Royaltherm 1721 a modified EPDM with a special silicone rubber.

Royaltherm 1721 is supplied as a base compound that can be vulcanized with peroxides or sulfur/accelerator systems. Royaltherm 1721 is 55 - 65 Durometer when vulcanized with 1.8 phr of dicumyl peroxide. It can be blended with Royaltherm 1411 for intermediate hardness applications.

Royaltherm 1721 is recommended for applications that require higher tensile strength than Royaltherm 1411. Royaltherm 1721 is also recommended for applications that require retention of mechanical strength at elevated temperatures, weather and moisture resistance, electrical stability and compression recovery at low temperatures.