Royaltherm is a silicone-modified EPDM. It is ideally suited for high temperature applications. Compared to normal EPDM, Royaltherm provides better heat and weather resistance. Compared to silicone, it provides better tensile strength, flex fatigue resistance and other mechanical properties. It exhibits good electrical properties in moist conditions and, unlike silicone, retains physical properties even in hermetically sealed environments.
There are 2 grades of Royaltherm available. Both may be crosslinked with either peroxide or accelerated sulfur cure systems. Additional compounding additives are not required to make useful rubber parts. Royaltherm 1721 provides a vulcanizate with 70 Shore A hardness; Royaltherm 1411A, 35 Shore A. The two products may be blended to achieve intermediate hardness products. Additional additives may be incorporated for special properties. For example, chemical foaming agents can be incorporated to make cellular products.