Natural Rubber (NR)
Natural rubber is primarily produced from the latex of the Hevea tree, and the chemical name of this polymer is polyisoprene. Natural rubber possesses many excellent physical properties including high resilience, high tensile strength, good abrasion resistance, and is extremely waterproof.
Natural rubber is found in:
- Electrical components
- Rubber gaskets and seals
- Rubber hose and tubing
Standard Compound: -50°C (-58°F) to 70°C (158°F)
Hardness: 40 to 90 Shore A
ASTM D1418 Designation: NR
ASTM D2000 Designation: AA
Standard Colors: Black
Natural rubber compounds are sulfur cured, and are usually mixed with SBR and BR for use in the production of tires.
Natural rubber performs well in alcohols and organic acids.
Natural rubber suffers from poor resistance to hydrocarbon oil. It is not suitable in UV, oxygen, and ozone because of the double bond in the polymer backbone. However, its poor weathering resistance can be improved with special additives. NR is often vulcanized to improve resistance and elasticity, and to prevent it from perishing.
Exposure to natural latex rubber products, such as latex gloves, can cause anaphylactic shock and other allergic reactions which has influenced the medical industry to move away from the use of natural rubber.