Performance of Specialty Minerals Precipitated Calcium Carbonates in Construction Silicone Sealant Formulation

Silicone sealants can be formulated to provide a wide range of performances that satisfy everything from household DIY (do-it-yourself) to more demanding fire-stop and insulating-glass applications. Preformance data generated in a generic, one-part silicone sealant formulation is presented here to help the formulator select the appropriate precipitated calcium carbonate (PCC) to satisfy the particular demands of the application.   


Three ultrafine PCCs were tested. These products varied in surface area, average particle size, and coating.


Application results show the impact of the PCCs on the rheological and mechanical properties of the sealant.Thixo-Carb® 500 PCC provides a lower modulus ideal for high elongation sealants. The Thixo-Carb® 300 PCC provides a high modulus and highest ultimate elongation. We recommend it for high-performance sealant applications. The Ultra-Pflex® PCC provides hardness and elongation similar to the Thixo-Carb® 300 PCC.