Process for preparing thermoplastic elastomers by dynamic vulcanization

A process for preparing a thermoplastic vulcanizate, the process comprising the steps of:

• i. preparing a blend that includes a vulcanizable rubber, a first thermoplastic resin, a second thermoplastic resin, and a curative for the vulcanizable rubber, where the first thermoplastic resin is in its molten state, and where at least a portion of the second thermoplastic resin is in its solid state;
• ii. maintaining the blend at a temperature above the melt temperature of the first thermoplastic resin and below the melt temperature of the second thermoplastic resin, thereby maintaining the first thermoplastic resin in its molten state while maintaining the second thermoplastic resin in its solid state;
• iii. after said step of maintaining the blend, initiating the vulcanization of the vulcanizable rubber while the vulcanizable rubber is undergoing mixing with the first thermoplastic resin while in its molten state and the second thermoplastic resin while in its solid state;
• iv. after said step of initiating the vulcanization, allowing the vulcanization of the vulcanizable rubber to continue while allowing the second thermoplastic resin to melt and thereby form a blend that includes the vulcanizable rubber, the first thermoplastic resin, and the second thermoplastic resin, where both the first thermoplastic resin and the second thermoplastic resin are in their molten state;
• and
• v. after said step of allowing vulcanization to continue, allowing the blend to cool.