There are many ways for plastic classification, such as: heat resistant property, hygroscopicity, chemical composition,
crystallinity, application field or special purposes. Hygroscopic plastic: The inside of colloidal contains moisture, like PA
(Nylon), ABS, PET, PC, PS.
Non-hygroscopic plastic: The surface of Micelles contains moisture, like PE, PP.
Rubber product has its particular use function and formula technology requirements. In the process of producing rubber products, the physical characteristics which need to be tested are as follows: tensile strength, tear strength, stress at definite elongation and hardness, wear resistance, fatigue and Fatigue damage, flexibility, tore elongation. There is an affinity between physical properties as above and rubber density.