Goodyear hit pay dirt first, in 1839. By slow-cooking latex with sulfur, he finally discovered a process to transform rubber into a durable material with nearly limitless applications. He sent some of the new rubber to his brother-in-law, a textile manufacturer, who immediately saw the potential, incorporating rubber into men's shirts to create the shirred, or ruffled, effect that was popular at the time. Goodyear also sent samples to British rubber companies. Eventually, a few pieces ended up in the hands of Thomas Hancock, who reverse-engineered Goodyear's sulfur-based manufacturing technique. In 1843, Hancock filed for a patent for the process, which he now called vulcanization, after Vulcan, the Roman god of fire.
Now, finally, the rubber boom could begin in earnest. New companies emerged and rubber products -- from shoes to sheets -- flooded the market. In 1845, Stephen Perry and Thomas Barnabas Daft of London invented the modern rubber band by slicing narrow rings from a vulcanized rubber tube. Today, manufacturing rubber bands happens in much the same way. First, workers create rubber by mixing latex with a range of chemicals depending on the desired elastic qualities. Then they extrude the raw rubber compound so it forms a long, hollow tube. They slip this sleeve of rubber over a round pipe known as a mandrel and expose the material to high heat and pressure. This is the vulcanization process, which cures the rubber and stabilizes it indefinitely. Finally, they cut narrow bands of rubber from the end of the tube, wash and dry them, then package them for shipment.
Rubber threads are made in the same way, except they're cut from sheets of rubber instead of tubes. These slivers of natural rubber make their way to textile manufacturers, who weave the stretchy threads, with natural-fiber yarns, into elastic products. Some manufacturers also use threads from synthetic elastic materials.