Rubber

Hevea, the rubber tree

Natural rubber results from the coagulation of the latex from the rubber tree. This latex, not to be confused with the sap, flows in a separate network of specialized vessels in the bark of the tree: the lactiferous vessels. Obtained from the first latex transformation or coagulated cup lumps in the field, natural rubber does not contain any solvents.

Where does rubber grow?

Rubber is native to South America. Its cultivation has spread to all tropical regions, more specifically to Southeast Asia as well as West and Central Africa.

Rubber cultivation

Since the mid-twentieth century, all plantations have used selected plant material obtained through grafting. Rootstocks are raised in nurseries for six months before receiving a graft. These small rubber trees are then transplanted into the field, with a density of about 500 to 550 trees per hectare. After six years, they reach physiological maturity and the vegetative stage allowing for the start of tapping, through a fine incision in the bark to extract the latex. Rubber trees are a significant carbon sink, very useful in the fight against global warming. The rubber tree has a lifecycle of almost 30 years: when the trees’ yield decreases, the timber can be used for furniture, pulp or even firewood, or else it can be left in the field to decay naturally and maintain a good level of organic matter in the soil.

Harvesting

Harvesting starts with a fine incision in the bark of the tree. This operation makes it possible to transect the lactiferous vessels, allowing the latex to flow. It is harvested into cups placed below the tapping notch. Generally, tapping is done every 4 days, and the latex in the lactiferous vessels is renewed after harvesting.

Rubber can be harvested in a liquid state – latex – or after coagulation in the field (cup lumps). It is then taken to the rubber factory.

A simple and sustainable treatment process

At the factory, the cup lumps are stored in bunkers for several weeks before processing. Then this raw material is washed, mixed, granulated and dried several times before being pressed in 35kg bales. Strict adherence to quality standards throughout the processing process ensures compliance with end-users’ requirements. The finished product is then labeled “Technical Specified Rubber” (TSR).

Green energy supply

Our rubber factories are powered by green or renewable energy sources. Hence, our rubber dryers can be powered by wood of felled rubber trees or by electricity from solar, wind and hydroelectric installations.

Natural rubber is desired for its physical properties:

• Low thermal conductivity
• Elasticity
• Impact resistance
• Vibration and noise damping qualities

For more than 20 years, the Socfin Group has invested in research and development to ensure responsible tropical agriculture. Please have a look at our Research webpage and learn more about the various actions taken in the domain of rubber cultivation, among others.