composites under various conditions and comparing them to composites produced with commercially available prepregs. Highlights In‐house thermoset/thermoplastic hybrid prepreg fabrication optimization procedure. Material characterization prior to fabrication to ensure B‐staging repeatability. Investigation of several methods of prepreg fabrication. Optimized procedure to achieve high‐quality surface finish for composite parts.