Patent ID: 8076416

Claim:
A thermoplastic vulcanizate including: i. a cured rubber, where the rubber is cured to an extent where not more than 3 wt % of the rubber within the thermoplastic vulcanizate is extractable in cyclohexane at 23° C., and where the rubber is a copolymer of ethylene, propylene, and a diene; and ii. from about 20 to about 400 parts by weight of a thermoplastic resin component per 100 parts by weight rubber; where said thermoplastic resin component includes at least 0.1 percent by weight and less than 4.5 percent by weight, based upon the entire weight of said thermoplastic resin component, of a high-viscosity, long-chain branched polypropylene homopolymer that is devoid of α,ω-diene units characterized by a melt flow rate of less than 10 dg/min, an M w in excess of 300,000, M w /M n in excess of 4.0, and a viscosity average branching index, <gN> vis , of less than 0.7, where the balance of the thermoplastic resin component includes isotactic polypropylene but excludes a crystallization agent, where the rubber is dynamically cured in the presence of the high-viscosity, long-chain branched polypropylene homopolymer and the isotactic polypropylene, and where the thermoplastic vulcanizate exhibits a second recrystallization temperature, as determined by differential scanning calorimetry at 10° C. in nitrogen, that is at least 8.47% greater than a similar thermoplastic vulcanizate that includes isotactic polypropylene as the entire thermoplastic resin component.