SEPTON ™ is a series of high-performance thermoplastic rubbers using isoprene technology. It consists of a series of hydrogenated styrenic block copolymers that exhibit rubber-like properties over a wide range of temperatures and hardnesses.
Prior to processing, the polystyrene end blocks are in rigid domains. In the presence of heat and shear, the polystyrene domains soften and flow. After cooling, the polystyrene domains re-form and harden, locking the rubber network in place. This physical phenomenon gives SEPTON ™ its high tensile strength and elasticity.
more info on Kuraray’s website.