Royaltherm 1421 Silicone modified ethylene-propylene diene terpolymer Crompton-Uniroyal Chemical Rubber - Elastomer >> Ethylene-propylene diene terpolymer, EPDM SEALANT >> Pre-formed tape / Gasket ROYALTHERM 1421 is a modified EPDM with a special silicone rubber. ROYALTHERM is supplied as a base compound that can be vulcanized with peroxides or sulfur/accelerator systems. ROYALTHERM 1421 is 35 - 45 Durometer when vulcanized with 1.8 phr of dicumyl peroxide. It can be blended with 1721 for intermediate hardness applications. ROYALTHERM 1421 is recommended for applications that require lower tensile strength than 1721. ROYALTHERM 1421 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. It has superior overall heat resistance to 1411. Automotive - radiator and heater hose, ignition cable, spark plug boots; appliance wire, molded electrical goods; architectural gaskets; expansion gaskets. Ethylene-propylene diene terpolymer modified with a special silicone rubber. Used as a base compound in gaskets. Can be vulcanized with peroxides or sulfur/accelerator systems. Provides low tensile strength, retention of mechanical strength at elevated temperatures, weather and moisture resistance, electrical stability and compression recovery at low temperatures. Possesses superior heat resistance. Applications : automotive - architectural and expansion gaskets.