A maker of sheet molding compound (SMC) released what it says is an ultra-low density SMC formulation to add to its low-density composite products.

Core Molding Technologies’ progress of SMC Lightweighting. Image source: Business WireCore Molding Technologies’ progress of SMC Lightweighting. Image source: Business Wire Core Molding Technologies Inc., which also molds fiberglass-reinforced thermoset and thermoplastic compounds, says its ultra-low density Hydrilite SMC has a nominal density of 0.98 sp.gr. (specific gravity) while exhibiting mid-range mechanical performance and a high-quality surface appearance. That places the SMC system below the density of water and below most thermoplastic systems.

SMC composite material is a ready-to-mold glass or carbon fiber reinforced polyester material primarily used in compression molding. Among Core’s markets are medium- and heavy-duty truck, marine, automotive, agriculture, and construction.

Core said the new product represents a nearly 50% reduction from standard-density SMC materials and a 17% reduction from its own lightweighting materials that include its Airilite and Econolite SMC systems. Those products test at 1.18 sp.gr.

Hydrilite is formulated with a high-performance resin system and is reinforced with 41% glass fiber by weight, which Core said results in a material system more economical and less dense than those based on carbon fiber. Hydrilite SMC achieves nominal tensile strength of more than 75 MPa (megapascals) and impact strength of 850 J/m.

The company says those results and the mechanical properties of the system, make it applicable to lightweighting applications that require a combination of strength and high appearance. A molded product that weighs 100 pounds in standard-technology SMC would weigh 51 pounds in Hydrilite SMC.

A commercial program using Hydrilite SMC is undergoing customer qualification, and other applications are in development. The company is working to develop a version of the product that retains the 0.98 sp.gr. density and adequate mechanical performance.

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