Crosslinked SBR in block copolymer compounds to achieve certain EPDM TPV Performance

Masterbatches of crosslinked solution-polymerized styrene-butadiene random elastomers (XL-SBR) and polypropylene (PP) were prepared and used for enhancing the oil resistance, compression stress relaxation performance, and lowering compression set of styrene-ethylene/butylene-styrene (SEBS)-based thermoplastic elastomer (TPE) compounds. Enhanced performance was achieved when SBR partly or substantially replaced the SEBS component. Modification of SEBS compounds in the Shore A range of 45-85 with the crosslinked SBR is discussed and the effect of SEBS molecular weight is also investigated. Addition of crosslinked SBR to SEBS compounds provides improved compression set and oil resistance performance that is similar or better than a commercial EPDM TPV tested in the Shore A 60-67 range.