This International Standard specifies a method using the parallel-plate plastometer for the determination of the plasticity number and recovery number of uncompounded, compounded and reclaimed stocks of unvulcanized rubbers and rubber-like materials. NOTE The plasticity number and the recovery number are related to the viscoelastic properties of the material. The plasticity number is related to the flow properties and the recovery number is related to the elastic component. These are useful in predicting the processability characteristics, such as the ease of forming and die swell.