TPV concentrate: Fabrication and performance

Thermoplastic vulcanizates (TPVs) have been widely studied and applied in recent years because of their excellent elasticity and re-processibility similar to those of thermoplastics. However, its dynamical vulcanization processing normally requires an expensive twin-screw extruder with a very high L/D ratio. In this paper, a kind of thermoplastic vulcanizate concentrate (TPVC) with very high rubber phase content and low hardness was prepared by using highly oil-extended ultra-high molecular weight ethylene propylene diene rubber (EPDM) dynamically cured by peroxide and a low melt index polypropylene (PP) and extra oil softener. Then a new kind of high purity TPV with a wide hardness range was fabricated by using this TPVC simply melt blended with various contents of PP. The mechanical and recycling properties, rheological responses, phase morphology, crystallization, thermal stability and UV radiation resistance were systematically studied. In addition, because TPVC is filled with a large amount of white oil, the process parameters can be controlled reasonably by studying the distribution coefficient of white oil in the two phases.