Rubber comes from a milky white juice which some trees and plants have instead of sap. This liquid, called latex, can be found in the roots, stems, branches, bark, leaves, and fruit of over 400 different plants. Most latex, however, comes from the inner bark of the hevea, or rubber tree, of Brazil.
To get the latex, workers cut narrow slits in the bark of the rubber tree at daybreak, for the latex flows easily when the air is still cool. The latex is then allowed to drip into cups attached to the tree for three hours.
The latex, which is 2/3 water, is then taken to a rubber factory quickly, for it spoils easily. There, it is heated and mixed with acid. This process causes the latex to coagulate, or form solid curds. These curds are crude rubber.
This crude rubber is next pressed through rollers to remove the water. It comes out in the form of sheets, much like crepe paper. These sheets are hung up to dry, then packed in bales for shipment to rubber manufacturers.
Between 40,000 and 50,000 different products are made from rubber. These include automobile tires, gaskets, belts, printing rollers, boots, raincoats, combs, gloves, balls, rafts, toys, paints, and mattresses.
The English word “rubber” was first used in 1770, when Joseph Priestly, an English chemist, discovered that latex could “rub out” pencil marks!