Hevea rubber
Natural rubber is obtained from the latex of some plants, among which Hevea Brasiliensis – hence the name. A sort of tree, the latter is the most important source of the product and is currently cultivated in large plantations in Brazil and the tropical belt of East Asia.
Further details are available under the heading “Did you know that…”.
Properties
- Heat resistance: up to a maximum temperature of 80 – 90°C. After a long exposure to high temperatures natural rubber tends to harden temporarily, but this may be followed by softening because internal links break.
- Resistance to low temperatures: up to about -55°C.
- Electrical properties: Properly proportioned mixtures feature a satisfactory insulating effect.
- Gas permeability: is high, so hevea rubber is not suitable when this is an issue.
- Resistance to ozone, ageing and weathering: rather limited. However, can be improved adding anti-ageing substances and ozone blockers such as protective wax.
- Resistence to chemicals:
- good to below average to:Water, alcohols, glycols and some peculiar ketones (e.g. ACETONE)
Glycol-based brake fluids
Silicone-based oil and grease
Diluted aqueous solutions of not very aggressive acids, bases and salts - Does not resist to:
Mineral oil and grease
Fuels, such as gasoline, kerosene and Diesel fuel
Hydrocabons like propane, butane, hexane, light gasoline, heptane, pentane.
Hydrocarbons in general.
Oxidizing agents like nitric and chromic acids, chlorine, bromine, etc.
- good to below average to:Water, alcohols, glycols and some peculiar ketones (e.g. ACETONE)
Applications
- All sorts of technical articles: hose, gaskets, membranes, rubber or metal/rubber spring elements, engine suspensions.
- Tires, belt conveyors, rubber belts.
- Other articles such as rubber boots, soles and heels, gloves, pacifiers (dummies), sponges, rubber threads, glues, etc.
