Core Molding Technologies Inc. (Columbus, Ohio) on Oct. 10 announced a new ultralow-density sheet molding compound (SMC) formulation and an addition to Core’s suite of low-density composite product offerings. Hydrilite SMC has a nominal density of 0.98 specific gravity and exhibits what is said to be mid-range mechanical performance and a high-quality surface appearance. The achievement places the SMC system below the density of water and below most thermoplastic systems. The breakthrough represents a nearly 50% reduction in specific gravity compared to standard-density SMC materials, and a 17% reduction compared to Core’s Airilite and Econolite SMC systems, which test at 1.18 specific gravity
“Across our markets, customers continue to challenge us to lower the density of fiberglass reinforced material systems to support their lightweighting efforts,” says Terry O’Donovan, vice president, marketing and sales for Core Molding Technologies. “A density of 1.0 specific gravity, equivalent to the density of water, has long been seen as a practical limit by formulation chemists throughout the thermoset industry. To be the first to crack that barrier and achieve a functional system at 0.98 specific gravity is a high achievement for our development team and a meaningful product advance for our customers.”
Hydrilite SMC is formulated with a high-performance resin system and is reinforced with 41% glass fiber by weight. It offers nominal tensile strength of more than 75 MPa and impact strength of 850 J/m. Both results are on par with Core’s standard-density reinforcement-grade SMC formulations. This performance, along with other mechanical properties of the system, are said to make it ideal for a broad range of lightweighting applications requiring a combination of strength and good appearance. A commercial program using HydriliteTM SMC is undergoing customer qualification, and other applications are in development.
O’Donovan says Core is working to develop a full Class-A version of the product, while retaining the 0.98 specific gravity density and adequate mechanical performance. Evaluation plaques and material performance data for Hydrilite SMC are available to qualified customers.