Abstract: A process for preparing thermoplastic rubbers from vulcanized rubber scrap material is provided comprising devulcanizing the vulcanized rubber scrap material while blending the vulcanized rubber scrap material with an olefinic plastic resin in the presence of devulcanizing additives. Preferably, the vulcanized rubber scrap material is first milled prior to blending with the olefinic plastic rein. The plastic resin may be a virgin resin, a recycled resin or a mixture thereof. The process is termed “dynamic de-vulcanization” to denote that the rubber scrap material is being devulcanized while it is being blended with the plastic resin to form the thermoplastic rubber. The resultant thermoplastic rubbers exhibit superior physical properties such as tensile strength, elongation, hardness and flexural modulus compared to thermoplastic rubber compositions comprising mixtures of plastics and recycled rubbers heretofore produced.