Title: Pliable, fast-cure epoxy-fiberglass sheet molding compound with extensive out-life

Authors: Ruchir M. Shanbhag

DOI: 10.33599/nasampe/s.24.0125

Abstract: "Sheet molding compounds (SMCs) have existed for large scale industrial production of parts for many decades (1). These compounds consist of a B-staged resin (unsaturated polyester, vinyl ester, epoxy, etc.) along with fillers and discontinuous short fibers (glass, carbon, basalt, etc.) (2). These compounds are cut and pre-weighed into charges that are dropped in a mold cavity. They are then formed by compression molding under heat and pressure using matched-metal molds. The charge (weighed preform) of raw material going into the cavity before compression molding is determined by the density of the material and the volume of the final part. Conventional SMCs have mostly been made using unsaturated polyester and vinyl-ester resin matrices. The strength of most unsaturated polyester resin-based SMCs is limited (14), and the presence of styrene monomer in the resin is a growing concern across industries and governments (3). While some epoxy-based SMCs exist, they present processing challenges as they require storage in a freezer (for stability of the compound) and have a relatively slow cure rate. They also need to be heated to be sufficiently pliable to handle, cut and make into charges. Many factories that use conventional resin (unsaturated polyester and vinyl ester) based SMC do not have the infrastructure to handle epoxy resin-based SMC due to these limitations. We present a new epoxy-based SMC with no volatile organic compounds, excellent pliability at room temperature, and out-time stability for weeks without refrigeration. In addition to overcoming the longstanding challenges associated with conventional epoxy-based SMCs, the new material exhibits good thermo-mechanical properties."

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Conference: SAMPE 2024

Publication Date: 2024/05/20

SKU: TP24-0000000125

Pages: 15

Price: $30.00