rub·ber | \ rə-bər \ (noun)
Natural rubber was first identified and collected in Central and South American in about 1600 B.C.E. But the origin of the word we use now goes back to 1770, when chemist Joseph Priestley noticed that lines drawn with a pencil can be removed using rubber. That is, the pencil lines got "rubbed out". So, R U B B E R is derived from the English verb, "to rub out".
Standard Grade Rubber
Indeed there are different grades of natural rubber, a derivative of natural latex from the rubber tree or Hevea Brasiliensis.
The type of natural rubber product purchased depends on the application requirements, for example, a wetsuit, a yoga mat, or a running shoe will have different requirements than say a tire.
Manufacturers of rubber materials such as Yulex can engineer natural rubber with different additives to achieve a certain property for the application (aka "compounding").
Vietnam, Thailand, Malaysia and Indonesia all produce their own national Technical Specified Rubber (TSR). They are classified according to the source, e.g. latex or cup lump, and technical parameter. The TSR 10 or 20 grades are the most common grade, and predominantly used by the tire industry. It's made from field coagulated rubber or "cup lump". That is, the tree latex is coagulated in the actual collection cups on the tree at the plantation. The CV (Constant Viscosity) and L grades are made from tree latex (more on that later).
If you love how things are made like we do, then you need to check out our video of a TSR 10 (cup lump) process in Vietnam. Briefly, the cup lump is transferred to the factory, grinded, washed, pressed to remove water, grinded some more, packed into trays and dried in an oven, weighed and packaged into bales, labeled and ready for shipment. The rubber is tested for quality along the way.
If you're also a visual learner like me, check out our YouTube video.