Royalene 390 Ethylene-propylene diene terpolymer Crompton-Uniroyal Chemical Rubber - Elastomer >> Ethylene-propylene diene terpolymer, EPDM SEALANT >> Pre-formed tape / Gasket ROYALENE ® 390 Excellent green strength, low die swell and shrinkage. Fast, smooth extrusion rate. Excellent low temperature properties. Construction profiles / window gaskets. Molded mechanical goods. Gaskets. Ethylene-propylene diene terpolymer (EPDM). Used in gaskets. Provides very good green strength, low die swell and shrinkage, fast and smooth extrusion rate, and very good low temperature properties. Applications: window gaskets.