Many rubber bands are made from natural rubber that has been processed, while others are made from synthetic rubber. Natural rubber comes from the sap of the rubber tree. Synthetic rubber polymers are made from petroleum-based chemicals.
Natural rubber goes through several processes before it can be transformed into rubber bands and other products. Latex fluid is obtained by tapping rubber trees. The fluid is clumped by adding acid and rolled into sheets. A mill then removes the water. The latex is then treated with chemicals and heated to prevulcanize it. Synthetic rubber polymers are mixed, clumped and rolled into sheets. After processing, both types of rubber can be manufactured into rubber bands.