Indicators representing the physical and mechanical properties of rubber:
Tensile strength: Also known as breaking strength or tensile strength, it refers to the load that the specimen can withstand per unit cross-sectional area when it is stretched until it breaks. The unit is megapascal (MPa), and previously it was kilogram-force per square centimeter (kgf/cm2). 2. Set elongation stress: Also known as set elongation strength, it refers to the load per unit area that a sample can withstand when it is stretched to a certain length. The unit of measurement is the same as that of tensile strength. Commonly used values include 100%, 300% and 500% set elongation stress. It reflects the degree of rubber's ability to resist external force deformation. 3. Tear strength: The load that a special test piece (with a slit or right-angle shape) can withstand when torn, representing the material's tear resistance. The unit is kN/m. 4. Elongation: When the specimen breaks, the ratio of the elongated part to the original length is called elongation; it is expressed as a percentage. 5. Permanent deformation: The percentage of the portion of the elongation deformation of the specimen after being stretched to fracture that cannot be recovered relative to the original length. After the external force is removed and a certain period of time (generally 3 minutes) is allowed to pass, it is expressed as a percentage. 6. Elasticity: Also known as impact elasticity, it refers to the ability of rubber to return to its original shape after being subjected to impact, expressed as a percentage. 7. Hardness: This refers to the ability of rubber to resist external force pressing into it. It is usually measured using a Shore hardness tester. The hardness range of rubber is generally between 20 and 100, with the unit being Shore A.